Offset-Aperture Choke Plate for Uniform Wafer Processing
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Solution Overview
Problem
Temperature non-uniformity and contamination issues in semiconductor processing due to faceplate sublimation and stainless steel component reactions with purge gases, leading to inconsistent substrate processing and potential contamination of substrates.
Innovation Solution
The introduction of a choke plate with a purging inlet and outlets, along with a multi-piece isolator system, to improve temperature uniformity and reduce contamination by directing purge gas into the reaction volume and using thermally conductive materials to minimize heat transfer and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional substrate processing system designs are used, then the system structure is simple, but the purge gas flow rate is insufficient to prevent faceplate sublimation and temperature non-uniformity
Solution Approach 1:
The choke plate is divided into multiple functional sections: a flange with purging inlet, a body with purging outlets and apertures, and a rim with additional outlets. This segmentation allows different regions to perform specific functions (purge gas introduction, substrate processing, exhaust) thereby achieving effective purging and temperature uniformity without requiring a completely redesigned complex system
Solution Approach 2:
The choke plate serves multiple functions simultaneously: it acts as a flow control element, a purging system, a thermal management component, and a structural support. By integrating these functions into a single component, the patent achieves effective faceplate purging and temperature control without increasing overall system complexity
2Temperature
If high purge gas flow rate is used to prevent faceplate sublimation, then temperature uniformity is improved, but the risk of stainless steel component corrosion and contamination increases
Solution Approach 1:
The patent extracts the purging function from the main chamber environment by introducing purge gas through dedicated outlets on the choke plate that directly target the faceplate region. This localized extraction of purging action prevents the need for high overall flow rates that would cause corrosion, while still achieving effective sublimation prevention at the critical faceplate area
Solution Approach 2:
The choke plate acts as an intermediary component between the purge gas source and the faceplate. It controls and directs the purge gas flow through specific outlets, mediating the interaction between the gas and the faceplate to achieve effective purging while minimizing exposure of stainless steel components to high flow rates and corrosive environments
3Object-generated harmful factors
If stainless steel components are coated to prevent reaction with purge gases, then contamination risk is reduced, but the coating can flake off at high temperatures and expose the metal to oxidation and corrosion
Solution Approach 1:
The patent changes the operational parameters by reducing the purge gas flow rate through efficient localized purging. This parameter change decreases the thermal and mechanical stress on coatings, preventing flaking while maintaining effective sublimation prevention, thereby preserving coating integrity and reducing contamination risk
Solution Approach 2:
The patent extracts the purging action from the general chamber environment and concentrates it at the faceplate interface. This extraction reduces the overall exposure of stainless steel components to purge gases, minimizing oxidation and corrosion risks without requiring heavy reliance on protective coatings
4Device complexity
If the purging inlet is positioned at the bottom of the chamber, then the system design is simple, but the required purge gas flow rate is too high to be effective
Solution Approach 1:
The patent moves the purging inlet from the bottom (vertical dimension) to the choke plate structure, and creates multiple outlets distributed across different locations. This dimensional redistribution of purging points allows effective coverage of the faceplate area with lower overall gas flow rates, achieving efficient purging without excessive gas consumption
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 enhances temperature uniformity during substrate processing, reduces the risk of contamination, and decreases the required purge gas flow rate, effectively addressing sublimation and contamination issues in semiconductor processing.
Implementation Method 1
Each of the plurality of purging outlets is fluidly coupled with the first aperture... direct purge gas into the reaction volume... properly purged during substrate processing
Implementation Method 2
minimize the risk of stainless steel components within substrate processing environments from reacting with purge gases... minimize heat transfer and oxidation
Data Source
AI summary
Exemplary choke plates for use in a substrate processing system may include a plate defining a first aperture through the plate and a second aperture through the plate. The second aperture may be laterally offset from the first aperture. The plate may include a flange that defines a purging inlet. The plate may include a rim defining a plurality of purging outlets that are fluidly coupled with the purging inlet. Each of the plurality of purging outlets may be fluidly coupled with the first aperture.