JP2689938B2 - Probe card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card used for measuring electrical characteristics of semiconductor elements, and more particularly to a membrane type probe card.

[0002]

2. Description of the Related Art A conventional membrane probe card will be described with reference to FIGS. FIG. 5 is a sectional view showing an example of a conventional membrane probe card, FIG. 6 (a),
FIG. 7B is a sectional view showing a main part of the conventional membrane probe card at the time of measurement, and FIG. 7 is a sectional view showing another example of the conventional membrane probe card.

In a manufacturing process of a semiconductor integrated circuit device (IC), a probe corresponding to an electrode pattern of a semiconductor element is used as an inspection apparatus (hereinafter referred to as a prober) for measuring electric characteristics of a semiconductor element formed on a wafer. Generally, a probe card in which is fixed to an insulating substrate is used. In particular, in order to cope with narrower pitch and higher speed of devices, a membrane type probe card by bump contact has also been used, and is disclosed in JP-A-1-269065, JP-A-2-126159, and JP-A-2-126160. , JP-A-2
-141681, JP-A-2-163664. As shown in FIG. 5, the membrane probe card includes a wafer 1c, a thin film 2c which is a contact portion, an insulating substrate 3c for fixing the thin film 2c, and a metal protrusion 4c of the thin film 2c.
Includes a component fixed so as to project from the lower surface of the insulating substrate 3c. Then, a conductor pattern having a contact piece at the tip is formed on the insulating substrate 3c.

The thin film 2c is made of a flexible film such as polyimide, and a metal projection 4c corresponding to the electrode pad 6c of the semiconductor element 5c on the wafer to be measured is formed on the lower surface of the film. Then, a conductor pattern 7c is formed on the upper surface of the film from the protrusion 4c through the through hole to the outer peripheral portion of the film, and a contact piece is provided at the tip of each pattern on the outer peripheral portion of the film. The pattern is connected between the insulating substrates 3c and the pattern provided in the periphery of the insulating substrate 3c through the contact piece provided at each tip. Further, the insulating substrate 3c and the translation table 8c are connected by a leaf spring 9c, and the thin film 2c is also connected to the translation table 8c. Further, on the back side of the central region of the thin film 2c, a disc-shaped pressing plate 1 with an elastic body 10c sandwiched therebetween.
1c is arranged and kept pressed against the membrane 2c by a shaft 13c extending from a shaft-fixing reference plate 12c in the central cavity of the translation table 8c. With the above structure, the thin film 2c is
The metal protrusion 4c of the thin film 2c is fixed so as to protrude from the lower surface of the insulating substrate 3c. The wafer 1c is mounted on a stage (not shown) of a prober, and the metal protrusion 4c of the probe card and the electrode pad 6c of the semiconductor element 5c on the wafer 1c come into contact with each other due to the rise of the stage, and the electrical characteristics are measured. A bearing is provided on the pressing plate 11c, and a mechanism for forcing the parallelism with the wafer 1c with the bearing as a fulcrum is provided. Further, the elastic body 10c plays a role of absorbing the height variation of the metal protrusion 4c. Further, a metal conductor layer 14c is provided on the back surface side of the conductor pattern 7c of the thin film 2c and is grounded (GND) to form a microstrip line structure, thereby achieving impedance matching and low inductance. In the conventional membrane probe card, the pressing plate made of glass or the like has a columnar shape that is considerably larger than the outer dimensions of the semiconductor element 5c. Therefore, when contacting the wafer, the adjacent semiconductor element on the wafer and the GND plane on the lower surface of the thin film are used. A certain metal conductor layer 14c contacts and V of each semiconductor element on the wafer
ID for products to which the _DD (power supply voltage) terminal is connected
D (power supply current) defects and leak defects frequently occurred, and pads and thin films were burned. In order to solve the above-mentioned problem, as shown in FIG. 7, the outer shape of the pressing plate 11d is improved to the same extent as the outer dimension of the semiconductor element 5d to prevent contact between the adjacent semiconductor element and the GND plane on the lower surface of the thin film during measurement. Was there.

