Substrate Transfer Position Correction Under Thermal Expansion
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Solution Overview
Problem
The substrate transfer mechanism experiences thermal expansion due to heat generated by power sources and high-temperature substrates, leading to positional deviations and reduced transfer accuracy.
Innovation Solution
A method of controlling the substrate transfer system involves correcting the target position based on measured positional deviations, thermal expansion at the measurement position, and thermal expansion at the target position, ensuring the reference position of the holder aligns with the corrected target position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal expansion of the transfer mechanism is not corrected, then the transfer mechanism operates simply without complex correction processes, but transfer accuracy degrades due to positional deviation caused by thermal expansion
Solution Approach 1:
The system performs preliminary thermal expansion correction calculations before substrate transfer. The correction amount is calculated based on thermal expansion coefficients and temperature changes, and this correction is applied to the target position in advance, ensuring accurate transfer despite thermal expansion effects
Solution Approach 2:
The system uses detection units to detect the actual position of the holder and substrate, compares it with the target position, and feeds back the positional deviation information. This feedback is used to adjust and correct the transfer position, forming a closed-loop control system that compensates for thermal expansion effects
2Measurement precision
If multiple detection units are used to detect positional deviation at different positions, then measurement accuracy improves, but the complexity of detecting and measuring increases
Solution Approach 1:
The detection system is divided into multiple independent detection units positioned at different locations along the transfer path. Each detection unit independently detects positional deviation at its specific position, allowing the system to obtain comprehensive positional information without requiring a single complex detection system
Solution Approach 2:
The system uses the detected positional deviation as an intermediary parameter to calculate the thermal expansion correction amount. The detection units don't directly provide the final correction value, but rather provide intermediate measurement data that is processed through thermal expansion calculations to generate the correction amount
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
This approach improves transfer accuracy by accounting for thermal displacement, reducing the deviation between the substrate's center position and the target position, thereby enhancing the precision of substrate placement.
Implementation Method 1
each part of the transfer mechanism thermally expands due to heat generated by a power source of the transfer mechanism or transfer of a substrate having a high temperature
Implementation Method 2
a measurement part configured to detect an outer periphery of the substrate being transferred by the transfer mechanism and measure a center position of the substrate
Data Source
AI summary
A method of controlling a substrate transfer system including a transfer mechanism having a holder, and a measurement part that detects an outer periphery of the substrate to measure a center position of the substrate, thereby transferring the substrate to a target position, includes: correcting the target position based on an amount of positional deviation between a reference position of the holder and the center position of the substrate, a first amount of thermal displacement of the reference position of the holder by thermal expansion of the transfer mechanism at a measurement position where the outer periphery of the substrate is detected, and a second amount of thermal displacement of the reference position of the holder by the thermal expansion of the transfer mechanism at the target position; and controlling the transfer mechanism such that the reference position of the holder becomes the corrected target position.