Manufacturing method of trench IGBT

Abstract

The invention provides a manufacturing method of a trench IGBT. The method comprises the following steps: providing a substrate and dividing into an active region and a terminal structure region; opening a window of a protection ring in the terminal structure region; through an ion implantation and diffusion technology, forming the device protection ring in the substrate; forming field oxide on a surface of the substrate and completing an active region definition; forming a groove hard mask layer and a photoresist layer on the surfaces of the substrate and the field oxide, and imaging the photoresist layer; etching the groove hard mask layer and exposing the substrate; depositing a sidewall protection layer on the surface of the substrate and performing etchback, forming protection side walls on sidewalls of two sides of the groove hard mask layer and growing a thermal oxide layer on the surface of the substrate; taking the groove hard mask layer and the protection side walls as the hard mask so as to successively etch the thermal oxide layer and the substrate and forming a groove in the substrate, wherein the thermal oxide layer which is on a top of the groove extends between the protection side walls and the substrate so as to form a beak. According to the invention, generation of a closed angle of the groove top can be avoided. Grid leakage failure and a reliability problem caused by the closed angle can be prevented.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing, in particular, the invention relates to a method for manufacturing a trench insulated gate bipolar transistor. 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. This 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]...

AI Technical Summary

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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