JPH1010200A - Tester and test method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To test an IC having an interfacing for simultaneous input and output and an IC having an interface for other CCT or GTL using a same tester. SOLUTION: At the time of testing an IC having an interfacing for simultaneous input and output, the comparison voltage of an analog comparator 20 is switched depending on the output voltage from a driver 5 using a driver 5 for switching more than two kinds of set voltage, and a comparator 12 for switching the comparison voltage of the analog comparator 20 by the output voltage from a driver 5. When an element is tested by switching the input/ output, output voltage from the driver 5 is matched with the terminal voltage of the element to be tested other than high and low voltages at the time of output from the element to be tested.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor test apparatus, and more particularly to a semiconductor test apparatus suitable for testing a device having an interface such as CTT, GTL, and full duplex.

[0002]

2. Description of the Related Art An interface of a semiconductor device employs a method of dividing a signal pin according to the type of input and output, or a method of performing input and output with the same pin in a time sharing manner in order to distinguish between an input signal and an output signal. I have. The former has a problem that the number of signal pins increases, and the latter has a problem that it takes time to exchange signals.

[0003] To solve these problems, ISCC95
/ SESSION2 / DATA COMMUNICAT
There is a semiconductor device having an interface for performing input and output simultaneously with the same pin as shown in IONS / PAPER WP2.4.

[0004]

The conventional method has the following problems.

That is, ISCC95 / SESSION
2 / DATA COMMUNICATIONS / PAP
When testing a semiconductor device having an interface that simultaneously performs input and output with the same pin as shown in ER WP2.4, a conventional test device for testing an IC having an interface such as CCT or GTL cannot be applied.

That is, in the conventional test apparatus, when an input signal and an output signal are simultaneously handled by the same pin, a test waveform and its response waveform cannot be distinguished, and an expected test cannot be performed.

A first object of the present invention is to provide a method of testing a semiconductor device in which an input signal and an output signal are simultaneously handled by the same pin, and a semiconductor test apparatus therefor.

Further, actually, not only a semiconductor device having an interface for simultaneously performing input and output with the same pin is tested, but also an IC having an interface such as conventional CCT or GTL may be tested.

In such a case, a driver of the test apparatus,
The comparators can be replaced as needed, but the test cost and test time both increase.

A second object of the present invention is to provide a semiconductor capable of testing an IC having an interface for simultaneously performing input and output and another IC having an interface such as CCT or GTL using the same test apparatus. An object of the present invention is to provide an apparatus test method and a semiconductor test apparatus therefor.

[0011]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an input
A semiconductor test apparatus for testing a response waveform by applying a test waveform to a semiconductor device that simultaneously performs output at the same pin, and comparing a composite waveform of the test waveform and the response waveform with a predetermined comparison voltage. The first object is achieved by providing means for setting the predetermined comparison voltage according to the test waveform, and means for comparing the comparison result with a predetermined expected value.

Alternatively, a test method for a semiconductor device in which a test waveform is given to a semiconductor device that performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a composite waveform of the test waveform and the response waveform is obtained. The first object is achieved by comparing with a comparison voltage set according to the test waveform, and comparing the comparison result with a predetermined expected value.

When a test waveform is given to a semiconductor device that performs input / output simultaneously on the same pin, the test waveform and the response waveform from the semiconductor device exist on the same line.

In general, a response waveform from a semiconductor device is input to a comparator of a semiconductor test device, and is compared with a predetermined comparison voltage value to determine whether the semiconductor device is operating normally. Is input, since the test waveform is combined with the response waveform to be compared, it is not possible to correctly judge whether the semiconductor device is operating normally only by comparing with a constant comparison voltage.

According to the present invention, the comparison voltage of the comparator is set to a voltage value corresponding to a predetermined pattern of the test waveform at substantially the same timing as the test waveform, so that the comparison waveform is extracted from the composite waveform.・ I can judge,
A semiconductor device in which input / output is simultaneously performed on the same pin can be tested.

The present invention will be described in further detail. The present invention is directed to a semiconductor test apparatus for applying a test waveform to a semiconductor device which performs input / output simultaneously on the same pin and testing a response waveform thereof. A timing generator for generating a timing signal; a pattern generator for generating a predetermined test pattern; a driver waveform controller for outputting a predetermined control signal from the timing signal and the test pattern; A driver for switching the first and second set voltages to output the test waveform, and a first and second comparison voltage for switching a composite waveform of the test waveform and a response waveform from the semiconductor device according to the control signal; And a digital comparator for comparing the output of the analog comparator with expected values created by the pattern generator and the timing generator. And a comparator.

Alternatively, a test method of a semiconductor device in which a test waveform is applied to a semiconductor device that performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a predetermined timing signal and a predetermined test pattern are used for a predetermined test signal. A control signal is generated, the test waveform is output by switching the first and second set voltages according to the control signal, and a composite waveform of the test waveform and a response waveform from the semiconductor device is converted into the control signal. The output is compared with first and second comparison voltages which are switched according to the output, and the output is compared with a predetermined expected value.

