JPS62144339A - Inspection method of semiconductor device - Google Patents

Abstract

PURPOSE:To detect the cause of defective withstanding voltage easily without destroying a semiconductor device to be inspected by applying a magnetic field to the semiconductor device to be inspected together with voltage and measuring the light emission of the semiconductor device to be inspected. CONSTITUTION:Light emission at positions where withstanding voltage is low is increased by a magnetic field by the defect of a semiconductor element. Consequently, the characteristic of said positions can be inspected by low voltage. In a protective-film detective section 8, 15V applied voltage is required in order to observe light emission when a magnetic field is not applied, but light emission is observed by 7V applied voltage when the magnetic field is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for testing semiconductor devices, and more particularly to a method for testing semiconductor devices for breakdown voltage defects using fL polar light.

Conventional technology Conventionally, for example, to measure the withstand voltage of a GaAs FET, there are methods that use a curve tracer to project the voltage-current characteristics on a display and read the voltage value at a specific current value, and methods that use a constant current power source to measure the gate junction. A commonly known method is to use a voltmeter to measure the potential difference between junctions when a specific current is passed in the opposite direction.

In addition, when a voltage higher than the voltage at which the semiconductor device under test operates is applied, so-called electroluminescence is seen from the junction, and by measuring the amount of light emission and the location of the light emission, it is also possible to find locations with breakdown voltage defects. .

Problems to be Solved by the Invention With the conventional method of measuring the breakdown voltage of the entire semiconductor device using voltage-current characteristics, it has been impossible to identify locations with breakdown voltage defects.

Furthermore, in the testing method using electroluminescence, a high voltage is applied to increase the amount of light emitted by the semiconductor device to be tested, which poses a risk of destruction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device testing method that solves the problems of the conventional method described above.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is a method of testing a semiconductor device in which a voltage and a magnetic field are applied to the semiconductor device to be tested and the light emission of the semiconductor device to be tested is measured.

Effect: According to the method of the present invention, light emission at a location where the breakdown voltage is low due to a defect in a semiconductor element is enhanced by a magnetic field. Therefore, it is possible to inspect the same location using a low voltage.

Embodiment FIG. 1 shows a plan view of a GaAs FET and the direction of a magnetic field to increase the amount of light emitted. In the figure, 1 is a gate, 2 is a source, 3 is a drain, 4 is an active layer region, and 5
is the gate finger. When a magnetic field of the magnitude shown in the figure is applied, for example, if a reverse voltage of 12 cm is applied to the gate 1 of the FET, the gate finger 5 and the drain 3
Light emission can be seen in the gate light emitting region between the two, but when no magnetic field is applied, a voltage of 26 V is required to observe the same light emission.

FIG. 2 is a plan view showing a light emitting turn caused by mask displacement, and the same components as in FIG. 1 are given the same numbers. When no magnetic field was applied, an applied voltage of 20 V was required to observe luminescence, but when a magnetic field similar to that in case 1 of FIG. 1 was applied, luminescence was observed when 8 V was applied.

FIG. 3 is a plan view showing a light emission pattern at the protective film defective portion 8, and the same components as in FIG. 1 are given the same numbers. 8 in the figure represents a protective film defect. When no magnetic field was applied, an applied voltage of 16 V was required to observe luminescence, but when a magnetic field similar to that in Figure 1 was applied,
Luminescence was observed at 7■.

In addition, Fig. 4 is a plan view showing the light emission pattern of a sample in which the gate breakdown voltage decreased by 10% after 1000 hours of a high temperature operation test (channel temperature 250°C) of a GaAs FET, and it has the same configuration as Fig. 1. have the same number. Conventionally, a voltage of 20V was required to observe luminescence, but when a magnetic field similar to that shown in Fig. 1 was applied, luminescence could be observed with an applied voltage of 10V. In the state before the test, the first
By applying the same magnetic field and voltage of 12V as shown in the figure, light emission from the entire gate was observed as shown in Figure 1.

Then, by continuing the test, the wire broke at the point where light emission was observed at 1000 hours, and the FET
is no longer working properly.

In this way, it was possible to predict failures due to gate disconnections by examining the light emitting locations, but with the conventional method that did not apply a magnetic field, 7 out of 20 gates were burnt out and destroyed, but according to this example, 40 gates were destroyed. I was able to inspect everything without destroying it.

The above has described the case of GaAs FET, but the present invention can also be applied to the 81 semiconductor device because light emission occurs when a high voltage exceeding the operating voltage is applied to the 81 semiconductor device. Needless to say.

Effects of the Invention As is clear from the above description, according to the present invention, the cause of breakdown voltage failure can be easily detected without destroying the semiconductor device under test, and is extremely effective in practice.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the GaAs FET element, the direction of the magnetic field, and the light emission pattern, FIG. 2 is a schematic diagram showing the light emission pattern due to mask misalignment, and FIG. 3 is a schematic diagram showing the light emission pattern at the defective part of the protective film. Figure 4 shows GaAs F E
FIG. 3 is a schematic diagram showing a light emission pattern of a sample whose breakdown voltage has decreased in a high temperature operation test of T. 1...Gate, 2...Source, 3...
...Drain, 4...Active layer region, 5...
. . . Gate finger, 6 . . . Gate light emitting region, 7 . . . Magnetic field, 8 . . . Protection film defect.

Claims (1)

[Claims] 1. A method for testing a semiconductor device, characterized in that when testing a semiconductor device for breakdown voltage defects, the semiconductor device is tested by applying an electric field and a magnetic field at the same time.