Burled Substrate Table Surface Hardening for Wafer Release
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Solution Overview
Problem
Lithographic processes face challenges in maintaining tribological properties such as friction, hardness, and wear resistance on substrate tables, which are crucial for precise alignment and operation of wafers, as they are sensitive to uneven surfaces and can become stuck due to smooth contact.
Innovation Solution
Treatment of substrate table surfaces with radiation or heat to enhance properties like surface strength, hardness, roughness, coefficient of friction, chemical resistance, and wear resistance, using methods such as laser peening to manipulate the contact layer properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If substrate table surfaces are made smooth for precise wafer alignment, then alignment precision is improved, but wafers become stuck together due to excessive adhesion
Solution Approach 1:
The patent applies local quality by creating a burled surface with localized roughness features (peaks and valleys) on the substrate table surface. This burled structure provides different local properties: the peaks maintain contact for precision while the valleys create air gaps that reduce adhesion. The surface is not uniformly smooth or rough, but has spatially varying characteristics that simultaneously achieve alignment precision and prevent sticking.
2Ease of operation
If substrate table surfaces are made rough to reduce adhesion, then wafer release is improved, but alignment precision deteriorates due to surface unevenness
Solution Approach 1:
The burled surface creates local quality variations where peaks provide precise contact points for alignment while valleys provide release spaces. The controlled roughness is localized to specific regions rather than being uniform, allowing the surface to maintain both precision and ease of release operations.
3Reliability
If substrate table surfaces are treated to increase hardness and wear resistance, then durability is improved, but surface roughness control becomes more difficult
Solution Approach 1:
The burled surface structure is created preliminarily before the hardness treatment process. By establishing the roughness features first, then applying radiation or heat treatment to harden the surface, the patent ensures that the burled structure is formed when the material is more formable, and subsequent hardening preserves rather than degrades the surface topology.
Solution Approach 2:
The patent changes material parameters through radiation or heat treatment to increase hardness and wear resistance while maintaining the burled surface morphology. The parameter changes affect the bulk material properties without necessarily altering the surface roughness characteristics that were previously established.
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
Enhances the durability and performance of substrate tables by improving wear resistance and reducing friction, thereby maintaining accurate lithographic processes and extending the lifespan of substrate tables.
Implementation Method 1
treating a burled surface of an object using radiation or heat
Implementation Method 2
treating a burled surface of an object using radiation or heat
Implementation Method 3
using methods such as laser peening to manipulate the contact layer properties
Data Source
AI summary
A method includes treating a burled surface of an object using radiation or heat and setting parameters of the radiation or heat to effectuate a predetermined surface strength, hardness, roughness, coefficient of friction, chemical resistance, wear resistance, and/or corrosion of the burled surface.