Transfer Arm Edge Detection for Wafer Positioning
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Solution Overview
Problem
Existing positional deviation detection systems in semiconductor processing systems are inefficient due to fixed sensors that lengthen transfer routes, reduce throughput, and increase costs, and lack sufficient space for detection in loader chambers, leading to potential collisions and reliability issues.
Innovation Solution
A positional deviation detection apparatus integrated into transfer mechanisms with pivotable and bendable arm portions, featuring edge detection units with photoelectronic sensors along the arm portions to detect positional deviations without reducing throughput, allowing for real-time detection and compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If positional deviation detection sensors are provided in a fixed manner in the shared transfer chamber, then positional deviation can be detected, but the transfer route is lengthened and throughput is reduced
Solution Approach 1:
The patent applies the dynamics principle by moving the detection function from a fixed stationary sensor to a dynamic sensor integrated on the moving transfer arm. The sensor moves with the arm during transfer operations, enabling continuous detection without requiring the wafer to deviate from its transfer path, thus maintaining both detection capability and transfer efficiency
Solution Approach 2:
The transfer arm is given a dual function: it performs both the mechanical transfer function and the positional deviation detection function. By integrating the detection sensor on the transfer arm itself, the system eliminates the need for separate fixed detection infrastructure, resolving the contradiction between detection capability and transfer route efficiency
2Productivity
If positional deviation detection is carried out at occasional times during transferring operation, then throughput is maintained, but reliability is reduced due to potential undetected collisions
Solution Approach 1:
The patent implements continuous detection during the entire transfer operation by mounting the sensor on the moving arm. As the arm continuously moves the wafer from one chamber to another, the sensor continuously monitors positional deviation, ensuring no collision goes undetected while maintaining uninterrupted transfer operations
Solution Approach 2:
The detection sensor provides real-time feedback on wafer position during transfer. This continuous feedback enables immediate detection of any positional anomalies or collisions, allowing the system to maintain both high throughput through continuous operation and high reliability through constant monitoring
3Measurement precision
If more positional deviation detection sensors are provided in front of all process chambers, then detection coverage is improved, but cost increases
Solution Approach 1:
The patent extracts the detection function from the stationary chamber environment and relocates it to the mobile transfer arm. This eliminates the need for multiple fixed sensors in front of each process chamber, reducing system cost while maintaining comprehensive detection coverage through the single mobile sensor
Solution Approach 2:
A single detection sensor on the transfer arm serves all process chambers universally. As the arm moves between chambers, the same sensor provides detection coverage for all locations, eliminating the need for multiple dedicated sensors and reducing overall system cost
4Measurement precision
If positional deviation detection sensors are provided in the loader chamber, then detection can be performed there, but sufficient space is not available
Solution Approach 1:
The patent resolves the space constraint by using a dynamic sensor on the transfer arm that enters the loader chamber only when needed for transfer operations. The sensor utilizes the three-dimensional space of the loader chamber during arm movement rather than requiring dedicated horizontal space within the chamber
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
Enables precise and efficient detection of positional deviations without reducing throughput, reducing the risk of collisions and costs associated with additional sensors, while accommodating the limited space in loader chambers.
Implementation Method 1
edge detection unit that detects at least an edge of the object to be processed held by the distal end arm portion
Data Source
AI summary
In a positional deviation detection apparatus provided with a transfer mechanism where plural arm portions are connected pivotably and in series with each other, the transfer mechanism being adapted to hold and transfer an object to be processed with a distal end arm portion, there are provided an edge detection unit that detects at least an edge of the object to be detected held by the distal end arm portion, the edge detection unit being provided in an arm portion among the plural arm portions, except for the distal end arm portion; and a positional deviation detection portion that obtains positional deviation of the object to be processed, in accordance with a detected value of the edge detection unit.