Substrate Transfer Control With Real-Time Image Feedback
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Solution Overview
Problem
Existing substrate transfer systems face challenges in achieving high accuracy and stability due to mechanical errors, thermal expansion, and environmental changes, which affect the precision of substrate positioning and transfer in multi-chamber processing systems.
Innovation Solution
A substrate transfer unit equipped with a transfer mechanism having a shaft with a drive mechanism, a shaft angle detector, an imager, an image processor, and a transfer controller that performs real-time feedback control and correction based on image information to ensure precise positioning, using PID control and high-speed image processing to adjust the control parameters and reduce mechanical shaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional feedback control using shaft angle detection is used, then the control system is simple, but positioning accuracy deteriorates due to mechanical errors and thermal expansion
Solution Approach 1:
The patent replaces the conventional mechanical feedback control system (based on shaft angle detection) with an optical imaging system. The imager captures substrate position information optically, and the image processor calculates actual position data, substituting mechanical measurement with optical measurement to eliminate mechanical errors and thermal expansion effects
Solution Approach 2:
The patent introduces image processing as an intermediary between the imager and the control system. The image processor extracts substrate position information from captured images and provides corrected position data to the control unit, acting as a mediator that translates optical information into actionable control parameters
2Manufacturing precision
If real-time image processing is performed concurrently with feedback control, then positioning accuracy is improved, but processing time increases
Solution Approach 1:
The patent implements periodic action by performing image capture and processing at specific intervals during the substrate transfer process. The imager captures images at key moments, and the image processor processes these images periodically rather than continuously, maintaining accuracy while reducing overall processing time
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing the relationship between imager position and substrate position. The image processor uses pre-established coordinate transformations and position mapping data to quickly determine substrate position from images without requiring complex real-time calculations
Data Source
AI summary
A substrate transfer unit that transfers a substrate to a target transfer position includes a transfer mechanism having a portion where two arms are connected to each other by a shaft, an imager photographing the substrate, an image processor image-processing images, and a controller configured to perform feedback control of a drive mechanism such that when the substrate is transferred by a transfer mechanism, a shaft angle detected by a shaft angle detector reaches a target value, and perform correction of a feedback control based on image information obtained by image-processor. The transfer controller is further configured to perform the feedback control periodically, cause the imager and the image processor to perform the photographing and the image-processing in real time concurrently with the feedback control at least once for each feedback control, and perform the correction of the control operation whenever the feedback control is performed.