JP3333403B2 - Probe device and inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an integrated circuit (IC).
The present invention relates to an apparatus for probe inspection, which is one of the performance inspections, and an inspection method using the same, and particularly to a structure of a probe apparatus suitable for simultaneously inspecting a large area and an inspection method using the same.

[0002]

2. Description of the Related Art Examples of known techniques related to this type of conventional probe apparatus include the following. Japanese Patent Application Laid-Open No. 7-283280 discloses a known technique in which a wafer on which a plurality of LSI elements each having an electrode pad for electrical connection to the outside is formed is mounted on a sample table, and these wafers are mounted on a sample support system. It is connected. On the other hand, a probe system including a probe, a connection device, a lead-out wiring, a buffer layer, and a wiring board is configured to be attached to the housing.

[0003] Japanese Patent Application Laid-Open No. Hei 5-243344 discloses a known technique including a buffer layer which is disposed between an operation board and a probe and comprises an elastomer layer and a flexible protective layer. The contact layer is relaxed, and a flexible protective layer protects the elastomer layer.

[0004] HOYA probe technology "membrane probe card" This known technique uses a pivot for supporting the membrane so that when the surfaces of the wafer and the bumps are not parallel when they come into contact with each other, they are slightly reduced. It can be modified in parallel. Note that, in any of the above-mentioned known techniques, basically, the sample support system is moved by driving the lifting / lowering drive unit provided below the sample support system, and the probe and the electrode pad are brought into contact with each other. It has a configuration. The probe is formed by bending a plurality of w-shaped needles or an aggregate of metal cores (bumps) formed on a thin film of polyimide resin or the like. Each probe has a size of about 5 to 20 gf. It is pressed against the electrode pad by the pressing load.

[0005]

In general, in order to improve the performance of a probe device, it is important to reduce the amount of pressure (= variation in load at the time of pressing) on the electrode pad for each probe. This will be described with reference to FIG.

FIG. 6 is a longitudinal sectional view showing the structure of a conventional general probe device. As shown in FIG. 6, usually, at the stage of constructing the entire probe device, manufacturing and mounting errors of the respective structures are made. , The probe surface (the surface formed by the probe tip) 11 has an unavoidable inclination dθ relative to the wafer 20 (or the wafer stage 21). Due to this inclination, a difference in apparent height, that is, a variation occurs between the probes 101a and 101z at both ends of the probe surface 11, so that a difference occurs in the amount of pressing against each electrode pad in the wafer 20.

In recent years, in order to improve the productivity of LSI, the size of a wafer to be inspected has been increased and a larger number of semiconductor elements have been formed. As a result, a larger number of element groups have been formed in the wafer. Plans are being made to perform a simultaneous inspection of all devices (and all devices). The difference in the amount of pressing described above is inevitably larger as the inspection area (wafer diameter in the case of simultaneous inspection of the wafers 20) becomes larger. The difference in height usually amounts to tens of μm. Therefore, in future probe devices, it is required to sufficiently reduce the variation in the pressing load of each probe scattered in a larger area.

[0008] In view of the above-mentioned known technique from the viewpoint of preventing the variation in the pressing amount as described above, the following problems exist. That is, in the known technology and the buffer layer provided in the known technology, the variation in the pressing force can be reduced to some extent. However, it is difficult to select a physical property value (elastic modulus) of the buffer layer. If the buffer layer is too small, it shrinks to the limit. And even if you choose the right value,
Since the variation still remains in proportion to the initial value, it is difficult to sufficiently reduce the variation in the pressing amount.
In addition, the pivot mechanism provided in the known technique exerts a parallel adjustment operation between the probe surface and the wafer surface immediately after the first contact between any probe and the electrode pad, and can reduce the variation in the pressing force to some extent. However, due to the total pressing load (= 5 to 20 gf × the number of probes) of the device that increases with the number of probes, the sliding frictional force at the tip of the pivot increases, and the parallel adjustment function may not work. It is difficult to sufficiently reduce the variation.

