Plasma Etching Chemistry for Silicon Films Without Tin Fluoride
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Solution Overview
Problem
Existing plasma processing methods face challenges in efficiently etching silicon-containing films while minimizing the formation of tin fluoride on metal-containing masks, which can lead to defects in semiconductor device manufacturing.
Innovation Solution
A plasma processing method involving a substrate with a silicon-containing first etching film and a metal-containing mask, where plasma is generated using a processing gas containing chlorine or bromine gases to etch the first etching film without forming tin fluoride on the mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processing methods are used to etch silicon-containing films, then etching can be performed, but tin fluoride forms on metal-containing masks causing defects
Solution Approach 1:
The patent changes the chemical composition parameters of the processing gas by selecting specific chlorine-containing gases (Cl2, CCl4, CHCl3, CCl2F2) and bromine-containing gases (Br2, BBr3) that have appropriate reactivity with silicon-containing films but do not react with tin to form tin fluoride. This parameter change resolves the contradiction by enabling effective etching while preventing harmful tin fluoride formation on the mask.
Solution Approach 2:
The patent employs a mask made of metal-containing film that is designed to be consumed or replaced. The mask material (tin-containing film) is selected and configured such that it can withstand the etching process without forming harmful compounds, and any minor degradation is acceptable since the mask can be replaced. This approach allows the use of aggressive etching conditions that would otherwise damage the mask, thereby improving etching precision without suffering from long-term mask degradation.
2Productivity
If aggressive etching conditions are used to improve etching speed, then productivity increases, but mask damage and defects increase
Solution Approach 1:
The patent optimizes the processing gas parameters by using chlorine-containing gases or bromine-containing gases that provide high etching speed through strong chemical reactivity with silicon-containing films, while simultaneously selecting gas compositions that do not cause tin fluoride formation or other harmful reactions with the mask material. This parameter optimization allows aggressive etching conditions to be used without compromising mask integrity.
Solution Approach 2:
The patent introduces a specifically designed metal-containing film mask that acts as an intermediary between the plasma environment and the underlying structures. This mask layer is engineered to be resistant to the specific plasma chemistry used, serving as a protective barrier that allows aggressive etching conditions to be applied to the silicon-containing film without damaging critical underlying structures or forming harmful byproducts.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively reduces defects in the etching process by preventing the formation of tin fluoride, thereby improving the critical dimension and line width roughness of the etched films.
Implementation Method 1
generating plasma in the chamber with a processing gas including one or both of a chlorine-containing gas and a bromine-containing gas to etch the first etching film
Implementation Method 2
generating plasma in the chamber with a processing gas including one or both of a chlorine-containing gas and a bromine-containing gas to etch the first etching film
Data Source
AI summary
A plasma processing method according to the present disclosure includes a preparing a substrate having a first etching film and a mask on the first etching film, the mask including a metal-containing film; and generating plasma in a chamber with a processing gas including one or both of a chlorine-containing gas and a bromine-containing gas to etch the first etching film.