Plasma Etching Gas Chemistry for Selective Silicon Film Patterning
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Solution Overview
Problem
Existing plasma etching methods face challenges in achieving high selectivity of silicon-containing films to masks during the etching process.
Innovation Solution
An etching method utilizing a process gas containing hydrogen fluoride and a phosphorus-containing gas, along with optional halogen-, carbon-, and oxygen-containing gases, to enhance the selectivity of silicon-containing films to masks by using chemical species generated in plasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional process gases are used for plasma etching, then the etching process can proceed, but the selectivity of silicon-containing films to masks is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the process gas by introducing hydrogen fluoride gas and phosphorus-containing gas. This chemical parameter change modifies the plasma chemistry to generate etching species that selectively react with silicon-containing films while being less reactive with mask materials, thereby improving selectivity and pattern transfer accuracy
Solution Approach 2:
The patent uses a composite process gas mixture containing hydrogen fluoride gas, phosphorus-containing gas, and optionally halogen-, carbon-, and oxygen-containing gases. This composite gas formulation creates a synergistic effect where different gas components contribute different reactive species that work together to achieve high selectivity etching of silicon-containing films while protecting the mask
2Productivity
If conventional process gases are used, then the etching can be performed, but feature failures such as bowing and mask clogging occur
Solution Approach 1:
The patent modifies the process gas composition parameters to include hydrogen fluoride gas and phosphorus-containing gas, which changes the etching chemistry to reduce unwanted side effects. This parameter change suppresses feature bowing and mask clogging while maintaining high etching efficiency, enabling precise pattern formation
Solution Approach 2:
The phosphorus-containing gas acts as an intermediary that modifies the etching process by introducing phosphorus-based chemical species. These intermediate species facilitate selective etching of silicon-containing films while reducing direct damage to mask structures and preventing feature bowing, thereby improving feature shape accuracy
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
Improves the selectivity of silicon-containing films to masks during plasma etching, allowing for precise pattern transfer and reducing feature failures such as bowing and mask clogging.
Implementation Method 1
etching the silicon-containing film with a chemical species in plasma generated from a process gas in the chamber
Implementation Method 2
etching the silicon-containing film with a chemical species in plasma generated from a process gas containing a hydrogen fluoride gas and a phosphorus-containing gas
Data Source
AI summary
An etching method includes (a) providing a substrate in a chamber in a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method further includes (b) etching the silicon-containing film with a chemical species in plasma generated from a process gas in the chamber. The process gas contains a hydrogen fluoride gas and a phosphorus-containing gas.