Wafer Centering Mechanism for Accurate Polishing Alignment
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Solution Overview
Problem
Existing substrate processing techniques, such as those described in PTL 1, fail to ensure accurate positioning of substrates with deformed portions like orientation flats or notches that are not pre-aligned.
Innovation Solution
A substrate processing apparatus equipped with a table, a pad holder, an elevating mechanism, and at least three centering mechanisms. The centering mechanisms include rotation shafts and centering members with first and second contact portions to accurately position substrates by pushing them in a center direction, even when deformed portions are not pre-aligned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-direction centering mechanism is used, then the device complexity is reduced, but the positioning accuracy of substrates with deformed portions is insufficient
Solution Approach 1:
The centering mechanism is segmented into multiple independent centering mechanisms (at least three), each with its own rotation shaft and centering member. Each centering member has first and second contact portions that can independently contact the substrate from different directions, allowing the system to handle substrates with deformed portions while maintaining positioning accuracy.
Solution Approach 2:
The centering members are designed to be rotatable around rotation shafts, enabling dynamic adjustment of the contact portions. This rotational capability allows the centering members to adapt to substrates with deformed portions by rotating to appropriate contact positions, thereby achieving accurate positioning without increasing overall system complexity.
2Manufacturing precision
If multiple contact portions are added to handle deformed substrates, then the positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
Each centering member serves multiple functions: it can contact the substrate with its first contact portion, rotate to contact with the second contact portion, and work in coordination with other centering mechanisms. This multi-functionality allows a single centering member design to handle various substrate conditions (with or without deformed portions) without requiring entirely separate mechanisms for each case.
Solution Approach 2:
The centering members are designed with asymmetric first and second contact portions that are positioned to contact the substrate from different directions. This asymmetric design allows the mechanism to accommodate substrates with deformed portions (such as orientation flats or notches) by selecting the appropriate contact portion, thereby achieving accurate positioning without requiring symmetric, overly complex mechanisms.
3Ease of operation
If the substrate is assumed to be pre-aligned, then the positioning process is simplified, but the positioning accuracy fails when deformed portions are present
Solution Approach 1:
The centering mechanisms automatically adapt to the substrate's actual orientation without requiring pre-alignment. The rotatable centering members self-adjust by rotating around their rotation shafts until the appropriate contact portions make contact with the substrate, including any deformed portions. This self-service capability maintains ease of operation while ensuring positioning accuracy regardless of the substrate's initial state.
Data Source
AI summary
A substrate processing apparatus includes a table, a pad holder, an elevating mechanism, and at least three centering mechanisms. The table is for supporting a substrate. The pad holder is for holding a polishing pad for polishing the substrate supported by the table. The elevating mechanism is for elevating the pad holder with respect to the substrate. The at least three centering mechanisms are for pushing the substrate supported by the table in a center direction of the table to position the substrate. The at least three centering mechanisms each include a rotation shaft arranged in a peripheral area of the table and a centering member mounted to the rotation shaft.