Substrate Transfer Alignment Control Using Edge-Based Center Correction
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Solution Overview
Problem
Existing substrate transfer systems face challenges in accurately transferring substrates to target positions due to discrepancies between the center position of the substrate and the reference position of the holder.
Innovation Solution
A control method that detects the outer edge of the substrate, measures its center position using a preset adjustment value, corrects the target position based on displacement between the center position and a reference position, and controls the transfer mechanism to align the reference position with the corrected target position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transfer mechanism uses a preset reference position for substrate transfer, then the transfer process is simple and efficient, but the transfer accuracy deteriorates due to discrepancies between the substrate center position and holder reference position
Solution Approach 1:
The system performs preliminary detection of the substrate's outer edge and calculation of its center position before the transfer operation. This advance measurement allows the system to determine the displacement between the substrate center and holder reference position, and pre-correct the target position accordingly, ensuring accurate transfer without compromising efficiency
Solution Approach 2:
The system implements a feedback mechanism where the detected substrate center position is used to calculate and correct the target position. The displacement information feeds back into the control system, which then adjusts the transfer target dynamically, creating a closed-loop control that maintains both speed and accuracy
2Manufacturing precision
If the system detects and corrects the substrate center position, then the transfer accuracy is improved, but the process complexity increases due to additional detection and calculation steps
Solution Approach 1:
The outer edge detection unit serves multiple functions: it detects the substrate's outer edge, calculates the center position, determines displacement from the reference position, and provides data for target position correction. This multi-functionality reduces the need for separate dedicated components for each measurement and calculation task, thereby limiting the increase in overall system complexity
Solution Approach 2:
The system changes the parameter being controlled from a fixed reference position to a dynamically calculated target position based on detected substrate characteristics. By adjusting the target position parameter according to the measured displacement, the system achieves higher accuracy without requiring complex mechanical adjustments or additional physical components
Data Source
AI summary
An control method of a transfer mechanism is provided. The transfer mechanism transfers a substrate and has a holder for holding the substrate. In the control method, an outer edge of the substrate transferred by the transfer mechanism is detected and a center position of the substrate using a preset adjustment value corresponding to a path for transferring the substrate is measured. Further, in the control method, a target position is corrected based on the amount of displacement between the center position of the substrate and a preset reference position of the holder, and the transfer mechanism is controlled such that the reference position of the holder becomes the corrected target position.