JPH08184639A - Contactor structure - Google Patents

Abstract

PURPOSE: To feed a power device with a high current at high rate while decreasing the inductance. CONSTITUTION: When first and second contactors 12, 14 are fixed to a base part 18, the major surface thereof are opposed each other through an insulation layer. The first and second contactors 12, 14 touch the emitter terminal 52 and the collector terminal 54 of an element 50 to be measured and feed currents of substantially identical magnitude having the opposite polarities. Consequently, the generated fluxes are offset each other to decrease the inductance thus suppressing noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact structure suitable for supplying a high speed and large current to its terminals for measuring the characteristics of a power device, and more particularly to reducing the inductance of the contact. The present invention relates to a contact body structure that reduces the generation of noise.

[0002]

2. Description of the Related Art An electric measuring apparatus for measuring electric characteristics of a semiconductor element such as a transistor supplies a current and a voltage to each terminal of a semiconductor element which is an element to be measured and measures the voltage and the current at each terminal at that time. Then, the electrical characteristics of the device under test are measured by this. At this time, the contact structure is used to supply voltage and current to each terminal of the device under test.

FIG. 3 is a perspective view of an example of a conventional contactor structure. This contactor is used as an interface with the element to be measured of the above-mentioned electrical characteristic measuring apparatus. Here, as the device under test 50, a three-terminal semiconductor device such as a transistor is shown as an example. The contact structure 30 has first, second and third contacts 32, 34 and 36, which are fixed to a pedestal portion 38.
The tip ends of the first, second and third contactors 32, 34 and 36 are the first, second and third terminals 5 of the device under test 50.
Contact 2, 54 and 56 to supply current and voltage respectively.

More preferably, the pedestal portion 38 has first, second and third detection contacts for detecting the voltage values of the first, second and third terminals 52, 54 and 56 of the device under test 50. Children 42, 44 and 46 are provided. These detection contacts have high input impedance, and the first, second and third contacts 32, 34 and 36 are the first and second contact elements of the device under test 50.
Also, the current supplied to the third terminals 52, 54 and 56 is not changed. In addition, the current value of each terminal is the first, second and third contacts 32, 34 and 36.
It is detected by measuring the voltages generated in the resistors (not shown) provided in the measuring device in series relation with each other. The contactor and the detection contactor are fixed to the screw holes 72 provided in the pedestal portion 38 by a male screw 74 and a female screw 76, respectively.

Each of the contacts 32, 34 and 36 is plate-shaped, and the width thereof is, for example, about 5 mm, and the length from the pedestal portion to the tip end portion in contact with each terminal of the device under test is 90 to, for example.
There is about 100 mm. Due to the length of each contact,
It is possible to elastically contact the terminals of the device under test 50 and to ensure the durability of the contactor. In addition, this is necessary because of the mechanical structure of the existing measuring device, and when the contactor is worn out, the entire contactor structure can be replaced.

The pedestal portion 38 moves up and down, for example, by a mechanical mechanism of the electrical characteristic measuring apparatus, so that the contacts 32, 34 and 36 can repeat contact and non-contact with the terminals of the device under test 50. Often there are. In this case, the measured element 50 is replaced by a mechanism such as a belt conveyor when the pedestal portion 38 moves upward, and the measured element 50 moves when the pedestal portion 38 moves downward and each contact comes into contact with each terminal. 5
A property of 0 is measured. By repeating this operation, the characteristics of the plurality of measured elements are sequentially measured. The pedestal portion 38 is made of a member having a high pressure resistance such as Teflon (registered trademark) resin or acetal resin. Such members are formed by machining.

Conventionally, a contact switch has been used for controlling a motor or the like, but recently, a semiconductor switch has been replaced. These semiconductor switches are GT
These are power devices such as O, thyristors, MOSFETs, and insulated gate bipolar transistors (IGBTs), all of which are capable of handling a large current and a high voltage, although their degree and usage are different. Therefore, it has become necessary to measure the electrical characteristics of such power devices.

Considering an insulated gate bipolar transistor (IGBT) as one of power devices, it has three terminals, that is, an emitter terminal, a collector terminal and a gate terminal, and a collector terminal is provided with a voltage applied to the gate terminal. The current can be controlled. The IGBT is
400 to 800 A (ampere) as its collector current
It is becoming more manageable. Therefore, the current to be supplied to the terminal of the device under test (IGBT) by the contact body structure at the time of measurement also requires a significantly larger value than in the past.

