JPH1096746A - Small contact for high electric current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a greatly durable and small contact for high electric current, by allowing a contact of each freely-movable divided electrode to come into contact separately with an inspected electrode surface within a minimum contact area. SOLUTION: If a collector electrode with bipolar transistor as an inspected matter is placed on a lower electrode 1a on the upper surface of a lower electrode block 1, a divided electrode 2 installed in a robot arm is fallen through an electrode holder 3 or a bracket 6, and a tapered contact 2a of divided electrode 2 is brought into contact with the emitter electrode of the inspected matter on the electrode 1a, a flat contact end 2d of eight contacts 2a which have a contact face almost equal to area of an electrode face of the inspected matter comes into contact with whole face of the emitter electrode. A robot arm presses the contact 2a of divided electrode 2 on the electrode face of the inspected matter. The contact pressure of the contact 2a at this time is detected by a pressure sensor 7, and the robot arm controls it to keep a constant pressure, that is, to minimize the contact pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small contact for a large current used for measuring a semiconductor such as a switching element and a power transistor which is small and controls a large current.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a contact probe for conducting a withstand voltage test is provided with a point contact 20 having a tapered tip and attached to a holder 21 via a spring. Attached to a robot arm or the like (not shown), the tip of the point contact 20 is brought into contact with the emitter electrode of the bipolar transistor as the inspection object W via a spring pressure, and then a specified voltage is applied for a certain period of time to destroy the transistor. I was checking if I could endure without it. However,
In recent years, as the output of small switching elements and power transistors has been increased, the current flowing therethrough also becomes large. Therefore, the current flowing at the time of the electrical test also becomes large, and the point contact 20 has a large contact resistance. In addition, when a large current is applied, heat and discharge are generated, which makes it very difficult to carry out the inspection. In addition, the point contact 20 is greatly consumed by the heat and discharge, and the repetition life is extremely shortened. Therefore, it is conceivable to reduce the contact resistance by using a plurality of point contacts 20, but there is a problem that it is difficult to arrange the plurality of point contacts 20 because a small semiconductor electrode is small.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a small contact for a large current, which does not prevent the inspection from being performed due to heat generation or discharge, has good durability, and can be used for a long time. It is assumed that.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is to dispose a contact of a divided electrode which is divided into a plurality of pieces so as to be in contact with an electrode surface of an object to be inspected. 2. A small contact for a large current, wherein each divided electrode is movable so that each contact can individually contact an electrode surface of a test object, and a contact resistance is minimized with a minimum contact area.
In the invention of claim 1, a small contact for large current that controls the contact pressure of the contact based on the detection value of the pressure sensor is provided as the invention of claim 2, and is tapered at the tip of the divided electrode. A small contact for large current, wherein the contact end face of the contact is a flat plate is the invention of claim 3, and the contact end surface of the contact, whose contact pressure is controlled based on the detection value of the pressure sensor, is flat. The small contact for large current is defined as the invention of claim 4, and in the invention of claim 1 or 2 or 3 or 4,
A small contact for large current, wherein the divided electrodes are individually movable with the adjacent surfaces as guide surfaces, and the divided electrodes are urged toward the electrode surface of the inspection object via an elastic body. The invention of claim 5, claim 1 or 2 or 3 or 4
Also, in the invention of claim 5, a small contact for a large current, in which a sensing probe for measuring the resistance of the contact is built in the split electrode, is defined as the invention of claim 6, and the method of claim 1 or 2 or 3 or 4 or 5 or 6 is considered. In the invention, a small contact for a large current in which an inert gas region is formed between the contact and the electrode surface of the object to be inspected is the invention of claim 7.

[0005]

Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Reference numeral 1 denotes a lower electrode block having a lower electrode 1a for mounting an object to be inspected formed on an upper surface thereof. Above the lower electrode 1a of the lower electrode block 1, a tapered contact 2a that contacts an electrode surface of the object to be inspected. An electrode holder 3 for holding eight divided electrodes 2 formed at the tip is provided to be movable up and down. The divided electrode 2 is divided into a substantially triangular block shape at an angle of 60 °, and each movable separately as a guide surface between the electrode holder 3 and the divided electrode 2 and a mutually adjacent surface provided with a minute gap between each divided electrode. (Small tilt movement and vertical movement). On the lower surface at the center of the eight divided electrodes 2, a square block-shaped contact end face 2b having a smaller cross-sectional area than the cross-sectional area of the divided electrode 2 is formed into a flat plate shape.
The contacts 2a are protruded, and the contacts 2a are arranged in four rows in a row in which the right and left adjacent surfaces are in contact with each other, and two rows in which the front and rear adjacent faces are in contact with each other and are arranged in front and rear. And the maximum allowable contact surface (in this case, the contact between the electrode surface and the contact end surface covers substantially the entire surface). The allowable maximum contact surface refers to a minimum cross-sectional area of the divided electrode 2 in which heat and discharge do not occur due to an applied test voltage and current, and is to obtain a minimum contact resistance with a minimum contact area.