As described above, the setting of the comparison voltage can be realized by switching between the first and second comparison voltages that have already been determined. Similarly, the setting voltage of the driver (generation of the test waveform) can also be obtained.
This can be realized by switching the first and second set voltages that have already been determined. If the switching is realized by the timing signal generated by the timing generator and the control signal generated from the test pattern generated by the pattern generator, the accuracy of extracting the response waveform can be increased and the detection error can be reduced.

Here, the predetermined expected value is a normal output when a test waveform is input to the semiconductor device, and is generated by a timing generator and a pattern generator.

Further, according to another aspect of the present invention, the input
A semiconductor tester for testing a response waveform by applying a test waveform to a semiconductor device that simultaneously performs output with the same pin, and a timing generator for generating a predetermined timing signal and a pattern for generating a predetermined test pattern A generator, a driver waveform controller that outputs a predetermined control signal from the timing signal and the test pattern, and a driver that outputs a test waveform by switching first and second set voltages according to the control signal. A first analog comparator for comparing a composite waveform of the test waveform and the response waveform from the semiconductor device with a first comparison voltage; and a second comparison voltage of a composite waveform of the test waveform and the response waveform from the semiconductor device. And a second analog comparator for comparing the output of the first analog comparator or the second analog comparator according to the control signal. Is selected, and the selected output value is compared with a predetermined expected value.

Alternatively, a test method for a semiconductor device, in which a test waveform is given to a semiconductor device which performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a predetermined timing signal and a predetermined test pattern A control signal is generated, the test waveform is output by switching between the first and second set voltages according to the control signal, and a composite waveform of the test waveform and a response waveform from the semiconductor device is converted to a first comparison voltage. And each of the second comparison voltages, and selects either the comparison result with the first comparison voltage or the comparison result with the second comparison voltage according to the control signal, and the selected The output value is compared with a predetermined expected value.

These characteristics are as follows. The composite waveform is compared with each of the first comparison voltage and the second comparison voltage, and the comparison result with the first comparison voltage or the second comparison voltage is obtained in accordance with the control signal. One of the results of comparison with the comparison voltage is selected.

Even in such an embodiment, since the response waveform can be extracted from the composite waveform, it is possible to test a semiconductor device in which input and output are simultaneously performed on the same pin.

Still another aspect of the present invention is to provide a semiconductor device which performs input / output simultaneously on the same pin by applying a test waveform to the semiconductor device.
A semiconductor test apparatus for testing the response waveform, comprising: a timing generator for generating a predetermined timing signal; a pattern generator for generating a predetermined test pattern; and a predetermined control signal from the timing signal and the test pattern. A driver waveform controller for outputting, a driver for switching the first and second set voltages in accordance with the control signal to output a test waveform, and a driver for outputting a composite waveform of the test waveform and a response waveform from the semiconductor device to the first. A first analog comparator that compares the test waveform with the response waveform from the semiconductor device, a second analog comparator that compares a composite waveform of the test waveform with the second comparison voltage, A first digital comparator for comparing an output value with a predetermined expected value, and comparing an output value of the second analog comparator with a predetermined expected value It is obtained by a second digital comparator that.

Alternatively, a test method of a semiconductor device in which a test waveform is given to a semiconductor device that performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a predetermined timing signal and a predetermined test pattern are used for a predetermined test signal. A control signal is generated, the test waveform is output by switching between the first and second set voltages according to the control signal, and a composite waveform of the test waveform and a response waveform from the semiconductor device is converted to a first comparison voltage. And a second comparison voltage, and a comparison result with the first comparison voltage and a comparison result with the second comparison voltage are respectively compared with predetermined expected values.

These characteristics are as follows. A composite waveform of the test waveform and the response waveform is compared with each of the first comparison voltage and the second comparison voltage, and the comparison result with the first comparison voltage and the second comparison voltage are compared. The comparison result with the comparison voltage is compared with an expected value created in advance.

Even in such an embodiment, since the response waveform can be extracted from the composite waveform, it is possible to test a semiconductor device in which input / output is simultaneously performed on the same pin.

Next, the present invention relates to a semiconductor test apparatus for applying a test waveform to a semiconductor device and testing its response waveform, wherein the first, second, and third set voltages are switched to set the test waveform or the test waveform. A driver for outputting a predetermined termination voltage, and a first and a second switch that switch a composite waveform of the test waveform and the response waveform according to the test waveform when the semiconductor device performs input / output simultaneously on the same pin. And a comparator having means for comparing the response waveform with a third comparison voltage when the semiconductor device does not simultaneously perform input / output on the same pin. The second object is achieved by testing the semiconductor device by comparing the output value with a predetermined expected value.

As described above, if at least three types of driver setting voltages and at least two types of comparison voltages of the comparator are prepared, even in a semiconductor device in which input / output is performed simultaneously on the same pin, the input / output can be set on the same pin. The test can be performed by the same semiconductor test device even if the semiconductor devices are not simultaneously performed.