If the variation in the pressing amount is not sufficiently reduced, there are the following problems. This will be described with reference to FIGS. That is, in a pad with an excessively small pressing amount, for example, as shown in FIG.
7 is inhibited, while the probe 101 is connected to the electrode 202 as shown in FIG.
To the Si substrate 203 which is a brittle material, and may damage the Si substrate 203. Therefore,
Usually, in a general LSI, the thickness of the electrode is manufactured between 0.6 and 1.0 μm, so that the variation of the pressing amount needs to be within the range. But,
Even if the variation is controlled within the range, the difference in the pressing amount causes a difference in the plastic deformation (inspection mark) generated on the surface of the electrode pad. This will be described with reference to FIG. FIG. 8 is a conceptual explanatory diagram illustrating a cross section of the inspection mark generated on the electrode pad. In FIG. 8, the probe surface 11
Is tilted dθ, the probe 1
Is generated, a burr 1t and a pad fragment 1u are generated in the sliding direction. Among these phenomena, burr 1
The "t" may be an obstacle in performing wire bonding to this portion later, and the fragment "1u" may lead to contamination of the wafer, the probe 101, or the production environment. These phenomena become more remarkable as the pressing amount increases.

[0010] Further, the difference in the amount of pressing affects the life of the probe tip. A probe having a large pressing amount has a large amount of tip wear and a large amount of attached pad pieces, which shortens the life of the probe. Inevitably, the lifetime of the entire probe system is determined by the shortest-lived probe. This inconvenience occurs for the probe with the largest pressing amount in order to make good contact with the probe with the smallest pressing amount.

Here, in order to solve the above inconveniences, the following known techniques have been proposed. In this known technique, the arm fixed to the lower part of the sample stage is driven up and down by a motor or the like, and the sample stage is tilted in accordance with the inclination of the probe surface, thereby reducing the variation in the pressing amount. It is intended.

In this known technique, the bottom of the sample stage is formed in a hemispherical shape, the length of a support arm for supporting the sample stage is variable, and the length of the sample stage is adjusted according to the inclination of the probe surface. This controls the inclination.

[0013] Japanese Patent Application Laid-Open No. H7-94561 discloses a conventional technique in which a fluid chamber is provided on the back surface of a flexible probe card so that even if there are some irregularities in the contact pad of the wafer, the contact pad and the probe can be connected. This ensures reliable contact.

However, these known techniques have the following problems. That is, in the known technology, the probe surface and the sample stage are finally pressed in parallel, but the parallel adjustment is performed before the contact,
It is not clear whether parallel adjustment is performed after contact. After the contact, similar to the above-described known technique, the parallel adjustment function may not work due to an increase in the total pressing load of the device, and it is difficult to sufficiently reduce the variation in the pressing amount. Even in the case of performing parallel adjustment before contact, when the probe surface is tilted, the sample stage is tilted from the z direction in accordance with the tilt, and the sample stage is moved in the z direction while keeping the tilted state. That is, since the moving direction of the sample table and the direction of the wafer surface do not match, the probe may scratch the wafer surface during contact and the length of the wafer may be increased, which may increase the damage to the wafer. Further, in the known technique, as described above, there is a problem of wafer damage due to the fact that the direction of movement of the sample table and the direction of the surface of the sample table do not match. And the structure becomes complicated. Further, the temperature of the sample stage is set to a high temperature during the test. However, since the detection accuracy of the sensor is reduced by this, there is a problem that it is difficult to obtain high accuracy. Further, in the known technology, since the probe is configured to perform parallel adjustment after contacting the wafer, the parallel adjustment function may not work due to an increase in the total pressing load of the device, as described in the known technology above, and the pressing may be performed. It is difficult to sufficiently reduce the variation in the amount. In addition, a mechanism for taking a fluid in and out of the fluid chamber is required, and the structure becomes complicated. Further, when the wafer area is large, there is also a problem that it is difficult to press with high precision at the end of the fluid chamber.