[0005]

In the conventional membrane probe card, since the pressing plate made of glass or the like has a columnar shape which is considerably larger than the outer dimensions of the semiconductor element,
As shown in FIG. 5, in the case of a product in which the adjacent semiconductor element on the wafer and the GND plane on the lower surface of the thin film are in contact with each other at the time of contact with the wafer, and the V _DD terminal of each semiconductor element is connected on the wafer, IDD failure occurs. Many leaks and leaks occurred, and the pads were burned. Further, in the probe card in which the outer shape of the pressing plate is improved to the same extent as the semiconductor element outer dimension to solve the above problems, the pressing plate warps due to the load from the shaft portion and the tension of the thin film as shown in FIG. Therefore, there is a problem that contact failures frequently occur. Even if the pressing plate is cylindrical, the pressing plate warps, but since the tension due to the thin film is uniform, the influence of the floating of the metal protrusion due to the difference in the warp amount is small in the vicinity of the metal protrusion. However, when the pressing plate has a rectangular shape, the amount of warpage is different due to the imbalance of the tension on the short side and the long side, especially near the corners, and the metal projections in the vicinity contact less than others. Even if a contact is made, it does not penetrate through the non-conductive aluminum oxide on the electrode pad to reach the aluminum of the conductor to obtain a good connection.

For example, the external dimensions are 12.0 mm × 16.0
mm, the number of electrode pads is 500, the pitch of the metal projections is about 100 μm, and the height of the metal projections is about 30 μm, the difference in the warp amount of the pressing plate due to the tension of the thin film of the membrane probe card is Division (distance from center =
6.0 mm) and corner (distance from center = 10.0)
mm) can be about 10 μm. Then, at the time of contact with the wafer, a load of about 5 kg is applied to the central portion of the element, and the pressing plate is kept in a warped state. The height variation of the metal projection is absorbed by the elastic body at most about 6 μm, and the floating amount of the metal projection caused by the difference in the warp amount of the pressing plate cannot be completely absorbed, resulting in poor contact. Since the amount of warpage is proportional to the cube of the distance, this problem becomes more remarkable as the outer dimensions of the semiconductor element increase.

[0007]

A probe card according to the present invention has an opening inside and an insulating substrate having a plurality of contact pieces provided in a peripheral region of the opening, and an outer peripheral portion of the insulating substrate. A plurality of contact pieces corresponding to the contact pieces in the peripheral region, and a plurality of metal protrusions corresponding to the electrode pads arranged on the upper surface of the semiconductor device under test, which are fixed to And a thin film having a plurality of conductor patterns extending from the plurality of contact pieces to the metal projections, and a translation table connected to the insulating substrate via a leaf spring and provided in the central region of the opening. An upper side surface provided with a concave receiving portion for receiving a lower end portion of a shaft extending downward from the shaft fixing reference plate, and a pressing plate having a lower side surface contacting the upper surface of the thin film from above via an elastic body. The contact of the outer periphery of the thin film Are connected to contact pieces of an insulating substrate provided in the peripheral region of the opening, and the lower surface of the thin film having the metal protrusions projects downward from the lower surface of the insulating substrate. In the above, the pressing plate has a cylindrical side surface concentric with the shaft, and the lower side surface contacting the upper surface of the central portion of the thin film via an elastic body has the same dimension as the external dimensions of the semiconductor device under test. A slanting surface having a shape projecting downward is formed between the lower edge of the cylindrical side surface and the lower side surface, and the slanting surface is in contact with the upper surface of the thin film. Is characterized by.

Further, the thin film and the elastic body are characterized in that an inner portion surrounded by a plurality of metal projections is opened.

[0009]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a membrane probe card according to an embodiment of the present invention, and FIGS. 2A and 2B are cross-sectional views showing a main portion at the time of measurement according to the embodiment of the present invention. As shown in FIG. 1, the membrane probe card includes a thin film 2a which is a contact portion with the wafer 1a and a thin film 2a.
And an insulating substrate 3a for fixing the plurality of metal projections 4a.
The thin film 2 so that it projects downward from the lower surface of the insulating substrate 3a.
It is provided at the contact portion a. The thin film 2a is made of a flexible film such as polyimide, and a metal projection 4a corresponding to the electrode pad 6a of the semiconductor element 5a on the wafer 1a to be measured is formed on the lower surface of the film. Then, a conductor pattern 7a is formed on the film upper surface up to the film outer peripheral portion from the protrusion 4a through the through hole, and is provided around each conductor pattern 7a on the film outer peripheral portion and the opening of the insulating substrate 3a. The pattern and the pattern are connected to each other via a contact piece provided at the tip.

