Vacuum Substrate Holder Structure for Curved Wafer Flatness
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Solution Overview
Problem
Existing substrate holding devices are inadequate in attracting and holding substrates with non-flat, bent, or curved shapes due to insufficient attraction force, which fails to meet the increasing standards of flatness requirements.
Innovation Solution
A substrate holding member with a flat-plate-shaped base body featuring vent holes, grooved portions, and convex portions that reduce pressure loss and enhance negative pressure, allowing for effective attraction of curved substrates while minimizing deformation and positional displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the cross-sectional area of the grooved portion is increased to reduce pressure loss and enhance negative pressure, then the attraction force for curved substrates is improved, but the base body may deform into a concave shape
Solution Approach 1:
The base body is designed with non-uniform thickness, being thicker at the center and thinner at the periphery. This local variation in thickness compensates for the potential concave deformation caused by the large cross-sectional area grooved portions, maintaining the overall flatness required for attracting curved substrates
Solution Approach 2:
The grooved portions are positioned asymmetrically at the peripheral region of the base body, away from the center. This asymmetric placement allows the grooved portions to be located where the base body is naturally thinner, reducing the risk of concave deformation while still providing sufficient attraction force through the increased cross-sectional area
2Device complexity
If conventional substrate holding devices are used, then the structure is simple, but insufficient attraction force cannot be applied to largely curved substrates
Solution Approach 1:
The cross-sectional area of the grooved portions is specifically designed to be 1.2 mm² or more, which is a significant increase compared to conventional designs. This parameter change directly enhances the negative pressure generation capability, providing sufficient attraction force for largely curved substrates while maintaining a relatively simple overall structure
Solution Approach 2:
The invention introduces a new dimensional consideration by specifying the cross-sectional area parameter of the grooved portions rather than just their length or width alone. This area-based design approach enables better control over pressure loss and attraction force while keeping the structural complexity manageable
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 enables the attraction of substrates with good flatness, even those that are largely curved, by increasing the cross-sectional area of the grooved portions and strategically arranging convex portions to suppress deformation and pressure loss, resulting in improved flatness and reduced positional variations.
Implementation Method 1
When the cross-sectional area of the grooved portion in the direction perpendicular to a flow path direction is 1.2 mm2 or greater, the pressure loss of the flow path is reduced and the negative pressure for attracting a substrate is increased
Implementation Method 2
a plurality of upper-surface convex portions that are formed so as to protrude upward from the upper surface of the base body; and an upper-surface ring-shaped convex portion that is formed in a ring shape along an outer periphery of the upper surface of the base body so as to protrude upward from the upper surface
Data Source
AI summary
A substrate holding member includes a flat-plate-shaped base body that has at least one vent hole and a grooved portion, the at least one vent hole opening in an upper surface, the grooved portion communicating with the at least one vent hole and opening in a lower surface; a plurality of upper-surface convex portions that are formed so as to protrude upward from the upper surface of the base body; and an upper-surface ring-shaped convex portion that is formed in a ring shape along an outer periphery of the upper surface of the base body so as to protrude upward from the upper surface, wherein a cross-sectional area of the grooved portion in a direction perpendicular to a flow path direction is 1.2 mm2 or greater.