Method for manufacturing trench power device structure

Abstract

The invention provides a method for manufacturing a trench power device structure. The method comprises the following steps of: providing a substrate, and dividing the substrate into an active area and a terminal structure area; forming a protection ring in the substrate by using an ion injection and diffusion process; forming a field oxide on the surface of the substrate, and defining the active area; forming a trench hard mask layer and a photoresist layer on the surfaces of the substrate and the field oxide, and performing graphical operation on the photoresist layer, wherein the position of a trench is partially overlapped with the edge of the field oxide; sequentially etching the trench hard mask layer and the field oxide, and exposing the substrate; by taking the trench hard mask layer as a mask, etching the substrate to form the trench, and then removing the trench hard mask layer; growing a gate oxidation layer on the inner wall of the trench, wherein the gate oxidation layer extends from the edge of the top of the trench into the lower part of the field oxide to form a beak; and performing subsequent semiconductor process to finish the manufacturing process of the trench power device structure. The method has the advantages that: the process steps are not added in the original process; formation of a protrusion at the top of the trench is avoided; and the problems of gate electric leakage failure and low reliability caused by the protrusion at the top of the trench are solved.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing, and in particular, the invention relates to a method for manufacturing a trench power device structure. Background technique [0002] Power devices including MOSFETs, IGBTs and their modules have been widely used in automotive electronics, switching power supplies, and industrial control, and are currently a hot research field. With the development of integrated circuit microfabrication technology, trench (Trench) structure power devices have become one of the most popular power switching devices at present. It uses a gate oxide layer grown on the sidewall of the trench and filled with polysilicon to form a gate. The trench gate structure greatly improves the utilization efficiency of the planar area of ​​the device, so that a larger unit channel width of the device can be obtained per unit area, thereby obtaining a greater current conduction capability. [0003] The man...

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Problems solved by technology

There are related methods of adding multiple times of thermal oxidation or additional high-density plasma (HDP) etching after trench etching to obtain trenches with slope tops, but this is not only complicated in process, but also easy to cause gate oxide bands. to defect

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