To perform a test using the same semiconductor test apparatus,
Control means that can switch between the set voltage and the comparison voltage according to the type of the semiconductor device is required. Specifically, control in a driver waveform controller shown in FIG.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a semiconductor test apparatus according to the present invention.

In FIG. 1, a semiconductor test apparatus 1 includes a timing generator 2 for generating a predetermined timing signal such as a test waveform, a pattern generator 3 for generating a predetermined pattern such as a test waveform, and the timing generator 2. And a driver waveform controller 4 for controlling an output of a driver 5 described later based on a predetermined timing and a test pattern generated by the pattern generator 3, and outputting a test waveform based on a control signal of the driver waveform controller 4. Driver 5 and a composite waveform of a test waveform on the transmission line 8 and a response waveform from the semiconductor device (hereinafter also referred to as a device under test) (in the case of a semiconductor device that does not perform input / output simultaneously on the same pin) Is an analog comparator 1 which takes the response waveform as an input, compares it with a predetermined comparison voltage, and outputs the comparison result.
The digital comparator 13 compares the output of the analog comparator 10 with 0, an expected value when the device under test operates normally with respect to the test waveform.

The above-mentioned expected value is generated by the timing generator and the pattern generator, and the digital comparator 1
3 is input as appropriate.

The driver 5 further includes three types of set voltages 5a to 5c based on a control signal from the driver waveform controller 4.
And a driver output voltage selector 6 for generating a test waveform by switching between them, and an amplifier 7 for amplifying the generated test waveform.

In order to test a semiconductor device in which input / output is performed in a time-division manner with the same pin, three types of voltages Vhi1 and Vlow1 in the input mode of the semiconductor device and Vt (termination voltage) in the output mode of the semiconductor device (5a). 5c) are required. However, in order to test a semiconductor device in which input / output is performed simultaneously on the same pin, it is not necessary to set the termination voltage. Therefore, two types of setting voltages Vhi1 and Vlow1 may be used.

The analog comparator 10 further receives a comparison voltage 1 based on a control signal from the driver waveform controller 4.
A comparison voltage selector 11 for switching between 0b and 10c, and a comparator 12 for comparing the comparison voltage with the above-described composite waveform (a response waveform in the case of a semiconductor device that does not perform input / output at the same pin simultaneously). You.

The reference voltages 10b and 10c have a fixed relationship with the aforementioned set voltages Vhi1 and Vlow1,
Set w2.

In the case of a semiconductor device in which input / output is not performed simultaneously at the same pin, since the response waveform becomes the input of the analog comparator, this constant relationship is unnecessary.
An arbitrary set voltage may be set.

As described above, in this embodiment, the setting voltage of the driver and the comparison voltage of the analog comparator are switched by the timing signal from the timing generator and the pattern generator, and the control signal generated based on the pattern.

The control signal from the driver waveform controller 4 is
The signal is sent to the analog comparator via the OR circuit 14, but may be any circuit configuration that switches the reference voltage selector of the analog comparator 10 in synchronization with the switching operation of the driver output voltage selector 6 of the driver 5.

The control signal (control contents) of the driver waveform controller 4 is as shown in FIG. 2, and the combination of the outputs 4a and 4b of the driver waveform controller causes the driver output voltage 6
a and the output of the comparator comparison voltage 11a are set.

For example, the output 4a of the driver waveform controller: H
igh, 4b: Low, the driver output voltage 6a is 5a,
The comparator comparison voltage 11a is controlled to select 10c.

In FIG. 2, when the outputs 4a and 4b of the driver waveform controller are (High, Low) and (Low, Low), this is a mode in which a test waveform is output from the driver. When 6a is 5a, a constant relationship is provided so that the comparator comparison voltage 11a always becomes 10c.

The outputs 4a, 4b of the driver waveform controller
Are (High, High) and (Low, High) when the response waveform is output from the semiconductor device, and the driver output voltage 6a, 5c, is set to be the termination voltage. This mode is used in the case of a semiconductor device that does not perform input / output simultaneously with the same pin. (Hi
gh, High) and (Low, High) perform the same operation.

By switching the control contents shown in FIG. 2 at the timing from the timing generator 2 based on the pattern from the pattern generator 3, the driver 5 can create a test waveform necessary for testing the semiconductor test apparatus, The comparison voltage of the comparator can also be switched in synchronization with the timing.

However, the set voltage 5a of the driver and the output voltage 5d of the driver when the set voltage is set to 5a do not necessarily have to be the same voltage value. Driver setting voltage 5
The same applies to b and 5c. Further, the comparison voltage 10b of the analog comparator and the output voltage 11 of the comparison voltage selector of the analog comparator when the comparison voltage 10b is selected.
a does not necessarily have to be the same voltage value. The same applies to the comparison voltage 10c. Hereinafter, the driver output voltage 5d and the output voltage 11 of the comparison voltage selector of the analog comparator
The description will be made on the assumption that both a have the same voltage value as the set voltage and the comparison voltage.

In order to test only a semiconductor device which simultaneously performs input / output at the same pin, the semiconductor test apparatus may have at least two types of driver output voltages 6a, and control by the driver waveform controller 4 (4a, 4b). There is no problem if the contents are equivalent to (High, Low) and (Low, Low) in FIG.

