Asymmetric bidirectional silicon controlled rectifier electrostatic discharge device in an interdigital mode and manufacturing method thereof

Abstract

The invention discloses an asymmetric bidirectional silicon controlled rectifier electrostatic discharge device in an interdigital mode. An asymmetric silicon controlled rectifier structure is selected, a path of a protection ring is used as a temporary discharge path for negative pulses, and a problem that a traditional device has a parasitic path of the protection ring can be solved; and the protection grade of the device can be controlled by increasing or decreasing the number of cathodes in a novel interdigital mode. If the device protection grade is high, the number of cathodes is increased; and if the device protection grade is low, the number of cathodes is reduced, and the layout area is saved. The P + of the inner side interdigital is floated, so that the parasitic NPN base resistance of the inner side interdigital is increased; meanwhile, the outer side interdigital is helped be started, so that the conduction speed of the device is increased, and the current distribution ismore uniform; and finally, the maintaining voltage of the whole device is generally determined by the innermost interdigital, so that the problem that the maintaining voltage of the device in the traditional interdigital mode is reduced along with the increase of the interdigital index is solved.

Description

technical field [0001] The invention relates to the field of electrostatic protection, in particular to an interdigitated asymmetric bidirectional thyristor electrostatic discharge device and a manufacturing method thereof. Background technique [0002] With the advancement of semiconductor manufacturing technology, the feature size of the device is continuously reduced and the degree of integration is continuously improved. The design window of SD devices is getting smaller and smaller, and the difficulty is getting more and more difficult. It is necessary to occupy a small chip area and have a good static discharge ability. ESD protection devices have become one of the main problems faced by product engineers. [0003] Silicon Controlled Rectifier (SCR) is a conventional device structure for on-chip ESD protection. Compared with diodes, triodes, and field effect transistors, it has the advantages of high discharge efficiency per unit area, strong robustness, and high prot...

AI Technical Summary

Problems solved by technology

The asymmetric bidirectional SCR device is turned on and maintains a very low voltage due to strong conduction. When the circuit is working normally, it may be unable to be turned off due to static electricity, so that the circuit port maintains a very low voltage, which affects the operation of the core circuit.

Usually, a pair of irreconcilable contradictions when high sustaining voltage and high failure current

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