The present invention has been proposed to solve the above-mentioned disadvantages, and has as its object a simple structure which prevents damage to the wafer while preventing the probe surface from being moved between the probe surface and the wafer (or wafer stage). An object of the present invention is to provide a probe device capable of sufficiently reducing a relative tilt and an inspection method using the same.

[0016]

According to the present invention, there is provided a wafer stage on which a wafer to be inspected is mounted, a plurality of probes for contacting electrode pads of the wafer, and A pressing body for pressing the probe downward, a card connected to an upper portion of the pressing body, and wiring means for electrically connecting the multi-layer wiring of the card to the plurality of probes; And a probe device for relatively moving the wafer stage and the plurality of probes and testing the electrical characteristics by contacting the plurality of probes with the electrode pads of the wafer, wherein the wafer and the wafer The frame further includes a frame that can be in contact with any one of the stages, and an elastic body provided between the frame and the pressing body, and the frame has a lower surface that is forward. The plurality of probes are connected to the pressing body so as to be parallel to the plane formed by the lower surfaces, and the lower end position is located below the lower surfaces of the plurality of probes, and the pressing body has at least one of the upper ends. The part has a pivot having a curved shape at the upper part, the card has a hollow convex part, at least a part of the inside of the hollow convex part,
A probe device is provided which has a curved shape that engages with the curved shape of the pivot. That is, when the wafer stage and the probe are relatively moved and approached to perform an inspection, first, the lower surface of the frame whose lower end position is below the probe comes into contact with the wafer or the wafer stage, and almost no space exists. Under load, the lower surface of the frame and the wafer are adjusted in parallel. As a result, the probe below the pressing body connected to the frame is in a parallel position with the wafer. Thereafter, when the wafer stage and the probe are further brought closer to each other, the curved surface of the pivot provided on the card and the curved surface of the pressing body hollow convex portion that engages with the contact come into contact, and the pressing body moves downward through this. Is pressed. At this time, even if the card is inclined with respect to the wafer surface, the curved surface shape of the pivot and the curved surface shape of the hollow convex portion contact each other at positions deviated from the center, so that the card is always in the vertical direction with respect to the wafer surface. Is pressed. Therefore, unlike the conventional structure, there is no occurrence of wafer damage due to the inconsistency between the moving direction of the wafer stage and the direction of the wafer surface. When the wafer stage and the probe are further brought closer to each other, the elastic body between the frame and the pressing body shrinks and the distance between the probe and the wafer on the lower surface of the pressing body is reduced in such a vertically pressed state. And the probe can eventually come into contact with the electrode pads in the wafer. This makes it possible to sufficiently reduce the relative inclination between the probe surface formed by the lower surfaces of the plurality of probes and the wafer with a simple structure.

Preferably, in the probe device,
A probe device is provided, wherein the shape of the pivot upper end and the shape of the inside of the hollow convex portion are substantially hemispherical.

Preferably, in the probe device, a substantially convex shape is formed on a lower end surface of the frame.
A probe device is provided, wherein a substantially concave shape is formed on the upper surface of the wafer stage so as to engage with the substantially convex shape of the frame. Thus, when the lower surface of the frame comes into contact with the wafer or the wafer stage and the parallel adjustment of the lower surface of the frame and the wafer is performed, the relative positional relationship between the two in the plane direction can be fixed. Therefore, a more stable and reliable operation can be performed.

Preferably, in the probe device, a linear drive bearing acting in a pressing direction of the pressing body is provided on an outer peripheral portion of the pressing body, and the pressing body is provided with:
A probe device is provided, which is slidably inserted into the inner periphery of the frame via the linear drive type bearing. Thus, the relative positional relationship between the pressing body and the frame body in a direction other than the driving direction of the linear drive type bearing can be fixed, so that a more stable and reliable operation can be performed.

Preferably, in the inspection method for inspecting electrical characteristics of a semiconductor element provided in the wafer using the probe device, any one of the wafer and the wafer stage, the lower surface of the frame, Then, the curved surface shape of the pivot of the pressing body and the curved surface shape of the hollow convex portion of the card,
Thereafter, an inspection method is provided wherein the plurality of probes are brought into contact with the electrode pads of the wafer.

