JPH0829472A - Method for checking conformity of signal line - Google Patents

Abstract

PURPOSE:To readily perform short-circuit inspection for signal lines on a circuit board without breaking a mounted semiconductor integrated circuit, relating to a method for checking the conformity of the signal lines on the circuit board. CONSTITUTION:When a switch 15 is turned on, an inspecting voltage e is applied to a semiconductor-circuit power terminal (VEE terminal) 10, and a voltage at a power terminal (VTT terminal) 11 for a signal terminal is measured using a voltmeter 13. When no short circuit occurs between each signal line 4, 5, 6 and the VEE terminal 10, the voltage measured is 0 [V], whereas when a short circuit occurs, the same voltage value e as that applied to the VEE terminal 10 is obtained as a measurement. Therefore, short-circuit inspection can be carried out between the signal line and the semiconductor circuit power terminal (VEE terminal).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal wiring quality inspection method, and more particularly to a signal wiring quality inspection method provided on a circuit board on which a semiconductor integrated circuit is mounted.

[0002]

2. Description of the Related Art Conventionally, when conducting a pass / fail inspection of a signal wiring provided on a circuit board on which a semiconductor integrated circuit or the like is mounted, each portion of the signal wiring on the circuit board to be inspected,
Whether there is a disconnection or short circuit in each part of the signal wiring by setting a conductive needle such as a spring pin on each of the power supply terminal and ground terminal and measuring the resistance value between each pin using an in-circuit tester etc. In general, it has become difficult to secure a space for erecting spring pins with the increase in density of circuit boards in recent years, so it is necessary to inspect the quality of signal wiring without using spring pins. Boundary scan (IEEE Std 1149.1) is increasingly being used as an easy method.

[0003]

However, the above-described method of inspecting the quality of the signal wiring by the boundary scan is an inspection method utilizing a test circuit built in the semiconductor integrated circuit in advance, and is used for performing the inspection. Must supply power to this test circuit. That is, since it is actually necessary to supply power to the test circuit in the semiconductor integrated circuit through the circuit board to be inspected, there is a short circuit between the signal wiring provided on the circuit board and the power supply terminal or the ground terminal. In this case, there is a risk that the mounted semiconductor integrated circuit may be destroyed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and to detect the presence or absence of a short circuit between a signal wiring provided on a circuit board and a power supply terminal or a ground terminal in a mounted semiconductor integrated circuit. An object of the present invention is to provide a quality inspection method of a signal wiring which can be easily detected without being destroyed.

[0005]

In order to achieve the above-mentioned object, a signal wiring quality inspection method according to the present invention is an inspection method for maintaining all semiconductor circuits constituting a semiconductor integrated circuit in a cutoff state. A voltage for power supply / ground short circuit detection having a limiting voltage satisfying a cutoff current of the semiconductor circuit, and applying the test voltage to a power supply terminal of the semiconductor integrated circuit, and the semiconductor. Whether or not there is a voltage at the terminal end of the signal wiring provided on the circuit board on which the integrated circuit is mounted, or whether the inspection voltage is applied to the terminal and the voltage at the power supply terminal is present Is determined to detect a short circuit between the power supply terminal and the signal wiring.

As another method, for example, for all the semiconductor circuits forming the semiconductor integrated circuit, a test voltage for maintaining the cutoff state of the semiconductor circuit and a limiting current satisfying the cutoff current of the semiconductor circuit are set. Using the power supply / grounding short-circuit detection voltage source that is provided, the inspection voltage is applied to the termination portion of the signal wiring provided on the circuit board on which the semiconductor integrated circuit is mounted, and the ground terminal and the termination portion are provided. By detecting the presence or absence of a current between and, the short circuit between the ground terminal and the signal wiring is detected.

[0007]

The operation based on the above configuration will be described.

According to the quality inspection method of the signal wiring of the present invention, for all the semiconductor circuits that constitute the semiconductor integrated circuit,
With respect to the power supply terminal of the semiconductor integrated circuit, using a power supply / ground short-circuit detection voltage source having a test voltage for maintaining the semiconductor circuit in the cutoff state and a limiting current satisfying the cutoff current of the semiconductor circuit. Whether the voltage for inspection is applied and the presence or absence of a voltage at the terminal of the signal wiring provided on the circuit board on which the semiconductor integrated circuit is mounted is determined, or the voltage for inspection is applied to the terminal. Since a short circuit between the power supply terminal and the signal wiring is detected by determining the presence or absence of a voltage at the power supply terminal while applying, a voltage is simultaneously applied to a plurality of power supply terminals due to a short circuit between the power supply terminals. Even when it ’s gone
It is possible to prevent damage to the semiconductor circuit by supplying the inspection voltage that keeps the mounted semiconductor circuit in the cut-off state, and to confirm that there is no short-circuit if no voltage is detected at the terminal end. When the voltage is detected, it can be known that each of them is short-circuited.

