Plasma Etching Using HFIP and Argon Gas
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Solution Overview
Problem
Conventional perfluorocarbon (PFC) gases used in plasma etching have high global warming potential (GWP) and hinder the formation of high aspect ratio structures due to excessive fluorocarbon thin film formation, which interferes with etching processes in semiconductor manufacturing.
Innovation Solution
A plasma etching method using a combination of hexafluoroisopropanol (HFIP) and argon gases, supplied at specific flow rate ratios, to plasma-etch silicon oxide and nitride targets, reducing GWP and enhancing etching characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If perfluorocarbon (PFC) gas is used for plasma etching, then etching process can be performed, but global warming potential increases significantly
Solution Approach 1:
The patent changes the chemical composition parameter of the etching gas from conventional PFC gas (CF4, C2F6, C3F8, C4F8) to hexafluoroisopropanol (HFIP) gas. This parameter change reduces the global warming potential from 6500 times higher than CO2 to a much lower value, while maintaining the etching capability through plasma activation of the HFIP gas
Solution Approach 2:
The patent employs HFIP gas which has a shorter atmospheric lifetime compared to conventional PFC gases. This allows the etching process to achieve its function while the gas decomposes more quickly in the atmosphere, reducing long-term environmental accumulation and harm
2Ease of manufacture
If perfluorocarbon (PFC) gas is used for plasma etching, then etching can proceed, but fluorocarbon thin film formation interferes with etching and prevents high aspect ratio structure formation
Solution Approach 1:
The patent changes the gas composition from PFC to HFIP, which alters the chemical behavior during etching. HFIP produces fewer fluorocarbon thin films compared to PFC gases, reducing the interference with ion diffusion and enabling the formation of high aspect ratio structures without etching stop phenomena
Solution Approach 2:
The patent extracts and removes the harmful fluorocarbon thin film formation side effect by using HFIP gas instead of PFC gas. This eliminates the excessive film deposition that blocks etching pathways and prevents high aspect ratio structure formation, while retaining the beneficial etching functionality
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 achieves etching characteristics up to four times higher than conventional PFC gas methods while reducing greenhouse gas emissions and enabling the formation of high aspect ratio structures, making it an environmentally friendly alternative for semiconductor and display manufacturing.
Implementation Method 1
supplying both hexafluoroisopropanol (HFIP) gas and argon (Ar) gas to a plasma chamber receiving an etching target therein, thereby to plasma-etch the etching target
Data Source
AI summary
Provided is a plasma etching method comprising supplying both hexafluoroisopropanol (HFIP) gas and argon (Ar) gas to a plasma chamber receiving an etching target therein, thereby to plasma-etch the etching target.