Electrostatic Chuck Projections With Amorphous Layer to Reduce Scratches
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Solution Overview
Problem
Existing electrostatic chucks cause scratches on the back surface of substrates due to the interaction between crystalline projections and the substrate during processing.
Innovation Solution
An electrostatic chuck with a dielectric member featuring upward projections that have a crystalline base and an amorphous surface layer formed by laser processing, which reduces the likelihood of scratches by minimizing grain separation and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crystalline projections are used on the electrostatic chuck surface, then the substrate can be held firmly, but scratches occur on the substrate back surface due to grain separation and detachment
Solution Approach 1:
The projection surface is divided into two distinct zones: a crystalline base providing structural strength and firm substrate holding, and an amorphous surface layer providing a smooth, scratch-free contact surface. This local differentiation allows each zone to fulfill its specific function optimally.
Solution Approach 2:
Each projection is constructed as a composite structure combining crystalline alumina (base) and amorphous alumina (surface layer). The crystalline phase provides mechanical strength while the amorphous phase provides a smooth, non-scratching surface, creating a material composite that solves both requirements simultaneously.
2Object-affected harmful factors
If laser processing is applied to form amorphous surface layer, then substrate scratches are reduced, but processing time and complexity increase
Solution Approach 1:
The laser processing induces a phase transition in the alumina surface material from crystalline to amorphous state. This phase change creates the desired amorphous surface layer that reduces scratches, while the process can be efficiently controlled through laser parameter optimization.
Solution Approach 2:
Traditional mechanical polishing methods are replaced with laser processing to create the amorphous surface layer. This substitution eliminates mechanical contact that could cause scratches while achieving the same surface smoothing effect through controlled thermal processing.
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 amorphous surface layer on the projections reduces substrate scratches and lowers friction, thereby minimizing damage to the substrate's back surface during processing.
Implementation Method 1
The amorphous surface layer on the projections reduces substrate scratches and lowers friction
Implementation Method 2
an electrostatic chuck for holding a substrate. The electrostatic chuck includes a dielectric member, and an electrode in the dielectric member
Data Source
AI summary
A technique reduces scratches on the back surface of a substrate held on an electrostatic chuck. An electrostatic chuck for holding a substrate includes a dielectric member, and an electrode in the dielectric member. The dielectric member includes an upper surface, and a plurality of projections projecting upward from the upper surface. The plurality of projections support a substrate. Each of the plurality of projections includes a crystalline base and an amorphous surface layer on the crystalline base.