JPH09252033A - Semiconductor measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure wafer or chip conditions by dividing an electrode jig contacted to the back of a semiconductor element into a force part and sense part which are interdigitally disposed. SOLUTION: An electrode jig 1 is composed of a sense part 2 and force part 3, each having grooves 6 on the surface and both parts are formed into interdigitally combined comp shapes. Such interdigital structure of the part 2 for detecting a voltage and the part 3 for detecting a current prevent the dispersion of the contact resistance and enables an accurate measurement of the wafer or chip conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor measuring apparatus used for measuring the characteristics of a vertical semiconductor device, and particularly for measuring in a wafer state or a chip state before assembly.

[0002]

2. Description of the Related Art A so-called vertical semiconductor element having electrodes on the upper and lower surfaces of a semiconductor substrate and allowing a current to flow in the vertical direction is a structure particularly suitable for large current applications and is widely used as a large capacity semiconductor element. Before assembling the vertical semiconductor device, the characteristics are measured in a wafer state or a chip state to be selected and then assembled. FIG. 9A is a cross-sectional view of a conventional measuring device in a chip state, and FIG. 9B is a plan view of an electrode jig that contacts the back surface of the wafer.

In FIG. 9A, the chip 4 is placed on the electrode jig 1 and is sucked and fixed from the vacuum outlet 5 of the electrode jig 1. An electrode 7 is provided on the upper surface of the chip 4, and a sense needle 8 for voltage detection and a force needle 9 for current detection are in contact with each other. In FIG. 9 (b),
It can be seen that the electrode jig 1 is also divided into a voltage sensing section 2 and a current sensing force section 3. The chips 4 are placed so as to contact both sides. The reason why the sense portion 2 and the force portion 3 are divided and the so-called Kelvin connection is performed is to avoid contact resistance between the back surface of the chip 4 and the electrode jig 1.

[0004]

A large number of chips (20 to 1500) are formed on a wafer, and the conventional characteristic check in the wafer state or the chip state is as follows regarding contact conditions to the back surface of each chip. It includes instability factors such as. 1) Variation in contact resistance between chip back surface and electrode jig 2) Variation in vacuum suction force on electrode jig 3) Variation in contact area between chip back surface and force part, sense part electrode jig 4) Contact at force part Variation in distance from a point (when the specific resistance of the electrode jig is large) In the conventional method as shown in FIG. 9, since the force portion and the sense portion have only one place and are in contact with each other only partially, The contact resistance was too high to measure accurately.

FIG. 5 is a relationship diagram of the saturation voltage before and after the assembly of the bipolar transistor. An example measured by the conventional method of FIG. 9 is shown by □. The horizontal axis is the saturation voltage in the chip state before assembly, and the vertical axis is that after assembly. The saturation voltage is lower after assembly. That is, the measured value in the chip state does not show a true value. Also, the variation is large.

As described above, in the static characteristic measurement (saturation voltage, voltage drop) of the vertical semiconductor device, the contact resistances cannot be accurately measured because of variations in contact resistance, and as a result, accurate determination can be made only after assembly. . In view of the above problems, an object of the present invention is to provide a measuring device that can perform accurate measurement in a wafer state or a chip state.

[0007]

In order to solve the above problems, in the semiconductor measuring device of the present invention, the electrode jig which is in contact with the back surface of the semiconductor element is divided into a force part and a sense part, which are arranged intricately. Be present. In particular, it is assumed that the electrode jigs of the force portion and the sense portion are in the shape of comb teeth which are engaged with each other.

By doing so, the contact resistance on the back surface of the semiconductor element can be reduced. Further, at least the surface of the electrode jig in the force portion has, for example, groove-shaped irregularities. By doing so, an ideal contact can be realized by vacuuming the concave portion and providing a convex electrode contact.

The area of the force portion of the electrode jig is larger than that of the sense portion. By thus widening the contact area, it is possible to prevent the current density from becoming excessive when a large current is passed. Also, a vacuum outlet may be provided in the sensing portion of the electrode jig. By doing so, good contact with the sense portion, which requires a reduction in contact resistance, becomes good.

