Self-Adjusting Pump Liner Valves for Uniform Gas Flow
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Solution Overview
Problem
Current processing chambers face challenges in achieving uniform gas flow due to asymmetric pumping, which is sensitive to flow uniformity around the wafer, and existing solutions for optimizing pumping liner hole sizes are expensive, time-consuming, and often fail to achieve uniformity.
Innovation Solution
The introduction of self-adjusting valve assemblies within pump liners, comprising a valve housing, inner cylinder, compression element, and slidable gate, which adjust flow conductance based on pressure differentials to maintain uniform gas flow across the wafer, regardless of chamber design or fore line location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If variable size openings are used to compensate for asymmetric pumping distances, then flow uniformity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies local quality by providing different opening sizes at different locations around the pump liner. Specifically, openings closer to the pump port are made smaller while openings farther away are made larger, creating a non-uniform distribution that compensates for the asymmetric pumping geometry and achieves uniform gas flow throughout the chamber.
Solution Approach 2:
The patent changes the geometric parameter of the openings (size/diameter) to optimize flow conductance. By varying the opening dimensions based on their position relative to the pump port, the system adjusts local flow resistance to achieve overall flow uniformity despite asymmetric pumping conditions.
2Manufacturing precision
If individualized pumping liner designs are created to optimize flow conductance, then flow uniformity is improved, but lead time and cost increase
Solution Approach 1:
The patent employs parameter changes by systematically varying opening sizes based on their angular position and distance from the pump port. This allows for optimized flow conductance through a standardized design approach that can be manufactured without extensive trial-and-error testing, reducing lead time while maintaining flow uniformity.
3Manufacturing precision
If smaller openings are used closer to the pump port, then flow uniformity is improved, but pumping throughput decreases
Solution Approach 1:
The patent applies local quality by creating a gradient of opening sizes that are optimally tailored to their specific location. Openings closer to the pump port are smaller to prevent over-pumping and maintain uniformity, while openings farther away are larger to ensure sufficient gas removal, achieving both uniformity and adequate throughput.
Solution Approach 2:
The patent changes the opening size parameter as a function of position around the pump liner. This systematic parameter variation allows each opening to be optimized for its specific location, balancing the need for uniform flow with the requirement for sufficient pumping capacity across the entire chamber.
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 solution ensures uniform gas flow and pumping throughput across all valves, reducing the need for individualized designs and minimizing pressure drop, thereby achieving consistent gas distribution and reducing the complexity and cost of optimization processes.
Implementation Method 1
adjust flow conductance based on pressure differentials
Data Source
AI summary
Pump liners and process chambers with the pump liners are described. The pump liner has a ring-shaped body with an annular wall enclosing a process region. A plurality of circumferentially spaced openings provide fluid communication through the annular wall between the process region and a region outside of the ring-shaped body. Each of the plurality of circumferentially spaced openings has a self-adjusting valve assembly. Self-adjusting valves and processing methods are also described.