As another method, for example, for all the semiconductor circuits forming the semiconductor integrated circuit, a test voltage for maintaining the cutoff state of the semiconductor circuit and a limiting current satisfying the cutoff current of the semiconductor circuit are set. Using the power supply / grounding short-circuit detection voltage source that is provided, the inspection voltage is applied to the termination portion of the signal wiring provided on the circuit board on which the semiconductor integrated circuit is mounted, and the ground terminal and the termination portion are provided. Since a short circuit between the ground terminal and the signal wiring is detected by determining the presence / absence of a current between and, even when a short circuit current flows due to a short circuit between the power supply terminal and the ground terminal. The current value is limited so that the breaking current of the semiconductor circuit is satisfied, and the damage that occurs in the short-circuited part can be minimized, and the ground terminal and the termination part That no current is short-circuited when not detected, if the constant current is detected that is shorted, can be known, respectively.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a signal wiring quality inspection method of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a circuit configuration diagram for explaining detection of a short circuit between a power supply terminal of a semiconductor integrated circuit and a signal wiring to be inspected in the method of inspecting the quality of a signal wiring of the present invention. In the figure, 1 is a circuit board under test having a signal wiring to be inspected, 2 and 3 are ECL (Emitter-Coupled-Logic) semiconductor ICs mounted on the circuit board under test 1, 4,
5, 6 are signal wirings, 7 and 8 are terminating resistors, 9 is a ground terminal (VCC terminal), and 10 is a semiconductor circuit power supply terminal (VE
E terminal), 11 are signal terminating power supply terminals (VT) to which the signal wirings 4 and 5 are connected via terminating resistors 7 and 8.
T terminal, which corresponds to the terminal portion in the claims). Also,
12 is a voltage source having a current limiting function, 13 is a voltmeter, 1
5 is a switch.

In FIG. 1, the output voltage of the voltage source 12 is E
The CL semiconductor ICs 2 and 3 are set in advance to the inspection voltage (e) in the range where the cutoff state is maintained, and the current limit value is set to the limit current in the range where the cutoff current is also satisfied. Then, when the switch 15 is turned on, the inspection voltage (e) is applied to the VEE terminal 10, so that in this state V
The voltage at the TT terminal 11 is measured using the voltmeter 13. At this time, if there is no short circuit between the signal wirings 4, 5, 6 and the VEE terminal 10, the voltage measurement result is 0 [V].
However, if there is a short circuit, the same voltage value (e) as that applied to the VEE terminal 10 is obtained as the measurement result.
This enables signal wiring and semiconductor circuit power supply terminals (VEE
It is possible to perform a short circuit inspection with the (terminal). Further, the positions of the voltage source 12 and the voltmeter 13 in FIG. 1 are exchanged, and the inspection voltage (e) is applied to the semiconductor circuit power supply terminal (VEE terminal) 10.
The same short-circuit inspection can be performed by applying the voltage and measuring the voltage at the signal terminal power supply terminal (VTT terminal) 11.

FIG. 2 is a circuit configuration diagram for explaining detection of a short circuit between the ground terminal and the signal wiring to be inspected in the signal wiring quality inspection method of the present invention. In the figure,
The same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Further, 14 is an ammeter. Also in FIG. 2, as in FIG. 1, the output voltage of the voltage source 12 is the inspection voltage (e) in the range in which the ECL semiconductor ICs 2 and 3 maintain the cutoff state, and the current limit value is in the range that also satisfies the cutoff current. Set the current limit in advance. Then, when the switch 15 is turned on, the inspection voltage (e) is applied to the VTT terminal 11, so in this state, the ground terminal (VCC terminal) 9 and the signal terminating power supply terminal (VTT terminal).
The current between 11 and 11 is measured using the ammeter 14. At this time, when there is no short circuit between the signal wirings 4, 5, 6 and the VCC terminal 9, the current measurement result is 0 [A], but when there is a short circuit, it is applied to the VTT terminal 11. A current value determined by the voltage value (e) and the termination resistance value (r: not shown) is obtained as the measurement result. Accordingly, it is possible to perform a short circuit inspection between the signal wiring and the ground terminal (VCC terminal).

