JPS63147311A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device where each component device can be specified easily and surely by means of an existing inspection apparatus by installing a discriminating circuit part which has an electric characteristic in compliance with the discriminating information at a circuit part for a genuine device. CONSTITUTION:A circuit part, for a genuine device, which generates a prescribed output signal corresponding to an input signal and a discriminating circuit part which has an electric characteristic in compliance with the discriminating information at the circuit part for the genuine device are installed. For example, an internal device 6 at an input-protective circuit for a MOS semiconductor device or the like generates a prescribed output signal, from an output pad, which corresponds to a prescribed input signal coming from an input pad 1. To test a semiconductor device, a forward current is made to flow through protective diodes 3-5 and their forward voltage is measured. In addition, when an electric current is made to flow in such a way that the input pad 1 shows a voltage which is lower than a ground level, the forward voltage causes a difference whose value corresponds to the difference caused by adding the diode 5. If this voltage is measured, it is possible to discriminate which circuit it is from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a semiconductor device, and particularly to a semiconductor integrated circuit formed on a substrate such as silicon wafer 1.

[Prior art]

A large number of semiconductor devices are usually manufactured simultaneously on a semiconductor substrate, that is, a wafer. The manufacturing specifications include cases in which the same type of semiconductor devices are manufactured on the same substrate, and cases in which two or more different types of semiconductor devices are manufactured on the same substrate. In the manufacturing process of semiconductor devices, silicon substrates are treated and inspected as one unit, so in the latter case, it is necessary to treat different semiconductor devices separately, especially in operation tests of semiconductor devices.

A conventional method used to identify semiconductor devices that are mixedly manufactured on the same substrate: record the position of each semiconductor device on paper, etc., and refer to this for identification. Alternatively, there was a method of identification by visual inspection by the worker. These methods are complicated and cannot be used to process large amounts of data by visual identification.

Furthermore, after the semiconductor substrate has been cut and separated into individual semiconductor devices and assembled into a specific package, it cannot be identified by the above-mentioned means.

It becomes possible. Even in this case, if the device exhibits a malfunction, it becomes completely impossible to count the yield, which is important information for managing the manufacturing process of semiconductor devices.

In addition, as another inspection method, since the surface shape of the semiconductor substrate can be easily observed before it is separated and cut from the semiconductor substrate, automatic discrimination is possible by detecting the surface shape using an image input device and a discrimination device. However, after it is assembled into a package, it is necessary to see through it using an X-ray device or the like to make a determination, which makes it even more difficult.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the difficulties of the above-mentioned conventional example and to provide a semiconductor device in which each device can be easily and reliably identified using existing inspection equipment.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIGS. 1 and 2 partially show a circuit of an input terminal portion of a semiconductor device.

1 is an input pad, 2 is an input protection circuit, 3. 4.5 is an input protection diode, and 6 is an internal element. The internal elements are for generating a predetermined output signal from an output pad (not shown) in response to a predetermined input signal from the input pad l.

The semiconductor device shown in FIG. 2 functions similarly to the one shown in FIG. 1 during actual use.

The circuit shown in FIG. 2 is a circuit used as an input protection circuit for MO3 type semiconductor devices, etc., and is used for transportation of the device.

This prevents damage to the internal elements of the semiconductor device by preventing surge voltages applied from the human body or machinery from being applied to the internal elements during assembly work.

The circuit shown in FIG. 1 is different from the circuit shown in FIG. 2 in that a diode on the GND side is added to one measurement column.

Regarding the input protection function, the addition of the diode 4 has almost no effect because large voltages that would cause actual damage to the internal elements are not transmitted to the internal elements in the same way. Also, in actual use, this diode 3.4.5
Since it only acts as a non-conductor with respect to the input voltage, the presence or absence of the diode 5 is almost irrelevant.

When testing semiconductor devices, use an IC tester etc.
Input signals for testing from the input pad. Specifically, a forward current is caused to flow through the protection diode of the input protection circuit, and its forward voltage is measured.

In the circuits of Figures 1 and 2, the input pad is connected to ground (GND).
) When a current is caused to flow so that the potential is lower than the level, a forward voltage difference corresponding to the addition of one diode 5 occurs. By measuring this voltage, it becomes possible to determine from the outside whether the circuit is the one shown in FIG. 1 or the circuit shown in FIG. By determining and manufacturing this combination for each semiconductor device in advance, each semiconductor device can be separated from the substrate and assembled into a package even if it is not cut yet and is lined up on the substrate. By performing electrical measurements on each terminal and detecting a combination of voltage values at each terminal even after the test has been completed, it is possible to easily determine the semiconductor device by comparing it with a predetermined combination. In the test, the input pad 1 may be set at a potential lower than the GND level by a predetermined amount, and the circuit may be determined based on the difference in the current value flowing at that time.

FIG. 4 shows another embodiment of the present invention, in which a diode 5 is provided on the side of the high potential power supply, voltage terminal (VDD), with respect to the input pad.

In the circuit of Figure 4, if the input current for discrimination is passed so that the potential of the input pad is higher than the power supply potential, the voltage at that time will be the voltage equivalent to only one diode compared to the circuit of Figure 2. This makes it possible to distinguish between the circuit of FIG. 2 and the circuit of FIG. 4.

The potential of the input pad may be set higher than the power supply potential by a predetermined amount, and the determination may be made based on the difference in the current value flowing at this time.

〔effect〕

As explained above, by providing a semiconductor device with the above-described additional circuit for identification, automatic handling can be easily and inexpensively performed when managing a wide variety of semiconductor devices for purposes such as manufacturing and sales. It becomes possible to do so. In addition, since an additional circuit for identification is separately provided regardless of whether the main body circuit is good or defective, it can be identified using this, and it is also effective in calculating the defective rate.

[Brief explanation of the drawing]

Figure 1 shows an input circuit with one diode added. Figure 2 shows a normal input circuit.

Claims (3)

[Claims] (1) It is characterized by having a real element circuit section for generating a predetermined output signal in response to an input signal, and an identification circuit section having electrical characteristics corresponding to identification information of the real element circuit section. Semiconductor equipment. (2) The semiconductor device according to claim 1, wherein a current flows through the identification circuit section when the potential state is such that no current flows through the actual element circuit section. (3) The semiconductor device according to claim 1, wherein the identification circuit section has a protection circuit section for preventing a voltage outside a predetermined range from being applied to the actual element circuit section. Device.