Shield gate trench MOSFET manufacturing method

Abstract

The invention relates to a shield gate trench MOSFET manufacturing method, which comprises the following steps: growing a shield gate oxide layer on the side wall of a trench of an epitaxial layer, then conducting filling with shield gate polycrystalline silicon, and etching back the shield gate polycrystalline silicon to a first target depth; depositing a silicon nitride layer with a target thickness T to form a dielectric isolation layer for isolating the shield gate polycrystalline silicon and the device gate, and etching the silicon nitride layer back to the surface of the epitaxial layer; etching the shield gate oxide layer to a second target depth, and etching the silicon nitride layer to a first target thickness K, so as to enable the upper surface of the silicon nitride layer to extend out of the surface of the shield gate oxide layer; and growing a gate oxide layer, depositing gate polycrystalline silicon, and etching the gate polycrystalline silicon to a third target depth to form the shield gate trench MOSFET. The shield gate trench MOSFET and the manufacturing method thereof have the advantages of stable structure, high production efficiency, low cost and the like.

Description

technical field [0001] The present application relates to the field of manufacturing shielded gate trench MOSFETs, in particular to a method for manufacturing shielded gate trench MOSFETs. Background technique [0002] Shielded gate trench MOSFET is currently the most advanced power MOSFET device technology, which has the advantages of lower on-resistance and faster switching speed than traditional trench MOSFET. In system applications, it has lower conduction loss and lower switching loss, and the system has higher conversion and transmission efficiency. figure 1 It is a schematic diagram of the shielded gate trench MOSFET cell structure; in order to obtain the above advantages, such as figure 1 As shown, the shielded gate trench MOSFET introduces a shielded gate structure, and the shielded gate polysilicon 110 is isolated from the gate of the device through an insulating dielectric layer. The process of isolating the shielded gate polysilicon 110 from the device gate is ...

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Problems solved by technology

[0009] The purpose of this application is to overcome the deficiencies of the prior art and provide a method for manufacturing a shielded gate trench MOSFET, which can solve many defects in the existing shielded gate trench MOSFET isolation technology

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