It is assumed that the force part and the sense part of the electrode jig are arranged in concentric circles intricately interdigitated with each other, and the vacuum outlets are arranged in concentric circles. By doing so, it is suitable for measurement in a circular wafer state, and the contact resistance can be suppressed at any part of the chip in the wafer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings in which the same parts as those in FIG. [Embodiment 1] FIG. 4 is a plan view of an electrode jig of a semiconductor measuring apparatus according to the first embodiment of the present invention.

In FIG. 4, the sense unit 2 and the force unit 3
And are processed into a comb-like shape that is intricate with each other. The size is about 50 × 50 mm ² . A vacuum outlet 5 is opened in the sensing portion 2 in the central portion of the electrode jig. Therefore, the sense portion 2 for voltage detection and the back surface of the chip 4 come into contact with each other at many points, and the contact resistance can be significantly reduced.

Since the area of the force part 3 of the electrode jig is larger than that of the sense part 2 and the contact area is large, it is possible to prevent the current density from becoming excessive when a large current is passed. Furthermore,
Gold plating on the surface of the electrode jig enables more stable measurement. The shape of the comb teeth may be such that the force portion 3 is thick and the sense portion 2 is thin. The root may be thick and the tip may be thin.

Further, the comb teeth may be arranged in an island shape and three-dimensionally cross each other. [Embodiment 2] FIG. 1 is a plan view of an electrode jig of a semiconductor measuring apparatus according to a second embodiment of the present invention, which can be said to be a modification of the first embodiment. The electrode jig 1 includes a sense section 2 and a force section 3. Hatching on the surface of the sense part 2 means that the groove 6 is formed on the surface. Although the groove 6 is formed on the surface of the force portion 3, only the sense portion 2 is hatched in order to avoid making the drawing complicated.

FIG. 2 is an enlarged view of the central portion of FIG. Both sides of the sense part 2 are force parts 3, and grooves 6 having a width of 0.2 mm and a depth of 0.3 mm are dug vertically and horizontally on the surfaces of both parts. An opening of the vacuum suction port 5 can be seen in the sense unit 1. In this example, the sense portion 2 and the force portion 3 are intricately processed in the same manner as in the first embodiment of FIG. 1, and further, the surface of the sense portion 2 and the force portion 3 is made uneven. As a result, not only the number of contact points is increased, but also vacuuming is improved and the contact resistance can be further reduced.

FIG. 3 is a sectional view taken along the line AA 'of the semiconductor measuring device using the electrode jig shown in FIG. The grooves 6 on the surface of the sense portion 2 and the force portion 3 of the electrode jig 1 can be clearly seen.
Because of the groove 6, the chip 4 and the electrode jig 1 are in contact with each other at multiple points. Reference numeral 7 is an upper electrode provided on the chip 4, 8 is a sense needle, and 9 is a force needle. In FIG.
The relationship between the saturation voltage of the bipolar transistor measured by the semiconductor measuring device of FIG. 4 and that after assembly is also shown. This example is shown by ●. In this case, the saturation voltage after assembly is about 0.5 V higher than the measured value in the chip state. Also, the variation is small. As a result of investigation, it was found that the increase of 0.5V was due to wire bonding. Therefore, the measured values in the chip state are reliable,
If the semiconductor measuring device of FIG. 1 is used, the measurement accuracy will be greatly improved.

As described above, since accurate measurement can be performed in a chip state or a wafer state, accurate selection can be performed, and the number of assembling steps can be reduced, leading to cost reduction. In addition, feedback to improve the characteristics becomes faster. [Embodiment 3] FIG. 6 is a plan view of an electrode jig of a semiconductor measuring apparatus according to a third embodiment of the present invention. Two vacuum outlets 5 are provided. By providing a large number of vacuum outlets 5 in this manner, the number of contact points between the chip 4 and the electrode jig 1 increases, and the contact resistance can be reduced. [Embodiment 4] FIG. 7 is a plan view of an electrode jig of a semiconductor measuring apparatus according to a fourth embodiment of the present invention, which is suitable for measurement in a wafer state.

