Manufacturing method of semiconductor device

Abstract

The invention provides a manufacturing method of a semiconductor device. The manufacturing method mainly comprises the following steps: forming an oxide layer and a source polycrystalline silicon layer of which the upper surface is higher than the surface of a semiconductor substrate in a deep trench of the semiconductor substrate; forming a photoresist layer to distinguish a terminal region and aprimitive cell region; etching the source polycrystalline silicon layer at the primitive cell region; etching the oxide layer at the primitive cell region to form a gate trench; removing the photoresist; and forming a gate oxide layer and an isolation dielectric layer in the gate trench, and then forming a gate polysilicon layer. The top of the source polysilicon layer filled in the deep trench is higher than the surface of the semiconductor substrate. The height difference between the top of the source polycrystalline silicon layer and the top of the oxide layer is reduced, so that the problem of incomplete etching of the gate polycrystalline silicon in the transition region of the gate polycrystalline silicon layer and the source polycrystalline silicon layer during subsequent back etching of the gate polycrystalline silicon layer is avoided, and the problem of saturated gate current failure caused by short circuit of the gate and the shielding gate is solved.

Description

technical field [0001] The invention relates to the technical field of manufacturing semiconductor integrated circuits, in particular to a method for manufacturing a semiconductor device. Background technique [0002] Shielded gate trench devices (SGT, shielded gate power devices) in the shielded gate photomask reduction process, polysilicon residues will appear in the transition region between the gate polysilicon and the shielded gate polysilicon, eventually causing the gate and shield The gate is shorted, causing the saturated gate current (IGSS) to fail. [0003] Such as Figure 1A to Figure 1N Shown is a schematic diagram of the device structure in each step of the manufacturing method of the existing shielded gate trench power device. In the prior art, the manufacturing process of shielded gate power devices includes the following steps: [0004] Step one, such as Figure 1A As shown, a semiconductor substrate such as a silicon substrate 101 is provided; a hard mask...

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Problems solved by technology

[0017] The purpose of the present invention is to provide a method for manufacturing a semiconductor device to solve the pr

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