SiC Protrusion Coating Segmentation for Particle Reduction
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Solution Overview
Problem
The existing substrate holding members in semiconductor manufacturing equipment face issues with particle generation due to peeling-off or cracking of the SiC film protective layers on the protrusions, caused by differences in material properties and thermal expansion rates, leading to stress propagation and circuit breakage.
Innovation Solution
A substrate holding member design where the protective layer is formed only on the upper end surface and a part of the side surface of the protrusions, made from materials like silicon carbide, diamond-like carbon, or other ceramics, ensuring the layer is discontinuous between the edge and lower end, reducing stress propagation and material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the entire surface of the substrate holding member is coated with a SiC film, then wear resistance is improved, but peeling-off or cracking occurs due to stress propagation from thermal expansion differences
Solution Approach 1:
The protective layer is segmented into multiple regions: a first region covering the upper end surface, a second region covering part of the side surface, and a third exposed region. This segmentation prevents continuous stress propagation paths, reducing peeling-off and cracking while maintaining wear resistance in critical areas.
Solution Approach 2:
Different regions of the protective layer have different coverage areas and functions. The first region provides comprehensive protection on the upper surface, the second region provides partial side protection, and the third region is intentionally exposed to break stress continuity. This local differentiation optimizes both wear resistance and stress management.
2Reliability
If a SiC film is coated on the protrusions, then electroconductivity is maintained, but particle generation occurs due to long-term peeling-off or cracking
Solution Approach 1:
By segmenting the protective layer coverage and creating an exposed region, the patent prevents continuous peeling-off that generates particles. The discontinuous structure breaks potential crack paths, significantly reducing particle generation while preserving electroconductivity through the remaining coated regions.
3Strength
If the protective layer is formed on the entire surface, then comprehensive protection is achieved, but stress propagation causes peeling-off or cracking
Solution Approach 1:
The protective layer is divided into covered regions (first and second regions) and an exposed region (third region). This segmentation maintains protective coverage where needed while creating stress-relief zones that prevent continuous peeling-off and cracking, improving overall structural stability.
Solution Approach 2:
The patent applies protective coating locally rather than uniformly. The first region covers the upper end surface for maximum protection, the second region covers part of the side surface, and the third region is exposed. This local quality approach balances protection needs with stress management.
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
This design effectively suppresses peeling-off and cracking of the protective layer, reducing particle generation and maintaining electroconductivity while minimizing material usage and stress propagation.
Implementation Method 1
the base portion and the SiC film, which are made from the same material by using different methods, differ slightly in properties, such as coefficient of linear expansion, modulus of elasticity, density, hardness, and crystallizability; and therefore a stress is generated due to the difference in thermal expansion rate as temperature changes
Implementation Method 2
a substrate holding member that includes a base body and a plurality of protrusions formed on a surface of the base body is used to hold a wafer when exposing the wafer to light
Data Source
AI summary
Provided is a substrate holding member that includes a base body and a plurality of protrusions formed on a surface of the base body and that is capable of suppressing generation of particles due to peeling-off or cracking of protective layers of the protrusions. A substrate holding member includes a base body and a plurality of protrusions formed on a surface of the base body. Each of the protrusions includes a base portion and a protective layer, the base portion having a flat upper end surface and being made from a silicon carbide sintered compact, the protective layer being made of silicon carbide. The protective layer includes a region on at least a part of the base portion from an edge of the upper end surface to a lower end of the base portion, the region being exposed along an entire periphery. Preferably, the protective layer is formed so as to cover at least only a part of an upper portion of the base portion, the upper portion including the upper end surface.