Robot End-Effector Position Estimation for Substrate Placement
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Solution Overview
Problem
Semiconductor processing robots face inaccuracies in substrate placement due to mechanical imperfections like structural flexibilities and temperature-induced thermal deformations, which affect the accuracy of Adaptive Placement Systems (APS) by causing discrepancies between calculated and actual end-effector positions.
Innovation Solution
A method and apparatus that estimate deflection in robot members during movement, determine calculated end-effector coordinates, and adjust robot movement to accurately place substrates, incorporating position capture mechanisms that account for flexible dynamics and thermal deformations, using estimation algorithms and auxiliary sensors to correct for mechanical imperfections and thermal effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the robot uses pre-programmed geometry knowledge to calculate end effector position, then the calculation is simple and fast, but thermal deformation and mechanical flexibilities cause inaccuracy in the position calculation
Solution Approach 1:
The system uses sensors to detect the actual position of the end effector and feeds this information back to the controller. The controller then adjusts the robot's motion commands based on the difference between the desired and actual positions, compensating for thermal deformation and mechanical flexibilities dynamically during operation.
Solution Approach 2:
The patent replaces reliance on rigid mechanical geometry with a software-based dynamic compensation system. Instead of depending on fixed mechanical relationships that degrade under thermal and mechanical loads, the system uses real-time sensor data and control algorithms to calculate and adjust end effector position, substituting mechanical precision with computational correction.
2Manufacturing precision
If external sensors are used to detect substrate edges during robot motion, then substrate placement accuracy is improved, but the system complexity and cost increase
Solution Approach 1:
The system integrates multiple functions into the existing robot structure. The same robot controller that manages motion also processes sensor data for adaptive placement. Existing robot components serve dual purposes: mechanical manipulation and sensor mounting, reducing overall system complexity while maintaining high placement accuracy.
Solution Approach 2:
The robot system performs its own calibration and correction using integrated sensors. The adaptive placement system uses the robot's own motion data combined with sensor measurements to self-correct positioning errors, eliminating the need for separate complex calibration systems or external reference equipment.
3Adaptability or versatility
If the robot operates in environments with temperature changes, then the robot can maintain operational flexibility, but thermal expansion and contraction cause inaccuracy in position calculation
Solution Approach 1:
The system dynamically changes the parameters used for position calculation based on operating conditions. Instead of using fixed geometric parameters that become inaccurate under thermal stress, the system adjusts position calculations using real-time temperature data and measured actual positions, allowing accurate operation across varying temperature conditions while maintaining flexibility.
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
Improves the accuracy of substrate placement by accounting for structural flexibilities and thermal deformations, enhancing the precision of Adaptive Placement Systems in semiconductor processing robots.
Implementation Method 1
a motor of the robot generates a torque in accordance with the command torque
Data Source
AI summary
A method including, based at least partially upon a command transmission to at least one motor of a robot, estimating deflection for at least one member of the robot during movement of the robot; based at least partially upon the estimated deflection, determining calculated end effector coordinates for an end effector of the robot; and based at least partially upon the calculated end effector coordinates, adjusting movement of the robot for placing a substrate, located on the robot, at a desired location.