JPH054034B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a test device for semiconductor integrated circuits.

[Conventional technology]

FIG. 3 shows a conventional test device for semiconductor integrated circuits. In the figure, reference numeral 1 applies a test signal to the signal line 2 based on a program, and measures the current flowing into the signal line 2 and the current flowing from the signal line 2. 3 is connected to the signal line 2 at one end; 1, a peripheral circuit having a switch means 4 consisting of a relay that is controlled on and off based on a program; 5, a contact probe connected to the other end of the switch means 4; 6, the test apparatus main body 1 and a signal line 2; A monitor point 7 is provided between a P-type semiconductor substrate 7a and an N ⁺ type semiconductor integrated circuit, and 7 is a semiconductor integrated circuit which is a device to be measured. It has a diffusion layer 7b.

Next, a method for testing a semiconductor integrated circuit using the semiconductor integrated circuit testing apparatus configured as described above will be described. First, when the contact probe 5 is brought into contact with the diffusion layer 7b and the test apparatus main body 1 is operated, the switch means 4 is turned on based on the program of the test apparatus main body 1, and a predetermined voltage is applied to the signal line 2. As a result, a current flows to the diffusion layer 7b and the semiconductor substrate 7a of the semiconductor integrated circuit 7 via the signal line 2, the switch means 4, and the contact probe 5, or a contact is made from the semiconductor substrate 7a and the diffusion layer 7b of the semiconductor integrated circuit 7. A current flows into the test apparatus main body 1 via the probe 5, the switch means 4, and the signal line 2. These currents are measured by the test device main body 1, and the measured values are compared with pre-programmed standard values to determine whether the semiconductor integrated circuit 7 is a good product or a defective product.

Further, when testing a semiconductor integrated circuit (not shown) other than the semiconductor integrated circuit 7, the switch means 4 is turned off based on the program of the test apparatus main body 1 in order to eliminate the influence of the semiconductor integrated circuit 7. A switch means (not shown) connected between a contact probe (not shown) for measuring another semiconductor integrated circuit and the signal line 2 is turned on, and the test is performed in the same manner as above. .

[Problem that the invention seeks to solve]

However, in the semiconductor integrated circuit testing apparatus configured as described above, if a disconnection or short circuit occurs in the switching means 4 or the signal line 2 for some reason, normal measurement conditions cannot be obtained, and the product may not be good. There is a great risk that the semiconductor integrated circuit 7 that should be a good product will be mistakenly judged as a defective product, or that a semiconductor integrated circuit 7 that should be a defective product will be mistakenly judged as a good product, and there is also a risk that a good semiconductor integrated circuit 7 will be made a defective product. It also involved sexuality. In particular, signal line 2
This becomes a very serious problem when a large number of tests are carried out by connecting many switch means and contact probes to the switch.

This invention has been made in view of the above points, and provides a test device for semiconductor integrated circuits that allows checking of the switch means before testing the semiconductor integrated circuit, and allows the test to be always performed under normal measurement conditions. The purpose is to obtain a device.

[Means for solving problems]

The test device for semiconductor integrated circuits according to the present invention includes:
A diode having a polarity for passing a check signal is connected between the other end of the switch means to which a signal line is connected to one end and a check signal line to which a check signal of opposite polarity to the test signal of the switch means is applied.

[Effect]

In this invention, the diode can transmit the check signal to the switching means before testing the semiconductor integrated circuit, and since the check signal passing through the diode has the opposite polarity to the test signal, it has no effect when testing the semiconductor integrated circuit. It acts so as not to affect the

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows the off-check state of the switch means 4 before testing a semiconductor integrated circuit, and FIG. 2 shows the on-check state. In the figure, 8 is a diode whose cathode is connected to the other end of the switch means 4; 9 is a check signal line connected to the anode of this diode and to which a check signal is applied from the test device main body 1 based on the program; 10 is a check signal line 9 provided between the test device main body 1 and the signal line 2; A second monitoring point that monitors the current or voltage appearing at

