JPS5819494Y2 - Semiconductor element characteristic selection equipment - Google Patents

Description

[Detailed description of the invention] The present invention is a characteristic selection device that determines and selects the quality of static characteristics of semiconductor devices to be measured such as diodes, and is particularly suitable for checking or rejecting devices with defective characteristics in each process of an automated line. The characteristics of a semiconductor device suitable for this purpose relate to a checking device.

Conventionally, when measuring the characteristics of a semiconductor element that moves continuously or intermittently in a mechanical device, accurate measurement results cannot be obtained due to poor contact between the leads and the measurement terminals, so the leads are held between the measurement terminals to stabilize the contact state. However, erroneous judgments may occur due to the complexity of the drive mechanism of the measurement terminal or wear and failure of the mechanical parts, and the index may be incorrect because the drive mechanism of the measurement terminal is a mechanical structure that involves rotation. There were drawbacks such as slow processing and poor sorting efficiency.

The present invention solves the drawbacks of the conventional device described above, and is an improved device that can determine the quality of the device characteristics in a moving state during transportation, where it is difficult to stop the device and hold it between the measurement terminals. The present invention provides a characteristic checking device for semiconductor elements.

In the characteristic checking device according to the present invention, first, when the measurement terminal and the lead of the semiconductor device to be measured come into contact, a current is supplied to the device from the constant current power supply.

When the power is applied, the electric signal of the element characteristics will change while the power is applied.
It is constantly compared with the reference signal by the voltage comparator, and if the electric signal of the element is higher than the reference signal, the voltage comparator outputs 1, and if it is lower, no output is output. Therefore, the output of the voltage comparator is 0, 1
is repeated.

Comparison and discrimination based on this reference value are simultaneously classified and measured by multiple voltage comparators, but the results are observed for each characteristic classification by a characteristic discriminator many times using a large number of pulse signals while power is being applied, and these observation results are is counted for each characteristic classification.

Next, this count number for each classification is compared with the respective set count number, and the characteristic classification that reaches the set count number first is classified and checked as the determination result of the device under test.

Particularly when checking the characteristics of an element on a belt conveyor or a chute of a mechanical device, where the element under test slides elastically against the measuring terminal, the contact between the element and the measuring terminal tends to be incomplete. In conventional devices that use single pulses or simply repeated pulses to compare and discriminate with a reference value, erroneous judgments are unavoidable.

However, in the characteristic checking device according to the present invention, even when the contact state between the device under test and the measurement terminal fluctuates, it is possible to perform accurate measurement by outputting the most frequently obtained result through a large number of repeated measurements as described above. This device is designed to provide accurate measurement results, and since measurements can be made by simply bringing the device under test into elastic contact with the measurement terminal, it can be freely incorporated into a highly mobile production line, and its uses are extremely wide. .

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the characteristic selection device according to the present invention.
This is a block diagram of the main configuration of a diode Vz checker device. In the figure, 1 is a constant current power supply that supplies a constant current to a diode 3 connected to a measurement terminal 2.

The measurement terminal 2 is attached to mechanical equipment and includes three terminals 2a, 2b, and 2C made of phosphor bronze plates that make elastic contact with the lead wires of the diode 3 to be measured, and a terminal that contacts both leads of the diode 3. 2a and 2b connect the Vz measurement terminal 4, and the terminal 2b and the remaining terminal 2C connect the diode 3.
A sample detector terminal 5 is formed in contact with one side of the lead.

This sample detector terminal 5 is connected to a measurement timing control circuit (not shown), and when the diode 3 is connected to this terminal 5, the power supply circuit is switched and a constant current is supplied to the diode 3.

Vz measurement terminal 4 is connected to voltage comparator 6.

This voltage comparator 6 is composed of three operational amplifiers.
a, 6b, and 6C, and a reference voltage generator 7 is connected to each comparator correspondingly.

The output side of the voltage comparator 6 is connected to a discrimination logic circuit 8,
Although not shown, the output of the voltage comparator 6 (U,
L, S) are input to the characteristic discriminator 8, each measured value is compared and discriminated, and each standard classification (H.

M, L, S).

The output side of this characteristic discriminator 8 is connected to a counter 9, and counts for each characteristic classification, and at the same time, each of these counters 9 is connected to a count number comparator 10, which counts these counts. Input to number comparator 10.

A count number setter 11 is connected to each of the count number comparators 10 for each characteristic classification, and the count number input from the counter 9 and the count number set by the count number setter 11 are compared and determined. , the characteristic items that have reached the set value are taken as the judgment results of the diode under test 3,
It is applied to the output circuit 12.

Next, the operation of the above configuration will be described in more detail. When the diode 3 moving in the mechanical equipment comes into elastic contact with the measurement terminal 2 of the Vz checker device and is electrically connected, the sample detector terminal 5 is short-circuited.

The circuit of the constant current power supply 1 is switched by this signal, and a one-shot pulse of current of, for example, 170 m5 is applied to the diode 3.

An electrical signal generated across the diode 3 by this pulse current is detected by a voltage comparator 6 through a Vz measurement terminal 4.

This voltage comparator can be freely increased or decreased depending on the number of characteristic classification items to be checked. ), for comparison with the 5hort standard (
One input of each operational amplifier receives the Vz voltage of diode 3, and the other input receives Upper standard (IJ) and Lower standard (L ) and 5hort standard (S) (for example, short 1■ or less and set it as IV)
DPM of each reference voltage generator 7a, 7b, 7C
The reference voltage set with (digital panel meter) is input.