Reference numeral 4 denotes an elastic body such as rubber which is brought into contact with the upper surface of the divided electrode 2. The elastic body 4 has a contact 2a of each of the divided electrodes 2 adjacent to each other with a minute gap and which is located on the electrode surface of the inspection object. It is intended to be able to freely tilt or move up and down along the swell or tilt so that it can be in close contact. Reference numeral 5 denotes an insulating block fixed to the electrode holder 3, and the elastic body 4 is interposed between the lower surface of the insulating block 5 and the upper surface of the divided electrode 2.
Reference numeral 6 denotes a bracket fixed to the insulating block 5 and attached to a robot arm (not shown). The bracket 6 has a pressure sensor 7 attached thereto.
Based on the detection value of the pressure sensor 7, the pressing force of the robot arm against the object to be inspected, that is, the contact pressure of the contact 2a is controlled to be constant, and the contact resistance is controlled to be optimal.

[0008] Reference numeral 8 denotes a detection terminal attached to the divided electrode 2, and a test voltage is supplied through the terminal 8. 9 is a sensing probe attached to the divided electrodes 2, the sensing probe 9 is an emitter sensing electrode E ₁ formed on the object W through the through hole 2c to be Toru設the contacts 2a, the base sensing electrodes B ₁ and The contact is made with the base electrode B. Emitter sensing electrode E ₁ is intended to measure the time of large current testing, a small resistor having the divided electrodes 2. Reference numeral 10 denotes a gas chamber as an inert gas region filled between the divided electrode 2 and the lower electrode block 1 and filled with an inert gas. The gas chamber 10 is a lower edge of a cover 10a attached to the lower surface of the divided electrode 2. Is brought into close contact with the lower electrode block 1, and only the contact end face 2b of the contact 2a and the vicinity of the lower electrode 1a are made the minimum space for sealing. Reference numeral 11 denotes a gas inlet provided in the insulating block 5 for supplying an inert gas to the gas chamber 10, and reference numeral 12 denotes a supply passage for the inert gas provided through the insulating block 5, the elastic body 4, and the split electrode 2. . 1
Reference numeral 3 denotes a gas suction port provided in the lower electrode block 1. The gas suction port 13 sucks the atmosphere of the gas chamber 10 and suctions an inert gas from the gas injection port 11 to shorten the gas injection tact. Is what you do. 1
Reference numeral 4 denotes a gas suction passage provided on the upper surface of the lower electrode block 1, and reference numeral 15 denotes a plate for attaching the divided electrodes 2 to the electrode holder 3.

[0010] The device having such a structure is characterized in that the inspection object W is formed on the lower electrode 1 a formed on the upper surface of the lower electrode block 1.
The collector electrode C of the bipolar transistor is placed in contact with the lower electrode 1a, and the divided electrode 2 attached to a robot arm (not shown) is lowered via the electrode holder 3, the bracket 6, etc. Of the split electrode 2 on the emitter electrode E of the inspection object W
a, the flat contact end faces 2 of the eight contacts 2a having contact surfaces substantially equal to the area of the electrode surface of the inspection object W
b comes into contact with the entire surface of the emitter electrode E of the inspection object W. At this time, the cover 10a attached to the split electrode 2 is in contact with the upper surface of the lower electrode block 1, and a gas chamber 10 as a small inert gas region is formed between the cover 10a and the lower electrode block 1. Is done. When the gas chamber 10 is formed in this manner, an inert gas is supplied from the gas inlet 11 provided in the insulating block 5 and the gas inlet 1 of the lower electrode block 1 is supplied.
3, the suction pressure is applied to the gas chamber 10 through the gas suction passage 14 of the lower electrode 1a, and the air in the gas chamber 10 is rapidly sucked and the supply passage 1
The inert gas is supplied to the gas chamber 10 through 2, and the inside of the gas chamber 10 is filled with the inert gas in a short time.

