JP2001108707A - Probe guard device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe card device capable of performing satisfactory characteristic inspection, by preventing contact failure between a probe pin and an IC pad due to spring deterioration with a simple structure. SOLUTION: Contact pressure between a needle 13b and an IC 21 is relieved and adjusted by causing stretching deflection evenly in 2 directions perpendicular to a pressing direction by an S-shaped spring 13c elastically holding the needle 13b against a pressing force applied when a probe pin 13 is brought into contact with an IC pad 22 provided on the IC 21. Also, by bringing a tip of the needle 13b into contact with the IC pad 22 at a predetermined tilt angle thereto, an insulation film formed on a surface of the IC pad 22 is satisfactorily peeled off, so that the electrical resistance between the probe pin 13 and the IC pad 22 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe guard device used for inspecting electrical characteristics and the like of a semiconductor integrated circuit device.

[0002]

2. Description of the Related Art In recent years, as semiconductor integrated circuits (hereinafter, abbreviated as ICs) have become multifunctional and have higher densities, the importance of characteristic tests and reliability tests has further increased. Hereinafter, an IC inspection process at the wafer stage will be described with reference to FIGS. As shown in FIG. 4A, on a silicon wafer 20, a plurality of ICs 21 each having an element for realizing a predetermined function are formed. Each IC 21
As shown in FIG. 4 (b), it generally includes an element forming region 21b provided substantially at the center of the die 21a, and a pad forming region 21c provided around the die 21a.

[0005] As shown in FIG. 5, such an IC 21 is mounted and held on a stage 31 of a wafer prober 30 in a state of a silicon wafer 20, and is mounted on a test head (not shown) facing the stage. The probe guard 10 is electrically connected to each IC 21. Then, the IC 21 responds to the test signal applied from the IC tester (measuring device) 32 through the distribution cable 33.
A characteristic test has been performed by evaluating the output signal from the computer.

Here, a vertical probe guard will be described as an example of the probe guard 10 with reference to FIG. As shown in FIG. 6A, the vertical probe guard 10
A is an insulating probe guard substrate 11A, a pin holding portion 12A provided on one surface (lower surface) of the probe guard substrate 11A, a probe pin (group) 13A vertically protruding from the pin holding portion 12A, and a probe. And a wiring layer 14 provided on the other surface (upper surface) side of the guard substrate 11. The one end of the wiring layer 14 is connected to an IC tester 32 via a wiring cable 33 as shown in FIG.
It is connected to the.

As shown in FIG. 6B, the pin holding section 12A houses a probe pin 13A formed of a material such as tungsten copper, and an IC pad and a probe pin 13A provided in an IC pad formation region. According to the pressing force applied at the time of contact with the probe pin 13A, a receiving hole 15A for slidingly holding the probe pin 13A, and the probe pin 13A is stored in the receiving hole 15A, and one end side of the probe pin 13A and the probe guard substrate 11A side. U-shaped spring 1 interposed between
6A. The probe pin 13A is shown in FIG.
As shown in (c), they are arranged so as to correspond to the arrangement of the IC pads 22 provided on the IC 21 to be inspected. The probe guard substrate 11A side of the U-shaped spring 16A is connected to the wiring layer 14A on the upper surface of the probe guard substrate 11A.

[0006] Such a probe guard 10A is shown in FIG.
7A is mounted on the test head of the wafer prober 30 shown in FIG.
3A is pressed against the IC pad 22 on the IC 21 by a pressing force (arrow FA) applied to the pin holding portion 15.
When the U-shaped spring 16A provided in A flexes elastically, the probe pin 13A moves up and down, and the contact pressure between the probe pin 13A and the IC pad 22 is kept good. At this time, probe pin 1
The contact state between the tip of 3A and the IC pad 22 is a point contact state according to the elastic force of the U-shaped spring 16A because the probe pin 13A is pressed vertically on the upper surface of the IC pad 22.

[0007]

As described above, the conventional probe guard device has a configuration in which a probe pin electrically contacting an IC pad is elastically held by a U-shaped spring. Therefore, it has the following problems. (1) With the increase in the number of input / output terminals and the miniaturization of IC pads accompanying the increase in the integration density of ICs, the miniaturization and narrowing of the probe pins are progressing, and the springs holding the probe pins also need to be miniaturized. Have been. Therefore, elastic fatigue and deterioration of the spring due to repetition of the inspection work become remarkable.