The voltage set to this DPM can be arbitrarily set according to the Vz value of the diode to be measured.

The comparison results U, L, and S between the Vz value of the diode 3 and the reference voltage, which are input to the voltage comparator 6, are determined as follows by the characteristic discriminator 8, which is composed of a logic circuit consisting of a combination of an AND circuit, an OR circuit, etc. It is classified into four categories and output.

1. If the Vz value of High (H) diode 3 is larger than the Upp setting value 2. If the VZ value of Middle (M) diode 3 (7) falls between the Upp setting value and the Low setting value 3. Low ( L) When the VZ value of diode 3 is between the Low setting value and the 5hort specified value, 4, 5hort (S) When the VZ value of diode 3 (7) is smaller than the 5hort setting value, it occurs at both ends of the device under test 3 The electrical signals are constantly input to the voltage comparators 6a, 6b, and 6C while power is being supplied to the elements, and the reference signals U, L, and S from the reference voltage generator 7
compared to

This voltage comparator 6 receives an electrical signal from the element as a reference signal U,
It is set to be 1 if it is larger than L or S, and not to be output if it is smaller than 0, but the electrical signal from the element changes if the contact between measurement terminal 2 and diode 3 is poor, so the voltage The outputs H, L, and S from the comparator 6 each repeat 0.1 and change over time.

Next, the outputs H, L, and S from these voltage comparators 6 are inputted to the characteristic discriminator 8, respectively, and are classified into predetermined characteristic classifications H, L, and S.
Classified into M, L, and S.

Although the output from the voltage comparator 6 is not shown, it is strobed with a repetitive pulse emitted from a measurement timing control circuit, for example, a pulse with a 5 ms period, and the output is inputted into the counter 9 every 5 ms.

Counter 9 is High, Middle, Low, 5
hort (7) 4 digits 9 a , 9 b , 9 C,
9d are provided, and each counter is incremented by 1 based on the result every 5ms.

Itoyoshi of these counters 9 is the count number comparator 1, respectively.
0 (10a, 10b, 10C.

10d) and compared with the digital setting values of the corresponding count number setting devices 11 (11a, 11b, 11C, 11d), and the count number of the counter 9 reaches these set count numbers. 9 is input to the output circuit 12 as the determination result of the diode 3 under test.

In this case, the counter 9 uses a counter IC and is operated by the input from the characteristic discriminator 8 while the diode 3 is energized.

The count setting device 11 uses a digital switch that converts a decimal number into a BCD code, and this set value can be arbitrarily set depending on the contact state between the measurement terminal 2 and the diode 3.

In addition, the count number comparator 10 employs an EX-OR circuit,
This output 12 is connected to a judgment indicator and a control circuit of the mechanical equipment.

In other words, if the judgment result is Middle and the product is judged as good, then Middle
By simply turning on the lamp e, the control signal for the mechanical device is not issued, and the entire circuit is reset by turning the timing detection signal ON-OFF to wait until the next detection of the diode 3 to be measured.

If the determination result is High, Low, or 5hort, the counter for counting the number of lighting and occurrences of each lamp is incremented by 1, and the relay driver output transistor is operated to drive the relay.

This relay is connected to the machinery control circuit and can shut down the machinery or automatically reject defective products.

These output circuits 12 are easily constructed using flip-flops.

In addition, in this device, in order to measure the Vz characteristics, the output voltage across the constant current power supply and the diode was used as the characteristic signal, but the I
When measuring r-characteristics, this device can be similarly utilized by converting the output from both ends of a resistor connected in series with a constant voltage power supply and a diode into an electrical signal.

As explained in detail above, the semiconductor device characteristic checker according to the present invention emits a large number of pulses during the conduction period when the power is applied to the semiconductor element to compare it with the standard value of the selected characteristic standard. This method compares the reference count number set according to the state of contact between the element lead and the measurement terminal with the above-mentioned discrimination result, and provides accurate judgment results even when the contact with the measurement terminal is incomplete. It can be installed on a conveyor or chino that moves by elastic sliding, and can be installed in the middle of conveyance, so that a characteristic checker device that is extremely convenient in practice is obtained, and its effects are great.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the characteristic selection device according to the present invention, and is a block diagram of the main configuration of a diode Vz checker device. 1... Power supply (constant current power supply, constant voltage power supply), 2.
...Measurement terminal, 6...Voltage comparator, 8.
... Characteristic discriminator, 9 ... Counter, 10
・・・・・・Count comparator.

Claims (1)

[Scope of utility model registration request] A measurement terminal to which the semiconductor element under test is connected, a power supply connected to this terminal, a voltage comparator that compares the detection signal of the measurement terminal with a reference signal, and a characteristic determination that classifies the compared output signal into a predetermined characteristic classification. a counter that counts the characteristic-classified output for each characteristic classification; a count number comparator that compares the count number for each characteristic classification with a preset count number; The device is configured to include means for emitting a large number of pulses during characteristic measurement, and causes a counter to count the results for each characteristic classification, and compares the results with a count set for each classification to determine the characteristics of the semiconductor element. A semiconductor device characteristic selection device characterized by: