KR100363936B1 - Ic testing method and ic testing device using the same - Google Patents

Abstract

In an IC test apparatus for performing a functional test and a DC test, a high resistance resistor is connected to the output side of the DC test apparatus, and the functional test apparatus is connected even when the DC test apparatus is connected to the functional test apparatus by connecting the resistor. This allows the operation to be performed normally, thereby inserting a DC test during the execution of the functional test, executing the function test and the DC test at the same time, and executing the control that takes time such as switching the switch in the DC test device during the function test. The test time is shortened so that the switching time of is not added to the time required for the test.

Description

IC test method and IC test apparatus using the test method {IC TESTING METHOD AND IC TESTING DEVICE USING THE SAME}

Conventionally, in an IC test apparatus for testing a semiconductor device such as a memory, a functional test asking whether the semiconductor device functions normally or not and a direct current test asking whether each terminal of the semiconductor device has a predetermined direct current characteristic or not are performed. Thus, the IC determined to be normal in both tests was judged as good quality.

3 shows a schematic configuration of an IC test apparatus. In the figure, TES denotes a code attached to the entire IC test apparatus. The interior of the IC test apparatus TES is roughly divided into a main controller MAIN, a functional test apparatus 100 and a direct current test apparatus 200.

The main controller MAIN is constituted by a computer system and controls the functional test apparatus 100 and the DC test apparatus 200 through the bus line BUS. The functional test apparatus 100 is constituted by a pattern generator 102, a timing generator 104, and a functional test unit 106A, 106B ... 106N.

The functional test units 106A to 106N are provided corresponding to the respective terminals of the IC under test 300, and the switches S _{11 to} S _1n are turned on and off to control the functional test units 106A to 106N. It becomes a structure which can be controlled in the state isolate | separated from the state connected to each terminal of 300.

That is, in the functional test, the switches S _{11 to} S _1n are turned on, and the functional test units 106A to 106N are connected to the respective terminals of the IC under test 300 and the respective terminals of the IC under test 300 are connected. Give the test pattern signal and execute the function test.

On the other hand, the DC test apparatus 200 is provided with l to several terminals (in the example of FIG. 3, the case where one DC test apparatus 200 is prepared) are prepared for the terminals of the IC under test 300, and the changeover switch ( By controlling S _{21 to} S _2n one by one in turn, the DC test apparatus 200 is sequentially connected to each terminal of the IC under test 300 so as to sequentially test the DC characteristics of this specific terminal. On the other hand, 400 denotes a controller for controlling the switches _{(S 11 ~S 1n, S 21} ~S 2n).

The internal structure of 106A which is one of a functional test unit is shown in FIG. 4, and the outline of a functional test is demonstrated. The functional test unit 106A (other functional test units have the same configuration) is provided in the waveform formatter 11, the driver 12, the voltage comparator 13, the logic comparator 14, and the defective analysis memory 15. Is configured.

The waveform formatter 11 receives the test pattern data from the pattern generator 102 and generates a test pattern signal having an actual waveform. The timing generator 104 gives the waveform formatter 11 a timing signal defining the rising and falling timing of the test pattern signal.

The test pattern signal output from the waveform formatter 11 is shaped into a waveform having an amplitude having a predetermined logic value by the driver 12, and the switch S ₁₁ is passed through a bag to a predetermined terminal of the IC under test 300. The data is supplied and stored in the IC under test 300. Here, when this terminal is an I / 0 terminal (input and output terminal), when a test pattern signal is inputted, each terminal of the IC under test 300 is controlled in an input mode, and is output when the input operation ends. The mode is switched. At the timing of switching to the output mode, the contents stored in the IC under test 300 are read out and input to the logic comparator 14 through the voltage comparator 13. On the other hand, when the voltage comparator 13 reads the data output from the IC under test 300, the output terminal of the driver 12 is set to the high impedance mode.

The voltage comparator 13 compares and determines whether the logic of the signal read out from the IC under test 300 maintains the normal voltage value. That is, it is determined whether or not the L logic and the H logic have, for example, 0.8 volts or less and 2.4 volts or more, and the logic value is input to the logic comparator 14 when it has a normal logic voltage.

In the logic comparator 14, an expectation value is input from the pattern generator 102, and this expectation value is compared with the logic value input from the voltage comparator 13 to detect occurrence of inconsistency. If a match occurs, a defect exists in the memory cell of the input address, and the memory is stored at the address of the defect analysis memory 15. After completion of the test, the number of the defective cells is read out from the defect analysis memory 15 and counted. It is determined whether relief is possible or not.

5 shows an example of the configuration of the DC test apparatus 200. The configuration shown shows the configuration in the case where the DC test apparatus 200 operates in the voltage application current adjustment mode. The non-inverting input terminal of the operational amplifier 16 is supplied with a voltage V _L or V _H having a logic value to be applied from the DA converter 17 to the terminal under test IC 300.

An operational amplifier (16) output terminal and the current output terminal (T _I) connected to a resistor (Rl) for current detection is connected between, and the current output terminal (T _I) and a switch (S _a2 between the sensing point (SEN) of ) for connection to a current output terminal (sensing point through the T _I) and a voltage detecting terminal (T _v) for connecting a protective resistor (R3), and the voltage detecting terminal (T _v) between the switch (S _a2), ( SEN). The sensing point SEN is connected to the terminal of the IC under test 300 via the changeover switch S ₂₁ . The inverting input terminal of the operational amplifier 16 is connected to the voltage detection terminal T _v .

On the other hand, the switch S _b connected in parallel with the current detection resistor R1 represents a range switching switch for switching the current measurement range. By controlling this switch S _b to ON, a resistor R2 which measures a small resistance value, i.e., a large current (current in the output mode of the IC 300 under test) is connected to switch to a large current measurement range.

According to the configuration of the DC test unit 200, the operation on the switch (S _a1, S _a2) and the change-over switch (S ₂₁₎ the ON state DA converter 17 to be tested IC (300) terminal, by controlling the amplifier ( The voltage (V _L or V _H ) is applied to the non-inverting input terminal of 16).

That is, since the operational amplifier 16 operates so that the voltages of the non-inverting input terminal and the inverting input terminal are the same, if the non-inverting input terminal of the operational amplifier 16 is given, for example, V _L , the voltage (voltage detection) of the inverting input terminal is detected. The output voltage is controlled as if the terminal T _v ) is equal to V _L. Therefore, the voltage V _L or V _H is given to the terminal of the IC under test 300.

In the DC test mode, each terminal Pi is set to the input mode shown in FIG. The terminal P ₁ is connected to the terminal P ₁ by determining the current flowing in the current detecting resistor Rl with V _L (voltage giving L logic) or V _H (voltage giving H logic) applied to the terminal Pi. The leakage currents I _Rek1 and I _{Rek2 of the} active devices Q ₁ and Q ₂ may be measured. 18 denotes an phosphate circuit for taking out the voltage generated in the current detecting resistor Rl, and 19 denotes an AD converter that converts the voltage obtained by the phosphorous circuit 18 into an AD value and outputs a digital value.

In the case of measuring the leakage currents I _Rek1 and I _Rek2 described above, the changeover switch S _b is turned off to measure the voltage generated at the current detection resistor R1 of about 100 kΩ having a relatively high resistance value, thereby measuring the IC under test. The leakage currents I _Rek1 and I _Rek2 flowing through the input terminals of 300 are measured. On the other hand, a protective resistor (R3) is a reversal of the relative resistance dietary small (the number of 10Ω or so) and consists of a resistor of the resistance value, during the actual operation switch (S _a1, S _a2) at the same time, even when controlled to an off state the operational amplifier 16 It is a resistor to secure the closed loop for the input terminal and to protect the operational amplifier 16 to prevent the operation of the operational amplifier 16 from reaching a saturation state.

The above will give an overview of the functional test and the DC test in the IC tester. Here, conventionally, the above-described functional test and direct current test are conducted at completely different timings. That is, after one test is performed, the other test is performed. In particular, in the direct current test, it is necessary to control to switch the switching switches S ₂₁ , S ₂₂ ... S _2n , and control to switch the switches S _{11 to} S _1n shown in FIG. 3. The shape is demonstrated using FIG.

A function switch is shown in Figure 3 if the test (S _a1, S _a2) and the change-over switch (S ₂₁ ~S _2n) both change in a state of OFF, the DC test unit 200 is to be tested IC (300) The switch is disconnected from the terminal and the switches (S _{11 to} S _1n ) are all turned on to perform the function test. That is, since the output impedance of the DC test apparatus 200 is relatively low by a few Ω, if the DC test apparatus 200 is electrically connected as a load of the functional test apparatus 100 during the function test, the function test apparatus 100 The waveform of the test pattern signal supplied to the IC under test 300 is deteriorated, so that a normal function test cannot be performed.

For this reason, all of the changeover switches S _{21 to} S _2n and the switches S _{a1 to} S _a2 are controlled to be in an off state, so that the DC test apparatus 200 is not connected to any terminal of the IC 300 under test. The function test is carried out by controlling.

On the other hand, in the case of performing the DC test, first, the switches S _{11 to} S _{1 n} are all controlled to be in the ON state, and the functional test units 106A to 106N are connected to all terminals of the IC 300 under test. In this state, the IC 300 under test is given an initialization pattern for performing a direct current test.

That is, when the terminal to be subjected to the DC test is an I / O terminal, an initialization pattern (see Fig. 7C) for setting the mode of the terminal to the input mode is input from the functional test apparatus 100. With the terminal to be subjected to the DC test set in the input mode, control is performed to separate the functional test units 106A to 106N from the terminals of all the ICs under test 300 from the terminals to be subjected to the DC test.

In this state, the changeover switch (S ₂₁ ) is controlled to the on-state test. The DC test measures the leakage currents I _Rek1 and I _Rek2 (see Fig. 6) flowing through the terminals while the logic values of the H logic and the L logic are applied to the terminals of the IC 300 to be tested, and the leakage current values are determined in advance. If it is less than the predetermined value, it is determined as a quantity.

To give an initialization pattern for each terminal to be tested in this way because of carrying out the direct current test at each terminal switch (S ₁₁ ~S _1n) of the on and off control time (T _sw1), a change-over switch (S ₂₁ ~S _2n ) Needs a time T _pi (see FIG. 7D) to which the time T _sw2 is applied. The time T _sw1 giving the initialization pattern and the time T _{sw2 for} controlling switching between the switching switches S _{21 to} S _2n correspond to the time for switching the relay (a few ms), and the time for measuring the current. Even if (T _IM ) (FIG. 7E) is a short time, the time T _{pi added to} this is a relatively long time. Therefore, if the switching control of the switches S _{11 to} S _1n and the changeover switches S _{21 to} S _2n is performed for every terminal, the time required for the direct current test becomes long. For this reason, when a large amount of ICs are tested, it is a big obstacle.

An object of the present invention is to propose an IC test method which can test a large amount of IC in a short time by shortening the IC test time, and an IC test apparatus using the test method.

The present invention provides an IC test method capable of performing a functional test and a DC test in a short time in a short time when performing a functional test and a direct current test of a semiconductor device such as a memory composed of a semiconductor integrated circuit, and an IC using this method. It relates to a test apparatus.

1 is a block diagram showing one embodiment of an IC test apparatus employing the IC test method according to the present invention;

2 is a timing chart for explaining an IC test method according to the present invention;

3 is a block diagram for explaining an outline of a conventional IC test apparatus;

4 is a block diagram for explaining the configuration of a functional test apparatus used in the IC test apparatus shown in FIG.

FIG. 5 is a connection diagram for explaining the configuration of a DC test apparatus used in the IC test apparatus shown in FIG. 3; FIG.

Fig. 6 is a connection diagram illustrating the shape of the IC terminal under test when the leakage test is performed in the DC test items;

7 shows a timing chart for explaining the shape of a conventional direct current test.

In the present invention, a direct current test device is connected to a terminal of an IC under test through a resistor, and the direct current test device is connected to the terminal of the IC under test, and the direct current test device is studied so that the direct current test device does not become a large load. It is characterized by the fact that the test apparatus can be kept connected to the terminal of the IC under test.

This configuration enables the DC test to be executed by controlling the output terminal of the driver of the functional test device in the high impedance mode even during the functional test, and does not require switch control to disconnect the functional test device during the DC test. An IC test method for performing a leakage test in a DC test item is proposed.

Therefore, according to the IC test method according to the present invention, at the same time as the end of the functional test, the leakage test of the DC test item is completed, and the leakage test may not be executed in a special time. As a result, an advantage of greatly reducing the time required for the test is obtained.

The present invention also proposes an IC test apparatus using the above-described IC test method.

