JPS61127143A - Analyzing method for trouble on semiconductor device - Google Patents

Abstract

PURPOSE:To facilitate detection of the place of trouble as well as to contrive reduction in period of inspection by a method wherein a semiconductor device is burnt. CONSTITUTION:An analyzing device has a current source 3, a voltmeter 4 and the control circuit 5 to be used for them, the oxide film located on the surface of the device 1, consisting of a plurality of MOS transistors 7, is broken by a probe 6, and a pulse current of identical waveform is applied from a drain. The pulse peak of drain voltage is monitored by the voltmeter 4 while a current is being applied, and defective articles are broken down successively. This changing rate is read by the control circuit 5. The rate of voltage drop increases remarkably under the condition wherein the burning of the semiconductor device is in the degree which can be visually observed, and when the voltage drop rate reaches the set value, the application of current is stopped by the control circuit 5. The size and width of the pulse are set in accordance with the degree of the trouble, the average value of current is adjusted, and a trouble analyzation can be performed accurately for the extent of trouble occurred on various semiconductor devices.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a failure analysis method for a semiconductor device, and more particularly to a method for analyzing failure of a semiconductor device.
The present invention relates to a failure analysis method for a semiconductor device, such as an S-FET (S-FET) or a power bibolar trannostar, in which the failure location is discovered by burning out when the failure occurs in a pressure deterioration mode of the semiconductor device.

BACKGROUND ART Conventionally, when breakdown voltage deterioration occurs in a semiconductor device such as a MOS-FET or a power polar transistor, it has been necessary to find the location of the failure in order to improve its reliability. Taking a MOSFET as an example, a MOS-FET is usually manufactured as a collection of many small transistors, with as few as 1,110 small transistors and as many as 10,000 or more small transistors housed in one chip. When this transistor's breakdown voltage deteriorated, it was necessary to find out which part of this transistor had failed.

Conventionally, the sealing resin on the surface of a failed device is removed, and then the surface is observed under a microscope. If the location of the failure is unknown, one layer at a time is removed from the surface and observed under a microscope. It's here.

With such prior art, it may or may not be discovered depending on the level of skill of the person performing the ritual, and in some cases, it may not be possible to discover it even if a considerable number of people observe it. Therefore, the reliability of the device has deteriorated. Furthermore, the amount of time it takes to discover a single failure is extremely large, which is not desirable from the viewpoint of workability or α.

Purpose The purpose of the present invention is to solve the above-mentioned technical problems, to easily find a faulty part by burning out a faulty semiconductor device, and to minimize the inspection time for finding faults. An object of the present invention is to provide a failure analysis method for a semiconductor device that can reduce the number of failures.

Embodiment FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The analysis device i2 for analyzing failures in the semiconductor device rM1 includes a current source 3 for applying current, a voltmeter 4, and a control circuit realized by, for example, a microcomputer to control the current [3 and the voltmeter 4]. 5. Semiconductor equipment! ! Probe needle 6 that transmits the current from the electric current 1ma3 to 1
Semiconductor equipment r! 11 is made up of a plurality of small most lannostas 7. The probe needle 6 is a semiconductor device i
A current is applied from the drain by breaking through the oxide film covering the surface of t1.

FIG. 2 shows a semiconductor analysis system r! according to the present invention. 12 is an electrical circuit diagram of the semiconductor device 111 when failure analysis is performed using the semiconductor device 112. FIG. A pulsed overcurrent is applied from the drain of the semiconductor device 1 by the current source 3 as shown in FIG. A voltage corresponding to this overcurrent is measured by a voltmeter 4. Semiconductor equipment RA1! @2 As shown in Figure (2), several small Most Rannostars 7 are connected in parallel, and one
It consists of two power transistors. For example, if the failure of the semiconductor device 1 can be estimated to some extent, a pulse current having the same waveform as shown in FIG. 3(1) is applied, and while such a pulse current is applied, The drain voltage measured by the voltmeter 4 is monitored to a pulse peak value, and the defective products are sequentially destroyed, and the rate of change is read by the processing circuit 5.In a state where the product is burnt out to the extent that it can be visually observed by a worker, When the voltage drop rate becomes extremely large and reaches a predetermined value, the current is stopped by the processing circuit 5. In this way, when the drain voltage is measured by the voltmeter 4 and it is detected that the degree of voltage drop is far from a predetermined value, the current application is immediately stopped to detect the defective location of the semiconductor device lt1. It is possible to cause burnout to such a degree that it can be seen with the naked eye, thus making it possible to easily find the defective location. Therefore, the problem that conventional manual detection fails and the defective location disappears, making it impossible to analyze the cause of the defect, is solved.

Semiconductor equipment ii! 1, if it is not obvious from the outside that it is malfunctioning, then a step-like pulse current as shown in FIG. 3 (2) is applied. In this way, it is possible to bring the damaged portion of the semiconductor device 111 into a burnt-out state that is visible to the naked eye in a short period of time.

In this way, when the rate of change in drain voltage reaches a predetermined value, the current is immediately stopped, thereby preventing excessive burnout of the faulty part and achieving a moderate tube damage condition. becomes possible.

In addition, since the processing circuit 5 causes the current source 3 to generate a desired pulse current, the magnitude and width of the pulse can be set depending on the type of semiconductor device and the degree of failure. Therefore, since the average value of the current can be easily adjusted, it is possible to suitably implement a failure analysis method for a wide range of semiconductor devices.

Effects As described above, according to the present invention, since the voltage corresponding to the overcurrent flowing through the semiconductor device is measured, it is possible to easily detect the burnt state of a faulty part, and therefore anyone can easily visually observe it. It becomes possible to excessively burn out the failure location to the extent that it is possible to do so. Furthermore, since a pulsed current is used, the average value of the current can be easily adjusted, and therefore various semiconductors can be used. It becomes possible to reliably perform failure analysis even for II and various failure degrees.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a semiconductor device 1 when analyzed using a failure analysis device.
FIG. 3 is a circuit diagram of the semiconductor device r! 11 is a waveform diagram of a pulse current applied to the circuit 11. FIG.

Claims (1)

[Claims] 1. A failure analysis method for a semiconductor device, characterized in that a pulsed overcurrent is passed through the semiconductor device, and a voltage corresponding to the current is measured while burning out a portion through which the overcurrent flows.