Using the timing chart shown in FIG.
The operation of each part of the semiconductor test apparatus when the driver 5 and the device under test 9 of the semiconductor test apparatus 1 output signals asynchronously (input / output simultaneously with the same pin) will be described in detail.

FIG. 3 shows the output of the driver 5 (test waveform).
5d, output of device under test (response waveform) 9a, input of analog comparator (composite waveform of test waveform and response waveform) 1
0a, the comparison voltage 11a selected by the comparison voltage selector, and the output 10d of the analog comparator 10 are shown.

Before time t1, the driver waveform controller outputs control signals 4a: Low and 4b: Low. The input voltage 10a of the analog comparator is V1 determined by the voltage value 5a of the driver output voltage 5d, the driver output resistance 20, the voltage value VL of the output voltage 9a of the device under test, and the output resistance 21 of the device under test. Become.

Since the voltage value of the input voltage 10a of the analog comparator is lower than the voltage value 10c of the output voltage 11a of the comparison voltage selector, the output 10d of the analog comparator becomes VcL.

At time t1, the driver waveform controller outputs control signals 4a: Hi, 4b: Low (not shown).

According to the control pattern shown in FIG.
Is switched from the set voltage 5b to the set voltage 5a, and the output voltage 11a of the comparison voltage selector of the analog comparator is similarly switched to the voltage value 10c.

In this case, since the voltage value of the output voltage 9a of the device under test is VL, the input voltage 1
0a is the voltage value 5a of the driver output voltage 5d.
V3 determined by the output resistance 20 of the driver, the voltage value VL of the output voltage 9a of the device under test, and the output resistance 21 of the device under test.

Since the voltage value of the input voltage 10a of the analog comparator is lower than the voltage value 10c of the output voltage 11a of the comparison voltage selector, the output 10d of the analog comparator does not change (indicating VcL).

Next, at time t2, the output voltage 9a of the device under test 9 changes from VL to VH. Since the control signal from the driver waveform controller 4 does not change (not shown), the output voltage 5d of the driver 5 and the output voltage 11a of the comparison voltage selector of the analog comparator maintain the state at the time t1. .

Therefore, the input 10 of the analog comparator
The voltage value of a is the voltage value 5a of the output voltage 5d of the driver,
The output resistance 20 of the driver and the output voltage 9a of the device under test
And V4 determined by the output resistance 21 of the device under test.

At this time, since the voltage value of the input voltage 10a of the analog comparator becomes higher than the voltage value 10c of the output voltage 11a of the comparison voltage selector of the analog comparator, the output 10d of the analog comparator changes from VcL to VcH.

Next, at time t3, the control signals 4a: Low and 4b: Low are output from the driver waveform controller (not shown).

According to the control pattern shown in FIG.
Is switched from the set voltage 5a to 5b, and the output voltage 11a of the comparison voltage selector of the analog comparator is switched from the voltage value 10b to the voltage value 10c.

At this time, since the output voltage 9a of the device under test 9 changes from the voltage value VH to the voltage value VL, the input 10a of the analog comparator changes from the voltage value V4 to the voltage value V1.

The input voltage 10a of the analog comparator
Becomes lower than the output voltage 11a of the comparison voltage selector, so that the output 10d changes from VcH to VcL.

The same applies after time t4.

As described above, if the comparison voltage of the analog comparator is set according to the test waveform, the semiconductor tester 1
Even if the driver 5 and the device under test 9 output signals asynchronously (input and output at the same pin at the same time), the response waveform can be extracted from the composite waveform, so that the test can be performed.

Also, it can be understood from FIG. 3 that if both the driver output voltage and the comparator comparison voltage have two types of set voltages, a semiconductor device that performs input / output simultaneously on the same pin can be tested.

Next, referring to the timing chart shown in FIG. 4, a case where the driver 5 and the device under test 9 of the semiconductor test apparatus 1 alternately output signals (when the same pin inputs and outputs time-divisionally). The operation of each section of the semiconductor test apparatus will be described in detail.

In this embodiment, the output voltage of the driver 5 is set to 5a
5c are prepared, and 5c is set to a value substantially equal to the terminal voltage of the device under test. This is because the present embodiment performs input and output to the device under test in a time-sharing manner. When a response waveform is output from the device under test, the output of the driver is applied to the termination voltage determined by the device under test. Set.

FIG. 4 shows the output (test waveform) 5d from the driver 5, the output (response waveform) 9a from the device under test, the comparison voltage 11a selected by the comparison voltage selector, and the output 10d of the analog comparator 10. I have.

Before time t1, the driver waveform controller 4
Output control signals 4a: Hi and 4b: Hi (not shown).

According to the control pattern shown in FIG.
Is the set voltage 5c, and similarly, the output 11a of the comparison voltage selector of the analog comparator has the voltage value 10c.

That is, the output voltage of the driver 5 is set to the termination voltage 5c, and the output mode from the device under test is set.