In particular, as shown in FIG. 8 (a), when a U-shaped spring 16A is employed, there is an advantage that the shape is simple and suitable for miniaturization, but there is one expansion and contraction deflection against the pressing force (arrow FA). Because it is biased in the direction (arrow DA),
The deterioration of the U-shaped spring 16 causes the probe pin 1
The holding balance of 3A is not equal, and FIG.
As shown in (b), there is a problem that the tip position of the probe pin 13A gradually shifts (arrow PA) and eventually comes off the IC pad 22 to cause a contact failure or damage to a peripheral circuit (circuit element). ing.

(2) Due to the structure projecting perpendicular to the probe guard substrate, the contact state between the probe pin and the IC pad is limited by the elastic force of the U-shaped spring as shown in FIG. With the corresponding contact pressure, the probe pin is in a point contact state in which the probe pin is vertically pressed against the upper surface of the IC pad. On the other hand, as shown in FIG.
On the second surface, a thin metal oxide film (insulating film) 23 formed by oxidation of the pad material is formed, and good electrical connection between the probe pin 13A and the IC pad 22 cannot be obtained as it is. As shown in FIGS. 9B and 9C, by pressing the probe pin 13A against the upper surface of the IC pad 22, the metal oxide film 23 is peeled off in a very narrow point region 23A to obtain an electrical connection. Can be

However, in such an electrically connected state in the point region 23A, the electric resistance increases,
The input / output signal to the IC 21 changes or becomes unstable,
There is a problem that accurate characteristic inspection and evaluation cannot be performed. Further, since the contact state between the probe pin 13A and the IC pad 22 depends on the contact pressure according to the elastic force of the U-shaped spring 16A, accurate contact depending on the elastic fatigue or deterioration state of the U-shaped spring 16A. There is a problem that the characteristic inspection cannot be performed.

As a shape of the spring for supporting the probe pin, a configuration using a coiled spring is known, as described in JP-A-2-38864, JP-A-8-97260 and the like. ing. On the other hand, as described above, miniaturization of IC pads and probe pins has been required with an increase in the integration density of ICs. For example, in recent years, for example, the diameter of a probe pin is 80 μm, and the inner diameter of a storage hole is 84 μm.
m, and the pitch between the pins is set to about 150 μm. Therefore, it is extremely difficult to manufacture a minute coil spring by processing an elastic metal material corresponding to such minute dimensions. Has become. Therefore, there is a demand for the development of a probe guard device that can maintain a good contact state for a long time with a simple configuration.

In view of the above problems, the present invention provides a probe guard capable of preventing a contact failure between a probe pin and an IC pad due to deterioration of a spring with a simple configuration and performing a good characteristic test. It is intended to provide a device.

[0013]

According to a probe guard device of the present invention, a pressing force applied when a probe pin is brought into contact with a pad of a semiconductor integrated circuit is two-dimensionally bent by an S-shaped spring or the like. The elastic member having the above-mentioned structure absorbs evenly in a plurality of directions, and makes the tip of the probe pin contact the pad at a predetermined angle. for that reason,
ADVANTAGE OF THE INVENTION According to the probe guard apparatus which concerns on this invention, while the pressing force applied when making a probe pin contact a pad is absorbed equally in the direction perpendicular | vertical to a pressing force by an elastic member, the probe which contacts incliningly By the tip of the pin,
Peel the thin insulating film on the pad surface over a wide area,
The contact area between the probe pin and the pad is increased, and the contact state is stabilized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the probe guard device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of a probe guard applied to a probe guard device according to the present invention. Here, the probe guard according to the present embodiment is:
It is favorably applied to a probe guard device having a configuration equivalent to that shown in the prior art (see FIG. 5). FIG. 1 (a)
As shown in FIG.
Are a probe pin (group) 13 fixed to the lower surface side of the insulating probe guard substrate 11 by the fixing member 12, and a wiring layer 14 formed on the upper surface side of the probe guard substrate 11.
, And is configured. Although not shown, one end of the wiring layer 14 is connected to the IC tester 32 via the wiring cable 33 as in the case shown in FIG.

As shown in FIG. 1B, the probe pins 13 are vertically protruded from the lower surface of the probe guard board 11, and are pin-fixed by a fixing member 12 such as a resin material. It is composed of a needle 13b whose base is housed in the pin guide 13a, and an S-shaped spring (elastic member) 13c housed in the pin guide 13a and elastically holding the base of the needle 13b and the probe guard board 11. I have. Here, the probe pin 13 is, as shown in FIG.
The IC pads 22 are arranged so as to correspond to the arrangement of the IC pads 22 provided thereon. The pin guide 13a is formed of, for example, a cylindrical insulating member, and the base of the needle 13b extends in the extending direction of the pin guide 13a (the probe guard substrate 1).
(In the direction perpendicular to 1).