[0021]

An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are side sectional views showing the structure of the probe device according to the present embodiment and the inspection method using the same. In addition, the same code | symbol is attached | subjected to the member equivalent to FIGS. 6-8 of a conventional structure. 1 to 3, the probe device of the present embodiment includes a wafer stage 21 on which a wafer 20 to be inspected is placed, and a probe system 10.

The probe system 10 generally includes a thin film 102 having a plurality of probes 101 that are in contact with an electrode pad (not shown) of the wafer 20, and the thin film 102 is formed on the lower surface and presses the probe 101. Pressing body 104
And a card 107 having a multilayer wiring 106 and connected to the upper part of the pressing body 104, and a multilayer wiring 10 of the card 107.
FPC 109 and bump 110 constituting wiring means for electrically connecting probe 6 and probe 101, frame 112 that can be brought into contact with wafer stage 21 (described later), frame 11
2 and an elastic body 111 provided between the pressing body 104, the wafer stage 21 is relatively moved with respect to the probe 101, and the probe 101 is
And inspect the electrical characteristics by contacting the electrode pads.

The thin film 102 is made of a polyimide film or the like, and the probe 101 is formed by a known method (for example, etching). Further, the thin film 102 is joined to the lower surface of the pressing body 104 via a rubber elastic body 103 for buffering a variation in the height of each probe 101. Further, the thin film 102 is provided with wiring (not shown) for transmitting an electric signal,
Are joined by a bump 110 via an FPC 109.

A pivot 105 having a substantially hemispherical upper end is provided on the upper part of the pressing body 104.
It is dressed hanging by the pivot 105.

At the top of the card 107, there is provided a hollow 108, which is a hollow convex part. The inside of the hollow 108 has a substantially hemispherical shape that engages with and contacts the substantially hemispherical shape of the pivot 105. It has.

The frame 112 is joined to the pressing body 104 via the elastic body 111. At this time, the lower surface of the frame 112 is parallel to the surface (probe surface) formed by the lower surfaces of the plurality of probes 101 and The lower end position of the frame 112 is configured to be located below each probe 101.
At this time, the frame 112 may be formed in a ring shape so as to surround the periphery of the wafer 20, or may be partially arranged around the wafer 20.

An inspection procedure by the inspection apparatus having the above configuration will be described below with reference to FIGS. First, as described in the section of the problem to be solved by the invention, the probe system 10
The inclination is unavoidable due to the configuration with respect to the surface of the wafer 20 or the surface of the wafer stage 21. FIG. 1 shows this state. In this state, the wafer stage 21 is moved in the vertical direction (the direction of the arrow y1) in order to make contact between the probe 101 and the electrode pad of the wafer 20. As a result, first, the frame 11 of the probe system 10
2 is in contact with the wafer stage 21 and still has y1
By continuing the movement in the direction, the probe surface and the wafer 20 surface are adjusted in parallel with no load. As a result, the probe surface below the pressing body 104 connected to the frame 112 and the wafer 20 are in a parallel position. The frame 112 contacts the wafer stage 21 and the wafer 20 at the same time. This state is shown in FIG.

Thereafter, when the movement in the y1 direction is further continued, the substantially semi-curved surface of the pivot 105 provided on the card 107 and the depression 108 of the pressing body 104 engaged therewith
And the pressing body 104 is pressed downward through this. At this time, the substantially spherical shape of the pivot 105 and the curved surface shape of the recess 108 are in point contact with each other at positions deviated from the center, so that the wafer 20 is always pressed from the vertical direction. Therefore, unlike the conventional structure, damage to the wafer 20 due to the inconsistency between the moving direction of the wafer stage 21 and the direction of the surface of the wafer 20 does not occur.

When the movement in the y1 direction is further continued, the elastic body 111 between the frame body 112 and the pressing body 104 is contracted in the above-mentioned vertical pressing state, and the probe below the pressing body 104 is contracted. The distance between 101 and wafer 20 is reduced, and probe 101 and the electrode pad in wafer 20 can be finally brought into contact.

According to the above inspection performed using the probe device of the present embodiment, the relative inclination between the probe surface and the wafer 20 can be sufficiently reduced with a simple structure. Therefore, even when a large area simultaneous inspection of many element groups formed in the wafer 20 is performed, the probe 1
01 can be sufficiently reduced.
It is possible to reduce the possibility that inconveniences such as damage to the wafer Si substrate, contamination of the production environment, and shortening of the life of the probe as in the conventional structure occur.

In the above embodiment, the frame 11
Although 2 was in contact with both the wafer stage 21 and the wafer 20, it is not always necessary, and it is sufficient that it is in contact with either the wafer stage 21 or the wafer 20. In this case, a similar effect is obtained. In the above embodiment, the FPC 109 is interposed for electrical connection between the wiring on the thin film 102 and the multilayer wiring 106. However, the wiring on the thin film 102 can be electrically connected to the multilayer wiring 106 by itself. In this case, there is no need to use the FPC 109 between the two. In this case, a similar effect is obtained. Further, in the above-described embodiment, the shape inside the pivot 105 and the recess 108 is a substantially hemispherical shape, but is not limited thereto. In other words, it suffices that these have at least a part in a curved shape and can be engaged with each other via the curved surface. In the above embodiment, the probe 101 is a so-called thin-film probe formed in the thin film 102. However, the present invention is not limited to this. For a so-called contact-needle probe in which the probe is formed by bending a metal rod. Can also be applied, and in this case, a similar effect is obtained.

The present embodiment can be modified in addition to the above without departing from the spirit thereof. This will be described below.

(1) Modifications Regarding Shapes of Frame and Wafer Stage That is, as shown in FIG. 4, a substantially convex shape 112A is formed on the lower end surface of the frame 112, and the frame is formed on the upper surface of the wafer stage 21. The V-groove 211 is formed as a substantially concave shape that engages with the substantially convex shape 112A of the 112.
Other configurations and inspection procedures are almost the same as those in FIGS. Thereby, when the lower surface of the frame 112 comes into contact with the wafer stage 21 and the parallel adjustment of the lower surface of the frame 112 and the wafer 20 is performed, the relative positional relationship between the two in the plane direction can be fixed, so that more stable. A reliable and reliable operation can be performed. In particular, card 1 as shown
In the case where a hole larger than the diameter of the shaft 1041 of the pressing body 104 is provided in 07, the displacement can be effectively prevented, and good contact can be achieved.

The V-groove 211 and the substantially convex shape 112A
The shape is not limited to the shape shown in FIG. 4, and the shapes may be in contact with each other including, for example, a plurality of flat surfaces and curved surfaces. Although the frame 112A is in contact only with the wafer stage 21 in the drawing, a configuration in which both the wafer stage 21 and the wafer 20 are in contact as shown in FIGS. In these cases, a similar effect is obtained.

(2) Modification of Connection Between Pressing Body and Frame via Elastic Body That is, as shown in FIG. 5, a linear drive type bearing 1111 acting in the pressing direction of the pressing body 104 is connected to the pressing body 10.
4, and the pressing body 104 is slidably inserted into the inner periphery of the frame 112 via a linear drive type bearing 111. FIG. 5 shows the probe 101, the thin film 102, and the rubber elastic body 10 in order to avoid complication of the drawing.
Although illustrations of the 3. FPC 109, the bump 110, and the like are omitted, their configuration is almost the same as in FIGS.

With the above configuration, the linear drive type bearing 1
Pressing body 104 and frame 11 in directions other than driving direction of 111
2 can be fixed, so that a more stable and reliable operation can be performed. In particular, even if the characteristics (spring constant) of the elastic body 111 are deviated depending on the location, it is possible to always press the wafer 20 in the vertical direction.

