Robot Misalignment Correction Using Beam Sensors
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Solution Overview
Problem
Dual-bladed SCARA robots experience misalignment issues due to differing amounts of droop when extending one or both end effectors, leading to positional errors and suboptimal substrate orientation in electronic device manufacturing systems.
Innovation Solution
A method and system that utilize flags and beam sensors to calibrate and correct misalignment by recording blocked and unblocked transition locations, determining position corrections for both single and dual-end effector extensions, ensuring precise alignment with process chamber centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dual-bladed robot extends end effectors for substrate transport, then productivity is improved, but misalignment occurs due to differing droop amounts
Solution Approach 1:
The system performs preliminary calibration by recording beam sensor transitions at multiple known robot configurations (both end effectors retracted, first extended, second extended, both extended). These pre-recorded data establish baseline measurements that are used to calculate correction factors before actual substrate processing begins, preventing misalignment rather than correcting it during operation
Solution Approach 2:
The system implements feedback by continuously monitoring beam sensor transitions during robot operation and comparing actual positions against the calibrated reference data. Correction factors are applied based on the difference between expected and actual sensor transitions, creating a closed-loop control system that maintains alignment precision during dynamic substrate transport operations
2Device complexity
If calibration is performed without accounting for different extension configurations, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The calibration process is segmented into distinct configuration stages (both retracted, first extended, second extended, both extended), with separate beam sensor transition recordings for each segment. This segmentation allows the system to capture configuration-specific droop characteristics without requiring a single overly complex calibration procedure, maintaining both precision and manageable complexity
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
The method improves substrate placement precision and processing quality by accounting for misalignment under different robot configurations, enhancing overall system throughput and reducing operational costs.
Implementation Method 1
recording measured positions in space where the first beam sensors are blocked and unblocked by the first flags, extending the robot in a second robot configuration with both of the first end effector and the second end effector extended and recording the measured positions in space where the first beam sensors are blocked and unblocked by the first flags and where the second beam sensors are blocked and unblocked by the second flags
Data Source
AI summary
Methods of correcting positional misalignment of blades in robots, such as dual-bladed robots, are described. The methods include, in one or more embodiments, a robot including moveable arms and an end effector attached to one of the moveable arms, a flag disposed on one of the moveable arms or the end effector, a chamber adapted to be serviced by the end effector, a beam sensor positioned at a distance from the chamber, and correcting misalignment of the end effector wherein the misalignment occurs between an initial linear center-finding location and the estimated center of the chamber. Systems of such electronic device calibration are also disclosed. Numerous other aspects are provided.