The output voltage 9a of the device under test 9 has a voltage value VL
Therefore, the input voltage 10a of the analog comparator has the voltage value 5c of the output voltage 5d of the driver, the output resistance 20 of the driver, and the voltage value VL of the output voltage 9a of the device under test.
It becomes V6 determined by the output resistance 21 of the device under test.

At time t1, the control signal from the driver waveform controller 4 does not change (not shown), so that the output voltage 5d of the driver 5 and the output voltage 11a of the comparison voltage selector of the analog comparator are in the state before the time t1. And the output mode from the device under test remains.

At this time, the output voltage 9a from the device under test is
Changes from the voltage value VL to the voltage value VH. The input voltage 10a of the analog comparator includes the voltage value 5c of the output voltage 5d of the driver, the output resistance 20 of the driver, and the voltage value VH of the output voltage 9a of the device under test. , V6 determined by the output resistance 21 of the device under test.

At this time, since the input voltage 10a of the analog comparator becomes higher than the voltage value 10c of the reference voltage 11a, the output 10d changes from VcL to VcH.

Next, at time t2, since the control signal from the driver waveform controller does not change (not shown), the output voltage 5d of the driver 5 and the comparison voltage 11a of the analog comparator change the state before time t1. The output mode from the device under test is maintained.

At this time, the output voltage 9a from the device under test is
Changes from the voltage value VH to the voltage value VL, and the input voltage 10a of the analog comparator becomes V5.

At this time, since the input voltage 10a of the analog comparator becomes lower than the voltage value 10c of the output voltage 11a of the comparison voltage selector, the output 10d changes from the voltage value VcH to the voltage value VcL.

Between time t3 and time t4, the device under test switches from the output mode to the input mode. The output resistance 21 of the device under test 9 becomes high resistance, or the output voltage 9a of the device under test 9 becomes the termination voltage.

Next, at time t4, the control signals 4a: Low and 4b: Low are output from the driver waveform controller (not shown).

According to the control pattern shown in FIG.
Is switched from the set voltage 5c to 5b, and the reference voltage 11a of the analog comparator is switched to the voltage value 10b.

That is, this is a state in which the input mode to the device under test is set.

At this time, the analog comparator etc.
However, since the operation of the analog comparator and the like is unnecessary in the input mode, these values are handled so as to be ignored.

As described above, in the present semiconductor test apparatus, FIG.
By using the control contents shown in (1), not only a semiconductor device that performs input / output simultaneously, but also a test of a semiconductor device that performs input / output switching can be performed.

Next, another embodiment of the present semiconductor test apparatus is shown in FIG.

The difference from the semiconductor device shown in FIG. 1 is that two analog comparators 1 capable of independently setting a comparison voltage are provided.
5 and 16 and a selector 17 for switching the outputs of the two analog comparators according to the signal of the driver waveform controller 4.

In the present semiconductor test apparatus, an analog comparator in which the comparison voltage is independently set is selected according to the test waveform from the driver 5, so that the output voltage of the driver 5 input to the analog comparator and the device under test 9, only the output waveform of the device under test can be extracted from the composite waveform of the output voltages of No. 9 and tested.

FIG. 6 shows a control pattern of the driver waveform controller 4. The control signal switches between the driver output voltage and the selected comparator output.

Using the timing chart shown in FIG.
The operation of each section of the semiconductor test apparatus when the driver 5 and the device under test 9 of the semiconductor test apparatus 1 output signals asynchronously (when input and output are performed simultaneously on the same pin) will be described in detail.

FIG. 7 shows an output (test waveform) 5d from the driver 5, an output (response waveform) 9a from the device under test, and an input (combined waveform of the test waveform and the response waveform) 15a, 16a to the analog comparator. , The set comparator, and the output 17a of the selected analog comparator.

In this embodiment, the comparison voltage set in the analog comparator is 15b (V1 <15b <V2, V
3) and 16b (V2, V3 <16b <V4) are set.

Before time t1, the driver waveform controller outputs control signals 4a: Low and 4b: Low. Analog comparator input voltages 15a, 16a
Is V1 determined by the voltage value 5a of the output voltage 5d of the driver, the output resistance 20 of the driver, the voltage value VL of the output voltage 9a of the device under test, and the output resistance 21 of the device under test.

As the output of the analog comparator, the output 15c of the analog comparator 15 is selected. Since the voltage value of the input voltage 15a of the analog comparator is lower than the comparison voltage value 15b of the analog comparator 15,
The output 15c of the analog comparator 15 becomes VcL, and the output 17a of the selector 17 also becomes VcL.

At time t1, the driver waveform controller outputs control signals 4a: Hi, 4b: Low (not shown).

According to the control pattern shown in FIG.
The output voltage 5d is switched from the set voltage 5b to the set voltage 5a, and similarly, the output 16c of the analog comparator 16 is selected as the output of the analog comparator.

In this case, since the voltage value of the output voltage 9a of the device under test is VL, the input voltage 1
The voltage values of 5a and 16a are the voltage value 5a of the output voltage 5d of the driver, the output resistance 20 of the driver, the voltage value VL of the output voltage 9a of the device under test, and the output resistance 2 of the device under test.
It becomes V3 determined by 1.

