Edge Ring Conductance Features for Wafer Notch Gas Flow Uniformity
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Solution Overview
Problem
Existing edge rings in semiconductor processing can cause non-uniformities due to trapped process gases and interactions with wafer features like notches or flats, leading to uneven gas flow and deposition/etching issues.
Innovation Solution
The edge ring is designed with flow conductance features such as raised and recessed sections, overhangs, and cut-out sections to adjust and equalize the gas flow between the edge ring and the wafer, aligning with wafer features to mitigate non-uniformities by modifying the inner edge and underside surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a standard edge ring with uniform inner bottom surface is used, then the edge ring structure is simple and easy to manufacture, but gas flow non-uniformities occur due to trapped process gases and interactions with wafer features
Solution Approach 1:
The edge ring incorporates localized flow conductance features including raised sections, recessed sections, and overhang sections at specific angular positions. These localized structural variations modify gas flow characteristics in specific regions to compensate for non-uniformities caused by wafer features such as notches or flats, thereby achieving uniform gas flow distribution across the wafer surface without requiring complete redesign of the entire edge ring structure.
2Reliability
If the edge ring inner edge is positioned close to the wafer edge for effective edge protection, then edge protection coverage is improved, but non-uniform interactions with wafer features like notches or flats cause deposition or etching non-uniformities
Solution Approach 1:
The inner edge of the edge ring is equipped with localized flow conductance features such as raised sections, recessed sections, and overhang sections positioned at specific angular sectors. These features create localized modifications in gas flow patterns that compensate for non-uniform interactions with wafer features like notches or flats, ensuring uniform deposition or etching across the wafer edge while maintaining effective edge protection coverage.
Solution Approach 2:
The flow conductance features are designed to preemptively counteract the non-uniform gas flow effects that would otherwise be caused by wafer features. By positioning raised sections, recessed sections, and overhang sections at predetermined angular positions, the edge ring pre-establishes compensatory flow patterns that neutralize the adverse effects of wafer notches or flats before they can cause deposition or etching non-uniformities.
3Object-generated harmful factors
If process gases are introduced under the edge ring to purge trapped gases, then trapped process gases can be removed, but gas flow non-uniformities may still occur due to interactions with wafer features
Solution Approach 1:
The edge ring incorporates localized flow conductance features including raised sections, recessed sections, and overhang sections that create specific gas flow pathways. These localized structures guide the purging process gas to effectively remove trapped gases from specific regions under the edge ring while simultaneously compensating for non-uniform interactions with wafer features, thereby achieving both trapped gas removal and uniform gas flow distribution.
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
These features allow for localized adjustment of gas flow, reducing non-uniformities and ensuring consistent gas distribution across the wafer, thereby improving processing uniformity and reducing the impact of wafer features on edge ring performance.
Implementation Method 1
flow conductance features such as raised and recessed sections, overhangs, and cut-out sections to adjust and equalize the gas flow between the edge ring and the wafer
Data Source
AI summary
Improved edge rings with flow conductance features are disclosed. The flow conductance features of the edge ring are features added to the edge ring that adjust the flow conductance of gas flowing in the local area of the edge ring. The flow conductance features can adjust the flow conductance to compensate for features on a semiconductor wafer, the edge ring, and in the chamber that may affect the flow of gas in the local areas. The flow conductance may be increased, reduced, or tuned depending on the desired effect.