JPH03210716A - Electric switch - Google Patents

Abstract

PURPOSE:To prevent occurrence of noise following on/off of a mechanical contact by connecting a mechanical relay in series with a contactless relay, and putting the mechanical relay on/off with the contactless relay off constantly. CONSTITUTION:When an instruction signal for lighting a lighting apparatus 5 is inputted from a CPU to a control part 4, the control part 4 puts a mechanical relay 3 on first. Then, after a delay of a predetermined time, a contactless relay (SSR) 2 is put on to light the apparatus 5. When an instruction signal for lighting off the apparatus 5 is inputted from the CPU to the control part 4, the control part 4 puts the SSR 2 off first. Then, after a delay of a predetermined time, the relay 3 is put off, so the apparatus 5 is lighted off. The relay 3 is put on/off with the SSR 2 off constantly, so a mechanical contact is opened and closed under discontinuity, thereby occurrence of noise by on/off of the mechanical contact can be prevented.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to electrical switchgear.

(Prior Art) Conventionally, electrical switching devices for electrically turning on and off various devices include mechanical relays that turn on and off power by electromagnetically driving contacts, or semiconductor devices such as SSRs. Non-contact relays that turn power on and off using elements are widely used.

By the way, in general, in the manufacturing process of semiconductor devices, there is a step of measuring the electrical characteristics of a large number of semiconductor devices formed on a semiconductor wafer and inspecting whether or not the devices are non-defective. Probers and testers have traditionally been used in such inspection processes. That is, the prober is
X-Y-Z direction i: A semiconductor wafer is held on a movable wafer mounting table, and the wafer mounting table is driven to place the probe of the probe card on the electrode pad of the semiconductor chip formed on the semiconductor wafer. Touch the needles one after another.

Then, the tester supplies a predetermined measurement signal to the semiconductor chip through the probe needle and measures the output from the semiconductor chip, thereby measuring the electrical characteristics of each semiconductor device formed in large numbers on the semiconductor wafer. and conduct an inspection.

Conventionally, mechanical relays or non-contact relays have been used to electrically turn on and off each electrical device of such an inspection device.

(Problem to be Solved by the Invention) However, in recent years, for example, in the inspection process of semiconductor devices as described above, there are cases where it is required to measure a minute current, for example, a minute current on the order of picoampere-femtoampere. A problem like this is occurring.

In other words, if a mechanical relay is used to turn on and off the electrical equipment of a prober, such as the lighting device of a prober, noise will be generated as the mechanical contacts turn on and off, making it difficult to measure minute currents. or cause malfunction of other control systems.

On the other hand, if a non-contact relay such as an SSR is used, is it possible to prevent the generation of noise when the power is turned on and off using a zero-crossing function, etc.?Since it uses a semiconductor element, there is a slight leakage current when the power is turned off. This leakage current causes noise when measuring minute currents, and there is a problem in that highly accurate measurements cannot be performed. The problem of leakage current when using such a non-contact relay is particularly large when electrically turning on and off the illumination device of the prober (located directly above the measurement position of the semiconductor wafer). It becomes a problem.

The present invention has been made in response to such conventional circumstances, and is an electrical switchgear that can reduce noise generation compared to the prior art and can cope with the measurement of minute currents in semiconductor inspection processes, etc. This is what we are trying to provide.

[Structure of the Invention] (Means for Solving the Problems) That is, the electrical switchgear of the present invention includes a non-contact relay that turns on and off a power source using a semiconductor element, and an electromagnetic switch connected in series to the non-contact relay. A mechanical relay that turns on and off the power by automatically driving a contact; when the power is turned on, the mechanical relay is first turned on, and then the non-contact relay is turned on; and a control means for turning off the mechanical relay after turning off the mechanical relay.

(Function) The electrical switchgear of the present invention includes a non-contact relay, such as an SSR, that turns on and off the power using a semiconductor element, and a non-contact relay that is connected in series to the non-contact relay and electromagnetically drives the contacts to power the It is equipped with a mechanical relay that turns on and off. Then, when the power is turned on, the control means first turns on the mechanical relay and then turns on the non-contact relay, and when the power is turned off, first turns off the non-contact relay and then turns off the mechanical relay.

Therefore, since the mechanical relay is always turned on and off while the non-contact relay is turned off, it is possible to prevent noise from occurring due to the turning on and off of the mechanical contact. In addition, when the power is turned off, the electrical circuit is physically interrupted by the mechanical contacts of the mechanical relay as well as the non-contact relay, so it is possible to prevent the occurrence of minute leakage currents. Generation of noise can be prevented.

