Three-Point Substrate Centering for Faster Wafer Alignment
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Solution Overview
Problem
Conventional substrate processing apparatuses face inefficiencies in centering operations, leading to reduced throughput due to the need for multiple steps and potential misalignment of the substrate's center with the substrate support, which can affect processing quality.
Innovation Solution
A centering technique utilizing three contact members positioned at specific angles and distances relative to the substrate support's center, allowing for minute movements to align the substrate's center with the support's center, ensuring accurate and efficient alignment through controlled movement mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional two-step centering operation is used (measuring eccentricity then pushing substrate with a pusher), then the substrate center can be aligned with the substrate support center, but the throughput is reduced due to multiple steps
Solution Approach 1:
The centering device divides the substrate circumference into three sections with contact members positioned at specific angles (40-60 degrees from reference lines). Each contact member independently applies force to push the substrate center toward the support center, enabling parallel adjustment across multiple points simultaneously, thus improving throughput while maintaining precision
Solution Approach 2:
The contact members are positioned at predetermined reference positions separated by reference distances longer than the substrate radius before the centering operation begins. This preliminary positioning allows the minute movement mechanism to systematically adjust each contact member's distance from the support center, streamlining the centering process into a single integrated operation rather than separate measurement and correction steps
2Manufacturing precision
If contact members are positioned closer to the substrate center to improve alignment precision, then centering accuracy increases, but the risk of substrate damage increases
Solution Approach 1:
The contact members apply localized pushing forces at specific angular positions (40-60 degrees from reference lines) rather than concentrated force at the center. This distributed local action achieves precise centering while reducing peak stress on the substrate, preventing damage during the alignment process
Solution Approach 2:
The minute movement mechanism dynamically adjusts the distance of each contact member from the substrate support center during the centering operation. This dynamic control allows the system to optimize the balance between alignment precision and substrate safety, moving contact members to appropriate positions based on real-time alignment requirements rather than using fixed aggressive positioning
Data Source
AI summary
This invention relates to a centering device, a centering method and a substrate processing apparatus. substrate supported on a substrate support is surrounded by a first contact member located at a first reference position, a second contact member located at a second reference position and a third contact member located at a third reference position in the horizontal plane. These three contact members gradually approach the substrate while keeping distances from a center of the substrate support equal by repeating the minute movements. Considering that the minute movement directions of the second and third contact members are different from each other, first and second angles are each set in a range of 40° or larger and 60° or smaller.