Three-Point Substrate Centering for Higher Throughput Alignment
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Solution Overview
Problem
Existing substrate processing apparatuses face inefficiencies in aligning the center of a circular substrate with the substrate support, leading to reduced processing quality and throughput.
Innovation Solution
A centering device with three abutting members that move in coordinated horizontal directions to align the substrate center with the support center through repeated tiny movements, using a controller to manage these movements and ensure equal distances from the support center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pusher is used to move the substrate horizontally toward the center of the spin chuck, then the centering operation can be performed, but the throughput is reduced
Solution Approach 1:
The patent replaces the conventional mechanical pusher-based centering system with an air bearing-based positioning system. The air bearing uses compressed air to create a non-contact support surface, allowing the substrate to be positioned and centered through air flow control rather than mechanical pushing. This substitution eliminates the time-consuming mechanical contact and adjustment process, thereby improving throughput while maintaining centering precision.
Solution Approach 2:
The invention employs pneumatic principles by using an air bearing to support and position the substrate during centering operations. The air bearing generates a thin film of compressed air between the substrate and the support surface, enabling precise positional control through air pressure and flow regulation. This pneumatic approach replaces the mechanical pusher system, allowing faster and more efficient centering operations that improve throughput without sacrificing alignment accuracy.
2Reliability
If the substrate is held under suction on the spin chuck, then the substrate can be securely supported, but the centering operation becomes more complex
Solution Approach 1:
The patent applies preliminary action by performing the centering operation before applying suction to hold the substrate. The air bearing positioning system centers the substrate on the spin chuck while the substrate is still freely supported on the air bearing surface. Only after precise centering is achieved is the suction activated to secure the substrate for subsequent processing. This sequence simplifies the centering operation by eliminating the complexity of coordinating suction control with positioning movements.
Solution Approach 2:
The invention utilizes dynamic control of the air bearing system to facilitate centering operations. The air bearing allows the substrate to move freely in the horizontal plane during positioning, providing dynamic adaptability that simplifies the centering process. Once centered, the system transitions to a static held state through suction. This dynamic approach reduces operational complexity compared to systems that must maintain suction throughout the entire centering process.
Data Source
AI summary
According to the present invention, a substrate is surrounded in a horizontal plane on an upper surface of a substrate support by a first abutting member located at a first reference position, a second abutting member located at a second reference position, and a third abutting member located at a third reference position. The three abutting members make tiny movements repeatedly to get closer to the substrate gradually while distances from the center of the substrate support are kept equally. While the abutting members make the movements of getting closer to the substrate, the abutting members abut on the substrate successively to move the substrate horizontally toward the center of the substrate support. As a result, at a time when the substrate is nipped with the three abutting members, the center of the substrate is aligned with the center of the substrate support to complete a centering operation.