Since the voltage value of the input voltage 15a of the analog comparator is lower than the comparison voltage value 15b, the output 15c of the analog comparator becomes VcL, and the voltage value of the output 17a of the selector 17 does not change (indicating VcL).

Next, at time t2, the output voltage 9a of the device under test 9 changes from VL to VH. Since the control signal from the driver waveform controller 4 does not change (not shown), the output voltage 5d of the driver 5 and the selected analog comparator output maintain the state at the time t1.

Therefore, the input 15 of the analog comparator
The voltage values of a and 16a are V4 determined by the voltage value 5a of the output voltage 5d of the driver, the output resistance 20 of the driver, the voltage value VH of the output voltage 9a of the device under test, and the output resistance 21 of the device under test. .

At this time, the input voltage 15a of the selected analog comparator 15 is
Therefore, the output 15c of the analog comparator changes from VcL to VcH, and the voltage value of the output 17a of the selector 17 also changes to VcH.

Next, at time t3, the control signals 4a: Low and 4b: Low are output from the driver waveform controller (not shown).

According to the control pattern shown in FIG.
Is switched from the set voltage 5a to 5b, and the output of the selected analog comparator is switched from 16c to 15c.

At this time, since the output voltage 9a of the device under test 9 changes from the voltage value VH to the voltage value VL, the inputs 15a and 16a of the analog comparator change from the voltage value V4 to the voltage value V1.

Input voltage 15 of analog comparator 15
Since a is smaller than the comparison voltage 15b of the analog comparator 15, the output 15c of the analog comparator changes from VcH to VcL, and the output 17a of the selector 17
Also changes to VcL.

The same applies to time t4 and thereafter.

As described above, if the output of the analog comparator is selected according to the test waveform, when the driver 5 of the semiconductor test apparatus 1 and the device under test 9 output signals asynchronously (input and output are performed simultaneously at the same pin). In this case, since the response waveform can be extracted from the composite waveform, the test can be performed.

It can also be understood from FIG. 3 that if both the driver output voltage and the comparator comparison voltage have two types of set voltages, a semiconductor device that performs input / output simultaneously on the same pin can be tested.

Next, referring to the timing chart shown in FIG. 8, the case where the driver 5 and the device under test 9 of the semiconductor test apparatus 1 shown in FIG. The operation of each part of the present semiconductor test apparatus will be described in detail. In this embodiment, the output voltage of the driver 5 is 5a
5c are prepared, and 5c is set to a value substantially equal to the termination voltage of the device under test.

FIG. 8 shows an output (test waveform) 5 d from the driver 5, an output (response waveform) 9 a from the device under test, an input voltage 16 a of the analog comparator 16, and a selector 17.
Output 17a of FIG.

Before time t1, the driver waveform controller 4
Output control signals 4a: Hi and 4b: Hi (not shown).

According to the control pattern shown in FIG.
Is selected as the set voltage 5c, and as the output of the analog comparator, the output 16c of the analog comparator 16 is selected.

That is, the output voltage of the driver 5 is set to the termination voltage 5c, and the output mode from the device under test is set.

The output voltage 9a of the device under test 9 has a voltage value VL.
Therefore, the input voltage 16a of the analog comparator has the voltage value 5c of the output voltage 5d of the driver, the output resistance 20 of the driver, and the voltage value VL of the output voltage 9a of the device under test.
It becomes V6 determined by the output resistance 21 of the device under test.

At time t1, the control signal from the driver waveform controller 4 does not change (not shown), so that the output voltage 5d of the driver 5 and the output of the selected analog comparator maintain the state before time t1. Yes, it remains in the output mode from the device under test.

At this time, the output voltage 9a from the device under test is
Changes from the voltage value VL to the voltage value VH. The input voltage 10a of the analog comparator includes the voltage value 5c of the output voltage 5d of the driver, the output resistance 20 of the driver, and the voltage value VH of the output voltage 9a of the device under test. , V6 determined by the output resistance 21 of the device under test.

At this time, since the input voltage 16a of the analog comparator becomes higher than the comparison voltage 16b, the output 16c changes from VcL to VcH, and the selector 1
7 also changes to VcH.

Next, at time t2, the control signal of the driver waveform controller does not change (not shown).
The output voltage 5d and the output of the selected analog comparator keep the state before the time t1, and remain in the output mode from the device under test.

At this time, the output voltage 9a from the device under test is
Changes from the voltage value VH to the voltage value VL, and the input voltage 16a of the analog comparator becomes V5.

At this time, since the input voltage 16a of the analog comparator becomes lower than the comparison voltage 16b, the output 10d changes from the voltage value VcH to the voltage value VcL.
The output 17a of the selector 17 also changes to VcL.

Between time t3 and time t4, the device under test switches from the output mode to the input mode. The output resistance 21 of the device under test 9 becomes high resistance, or the output voltage 9a of the device under test 9 becomes the termination voltage.