An IC test apparatus according to the present invention is a functional test apparatus for performing a functional test of an IC under test by applying a test pattern signal to each terminal of an IC under test by a driver that can set the state of an output terminal to a high impedance mode;

A direct current test device for measuring a leakage current flowing through each terminal of the IC under test with a predetermined voltage applied to each terminal of the IC under test;

A resistor connected between the sensing point of the DC test apparatus and the terminal of the IC under test,

First control means for outputting a predetermined voltage to the sensing point of the DC test apparatus while the functional test apparatus is executing the functional test;

Second control means for controlling the output terminal of the driver of the functional test apparatus in a high impedance mode when the control operation of the first control means is completed;

Current measuring means for measuring a leakage current flowing through the terminal of the IC under test with the output terminal of the driver controlled in the high impedance mode;

It is composed by.

According to the IC test apparatus according to the present invention, the function test apparatus and the DC test apparatus do not need to be separated from each other during the execution of the functional test even during the execution of the DC test. Therefore, it is possible to carry out a direct current test during the function test without taking the time required for switching the switch.

As a result, even if the direct current test is executed during the execution of the functional test, the functional test and the direct current test are mixed and combined, and the time required for the combined test is not significantly longer than the time required for the original functional test alone. The advantage is that the test and the leak test can be completed in a short time.

BRIEF DESCRIPTION OF DRAWINGS To describe the present invention in more detail, it will be described with reference to the accompanying drawings.

1 shows an embodiment of an IC test apparatus for testing the IC under test in accordance with the IC test method proposed by the present invention. In the drawings, 100 denotes a functional test apparatus, and 200 denotes a DC test apparatus. In the case of performing a functional test, all the switches S _{11 to} S _1n are controlled in an on state, and all functional test units 106A to 106N are connected to respective terminals of the IC 300 under test.

The DC test apparatus 200 controls the switching switches S _{21 to} S _{2 n} one by one in turn, and selectively connects the DC test apparatus 200 to each terminal of the IC under test 300 to connect each terminal. DC test is carried out one by one. On the other hand, in practice, a plurality of DC test apparatus 200 is provided, the number of terminals in charge of the test is made hydrophobic, and the DC test is completed in a short time. However, in this case, the DC test apparatus 200 is connected to one DC test apparatus 200. It is described as executing.

The characteristic of the IC test apparatus according to the present invention is that in the DC test apparatus 200, the resistor R4 is connected in series with the switch S ₂ between the voltage detection terminal T _V and the sensing point SEN. Is in.

That is, in the DC test apparatus 200, the first switch S1 is connected in parallel to the protective resistor R3 connected between the current output terminal T ₁ and the voltage detection terminal T _v . The second switch S2 and the resistor R4 are connected in series between the detection terminal T _v and the sensing point SEN. The third switch S3 is connected between the current output terminal T _I and the sensing point SEN.

When performing the functional test, the first switch S1 and the second switch S2 are turned on and the third switch S3 is set to the off state. In this state, a resistor R4 is connected in series between the sensing point SEN, the current output terminal T _I , and the voltage detection terminal T _v . Therefore, the impedance seen from the functional test unit to which the DC test apparatus 200 is connected can be seen as the resistance of the resistor R4. By selecting the resistance value of the resistor R4 at about 10 kΩ, the impedance of the DC test apparatus 200 in the functional test units 106A to 106N can be regarded as about 10 kΩ.

The signal transmission line connecting each functional test unit 106A to 106N and the IC under test 300 is generally matched with a characteristic impedance of 50?. Therefore, even if a 10 kΩ load (DC test apparatus 200) is connected to each output side of the functional test units 106A to 106N, the impedance of the line does not change significantly, and the IC under test in the functional test units 106A to 106N is used. The waveform of the test pattern signal supplied to the 300 is not disturbed by the connection of the DC test apparatus 200. That is, even during the functional test, even if the DC test apparatus 200 is kept connected to the somewhere of the IC 300 under test, the waveform of the test pattern signal given to the terminal to which the DC test apparatus 200 is connected is not confused and functions normally. You can run the test.

It will be understood from the above description that the DC test apparatus 200 can execute the functional test while being connected to the functional test unit.

The present invention also proposes a method of performing a direct current test (leakage test) while the functional test units 106A to 106N are connected to the respective terminals of the IC 300 under test during the functional test.

