JP2007218779A - Test board for semiconductor tester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test board for a semiconductor tester, capable of performing an inspection with higher accuracy and higher reliability than those of the prior inspection, in the inspection of semiconductor integrated circuits. <P>SOLUTION: In the test board for the semiconductor tester, signal wiring suitable for each method for a DC test and a function test is used and the signal wiring is switched, in response to a test method by providing a switching circuit. Also, the signal wiring can be switched without mechanical switching operations, by employing a low-pass filter circuit 110 connected to a DC testing signal wiring 103 as a switching circuit, and by employing a high-pass filter circuit 111 that is connected to a function testing signal wiring 104 as a switching circuit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to inspection of a semiconductor integrated circuit, and more particularly to a test board connected to a semiconductor tester (semiconductor inspection apparatus).

As a test method for a semiconductor integrated circuit, there are a function test for testing a logic operation of the semiconductor integrated circuit and a DC test for measuring electrical characteristics of input / output terminals. Normally, the same input / output terminals are used for the function test and the DC test.

FIG. 4 shows an example of a conventional structural diagram. The semiconductor integrated circuit 101 is connected to a semiconductor tester 106 via a test board 102. One signal line 114 is provided in the test board 102. That is, conventionally, a function test and a DC test, which are test methods for semiconductor integrated circuits, have been performed using a common signal wiring.

Further, for example, as shown in FIG. 1 of Patent Document 1, a BGA package 1 including a semiconductor integrated circuit is connected to a semiconductor inspection device (semiconductor tester) 3 via a test board 6. A function test of the semiconductor integrated circuit is performed by using a driver 11, comparators 16, 17 and the like installed in the semiconductor tester. Although not shown in the figure, in a normal semiconductor tester, a measurement unit capable of performing a DC test is installed and connected to the wiring 14. Similar to the configuration shown in FIG. 4, the semiconductor integrated circuit and the semiconductor tester 3 are connected by a single wiring 10 in the test board 6.

  On the other hand, in Patent Document 2, in order to enable a normal test of LSI and a continuity test of the power supply terminal and the GND terminal on the same test board, the signal terminal and the power / GND terminal of the device under test are switched by a switch in the test board. A configuration for switching is disclosed. Unlike the conventional configuration shown in FIG. 4 or the configuration disclosed in Patent Document 1, this configuration does not use the same signal terminal, but uses a different terminal for each object to be measured.

JP 2004-233171 A JP 2000-171510 A

In recent years, as the input and output terminals of semiconductor integrated circuits have become narrower and more numerous, the conditions for signal wiring used for inspection have become stricter, and it is very common to use multiple test methods with the same signal wiring as in the past. It was difficult. As described below, this is mainly due to the fact that the electrical characteristics required for the signal wiring are greatly different between the function test and the DC test.

In the function test, a pulse signal in a high frequency band is input to a semiconductor integrated circuit to be measured, and a pulse signal output from the semiconductor integrated circuit is determined. In order to accurately transmit and receive the pulse signal, it is important that the characteristic impedance of the test board wiring is normally matched with the wiring for the measurement circuit board mounted on the semiconductor tester.

Here, the characteristic impedance (Zo) is expressed by the following equation as a proportional factor (voltage / current) of a traveling wave voltage and current flowing through the wiring at an arbitrary point on the wiring. Zo is constant regardless of the location on the wiring.
Zo = (L / C) ^1/2
Here, L is an inductance per unit length of the wiring (1 m), and C is a capacitance per unit length of the wiring (1 m).

  When a plurality of circuits are connected to each other, the matching impedance is “matching” if the characteristic impedances of the respective circuits to be connected are the same, and “nonmatching” is not the same. In the case of “non-matching”, there is a problem that signal reflection occurs at the junction of the circuit and distortion of the traveling wave occurs. For this reason, in order to avoid the influence of reflection, the characteristic impedance of the function test signal wiring is usually matched to the measurement circuit on the semiconductor tester side.

On the other hand, the DC test applies a low frequency current to a semiconductor integrated circuit to be measured and measures the voltage at that time. The problem with the DC test is that a voltage drop occurs due to the conductor resistance of the signal wiring, resulting in an error in the measured voltage. Therefore, it is desirable that the signal wiring has as low a conductor resistance as possible. Since the DC test transmits and receives low-frequency signals, there is no need to consider the matching of characteristic impedance as in the function test.