Next, at time t4, control signals 4a: Low and 4b: Low are output from the driver waveform controller (not shown).

In accordance with the control pattern shown in FIG.
Is switched from the set voltage 5c to 5b, and the output of the selected analog comparator is switched from 16c to 15c.

That is, the state is the input mode to the device under test.

At this time, the analog comparator etc.
However, since the operation of the analog comparator and the like is unnecessary in the input mode, these values are handled so as to be ignored.

As described above, in the present semiconductor test apparatus, FIG.
By using the control contents shown in (1), not only a semiconductor device that performs input / output simultaneously, but also a test of a semiconductor device that performs input / output switching can be performed.

As described above, in the present semiconductor test apparatus, by appropriately setting the driver output voltage and the comparator comparison voltage, not only the semiconductor device that performs input / output simultaneously, but also
A test of a semiconductor device performed by switching input / output can be performed.

Further, as another embodiment of the semiconductor test apparatus, as shown in FIG. 9, two analog comparators each having a comparison voltage set therein, and digital comparators provided corresponding to each of the analog comparators. When a configuration including a comparator is provided and a test is performed on an element that performs input / output simultaneously, a set of comparators for comparing with an expected value may be switched according to the Hi voltage and the Low voltage of the driver.

That is, a predetermined expected value may be given to one of the two digital comparators according to the test waveform or the control signal.

Even with such a semiconductor test apparatus, not only a semiconductor device that performs input / output simultaneously, but also a semiconductor device that performs input / output switching can be tested.

In the semiconductor test apparatus described above, the driver 5 is used by switching between two or three types of set voltages, but the number of set voltages to be switched may be more than that.

By increasing the set voltage of the driver 5, the voltage value of the test waveform input to the device under test 9 can be changed in real time by the number of set voltages according to the contents of the test.

Similarly, the analog comparator 10 switches and uses two kinds of comparison voltages, but the comparison voltage to be switched may be higher.

By increasing the comparison voltage of the analog comparator, it is possible to change the number of comparison voltages in real time according to the contents of the test.

When switching the comparison voltage of the analog comparator 10 to the output of the driver control circuit 4 through the OR circuit 14, the OR circuit 14 is not essential for the semiconductor test apparatus 1. The same operation can be performed by setting three comparison voltages of the analog comparator 10 and setting the same voltage to two of them. Also, a combinational circuit other than the logical sum may be used.

Further, the output 4a of the driver waveform controller 4
The relationship between 4b, the output voltage 6a of the driver, and the comparison voltage 11a of the comparator is not limited to the combination of FIG. Similarly, outputs 4a and 4b of the driver waveform controller 4 and output voltages 6a and
The relationship between the outputs of the selected comparators is not limited to the combination shown in FIG. 6, but may be any combination.

As a semiconductor device, any type of memory system and logic system can be tested.

[0138]

According to the present invention, it is possible to perform a test of a semiconductor device which simultaneously performs input / output which has not been possible so far.

Further, according to the present invention, the test of an element that performs input / output simultaneously and the test of an element that performs input / output switching are performed by using the same semiconductor test apparatus, or by using a driver and a comparator of the semiconductor test apparatus. This can be performed without replacing a part including the part.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a semiconductor test apparatus according to the present invention.

FIG. 2 shows outputs 4a and 4b of a driver waveform controller 4, an output voltage 6a of a driver, and a comparison voltage 11a of a comparator.
Relation table

FIG. 3 shows a driver 5 and a device under test 9 of the semiconductor test apparatus 1.
Of each part of the semiconductor test apparatus 1 when the signal is output asynchronously

FIG. 4 shows a driver 5 and a device under test 9 of the semiconductor test apparatus 1.
Of each part of the semiconductor test apparatus 1 when signals are output alternately

FIG. 5 is a block diagram showing another embodiment of the semiconductor test apparatus according to the present invention.

FIG. 6 is a relational table between outputs 4a and 4b of a driver waveform controller 4, an output voltage 6a of a driver, and an output of a selected comparator.

FIG. 7 shows a driver 5 and a device under test 9 of the semiconductor test apparatus 1.
Of each part of the semiconductor test apparatus 1 when the signal is output asynchronously

FIG. 8 shows a driver 5 and a device under test 9 of the semiconductor test apparatus 1.
Of each part of the semiconductor test apparatus 1 when signals are output alternately

FIG. 9 is a block diagram showing another embodiment of the semiconductor test apparatus according to the present invention.