The needle 13b is made of, for example, tungsten copper, and is accommodated and held in the pin guide 13a, and a tip portion bent and formed with an inclination angle of, for example, 167 ° with respect to the base. It is composed of S
The C-shaped spring 13c is made of a material having excellent electrical conductivity while having elasticity, and is interposed between the base of the needle 13b and the probe guard board 11 inside the pin guide 13a to elastically move the needle 13b. To be held. The probe guard substrate 11 side of the S-shaped spring 13 is taken out to the upper surface side of the probe guard substrate 11 through a conductive layer penetrating the probe guard substrate 11 or wiring, and is connected to the wiring layer 14 by, for example, soldering.
It is connected to the. That is, the needle 13b is electrically connected to an IC tester (not shown) via the S-shaped spring 13 and the wiring layer 14.

Next, an operation state of the probe pins when an electrical characteristic test is performed using the probe guard having the above-described configuration will be described with reference to the drawings. FIG. 2 is a schematic diagram illustrating the operation mechanism of the probe guard applied to the present embodiment. In the probe guard having the above-described configuration, as shown in FIG.
In a state where the probe pin 13 is not in contact with C21, that is, at the time of non-inspection, the S-shaped spring 13c
Is in a free length state, and the needle 13b is in a state of protruding most from the pin guide 13a.

On the other hand, at the time of inspection, as shown in FIG. 2B, the program guard 10 is pushed down in the direction of the silicon wafer 20 on the chuck 31 (arrow F), and the tip of the needle 13b becomes the inspection target. IC21 has become
Contact As a result, the base of the needle 13b moves so as to be pushed into the pin guide 13a, and in two arch portions on the left and right sides constituting the S-shaped spring, two directions perpendicular to the compression direction (arrow G) ( Arrow D
R, DL), the contact pressure applied between the tip of the needle 13b and the IC 21 is moderately adjusted, and the elastic fatigue and deterioration of the S-shaped spring 13c are suppressed.

In this state, the needle 13
Since the tip of the needle 13b formed by bending at a predetermined angle with respect to the base of the needle b contacts the IC 21 at an angle, the tip of the needle 13b is bent and pushed up (arrow B). ) Also reduces the pressing force applied to the S-shaped spring 13c,
The contact pressure between the tip of the needle 13b and the IC 21 is appropriately adjusted. Then, while maintaining such a contact state, a predetermined test signal for characteristic inspection is applied from an IC tester (not shown), and an output signal is obtained.
The quality of the IC is evaluated.

As described above, the expansion and contraction of the S-shaped spring 13c occurs evenly in the direction (arrows DR and DL) perpendicular to the pressing direction (arrow F).
By adding the deflection (arrow B) at the tip of 3b, the pressing force applied to the S-shaped spring 13c is reduced, so that the elastic fatigue and deterioration of the S-shaped spring 13b due to the repetition of the inspection work. Greatly suppressed,
The holding balance of the probe pin 13 is properly maintained, and the movement (shift) of the contact position of the tip of the needle 13b can be prevented. Therefore, it is possible to prevent the contact position of the tip portion of the needle 13b from coming off the IC pad and damaging the circuit element in the circuit forming area.

Next, the state of contact between the tip of the needle and the IC pad during the above-described inspection will be described with reference to the drawings. FIG. 3 is a schematic diagram showing a contact state between the tip of the needle and the IC pad in the probe guard applied to the present embodiment. At the time of non-inspection of the IC, as shown in FIG. 3A, the tip of the needle 13b is in contact with the IC pad 22 provided on the IC 21.
They are arranged with a predetermined inclination angle. Here, as shown in the prior art, a thin metal oxide film 23 formed by oxidizing the pad material is formed on the upper surface of the IC pad 22.
Are formed.

At the time of IC inspection, FIG.
As shown in (b) and (c), immediately after the tip of the needle 13b comes into contact with the IC pad 22 (indicated by a two-dot line in the drawing), a predetermined pressing state (corresponding to FIG. 2 (b)) In this state, the upper surface of the IC pad 22 is moved by contact (arrow M) until the metal oxide film 23 is peeled off along the movement trajectory 13a of the tip of the needle 13b.
Therefore, the tip of the needle 13b and the IC pad 22
The contact state with the metal oxide film 23 is made by pressing the probe pin 13A vertically, as shown in the prior art.
Is not a point contact state where only a minute point area 23A is peeled off, but a surface contact state (or a line contact state) in a relatively large area where the metal oxide film 23 is completely peeled off along the upper surface of the IC pad 22. As a result, the electrical resistance can be sufficiently reduced, and an accurate and proper inspection can be realized without causing a change in the inspection signal even in the electrical characteristic inspection.

