JP3378259B2 - How to create a contact structure - Google Patents

Abstract

Microelectronic contact structures (260, 360, 460) are lithographically defined and fabricated by applying a masking layer (220, 320, 420) on a surface of a substrate (202, 302, 402) such as an electronic component, creating an opening (222, 322, 422) in the masking layer, depositing a conductive trace of a seed layer (250, 350, 450) onto the masking layer and into the openings, and building up a mass of conductive material on the conductive trace. The sidewalls of the opening can be sloped (tapered). The conductive trace can be patterned by depositing material through a stencil or shadow mask (240, 340, 440). A protruding feature (230, 430) may be disposed on the masking layer so that a tip end (264, 364, 464) of the contact structure acquires a topography. All of these elements can be constructed as a group to form a plurality of precisely positioned resilient contact structures.

Description

DETAILED DESCRIPTION OF THE INVENTION Cross Reference to Related Applications This patent application was filed by Pedersen and Khandros 1998 2
"MICRO ELECTRONIC CONTACT STRUCTUR"
This is a continuation-in-part of co-pending U.S. patent application Ser. No. 60 / 073,679, entitled "ES," which is hereby incorporated by reference herein. .

This patent application also applies to Eldridge, Khandros, Mathieu and P.
Co-pending US patent application Ser. No. 08 / 852,152 (currently pending) filed May 6, 1997 by edersen and owned by the applicant and its corresponding PCT filed May 15, 1997 Patent application No. US97 / 08634 (current situation, November 20, 1997)
Published as WO97 / 43654 on the day)
Both of which are hereby incorporated by reference herein, and both are hereinafter referred to as the "parent application."

TECHNICAL FIELD OF THE INVENTION The present invention relates to elastic (spring) contact (interconnect) elements (structures) suitable for achieving pressure and / or compliant connections between electronic components, and more Specifically, it relates to a microminiature contact structure.

BACKGROUND OF THE INVENTION By Eldridge, Grube, Khandros and Mathieu 1995 1995
Co-pending US patent application Ser. Nos. 08 / 452,255 (currently pending) and 19
Corresponding PCT patent application No. US95 / filed November 13, 1995
No. 14909 (currently published as WO95 / 14909 on June 6, 1996) discloses a method for making elastic interconnection elements for microelectronics. This mounts one end of a flexible elongate core element (eg, the "axis" or "skeleton" of the wire) to a terminal on an electronic component, the flexible core element and the " Coating with a "shell". The shell is made of one or more materials arranged in a given combination of thickness, yield strength and elastic modulus such that the resulting spring contact has a given force-deflection characteristic. Gold is an example of a material for the core element. Examples of coating materials include nickel and its alloys. The resulting spring contact element can be used to make a pressure or releasable connection between two or more electronic components, especially microelectronic components including semiconductor devices.

The parent application mentioned above discloses manufacturing a spring contact element by depositing at least one layer of a metallic material in an opening defined in multiple mask layers deposited on the surface of a substrate. There is. The substrate can be an electronic component such as an active semiconductor device. Each spring contact element has a proximal end, a contact end, and a central body. In one of the embodiments disclosed in the parent application, the contact ends are offset (offset) along the z axis from the base end (at different heights), and the x and y directions are also different. Is offset along at least one of In this way, a plurality of spring contact elements are manufactured on the substrate in a predefined spatial relationship to each other. These spring contact elements make a temporary (ie pressure) or permanent (eg soldering or brazing, or conductive adhesive bond) connection to the terminals of another electronic component between them. Make an electrical connection. In an exemplary application, these spring contact elements are disposed on semiconductor devices that are on a semiconductor wafer, thereby allowing semiconductors to be burned in and / or tested prior to being cut one by one from the semiconductor wafer. It is possible to make a temporary connection with the device.

Similar to the case of the parent application, the present invention is also directed to interconnecting the latest microelectronic devices in which terminals (bonding pads) are arranged at a fine pitch,
It is also particularly suitable for this. As used herein, the term "fine pitch" refers to five terminals.
References are made to microelectronic devices spaced less than a mil, such as 2.5 mils or 65 micrometers. As will be apparent from the description below, this preferably provides the precise tolerances that can be easily achieved by using lithographic techniques rather than mechanical techniques to manufacture the contact elements. It is achieved by utilizing.

Eldrid, incorporated herein by reference herein
Co-pending U.S. patent application Ser. No. 08 / 955,001 (currently pending) filed Oct. 20, 1997 by ge et al., also owned by the applicant, also has terminals (bonding pads) with fine pitch. It is intended and particularly suitable for interconnecting modern microelectronic devices that are deployed. As described in that application, the spring contact elements can be manufactured in an area on the electronic component separate from the terminals to which they are electronically connected,
These terminals are electrically connected via conductive lines. The conductive line extends from the terminals of the electronic component to a position away from these terminals. In this way
Mounting a plurality of substantially identical spring contact elements on an electronic component in a pattern with their free ends positioned spatially displaced from the pattern of terminals on the electronic component. You can Spring contact elements include, but are not limited to, composite interconnect elements and plated finish structures. Electronic components include, but are not limited to, semiconductor devices, memory chips, portions of semiconductor wafers, spatial deformers, probe cards, chip carriers, and sockets.

SUMMARY OF THE INVENTION It is an object of the invention to provide improved techniques for manufacturing spring contact elements.

Another object of the present invention is to provide a technique for manufacturing spring contact elements using a process that is inherently well adapted to the field of microelectronic fine pitch, precision tolerance. .

Another object of the present invention is to provide a technique for manufacturing a microminiature spring contact element directly on an active electronic component such as a semiconductor device without damaging the semiconductor device. This involves fabricating ultra-fine miniature spring contact elements on the semiconductor devices that are present on the semiconductor wafer, prior to singulating the semiconductor devices from the semiconductor wafer alone.

Another object of the present invention is to provide a spring contact element suitable for socketing (one form for detachably connecting) an electronic component such as a semiconductor device, such as performing burn-in to the semiconductor device. It is to provide a technology for manufacturing.

According to the present invention, a microelectronic contact structure applies a mask layer on a surface of an electronic component, creates an opening in the mask layer, deposits conductive traces on and in the mask layer,
It is then manufactured by building up a mass of conductive material on the conductive traces. Each lump of conductive material represents a contact structure having a proximal end extending upward through the opening, a main body extending across the mask layer (on the conductive trace), and a tip. become.

According to one aspect of the invention, the sidewalls of the openings in the mask layer can preferably be tapered (sloped). Disclosed herein are techniques for forming tapered openings.

According to one aspect of the invention, conductive traces can be deposited on the mask layer using a stencil (shadow mask).

According to one aspect of the invention, the opening in the mask layer that defines the proximal end of the selected one of the contact structures can be located on the contact pad of the electronic component. Alternatively, the opening in the mask layer that defines the proximal end of the selected one of the contact structures can be located away from the contact pad, with respect to the contact pad being below the mask layer. Connected by a patterned conductive layer at.

According to one aspect of the invention, a protruding feature is deposited on the mask layer, whereby the tip of the contact structure is
Offset from main body of contact structure
You can

Electronic components include, but are not limited to, active semiconductor devices, memory chips, portions of semiconductor wafers, spatial deformers, probe cards, chip carriers, and sockets. In other words, the electronic component may be a passive device to support one or more electronic connections. Particularly preferred is the addition of the microelectronic contact structure of the present invention to active electronic devices, especially silicon semiconductor devices.

The contact structure of the present invention is suitable for making a temporary or permanent electrical connection to the terminals of another electronic component, such as a printed circuit board (PCB) interconnect substrate.

In order to make a temporary contact, the part on which the contact structure is manufactured is put together with other electronic parts so that the tip of the contact structure makes a pressure connection with the terminal of the other electronic part. To do. The contact structure reacts elastically (in an elastic deformation mode), maintaining contact pressure and electrical connection between these two parts.

In order to make a permanent connection, the component on which the contact structure is manufactured is joined together with other electronic components, and the tip of the contact structure is soldered to the terminal of the other electronic component and soldered. Attaching or joining by using a conductive adhesive or the like. The contact structure is compliant and able to accommodate the differential thermal expansion between these two parts.

The contact structure of the present invention, on the surface of a semiconductor device,
Alternatively, it can be directly manufactured on the surface of a plurality of semiconductor devices existing on the semiconductor wafer. In this way, a plurality of semiconductor devices present on a semiconductor wafer can be made "ready" for burn-in and / or testing prior to separate slicing from the semiconductor wafer. .

According to one aspect of the invention, the tapered openings in the mask layer are used as tapered areas in the seed layer and in the final contact structure formed on the seed layer. Appear in.

Other objects, features and advantages of the invention will be apparent in light of the following description of the invention.

Briefly, the present invention is directed to the fabrication of one or more microelectronic contact structures. These structures are
Applying a mask layer on the surface of the electronic component, creating an opening in the mask layer, depositing a seed layer on and in the mask layer (preferably as a conductive trace), and a conductive material on the conductive trace. Can be manufactured by building a mass of. The sidewalls of the opening can be tapered. Techniques for tapering the sidewalls of an opening are disclosed. The conductive traces can be deposited via a stencil (shadow mask), thereby avoiding the need for additional mask layers. Protruding features, such as dots of insulating material, can be deposited on the mask layer so that the tips of the resulting contact structures have a topology. The mass of electrically conductive material has a substantially hemispherical cross section as built on the seed layer. The opening in the mask layer defines the proximal end of the contact structure and may cover the contact pad of the electronic component, or it may be spaced apart and connected to the contact pad by a conductive trace. it can.

Significant differences between the technology of the present invention and the technology disclosed in the parent application include, but are not limited to:

a) In the parent application, the contact structure is constructed in a multi-level trough, which is in a multi-level mask layer. Generation of such multi-level troughs is relatively complex when compared to the relatively straightforward technique of the present invention. The invention includes forming openings (222) in mask layer (220), but the mask layer is preferably a single mask layer and can be patterned in a single step.

b) The technique of the present invention facilitates the formation of tapered sidewalls (eg, of the opening 222), which occurs from one level of the contact structure (eg, its proximal end) to another level of the contact structure. Brings a smooth transition to (eg, its main body).

c) The "third level", ie the tip of the contact structure, is defined by the relatively simple means of a protruding feature (230), such as another trough in another mask layer. Contrasts.

d) The overall shape (geometry) of the contact structure is defined by and built on the conductive traces (250) rather than within the trough. As a general matter, it is somewhat easier and more reliable to plate “on” something (ie a conductive trace) than to “in” something (ie a trough). It is also controllable. For implementing curved (as opposed to linear) contact structures, this greatly simplifies patterning.

e) The overall shape of the contact structure in the x-axis and y-axis directions (assuming the electronic component has a surface in the xy plane) is
It is basically defined by a stencil or shadow mask. In contrast, the x-axis and y-axis shapes in the parent application are basically defined by patterning the various layers of mask material.

BRIEF DESCRIPTION OF THE DRAWINGS Reference will now be made in detail to the preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. These drawings are intended to be illustrative, not limiting. Although the present invention is described in the context of these preferred embodiments, it should be understood that it is not intended to limit the spirit and scope of the invention to these specific embodiments. Certain elements in the figures, selected from the accompanying drawings, are shown not to scale for clarity of illustration. In many cases, elements that are similar throughout the figures are designated by like reference numbers. Element 199, for example, is likely similar in many ways to element 299 in another figure. Also, often, similar elements are designated with similar numbers in the same figures. For example, multiple elements 199 may be designated as 199a, 199b, 199c, and so on.

