Plasma Etching of Silicon Films With Carbon-Phosphorus Mask Protection
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Solution Overview
Problem
Existing plasma etching methods for silicon-containing films do not adequately protect the substrate during the etching process, leading to failures in the mask features.
Innovation Solution
Forming a carbon-phosphorus bond on the mask surface using a process gas containing a halogen and phosphorus component, which enhances protection during plasma etching by reducing etching in the mask's lower density regions and passivating the side wall surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plasma etching methods are used for silicon-containing films, then the etching process can be performed, but the mask features are not adequately protected leading to etching damage and failures
Solution Approach 1:
A protective film is formed on the mask surface before the plasma etching process begins. This preliminary protective layer prevents direct contact between the plasma and the mask, thereby protecting the mask features from etching damage while allowing the etching process to proceed on the silicon-containing film underneath
Solution Approach 2:
The protective film acts as an intermediary layer between the plasma and the mask. It absorbs the harmful effects of the plasma on the mask while still permitting the necessary etching reactions to occur on the silicon-containing film, thus mediating the interaction between the plasma and the mask structure
2Reliability
If the mask is protected during plasma etching, then mask integrity is maintained, but the etching rate or process efficiency may be reduced
Solution Approach 1:
The protective film is applied selectively to specific regions where mask protection is needed, rather than uniformly across the entire substrate. This localized approach ensures that mask areas receive protection while other areas maintain full etching efficiency, thus balancing protection needs with productivity requirements
Solution Approach 2:
The thickness and composition of the protective film are carefully controlled and optimized to provide adequate protection while minimizing interference with the etching process. By adjusting these parameters, the system achieves both mask protection and maintained etching efficiency
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
The carbon-phosphorus bond effectively protects the mask and substrate from etching damage, reducing failures in mask features and maintaining the integrity of the silicon-containing film.
Implementation Method 1
etching the silicon-containing film with a plasma generated from a process gas supplied to the chamber
Implementation Method 2
forming a carbon-phosphorus bond on a surface of the mask
Data Source
AI summary
A technique protects a mask in plasma etching of a silicon-containing film. An etching method includes providing a substrate in a chamber included in a plasma processing apparatus. The substrate includes a silicon-containing film and a mask. The mask contains carbon. The etching method further includes etching the silicon-containing film with a chemical species in plasma generated from a process gas in the chamber. The process gas contains a halogen and phosphorus. The etching includes forming a carbon-phosphorus bond on a surface of the mask.