SiC Wafer Polishing With Parallel Si and C Surface Processing
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Solution Overview
Problem
SiC wafers require longer processing times due to the difference in mechanical and chemical properties of their Si and C surfaces, leading to inefficiencies in polishing processes and increased waiting times for subsequent wafers.
Innovation Solution
A polishing apparatus with two chuck tables and a turntable system that allows simultaneous polishing of both Si and C surfaces on SiC wafers by alternating the positions of the chuck tables, enabling parallel processing of the surfaces using separate polishing assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single chuck table is used to polish SiC wafers, then the polishing process is simple, but the total processing time increases due to sequential processing of Si and C surfaces
Solution Approach 1:
The polishing apparatus is segmented into two independent chuck tables (first and second chuck tables), each capable of holding and processing SiC wafers separately. This segmentation allows parallel processing of different surfaces (Si surface on one table, C surface on the other table), thereby reducing total processing time while maintaining manageable system complexity through modular design
Solution Approach 2:
The patent merges multiple functions into a single integrated apparatus: both chuck tables share a common turntable mechanism for positioning, a unified polishing assembly that can service both tables, and integrated control systems. This merging approach enables parallel processing capability while avoiding the complexity of completely separate polishing systems
2Manufacturing precision
If polishing time for Si surface is extended to accommodate longer processing requirements, then Si surface quality is improved, but the waiting time for subsequent wafers increases
Solution Approach 1:
The apparatus maintains continuous useful action by eliminating idle waiting time. While the first chuck table is polishing the Si surface of one wafer, the second chuck table simultaneously processes the C surface of another wafer. This continuous operation ensures that no time is wasted with equipment or wafers idle, thereby reducing waiting time for subsequent wafers while maintaining high polishing quality
Solution Approach 2:
The system performs preliminary actions by pre-positioning and pre-processing wafers on the second chuck table while the first table is occupied. The turntable mechanism allows wafers to be loaded and prepared in advance, so that when one polishing cycle completes, the next wafer is already in position and ready for immediate processing, eliminating waiting time
Data Source
AI summary
A polishing apparatus for polishing SiC wafers includes at least two chuck tables configured to hold the SiC wafers; a turntable, on which the at least two chuck tables are arranged; a polishing assembly configured to polish a surface of one of the SiC wafers held on one of the at least two chuck tables located at a polishing position with a polishing pad; and a C-surface polishing assembly configured to, while the surface of the one of SiC wafers held on the one of the at least two chuck tables located at the polishing position in the polishing assembly is being polish-processed, polish a C surface of another SiC wafer held on another of the at least two chuck tables not located at the polishing position with a C-surface polishing pad. The polishing assembly and the C-surface polishing assembly polish the respective surfaces of each of the SiC wafers.