Wafer Transfer Robot Speed Control Based on Slip Detection
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Solution Overview
Problem
The existing substrate processing apparatuses face challenges in optimizing the operation speed of transfer robots due to slippage issues during acceleration and deceleration, as the frictional force varies with the state of the wafer, such as temperature, film, and flatness, making it difficult to improve transfer speed uniformly.
Innovation Solution
A substrate processing apparatus with a controller that detects the position of the wafer on the transfer robot's fork using sensor pairs, calculates the slippage amount, and adjusts the transfer speed accordingly, allowing for optimized operation based on the detected slippage, thereby optimizing the transfer speed of the robot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transfer robot operates at high speed, then productivity is improved, but slippage of the wafer on the fork increases due to acceleration and deceleration forces
Solution Approach 1:
The system uses sensor pairs to detect the position of the wafer on the fork during transfer operations. The detected position information is fed back to the controller, which then adjusts the transfer speed in real-time to prevent slippage while maintaining high productivity. This closed-loop feedback mechanism allows the system to operate at higher speeds without compromising wafer position stability.
Solution Approach 2:
The transfer speed is made dynamic rather than fixed. The controller adjusts the transfer speed based on real-time detection of wafer position and slippage conditions. This dynamic adaptation allows the system to optimize between speed and stability for each transfer operation, resolving the contradiction between high productivity and reliable wafer handling.
2Reliability
If vacuum attraction is applied to prevent slippage, then wafer position stability is improved, but the system becomes more complex and requires additional components
Solution Approach 1:
The system uses the existing fork structure and wafer holder to perform the slippage prevention function. By detecting wafer position and using control algorithms, the system makes the existing components serve the dual purpose of transfer and slippage prevention, avoiding the need for additional vacuum attraction components and reducing system complexity.
3Reliability
If transfer speed is reduced to prevent slippage, then wafer position stability is improved, but productivity decreases
Solution Approach 1:
Real-time detection of wafer position provides feedback that allows the controller to maintain optimal transfer speed without slippage. The system only reduces speed when actually needed based on detected conditions, rather than operating at uniformly reduced speeds, thus maintaining high productivity while ensuring wafer stability.
Solution Approach 2:
The transfer speed parameter is dynamically changed based on detected wafer position and slippage conditions. This allows the system to operate at high speeds during stable conditions and temporarily reduce speed only when slippage is detected, optimizing both productivity and reliability through parameter adaptation.
Data Source
AI summary
There is provided a substrate processing apparatus comprising: a first placement chamber; a second placement chamber; a transfer robot; and a controller. The controller is configured to: a) control the apparatus such that a position of an object on a fork of the transfer robot is detected as a first position when unloading the object from the first placement chamber; b) control the apparatus such that the object is unloaded from the first placement chamber to a standby position of the first placement chamber and then transferred to a standby position of the second placement chamber; c) control the apparatus such that a position of the object on the fork is detected as a second position when loading the object to the second placement chamber; and d) control the apparatus such that a transfer speed of b) is controlled based on the first position and the second position.