Further, the insulating substrate 3a and the translation table 8a are connected by a leaf spring 9a, and the thin film 2a is also connected to the translation table. Further, the elastic body 10 is provided inside the central region of the thin film 2a.
A disk-shaped pressing plate 11a sandwiching a is arranged, and this pressing plate is a shaft fixing reference plate 12a in the central cavity of the translation table 8a.
It is kept pressed against the thin film 2a by a shaft 13a extending from. With the above configuration, the membrane probe card is fixed such that the metal protrusion 4a of the thin film 2a projects downward from the lower surface of the insulating substrate 3a. A bearing for receiving the tip of the shaft 13a is provided at the center of the upper surface of the pressing plate 11a, and a mechanism for maintaining the parallelism between the pressing plate and the wafer with this bearing as a fulcrum is provided. Further, the elastic body 10a plays a role of absorbing the height variation of the metal protrusion 4a. Furthermore, by providing the metal conductor layer 14a on the back surface side of the conductor pattern of the thin film 2a, impedance matching and low inductance are achieved.

In the probe card of the present invention, the metal protrusion 4
The pressing plate 11a for contacting a with the semiconductor element 5a under test has an upper surface on which a bearing for receiving the shaft 13a is formed and a cylindrical side surface, and the lower contact surface that contacts the wafer is a semiconductor. The external dimensions of the element are the same as those of the element, and an inclined surface that projects downward is formed between the lower edge of the cylindrical side surface and the outer edge of the contact surface with the wafer. This inclined surface has a structure in which the thin film 2a is pushed downward from the inside. The wafer 1a to be measured is mounted on the stage of the prober, and after alignment, the stage moves up and, as shown in FIGS. 2A and 2B, the metal protrusions 4a of the probe card and the semiconductor on the wafer 1a. The electrode pad 6a of the element 5a contacts, and the electrical characteristics are measured.

At this time, the pressing plate of the membrane probe card is shaped like a cylinder on the upper surface side in contact with the shaft 13a, and on the other hand, the surface corresponding to the wafer is set to the outer dimension of the semiconductor element to be tested, so that the GND surface of the lower surface of the thin film is grounded. It is possible to completely prevent IDD defects, leak defects and burnout of pads and thin films caused by contact between the semiconductor element adjacent to the plane and the metal conductor layer 14a. Furthermore, the tension of the thin film is buffered by the structure in which the circumferential part, which is the lower inclined surface of the cylinder of the pressing plate, pushes out the thin film from the inside.
The tension can be reduced to less than half. That is, conventionally, since the thin film having tension was only in contact with the rectangular or square lower surface of the pressing plate, the tension was concentrated on the lower surface. Since the thin film having tension contacts the lower surface of the pressing plate and the conical side surface, the tension of the thin film is dispersed between the lower surface and the side surface, and the cylindrical portion has the conventional shape. Since it becomes thicker and stronger than the retaining plate, it has the effect of preventing the retaining plate from warping. For example, the external dimensions are 12.0 mm x 1
For a semiconductor device having a size of 6.0 mm, a number of electrode pads of 500, a pitch of metal projections of about 100 μm, and a height of metal projections of about 30 μm, the difference in the warp amount of the pressing plate due to the tension of the thin film of the membrane probe card is 5 μm or less. Can be As a result, the floating amount of the metal protrusions of the probe card can be absorbed by the elastic body when contacting the wafer, and uniform contact can be obtained for all electrode pads. Then, the unevenness of the needle traces is eliminated, the contact resistance between the metal protrusion and the semiconductor element pad is stabilized, and the occurrence of contact failure can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 (a) and 3 (b) are sectional views showing a main part at the time of measurement of the second embodiment of the present invention,
FIG. 4 is a plan view showing the metal protrusion side of the probe card of the second embodiment. In this embodiment, the central portion inside the thin film 2b and the metal protrusion 4b of the elastic body 10b is opened. The thin film 2b has a thickness of about 25 μm, the elastic body 10b has a thickness of about 150 μm, and the metal protrusion 4b has a height of 30 μm. In the conventional membrane probe card, when measuring the semiconductor element on the wafer, the gap between the surface of the active area of the semiconductor element to be measured and the thin film of the probe card is only the height of the metal protrusion (about 30 μm), and it is possible to remove aluminum scraps or the like. If dust adheres to the surface of the semiconductor element, the dust may be transferred to the probe card and the circuit on the element surface may be damaged by the dust during subsequent measurement of the semiconductor element, resulting in electrical failure. There was a nature. In this embodiment, the wafer 1b
At the time of measurement, the gap between the surface of the active region of the semiconductor element 5b to be measured and the central portion inside the metal protrusion 4b of the probe card is about 2 mm.
It becomes 00 μm. As a result, 100 μm on the device surface
Even if a large amount of dust is present, it is not transferred to the probe card, and the problem that dust and the like damages the element surface and frequently causes defects can be prevented.