As described above, according to this embodiment, the signal terminal power supply terminal (VTT) which is the terminal portion of the signal wirings 4, 5, and 6.
Terminal) 11, power supply terminal for semiconductor circuit (VEE terminal) 1
0, the ground terminal (VCC terminal) 9 is connected to the measurement system by simply connecting all the signal wiring and the semiconductor circuit power supply terminal (VEE terminal) 10 or the ground terminal (VCC terminal) 9 The presence or absence can be inspected. Further, the output voltage of the voltage source 12 is preset to the inspection voltage (e) in the range in which the ECL semiconductor ICs 2 and 3 maintain the cutoff state, and the current limit value is preset to the limited current in the range to satisfy the cutoff current. Therefore, erroneous determination due to wraparound of the semiconductor circuit is prevented, and even when there is a short circuit between the signal wiring and the VEE terminal 10 or the VCC terminal 9, the mounted ECL semiconductor IC or the circuit board under test is Damage can be prevented.

In this embodiment, the voltmeter and the ammeter are used to determine the presence or absence of a short circuit. However, the presence or absence of a short circuit can be determined by using a device that can only determine the threshold value that detects only the presence or absence of voltage or current. You may judge.

[0016]

As described above in detail, according to the quality inspection method of the signal wiring of the present invention, for all the semiconductor circuits constituting the semiconductor integrated circuit, the inspection voltage for keeping the semiconductor circuit in the cutoff state and A power supply / ground short-circuit detection voltage source having a limiting current satisfying a cut-off current of the semiconductor circuit, and applying the inspection voltage to a power supply terminal of the semiconductor integrated circuit, and The presence or absence of a voltage at the terminal end of the signal wiring provided on the mounted circuit board is determined, or the presence or absence of the voltage at the power supply terminal is determined by applying the inspection voltage to the terminal end. By doing so, a short circuit between the power supply terminal and the signal wiring is detected, so that a voltage is simultaneously applied to a plurality of power supply terminals due to a short circuit between the power supply terminals. Even when the semiconductor circuit is mounted, the inspection voltage that keeps the mounted semiconductor circuit off is supplied, preventing damage to the semiconductor circuit and not causing a short circuit if no voltage is detected at the terminal end. Therefore, when a constant voltage is detected, it is possible to know that each is short-circuited.

As another method, for example, for all the semiconductor circuits forming the semiconductor integrated circuit, a test voltage for maintaining the cutoff state of the semiconductor circuit and a limiting current satisfying the cutoff current of the semiconductor circuit are set. Using the power supply / grounding short-circuit detection voltage source that is provided, the inspection voltage is applied to the termination portion of the signal wiring provided on the circuit board on which the semiconductor integrated circuit is mounted, and the ground terminal and the termination portion are provided. Since a short circuit between the ground terminal and the signal wiring is detected by determining the presence / absence of a current between and, even when a short circuit current flows due to a short circuit between the power supply terminal and the ground terminal. The current value is limited so that the breaking current of the semiconductor circuit is satisfied, and the damage that occurs in the short-circuited part can be minimized, and the ground terminal and the termination part That no current is short-circuited if not detected, that it is short-circuited when the constant current is detected, the effect that it is possible to know each obtained.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram for explaining detection of a short circuit between a power supply terminal of a semiconductor integrated circuit and a signal wiring to be inspected in a signal wiring quality inspection method of the present invention.

FIG. 2 is a circuit configuration diagram for explaining detection of a short circuit between a ground terminal and a signal wiring to be inspected in the signal wiring quality inspection method of the present invention.

[Explanation of symbols]

 1 circuit board under test 2, 3 ECL semiconductor IC 4, 5, 6 signal wiring 7, 8 termination resistor 9 ground terminal (VCC) 10 power supply terminal for semiconductor circuit (VEE) 11 power supply terminal for signal termination (VTT) 12 voltage source 13 Voltmeter 14 Ammeter 15 Switch

Claims (1)

[Claims] 1. A power supply / ground short-circuit detection circuit for all semiconductor circuits constituting a semiconductor integrated circuit, having a test voltage for maintaining the cutoff state of the semiconductor circuit and a limiting current satisfying a cutoff current of the semiconductor circuit. A voltage source for applying the inspection voltage to the power supply terminal of the semiconductor integrated circuit, and checking the presence / absence of a voltage at the terminal end of the signal wiring provided on the circuit board on which the semiconductor integrated circuit is mounted. It is possible to detect a short circuit between the power supply terminal and the signal wiring by judging or by applying the inspection voltage to the terminal portion and judging the presence or absence of the voltage at the power supply terminal. A characteristic inspection method for signal wiring.