JPH08194012A - Semiconductor element characteristic measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the contact resistance when measuring the characteristics by contacting the terminal electrodes on the wafer surface of the electrodes on the stage,
Reduce the error in the characteristic value. [Structure] The electrodes on the stage are made of conductive fiber, conductive resin,
Even if the wafer is warped, uniform contact resistance can be obtained by forming the conductive rubber so as to have flexibility and making the measuring needle stand on the surface of the wafer and easily deforming when pressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring characteristics of a semiconductor device having a vertical structure having electrodes on both main surfaces of a semiconductor substrate.

[0002]

2. Description of the Related Art In recent years, power semiconductor elements have been improved in output characteristics. In order to maximize its performance as a product, it is necessary to minimize the performance variation between chips. For that purpose, for example, the diameter 125 before being divided into 100 to 5000 chips is used.
The characteristic test in the condition of the mm wafer becomes very important. This is because the performance of the product is affected by selecting chips with the same performance with a minimum error. The power semiconductor device usually has a vertical structure in order to increase the current capacity. Therefore, a terminal electrode is also formed on the back surface of the wafer, and it is necessary to connect a measuring circuit to this terminal electrode at the time of measurement. For example, in the case of a transistor,
Place a measuring needle on the two terminal electrodes on the front surface of the wafer, and attach the terminal electrode on the back surface of the wafer, which is usually made of Al, to A on the stage.
The u-electrode is sucked and brought into close contact with the u-electrode for measurement.

In the power semiconductor element, a large current is passed through the contact surface between the back surface terminal electrode and the stage electrode.
If the contact resistance between them is large, a measurement error will occur. Therefore, in order to improve the contact between the backside electrode of the wafer and the stage electrode, as shown in FIG. 2, a special measuring needle is used to stand on the surface of the wafer 1 placed on the base (stage) 3, and a large measuring needle is used. A method of pressing the wafer 1 against the Au-plated electrode 2 on the surface of the stage 3 with a pressure of 5 is adopted. Further, the electrode 2 of the stage 3 having a good surface flatness is used.

[0004]

However, the above-mentioned conventional measuring method has the following problems. (1) Due to the large diameter of wafers and the sophistication of processes, warpage of wafers is increasing. (2) The thinning of the Al electrode on the backside of the wafer reduces the flexibility and reduces the cushioning effect.

For this reason, it becomes difficult to bring the back surface electrode of the wafer 1 into uniform contact with the stage electrode 2, and the pressure of 5
If you try to make the contacts larger by forcing them, the chips will be damaged. An object of the present invention is to solve the above-mentioned problems and to provide a semiconductor element having a stage electrode that can be brought into contact with the back surface electrode of the semiconductor element with a low contact resistance at the time of measurement in a wafer state before division into chips. It is to provide a characteristic measuring device.

[0006]

In order to achieve the above-mentioned object, the present invention is designed such that the element terminal electrodes on the back surface of the wafer are brought into contact with the electrodes on the surface of the base in the state of the wafer before being divided into chips. In a semiconductor device characteristic measuring device that measures the characteristic for each element region, the electrodes on the surface of the base are made of a material that is easily deformed by pressure. It is preferable that the easily deformable material is a conductive fiber individually fixed to the surface of the base. It is desirable that the conductive fiber be made of gold. The material that is easily deformable may be conductive resin or highly conductive rubber.

[0007]

When the electrode on the surface of the base is a flexible electrode made of conductive fiber, conductive resin, conductive rubber, etc., when measuring the device characteristics in the state of the wafer at the intermediate stage of semiconductor device manufacturing, When the terminal electrode of the element on the back surface of the wafer is brought into contact with the electrode on the base, the electrode is easily deformed, so that contact with low contact resistance is realized.

[0008]

1 is a sectional view common to the semiconductor device characteristic measuring apparatus of each embodiment of the present invention, and the same parts as those in FIG. 2 are designated by the same reference numerals. A flexible electrode 6 is formed on the metal stage 3 in the figure. This flexible electrode 6
When the wafer 1 is placed on it and pressure 5 is applied by the measuring needle 4, the wafer is easily deformed even with a small pressure, and even if the wafer has a warp, it comes into contact with a low contact resistance.

3 (a) and 3 (b) are enlarged views of a flexible electrode of a semiconductor device characteristic measuring apparatus according to an embodiment of the present invention.
On the surface of the base 3, gold fibers 61 formed by patterning a gold film formed by vapor deposition or sputtering by photoetching are concentrically attached. At this time, if the width of each gold fiber 61 is too large compared to the height, it is difficult for the gold fiber 61 to be deformed by the pressure. Therefore, it is desirable that the width be equal to or less than the thickness of the gold film. In another embodiment, the flexible electrode is made of a conductive resin such as silver paste or conductive rubber.

[0010]

According to the present invention, the following effects can be obtained by forming the base electrode of the device used for measuring the characteristics of the semiconductor element for electric power, etc. before chip division, from a material that is easily deformable. (1) There is no variation in contact resistance between the back electrode of the device and the base electrode, and the measurement accuracy is improved. As a result, variations in the characteristics of manufactured semiconductor devices were eliminated, and the characteristics were improved as a whole.

(2) The measurement margin error can be narrowed, the non-defective rate is improved, and the quality index can be established.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device characteristic device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional semiconductor device characteristic device.

3A and 3B show a flexible electrode portion of a semiconductor device characteristic measuring apparatus according to an embodiment of the present invention, where FIG. 3A is a sectional view and FIG.

[Explanation of symbols]

 1 Wafer 3 Stage 4 Measuring needle 6 Flexible electrode 61 Gold fiber

Claims (5)

[Claims] 1. In a wafer before being divided into chips, an electrode on a surface of a base is measured by contacting an element terminal electrode on the back surface of the wafer with an electrode on a surface of the base to measure characteristics of each element region. A device for measuring characteristics of a semiconductor device, wherein the device is made of a material that is easily deformed by pressure. 2. The device for measuring characteristics of a semiconductor element according to claim 1, wherein the easily deformable material is a conductive fiber individually fixed to the surface of the base. 3. The characteristic measuring device for a semiconductor element according to claim 2, wherein the conductive fiber is made of gold. 4. The semiconductor device characteristic measuring apparatus according to claim 1, wherein the easily deformable material is a conductive resin. 5. The semiconductor device characteristic measuring apparatus according to claim 1, wherein the easily deformable material is conductive rubber.