FIG. 1A is a side cross-sectional view of a technique for making a spring contact element, as disclosed in the parent application.

FIG. 1B is a side cross-sectional view of the spring contact element of FIG. 1A as disclosed in the parent application.

FIG. 1C is a perspective view of the spring contact element of FIG. 1B as disclosed in the parent application.

FIG. 2A is a side cross-sectional view of one step of a first exemplary embodiment of a process for making a contact structure according to the present invention.

FIG. 2B is a side cross-sectional view of another step of the first exemplary embodiment of a process for making a contact structure in accordance with the present invention.

2C is a top plan view of the intermediate product formed in the step shown in FIG. 2B, according to the first exemplary embodiment of a process for making a contact structure according to the present invention.

FIG. 2D is a side cross-sectional view of another step of the first exemplary embodiment of a process for making a contact structure in accordance with the present invention.

FIG. 2E is a side cross-sectional view of another step of the first exemplary embodiment of a process for making a contact structure in accordance with the present invention.

2F is a top plan view of the intermediate product formed in the step shown in FIG. 2E, according to the first exemplary embodiment of a process for making a contact structure according to the present invention.

FIG. 2G is a side cross-sectional view of another step of the first exemplary embodiment of a process for making a contact structure in accordance with the present invention.

FIG. 2H is an end cross-sectional view of the product formed in the step shown in FIG. 2G, according to the first exemplary embodiment of a process for making a contact structure according to the present invention.

2I and 2J are perspective views of two of the many possible configurations for the contact structure of the present invention, highlighting the funnel-shaped proximal end. FIG. 2I illustrates a structure obtained by partially coating the sidewalls of the opening, as generally shown in FIGS. 2E and 2G. FIG. 2J shows the structure obtained by completely coating the sidewalls of the opening, as shown in FIGS. 4E and 4G.

2K is a top plan view of the intermediate product formed in the step shown in FIG. 2G, according to a first exemplary embodiment of a process for making a contact structure in accordance with the present invention.

2L and 2M are side cross-sectional views and perspective views, respectively, of a completed contact structure formed on an electronic component, according to a first exemplary embodiment of a process for making a contact structure according to the present invention. It is a figure.

FIG. 2N is a side cross-sectional view of the contact structure of FIGS. 2L and 2M according to the present invention with the tip in contact with the contact pad of the electronic component.

FIG. 2O is a side cross-sectional view of the contact structure of FIGS. 2L and 2M according to the present invention with the tip soldered to the contact pad of the electronic component.

FIG. 3A is a side cross-sectional view of one step, comparable to the step shown in FIG. 2D, in a second exemplary embodiment of some of the processes for making contact structures in accordance with the present invention.

3B is a side cross-sectional view of another step, comparable to the step shown in FIG. 2E, in a second exemplary embodiment of some of the processes for making contact structures according to this invention.

FIG. 3C is a side cross-sectional view of another step, comparable to the step shown in FIG. 2K, in a second exemplary embodiment of some of the processes for making contact structures in accordance with the present invention.

3D is a side cross-sectional view of the optional augmentation structure with tip and post structures added to the structure of FIG. 3C.

FIG. 4A is a side cross-sectional view of one step, comparable to the step shown in FIG. 2A, in a third exemplary embodiment of a process for making a contact structure in accordance with the present invention.

FIG. 4B is a side cross-sectional view of another step, comparable to the step shown in FIG. 2B, in a third exemplary embodiment of a process for making a contact structure in accordance with the present invention.

4C is a top plan view of the intermediate product formed in the step shown in FIG. 4B, according to a third exemplary embodiment of a process for making a contact structure in accordance with the present invention.

FIG. 4D is a side cross-sectional view of another step, comparable to the step shown in FIG. 2D, in a third exemplary embodiment of a process for making a contact structure in accordance with the present invention.

FIG. 4E is a side cross-sectional view of another step, comparable to the step shown in FIG. 2E, in a third exemplary embodiment of a process for making a contact structure in accordance with the present invention.

4F is a top plan view of the intermediate product formed in the step shown in FIG. 4E, according to a third exemplary embodiment of a process for making a contact structure according to the present invention.

FIG. 4G is a side cross-sectional view of another step, comparable to the step shown in FIG. 2G, in a third exemplary embodiment of a process for making a contact structure in accordance with the present invention.

FIG. 5A is a side cross-sectional view of a technique for creating openings in a mask layer on a substrate according to the prior art.

FIG. 5B is a side cross-sectional view of an opening created in a mask layer on a substrate according to the prior art.

FIG. 5C is a side cross-sectional view of another technique for creating openings in a mask layer on a substrate, according to the prior art.

FIG. 5D is a side cross-sectional view of a technique for creating a tapered opening in a mask layer on a substrate according to the present invention.

FIG. 5E is a side cross-sectional view of another technique for creating a tapered opening in a mask layer on a substrate according to the present invention.

FIG. 5F is a side cross-sectional view of another technique for creating a tapered opening in a mask layer on a substrate according to the present invention.

FIG. 6A is a top plan view of one embodiment of a tip of a contact structure according to the present invention.

FIG. 6B is a top plan view of another embodiment of the tip of the contact structure according to the present invention.

FIG. 7 is a top plan view of a preferred embodiment of the spring shape according to the present invention.

FIG. 8 shows a stencil for forming and transferring a protruding feature according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Before describing the techniques of the present invention and the resulting microelectronic contact structures, it is useful to briefly review the techniques described in the parent application. There is some commonality between the materials and processes employed by the present invention and those of the parent application, and both are both directed to the fabrication of microelectronic contact structures, perhaps spring contact elements. However, noteworthy and significant differences will be apparent from the following description.

FIGS. 1A-1C show a microelectronic contact structure that is a spring contact element by depositing at least one layer of metallic material into an opening defined in multiple mask layers deposited on the surface of a substrate. 3 illustrates a technique for manufacturing a body. This substrate can be an electronic component such as an active semiconductor device, as disclosed in the aforementioned parent application. In general, a number of insulating layers in which openings are formed are aligned and a layer of conductive material is "seeded". The seeded openings are then electroplated (or CV) with a mass of conductive material.
It can be formed (or deposited) by a method such as D, sputtering, or electroless plating. After the insulating layer is removed, the mass can function as a self-supporting elastic contact structure. The contact structure extends not only vertically on the surface of the electronic component, but also laterally from the position where it is mounted. In this way, the contact structure is x
Easily made to be compliant in both the -y plane (parallel to the electronic component surface) and the z-axis direction. Since the three-dimensional relationship is generally deformed, moved, and rotated, the term "above" in FIGS. 1A, 1B, and 1C should be understood only in the meaning of the drawings, and Should remain within the teachings of.

FIG. 1A illustrates an exemplary technique for making one of a plurality of self-supporting resilient (spring) contact elements 120 on a substrate 102. Substrate 102 can be, for example, a semiconductor device or other active electronic component, such as a semiconductor device residing on a semiconductor wafer.

Substrate 102 has a plurality of regions 112 (one of many) on its surface.
One of which is shown), in which the spring contact element is manufactured.
If the substrate 102 is an electronic component (such as a semiconductor device), then these regions 112 are preferably the terminals of the electronic component (such as bonding pads).

In general, the techniques involved include a number of patterned mask layers 104,106 (showing three layers) with openings.
And 108 on the substrate surface. These layers are patterned to have openings (as shown) that are aligned with regions 112, and those openings are such that the openings in one layer (eg, 108, 106) are lower layers (eg, 108). 106 and 104) and are sized and shaped to extend further out of the region 112 than the openings in each. In other words, the opening that the first layer 104 has is the region 112.
It is above. Some of the openings in the second layer 106 are in the first layer 1
Aligned with at least a portion of the opening in 04, and conversely, a portion of the first layer 104 underlies a portion of the opening in the second layer 106. Similarly, some of the openings in the third layer 108 are
Of at least a portion of the openings in layer 106 of the second layer 106, and vice versa, a portion of the second layer 106 underlies a portion of the openings of the third layer 108. For the entire given opening, the bottom is above the selected area 112 and the top is lifted from the bottom. A conductive metallic material is deposited in these openings and the mask layer is removed, resulting in a free-standing contact structure, as described in more detail below. The structure was manufactured directly on the substrate with its proximal end secured to the substrate 102 in region 112, and its free end was above the surface of the substrate and from region 112. It is displaced laterally and extends.

If necessary for electroplating, etc., use a thin conductive material such as titanium-tungsten (Ti-W) (for example, 45
A 0 nm) "seed" layer 114 may be deposited in the opening. Then, a mass 12 of conductive metallic material (eg nickel).
It is possible to deposit 0 in the openings by electroplating.

1B and 1C show the resulting spring contact element 120, with the proximal end 122 adjacent the region 112 and the free end (tip) 124 lifted in the z-axis direction from the surface of the substrate 102. And laterally offset from the base end portion 122 in the x-axis and y-axis directions.

As best seen in FIG. 1C, the contact structure 120 is responsive to pressure applied in the z-axis direction at its tip 124, as indicated by arrow 132, which does not result in another electronic component (FIG. Terminal (not shown) (not shown)
Occurs when making a temporary, pressure-based electrical connection. Compliance along the z-axis ensures that the contact force (pressure) is maintained and also between terminals (not shown) on other electronic components (not shown). Address non-flatness (if any). Such temporary electrical connections are useful for making temporary connections to the electronic component 102, such as for burn-in and / or testing of the electronic component 102.

The tip 124 is also free to move compliantly in the x-axis and y-axis directions, as indicated by arrows 136 and 134, respectively. This joins (soldering, brazing, etc.) the tip portion 124 to a terminal (not shown) of another electronic component (not shown) having a thermal expansion coefficient different from that of the substrate (electronic component) 102. Or with a conductive adhesive). Such permanent electrical connections allow electronic components, such as multiple memory chips (each represented by substrate 102), to be connected to another, such as an interconnect substrate, such as a printed circuit board ("PCB", not shown). It is useful for mounting on electronic parts.

With proper selection of materials and geometry, the mass 120 thus produced can function as a self-supporting resilient contact structure, manufactured with precise dimensions and very precise spacing from each other. . For example, tens of thousands of such spring contact elements 120 can be easily and precisely manufactured on the same number of terminals on a semiconductor device that are present on a semiconductor wafer (not shown).

The resulting spring contact element 120 is basically preferably made entirely of metal and can be formed (manufactured) as a multi-layer structure. Suitable materials for one or more of the layers of the contact structure are described in the parent application. One representative of such materials is nickel (and its alloys).

Thus, the parent application describes a method of manufacturing spring contact elements 120 directly on a substrate 102, such as an electronic component such as a semiconductor device residing on a semiconductor wafer. This applies at least one layer 104, 106, 108 of mask material on the surface of the substrate 102, the mask layer being patterned to extend from a region 112 on the substrate, spaced above the substrate surface and lateral to the region 112. Laterally and / or laterally offset locations, and optionally seeding these openings by depositing at least one layer of a conductive metallic material within the openings.
By removing the mask material and leaving the conductive metal material to form free-standing contact elements extending from the substrate surface. Each contact element has a proximal end fixed to one of the areas of the substrate and a distal end for making electrical contact to the terminals of the electronic component.
As will be apparent from the following description, the technique of the present invention is
At least in certain aspects, it dramatically simplifies the manufacturing process of microelectronic contact structures.

Exemplary Processes of the Invention The process described above with respect to FIGS. 1A-1C uses three layers of mask material 104, 106, 108 that must be applied patterned and stacked on top of each other, resulting in a material Obtaining a multi-level trench where 120 must be deposited.