That is, a method of measuring the leakage current flowing through the terminal of the IC under test 300 without controlling the switches S _{11 to} S _1n in the OFF state is proposed. As the method, the driver 12 of the functional test unit connected to the terminal at the timing when the DC test apparatus 200 applies a predetermined voltage (voltage giving H logic or L logic) to the terminal to which the leakage current is to be measured. The DC test apparatus 200 measures the leakage current flowing through the terminal of the IC under test 300 while the driver 12 is controlled in the high impedance mode by controlling the output state of the high impedance mode.

For this reason, during execution of the functional test, the main controller MAlN gives the DC test apparatus 200 a command signal for generating a predetermined voltage (H logic or L logic). Specifically, the DA converter 17 is given a digital value for generating a predetermined voltage. The DA converter 17 converts the digital value into DA and outputs the voltage V _L or V _H , and the voltage V _{L is} applied to the non-inverting input terminal of the operational amplifier 16 constituting the DC test apparatus 200. Or V _H ).

The operational amplifier 16 operates so that the voltage of the voltage detection terminal T _v is equal to the voltage given to the non-inverting input terminal. As a result, a voltage equal to the voltage V _L or V _H given in the DA converter 17 is generated at the voltage terminal T _v so that the voltage is sensed through the second switch S2 and the resistor R4. SEN) and is supplied to the terminal of the IC under test 300 through the switch switches S _{21 to} S _2n .

During the execution of the functional test, the switches S _{11 to} S _{1 n} and the switches S ₁ , S ₂ and S ₄ are all turned on, as shown in FIGS. 2B and C. As a method of taking the timing of performing a leakage test of direct current, the following method is given, for example. In the functional test program of the test program input to the main controller MAIN, as shown in Fig. 2A, the timing for the DC test (the time allotted to this timing is set to the time required for testing one terminal) is set in advance. Control signal for controlling all the drivers 12 of each of the functional test units 106A to 106N or the drivers 12 connected to the terminals to be subjected to the DC test in the high impedance mode (see FIG. 2D) at the timing of the DC test. (HlP) is generated, the driver 12 is controlled to a high impedance state, a voltage generation command is given to the DC test apparatus 200, and a predetermined voltage is generated from the DC test apparatus 200 to the applied state. It can be controlled to measure leakage current.

On the other hand, as the timing for interrupting the DC test during the functional test, when the test pattern signal is input to the IC 300 under test, each terminal of the IC under test 300 is set to the input mode at the time of input. As a result, the DC test can be performed as is.

Performing a leak test on one terminal resumes the function test. During the function test, the switching switch (S _{21 to} S _{2 n} ) is switched (see Fig. 2E) to connect the DC test apparatus 200 to the other terminals. After the connection is completed, the timing of the DC test is provided at an arbitrary timing position and the leakage test of the next terminal is performed.

Thus, by completing the switching of the switching switches S _{21 to} S _2n during the execution of the function test, the time required for the leakage test inserted during the execution of the function test can be limited to a very short time. The parallel time is not significantly longer than the time required for the functional test alone.

In the meantime, the current measurement circuit of the DC test apparatus 200 will be briefly described. In this embodiment, a resistor R1 having a high resistance value (about 100 kΩ) for measuring a small current (leakage current) and a resistor having a small resistance value (about 100 Ω) for measuring a large current (output current of the IC under test 300). The case where the range change switch S _b shown in Fig. 5 is omitted by connecting (R2) in series. That is, the diodes Dl or D2 are connected in parallel to the resistor R1 for the microcurrent measurement, and when the large current is measured, the diodes Dl or D2 are turned on and the recurrent current is supplied to the diodes D1 or D2. In this state, the voltage generated in the resistor R2 in this state is detected by the calculation circuit 18B, and this voltage is supplied to the AD converter 19 through the switch S ₅ , and AD converted to, for example, the main controller MAlN. Type in

On the other hand, a voltage of about 10 mV is not generated in the resistor R1 during the microcurrent measurement. For this reason, the diode D1 or D2 is kept in the off state. Therefore, by measuring the voltage generated in the resistor R1, the leakage current flowing through the terminal of the IC 300 under test can be measured. That is, the voltage generated in the resistor (R1) is read out from the phosphoric acid circuit 18, give a read voltage to the AD converter 19 via the switch (S _4), the main control by AD conversion by the AD converter (19) It inputs to instrument MAlN, and determines a good or bad compared with a reference value.

