Silicon Member Coating for Thermal Stress Crack Suppression
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Solution Overview
Problem
Silicon members used in heated conditions, such as in semiconductor manufacturing and heat treatment, are prone to cracking due to thermal stress and existing surface scratches and micro-cracks, which can lead to reduced productivity and quality.
Innovation Solution
A silicon member with a coating layer composed of silicon-based materials like silicon oxide or nitride films, applied through oxidation or nitridation treatments, to cover and eliminate existing scratches and micro-cracks, and potentially re-forming the coating layer to prevent contamination and further scratching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a silicon member is used as a holding plate in heated conditions, then thermal conductivity is improved and temperature uniformity is enhanced, but the silicon member is prone to cracking due to thermal stress and surface scratches
Solution Approach 1:
The patent applies preliminary action by performing surface treatment (grinding, polishing, or etching) before the silicon member is put into service to remove scratches and micro-cracks that would serve as crack initiation sites. This preventive measure eliminates the root cause of thermal stress cracking while preserving the high thermal conductivity benefit of silicon
Solution Approach 2:
The patent converts the harmful effect of thermal stress into a beneficial outcome by deliberately introducing compressive stress through surface treatment processes. This compressive stress counteracts the tensile thermal stress that occurs during heating, transforming the potential harm into a protective mechanism that prevents cracking
2Manufacturing precision
If the silicon member surface is ground or polished to remove scratches, then surface smoothness is improved, but micro-cracks are created that lead to cracking under thermal stress
Solution Approach 1:
The patent applies preliminary action by performing etching after polishing to remove the damaged surface layer containing micro-cracks. This sequential treatment ensures that the surface is both smooth and free of subsurface defects that would initiate cracking under thermal stress
Solution Approach 2:
The patent changes the surface treatment parameters by transitioning from mechanical methods (grinding, polishing) to chemical methods (etching). This parameter change allows removal of micro-cracks without introducing new damage, as the chemical etching process dissolves the damaged layer without mechanical stress
3Ease of manufacture
If quartz is used as a holding plate, then cost is reduced and heat resistance is improved, but thermal conductivity is poor leading to temperature non-uniformity
Solution Approach 1:
The patent changes the material parameter from quartz to silicon, which has fundamentally different thermal conductivity properties. Silicon's higher thermal conductivity enables uniform heat distribution across the holding plate, solving the temperature non-uniformity problem while maintaining cost-effectiveness and heat resistance
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 reduces the occurrence of cracking in silicon members during high-temperature use, improving temperature uniformity and productivity by eliminating surface imperfections and preventing contamination, while maintaining efficient processing times.
Implementation Method 1
the coating layer is composed of a product of silicon formed by reaction of the silicon on the surface
Implementation Method 2
Since thermal conductivity of the silicon plate is higher than that of quartz, the overall temperature uniformity is improved
Data Source
AI summary
A silicon member and a method of producing the silicon member are provided. Cracking is suppressed in the silicon member even if the silicon member is used in a condition where it is heated. The silicon member 10 includes a coating layer 11 that coats a surface of the silicon member 10, wherein the coating layer 11 is composed of a product of silicon formed by reaction of the silicon on the surface, and a thickness of the coating layer is 15 nm or more and 600 nm or less. It is preferable that the coating layer is a silicon oxide film or a silicon nitride film.