According to the present invention, similar microelectronic contact structures (hereinafter "contact structures") can be manufactured with fewer layers of mask material (eg photoresist). Figure
2A to 2L illustrate an embodiment of the present technique.

FIG. 2A illustrates an exemplary electronic component 200 on which multiple contact structures can be manufactured. In the majority of the following, the fabrication of a single contact structure 260 will be described as illustrating the fabrication of multiple such contact structures, preferably all simultaneously on the same electronic component. Typically, each of the contact structures fabricated on a single electronic component are substantially identical (ie, in size, shape, etc.) to each other, but depending on the requirements of a given application, It is within the scope of the invention for the designer to individually control and determine the size and shape of each contact structure.

In this example, the electronic component 200 is a semiconductor device, and includes a silicon substrate 202 and a passivation layer (for example, polyimide having a thickness of 4 μm) arranged on the silicon substrate 202.
204 and a plurality of openings 206 (one of many shown) extending through the passivation layer 204 to the metal contact pads 208. Typically, there are multiple such contact pads on an electronic component. In the complete assembly, each contact pad has a separate electronic component (not shown), such as a thin profile package (TSOP).
Commonly (i.e. according to the prior art) connected (e.g. with bonding wires) to the corresponding contact pads above.

As shown in FIG. 2A, in the first step of the process, conductive layer 210 is deposited. This conductive layer 2
10 is, for example, titanium-tungsten (Ti-W),
It can be deposited by sputtering to a thickness of 300-600 nm, for example about 450 nm. The conductive layer 210 is substantially the surface of the passivation layer 204, the sidewalls of the opening 206,
And exposed metal contact pad 208 (within the opening)
The surface is continuously covered with the same shape. The conductive layer 210 is preferably electrically conductive and, when deposited as a continuous "blanket" layer, electrically shorts all the contact pads 208 of the electronic component together. As will be apparent from the description below, this shorting capability of the conductive layer 210 is advantageous for establishing a suitable potential for an electrolytic process (eg, electroplating) for making contact structures on electronic components. It can be used.

It is also within the scope of the invention that conductive layer 210 be patterned rather than continuous and can be deposited as multiple, non-continuous areas. In the preferred embodiment, conductive layer 210 covers the exposed surface of terminal 208. In an alternative embodiment, conductive layer 210 covers only a portion of terminal 208. In another alternative embodiment, the conductive layer 210 does not cover the terminals 208 at all, but is located in a general area of the terminals 208 so as to make contact with the conductive layer 210 when the seed layer 250 is applied. It

In addition, a second conductive layer (412, described below) made of another material (eg, gold) is used as the conductive layer 210 (similar conductive layer 41).
It is also within the scope of the invention to deposit and pattern on (see 0, which is explained in the description of FIG. 4A). This can be used, for example, to locally interconnect and route signals from contact pad 208 to contact structure 260. Two layers are generally preferred for many applications. Selection of the appropriate material is within the ability of one of ordinary skill in the art.

Although a passivation layer is typically present on the semiconductor device, it is also within the scope of the invention that the contact pad 208 is on or in the surface of the substrate 202 itself (not yet exposed) without the passivation layer 204. It is inside. Prior to depositing conductive layer 210, passivation layer 2
The conductive layer 210 to the passivation layer 204 is optionally first "roughened" 04 (if it is present).
It is also possible to improve the adhesiveness of. This is simply
It can be achieved by exposing the electronic component 200 to an oxygen (O ₂ ) plasma with suitable parameters (which can be easily determined by those skilled in the art) to obtain the desired surface texture on the passivation layer. Material selection is also
It also affects the adhesion of the seed layer to the passivation layer. Titanium-Tungsten (Ti-W) or copper, for example, are known to adhere well to polyimides.

In the next step of the process, as shown in FIG. 2B, a layer 22 of mask material (eg photoresist) is used.
0 is deposited on the surface of component 202 (ie, on conductive layer 210),
It is patterned (eg, using conventional photolithography techniques) to include an opening 222 that extends completely through the mask layer 220. The opening 222 can be located above the opening 206 in the passivation layer 204 (as shown) or can be located away from the opening 206 and away from the contact pad 208 (as described below). .

By locating opening 222 away from contact pad 208, as described in more detail below,
A plurality of contact structures on the electronic component can be manufactured with a different layout than that of the contact pads of the electronic component. One particularly preferred configuration is aperture 222.
Is arranged so that the contact structure constructed thereon has the tips arranged in an area array comparable to the ball grid array. These openings can be connected, for example, to contact pads on electronic components arranged as peripheral pads. Advantageously, the contact structures are substantially identical without displacement from the contact pads. Useful in this case is to place the openings 222 in an array of areas corresponding to the array of tips of the final contact structure.

Each opening 222 preferably has an area greater than the area of opening 206 on contact pad 208. For example,
The square contact pad 208, which measures 4 mils x 4 mils (ie 100 μm x 100 μm), has an exposed area of 10,000 μm ²
And a square aperture 222 measuring 200 μm × 200 μm
Is 40,000 μm ² (4 of the exposed area of contact pad 208
Area). The circular opening 222 with a diameter of 200 μm has 3
1,400 μm ² (about 3 times the exposed area of contact pad 208)
Has an area of. Generally, the area of the terminals and / or substrate where the openings are exposed is preferably between 10,000 and 40,000 μm ² , and most preferably about 30,000 μm ² or more. Although not a key feature of the present invention, as a general matter, the footprint (base end area) of the contact structure provides an area sufficient for mechanically fixing (adhering) the contact structure to an electronic component. Must.

For openings 222, they taper (Figure 5D
(See below for details with respect to FIG. 5F), and the dimensions at the bottom of the tapered opening are
It is preferably on the order of 200 μm × 200 μm, and on the order of 200 μm in diameter for circular openings. In applications where space is constrained and these dimensions are not possible, the available space can be used. For example, center distance 125μ
When handling an electronic component having a pad of 100 μm × 100 μm in m, the opening 222 is 105 μm × 105 μm, 110 μm × 110 μm
Can have dimensions of the order such as. Alternatively, in space constrained applications, the proximal ends of the contact structures can be located away from the pads to which they are electrically connected (discussed below), and are preferably larger (eg, 200 μm). It can be dimensioned. Opening 222
The taper (slope) area of the is indicated by reference numeral 223 in FIG. 2B.

Mask layer 220 is preferably disposed at a thickness of at least about 50 μm, including at least about 100 μm, at least about 150 μm, and at least about 200 μm. The mask layer 220 can be arranged as multiple layers. Basically, the overall thickness of this mask layer 220 determines the distance that the main body of the contact structure is separated from the surface of the electronic component. The proximal end 262 of the spring contact element 260 shown in FIG. 2L.
See main body section 266 offset distance from “d2”. Compare FIG. 3A of the parent application mentioned above.

The sidewalls (end walls) of the opening 222 are such that the opening is larger at the surface of the mask layer 220 than at the portion of the conductive layer 210.
It is preferable to have a taper. This is called a "positive" taper. There is no taper on the steep side wall with an angle of 90 °. Preferably, the sidewalls of the openings have an average taper angle of about 60-75 °. This can be easily achieved by using a photoresist as the material of the mask layer 220 and baking and reflowing the photoresist. Those of ordinary skill in the art with which the present invention is best suited will readily understand how to control the sidewall taper based on the description provided herein. It is within the scope of the present invention that the tapered openings may be formed in any suitable manner, and may be formed substantially stepwise, such as a truncated pyramid with an inverted brim. Mask layer 220
Controlling the shape of the opening 222 within is discussed in detail below.

FIG. 2C is a top plan view of the electronic component 200 of FIG. 2B showing two openings 222a and 222b in the mask layer 220. Each of these openings is associated with one of the two contact pads 208a and 208b (shown in dotted lines). The tapered regions of openings 222a and 222b are designated in this figure by reference numerals 223a and 223b, respectively.

In the next step of this process, as shown in FIG. 2D, for each selected plurality of openings 222, a protruding feature 230 is formed on the surface of the mask layer 220, the center of which is an opening 222.
They may be arranged at a distance "L" from the center of. As will be apparent, this feature 230 is manufactured on an electronic component and the resulting contact structure 260 contacts (tips).
It defines the end 264 and the distance “L” represents the linear distance between the proximal end 262 and the distal end 264 of the contact structure 260 being manufactured on the electronic component. This protruding feature 230 can be a "dot" or "blob" of material, for example exhibiting a crushed hemispherical shape, possibly a small amount of epoxy resin, photoresist or the like, via a stencil or present. It can be appropriately applied by using the conventional screen printing technique. Protruding feature 230
Can also consist of a conductive material. Suitable dimensions for protruding features 230 having the shape of crushed hemispherical dots are approximately 5-15 mils (125-375 μm) in diameter and approximately 2 mils (50 μm) high. It is within the scope of the invention to make the overhanging feature thinner (eg, less than about 5 mils wide) or wider (eg, greater than about 15 mils wide). However, preferably for most applications
It is desirable that the height be within the range of about 2.0-7.5 mils.

Other shapes for protruding features, or more broadly, contact structures manufactured, as described in more detail below.
Various shapes for the tip 264 obtained for 260 include pyramidal, conical or hemispherical, and truncated pyramid, conical or hemispherical, as well as crosses, annulars, etc. It is within the scope of the invention.

Those of ordinary skill in the art with whom the present invention is best suited may be made based on the description provided herein.
It will be easy to understand how to apply and control 0. For example, to create a protruding feature 230 using photoresist and a stencil (not shown), position the stencil and gently bake the photoresist to disengage the protruding feature from the stencil, then harden after removing the stencil. Can be baked and hardened.

The distance "L" between the proximal end 262 and the distal end 264 of the resulting microelectronic spring contact structure is, for example, in the range of about 10-1000 mils, preferably in the range of 10-50 mils. .

As shown in FIG. 2E, the next step in the process is to apply stencil (shadow mask) 240 to mask layer 2
Can be placed on 20 surfaces. The stencil 240 has a plurality of openings 242 (one of many shown). As shown, the opening 242 extends from the opening 222 to a corresponding protruding feature 230. Stencil 240 may preferably be a thin (eg, 2 mil thick) stainless steel foil, which may be punched or etched to have openings 242. Stencil 240 can be made of any material of any suitable thickness provided that seed layer 250 can be deposited on mask material 220 with a pattern of conductive traces corresponding to the shape of openings 242.

With the stencil 240 positioned on the surface of the mask layer 220, a "seed" layer 250 is deposited, such as by sputtering, on the exposed surface of the mask layer 220 and the raised features 230. The seed layer 250 is within the exposed portion of the opening 222,
Deposited on the surface of the conductive layer 210 in this opening 222. The seed layer 250 has a graded region 253, where it is deposited on the graded region 223 of the opening 222 in the mask layer 220.

Seed layer 250 can be deposited as a pattern of multiple "traces," each of which is a physical realization of the pattern of openings 242 in upper stencil 240. The thus patterned seed layer 250 acts as a precursor for the contact structure produced on the electronic component. For example, in an electroplating process, each of the conductive traces of seed layer 250 can act as an electromold, onto which the material of contact structure 260 can be produced.

The choice of mask material 220 and process for deposition of seed layer 250 must be considered together. The mask material is
It should be stable in the environment of the deposition process. For example, a typical positive photoresist material contains some solvent and may evolve gas under high vacuum conditions. In this case, it is preferable to cure the mask material by crosslinking or the like, for example, by baking or exposure to modify the material. Polyimide is a useful mask material and can withstand sputtering environments without substantial degradation. Deposition can also be by chemical vapor deposition (CVD) or electron beam processes. These require less vacuum than in the case of sputtering. For these, conventional novolak photoresist resins can be used, possibly with some mild crosslinking. Another consideration is that any modification to the mask material to make it stable under vacuum can make it difficult to remove later in the process. is there. Appropriate materials and processes can be selected by those skilled in the art. Particularly preferred 1
One process is to use a novolac photoresist resin, patterning as described above, then partially crosslinked by heating. The deposition of seed layer 250 is C
Performed using VD.

