Pin Lifter Assembly Gap Reduction for Plasma Erosion
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Solution Overview
Problem
In substrate processing systems, manufacturing tolerances lead to gaps between components, causing increased exposure to plasma and gases, resulting in erosion and arcing issues that limit power application and increase maintenance downtime.
Innovation Solution
The implementation of pin lifter assemblies with a clamp assembly that secures the lower end of the lift pin against vertical movement while allowing horizontal movement, and the use of a pin bearing and ceramic insert to reduce gaps between the lift pin and the ceramic layer, preventing arcing and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manufacturing tolerances are relaxed to ease production, then ease of manufacture is improved, but gap width between components increases causing erosion and arcing
Solution Approach 1:
A ceramic insert is introduced as an intermediary component between the lift pin and the baseplate. This insert acts as a mediator that maintains a precise, minimal gap between moving and stationary components, thereby preventing harmful plasma exposure and arcing while allowing the lift pin to move freely during substrate lifting operations.
Solution Approach 2:
The gap-problematic region is isolated by extracting the ceramic insert as a separate, precision-machined component. This allows the gap to be controlled and minimized in the critical area between the lift pin and ceramic layer, preventing erosion and arcing without compromising the overall manufacturing tolerances of other components.
2Reliability
If gap width between lift pin and ceramic layer is reduced to prevent erosion and arcing, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The assembly is segmented into distinct components: the lift pin, the ceramic insert, and the baseplate. The ceramic insert is provided with a precisely controlled inner radius that defines a minimal gap relative to the lift pin shaft outer radius. This segmentation allows the critical gap dimension to be controlled in a separate, precision-machined component rather than relying on the cumulative tolerances of multiple parts.
Solution Approach 2:
The ceramic insert serves as an intermediary that bridges the lift pin and baseplate with a precisely controlled gap. This mediator component maintains the reliability-enhancing minimal gap while absorbing manufacturing tolerances through its own precision machining, thereby protecting the overall assembly from tolerance accumulation.
3Reliability
If clamp assembly secures lift pin against vertical movement to improve reliability, then reliability is improved, but device complexity increases
Solution Approach 1:
The clamp assembly is merged with the existing baseplate structure, integrating the clamping function into the substrate support assembly rather than adding a completely separate mechanism. The clamp assembly includes a clamp ring that fits over the lift pin lower end and engages with the baseplate, combining securing and guiding functions in a single integrated component.
Solution Approach 2:
The clamp assembly serves multiple functions: it secures the lift pin against vertical movement, guides horizontal movement during substrate lifting, and integrates with the baseplate structure. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved reliability.
Data Source
AI summary
A pin lifter assembly for a substrate support in a substrate processing system includes a lift pin having a shaft, an upper end, and a lower end, and an insert arranged around the lift pin. The insert defines a gap between the insert and the lift pin. A clamp assembly is arranged around the lower end of the lift pin. The lower end of the lift pin is secured within the clamp assembly such that the clamp assembly prevents vertical movement of the lift pin relative to the clamp assembly. The clamp assembly is configured to allow horizontal movement of the lower end of the lift pin within the clamp assembly.