Wafer Handling Robot Calibration Using Wafer Position Feedback
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Solution Overview
Problem
Manual calibration of wafer handling robots in semiconductor processing assemblies is time-consuming, strenuous, and requires expert knowledge, and existing methods may not accurately place wafers without causing damage after assembly maintenance.
Innovation Solution
An automated method for calibrating the position of a wafer handling robot relative to a wafer carrier using a wafer center finder and electronic controller, which repeatedly adjusts the movement path and entry angle until a set criterion is met, storing the calibrated positions for future use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration is performed, then calibration accuracy can be achieved, but calibration time and operational complexity increase significantly
Solution Approach 1:
The system performs self-calibration automatically without requiring external manual intervention. The wafer handling robot and wafer center finder work together in an automated feedback loop where the robot places wafers and the center finder determines their positions, continuously adjusting until calibration criteria are met, thereby eliminating the need for expert manual calibration while maintaining high accuracy
Solution Approach 2:
The calibration process incorporates a feedback mechanism where the wafer center finder continuously measures the actual wafer position after each robot placement, compares it with the target position, and provides this information back to the control system for automatic adjustment of the robot's movement parameters, enabling precise automated calibration
2Reliability
If manual calibration is performed, then calibration can be completed, but it requires expert knowledge and is strenuous
Solution Approach 1:
The system autonomously performs the entire calibration process without human intervention. The control system manages the robot movements, the wafer center finder performs measurements, and the system automatically determines when calibration criteria are satisfied, eliminating the need for expert operators and making the process equally easy to execute regardless of operator skill level
Solution Approach 2:
The patent replaces manual mechanical calibration operations with an automated system combining robotic manipulation and optical/electronic measurement. The wafer center finder uses non-contact measurement methods to determine wafer positions, substituting manual visual inspection and physical adjustment with automated sensing and control
3Productivity
If existing calibration methods are used after maintenance, then previous calibration data can be reused, but wafer placement accuracy deteriorates and damage may occur
Solution Approach 1:
The system performs a fresh automated calibration cycle immediately after maintenance when needed, rather than relying on outdated calibration data. This preliminary recalibration action ensures that the robot's movement parameters are updated to match the current physical state of the system, preventing wafer placement errors and damage while maintaining efficiency through automation
Solution Approach 2:
The calibration system is designed to be dynamically adaptable to changes in the system state. After maintenance activities that may alter the physical configuration, the system can automatically detect the need for recalibration and perform updated calibration cycles, ensuring continuous accuracy without requiring manual assessment of whether recalibration is needed
Data Source
AI summary
A method for automatically calibrating the position of a wafer handling robot relative to a wafer carrier. The method comprises providing a semiconductor processing assembly comprising the wafer carrier and the wafer handling robot having an end effector, placing a wafer on a wafer support surface of the end effector, moving the end effector to an end position adjacent the wafer carrier, determining a displacement of the wafer on the wafer support surface, repeating these steps until the magnitude of the displacement meets a set end criterion, and storing the latest used end position as a calibrated end position.