Forming method of shallow groove isolation structure

Abstract

A method for forming a shallow trench isolation structure comprises steps of providing a semiconductor substrate equipped with a pad oxide layer and a corrosion barrier layer sequentially, wherein the corrosion barrier layer is provided with an opening which penetrates through the corrosion barrier layer and is exposed to the pad oxide layer, utilizing the corrosion barrier layer as a mask, etching the pad oxide layer and the semiconductor substrate along the opening to form a shallow trench, wherein the lateral wall of the shallow trench is provided with polymer, leading into gas which is reacted with polymer, removing residual polymer, filling an insulating oxide layer in the shallow trench, removing the corrosion barrier layer and the pad oxide layer, and forming the shallow trench isolation structure. The invention leads the gas which is reacted with the polymer, removes the residual polymer, does not affect the lateral wall of the shallow trench, and enables the shallow trench isolation structure formed finally to be complete.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for forming a shallow trench isolation structure. Background technique [0002] As the size of integrated circuits decreases, the devices that make up the circuits must be placed more densely to fit the limited space available on the chip. Since current research is devoted to increasing the density of active devices per unit area of ​​a semiconductor substrate, effective insulating isolation between circuits becomes more important. The methods for forming isolation regions in the prior art mainly include local oxidation isolation (LOCOS) process or shallow trench isolation (STI) process. The LOCOS process is to deposit a layer of silicon nitride on the surface of the wafer, and then perform etching to oxidize and grow silicon oxide in part of the recessed area, and the active device is generated in the area determined by the silicon nitride. For isolation techno...

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Problems solved by technology

[0009] In the prior art, during the formation of shallow trenches, due to the reaction between etching gas and silicon in the semiconductor substrate, polymers are produced on the sidewalls of the shallow trenches, which affects the isolation performance of the shallow trench isolation structure, thereby affecting the performance of the semiconductor device. performance

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