In the fourth embodiment, the electrode jig 1 having a diameter of about 170 mm is used for a 6-inch wafer, depending on the diameter of the wafer. The electrode jig 1 that is in contact with the back surface of the chip 4 is configured by convolving the sense portion 2 and the force portion 3 that are concentrically divided. Reference numeral 11 is an insulator embedded between the sense portion 2 and the force portion 3. The vacuum outlet 5 is provided at the center. In order to improve the adsorption between the wafer and the electrode jig 1, a width of 1 mm on the surface of the electrode jig 1,
The vacuum groove 10 having a depth of 0.5 mm is formed. This improves the vacuum state on the entire wafer and enables accurate measurement. [Embodiment 5] FIG. 8 is a plan view of an electrode jig of a semiconductor measuring apparatus according to a fifth embodiment of the present invention, which is also suitable for measurement in a wafer state.

In the fifth embodiment, the chip 4 is composed of the sense portion 2 and the force portion 3 which are concentrically divided.
The electrode jig 1 is in contact with the back surface of the. Sense part 2
Grooves 6 are engraved on the surfaces of the and force portions 3. However, unlike the fourth embodiment, the sense portion 2 is provided with a large number of vacuum outlets 5 having a diameter of 1 mm. As a result, the number of contact points between the chip 4 and the electrode jig 1 increases at any part on the wafer. In particular, even in the case of a warped wafer, the contact resistance can be reduced and accurate measurement can be performed.

[0020]

As described above, according to the present invention, in a measuring apparatus for a vertical semiconductor element used as a large-capacity semiconductor, a voltage detecting sense section of an electrode jig and a current detecting force section are combined. By arranging in an elliptical
We have made possible a measuring device that can prevent the contact resistance from fluctuating and perform accurate measurement in the wafer state or the chip state.

Since accurate measurement can be performed in a wafer state or a chip state, accurate selection can be performed, and the number of assembling steps can be reduced, leading to cost reduction.

[Brief description of drawings]

FIG. 1 is a plan view of an electrode jig of a measuring device according to a second embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG. 1;

FIG. 3 is a sectional view of a measuring apparatus according to a second embodiment of the present invention.

FIG. 4 is a plan view of an electrode jig of the measuring apparatus according to the first embodiment of the present invention.

FIG. 5: Comparison diagram of saturation voltage before and after assembly of bipolar transistor

FIG. 6 is a sectional view of a measuring apparatus according to a third embodiment of the present invention.

FIG. 7 is a plan view of an electrode jig of a measuring device according to a fourth embodiment of the present invention.

FIG. 8 is a plan view of an electrode jig of a measuring device according to a fifth embodiment of the present invention.

9A is a sectional view of a conventional measuring device, and FIG. 9B is a plan view of an electrode jig.

[Explanation of symbols]

 1 Electrode jig 2 Sense part 3 Force part 4 Semiconductor chip 5 Vacuum suction port 6 Groove 7 Upper electrode 8 Sense needle 9 Force needle 10 Vacuum groove 11 Insulator

Claims (7)

[Claims] 1. An apparatus for measuring characteristics of a vertical semiconductor element, wherein an electrode jig contacting the rear surface of the semiconductor element is divided into a force portion and a sense portion in order to reduce contact resistance on the rear surface of the semiconductor element. A semiconductor measuring device characterized in that they are arranged intricately with each other. 2. The semiconductor measuring device according to claim 1, wherein the electrode jigs of the force portion and the sense portion are in the shape of comb teeth which are engaged with each other. 3. The semiconductor measuring device according to claim 1, wherein at least the surface of the electrode jig of the sensing portion has irregularities. 4. The semiconductor measuring device according to claim 1, wherein the area of the force portion of the electrode jig is larger than that of the sense portion. 5. The semiconductor measuring device according to claim 1, wherein a vacuum outlet is provided in the sensing portion of the electrode jig. 6. The semiconductor measuring device according to claim 1, wherein the force part and the sense part of the electrode jig are arranged in a concentric circle shape intricately interdigitated with each other. 7. The semiconductor measuring device according to claim 6, wherein the vacuum outlets are arranged concentrically.