FIG. 2F shows in top view the result of the steps described in FIG. 2E, showing two openings 242a and 242 in stencil 240.
b is shown. Each of these openings 242a and 242b is
Two protruding features 230a from the top of each of the two associated contact pads 208a and 208b (shown in dotted lines).
And 230b (indicated by dotted lines) to each selected one.

FIG. 2F also shows openings 242a and 242b in stencil 240.
Figure 2 shows two patterned traces 250a and 250b of the seed layer deposited via. Although these traces 250a and 250b are shown with diagonal hatching for clarity of illustration, it should be clearly understood that this hatching does not show a cross section in this figure.

Each of the traces 250a and 25b shown in FIG.2F includes a contact structure 260 built on the conductive traces 250a and 250b.
Corresponding to the base end portion 262, the tip end portion 264, and the central body portion 266 of the base end portion 252a and 252b and the tip end portion 254a and 25,
4b and central body portions 256a and 256b, respectively. This figure shows the sloped regions of each of traces 250a and 250b.
253a and 253b are shown.

FIG. 2G illustrates the next step in the process where the shadow mask 240 has been removed and a plurality of (one of many) contact structures 260 have been formed, such as by plating (eg, electroplating). However, there are multiple (1 of many
It is constructed as a mass of conductive material on a trace 250 (shown as one). Each of the contact structures 260 includes a proximal portion 262 (compare parent application 302), a distal portion 264 (compare parent application 304), and a main portion extending between proximal portion 262 and distal portion 264. A body 266 (compare parent application 306). As shown, the contact structure 260 has a proximal end 262 and a main body 266.
Has a sloping region 263 between, and the sloping region 263 is a seed layer.
Built on 250 sloped areas 253, but with seed layer 250
Are also constructed on the sloped regions 223 of the openings 222 in the mask material 220.

2H is a cross-sectional view of the electronic component 200 of FIG. 2G taken along line 2H-2H, showing the contour (transverse cross-section) of the contact structure 260 made in accordance with one preferred embodiment of the present invention. This contour is approximately semi-circular or mushroom-shaped. This cross section taken through the main body 266 is a representative contour for the entire length of the contact structure. This structure is the result of electroplating on an exposed seed layer that is substantially flat.

As best seen in Figure 2G (see also Figure 2M),
The resulting contact structure 260 total height "H", in other words substrate 2
The height of the tip 264 away from the surface of 02 is preferably at least about 4.0 mils, and perhaps about 8.0 mils or more.

As best seen in FIG. 2H, the contact structure 260 itself, or in other words the mass “t” of conductive material on the trace 250, is preferably at least about 0.5 mils, and perhaps about 1.5 mils. Mill or more.

As best seen in FIG. 2H, the contact structure 260 itself, or in other words the width “w” of the mass of conductive material on the trace 250, is preferably at least about 0.5 mils,
Probably about 4.0 mils or more. This width may be constant along the main body portion 266, or the main body portion may be narrow, such as wide near the proximal end 262 and narrow near the distal end 264 of the main body 266. It may be.

As described above, the obtained microminiature electronic contact structure is obtained.
The length "L" between the proximal 262 and distal 264 portions of 260 is preferably at least about 10 mils, and perhaps up to about 50 mils or more.

The usual requirements for spring-shaped designs are generally known in the art. Details such as dimensions, bending moments, shapes that allow flexing in various dimensions, and the like are selectable by the designer and can be implemented in accordance with the teachings of the present invention. One particularly preferred shape approximates an annular segment with tapered inner and outer curvatures. Such a shape is shown in FIG.

2I and 2J are perspective views showing two of the many possible configurations for the contact structure 260 of FIG. 2G,
It has been removed from member 200 for clarity of illustration.
These drawings show two important modifications that can be selected using the present invention. In FIG. 2I, the contact structure has a square proximal end 262. In FIG. 2J, the contact structure has a circular (annular) proximal end 262. In any of these drawings, the funnel shape of the proximal end in the sloped region 263 can be easily recognized, which shape is the sloped sidewall 22 of the opening 222 in the mask layer 220.
It is given to the base end by 3. In FIG. 2J, the beveled region 263 of the proximal end 262 is completely (360 °) covered with a slight “lip” extending around the entire circumference of the proximal end. This perfect funnel shape can be easily obtained by using a stencil 440 that allows the seed layer to be deposited along all sidewalls and a portion of the surface of the mask layer 420. Such a stencil is shown in Figure 4E and the resulting structure is shown in Figure 4G. Figure 2I shows the opening 22
2 shows the result of depositing a seed layer on only part of the side wall of 2. This can be easily obtained by using a stencil that covers a portion of the opening 222, as shown in FIG. 2E. More or less sidewalls can be coated, depending on the mask and deposition conditions selected. Included in this is only a portion of one sidewall, all one side as shown in FIG. 2I, more than one side (preferred embodiment), or as shown in FIG. 2J. Such that a complete funnel is formed by all of the lateral areas (a particularly preferred embodiment). The resulting structure after plating is shown in cross section in Figure 2G. If the proximal end is rectangular, a perspective view of Figure 2G would be similar to Figure 2I.

For convenience of illustration, the top plan views 2F and 2K are shown in FIG. 2E and FIG.
2G and 2L show a complete funnel embodiment, replacing the partially funnel embodiment of the detailed cross-sectional views of FIG. 2L. Those skilled in the art can slightly modify FIGS. 2F and 2K to obtain FIGS. 2E and 2G.
And that it may correspond to the specific embodiment of FIG. 2L. The resulting structure will resemble a partial funnel as shown in Figure 2I with a circular base as shown in Figure 2J.

2K is a top plan view of electronic component 200 of FIG. 2G showing two of the plurality of contact structures 260a and 260b. Each contact structure 260a and 260b is associated with one of two contact pads 208a and 208b (shown in dotted lines). Each of the contact structures 260a and 260b has a proximal end 262a and 262b, a distal end 264a and 264b, and a central body 266a and 266b, respectively. The sloped regions 263a and 263b of the contact structures 260a and 260b are shown in this figure, respectively.

As can be seen in FIG.2K, the resulting contact structure is in the same manner as the tapered contact structure illustrated and described in the parent application described above, from wide at the proximal ends 262a and 262b respectively to the distal end 264a and Properly taper (with respect to width) to narrow at 264b. Contact structure 260a and
Although 260b is shown with cross hatching for clarity of illustration, it should be clearly understood that this cross hatch is not a cross section in this figure.

As is apparent from the illustration of FIG. 2G, the proximal end 262, and thus the entire contact structure 260, is associated with the contact pad 208 of the electronic component via the seed layer 250 and the conductive layer 210.
Electrically connected to one another, as is also apparent from the foregoing description, a group of contact pads 208 of electronic components can be shorted together by a conductive layer 210,
Thereby the contact structure 260 by electroplating process
Is easy to build.

In the final processing step of the process, the mask layer 220 can be removed, for example by washing off with a suitable solvent. For example, the photoresist mask layer 220 is
It can be selectively washed off with acetone without adversely affecting any of the other factors mentioned above. And finally, all portions of conductive layer 210 that are not covered by another material (ie, by seed layer 250) can be selectively etched away using suitable chemical means.

2L and 2M show the free-standing contact structure 260, which is the final product, in cross-sectional view and perspective view, respectively. It is attached to the electronic component at its proximal end 262, the main body 266 is located away from the surface of the electronic component 202, and its tip 264 projects further than the level of the main body 266. It has a shape. The resulting contact structure 26
The inclined region 263 of the base end portion 262 of 0 can be clearly seen from these drawings and can also be clearly seen in FIGS. 2N and 2O described later.

Basically, for each of the contact structures 260, an elongated mass of conductive material is provided on the mask material, the proximal end 262, the distal end 264 opposite the proximal end 262, and the proximal ends 262 thereof. And having a main body portion 266 between a tip portion 264 and
There, the main body 266 lies in a plane that is preferably substantially parallel to the surface of the substrate 202 and offset (in the z-axis direction) from the proximal end 262. As a result of having the protruding feature 230, the tip 264 is further offset from the main body 266.
When the mask material 220 is removed, the resulting contact structure 260 is self-supporting and is secured to the substrate 202 by its proximal end 262 and its distal end 264 is another electronic component (see below). , For example, 272 or 282, respectively) and (eg, 270 or 280) terminals are freely contacted.

Materials and Processes Similar to the parent application approach, the contact structures of the present invention are primarily, preferably wholly metallic, and may be formed (manufactured) as a multilayer structure. Suitable materials for one or more layers of the contact structure mass include, but are not limited to:

  Nickel and its alloys.

  Copper, cobalt, iron and their alloys.

Gold (especially hard gold) and silver. All of these show excellent current carrying ability and good contact resistance characteristics.

  Platinum family element.

  Precious metal.

Semi-precious metals and their alloys, especially elements of the palladium group and their alloys.

Tungsten, molybdenum and other refractory metals and their alloys. The use of nickel and nickel alloys is particularly preferred.

Tin, lead, bismuth, indium, and alloys thereof can also be used if a solder-like finish is desired.

Preferred processes for depositing materials for the conductive layer 210, seed layer 250 and contact structure 260 include various processes involving deposition of materials from an aqueous solution, electroplating, electroless plating, chemical vapor deposition (CVD). , But not limited to, physical vapor deposition (PVD), processes that cause deposition of materials through the induced disintegration of liquid or solid precursors, and the like. All these techniques for depositing materials are generally well known.

A suitable material for the conductive layer 210 is titanium-tungsten (T
i-W), which is 300-
It can be deposited to a thickness of 600 nm, for example 450 nm. Although optional, it is preferred to add a layer of gold to the conductive layer 210, which has a thickness of 250-450 nm, for example 350 nm.
Can be deposited to a thickness of. The purpose of the conductive layer 210 is primarily to use an electroplating process to build the mass of conductive material that will eventually become the contact structure 260 on the seed layer.
To provide an electrical connection to the conductive traces 250. However, it is within the scope of the invention to omit the conductive layer 210. Other processes, such as electroless plating, can be used to build up the mass of conductive material that will eventually become the contact structure.

The seed layer 250 may be made of gold (Au), for example,
It can be deposited by sputtering to a thickness of about 250-400 nm. In another preferred embodiment, the seed layer is copper (Cu), which is sputtered
It can be deposited to a thickness of 0-300 nm. Alternatively, the seed layer 250 can be composed of another suitable material on which the final contact structure 260 mass can be built.

Suitable materials for the mask layers 220, 320, 420 include various lithographic photoresists, novolac resins, and polyimides.

Compliant and Elastic Figure 2N shows the tip 264 of the contact structure 260 and the contact pad 27 of another electronic component 272, such as a printed circuit board (PCB).
The case where it is desirable to make a connection by pressure contact with 0 is illustrated. In this case, the contact structure 260 is the substrate 2
It must react elastically (ie elastically rather than plastically) along the "z-axis" (90 °) perpendicular to the surface of 02. This is the case, for example, when it is desirable to make a socketable, easily removable connection between the substrate 202 and the electronic component 272.

