Plasma Chamber Gas-Line Purging for Wafer CD Uniformity
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Solution Overview
Problem
Existing semiconductor processing technologies face challenges in maintaining wafer-to-wafer uniformity due to residual oxygen in the gas lines after cleaning the plasma processing chamber, which affects the critical dimension (CD) of etched layers and increases semiconductor device defects.
Innovation Solution
Implementing a method that includes purging the gas lines with inert gases such as nitrogen, helium, or argon after each cleaning cycle to remove residual oxygen, using a bleed line connected to the turbopump to prevent oxygen from leaking back into the plasma processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the plasma processing chamber is cleaned between processing cycles, then residues are removed from the chamber, but residual oxygen remains in the gas lines and leaks back into the chamber affecting CD uniformity
Solution Approach 1:
The patent extracts and removes residual oxygen from the gas lines using a purge system that flows inert gas through the gas lines to displacement the oxygen before processing begins, preventing oxygen leakage into the plasma processing chamber that would otherwise affect CD uniformity
Solution Approach 2:
The patent introduces inert gas (nitrogen, helium, or argon) as an intermediary substance that flows through the gas lines to push out residual oxygen, acting as a mediator between the cleaning process and the plasma processing to maintain CD uniformity without requiring complete system disassembly
2Manufacturing precision
If gas lines are purged with inert gas to remove residual oxygen, then CD uniformity improves, but processing time and system complexity increase
Solution Approach 1:
The patent performs preliminary purging of the gas lines with inert gas before each plasma processing cycle to remove residual oxygen, ensuring CD uniformity is maintained from the start of processing without requiring extended processing time during the actual fabrication cycle
Solution Approach 2:
The patent designs the purge system to serve multiple functions: it removes residual oxygen from gas lines, prevents oxygen leakage into the chamber, and can be integrated with existing vacuum and gas delivery systems, reducing the need for separate dedicated purification equipment
3Productivity
If residual oxygen is not removed from gas lines, then processing speed is maintained, but semiconductor device defects increase
Solution Approach 1:
The patent rapidly purges the gas lines with inert gas in a brief preliminary step before processing, quickly displacing residual oxygen through high-flow inert gas that rushes through the lines to clear contaminants without adding significant time to the overall production cycle
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
This approach significantly improves CD uniformity by at least four times, reducing semiconductor device defects and maintaining consistent processing results across multiple wafers.
Implementation Method 1
purging the at least one gas line with an inert gas including at least one of nitrogen (N2), helium (He), and argon (Ar)
Implementation Method 2
A first turbopump with an inlet is in fluid connection with the plasma processing chamber and an exhaust
Data Source
AI summary
An apparatus for providing plasma processing is provided. A plasma processing chamber is provided. A first turbopump with an inlet is in fluid connection with the plasma processing chamber and an exhaust. A gas source provides gas to the plasma processing chamber. At least one gas line is in fluid connection between the gas source and the plasma processing chamber. At least one bleed line is in fluid connection with the at least one gas line. At least one gas line valve is on the at least one gas line located between, where the at least one bleed line is connected to the at least one gas line and the plasma processing chamber. At least one bypass valve is on the at least one bleed line.