[Explanation of symbols]

1 ... Semiconductor test equipment, 2 ... Timing generator, 3 ...
... Pattern generator, 4 ... Driver waveform controller, 5 ...
Driver 6, driver output voltage selector 7, amplifier 8, transmission line 9, non-test element 10, analog comparator 11, comparison voltage selector 12,
…… Comparator, 13 …… Digital comparator

Claims (9)

[Claims] 1. A semiconductor test apparatus for applying a test waveform to a semiconductor device that simultaneously performs input / output on the same pin and testing a response waveform thereof, wherein a composite waveform of the test waveform and the response waveform is converted to a predetermined waveform. A semiconductor test apparatus comprising: means for comparing with a comparison voltage; means for setting the predetermined comparison voltage in accordance with the test waveform; and means for comparing the comparison result with a predetermined expected value. 2. A semiconductor test apparatus for applying a test waveform to a semiconductor device which performs input / output simultaneously on the same pin and testing a response waveform thereof, comprising: a timing generator for generating a predetermined timing signal; A pattern generator for creating a test pattern; a driver waveform controller for outputting a predetermined control signal from the timing signal and the test pattern; and a first and a second set voltage that are switched according to the control signal to perform the test. A driver that outputs a waveform, an analog comparator that compares a composite waveform of the test waveform and a response waveform from the semiconductor device with first and second comparison voltages that are switched according to the control signal, and an output of the analog comparator. And a digital comparator for comparing an expected value created by the pattern generator and the timing generator. Semiconductor test equipment. 3. A semiconductor test apparatus for applying a test waveform to a semiconductor device which simultaneously performs input / output on the same pin and testing a response waveform thereof, comprising: a timing generator for generating a predetermined timing signal; A pattern generator for generating a test pattern; a driver waveform controller for outputting a predetermined control signal from the timing signal and the test pattern; and a test waveform by switching first and second set voltages according to the control signal. A first analog comparator for comparing a composite waveform of the test waveform and the response waveform from the semiconductor device with a first comparison voltage; and a composite waveform of the test waveform and a response waveform from the semiconductor device. And a second analog comparator for comparing the first analog comparator or the second analog voltage according to the control signal. Selects the output of the comparator grayed,
A semiconductor test apparatus characterized by comparing the selected output value with a predetermined expected value. 4. A semiconductor test apparatus for applying a test waveform to a semiconductor device that performs input / output simultaneously on the same pin and testing a response waveform thereof, comprising: a timing generator for generating a predetermined timing signal; A pattern generator for generating a test pattern; a driver waveform controller for outputting a predetermined control signal from the timing signal and the test pattern; and a test waveform by switching first and second set voltages according to the control signal. A first analog comparator for comparing a composite waveform of the test waveform and the response waveform from the semiconductor device with a first comparison voltage; and a composite waveform of the test waveform and a response waveform from the semiconductor device. With a second comparison voltage, and a first digital comparator for comparing an output value of the first analog comparator with a predetermined expected value. The semiconductor test apparatus for the Le comparator, a second digital comparator which compares the output value of said second analog comparator with a predetermined expected value, comprising the. 5. A semiconductor test apparatus for applying a test waveform to a semiconductor device and testing a response waveform thereof, wherein first, second, and third set voltages are switched to set the test waveform or a predetermined termination voltage. A driver for outputting, and comparing the first and second comparison voltages that switch a composite waveform of the test waveform and the response waveform according to the test waveform when the semiconductor device simultaneously performs input / output on the same pin. And a comparator having means for comparing the response waveform with a third comparison voltage when the semiconductor device does not simultaneously perform input / output on the same pin, and outputs an output value of the comparator to a predetermined value. A semiconductor test apparatus for testing a semiconductor device in comparison with an expected value. 6. A test method for a semiconductor device, in which a test waveform is applied to a semiconductor device that performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a composite waveform of the test waveform and the response waveform is formed. A method for comparing a comparison voltage set according to the test waveform, and comparing the comparison result with a predetermined expected value. 7. A test method for a semiconductor device, in which a test waveform is applied to a semiconductor device that performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a predetermined timing signal and a predetermined test pattern are used for a predetermined test signal. A control signal is generated, the test waveform is output by switching the first and second set voltages according to the control signal, and a composite waveform of the test waveform and a response waveform from the semiconductor device is converted into the control signal. A method for testing a semiconductor device, comprising: comparing first and second comparison voltages that are switched in response to each other; and comparing the output with a predetermined expected value. 8. A test method for a semiconductor device, in which a test waveform is given to a semiconductor device that performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a predetermined timing signal and a predetermined test pattern are used for a predetermined test signal. A control signal is generated, the test waveform is output by switching between first and second set voltages according to the control signal, and a composite waveform of the test waveform and a response waveform from the semiconductor device is converted into a first comparison voltage. And each of the second comparison voltages, and selects either the comparison result with the first comparison voltage or the comparison result with the second comparison voltage according to the control signal, and the selected A method for testing a semiconductor device, comprising comparing an output value with a predetermined expected value. 9. A test method for a semiconductor device, in which a test waveform is given to a semiconductor device which performs input / output simultaneously on the same pin and a response waveform thereof is tested, wherein a predetermined timing signal and a predetermined test pattern are used for a predetermined test signal. Generating a control signal, outputting the test waveform by switching the first and second set voltages according to the control signal, and combining the test waveform and the composite waveform from the semiconductor device with a first comparison voltage and a second A method for testing a semiconductor device, comprising: comparing a comparison result with each of comparison voltages; and comparing a comparison result with the first comparison voltage and a comparison result with a second comparison voltage with predetermined expected values.