(Example) Hereinafter, an example in which the electrical switching device of the present invention is used for electrical control of a lighting device of a prober will be described with reference to the drawings.

As shown in FIG. 1, the electrical switchgear 1 includes a non-contact relay, such as 5SR2, that turns on and off the power using a semiconductor element, and a machine that electromagnetically drives the contacts to turn on and off the power. A control unit 4 for controlling the SSR 2 and the mechanical relay 3 is provided.

The electrical switchgear 1 is inserted between a lighting device 5 of a prober and an AC power source. This illumination device 5 holds a semiconductor wafer 6 and drives it in the x-y-2 direction, and brings probe needles 8 of a probe card 7 into contact with electrode pads of semiconductor chips formed on the semiconductor wafer 6.
It is provided above the mounting table 9 and is used when visually observing the semiconductor wafer 6 and the probe needle 8 for alignment.

As shown in FIG. 2, the mechanical relay 3 of the electrical switchgear 1 receives single-phase AC power supplied to the lighting device 5.
With two contacts, both sides (both hot side and cold side)
It is configured to open and close and turn the power on and off. Furthermore, the 5SR2 is configured to turn on and off the power on the hot side of the mechanical relay 3. Further, the control unit 4 controls the on/off of the mechanical relay 3 and the SSR 2 as shown in FIG. 3 in response to a lighting/extinguishing command signal from a CPU (not shown), and controls the lighting/extinguishing of the lighting device 5. I do.

That is, at time t1, when a command signal to turn on the lighting device 5 is input from the cPU to the control unit 4, the control unit 4 first turns on the mechanical relay 3. Then, after a predetermined time delay Δt, the SSR2 is turned on and the lighting device 5 is turned on.

On the other hand, at time t2, when a command signal to turn off the lighting device 5 is input from the cPU to the control unit 4, the control unit 4 first turns off the 5SR2.

Then, after a predetermined time delay Δt, the mechanical relay 3 is turned off and the lighting device 5 is turned off.

Therefore, the mechanical relay 3 is always turned on and off with SSR2 turned off, and the mechanical contacts are opened and closed in a de-energized state, so noise is generated due to the turning on and off of the mechanical contacts. can be prevented.

In addition, when the power is turned off (when the lighting device 5 is turned off), the 5SR2
At the same time, since the electrical circuit is physically interrupted by the mechanical contacts of the mechanical relay 3, it is possible to prevent the generation of a minute leakage current, and it is possible to prevent the generation of noise caused by the leakage current. . Therefore, the probe needles 8 of the probe card 7 are brought into contact with the electrode pads of the semiconductor chips formed on the semiconductor wafer 6, and the minute current flowing through the semiconductor chips is measured by a tester (not shown) through the probe needles 8 to determine the electrical characteristics. Even when performing an inspection, the inspection can be performed with high accuracy.

In the above embodiment, an example was explained in which the present invention was used to electrically control the illumination device 5 of a prober, but the present invention is not limited to such an embodiment, and the present invention is not limited to such an embodiment, and the present invention is not limited to such an embodiment, and the present invention is not limited to such an embodiment. It may also be used for control. In addition, it is applicable not only to probers but also to any device that has problems such as noise caused by turning on and off mechanical contacts, noise caused by leakage current of non-contact relays using semiconductor elements, etc. can do.

[Effects of the Invention] As explained above, according to the electrical switchgear of the present invention, noise generation can be reduced compared to the conventional one, and it can be used to measure minute currents in semiconductor inspection processes, etc. can.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an electrical switching device according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of the circuit configuration of the electrical switching device shown in FIG. 1, and FIG. FIG. 3 is a diagram for explaining the operation of the electrical switchgear shown in FIG. 1... Electric switchgear, 2... Non-contact relay (SSR), 3... Mechanical relay 4
...control unit, 5 ...prober illumination device, 6 ... semiconductor wafer, 7 ...probe card, 8 ...probe needle , 9...
...Wafer mounting table.

Claims (1)

[Claims] (1) A non-contact relay that turns the power on and off using a semiconductor element; A mechanical relay that is connected in series to this non-contact relay and electromagnetically drives the contacts to turn the power on and off; and a mechanical relay that turns the power on and off by electromagnetically driving the contacts. In some cases, the control means is provided that first turns on the mechanical relay and then turns on the non-contact relay, and when the power is turned off, first turns off the non-contact relay and then turns off the mechanical relay. Characteristic electrical switchgear.