Optical Transfer Detection for Multi-Fork Substrate Handling
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in accurately detecting the transfer state of multiple substrates across multiple stages due to overlapping fork positions, which complicates determining which fork holds a substrate during transfer.
Innovation Solution
The implementation of an optical sensor system that projects horizontal light beams across the transfer path, allowing the controller to determine the presence and state of substrates on multiple forks by measuring light blockage, thereby distinguishing between forks and accurately tracking substrate transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor projects a light beam perpendicular to the transfer surface to detect substrate passage, then substrate transfer detection is enabled, but accurate detection of multiple substrates on multiple forks becomes difficult due to overlapping fork positions
Solution Approach 1:
The detection system is segmented into multiple optical sensors, each assigned to detect specific forks at different positions. Instead of using a single sensor that struggles to distinguish between overlapping forks, the system divides the detection task across multiple sensors, with each sensor responsible for a specific spatial zone or fork, thereby resolving the ambiguity in detecting which fork holds which substrate
Solution Approach 2:
The detection approach transitions from a single-dimensional perpendicular light beam projection to a multi-dimensional detection scheme using multiple sensors positioned at different locations and angles. This spatial distribution of sensors across multiple dimensions enables the system to differentiate between forks that overlap when viewed from a single perspective, allowing accurate tracking of multiple substrates simultaneously
2Productivity
If multiple substrates are transferred to multiple stages simultaneously, then productivity is improved, but the ability to accurately determine which fork holds which substrate deteriorates
Solution Approach 1:
The system implements a feedback mechanism where multiple optical sensors continuously monitor the positions of substrates and forks, providing real-time detection data to the control unit. The control unit processes this feedback information to dynamically determine and track which fork holds which substrate at each stage, enabling accurate substrate-fork association even during simultaneous multi-stage transfers that would otherwise cause detection ambiguity
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 method enables precise detection of substrate transfer states, ensuring accurate tracking and preventing errors in substrate handling across multiple stages within the substrate processing apparatus.
Implementation Method 1
projecting a light beam having a horizontal optical axis parallel to the opening to a position through which the substrates held by the plurality of substrate holders pass; and determining at least one of a state of the substrates on the substrate holders and a state of the transfer arm, in response to a detection result of the light beam projected from the optical sensor
Data Source
AI summary
Provided is a transfer detection method for use in a substrate processing apparatus including a transfer arm, which has a plurality of substrate holders and is configured to transfer a plurality of substrates to a plurality of stages between a first chamber and a second chamber adjacent to the first chamber by using the plurality of substrate holders, and an optical sensor provided in a vicinity of an opening via which the first and second chambers are in communication with each other, the method including: projecting a light beam having a horizontal optical axis parallel to the opening to a position through which the substrates held by the plurality of substrate holders pass; and determining at least one of a state of the substrates on the substrate holders and a state of the transfer arm, in response to a detection result of the light beam projected from the optical sensor.