In this way, the characteristics required for signal wiring differ greatly depending on the test method.

Furthermore, with the recent narrowing of the input / output terminal pitch of semiconductor integrated circuits, it is necessary to make the signal wiring thinner than before. If the characteristic impedance of the function test signal wiring is designed to be 50 Ω, for example, for matching with other circuits, the impedance in the low frequency band corresponding to the DC test becomes larger than that. The impedance in the low frequency band is dominated by the conductor resistance of the wiring. Therefore, in the DC test, in addition to the increase in resistance due to the reduction of the wiring width, it is necessary to consider the matching of the signal wiring for function test. Therefore, the problem of the voltage drop due to the increase in the conductor resistance becomes obvious and accurate. It was extremely difficult to measure voltage. Conversely, if priority is given to the DC test and the conductor resistance of the signal wiring is set to be low, matching of the characteristic impedance in the function test becomes difficult.

As described above, the required characteristics are greatly different between the function test and the DC test, and in addition to the recent decrease in the pitch between the input / output terminals of the semiconductor integrated circuit and the increase in the number, the test is common to a plurality of test methods. The use of signal wiring has been a major obstacle to the accurate and reliable inspection of semiconductor integrated circuits.

  According to the present invention, a test board connected to a semiconductor tester and having a plurality of signal wires includes a first signal wire and a second signal wire having a conductor resistance lower than that of the first signal wire, and There is provided a test board for a semiconductor tester comprising a switching circuit between the first signal wiring and the second signal wiring according to a test method.

2. The semiconductor tester according to claim 1, further comprising a high-pass filter circuit connected to the first signal wiring or a low-pass filter circuit connected to the second signal wiring as the switching circuit. For test board, provided.

  The required characteristic of signal wiring differs between a function test and a DC test, which are methods for inspecting a semiconductor integrated circuit. In the present invention, a semiconductor tester test board uses a signal wiring suitable for each test method, includes a switching circuit, and performs switching of the signal wiring according to the test method, thereby providing an accurate and reliable semiconductor integrated circuit. Circuit inspection can be performed.

  Further, by using a high-pass filter circuit connected to the first signal wiring or a low-pass filter circuit connected to the second signal wiring as the switching circuit, the signal wiring can be switched without mechanical switching operation. .

  ADVANTAGE OF THE INVENTION According to this invention, the test board for semiconductor testers which can perform a test | inspection more accurate and reliable than before can be provided in the test | inspection of a semiconductor integrated circuit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A block diagram of the invention is shown in FIG. The semiconductor tester 106 is connected to the semiconductor integrated circuit 101 via the test board 102. In the test board 102, a DC test signal wiring 103, a function test signal wiring 104, and a switching circuit 105 are provided. The conductor width of the DC test signal wiring 103 is made wider than the conductor width of the function test signal wiring 104, thereby reducing the conductor resistance. The function test signal wiring 104 preferably matches the characteristic impedance of the signal wiring used in a measurement circuit board (not shown) mounted on the semiconductor tester 106. In this embodiment, since the characteristic impedance of the signal wiring used for the measurement circuit board is 50Ω, the characteristic impedance of the function test signal wiring is also 50Ω.

A circuit example is shown in FIG. As a switching circuit between the DC test signal wiring 103 and the function test signal wiring 104, a low-pass filter circuit 110 (hereinafter referred to as LPF) connected to the DC test signal wiring 103, and a high-pass filter circuit connected to the function test signal circuit 111 (hereinafter referred to as HPF). The cut-off frequencies of the LPF 110 and the HPF 111 are required to be higher than the frequency of the DC test signal wiring and lower than the function test signal frequency. For example, the LPF 110 having a cutoff frequency of 100 kHz is configured by setting the inductance to 225.079 nH and the capacitance to 56.27 μF. On the other hand, for example, by setting the inductance to 11.254 μH and the capacitance to 46.016 nF, the HPF 111 having a cutoff frequency of 100 kHz can be configured.

The DC test signal 107 at the time of the DC test is transmitted to the semiconductor integrated circuit 102 only through the DC test wiring 103 because the frequency signal of 100 kHz or less is cut off by the HPF 111. The signal flow at this time is illustrated as 107 in FIG. Since the conductor resistance of the DC test signal wiring 103 is set low, fluctuations in measurement values and variations due to voltage drop are reduced.