[0014]

As described above, according to the present invention, the shape of the pressing plate of the membrane probe card is cylindrical on the upper surface side in contact with the shaft portion, and the surface corresponding to the wafer is the outer dimension of the semiconductor element to be tested. By forming an inclined surface projecting downward between the cylindrical portion and the surface corresponding to the wafer, IDD defects, leak defects, and pads caused by contact between an adjacent device and a thin film GND plane during wafer measurement. Can be completely prevented from burning.

Further, since the inclined peripheral portion of the lower side of the cylinder of the pressing plate is in contact with the thin film and the thin film is extruded from the inside, the lower peripheral portion of the cylinder of the pressing plate is formed of the thin film. Since the tension can be buffered and the tension of the thin film can be reduced to less than half, the floating amount of the metal protrusions of the probe card can be absorbed by the elastic body when contacting the wafer, and uniform contact can be obtained for all electrode pads. Further, the contact resistance between the metal protrusion and the semiconductor element pad is stable, and the occurrence of contact failure can be prevented.

Further, a portion of the thin film and the elastic body which is inside the metal protrusion is opened so that a gap between the surface of the active region of the semiconductor element to be measured and the inner side of the metal protrusion of the probe card (pressing plate) is about 200 μm during wafer measurement. By doing so, even if dust is present on the element surface, it is not transferred to the probe card, and there is an effect that it is possible to prevent the problem that dust or the like damages the element surface and frequently causes defects.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a membrane probe card according to an embodiment of the present invention.

2 (a) and 2 (b) are cross-sectional views showing a main part at the time of measurement in one embodiment of the present invention.

3 (a) and 3 (b) are sectional views showing a main part at the time of measurement of the second embodiment of the present invention.

FIG. 4 is a plan view showing the metal protrusion side of the probe card of the second embodiment.

FIG. 5 is a sectional view showing a conventional membrane probe card.

6 (a) and 6 (b) are cross-sectional views showing the main part of the membrane probe card of FIG. 5 during measurement.

FIG. 7 is a sectional view showing another example of a conventional membrane probe card.

8A and 8B are cross-sectional views showing the main part of the membrane probe card of FIG. 7 during measurement.

[Explanation of symbols]

 1a, 1b, 1c, 1d Wafers 2a, 2b, 2c, 2d Thin films 3a, 3b, 3c, 3d Insulating substrates 4a, 4b, 4c, 4d Metal protrusions 5a, 5b, 5c, 5d Semiconductor elements 6a, 6b, 6c, 6d Electrode pads 7a, 7b, 7c, 7d Conductor patterns 8a, 8b, 8c, 8d Translation bases 9a, 9b, 9c, 9d Leaf springs 10a, 10b, 10c, 10d Elastic bodies 11a, 11b, 11c, 11d Presser plate 12a, 12b, 12c, 12d axis fixed reference axis 13a, 13b, 13c, 13d axis 14a, 14b, 14c, 14d metal conductor layer

Claims (2)

(57) [Claims] 1. A thin film having a plurality of metal projections corresponding to electrode pads arranged on a semiconductor device under test formed on one surface of the thin film, and a thin film contacting the other surface of the thin film via an elastic body. In a probe card having a pressing plate for contacting and pressing the metal protrusion against the electrode pad, the pressing plate has the same external dimensions as the semiconductor device under test, and a lower surface that abuts the thin film. , A circular upper surface larger than the external dimensions of the semiconductor device under test, and an inner cylindrical shape
And a side surface, between the lower surface and the lower edge of the cylindrical side surface, the lower surface of the outer edge outward, probe card inclined surface extending obliquely upward is formed. 2. The probe card according to claim 1, wherein an inner portion of the thin film and the elastic body surrounded by a plurality of metal protrusions is opened.