In a circuit that handles dynamic characteristics of a large current such as switching, it is necessary to reduce the inductance as much as possible.
This is because, when the inductance is L, when the current I per time Δt changes by ΔI, an electromotive force E is generated according to the following equation 1 and causes noise. This causes a measurement error in the characteristics of the device under test, and may damage the device under test. In particular, in a circuit that handles dynamic characteristics of large current, ΔI / Δt is large, which causes a problem. Note that Φ in the equation 1 is a magnetic flux generated by the flow of current.

[0010]

## EQU1 ## E = -ΔΦ / Δt = -L (ΔI / Δt)

[0011]

The contactor included in the contactor structure requires a certain length because of the mechanical structural characteristics of the measuring device as described above. However, it has been experimentally found that such a contact produces an inductance of about 10 nH (nano-Henry) per cm length. In particular, from the base portion 38 of each contactor to the measured element 5
Inductance occurs due to the length of contact with the zero terminal. For example, when considering the first and second contactors of the conventional example shown in FIG. 3, the lengths from the pedestal portion 30 to the terminals of the device under test are about 10 cm, respectively, so that the total of two contactors is about 200 nH. Will have inductance. 200 A for 100 ns with this conventional contactor
When a current pulse rising up to is supplied, the electromotive force E at this time is expressed by the following equation 2.

[0012]

[Equation 2] E = 200 × 10 ^-9 × 200 / (100 × 10 ^-9 ) = 400V

As shown in the equation 2, when a current of about 200 A is changed at a high speed for about 100 nsec by switching or the like, a spike voltage of about 400 V may be generated, which causes a measurement error and damage to the device under test. The risk of becoming very large. Fig. 4 shows the conventional contact structure
FIG. 7 is a waveform diagram in which a collector-emitter voltage V _CE is measured when a pulsed collector current Ic is supplied to T (device to be measured). As shown in this figure, when the collector current Ic is supplied by the conventional contact body structure, spike noise is generated in the collector-emitter voltage V _CE at the fall thereof. At the rise of the collector current Ic, the IGBT is saturated, so spike noise does not appear. Even in the conventional contact body structure, there is no problem when the supplied current is direct current or low speed, and the measurement error can be relatively small when measuring the electrical characteristics of the device under test. However, supplying a large current with a rapid change due to switching or a large current with a high frequency to the device under test poses a risk of damage, and also causes a large measurement error when measuring its electrical characteristics. I will end up. That is, the conventional contact body structure cannot supply a current to the device under measurement when measuring the dynamic characteristics.

Therefore, an object of the present invention is to provide a contact structure having reduced inductance. Another object of the present invention is to provide a contact structure suitable for supplying a high speed current to a power device. Still another object of the present invention is to provide a contactor structure that can simplify the manufacturing process.

[0015]

SUMMARY OF THE INVENTION The present invention is directed to a contact assembly, particularly suitable for supplying high speed, high current to power devices. The contactor structure of the present invention includes plate-shaped first and second contactors and a pedestal portion. First plate
The tip of the contactor is in contact with the first terminal of the power device, and the tip of the plate-shaped second contactor is in contact with the second terminal of the power device. These first and second contacts are fixed to the pedestal by a known method such as screws. At this time, in the contactor structure of the present invention, the main surfaces of the plate-shaped first and second contactors are opposed to each other via the insulating layer. The currents supplied to the first and second terminals by the first and second contacts have substantially the same magnitude and opposite polarities. By this, the first
And the magnetic fluxes generated by the current flowing through the second contact cancel each other out, and the inductance decreases.
Therefore, noise generated by the inductance when supplying a large current can be reduced. Further, by coating the portions other than the contact portions at both ends of the first and second contacts with the insulating layer, the assembly process such as fixing the first and second contacts to the pedestal can be simplified.

[0016]

1 is a perspective view of a preferred embodiment of a contactor assembly 10 of the present invention. Preferably, as shown in the conventional example,
A detection contact is also provided on the pedestal portion 18, but it is omitted here for simplicity. In the contactor structure 10 of the present invention, the main surfaces of the plate-shaped first and second contactors 12 and 14 are fixed to the pedestal portion 18 so as to face each other with an insulating layer interposed therebetween. The insulating layer will be described later. The pedestal portion 18 has a plurality of screw holes 7
2 is provided, and the contactor is fixed to the pedestal portion 18 by using the male screw 74 and the female screw 76. Of course, in accordance with this, the contact 70 is also provided with the opening 70. Although FIG. 1 shows an example of an IGBT as the device under test 50, the present invention is generally applicable to any power device. First and second contacts 12 and 1
The tip portions of 4 are brought into contact with the emitter (first) terminal 52 and the collector (second) terminal 54 of the IGBT (device to be measured) 50, respectively. The third contact 16 has a gate (third) terminal 5
Contact 6 Each contact is electrically connected to an electrical measuring device (not shown) at contact points 22, 24 and 26 at its respective ends.

