Wafer Edge Ring Volatilization for Plasma Byproduct Control
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Solution Overview
Problem
Existing plasma etching processes in semiconductor fabrication lead to byproduct material accumulation on chamber surfaces, causing adverse conditions like electrical arcing and particle contamination, which current methods fail to prevent or manage effectively during the process.
Innovation Solution
A method and system involving a wafer support structure with an edge ring structure and a byproduct volatizing gas supply to control byproduct material accumulation in a lower peripheral open region, using gases like oxygen, carbon dioxide, and carbon monoxide to volatilize and remove byproducts during the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching process is performed to remove material from wafer, then material removal is achieved, but byproduct material accumulates on chamber surfaces causing electrical arcing and particle contamination
Solution Approach 1:
A byproduct volatizing gas (oxygen, carbon dioxide, or carbon monoxide) is introduced as an intermediary substance that reacts with accumulated byproduct materials on chamber surfaces, converting them into volatile compounds that can be removed by vacuum pumping, thereby preventing electrical arcing and particle contamination while maintaining the plasma etching process
Solution Approach 2:
The chemical environment in the lower peripheral open region is changed by introducing volatizing gases, which alter the reactivity of byproduct materials on chamber surfaces, transforming them from non-volatile deposits into volatile species that can be easily removed, thus resolving the harmful accumulation problem
2Productivity
If plasma etching continues for longer duration to complete fabrication, then productivity increases, but byproduct accumulation worsens causing process interruption
Solution Approach 1:
The volatizing gas is supplied continuously or periodically during the plasma etching process to maintain continuous removal of byproduct materials, preventing accumulation that would otherwise force process interruption, thereby enabling longer uninterrupted fabrication cycles
Solution Approach 2:
The system uses the plasma process itself to generate reactive species that, in the presence of volatizing gas, automatically clean byproduct deposits on chamber surfaces during the etching process, eliminating the need for separate cleaning steps and maintaining process continuity
3Device complexity
If byproduct material is allowed to accumulate on chamber surfaces, then no additional cleaning resources are needed, but electrical arcing and particle contamination occur
Solution Approach 1:
A volatizing gas is introduced as a simple intermediary that chemically reacts with byproduct deposits to make them volatile, enabling removal through the existing vacuum system without adding complex mechanical cleaning mechanisms, thus preventing electrical arcing while maintaining system simplicity
Solution Approach 2:
The patent replaces potential mechanical cleaning systems with a chemical approach using volatizing gases, where chemical reactions convert solid/liquid byproduct deposits into gaseous species that are removed by vacuum pumping, eliminating the need for complex mechanical cleaning hardware
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
Prevents electrical arcing and particle contamination by managing byproduct accumulation, enabling longer duration plasma-based fabrication processes without interrupting the process or harming the wafer.
Implementation Method 1
supplying a byproduct volatizing gas to the lower peripheral open region to control the accumulation of the byproduct material within the lower peripheral open region during generation of the plasma
Implementation Method 2
The plasma interacts with at least one material on the semiconductor wafer so as to remove the at least one material
Data Source
AI summary
A wafer is supported on a wafer support structure such that a lower peripheral open region exists between a peripheral portion of a bottom surface of the wafer and an edge ring structure. The edge ring structure is configured to circumscribe both the wafer support structure and the wafer. A plasma is generated above a top surface of the wafer. The plasma causes accumulation of byproduct material within the lower peripheral open region. A byproduct volatizing gas is supplied to the lower peripheral open region to control the accumulation of the byproduct material within the lower peripheral open region during generation of the plasma. Use of the byproduct volatizing gas to control the accumulation of the byproduct material within the lower peripheral open region serves to prevent electrical arcing and particle contamination.