Then, the contact 2a of the divided electrode 2 is pressed against the electrode surface of the inspection object W by the robot arm. The contact pressure of the contact 2a at this time is detected by the pressure sensor 7 provided on the bracket 6, and is controlled by the robot arm so that the pressure is always constant, that is, the contact resistance is minimized. In this manner, the contact 2a is pressed against the electrode surface of the inspection object W. If the surface of the electrode surface has a slight inclination or undulation, the contact 2a is pressed according to the inclination or undulation of the electrode surface.
Since each of the divided electrodes 2 is slightly inclined through the elastic body 4 and a minute gap as an adjacent surface, or moves up and down so that the contact surface between the electrode surface and each contact 2a is maximized,
The contacts 2a are contacted with a uniform pressure over substantially the entire surface of the electrode surface of the inspection object W and contact with a minimum contact resistance, and the contact resistance of each contact 2a is reduced to 1 / divided number. For this reason, when the voltage for inspection is applied to the contact 2a, the current does not flow to one place and generate heat, and the inspection object W is not damaged due to electric discharge. Then, when a large current test, the sensing probe 9 is in contact with the emitter sensing electrode E ₁ through the through hole 2c that is Toru設split electrode 2, to measure the voltage drop due to the resistance division electrode 2. Based on this measured value, an accurate specified voltage is applied between the emitter and the collector of the inspection object W by adding an applied voltage that compensates for a voltage drop caused by the resistance of the divided electrode 2 during the withstand voltage test. I have to. In the preferred embodiment, the divided electrode 2 is divided into eight, but the number is not limited to eight, and it is needless to say that the divided electrode 2 may be divided into two to ten or more. In a preferred embodiment, the contact 2a
Is in contact with almost the entire electrode surface of the inspection object W, but it is sufficient that a contact area of 50% or more can be obtained according to the applied voltage or current.

[0010]

According to the present invention, as is apparent from the above description, the contact of the divided electrode, which is divided into plural parts and can be individually moved, is brought into contact with the electrode surface of the inspection object. , The contact resistance of each contact becomes 1 / divided number. In addition, each contact can be individually and securely adhered to the electrode surface according to the inclination or undulation of the electrode surface of the inspection object, so that the contact resistance can be reduced, and the current flows intensively and generates heat. And no discharge occurs, so that damage to the inspection object can be prevented. If the pressure sensor controls the contact pressure of the contact to be constant, an optimum contact resistance can be always obtained. And
If the contact end surface of the contact is made flat, the strength of the contact can be increased, so that sufficient contact pressure for minimum contact resistance can be applied and the electrode surface of the inspection object is damaged. There is no. In addition, since the tapered contacts are projected from the split electrodes, even if the split electrodes attached to the electrode holder are large, multiple contacts can be reliably formed on the small electrode surface of the inspection object. Can be contacted. In addition, by urging the divided electrodes through the elastic body, the divided electrodes can be individually slightly tilted or vertically moved, so that the contact end surfaces of the respective contacts can be brought into surface contact, and the contact resistance can be minimized. It can be. In addition, if the sensing probe is built in the split electrode, the voltage drop due to the resistance of the split electrode can be corrected without increasing the size of the device. Furthermore, by forming an inert gas region only on the contact and the electrode surface of the object to be inspected, it is possible to prevent a discharge which is likely to occur when a large current is applied, and furthermore, only the contact end surface and the electrode surface of the object to be inspected are formed. By forming an inert gas region, the volume of the gas chamber can be minimized, the amount of gas used can be saved, and the tact time of gas injection at the time of replacing the inspection object can be greatly reduced. Therefore, the present invention greatly contributes to the development of the industry as a small contact for a large current that solves the conventional problems.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a preferred embodiment of the present invention.

FIG. 2 is a partially cutaway plan view showing a preferred embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view showing a divided electrode according to a preferred embodiment of the present invention.

FIG. 4 is a perspective view showing a bipolar transistor as an inspection object.

FIG. 5 is a partially cutaway front view showing a conventional contact probe.

[Explanation of symbols]

 2 Split electrode 2a Contact 2b Contact end face 4 Elastic body 7 Pressure sensor 10 Sensing probe

Claims (7)

[Claims] A contact of a divided electrode (2) divided into a plurality of parts
(2a) is arranged so as to be in contact with the electrode surface of the object to be inspected, and each of the divided electrodes (2a) is so arranged that each contact (2a) of the divided electrode (2) can individually contact the electrode surface of the object to be inspected. ) Is movable, and the contact resistance is minimized with the smallest contact area. 2. The small contact according to claim 1, wherein the contact pressure of the contact is controlled based on a value detected by the pressure sensor. 3. The small contact for large current according to claim 1, wherein the contact end face (2b) of the contact (2a) tapered at the tip of the split electrode (2) is formed in a flat plate shape. 4. The small contact for high current according to claim 1, wherein the contact end face (2b) of the contact (2a) whose contact pressure is controlled based on the detection value of the pressure sensor (7) is flat. . 5. The divided electrodes (2) are individually movable with the adjacent surfaces as guide surfaces, and the divided electrodes (2) face the electrode surface of the inspection object via the elastic body (4). 5. The small contact for a large current according to claim 1, wherein the contact is energized. 6. A large current sensor according to claim 1, wherein a sensing probe (10) for measuring a voltage drop due to the resistance of the contact (2a) is incorporated in the split electrode (2). Small contact. 7. The small contact for a large current according to claim 1, wherein an inert gas region is formed between the contact (2a) and the electrode surface of the object to be inspected.