FIG. 2O shows the tip 264 of the contact structure 260 soldered to a contact pad 280 (compare 270) of another electronic component 282 (compare 272) such as a printed circuit board (PCB).
By way of example 4, the case where more permanent joining is desired is illustrated. In this case, the contact structure 260 must react compliantly along the “z axis” and / or the “y axis” parallel to the surface of the substrate 202. This is for example
It is when it is desirable to address the difference in coefficient of thermal expansion between two electronic components.

It is within the scope of the invention for the contact structure 260 to respond to an applied force by elastically and / or compliantly flexing along any or all of the x, y, and z axes. is there.

Such elastic contact structures can be reinforced by the addition of additional members. `` Contact Tip Structures f
or Microelectronic Interconnection Elements and me
Co-pending U.S. Patent Application Nos. 08 / 819,464, and 19 entitled "thods of Making Same"
Correspondence published as WO97 / 43653 on November 20, 1997
PCT Patent Application No. PCT / US97 / 08606 describes a method of defining a tip structure on a sacrificial substrate and transferring this structure to an electronic component. This tip structure can be transferred to the structure of FIG. 2L using the techniques described in this application.

Another Exemplary Contact Structure A useful feature of the contact structure 260 of the present invention is that the tip 264 is offset from the main body 266. This offset is a consequence of the presence of protruding feature 230. Note the offset distance “d1” of the tip 264 from the main body 266 of the spring contact element 260 shown in FIG. 2L. Compare with Figure 3A of the aforementioned parent application.

However, in some applications it is possible that such offset of the tip from the main body of the contact structure is not required.

According to one embodiment of the invention, the main body of the contact structure extends to the tip of the contact structure, but the tip is not offset from the main body. For example, the tip can be substantially flush with the main body. The process for manufacturing such contact structures proceeds generally in the manner previously described with respect to FIGS. 2A-2L with the following changes.

FIG. 3A (compare FIG. 2D) shows a passivation layer 304.
A conductive layer on a substrate 302 (compare 202) having contact pads 308 (compare 208) exposed through openings 306 (compare 206) provided in (compare 204).
An opening 322 (222) provided above the 310 (compare 210)
(Compare with) and mask layer 320 (compare 220). A protruding feature 230, as distinguished from FIG. 2D.
Is not provided. Similar to what has been described above with respect to FIG. 2B, the tapered region of opening 322 is designated in this figure by reference numeral 323.

FIG. 3B (compare FIG. 2E) also illustrates a stencil (shadow mask) 340 (compare 240) that is placed over the mask layer 320, which stencil 340 compares with aperture 342 (242). The seed layer through which
350 (compare 250) over the mask layer 320, opening 310 and
Deposited inside 306 as well as on contact pad 308. Since no protruding features 230 are provided in this example, the seed layer 350 is not bumped up towards the tip of the final contact structure, but the final contact structure does not. It can be seen that it is essentially aligned (coplanar) with the part that should be the main body. The seed layer 350 has a graded region 353, where it is deposited on the graded region 323 of the opening 322 in the mask material 320.

Subsequent processing steps include deposition of the material forming contact structure 360, removal of mask layer 320, and removal of exposed (uncovered) portions of conductive layer 310 as described in the previous embodiments. Proceed to. FIG. 3C (compare FIG. 2K) shows the above-described plating, washing away of the mask layer 320,
And contact structure 360 (2) resulting from such a process after selective etching of a portion of conductive layer 310.
(Compare 60). The resulting contact structure 36
The 0 has a proximal portion 362 (compare 262), a distal portion 364 (compare 264), and a main body portion 366 (compare 266). As shown, this contact structure 360 has its proximal end 362.
And a main body portion 366 having an inclined region 363. Inclined area 36
3 is on the inclined region 353 side of the seed layer 350, which is also on the inclined region 323 of the opening 322 in the mask layer 320.

This structure can be further processed with the addition of additional components to form more complex structures. "Cont
act Tip Structures for Microelectronic Interconnec
Action Elements and methods of Making Same ",
Co-pending US patent application owned by the applicant
08 / 819,464, and its corresponding PCT patent application No. PCT / US97 / 08606, published as WO97 / 43653 on Nov. 20, 1997, define a tip structure on a sacrificial substrate, which is used as an electronic component. Describes how to transfer to. This tip structure is
The techniques described in this application can be used to transfer to the structure of Figure 3C.

Another useful enhancement to this structure may be to include a spacer element so that the added tip element projects further from the main body portion 366. Filed on January 29, 1998, "MICROELECTRONIC CONTACT STRUCTURES, A
Co-pending US Patent Application No. 08 / (Not Granted) owned by the applicant entitled "ND METHODS OF MAKING SAME"
The issue describes making a post structure, making a tip structure, and joining the two together to a support structure. This works well for the elastic contact structure of FIG. 3C, resulting in an elastic contact structure with a precisely defined tip structure. In one preferred embodiment, a tip-post combination made as described in the co-pending U.S. patent application just mentioned is brazed to the tip of the main body portion 366 and the tip-post combination is The combination with the post is released as described in this co-pending US patent application. Referring to FIG. 3D, tip 364 is secured to post 382 by brazing material 381, which is secured to tip body 384 by brazing material 383. Although the tip body 384 is shown with the preferred tip 385, this feature is optional.

Remote Placement of Contact Structures Above, a technique for making contact structure 260 having a proximal end 262 provided substantially directly at a contact pad 208 of an electronic component such as a semiconductor device has been described. In some applications of electronic components, contact structures,
In particular, it is desirable to place its base end away from the contact pad to which it is connected. In this way, the tips 264 of the contact structures 260 can have a different layout (pattern, pitch, etc.) than the contact pads to which they are connected.

The aforementioned US patent application Ser. No. 08 / 955,001 discloses manufacturing a spring contact element on an electronic component in a region remote from the terminal (contact pad) to which it is coupled (to which it is electrically connected). ing. Generally, the spring contact element can be mounted on a conductive line extending from a terminal (contact pad) of an electronic component to a position away from the terminal. Thus, a plurality of substantially identical spring contact elements are mounted on an electronic component such that their free (end) ends are arranged in a pattern and position that is independent of the pattern of the terminals on the electronic component. It is possible. In a particularly useful embodiment, the free ends of the spring contact terminals may be spatially displaced from the terminals to which they are electrically connected.

The concept of placing the spring contact elements away from the terminals of the electronic component can be incorporated into the technology of the present invention, and the microelectronic contact structure of the present invention allows them to be coupled (electrically connected) together. It can be manufactured at a position away from the terminals.

FIG. 4A is comparable to FIG. 2A and shows an exemplary electronic component 400 (compare 200) on which a plurality of contact structures can be manufactured. Although the fabrication of a single contact structure 460 (compare 260) is described, this is an example of the fabrication of multiple such contact structures, preferably all on the same member at the same time. Typically, each of the contact structures manufactured on a single member are substantially identical (ie, size, shape, etc.) to each other, but depending on the requirements of a given application, the designer It is within the scope of the present invention that can individually control and determine the size and shape of each contact structure.

In this embodiment as well, as in the previous embodiment, the electronic component 400 is a semiconductor device, a silicon substrate 402 (compare 202), and a passivation layer 404 (compare to the surface of the silicon substrate 402). (Compare 204) and an opening extending through the passivation layer 404 to the metal contact pad 408 (compare 208).
It consists of 406 (compare 206).

As in the previously described embodiment, as shown in FIG.
2A), the first step in this process is
A conductive layer 410 (compare 210) is deposited. It is deposited as a continuous layer of identical shape of titanium-tungsten (Ti-W) with a thickness of about 450 nm by sputtering, and is deposited on the surface of the passivation layer 404, the sidewalls of the opening 406 and the metal contact pad 408. Cover the exposed (inside the opening) surface.

In contrast to the previously described embodiment, in this embodiment a second conductive layer 412 is deposited and patterned on the conductive layer 410 to provide a location 422 from a location on the contact pad 408 that is remote from the contact pad 408. It is possible to cover an area extending to. Deposition and patterning of the second conductive layer 412 can be done by conventional semiconductor processing techniques, including but not limited to:

(A) Deposit second conductive layer 412 as a blanket layer and then pattern (eg, using conventional photolithographic techniques).

(B) Deposit a second conductive layer 412 as a patterned layer using a stencil, such as stencil 240 described above. Alternatively, (c) the second conductive layer 412 is deposited as a blanket layer to cover all, or possibly some areas of the conductive layer 410. This second conductive layer 412 can be patterned in a subsequent step using, for example, the techniques described in the aforementioned US patent application Ser. No. 08 / 955,001.

The second conductive layer 412 is preferably 250-450 nm thick, eg 3
It is a 50 nm thick layer of gold (Au). The design and specific dimensions of this second conductive layer 412 can largely correspond to conventional traces, and one of ordinary skill in the art can easily select an appropriate dimension.

Various techniques for providing the patterned second conductive layer 412 are described in the aforementioned US patent application Ser. No. 08 / 955,001, which is hereby incorporated by reference.

As shown in FIG. 4B (compared to FIG. 2B), in the next step of the process, a layer 420 of mask material (eg, photoresist) is placed on the surface of the silicon substrate 402 (ie, conductive layer 410 and first layer). Second conductive layer 412) and an opening 422 (compare 222) extending through the mask layer 420.
Patterned (eg, using conventional photolithographic techniques). In this example, the opening 422
Are not above the opening 406 provided in the passivation layer 404 (as described with respect to the previous embodiments), but are located away from the opening 406 and thus from the contact pad 408. By locating multiple such openings 422 away from contact pads 408,
A plurality of substantially identical contact structures 460 on the electronic component,
The electronic component can be manufactured with a layout different from the layout of the contact pad.

As in the previous embodiment, in this embodiment each opening 422 is preferably an opening on contact pad 408.
It has a larger area than the area of 406. For example opening 422
May have an area of 40,000 μm ² (4 times the exposed area of contact pad 408). Even in this case, as a general matter, which is not the key feature of the present invention, the footprint (base end area) of the contact structure is due to mechanical fixation (adhesion) of the contact structure to the electronic component. Must be large enough (under given spatial constraints).

As in the previous embodiments, in this embodiment mask layer 420 is preferably deposited to a thickness of at least about 50 μm, including at least about 100 μm, at least about 150 μm, and at least about 200 μm. As in the previous embodiment, in this embodiment the side wall (end wall) of the opening 422 is preferably positively tapered. Similar to that described above with respect to FIG. 2B, the beveled region of aperture 422 is designated in this figure by reference numeral 423.

FIG. 4C (compared to FIG. 2C) is a top plan view of electronic component 400 of FIG. 4B, showing opening 422 in mask layer 420 and associated contact pad 408 (shown in dotted lines). In this figure, the patterned portion of the second conductive layer 412 is also shown in dashed lines and extends from the contact pad 408 into the opening 422. In a manner similar to that described above with respect to FIG. 2C, the beveled area of aperture 422 is designated in this figure by reference numeral 423.

In this example, in the next step of the process, as shown in FIG. 4D (compared to FIG. 2D), the protruding feature 43 is similar to the technique in the previous embodiment.
0 on the surface of the mask layer 420, the distance “L '” from the opening 422.
They can be placed at (comparable to the distance "L"). As in the previous embodiment, this embodiment has a protruding feature.
430 defines the basic geometry of the contact (tip) end 464 of the final contact structure 460 being manufactured on the electronic component 400. As in the previous embodiments, in this exemplary embodiment the protruding features 430 are "dots" or "nodules" made of materials such as epoxy resin, photoresist and the like.
Is.

As in the previous embodiment, in this embodiment FIG.
In the next step of this process, as shown in
A stencil (shadow mask) 440 (compare 240) is deposited on the surface of mask layer 420 and has openings 442 (compare 242). With the stencil 440 positioned on the surface of the mask layer 420, a “seed” layer 450 (comprising gold, for example) is deposited on the exposed (via openings 422) surface of the mask layer 420 and on the raised features 430. (Eg by sputtering). This deposition includes within the openings 422 in the mask layer 420 and on the exposed surface of the second conductive layer 412. This patterned partial seed layer 450 forms a contact structure 460 fabricated on the electronic component 400.
Can be thought of as a "trace" that serves as the basis for defining The seed layer 450 has a sloped region 453,
There, it is deposited on the inclined regions 423 of the openings 422 provided in the mask material 420.

FIG. 4F (comparable to FIG. 2F) is a top plan view of electronic component 400 of FIG. 4E, showing opening 422 provided in stencil 440. This opening 422 projects from a position (opening 422) away from the contact pad 408 (shown in dotted lines).
It extends to (indicated by the dotted line).

FIG. 4F also shows patterned traces of seed layer 450 deposited through openings 422 in stencil 440. Although this trace is shown with diagonal hatching for clarity of illustration, it should be clearly understood that this hatching does not show a cross section in this figure. The trace has a proximal end 452, a distal end 454, and a central body 456.

FIG. 4G (comparable to FIG. 2G) shows the results after the next step in this process, where contact structure 460 is shown.
(Compare 260) is constructed on the conductive traces of seed layer 450. The contact structure 460 includes a proximal end 462 (compare 262), a distal end 464 (compare 264), and a proximal end 46.
2 and a main body portion 466 (compare 266) extending between the tip portion 464. As shown, the contact structure 460 has a beveled region 463 between its proximal end 462 and main body 466. The graded region 463 is on the graded region 453 of the seed layer 450, which is also the graded region of the opening 422 in the mask material 420.
It's on 423. Contact structure 46 taken through main body 466
The cross-sectional view of 0 looks similar to the cross-sectional view of the contact structure 260 shown in FIG.

On most sides, the contact structure 460 is the contact structure 260.
Can be identical to the
462 is located away from the contact pads 408 with which it is mated. In other words, contact structure 460, like contact structure 260, can be of various geometries, dimensions and materials within the same range.

Similar to the previous example (compare FIG. 2K), for any of the other factors mentioned above, such as by washing off with a suitable solvent in the final treatment step of the process of this example. The mask layer 420 can be removed without adversely affecting it. And finally, all portions of conductive layer 410 that are not covered by another material (second conductive layer 412 in this example) can be selectively etched away using suitable chemical means. . The resulting end product is a freestanding contact structure 460 that is attached at its proximal end 462 to the electronic component 400 at a location remote from the contact pads 408 to which it is electrically connected. , Its main body portion 466 is arranged away from the surface of the electronic component 400, and its tip portion 464 has its main body portion 4
It has a shape that is located further than 66 levels.

As in the previous embodiment, the contact structure of this embodiment can be manufactured without first depositing the dots 430 on the mask layer, so that the tip is aligned with the main body. Contact structure (compare 360)
Is obtained. However, again, the proximal end of such a contact structure is located away from the contact pad to which it is electrically connected by the second conductive layer 412.

The various contact structures described above (eg 260, 360, 46
It is within the scope of the invention that 0) can be implemented on a single electronic component in any combination.

Routing and Spatial DeformationFor remotely located contact structures 460, various complex routing schemes may be implemented in a manner as discussed by the aforementioned US patent application Ser. No. 08 / 955,001. it can.

In other words, a technique for manufacturing a microminiature electronic contact structure on an electronic component is described, the electronic component being a “spatial deformation” from a contact pad (terminal) of the electronic component on which the contact structure is mounted. Bring in. As used herein, the term "spatial deformation" means that the tip (end) ends of the contact structures are arranged at a different pitch (pitch) and / or orientation than that of the terminals of the electronic component to which they are electrically connected. Means

In this way, the plurality of contact structures are mounted on the electronic component, and the layout and / or pitch of the contact structure is different from that of the terminals of the electronic component with respect to the corresponding plurality of terminals on the electronic component. Can be electrically connected in any way. For example, the terminals of the electronic component are arranged at a first pitch in a pattern forming a peripheral row, and the tip of the contact structure is arranged at a second pitch
It is possible to arrange them in the form of a region array with the pitch of ∘ and vice versa.

Preferably, for a plurality of contact structures on an electronic component, each of the contact structures is manufactured substantially similar (same) to one another. One advantage of using similar structures is that the mechanical and elastic properties of the structures can be similar. Spatial deformation can be performed by processing steps that have minimal impact on the manufacture of the contact structure.

The conductive traces of the second conductive layer 412 that achieve the spatial deformation provide the basis for contact structures along the surface of the electronic component to achieve a "simple" spatial deformation, such as fan-out (or fan-in). It can be stretched linearly (linearly) to the edges. Alternatively, the conductive traces that achieve spatial deformation can be routed along the surface of the electronic component, including intersecting with each other to achieve more complex spatial deformation schemes if desired.

An advantage of the present invention is that the contact layout of an existing electronic component can be modified after the electronic component has already been completely created. For example, finished (finished)
The semiconductor device has a number of bond pad terminals accessible from its surface through openings in the passivation layer. If multiple identical contact structures are mounted or manufactured on these terminals, the tips of those contact structures will "mirror" the layout of the bonding pad. The present invention essentially "repositions" these terminals (at least a portion thereof) and allows the tips of the contact structures to have a layout that is quite different from the bonding pads of the semiconductor device.

Tapering the openings in the mask layers As discussed above, the openings 222,322,422 in the mask layers 220,320,420 are preferably tapered. Tapered openings can be implemented in many ways.

5A and 5B illustrate prior art techniques for creating openings 502 through a layer 504 of mask material on a substrate 506. The mask layer 504 can be a photosensitive material such as photoresist. A photolithography mask 508 is disposed on the mask layer 504. This mask 5
08 is preferably transparent (transmissive) to the light from actinic radiation source 510. The mask 508 has a pattern of opaque material 512 (eg, iron oxide or chrome) 512 on its surface.

Typically, the mask 508 is placed as close as possible to the mask material 504, such that it exhibits similarities to "contact printing" in the photographic industry.

In areas 514 where there is no opaque material 512 on the surface of mask 508, light from source 510 can pass through mask 508 to mask material 504. In areas where there is opaque material 512 on the surface of mask 508, light from source 510 cannot pass through mask 508 and onto mask material 504. Thus, the "non-exposed" areas 522 of the mask material 504 below the opaque material 512 are shielded from light and the mask material 50 below the non-opaque areas 514 of the mask 508 without the opaque material 512.
The four "exposed" areas 524 are exposed to light. Generally, a mask
Regions 524 of mask material 504 exposed to light passing through 508
Are "developed" and areas 522 of mask material 504 that are shielded from light passing through mask 508 are not "developed". This illustrates a "positive" type photoresist, as the remaining mask material replicates the pattern of opaque material on the mask. Upon completion of the exposure, depending on whether the mask material 504 is "positive" or "negative," either the area 522 or the area 524 is selectively washed away (removed) with a suitable solvent, such as acetone. be able to.

As best seen in Figure 5B, the developed areas 524 of the mask material 504 have been washed away upon completion of the exposure.

FIG. 5C illustrates an alternative prior art technique for creating openings 502 through a layer of mask material 504 ′ (compare 504) on a substrate 506. A photolithographic mask 508 is placed on the mask layer 504 'and has a pattern of opaque material 514' (compare 512) on its surface.
In this example, the opaque material 514 'is the area 52 of the mask material 504'.
It is on 4'and it is desired to create an opening 502 therein. Remaining areas 512 'of mask 508 (compare 514) are not covered with opaque material and light from source 510 passes through these areas to areas 522' underlying mask material 504 '. Can be reached. In this example, region 522 'is exposed to light and "developed" and region 524' is not exposed to light. Thus, the area 524 'can be washed away upon completion of the exposure, resulting in the desired opening 50 in the layer of mask material 504'.
You get 2. This exemplifies a "negative" type photoresist because the remaining mask material is the exact opposite of the pattern of opaque material on the mask.

As is known, for a given mask material (including "positive" and "negative" photoresist materials),
There is an optimum exposure intensity and exposure time that ensures that a particular area of mask material 504 (eg 524) is fully developed. As best seen in FIG. 5B, such techniques can result in very steep sidewalls for the resulting openings 502 in the mask material 504. For most existing applications, steep sidewall openings are considered highly desirable.

As mentioned above, the openings 222, 32 in the mask layer of the present invention.
The 2,422 side walls (end walls) are preferably tapered and have a "positive" taper, such as in the range 60-75 °. The possibility of using photoresist for the material of the mask layers 220, 320, 420 and starting from an opening with steep sidewalls (see, eg, FIG. 5B) and then gently reflowing the photoresist to taper the sidewalls was described above.

According to one aspect of the invention, tapered sidewalls in the openings in the mask material can be achieved, for example by:

(A) Gently reflow the mask material to taper the sidewalls of the opening. Or (b) controlling the exposure intensity and / or time. Or (c) changing the distance of the mask from the mask layer during exposure (essentially defocusing the mask during exposure). Or (d) exposing the mask layer twice or more, once with a mask having smaller transparent areas (eg 514) and another with a larger transparent area (essentially stepped) And the opening). The stepped mask layer can be optionally reflowed to smooth the steps. Or (e) the openings that overlap each of the multiple mask layers are formed so that each is sequentially larger (or smaller) than the opening of the previous mask layer. In this case also, a stepped mask layer is obtained. This can optionally be reflowed to smooth one or more steps, or (f) a combination of (ae) above.

The explanation of (a) to (e) below is based on the above-mentioned example (a).
It is a development of each of (e) to (e).

(A) Reflow taper mask material 5 on substrate 536 as shown in FIG. 5D.
Starting with a traditional opening 532 in 34 layers, ie opening 532 showing steep sidewalls (compare FIG. 5B), in a pre-finishing step the mask material 534 is heated and / or diluted in a controlled manner. It can be immersed in a solvent. This allows the angle of the steep sidewalls of the opening to be "blunted", resulting in a gentle (as shown) surface from the base (at the surface of substrate 536) to the top (as shown) surface of mask material 534. For example, an opening 538 (compare 222, 322, 422) that is curved (tapered) as shown is obtained. Obviously, however, the area of the base of the opening is reduced. Therefore, the first opening in the mask material should be oversized accordingly so that the base dimension of the final "reflowed" opening is the desired dimension (eg 200 μm diameter). This figure shows openings 538 in mask material 534.
Have tapered regions 539 (compare 223, 323, 423).

(B) Controlled taper of exposure FIG. 5E uses the exemplary technique described with respect to FIG.
Controlling the dose of light (exposure and duration) that passes through the transparent regions 514 of the mask 508 is tapered through the layer of mask material 544 (compare 534) on the substrate 546 (compare 536). 3 illustrates a technique for creating an opening having sidewalls. Generally, the portion of the mask material 544 closest to the surface (top surface, as shown) develops faster than the "deeper" portions of the layer of mask material 544. The fastest developing portion of mask material 544 is therefore the top (as shown) surface of mask material 544 closest to mask 508.
Conversely, the slowest developed portion of mask material 544 is the portion immediately adjacent substrate 546.

Mask material just below transparent area 514 of mask 508
The development of the mask material 544 is limited to the part of the exposure normally required to fully develop the entire surface of the 544, for example, up to half, the development of the mask material 544 on its upper surface (closest to the mask)
To its lower surface (farthest from the mask and closest to the substrate).

In FIG. 5E, the intermediate product is shown, and the portion 548a of the mask material 544 that has been developed is shown by dashed hatching, which can be washed away to provide the desired opening, as described above. This opening will have the same contour as the developed portion of the mask material. The portion 548b of the undeveloped mask material 544 is shown without hatching and defines the sidewalls of the resulting opening (shown in dotted lines) after washing away the developed portion. As in the previous embodiment, the sidewalls of this opening are large at the surface of the mask material and taper from there to a smaller one at the substrate surface, so that the final opening base dimension is the desired dimension (e.g. 200 μm diameter).
m), the first opening in the mask material should be oversized accordingly. This figure shows the mask material 544
The portion 548a which becomes the opening in the taper region 549 (223, 32
(Compare 3,423).

As (f) above, one or more of the tapering techniques (a-e) disclosed herein are combined with one another,
The desired contoured openings can be obtained in the mask material.

(C) Tapering by varying mask distance Another technique for creating openings in the mask layer so that the openings have tapered sidewalls is mask 508 during exposure.
Is to move away from the substrate 506 gradually.
This causes the image of the mask on the surface of the mask material to be defocused, resulting in a situation similar to the intermediate product shown in Figure 5E. By controlling how the distance of the mask to mask material is varied during exposure of the mask material, the resulting aperture can be larger than the transparent portion 514 of the mask 508. Therefore, the first opening in the mask material can be accordingly undersized so that the final opening has a desired base dimension (eg, 200 μm diameter).

(D) Multiple Exposures FIG. 5F shows mask material 554 (544) on substrate 556 (compare 546) using the exemplary technique described with respect to FIG. 5A.
Cf. layers) to create openings with tapered sidewalls. In this embodiment, the first mask is used to substantially completely develop the portion 558a of mask material 554 in the first region having the first width dimension. Mask material in a second region having a second width dimension greater than the first width dimension
A second mask is used to substantially develop only the upper portion 558b (eg, half the thickness) of 554. For example, the first exposure can produce a first region having a diameter of 200 μm and the second exposure can produce a second region having a diameter of 225-250 μm. Preferably, the second
Regions are aligned to overlap the first region, but they need not be concentric.

This results in a mask material 554 having an inverted wedding cake-like stepped opening 558 (compare 538). It is within the scope of the invention that more than two masks can be used, each of them exposing a larger area than the preceding mask, forming an opening with more than one step. The mask material can be reflowed as described above to remove the sharp edges (if any) from the resulting openings 558, or can be treated by other methods to blunt each sidewall. . The figure shows that the openings 558 in the mask material 554 have stepped tapered regions (compare 223, 323, 423) in this case rather than being smooth.

(E) Tapering by the use of multiple layers The techniques (a-d) described above are mainly aimed at creating tapered openings in a single layer of mask material. However, they are also applicable to each of the multiple layers of mask material.

For example, a first layer of mask material can be exposed and then a second mask layer can be applied and exposed on the first mask layer. After both mask layers have been exposed, the mask layers are washed to create openings, which may be exposed areas of the mask material or unexposed areas of the mask material. In some cases.

For example, the final product as shown in FIG. 5F exposes a first layer of mask material to have a first region having a diameter of 200 μm, then applies a second layer of mask material, and Expose a second layer of this mask material to 225-2
It can be manufactured by having a second region with a diameter of 50 μm and cleaning this mask material to have a stepped opening in the manner described above. One or more of these multilayers can be partially exposed as described above with respect to Figure 5E, such that each of the exposed areas taper on itself. Then, in a final pre-finishing step, the sidewalls of the openings formed in the mask material can be "smoothed", for example by reflow, as described above.

With respect to creating openings with tapered sidewalls, it is advantageous, but not necessary, to have smooth (rather than stepped) sidewalls. Also, it is advantageous, but not necessary, for the sidewalls of the opening to have a constant slope or a gradual slope. It may be advantageous to employ multiple stages (eg, upside down wedding cake), especially when there are many relatively low stages. A useful average slope can be defined even if the sidewalls of each individual step (hierarchy) are relatively steep. The purpose here is generally to provide the mechanical benefits of structures constructed with slanted members. A suitably graded mask layer is easily coated (eg, with seed layer 250) without mechanical or electrical discontinuities, which would otherwise be an adventure when the sidewalls of the openings are high and steep. Is.

Tip Geometry The geometry and pattern of the seed layers 250, 350, 450 on which the contact structures (260, 360, 460, respectively) are built up are similar to any desired patterning of the seed layers. , Easily controlled. The proximal ends (respectively 262, 362 and 462) of the contact structures (respectively 260, 360 and 460) can be dimensioned as desired. The main body portions (266, 366, 466, respectively) of the contact structure (260, 360, 460) can be curved rather than straight. The tips (264, 364, 464, respectively) of the contact structures (260, 360, 460, respectively) can have almost any desired shape. The tip portions (264, 364, 464, respectively) illustrated so far have been shown as having a circular contour (in plan view) (see, eg, the top plan view of FIG. 2K and the perspective view of FIG. 2M). this is,
Although described as corresponding to a nearly hemispherical topology, it can easily have a conical or spherical cross section and be truncated depending on the shape of the protruding feature 230 (or 430). You can also

In some applications, the tip 264 of the contact structure is soldered (or brazed) to a terminal 280 of an electronic component 282, such as a printed circuit board, as previously described with respect to FIG. 2O, for example. Is desirable. As is apparent from this illustration, the solder 284 forms a "fillet" that smoothly "flows" between the exposed areas of the pad 280 and the exposed portion of the tip 264 of the contact structure 260. As a general matter,
The larger the area in which the solder can form the fillet, the stronger the solder joint obtained.

Therefore, according to one aspect of the present invention, the seed layer 250,
The geometry of the conductive traces at 350,450 can be adjusted to increase the amount of surface area on the tip obtained on the contact structure due to the formation of fillets.

FIG. 6A shows tip 61 of contact structure 610 (compare 260).
1 of many possible shapes for 4 (compare 264)
Is shown in plan view. In this example, the tip 61
4 is formed as a ring and has a substantially annular outer edge 6
14a, a generally annular inner edge 614b, and a gap 614c extending between the outer and inner edges 614a and 614b. In this way, for a given thickness (not visible in this view, towards the back of the paper), each of the outer and inner edges 614a and 614b is entirely soldered (compare 602). To provide a surface area that can form a fillet. In topology, in one preferred form it has the shape of a slotted disc and is connected to the main body 616 by a beveled portion 613. This sloped portion is comparable to the sloped region 263 (see Figure 2G), but the sloped portion 613 is between the main body and the tip. The disc is generally flat, and a gap 614c is shown. Such discs are formed on a protruding feature (see 230) having the shape of a frusto-cone and the openings provided in the stencil (see 240) define the slotted disc as shown. In the second preferred form, the topology is a slotted hemisphere and is built on a hemispherical protruding feature using a stencil with appropriate openings. In the third preferred configuration, the tip is generally flush with the main body 616.

FIG. 6B shows tip 66 of contact structure 660 (compare 610).
Another of the many possible shapes for 4 (compare 614) is shown in plan view. In this example the tip 664
Is formed as a "cross" within an area (shown by the dotted line) that is comparable to the area of the tip 614. This is another way to supplement the surface area of the tip, and thus the fillet forming area, for a tip of a given size.
In topology, in one preferred form this cross is made from a patterned disc similar to that described above with respect to FIG. 6A. This is the sloping part
Includes a sloped portion 663 comparable to 613. In another preferred embodiment, the cruciform is simply an extension of the main body portion 666 of the contact structure 660 and is generally flush therewith. In yet another embodiment, the cruciform is formed by suitable masking of hemispherical protruding features (see 230).

In the top plan views of FIGS. 6A and 6B, the contact structure 61
Emphasis is placed on increasing the effective wetting area (along the z-axis, ie towards the back of the paper as shown) of the tips 614 and 664, respectively of 0 and 660. The tip has a thickness (toward the back of the sheet in the drawing as shown),
It also has a side profile according to any of the embodiments of the contact structure described above.

As mentioned above, the raised features can be formed using stencils or screen printing. One of the preferred methods for forming a protruding feature is to use a stencil with openings that are arranged with a well-defined shape. Figure 8
Referring to, the stencil 810 has one or more openings 8
Manufactured with 15. These openings 815 can be patterned with high precision to correspond to the desired layout of the protruding features provided on the final product. Each opening
815 can also be shaped to define the desired topology. In this example shown, the aperture is tapered, which is useful for frusto-conical or frusto-pyramidal cross sections. Other shapes can be defined as desired.

The opening 815 is substantially filled with material 830 and the stencil is placed on the mask layer (see 220 in FIG. 2D) overlying the electronic component (see 202). One of the preferred materials 830 is a photolithographic resist material that is cured to have the desired mechanical and chemical properties. The materials for material 830 and mask layer 220 are such that these materials adhere and mask stencil 810 is simply lifted.
It can be selected such that removal from 20 leaves a protruding feature 230. Additional processes such as heating and suitable stripping conditions can be applied as needed. Another preferred stripping mechanism is to push material 830 through opening 815 by posts 825 provided on stripping plate 820. The stencil can still be placed against the mask layer (see 220), so that the material 830 contacts the mask material. Then, for example, post 825 is just material 8
Stencil 8 the release plate 820 by touching 30
Position with respect to 10. Peeling stencil plate 82
Moving towards 0 (position 810 '), post 825 will be in material 830
Are kept in contact with the mask material. By this method, protruding features can be applied to the mask material in a wide variety of shapes.

Other Modifications By taking the above teachings in combination, a person skilled in the art can use various developments of the teachings of the present invention. For example electroformed trace 250 using stencil 240
It is possible to define and produce traces using appropriate materials and laser reduction techniques, rather than defining.

Co-pending US patent application Ser. No. 08 / 819,4 filed March 6, 1997 by Eldridge et al. And owned by the applicant
No. 64 (currently pending) and its corresponding PCT patent application No. US97 / 08606 filed on May 15, 1997 (currently 1997 1
Published as WO97 / 43653 on Jan. 20), a contact tip structure is manufactured on a sacrificial substrate, and the prefabricated contact tip structure is mounted on the end of the elastic contact structure to remove the sacrificial substrate. A technique for removing is disclosed. Such techniques can be employed, for example, with respect to the contact structure 360 described so far, to impart a topology to the tip 362 of the contact structure.

The resulting contact structure is co-pending US patent application Ser. No. 08/9 filed Sep. 17, 1997 and owned by the present application.
As disclosed in No. 31,923 (currently pending), it can be heat treated to finely adjust its mechanical properties.

The nickel contact structure can be subjected to a "gold immersion" process known in the art to replace the outer (exposed) portion of the nickel contact structure with gold. This modifies the final contact properties of the contact structure and / or changes the metallurgical properties of the outer part of the nickel contact structure and also protects the contact structure in the subsequent selective etching process. Can play a role.

Conclusion Above is described a technique for manufacturing microelectronic contact structures on electronic components, where the contact structures are bonded (and electrically connected) to contact pads of the electronic component. A number of variants have been described, which include protruding features (eg 230,430) to change the topology of the tip of the contact structure, and contact structures (eg 460).
With or without the manufacture of the dies away from their corresponding contact pads, and controlling the geometry of the tip (eg 614) to facilitate robust fillet formation during soldering, etc. Is. The various techniques and structures disclosed herein can be "mixed and matched" with each other to create the variations described above, and various embodiments of contact structures may be used in any given application. It can also be placed on electronic components.