On the other hand, in the large current measurement mode in which the current in the output mode of the IC under test 300 is measured, the switches S _{11 to} S _{1 n} are controlled to be off, and the functional test apparatus 100 is separated from the IC under test 300. Only the DC test apparatus 200 is connected to the IC under test 300. In the DC test apparatus 200, the first switch S1 is turned off and the second and third switches S2 and S3 are turned off. The DC test is performed with the switch S4 turned off and the switch S5 turned on.

As described above, according to the IC test method according to the present invention, switching of the switches S _{21 to} S _2n , which takes a slow response and takes time to complete the operation, is performed during the function test, and the driver 12 is turned on during the function test. Since the test method is controlled to the impedance mode and the DC test (leakage test) is performed, the function is required at the time required for the functional test when the actual time required for the DC test (not including the time required for switching the switch) is added. The test and the leak test can be terminated. As a result, the advantage that the total test time can be shortened significantly is obtained. As a result, the effect is exerted when, for example, a large amount of IC should be tested in a short time in an IC manufacturing manufacturer.

Claims (4)

A functional test device which performs a functional test of the IC under test by applying a test pattern signal to each terminal of the IC under test by a driver that can set the state of the output terminal to the high impedance mode; In the method of testing an IC with an IC test apparatus comprising a direct current test device for measuring a current flowing through each terminal of the IC under test with a predetermined voltage applied to each terminal of the IC under test, While the functional test apparatus is executing a functional test of the IC under test, connecting the sensing point of the DC test apparatus to a terminal of the IC under test through a resistor, and outputting the output voltage of the DC test apparatus to a predetermined voltage. Setting, controlling the driver of the functional test device in the high impedance mode, and leaking current flowing through the DC test apparatus to the terminal of the IC under test with the output terminal of the driver controlled in the high impedance mode. IC test method comprising the step of measuring. A. A functional test device that applies a test pattern signal to each terminal of the IC under test by a driver that can set the state of the output terminal to the high impedance mode, and performs a functional test of the IC under test; B. DC test apparatus for measuring the leakage current flowing through each terminal of the IC under test with a predetermined voltage applied to each terminal of the IC under test; C. The resistance connected between the sensing point of this DC test apparatus and the terminal of the IC under test, D. first control means for outputting a predetermined voltage to a sensing point of the DC test apparatus while the functional test apparatus is executing a functional test; E. second control means for controlling the output terminal of the driver of the functional test apparatus to a high impedance state when the control operation of the first control means is completed; F. current measuring means for performing an operation of measuring a leakage current flowing through a terminal of the IC under test in the DC test apparatus with the output terminal of the driver controlled in a high impedance mode; IC test apparatus, characterized in that configured by. 3. The DC test apparatus according to claim 2, wherein the DC test apparatus is provided with a predetermined voltage to the non-inverting input terminal, outputs a predetermined voltage to the output terminal, and outputs the output voltage to the sensing point through the current detecting resistor. An operational amplifier for returning the voltage of the circuit to the inverting input terminal, and current measuring means for measuring the voltage generated in the current detecting resistor and measuring the leakage current flowing through the terminal of the IC under test. IC test apparatus, characterized in that connected to the terminal of the IC under test. 3. The DC test apparatus according to claim 2, wherein the DC test apparatus includes an operational amplifier having a non-inverting input terminal and an inverting input terminal, and a current detecting resistor having one end connected to an output terminal of the operational amplifier and the other end connected to a current output terminal. A protective resistor connected between the first switch for providing a voltage output from the current output terminal to the voltage detection terminal and the current output terminal and the voltage detection terminal, and the voltage of the voltage detection terminal to the inverting input terminal of the operational amplifier. A feedback circuit for feeding back, a series circuit composed of a second switch and a resistor for supplying the voltage of the voltage detection terminal to a terminal of the IC under test through a sensing point, and the first circuit connected between the current output terminal and the sensing point. 3 is constituted by current measuring means for measuring the current generated in the switch and the current detecting resistor and measuring the current flowing through the terminal of the IC under test; In the mode of measuring the leakage current flowing through the terminal of the IC under test during the functional test, the first switch and the second switch are set to the on state, and the impedance of the DC test apparatus in the functional test apparatus is determined by the resistor. In the DC test mode during the non-functional test, the first switch is turned off, and the second switch and the third switch are turned on to control the current output terminal of the sensing point and the IC under test. IC test apparatus, characterized in that the configuration is connected directly to the terminal.