Substrate Holder Geometry for Eccentric Laser Wafer Separation
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Solution Overview
Problem
Existing substrate processing methods risk damaging the substrate holding surface due to laser light radiation during the processing of substrates, particularly when the combined wafer is held eccentrically, leading to potential misalignment and exposure of the holding surface to laser light.
Innovation Solution
A substrate processing apparatus with a substrate holder having a diameter smaller than the substrate, equipped with a light shield and wafer drop prevention pins, along with a laser radiation system that adjusts the laser light radiation positions based on the substrate's eccentricity, ensuring the laser light is directed away from the holder surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the substrate holder diameter is made smaller than the substrate diameter, then the substrate holding surface is protected from laser light damage, but the substrate may become unstable or misaligned during processing
Solution Approach 1:
The substrate holder is designed with a recessed portion that creates a stepped structure. This segmentation allows the holder to have a smaller overall diameter (protecting from laser damage) while providing a dedicated holding area for the substrate. The recessed portion acts as a separate functional zone that maintains substrate positioning without requiring the entire holder surface to be exposed.
Solution Approach 2:
The solution transitions from a two-dimensional planar holder surface to a three-dimensional stepped structure with a recessed portion. By adding the vertical dimension (depth of recess), the holder can protect the substrate from laser damage at the periphery while maintaining precise alignment through the recessed holding area. This dimensional change resolves the contradiction between protection and precision.
2Productivity
If laser light is radiated to process the substrate, then the processing efficiency is improved, but the substrate holding surface may be damaged by the laser light
Solution Approach 1:
The harmful effect of laser light on the holding surface is extracted and isolated by creating a recessed portion. The laser processing occurs on the substrate surface while the holding surface is physically extracted from the laser path through the recessed structure. This allows high-power laser processing to proceed efficiently without compromising holding surface integrity.
Solution Approach 2:
The recessed portion acts as an intermediary structure between the substrate and the external environment. It allows the substrate to be held securely while preventing direct exposure of the holding surface to laser light. The recessed geometry serves as a protective mediator that enables both efficient laser processing and holding surface preservation.
3Adaptability or versatility
If the substrate is held eccentrically on the holder, then the substrate can be accommodated, but the holding accuracy and processing precision deteriorate
Solution Approach 1:
The recessed portion creates a localized high-precision holding zone with different geometric properties than the rest of the holder surface. This local quality change ensures that even if the substrate is somewhat eccentrically positioned, the critical holding area within the recess provides accurate positioning and alignment, maintaining manufacturing precision while accommodating substrate variations.
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
The solution effectively suppresses damage to the substrate holding surface and improves the accuracy of substrate separation by preventing laser light exposure to the holder, enhancing processing precision and reducing the risk of substrate drop.
Implementation Method 1
a laser radiator configured to radiate laser light to the substrate on the holding surface
Implementation Method 2
a rotator configured to rotate the substrate on the holding surface around a rotation axis of the substrate holder
Data Source
AI summary
A substrate processing apparatus of processing a substrate includes a substrate holder having a holding surface on which the substrate is held; a rotator configured to rotate the substrate on the holding surface around a rotation axis of the substrate holder; and a laser radiator configured to radiate laser light to the substrate on the holding surface. The holding surface of the substrate holder has a diameter smaller than that of the substrate.