Plasma Etching Selectivity via Hydrogen Fluoride Gas Concentration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma etching methods face challenges in achieving selectivity when etching silicon-containing films compared to masks, particularly due to the lack of effective control over the etching process, leading to inefficient processing and potential damage to the mask.
Innovation Solution
A substrate processing method involving a plasma processing apparatus that generates plasma from a first process gas with a hydrogen fluoride gas flow rate of at least 25 vol % of non-inert components, specifically designed to improve the selectivity of etching silicon-containing films over masks by controlling the etching process with precise gas flow rates and compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching methods are used, then the etching process can be performed, but the selectivity between silicon-containing film and mask is insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the hydrogen fluoride gas flow rate to be at least 25 vol % of non-inert components in the first process gas. This specific parameter adjustment enables high etching selectivity (mask etching rate suppression of 90% or more) while maintaining controllable processing conditions, directly resolving the contradiction between achieving high selectivity and maintaining process ease
2Productivity
If etching rate for silicon-containing film is increased, then productivity improves, but mask damage increases
Solution Approach 1:
The patent applies local quality by creating different chemical environments for different regions: the silicon-containing film region experiences high reactivity plasma conditions that enable fast etching, while the mask region experiences suppressed reactivity due to the specific hydrogen fluoride gas concentration (at least 25 vol % of non-inert components). This results in high etching rate for the film while minimizing mask damage
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 method significantly enhances the selectivity of etching silicon-containing films over masks, ensuring higher etching rates for films while minimizing mask damage, as demonstrated by experimental results showing improved etching selectivity with optimal hydrogen fluoride gas flow rates.
Implementation Method 1
generating plasma from a first process gas containing a hydrogen fluoride gas in the chamber
Implementation Method 2
etching the silicon-containing film with a chemical species contained in the plasma
Data Source
AI summary
A technique improves selectivity in etching of a silicon-containing film over etching of a mask in plasma etching. A substrate processing method includes placing a substrate in a chamber in a plasma processing apparatus. The substrate includes a silicon-containing film and a mask on the silicon-containing film. The substrate processing method further includes generating plasma from a first process gas containing a hydrogen fluoride gas in the chamber. The generating plasma includes etching the silicon-containing film with a chemical species contained in the plasma. A flow rate of the hydrogen fluoride gas is at least 25 vol % of a total flow rate of the non-inert components of the first process gas.