Substrate Position Aligner for Vertical Wafer Handling
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Solution Overview
Problem
Substrate grippers face challenges in holding vertical substrates with orientation cuts, particularly in CMP systems, as the cuts interfere with proper gripping and rotation, leading to potential dropping during processing.
Innovation Solution
A substrate position aligner is introduced, which includes a substrate holder assembly, rotation mechanism, drive and idler rollers, and sensors to rotate the substrate so that the orientation cut is positioned at the bottom, allowing grippers to securely grip the substrate from the sides while avoiding the cut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate grippers are used to hold vertical substrates with orientation cuts, then substrate transfer is enabled, but the orientation cut interferes with proper gripping causing improper holding or dropping
Solution Approach 1:
The substrate rotation mechanism rotates the substrate before the gripper engages, positioning the orientation cut away from the gripping area in advance. This preliminary positioning action ensures that when the gripper subsequently grabs the substrate, the cut does not interfere with the gripping surfaces, thereby preventing improper holding or dropping.
2Productivity
If substrates are processed in vertical orientation, then cleaning and polishing processes are enabled, but rotation and gripping become difficult due to long orientation cuts on 150 mm substrates
Solution Approach 1:
The system dynamically adjusts substrate orientation by implementing a rotation mechanism that can reposition the substrate based on the position of the orientation cut. This dynamic adjustment allows the substrate to be rotated to optimal positions for both vertical processing and gripper engagement, making the operation easier despite the presence of long orientation cuts.
3Loss of information
If orientation cuts are made to indicate crystal and doping orientation, then substrate orientation information is provided, but the cuts interfere with substrate gripper operation
Solution Approach 1:
The system exploits the asymmetric position of the orientation cut by implementing a rotation mechanism that specifically positions the cut at locations that do not interfere with gripper engagement. The asymmetric nature of the cut is preserved for providing orientation information, while the rotation capability ensures it is positioned asymmetrically away from the gripping area during handling.
Data Source
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AI summary
A substrate position aligner includes a substrate holding assembly, a plurality of rollers, a rotation mechanism, and a sensor. The substrate holding assembly is configured to hold a substrate in a vertical orientation. The plurality of rollers include at least two idler rollers and a drive roller. Each roller has a point on its perimeter spaced on a common radius from a center of substrate rotation defined within the substrate holding assembly. The sensor is positioned approximately on the common radius and configured to detect the presence of an orientation cut in the substrate when the orientation cut is not orientated within a range between about - 44 degrees and about + 44 degrees from horizontal. A method of aligning a substrate having an orientation cut includes sensing a presence of the orientation cut when the orientation cut is not orientated within the above recited range.