Reactive Ion Etching in the Gaseous Electronics Conference RF Reference Cell.

Area of Science:

• Materials Science and Engineering
• Plasma Science and Technology
• Semiconductor Manufacturing

Background:

• Reactive ion etching (RIE) is a critical process in semiconductor fabrication.
• Standardized reference cells, like the Gaseous Electronics Conference (GEC) reference cell, are essential for reproducible plasma process research.
• Investigating the performance of RIE in a GEC cell provides valuable data for process development and comparison.

Purpose of the Study:

• To evaluate the GEC reference cell as a reactive ion etcher for silicon-based materials.
• To characterize etch performance using fluorine and chlorine-based plasma chemistries.
• To compare etch results from the GEC cell with those from a commercial etching system.

Main Methods:

• Silicon wafers with polysilicon and silicon dioxide layers, patterned with photoresist, were etched.
• Fluorine and chlorine chemistries were employed in the GEC reference cell.
• Techniques including Scanning Electron Microscopy (SEM), profilometry, optical emission spectroscopy, and bias voltage measurements were utilized for analysis.

Main Results:

• Etch rates varied from 5-177 nm/min for fluorine chemistries and 25-90 nm/min for chlorine chemistries.
• Consistent etch rates and patterns were achieved across different GEC cell discharges and conditions.
• GEC cell etch rates and relative fluorine concentrations showed similarity to a commercial etcher, though generally lower.

Conclusions:

• The GEC reference cell demonstrates viable performance as a reactive ion etcher for silicon wafer processing.
• The study validates the GEC cell's utility for research and development in plasma etching processes.
• Findings support the GEC cell as a reliable platform for comparative studies against commercial etching equipment.