JPH05114636A - Semiconductor device - Google Patents

Abstract

PURPOSE:To contrive to enhance efficiency of test and to improve quality and reliability thereof by a method wherein a function of a pull-up resistor and a pull-down resistor is stopped by an external terminal. CONSTITUTION:All terminals containing a pull-up resistor and a pull-down resistor are provided with a Pch MOS transistor on the pull-up resistor side in series with a VDD power supply 18, and an Nch MOS transistor on the pull-down resistor side in series with a VSS power supply 19. These control transistors are semiconductor integrated circuits having a circuit function so that, when a control signal from an external unit is in Hi, both the Pch transistor and Nch transistor may be turned ON, and when the control signal is in Lo, both the Pch transistor and Nch transistor may be turned OFF.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a semiconductor device (hereinafter referred to as IC) inspection method.

[0002]

2. Description of the Related Art Conventionally, an IC having an input terminal with a pull-up resistor as shown in FIG. 2 is inspected with a test pattern for checking the function of each terminal, similarly to an IC having no pull-up resistor. The quality of the IC is judged by performing both a function check (hereinafter referred to as AC measurement) for inputting and verifying an expected output pattern and a current check (hereinafter referred to as DC measurement) flowing in the circuit when a voltage is applied. It was

[0003]

However, in the prior art, when inspecting an IC having an input terminal with a pull-up resistor, there is no particular problem during AC measurement, but a low level is applied to the input terminal during DC measurement. At this time, a current flows through the pull-up resistor, and the current is added to the OFF leak of the transistor, so that the OFF leak of the transistor, which is important for ensuring the reliability of the IC, cannot be accurately measured. is there.

The present invention solves such a problem. An object of the present invention is to add a switch in series to a pull-up resistor or a pull-down resistor and turn off the switch if necessary at the time of inspection. The current flowing through the pull-up resistor or pull-down resistor is cut off, and the IC
It is to improve the quality and reliability of the IC by making it possible to measure only the OFF leak.

[0005]

The semiconductor device of the present invention comprises:
A switch for stopping the function of a pull-up resistor or a pull-down resistor used in a semiconductor integrated circuit is built in on the same semiconductor substrate.

[0006]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 is a circuit diagram of an input terminal portion of a semiconductor device of the present invention. The input terminal 17 connected to the internal gate 11 of the IC has a P terminal connected to the VDD power source 18.
It has an electrostatic protection circuit composed of an electrostatic protection diode 14 on the ch side, an electrostatic protection diode 15 on the Nch side connected to the VSS power supply 19 and an electrostatic protection resistor 16, and also for pulling up the input terminal 17. It has a pull-up resistor 12 and a pull-up control transistor 13 connected in series with the pull-up resistor. The pull-up control transistor 13 is made of a Pch MOS transistor, and serves to electrically disconnect the pull-up resistor 12 from the VDD power source 18 by applying a control signal Hi to the gate.

In an actual application, since there are a plurality of terminals including pull-up resistors and pull-down resistors,
MO of Pch is connected in series with the pull-up resistor on all terminals with pull-up resistor and pull-down resistor.
The S transistor was connected to the VDD power source 18, and the Nch MOS transistor was connected to the VSS power source 19 in series with the pull-down resistor on the pull-down resistor side. Then, these control transistors have a circuit function so that both the Pch transistor and the Nch transistor are turned on when the external control signal is Hi, and both the Pch transistor and the Nch transistor are turned off when the control signal is Lo. . As a result, the pull-up resistor and pull-down resistor can be connected to or disconnected from each power source at the same time by controlling from the external terminal.

When the IC is inspected, the AC measurement can be performed when the external control signal is either Hi or Lo, but when the control signal is Lo, the pull-up resistor and pull-down resistor are disconnected. Since the input status is undefined, the function evaluation may not be possible. To avoid this, it is necessary to fix the input state so that the input state of the terminal with pull-up resistor and the terminal with pull-down resistor does not become undefined. Further, in the case of DC measurement, when the control signal from the outside is Hi, for example, at the input terminal pulled up, the control transistor connected in series to the pull-up resistor is ON, so When the signal at the terminal is in the Lo state, the current flowing from the power supply VDD through the pull-up resistor to the input terminal is added to the current flowing through the ammeter on the VDD side, and the OFF leakage required to secure the reliability of the IC Cannot be measured separately. In such a case, according to the present invention, the control signal from the outside is set to Lo, the pull-up resistor is electrically disconnected, and DC measurement is performed. By doing so, the OFF leakage of the IC can be separated and measured. In addition, the leak of the input terminal can be measured separately.

[0010]

As described above, according to the semiconductor device of the present invention, since the functions of the pull-up resistor and the pull-down resistor of the IC can be stopped, the OFF leak and the input leak of the IC can be measured, and the quality and the reliability can be improved. Can be expected to improve significantly.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an input section of a semiconductor device that is an embodiment of the present invention.

FIG. 2 is a circuit diagram of an input section of a conventional semiconductor device.

[Explanation of symbols]

 11 IC internal gate 12 Pull-up resistor 13 Pull-up control transistor 14 Pch side static electricity protection diode 15 Nch side static electricity protection diode 16 Static electricity protection resistor 17 Input terminal 18 VDD power supply line 19 VSS power supply line 21 IC internal gate 22 Pull Up resistance 23 Pch side static electricity protection diode 24 Nch side static electricity protection diode 25 Static electricity protection resistor 26 Input terminal 27 VDD power supply line 28 VSS power supply line

Claims (1)

[Claims] 1. A semiconductor device comprising a switch for stopping the functions of a pull-up resistor and a pull-down resistor, which are used in a semiconductor integrated circuit, built in on the same semiconductor substrate.