Trench gate MOSFET power semiconductor device and polycrystalline silicon filling method and manufacturing method thereof

Abstract

The invention discloses a trench gate MOSFET power semiconductor device and a polysilicon filling method and a manufacturing method thereof. The filling method comprises the following steps: forming agroove in an epitaxial layer on a semiconductor substrate; forming an insulating layer on the surface of the epitaxial layer and in the groove, wherein the insulating layer surrounds the groove to form a cavity; forming an i-th polycrystalline silicon layer on the surface of the epitaxial layer and in the cavity; performing back etching on the i-th polycrystalline silicon layer; forming an (i + 1)-th polycrystalline silicon layer on the exposed cavity or gap in the i-th polycrystalline silicon layer; and removing the (i + 1)-th polycrystalline silicon layer above the surface of the epitaxiallayer and the insulating layer above the surface of the epitaxial layer, wherein the i-th polycrystalline silicon layer to the (i + 1)-th polycrystalline silicon layer form a shielding conductor. According to the invention, the plurality of polycrystalline silicon layers are formed in the trench to eliminate holes or gaps, thereby improving the yield and reliability of the power semiconductor device and prolonging the service life of the power semiconductor device.

Description

technical field [0001] The invention relates to the technical field of manufacturing power semiconductor devices, in particular to a trench gate MOSFET power semiconductor device with high withstand voltage and a polysilicon filling method and manufacturing method thereof. Background technique [0002] A schematic structural diagram of a power semiconductor device in the prior art is shown in figure 1 shown. As an example, the power semiconductor device is a trench gate MOSFET power semiconductor device. [0003] Such as figure 1 As shown, a trench gate MOSFET power semiconductor device 100 includes a plurality of trenches 120 in an epitaxial layer 102 on a semiconductor substrate 101 . [0004] Figures 2a to 2h show separately figure 1 Cross-sectional views at different stages of the fabrication method of the shown power semiconductor device. [0005] Such as Figure 2a As shown, a trench 120 with a depth h1 is formed in the epitaxial layer 102 on the semiconductor ...

AI Technical Summary

Problems solved by technology

[0017] Void or gap defects in the shielding conductor lead to failures such as breakdown or short circuit of power semiconductor devices, which adversely affects the yield, reliability and life of power semiconductor devices

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