Touch Auto-Calibration for Semiconductor Robot End Effector
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Solution Overview
Problem
Current end effector calibration techniques for semiconductor wafer handling systems are cumbersome, requiring bulky fixtures and can only be performed at atmospheric pressures and room temperatures, leading to inaccuracies in low-pressure and high-temperature semiconductor process chambers.
Innovation Solution
The implementation of a touch auto-calibration method that allows the end effector to automatically calibrate its position relative to an aligning base within the process chamber, using aligning surfaces to detect contact and calculate placement corrections, enabling accurate calibration at the actual production conditions without the need for fixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional calibration fixtures are used, then calibration can be performed, but the process becomes cumbersome and requires bulky equipment that cannot be used inside process chambers
Solution Approach 1:
The patent extracts the calibration function from external bulky fixtures and integrates it directly into the process chamber environment. The aligning base is mounted inside the process chamber on the pedestal, eliminating the need for external calibration equipment and allowing calibration to be performed in-situ under actual process conditions.
Solution Approach 2:
The patent introduces an aligning base with specific geometric features (aligning surfaces) as an intermediary element between the pedestal and end effector. This intermediary provides precise alignment references that enable accurate calibration without requiring complex external fixtures, resolving the contradiction between calibration accuracy and equipment complexity.
2Manufacturing precision
If calibration is performed at atmospheric pressure and room temperature, then calibration can be conducted externally, but accuracy deteriorates when used in low-pressure and high-temperature process chambers
Solution Approach 1:
The patent performs calibration actions preliminarily under the actual process conditions (low pressure, high temperature) rather than at standard atmospheric conditions. The aligning base and end effector are calibrated in-situ within the process chamber at the same pressure and temperature where they will operate, ensuring that thermal expansion and pressure effects are already accounted for, thereby maintaining high substrate placement accuracy.
Solution Approach 2:
The patent changes the calibration environment parameters to match the actual process conditions. By performing calibration at low pressure and high temperature rather than atmospheric pressure and room temperature, the system accounts for thermal expansion and pressure-induced dimensional changes, ensuring that the calibration remains accurate under operational conditions.
3Reliability
If manual calibration procedures are used, then calibration can be performed, but repeatability and consistency are poor
Solution Approach 1:
The patent implements a self-service calibration mechanism where the system automatically calibrates itself using the aligning base and end effector. The geometric features of the aligning base provide inherent alignment references that enable the system to determine the end effector's position and orientation automatically without requiring manual intervention, thereby achieving high repeatability and consistency.
Solution Approach 2:
The patent employs feedback mechanisms through sensors that detect the position and orientation of the end effector relative to the aligning base. This feedback information is used to automatically adjust and refine the calibration, ensuring high repeatability and consistency across multiple calibration cycles without manual intervention.
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 approach results in quick, accurate, and highly repeatable calibration of the end effector, ensuring consistent substrate placement and orientation, reducing defects and simplifying the calibration process by eliminating the need for complex setup and fixtures, while minimizing particle generation.
Implementation Method 1
measuring a torque value applied by a motor operable to move the end effector, detecting contact of all of the one or more aligning surfaces with the aligning base from the torque value
Data Source
AI summary
Methods and systems for the touch auto-calibration for robot placement of substrate in process modules are provided. Touch auto-calibration allows for the automatic calibration of robot end effector positioning with respect to an aligning base in a process module. Touch auto-calibration also allows for calibration of process modules at temperatures and pressures similar to the temperatures and pressures experienced during production. The end effector has one or more aligning surfaces configured to align it with the aligning base upon contact with the aligning base. After contact, the position of the end effector and the calibrated position of the end effector during a pick or place move can then be determined. In some implementations, the positioning of the end effector as it transfers a substrate during production is based on a placement coordinate with the placement correction applied.