Next, a method for checking the switch means 4 in the semiconductor integrated circuit testing apparatus constructed as described above will be described. First, when the contact probe 5 is brought into contact with the diffusion layer 7b and the test device main body 1 is operated for a temporary test, the switch means 4 is turned off based on the program of the test device main body 1, and the state shown in FIG. 1 is set. Ru. At this time, the test device main body 1 applies a forward voltage to the diode 8. For example, conditions are set so that 0V is output to the monitor point 6 on the signal line 2 and 1V is output to the second monitor point 10 of the check signal line 9. Then,
If the switch means 4 is normal and in the OFF state, a current flows through the check signal line 9 and the diode 8 to the diffusion layer 7b and the substrate 7a of the semiconductor integrated circuit 7, but this current is opposite to the test signal. Since the diffusion layer 7b and the substrate 7a are connected in opposite polarities, the leakage current is only a small amount. Therefore, no current is detected at the monitor point 6, and a slight leakage current is detected at the second monitor point 10. On the other hand, if the switch means 4 is in an abnormal state caused by being switched off for some reason,
Current flows from the check signal line 9 to the signal line 2 via the diode 8 and the switch means 4 in the shorted state. The value of this current depends on the resistance value from the second monitor point 10 to the monitor point 6, and is larger than the slight leakage current of the switch means 4 when it is normal. Therefore, the current value at the second monitor point 10 is measured. This allows off-checking of the switch means 4.

Next, the switch means 4 is turned on based on the program in the test apparatus main body 1, resulting in the state shown in FIG. Then, if the switch means 4 is normal and turned on, the signal line 2 is connected from the check signal line 9 via the diode 8 and the switch means 4.
A current flows through the second monitor point 10, and a current value that is dependent on the resistance value from the second monitor point 10 to the monitor point 6 appears at the second monitor point 10. On the other hand, switch means 4
is turned off for some reason, and a current flows from the check signal line 9 through the diode 8 to the diffusion layer 7b and substrate 7a of the semiconductor integrated circuit 7, and a minute leakage current flows to the second monitor point 10. The value of will appear. Therefore, the second monitor point 10
By measuring the current value at , the switching means 4 can be turned on.

The test device main body 1 is programmed to stop the next test of the semiconductor integrated circuit 7 when the switch means 4 determines that there is an abnormality in either the above-mentioned off-check or on-check. This prevents the misjudgment of No. 7 and damage. On the other hand, if the switch means 4 is determined to be normal in both off-check and on-check, the semiconductor device main body 1 tests the semiconductor integrated circuit 7 in the same manner as shown in FIG. 3 above. At this time, the diode 8 is connected to the switch means 4.
Since it is connected in the opposite direction to the connection point between the contact probe 5 and the contact probe 5, it does not have any influence on the test of the semiconductor integrated circuit 7. In addition, for further accuracy, the second monitor point 1 may be set so that a voltage in the opposite direction is always applied to the diode 8 during the test of the semiconductor integrated circuit 7.
0 may be applied from the test apparatus main body 1.

〔Effect of the invention〕

As described above, in this invention, a diode is connected between the other end of a switch means having a signal line connected to one end and a check signal line to which a check signal having a polarity opposite to that of the test signal of the switch means is applied. This makes it possible to check the switching means before testing the semiconductor integrated circuit, thereby reducing erroneous judgments of the semiconductor integrated circuit and preventing damage to the semiconductor integrated circuit.

Further, during a check, only a check signal having a polarity opposite to that of the test signal is applied to the semiconductor integrated circuit by the diode, so that the check signal has no effect on the test of the semiconductor integrated circuit.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention. FIG. 1 is a circuit diagram of the main part in an off-check state, FIG. 2 is a circuit diagram of the main part in an on-check state, and FIG. 3 is a conventional circuit diagram for a semiconductor integrated circuit. FIG. 2 is a circuit diagram of the main parts of the test device. In the figure, 2 is a signal line, 4 is a switch means, and 5 is a signal line.
is a contact probe, 7 is a semiconductor integrated circuit, and 8 is a contact probe.
is a diode, and 9 is a check signal line. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A switch means having one end connected to a signal line to which a test signal of a semiconductor integrated circuit is applied; a contact probe connected to the other end of the switch means;
A test for semiconductor integrated circuits comprising a diode of polarity connected between the other end of the switch means and a check signal line to which a check signal for the switch means having a polarity opposite to that of the test signal is applied, and passing the check signal. Device.