While the invention has been illustrated and described in detail in the drawings and foregoing description, it is to be considered that these are illustrative and not restrictive in character. It should be understood that only the preferred embodiment has been shown and described, and all changes and modifications that come within the spirit of the invention are desired to be protected. No doubt many other variations of the subject matter described above will occur to those of ordinary skill in the art to which the present invention best fits, and such variations may be found here. It is intended to be within the scope of the invention disclosed in.

─────────────────────────────────────────────────── --Continued from the front page (31) Priority claim number 09 / 032,473 (32) Priority date February 26, 1998 (February 26, 1998) (33) Country of priority claim United States (US) Previous Screening (56) Reference JP-A-8-276597 (JP, A) JP-A-7-333232 (JP, A) JP-A-9-27521 (JP, A) JP-A-9-512139 (JP, A) ) Table 9-505439 (JP, A) US Patent 5354712 (US, A) International Publication 96/15459 (WO, A1) International Publication 95/14314 (WO, A1) (58) Fields investigated (Int.Cl . ⁷ , DB name) H01L 23/12 H01L 21/60 311

Claims (65)

(57) [Claims] 1. A method of making a contact structure, comprising preparing an electronic component having a surface and a terminal adjacent to the surface, and depositing a mask layer having an opening adjacent to the surface on the electronic component. And depositing a seed layer of conductive material to form a proximal region of the seed layer above at least a portion of the terminal and a main body of the seed layer above at least a portion of the mask layer. A part region is formed, and the base end region and the main body part region are connected, and the length of the main body part region is between the base end part region and the tip part of the main body part region. A method that is curved to be longer than a linear distance and that comprises depositing a mass layer of conductive material on the seed layer to form a contact structure electrically connected to the terminal. 2. An initial conductive layer of conductive material is deposited over at least a portion of the electronic component and over at least a portion of the terminal prior to depositing the mask layer, and the initial conductive layer is then deposited. The method of claim 1, further comprising depositing the mask layer on at least a portion of the upper side. 3. The method of claim 1, further comprising removing the mask layer to release the resulting contact structure. 4. The method of claim 1, further comprising patterning the seed layer to define an elastic member profile. 5. Placing protruding elements on the mask layer and then depositing the seed layer to at least partially cover the protruding elements, thereby depositing the bulk layer of conductive material on the seed layer. A portion of the bulk layer is deposited on the seed layer on the protruding element, resulting in a conductive region that is further away from the electronic component than other portions of the bulk layer. the method of. 6. The method of claim 1, wherein the main body region of the seed layer is substantially parallel to the electronic component and is displaced from the surface thereof. 7. The method of claim 6, wherein the main body portion region is displaced from the surface of the electronic component by a distance of between about 125 μm and 5 mm. 8. The main body portion region is displaced from the surface of the electronic component by a distance of between about 50 μm and 200 μm.
The method of claim 6. 9. The method further comprising patterning the seed layer by depositing the seed layer through a shadow mask with one or more openings that define a desired seed layer shape. Method 1. 10. The method of claim 1, further comprising fabricating the opening in the mask layer to include a sloped region between a surface of the electronic component and a surface of the mask layer remote from the electronic component. the method of. 11. The method of claim 10, further comprising a connection region of the seed layer that includes at least a portion of the sloped region and that connects the main body region and the proximal region. 12. The method of claim 1, wherein the mask material has a thickness of between about 50 μm and 200 μm. 13. The opening in the mask layer includes a region on the surface of the electronic component, which includes some or all of the terminals and has an area of about 10,000 to about 42,000 μm ^2. Method 1. 14. The opening in the mask layer includes an area on the surface of the electronic component, which includes some or all of the terminals, and is sufficient to secure the final contact structure. Item 1 method. 15. The method of claim 10, wherein the sloped region has an average angle of between about 60 and about 75 degrees. 16. The method of claim 5, wherein the protruding elements protrude from the mask layer by about 50 to 175 μm. 17. The method of claim 5, wherein the protruding elements have a base dimension of between about 125 and about 375 μm. 18. The method of claim 1, wherein the seed layer has a thickness of between about 100 and 420 nm. 19. The method of claim 1, wherein the seed layer comprises gold with a thickness of about 250 to 420 nm. 20. The method of claim 1, wherein the seed layer comprises copper having a thickness of about 100 to 300 nm. 21. The method of claim 2, wherein the initial conductive layer has a thickness of between about 300 and about 600 nm. 22. The method of claim 2, wherein the initial conductive layer comprises an alloy of titanium and tungsten. 23. The method of claim 2, further comprising depositing a second conductive layer on the initial conductive layer. 24. The method of claim 23, wherein the second conductive layer is gold and has a thickness of between about 250 and about 450 nm. 25. The method of claim 1, wherein the mask material comprises a material selected from the group consisting of polyimide, novolac resin, and photoresist. 26. The method of claim 1, wherein the opening has sidewalls and the seed layer substantially covers the sidewalls. 27. The method of claim 1, wherein the opening has sidewalls and the seed layer only partially covers the sidewalls. 28. The method of claim 1, wherein the seed layer is deposited by a process selected from the group consisting of sputtering, chemical vapor deposition, physical vapor deposition, and electron beam deposition. 29. The method of claim 1, wherein the bulk layer of conductive material is deposited by electrolytic plating. 30. The bulk layer of conductive material is electrolytically plated,
Deposited by a process selected from the group consisting of electroless plating, chemical vapor deposition, physical vapor deposition, processes involving the deposition of materials from aqueous solutions, processes that result in the deposition of materials through the induced disintegration of liquid or solid precursors, The method of claim 1. 31. The method of claim 1, wherein the bulk layer of conductive material comprises nickel. 32. The bulk layer of conductive material is nickel,
A material selected from the group consisting of copper, cobalt, iron, gold, silver, platinum group elements, noble metals, semi-precious metals, palladium group elements, tungsten, and molybdenum.
the method of. 33. A conductive component is formed between the terminal of the electronic component and a remote terminal located on the surface of the electronic component and spaced apart from the terminal, and then the mask layer is formed with the opening in the terminal. And instead of depositing the seed layer and the agglomerate layer to contact the remote terminal according to the opening in the mask layer. Method. 34. The method of claim 1, further comprising manufacturing a separate tip structure and permanently bonding it to the contact structure to create a second modified contact structure. 35. Further comprising manufacturing a post structure connected to the separate tip structure and bonding the post structure to the contact structure to create a third modified contact structure. 35. The method of claim 34. 36. The electronic component is a semiconductor device.
The method of claim 1. 37. The method of claim 1, wherein the electronic component is a semiconductor device that is not individually cut from a wafer. 38. The electronic component is selected from the group consisting of a semiconductor device, a memory device, a portion of a semiconductor wafer, an entire semiconductor wafer, a space deformer, a ceramic device, a probe card, a chip carrier, and a socket. Method 1. 39. The method of claim 1, wherein the proximal region of the seed layer is in physical contact with the terminal. 40. The method of claim 1, wherein the proximal region of the seed layer is displaced from the terminal but in electrical contact with the terminal. 41. A method of manufacturing a contact structure having an inclined region, comprising: preparing an electronic component having a surface and a terminal adjacent to the surface, wherein the electronic component is provided with an opening adjacent to the terminal. Applying a mask layer on the component, the opening including a sloped region between the surface of the electronic component and the surface of the mask layer remote from the electronic component, and applying a bulk layer of elastic material, Connecting to at least a part of the terminal to form a proximal end region of the lump layer, covering at least a part of the mask layer to form a main body region of the lump layer, and forming at least one of the sloping regions. A contact structure electrically connected to the terminals and mechanically connected to the substrate in a fixed relationship such that the proximal region and the main body region are connected along a section. A method consisting of things. 42. The method of claim 41, further comprising removing the mask layer to release the resulting contact structure. 43. further comprising depositing a seed layer prior to applying the bulk layer, the seed layer connecting to at least a portion of the terminal to form a proximal region of the seed layer;
41. A main body portion region of the seed layer is formed to cover at least a part of the mask layer, and the base end region and the main body portion region are connected along at least a part of the inclined region. the method of. 44. The method of claim 41, further comprising patterning the seed layer to define an elastic member profile. 45. Patterning the seed layer by depositing the seed layer through a shadow mask with one or more openings defining a desired seed layer shape. 41 ways. 46. Patterning a main body region of the seed layer to include a generally annular region having a generally circular inner curve with an inner radius and a generally circular outer curve with an outer radius, 42. The method of claim 41, wherein the outer radius is greater than the inner radius, the center point of the inner radius is appropriately offset from the center point of the outer radius, and the substantially annular region outlines an elastic member. 47. Placing a protruding element on the mask layer and then depositing the lump layer to at least partially cover the protruding element and further away from the electronic component than other portions of the lump layer. 42. The method of claim 41, wherein a conductive region is provided. 48. The method of claim 41, wherein a main body region of the bulk layer is substantially parallel to the electronic component and is displaced from a surface thereof. 49. The method of claim 48, wherein the main body region is displaced from the surface of the electronic component by a distance of between about 50 μm and 200 μm. 50. The method of claim 41, wherein the sloped region has an average angle of between about 60 and about 75 degrees. 51. The method of claim 47, wherein the protruding elements protrude from the mask layer by about 50 to 175 μm. 52. The method of claim 43, wherein the seed layer comprises gold with a thickness of about 250 to 420 nm. 53. The method of claim 43, wherein the seed layer comprises copper having a thickness of about 100 to 300 nm. 54. The method of claim 41, wherein the bulk layer of conductive material is deposited by electrolytic plating. 55. The bulk layer of conductive material is electroplated,
Deposited by a process selected from the group consisting of electroless plating, chemical vapor deposition, physical vapor deposition, processes involving the deposition of materials from aqueous solutions, processes that result in the deposition of materials through the induced disintegration of liquid or solid precursors, 42. The method of claim 41. 56. The bulk layer of conductive material is nickel,
41. A material selected from the group consisting of copper, cobalt, iron, gold, silver, platinum group elements, noble metals, semi-precious metals, palladium group elements, tungsten, and molybdenum.
the method of. 57. Forming a conductive component between the terminal of the electronic component and a remote terminal located on the surface of the electronic component and spaced from the terminal, and then forming the mask layer with the opening in the terminal. 42. and further comprising: depositing over the remote terminal rather than, and further depositing the seed layer and the bulk layer to contact the remote terminal according to the opening in the mask layer. Method. 58. The electronic component is a semiconductor device.
42. The method of claim 41. 59. The electronic component is selected from the group consisting of a semiconductor device, a memory device, a portion of a semiconductor wafer, an entire semiconductor wafer, a space deformer, a ceramic device, a probe card, a chip carrier, and a socket. 41 ways. 60. The application of the mask layer further forms an opening in the mask material, the opening having a sidewall, wherein the sidewall of the opening becomes more sloping.
42. The method of claim 41, comprising reflowing the mask material in the area of the openings. 61. The application of the mask layer further exposes the mask layer to different degrees such that the deepest exposure of the mask material is parallel to the surface of the substrate and at the shallowest exposure of the mask material. Comprising a dimension smaller than the dimension and removing the exposed mask material to form an opening that generally narrows toward the surface of the substrate.
42. The method of claim 41. 62. The method of claim 61, further comprising varying exposure intensity for different depths of the mask material. 63. The method of claim 61, further comprising differentiating the pattern exposing the mask material such that a narrow pattern is used for deep exposures and a wide pattern is used for shallow exposures. 64. The opening wherein a molding member is formed within the opening, a first portion of the molding member is attached to the surface of the substrate, and a second portion of the molding member is in the mask material. 62. The method of claim 61, further comprising substantially conforming to the shape of. 65. The method of claim 64, further comprising removing the mask material to leave the molding adhered to the surface of the substrate.