Manufacturing method of semiconductor device of discrete field oxide structure

Abstract

The invention discloses a manufacturing method of a semiconductor device of a discrete field oxide structure. The method comprises steps: a buffer oxide layer grows on the surface of a wafer; a silicon nitride layer is formed on the buffer oxide layer through deposition; a field region is defined through photoetching and etching is carried out, and silicon nitride in the field region is removed; ion implantation is carried out on the field region; a field oxide layer grows; the silicon nitride layer is removed; wet dip is carried out on the wafer, and the buffer oxide layer and partial field oxide layer are removed; the buffer oxide layer grows again on the surface of the wafer and the silicon nitride layer is formed on the newly-grown buffer oxide layer through deposition; a drift region is defined through photoetching and etching is carried out, and silicon nitride in the drift region is removed; ion implantation is carried out on the drift region; and a drift region oxide layer grows. According to the method, the silicon nitride layer is removed after growing of the field oxide layer is finished, the length of a field oxide beak can be optimized through adjusting the amount of wet dip and the problem that the field oxide beak is excessively long can be solved.

Description

technical field [0001] The invention relates to the manufacture of the isolation region between components of the semiconductor device, in particular to a manufacturing method of the semiconductor device with a discrete field oxygen structure. Background technique [0002] In the design of modern integrated circuits, high-voltage lateral diffusion drift region MOS transistors (LDMOS) devices are widely used. The withstand voltage of LDMOS is realized by the principle of reducing the surface electric field (RESURF) by using the drift region of the drain end of the MOS transistor. This drift region is formed by ion implantation followed by diffusion through high temperature thermal processes. The drift region structure usually includes a thermal oxide layer with a certain thickness. Polysilicon is placed on the thermal oxide layer to change the potential distribution on the upper surface of the drift region to completely deplete the drift region and achieve the ultimate withst...

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Problems solved by technology

[0004] Based on this, it is necessary to provide a semiconductor device with a discrete field oxygen structure that can optimize the length of the bird's beak of the field oxygen method to solve the problem that the bird's beak area is too long in the traditional stacked field oxygen method.

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