Manufacturing method of trench-gate superjunction device

Abstract

The invention discloses a manufacturing method of a trench-gate superjunction device. The manufacturing method comprises the steps of 1, forming a trench gate, wherein the step 1 comprises the steps of 11, forming a gate groove in a first epitaxial layer in which a superjunction structure is not formed; 12, forming a gate oxide layer, and rounding a bottom angle and a top angle of the gate grooveby a thermal oxidization process of the gate oxide layer; and 13, forming a poly-silicon gate; and 2, forming the superjunction structure, wherein the step 2 comprises the steps of 21, forming a superjunction post groove; and 22, filling a second epitaxial layer in the superjunction post groove to form a second conductive type of post of the superjunction structure, wherein the first conductive type of post of the superjunction structure comprises the first epitaxial layer between the superjunction grooves. By the manufacturing method, the electric leakage of the device can be reduced, the reliability of the device is improved, and meanwhile, the specific conduction resistance of the device also can be reduced.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor integrated circuit, in particular to a method for manufacturing a trench gate superjunction (superjunction) device. Background technique [0002] The super-junction structure is composed of alternately arranged N-type columns and P-type columns. The manufacturing process of the super-junction device in the prior art includes multiple epitaxial manufacturing processes and trench-filling manufacturing processes. The multiple epitaxial manufacturing processes pass Multiple photolithography and ion implantation, followed by annealing to form alternately arranged P-N columns, that is, P-type columns and N-type columns; taking super-junction devices as NMOSFETs as an example, the trench-filling manufacturing process is in the N-type epitaxial layer Etch the groove, and then fill the groove with a P-type epitaxial layer, such as a P-type silicon epitaxial layer, that is, P-type epitaxial sili...

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Problems solved by technology

In this way, the thermal process during the formation of the trench gate will affect the diffusion between the P-type column and the N-type column, especially when forming a gate oxide layer or forming a sacrificial oxide layer requires a very high temperature. It will intensify the diffusion of P-type impurities to N-type pillars, resulting in an increase in the specific on-resistance of the device

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