Method for etching semiconductor device by using high-purity electronic-grade hexafluorobutadiene

Abstract

The invention relates to the field of semiconductor devices, and discloses a method for etching a semiconductor device by using high-purity electronic-grade hexafluorobutadiene. The method comprises the following steps: grafting a polyacrylamide cross-linked network onto the pore wall of C-type silica gel to prepare water absorption response type silica gel; sequentially carrying out water absorption response type silica gel adsorption impurity removal, light component rectification and heavy component rectification on hexafluorobutadiene raw material gas to obtain high-purity electronic-grade hexafluorobutadiene; and forming an insulating layer on a semiconductor substrate, forming a patterned mask layer on the insulating layer, and after etching gas containing high-purity electronic-grade hexafluorobutadiene forms plasma, using the plasma to perform dry etching on the insulating layer. The water absorption capacity response type silica gel adopted by the invention can utilize the water absorption swelling characteristic of a cross-linked network in holes, so that the water absorption rate at the initial stage and the later stage of adsorption is relatively high, the water content in high-purity electronic-grade hexafluorobutadiene is reduced, and the influence of the high-purity electronic-grade hexafluorobutadiene on the performance of a semiconductor device after the high-purity electronic-grade hexafluorobutadiene is etched is prevented.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to an etching method for semiconductor devices using high-purity electronic-grade hexafluorobutadiene. Background technique [0002] The manufacture of semiconductor integrated circuits requires extremely fine-scale patterns on wafers. The most important way to form these patterns is to use etching technology to transfer the photoresist patterns (including lines, planes, holes, etc.) produced by lithography technology onto the film accurately by means of wet etching or dry etching. , to define the complex structure needed for the entire integrated circuit. Wet etching is an isotropic etching reaction under the action of a strong acid, and it is easy to etch the part covered by the mask; in contrast, dry etching using corrosive gases or plasma ions uses gas molecules or ion radicals produced by them , to perform physical impact sputtering and chemical reaction on the material o...

AI Technical Summary

Problems solved by technology

In the prior art, the methods of adsorption, impurity removal and rectification are often used to purify the raw material gas of hexafluorobutadiene. Due to the low moisture content in the raw material gas of hexafluorobutadiene, compared with silica gel and adsorption resin In terms of molecular sieves, molecular sieves have good water removal performance at low humidity. Therefore, molecular sieves are usually used to adsorb and remove impurities from raw material gas (such as patent CN107032949B), but at the same time, there are acid centers in molecular sieves, which will cause hexafluorobutadiene Rearrangement produces its isomer hexafluorobutyne, which affects the purity and yield of hexafluorobutadiene gas; and although there is no acid center in silica gel and adsorption resin, its water removal performance at low humidity is relatively low. Poor, using it as an adsorbent also cannot obtain high-purity electronic grade hexafluorobutadiene gas

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