Method for improving polymer in thick aluminum etching process

Abstract

The invention provides a method for improving a polymer in a thick aluminum etching process. The method comprises the following steps of: providing a silicon substrate, and forming an oxide layer on the silicon substrate; forming a composite layer of titanium nitride and titanium on the oxide layer; forming an aluminum layer on the composite layer; forming a photoresist layer on the aluminum layer; exposing and developing the photoresist to form a photoresist pattern; etching the aluminum layer according to the photoresist pattern to form a groove; and adopting plasma etching for etching the aluminum layer, and introducing helium into an etching cavity to serve as etching gas. In the manufacturing process of the power MOS device, the equivalent voltage of the surface of an electrostatic chuck and the pressure of an etching cavity are increased in the etching step of an aluminum layer, and helium is introduced as an alternative gas to bombard more photoresist to the surface of the side wall of the aluminum layer; and the polymer components can be converted into a polymer mainly comprising photoresist, so that the polymer is easy to remove, plasma dissociation can be promoted, and an aluminum-containing polymer is not easy to form.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for improving polymer in thick aluminum etching process. Background technique [0002] In the manufacturing process of power MOS devices, the photoresist layer and the aluminum layer on the aluminum layer in the MOS structure are relatively thick, with a thickness of about 4 microns. After etching the aluminum layer, it was found that the polymer on the aluminum sidewall remained seriously. Cannot be completely removed after passing through the chamber. [0003] Therefore, a new method needs to be proposed to solve the above problems. Contents of the invention [0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for improving the polymer in the thick aluminum etching process, which is used to solve the problem that the aluminum sidewall cannot be completely removed during the producti...

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Problems solved by technology

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for improving the polymer in the thick aluminum etching process, which is used to solve the problem that the aluminum sidewall cannot be completely removed during the production process of the power MOS device in the prior art. polymer problem

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