In the above-described embodiment, the case where the S-shaped spring 13c is applied as the elastic member interposed between the base of the needle 13b and the probe guard substrate 11 has been described. The present invention is not limited to this, and may be, for example, a spring having a shape in which a "-" shape is continuous. In short, if the probe pin has a two-dimensionally bent structure so that the pressing force applied to the probe pin can be evenly absorbed in a direction perpendicular to the pressing direction, another configuration is used. You may have.

Further, in the above-described embodiment, the tip of the needle 13b is set at one point with respect to the base of the needle 13b.
Although the case where the probe pin bent at 67 ° is applied has been described, it goes without saying that the present invention is not limited to this inclination angle. That is, at the time of contact with the IC pad, the tip of the needle bends to reduce a part of the pressing force.
As long as the metal oxide film (insulating film) on the upper surface of the pad can be sufficiently peeled off to realize a good connection state, it may have another bending angle (inclination angle). Further, in the above-described embodiment, one IC 21 formed on the silicon wafer 20 is inspected by the probe pins (group) 13 protruding from the probe guard 10.
Although the case of electrical connection has been described, it is needless to say that a plurality of ICs formed on the silicon wafer 20 may be tested and simultaneously connected and tested. .

[0025]

According to the first or second aspect of the present invention, the pressing force applied when the probe pin is brought into contact with the pad of the semiconductor integrated circuit is bent two-dimensionally, such as an S-shaped spring. With the elastic member having the above-mentioned structure, the contact pressure between the probe pin and the semiconductor integrated circuit can be satisfactorily reduced and adjusted. Elastic fatigue and deterioration are suppressed. Therefore, an elastic member having a shape that can be simplified and reduced in size, such as an S-shaped spring, can evenly generate expansion and contraction deflection with respect to the pressing force. In addition, it is possible to suppress displacement of the tip position of the probe pin due to fatigue and deterioration of the elastic member, prevent poor contact with the pad and damage to the circuit element, and realize a highly reliable characteristic test. .

According to the third aspect of the present invention, the tip of the probe pin is formed to have a predetermined angle with respect to the pad, and is contacted at an angle to the pad. When the pad is brought into contact with the pad, the thin insulating film formed on the pad surface is peeled over a wide area, so that the contact area between the probe pin and the pad can be increased and a stable contact state can be realized. Therefore, the electrical resistance between the probe pin and the pad can be sufficiently reduced, and an accurate and proper inspection can be realized without causing a change in the inspection signal in the characteristic inspection.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a probe guard applied to a probe guard device according to the present invention.

FIG. 2 is a schematic diagram illustrating an operation mechanism of a probe guard applied to the embodiment.

FIG. 3 is a schematic diagram showing a contact state between a tip portion of a needle and an IC pad in a probe guard applied to the embodiment.

FIG. 4 is a schematic diagram of an IC formed on a silicon wafer.

FIG. 5 is a conceptual diagram showing a schematic configuration of a conventional probe guard device.

FIG. 6 is a schematic configuration diagram showing an example of a conventional probe guard.

FIG. 7 is a schematic diagram illustrating an operation mechanism of a conventional probe guard.

FIG. 8 is a schematic view showing a first problem of the conventional probe.

FIG. 9 is a schematic view showing a second problem of the conventional probe.

[Explanation of symbols]

10 probe guard, 11 probe guard board, 12 fixing member, 13 probe pin, 14
... wiring layer, 13a ... pin guide, 13b ... probe pin, 13c ... S-shaped spring, 20 ... silicon wafer, 21 ... IC, 22 ... IC pad, 23 ...
Metal insulating film, 30 Wafer prober

Claims (3)

[Claims] 1. A probe guard device for inspecting predetermined electrical characteristics by bringing a probe pin into contact with a pad on a semiconductor integrated circuit device, wherein an elastic member having a two-dimensionally bent structure is provided at a base of the probe pin. A probe guard device, wherein a pressing force applied to the probe pin when the probe pin is brought into contact with the pad is evenly absorbed in a predetermined direction perpendicular to the pressing force. 2. The apparatus according to claim 1, wherein the elastic member is an S-shaped spring, and absorbs a pressing force applied to the probe pin evenly in two directions perpendicular to the pressing force. The probe guard device according to claim 1, wherein 3. The probe guard according to claim 1, wherein a tip portion of the probe pin is formed at a predetermined angle with respect to the pad, and contacts the pad at an angle. apparatus.