Effect of C2H2F4/CF4O with low global warming potentials on SiNx etching as a CHF3 replacement
Kyung Lim Kim1,2, Jong Woo Hong3, Young Woo Jeon4
1Department of Semiconductor and Display Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Scientific Reports
|November 18, 2025
Summary
New eco-friendly gases like C2H2F4 and CF4O significantly improve silicon nitride (SiNx) etching for semiconductor manufacturing. These alternatives offer higher etch rates and selectivity while reducing greenhouse gas emissions compared to traditional CHF3.
Area of Science:
- Semiconductor Manufacturing
- Materials Science
- Environmental Chemistry
Background:
- Double patterning processes in semiconductor manufacturing require silicon nitride (SiNx) etching with high etch rate and selectivity over silicon dioxide (SiOx).
- Traditional etching gases like CHF3/CF4 have limitations including low selectivity and high global warming potential (GWP).
Purpose of the Study:
- Investigate alternative gases to CHF3 for SiNx etching in double patterning.
- Evaluate the impact of C2H2F4 and CF4O on etch characteristics and environmental footprint.
Main Methods:
- Experimental investigation of SiNx etching using C2H2F4 and C2H2F4 + CF4O mixtures.
- Analysis of etch rate, etch selectivity, trenching, critical dimension (CD) changes, and polymer formation.
- Measurement of greenhouse gas emissions (MMTCE) for comparison with CHF3.
Main Results:
- C2H2F4 improved etch rate and selectivity but caused trenching and CD increase.
- Adding CF4O to C2H2F4 further enhanced etch rate and selectivity, eliminating trenching.
- Alternative gases demonstrated significantly reduced greenhouse gas emissions compared to CHF3.
Conclusions:
- C2H2F4 + CF4O offers a superior eco-friendly alternative for SiNx etching, balancing performance and environmental impact.
- These advanced etching processes are suitable for next-generation semiconductor devices like FinFET and 3D NAND.
- The study highlights the development of sustainable etching solutions for the semiconductor industry.
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