As can be seen from the equation 1, the inductance L is generated when the current changes rapidly because the magnetic flux Φ around the current path (contact in this case) changes. Is. Therefore, if the magnetic flux Φ can be canceled out, the inductance L decreases. Therefore, as shown in FIG. 1, the first and second contacts 12 and 14 are configured such that their main surfaces are opposed to each other with an insulating layer in between, and the magnitudes of the currents supplied by the first and second contacts 12 and 14 are substantially equal to each other and have opposite polarities. If so, the magnetic fluxes Φ generated in the respective current paths (contacts) cancel each other out, and the inductance decreases. Therefore, if the first and second contacts 12 and 14 are respectively brought into contact with the emitter and collector terminals 52 and 54 of the device under test (IBGT) 50 to supply a current,
The magnitudes of the currents supplied to the second contacts 12 and 14 are substantially equal to each other and have opposite polarities, so that the inductance at the time of current supply is reduced.

In FIG. 1, IBGT is used as the device under test 50.
However, the same can be applied to GTOs and thyristors. That is, the first and second contacts 12 and 14 may be brought into contact with the anode and cathode terminals thereof. In this case, it goes without saying that it is necessary to separate the tip portions of the contacts that come into contact with the terminals according to the distance between the terminals of the device under test. Therefore, as shown in FIG. 1, there is a portion where the main surfaces of the tip of the contactor are curved and separated from each other without their main surfaces facing each other, but the effect is small because the area is relatively small as a whole. .

As shown in FIG. 1, first and second contacts 1
The insulating layer provided between the opposing main surfaces of 2 and 14 is the first
Alternatively, the main surfaces of the second contacts 12 and 14 may be formed by coating an insulating film such as Teflon (registered trademark) or epoxy. Further, as shown in FIG. 2, the insulating sheet 80 made of polyimide or the like may be simply sandwiched. In any case, the thinner the insulating layer is, the narrower the space in which the magnetic flux Φ is generated is, and thus the inductance can be reduced.

When the main surfaces of the first and second contacts are opposed to each other with the insulating layer interposed therebetween, not only the electrical characteristics are improved as described above, but also the machining is good.
When producing a small amount, the pedestal portion 18 has a screw hole 72 or the like formed by machining a member that has been generated once with a drill or the like. Therefore, if the main surfaces of the first and second contacts are faced to each other and overlapped and fixed to the pedestal portion 18, the number of screw holes 72 to be formed is reduced. Further, since at least two contacts are fixed to the pedestal together, the assembly process is also simplified. With these, the manufacturing cost can be reduced.

Further, depending on the current value and the current fluctuation speed, in addition to the first and second contact elements 12 and 14 being fixed in an overlapping manner, the third contact element 16 may also be fixed in an overlapping manner. There are cases. This may be performed in a range that does not affect the terminals of the device under test in consideration of the electrical characteristics. In this case, for example, a thin insulating layer is used between the first and second contacts 12 and 14, and in comparison with this, the first and second contacts 12 and 14 and the third contact are used. A relatively thick insulating layer may be provided between the electrodes 16 and 16 so that the electrical characteristics do not affect each other. According to these, even if there are three or more contacts, they are stacked together and fixed to the pedestal, further simplifying the pedestal processing,
In addition, the assembly process is also simplified. With these, the manufacturing cost can be reduced.

A problem when stacking a plurality of contacts is a conductive portion exposed inside the opening 70 provided in each contact. If the male screw 74 is inserted into the opening 70 and the screw hole 72 of the pedestal while the conductive portion inside the opening 70 of the contactor is exposed, the creepage distance of the adjacent contactor due to the male screw 74 becomes short, and the pressure resistance performance deteriorates. To do. So usually,
As shown in FIG. 2, a male screw 74 is passed through a ring-shaped insulator 78 made of plastic or the like, and an opening 70 is formed in the insulator 78.
The contacts 12 and 1 are prevented from exposing the inner conductive portion.
Fix 4 to the base. Further, the first contact 12 and the second
It has been conventionally performed to change the diameter of the opening 70 provided in each of the contacts 14 to increase the creepage distance. Also,
An insulating sheet 80 is used as an insulating layer between the overlapping contacts. In this example, the insulating sheet 80 is made of a transparent polyimide resin. The insulating sheet 80 is preferably wide enough to sufficiently protrude from the end of the main surface of the contactor. As a result, the creepage distance between the ends of the main surfaces of the stacked contacts can be made sufficiently long, and the pressure resistance can be improved.

