Symmetric Etch Chamber Sealing for Uniform RF and Gas Distribution
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Solution Overview
Problem
Existing semiconductor processing chambers face challenges in achieving uniformity of gas flow, thermal distribution, and RF distribution, leading to non-uniform film deposition and increased dilution of process gases due to exposure of cooler components to the process environment.
Innovation Solution
The design includes a processing chamber with symmetrical gas flow, thermal, and RF distribution, isolated from the transfer region and cooler components, utilizing non-motorized lift pins and a substrate support system with a seal plate and RF gasket for improved film uniformity and reduced purge gas usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the processing chamber uses conventional asymmetric design with exposed cooler components, then the structure is simpler and easier to manufacture, but the film deposition uniformity deteriorates and purge gas usage increases
Solution Approach 1:
The chamber is divided into distinct functional zones: a processing region with symmetrical geometry for uniform deposition, and a separate transfer region for substrate handling. The pumping liner creates a physical barrier that segments the processing environment from the transfer environment, allowing each region to be optimized independently for its specific function.
Solution Approach 2:
The patent employs symmetrical design elements (opposite to conventional asymmetric designs) in the processing region to achieve uniform gas flow, thermal distribution, and RF distribution. The symmetrical chamber geometry, symmetrical gas distribution plates, and symmetrical positioning of components create balanced flow patterns that eliminate edge effects and improve film uniformity.
2Productivity
If cooler components are exposed to the process environment, then the chamber structure is simpler, but process gas dilution increases and material efficiency deteriorates
Solution Approach 1:
Cooler components such as the transfer mechanism, lift pins, and substrate handling equipment are extracted from the processing environment and placed in a separate transfer region. The pumping liner acts as a barrier that physically removes these cooler components from the hot processing zone, preventing them from cooling the process gases and reducing the need for purge gases.
Solution Approach 2:
The pumping liner serves as an intermediary barrier between the processing region and the transfer region. It allows the two regions to coexist in the same physical chamber while maintaining separate environments, enabling the transfer mechanism to operate in a cooler, lower-pressure environment while the processing region maintains its optimized temperature and pressure conditions.
3Loss of substance
If the chamber uses symmetrical design with isolated processing region, then film uniformity improves and purge gas usage reduces, but the substrate handling complexity increases
Solution Approach 1:
The substrate support system incorporates dynamic elements including a movable substrate support that can be raised and lowered, lift pins that extend and retract, and a transfer mechanism that moves substrates between chambers. These dynamic components enable automated substrate handling while maintaining the symmetrical processing region geometry, allowing the system to achieve both film uniformity and reduced purge gas usage.
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 design enhances film deposition uniformity and material efficiency by minimizing the need for purge gases and allowing independent operation of multiple processing chambers, while simplifying the substrate handling process.
Implementation Method 1
The seal plate may include an RF gasket disposed radially outward of the support plate. The substrate support and the seal plate may be vertically translatable within the chamber body between a transfer position in which the RF gasket is vertically spaced apart from a bottom surface of the pumping liner and a process position in which the RF gasket is in contact with the bottom surface of the pumping liner.
Implementation Method 2
Each of the plurality of lift pins may include a spring-loaded plunger that is coupled with the base of the chamber body. Each of the plurality of lift pins may include a pin member that is biased by the spring-loaded plunger in an upward direction.
Data Source
AI summary
Exemplary semiconductor processing systems may include a chamber having a body having a sidewall and a base. The chamber may include a pumping liner atop the body and a faceplate atop the pumping liner. The chamber may include a substrate support. The substrate support may include a plate and a shaft. The chamber may include a seal plate coupled with the shaft below the plate. The seal plate may have a greater diameter than the plate. The seal plate may include an RF gasket outward of the plate. The substrate support and the seal plate may be translatable between a transfer position in which the RF gasket is vertically spaced apart from the pumping liner and a process position in which the RF gasket is in contact with the pumping liner. A processing region may be isolated from an environment below the sealing plate when in the process position.