[0037]

According to the present invention, the relative inclination between the probe surface and the wafer can be sufficiently reduced with a simple structure. Therefore, even when performing a large-area simultaneous inspection of a large number of elements formed in the wafer at the same time, the variation in the pressing load of the probe can be sufficiently reduced. It is possible to reduce the possibility that inconveniences such as contamination and shortened probe life will occur.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a structure of a probe device according to an embodiment of the present invention and an inspection method using the same.

FIG. 2 is a side sectional view showing a structure of a probe device according to an embodiment of the present invention and an inspection method using the same.

FIG. 3 is a side sectional view showing a structure of a probe device according to an embodiment of the present invention and an inspection method using the same.

FIG. 4 is a side sectional view illustrating a modification example regarding the shapes of a frame and a wafer stage.

FIG. 5 is a side sectional view showing a modification example of connection between the pressing body and the frame via an elastic body.

FIG. 6 is a longitudinal sectional view illustrating a configuration of a conventional general probe device.

FIG. 7 is an explanatory diagram showing the inconvenience due to damage to an oxide film and a Si substrate in a conventional general probe device.

FIG. 8 is an explanatory view showing inconvenience due to a difference in the pressing amount in a conventional general probe device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Probe system 20 Wafer 21 Wafer stage 101 Probe 102 Thin film 104 Pressing body 105 Pivot 106 Multilayer wiring 107 Card 108 Recess 109 FPC (Wiring means) 110 Bump (Wiring means) 111 Elastic body 112 Frame 112A Substantially convex shape 211 V groove ( (Substantially concave shape) 1111 linear drive type bearing

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Kitano 502 Kandachi-cho, Tsuchiura-city, Ibaraki Pref. Examiner, Machinery Research Laboratory, Hitachi, Ltd. Yoshinari Tashiro (56) Reference JP-A 9-21828 (JP, A) JP-A-8-83824 (JP, A) JP-A-9-36188 (JP, A) JP-A-9-43276 (JP, A) JP-A-10-26636 (JP, A) (58) Int.Cl. ⁷ , DB name) H01L 21/66 G01R 31/26

Claims (5)

(57) [Claims] 1. A wafer stage on which a wafer to be inspected is placed, a plurality of probes in contact with electrode pads of the wafer, a pressing body for pressing these probes downward, and multilayer wiring. A card connected to the upper part of the pressing body; and wiring means for electrically connecting the multilayer wiring of the card and the plurality of probes. In the probe device to inspect the electrical characteristics by contacting the plurality of probes to the electrode pads of the wafer, a frame body that can contact any one of the wafer and the wafer stage, And an elastic body provided between the pressing body and the frame so that a lower surface thereof is parallel to a surface formed by lower surfaces of the plurality of probes. A lower end positioned below the lower surfaces of the plurality of probes, the lower end being located below the lower surfaces of the plurality of probes, the upper end being provided with a pivot having at least a part of an upper end curved; Has a hollow convex portion, and at least a part of the inside of the hollow convex portion has a curved surface shape that engages with the curved surface shape of the pivot. 2. The probe device according to claim 1, wherein the shape of the upper end of the pivot and the shape of the inside of the hollow convex portion are:
A probe device having a substantially hemispherical surface. 3. The probe device according to claim 1, wherein a substantially convex shape is formed on a lower end surface of the frame, and a substantially concave shape which engages with the substantially convex shape of the frame is formed on an upper surface of the wafer stage. A probe device characterized by being formed. 4. The probe device according to claim 1, wherein a linear drive type bearing acting in a pressing direction of said pressing body is provided on an outer peripheral portion of said pressing body, and said pressing body is provided with said linear driving type bearing. A probe device, which is slidably inserted and disposed on the inner periphery of the frame body. 5. An inspection method for inspecting electrical characteristics of a semiconductor element provided in the wafer using the probe device according to claim 1, wherein one of the wafer and the wafer stage and the frame body are inspected. Contacting the lower surface with the curved shape of the pivot of the pressing body and the curved shape of the hollow convex portion of the card; and then bringing the plurality of probes into contact with the electrode pads of the wafer. An inspection method characterized by the following.