Wafer Support Pin Vertical Adjustment Vibration Control
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Solution Overview
Problem
Large diameter semiconductor wafers are prone to breakage during high-speed drying processes due to increased deflection and vibration caused by the existing substrate holding apparatuses, which hold the wafer periphery with four chucks at equal intervals, leading to a natural frequency resonance.
Innovation Solution
A substrate holding apparatus with vertically movable support posts and chucks, featuring support pins that contact the wafer's lower surface, minimizing deflection and varying the natural frequency to prevent vibration and breakage, even at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If four chucks are used to hold the periphery of large diameter wafers at equal intervals, then the device complexity is reduced and ease of operation is improved, but the deflection amount due to wafer weight increases and vibration occurs at natural frequency
Solution Approach 1:
The support function is segmented into two independent systems: peripheral support by chucks and central support by support pins. This segmentation allows each support element to perform its specific function optimally - chucks provide peripheral holding while support pins provide central support to reduce deflection, resolving the contradiction between operational simplicity and structural stability.
Solution Approach 2:
The support structure transitions from two-dimensional peripheral support (chucks at the wafer edge) to three-dimensional support by adding vertical support pins from the base. This dimensional change provides support at multiple levels (peripheral and central), reducing wafer deflection while maintaining the simplicity of the four-chuck configuration.
2Device complexity
If four chucks are arranged at equal intervals to hold the wafer periphery, then the device structure is simplified, but the rotational speed approaches the natural frequency causing increased vibration
Solution Approach 1:
The support function is segmented into two independent systems: peripheral support by chucks and central support by support pins. This segmentation allows each support element to perform its specific function optimally - chucks provide peripheral holding while support pins provide central support to reduce deflection, resolving the contradiction between operational simplicity and structural stability.
Solution Approach 2:
The support structure transitions from two-dimensional peripheral support (chucks at the wafer edge) to three-dimensional support by adding vertical support pins from the base. This dimensional change provides support at multiple levels (peripheral and central), reducing wafer deflection while maintaining the simplicity of the four-chuck configuration.
3Device complexity
If the wafer is held only by peripheral chucks, then the device structure is simple, but large diameter wafers experience increased deflection and breakage during high-speed rotation
Solution Approach 1:
The support function is segmented into two independent systems: peripheral support by chucks and central support by support pins. This segmentation allows each support element to perform its specific function optimally - chucks provide peripheral holding while support pins provide central support to reduce deflection, resolving the contradiction between operational simplicity and structural stability.
Solution Approach 2:
The support structure transitions from two-dimensional peripheral support (chucks at the wafer edge) to three-dimensional support by adding vertical support pins from the base. This dimensional change provides support at multiple levels (peripheral and central), reducing wafer deflection while maintaining the simplicity of the four-chuck configuration.
Data Source
AI summary
A substrate holding apparatus that can minimize a deflection amount of a substrate due to its own weight and can suppress vibration of the substrate at the time of rotation of the substrate even if a diameter of the substrate becomes large is disclosed. The substrate holding apparatus holds a periphery of a substrate and rotates the substrate. The substrate holding apparatus includes a plurality of support posts supported by a base and vertically movable relative to the base, a plurality of chucks respectively provided on the plurality of support posts and configured to hold the periphery of the substrate, and at least one support pin configured to support a lower surface of the substrate held by the plurality of chucks.