On the other hand, at the time of the function test, the signal is transmitted to the semiconductor integrated circuit 101 through the path of the DC test wiring 103 and the function test wiring 104 as indicated by 108 and 109 in FIG. The high-frequency signal 109 of 100 kHz or higher included in the function test signal is cut off by the LPF 110, and therefore passes through only the function test wiring 104 and is transmitted to the semiconductor integrated circuit 1 by the HPF 111. Since the function test signal wiring 104 is matched with the characteristic impedance of 50Ω, the high-frequency signal 109 is less reflected and good transmission with less distortion can be performed. Of the pulse waveforms transmitted during the function test, the low frequency signal 108 of 100 kHz or less is transmitted to the semiconductor integrated circuit 101 through the DC test wiring 103 as in the DC test. Since the low frequency signal 108 is not related to the function test, it does not affect the measurement or the circuit operation.

  The DC test signal wiring 103 and the function test signal wiring 104 are switched by using the LPF 110 and the HPF 111 without switching operation according to the test method. Signal wiring suitable for each test method is selected, and signal transmission can be performed smoothly.

In the present embodiment, since wiring suitable for each test method of the function test and DC test is used in the inspection of the semiconductor integrated circuit, the inspection can be performed more accurately and more reliably than before. In this embodiment, the signal wiring is switched using the LPF and the HPF, and can be performed without a mechanical switch operation.

(Second Embodiment)
The second embodiment will be described below with reference to the drawings. This embodiment is different from the first embodiment in that signal wiring is switched using a switching relay. Compared to the first embodiment, since the circuit configuration is simple, there is an advantage that the effective area on the test board can be reduced.

In the circuit shown in FIG. 3, the DC test signal wiring 103 and the function test signal wiring 104 have the same conditions as in the first embodiment, and the switching relay 112 is used for switching the signal wiring. This makes it possible to obtain the same effect as that of the first embodiment.

In this configuration, it is necessary to control the operation of the relay in each of the function test signal and the DC test signal transmission.

As an operation, when performing a DC test, the DC test signal 107 is transmitted to the semiconductor integrated circuit 101 by selecting the DC test signal wiring 103. When performing a function test, the function test signal 113 is transmitted to the semiconductor integrated circuit 101 by selecting the function test signal wiring 104. The switch switching operation can be performed, for example, by program control on the semiconductor tester 106 side.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications are possible and that such modifications are also within the scope of the present invention.

  For example, in the embodiment, only two types of test methods are shown, but it is possible to appropriately cope with the case of three or more types of test methods.

It is a structural diagram in the present invention. 1 is a circuit diagram showing a first embodiment of the present invention. It is a circuit diagram which shows the 2nd Embodiment of this invention. It is an example of a structure figure showing conventional technology.

Explanation of symbols

101 Semiconductor integrated circuit
102 test board
103 DC test signal wiring
104 Signal wiring for function test
105 switching circuit
106 Semiconductor tester
107 DC test signal
108 Function test signal (low frequency signal)
109 Function test signal (high frequency signal)
110 Low-pass filter circuit
111 High-pass filter circuit
112 Switching relay
113 Function test signals
114 Signal wiring

Claims (7)

In a test board connected to a semiconductor tester and having a plurality of signal wirings,
A first signal wiring and a second signal wiring having a conductor resistance lower than that of the first signal wiring;
A test board for a semiconductor tester, comprising a switching circuit for switching between the first signal wiring and the second signal wiring according to a test method. 2. The semiconductor tester according to claim 1, wherein the first signal wiring is a signal wiring for function test using a pulse signal, and the second signal wiring is a signal wiring for DC test. For test board.   2. The test board for a semiconductor tester according to claim 1, wherein the first signal wiring is matched with a characteristic impedance of a signal wiring used for a measurement circuit in the semiconductor tester. A high-pass filter circuit connected to the first signal wiring as the switching circuit;
Or a low-pass filter circuit connected to the second signal wiring,
The test board for a semiconductor tester according to claim 1, comprising:   The cutoff frequency of the high pass filter circuit is higher than a signal frequency transmitted to the second signal wiring and lower than a signal frequency transmitted to the first signal wiring. Test board for semiconductor tester as described.   5. The cutoff frequency of the low-pass filter circuit is higher than a signal frequency transmitted to the second signal wiring and lower than a signal frequency transmitted to the first signal wiring. Test board for semiconductor tester as described.   The test board for a semiconductor tester according to claim 1, wherein a switching relay is used in the switching circuit.

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