However, if the contactor is coated with an insulating film such as Teflon as described above, and especially the conductive portion inside the opening 70 is also coated, the creepage distance can be increased without using the ring-shaped insulator 78. You can get enough. FIG. 1 shows an example in which the entire contactor is coated with an insulating film. Even if the whole contactor is coated with an insulating film, the elements to be measured 5 on both ends of the contactor
The tip portion that contacts each terminal of 0 and the contact portion that is the contact portion with the measuring device may be uncoated. The non-coated portions of the contact portions on both ends of these contacts are shown by hatching in FIG. According to this, FIG.
Even if the insulating sheet 80 and the ring-shaped insulator 78 that are wider than the main surface of the plate-shaped contactor shown in FIG.
Withstand voltage higher than that of Fig. 2 can be realized, and
The assembly process is simplified. It is known that the insulating layer formed by coating can be formed with a thickness of about 0.1 mm. In addition, the uncoated parts of different contacts are designed to obtain the required creepage distance.
For example, the contact portion 22 of the first contact 12 and the second contact 14
The distance between the contact point 24 and the contact portion 24 is longer than that in the case of FIG. 2 by extending the first contactor 12.
As you can see.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described herein, and various modifications and changes can be made as necessary without departing from the gist of the present invention. It will be apparent to those skilled in the art that changes can be made. For example, as shown in the related art, it goes without saying that detection contacts for voltage detection at each terminal may be provided in the example shown in FIG.

[0025]

According to the contact structure of the present invention, the main surfaces of the first and second contacts are opposed to each other with the insulating layer interposed therebetween, so that the contact can generate a high-speed large current to the power device. The inductance generated at the time of supply can be reduced, and thus the noise generated by the inductance can be reduced. That is, it is suitable for supplying a current to the device under test when measuring the dynamic characteristics of the device under test. Further, since at least two contacts are overlapped and fixed to the pedestal portion, the labor of forming the screw holes in the pedestal portion is reduced, and the assembly process is also simplified, so that the manufacturing cost can be reduced. If the contactor is entirely coated with an insulating layer excluding the contact parts on both ends, it is not necessary to bite the insulator inside each opening when fixing the contactor to the pedestal part, simplifying the assembly process. And the breakdown voltage can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a preferred embodiment of the contactor structure of the present invention.

FIG. 2 is a perspective view of another preferred embodiment of the contactor structure of the present invention.

FIG. 3 is a perspective view of an example of a conventional contactor structure.

FIG. 4 shows a collector current Ic applied to a device under test using a conventional contactor.
FIG. 7 is a waveform diagram in which a collector-emitter voltage V _CE is measured when a voltage is supplied.

[Explanation of reference numerals] 10 contactor structure 12 first contactor 14 second contactor 16 third contactor 18 pedestal part 22 first contact part 24 second contact part 26 third contact part 30 contactor structure 32 first contact Element 34 Second contact element 36 Third contact element 42 First detection contact element 44 Second detection contact element 46 Third detection contact element 50 Measured element 52 First terminal 54 Second terminal 56 Third terminal 70 Contact opening 72 screw hole 74 male screw 76 female screw 78 ring-shaped insulator 80 insulating sheet

Claims (3)

[Claims] 1. A contactor structure for supplying an electric current to a power device, wherein a tip portion contacts a first terminal of the power device, and a plate-shaped first contactor, and the tip portion comprises the power device. A plate-shaped second contactor that contacts the second terminal of the above, and a pedestal portion that fixes the first and second contactors, and the main surfaces of the first and second contactors through an insulating layer. A contact body structure characterized by being opposed to each other. 2. The contactor structure according to claim 1, wherein the currents supplied to the first and second terminals by the first and second contacts have substantially equal magnitudes and opposite polarities. . 3. The contactor assembly according to claim 1, wherein the first and second contactors are coated with an insulating layer except for contact portions at both ends.