Grounded-grid NMOS (N-channel metal oxide semiconductor) unit for antistatic protection and antistatic protection structure thereof

Abstract

The invention provides a GGNMOS (Grounded-Grid N-channel metal oxide semiconductor) unit for antistatic protection, which is of a regular polygon shape, wherein a drain of the GGNMOS unit is closed by a circular grid; the circular grid is surrounded by a source of a regular polygon concentric with the regular polygon; the outer side of the source is provided with a regular polygonal circular substrate grounding area being concentric with the source and having the same distance with any place of the source; and the source and the regular polygonal circular substrate grounding area are evenly spaced by a field oxygen area. And correspondingly, the invention also provides an antistatic protection structure based on the GGNMOS unit. The circular grid is used for closing the drain by changing the plane layout structure of the GGNMOS unit; and resistance values of serially-connected resistors of the base of a parasitic triode are equal by adopting the method of surrounding the source through the concentric substrate grounding area. All ESD (Electronic Static Discharge) protection device units can be uniformly switched on in the antistatic protection structure provided the invention when the static is generated, thus high ESD protection capacity of above HBM 8 kV can be achieved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular, the invention relates to a GGNMOS unit for antistatic protection and an antistatic protection structure based on the GGNMOS unit. Background technique [0002] In a semiconductor chip, the most popular electrostatic discharge (Electro-Static Discharge, ESD) protection structure is usually a gate grounded GGNMOS (Gate Ground NMOS, gate grounded NMOS) structure. When ESD occurs, the parasitic triode of the ESD protection device GGNMOS will be triggered to conduct, and a breakdown (Snapback) phenomenon will occur to achieve the effect of leakage. The parasitic series resistance between the source (the emitter of the parasitic triode) and the grounded substrate (the base of the parasitic triode) is the key to triggering the conduction of the parasitic triode, but the common GGNMOS interdigitated structure in the prior art In the anti-static protection structure, su...

AI Technical Summary

Problems solved by technology

The parasitic series resistance between the source (the emitter of the parasitic triode) and the grounded substrate (the base of the parasitic triode) is the key to triggering the conduction of the parasitic triode, but the common GGNMOS interdigitated structure in the prior art In the anti-static protection structure, such as figure 1 As shown, the GGNMOS located in the center of the interdigitated structure is farthest from the ground line in both length and width directions, so its base parasitic series resistance is also the largest, so it is easiest to trigger the parasitic transistor to turn on the leakage

At this time, the MOS transistors on both sides are generally not turned on, and this uneven conduction will cause the current to concentrate in the channel area in the center, so this area is usually the most likely to be burned first

[0003] In addition, the current high ESD protection capability (such as 8KV) will require GGNMOS to have a large enough channel width (gate length) and turn-on uniformity to achieve the ability to release large currents. The number of GGNMOS interfingers or increasing the length of a single finger will make the unevenness of opening more obvious, and it is more likely that the middle protection tube will be burned and the protection tubes at both ends will not be opened. It is difficult to effectively improve the ESD protection capability.

[0004] Therefore, a GGNMOS-based anti-static protection structure is needed to solve the problem of low ESD protection capability caused by the uneven conduction of the existing GGNMOS protection tube

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