Robot Arm Calibration for Accurate Load Lock Substrate Transfer
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Solution Overview
Problem
Electronics processing systems face challenges in accurately transferring substrates between stations due to system errors, misalignments, and positional inaccuracies, leading to incorrect orientation and positioning, which can result in reduced efficiency and increased risk of damage to components.
Innovation Solution
A method and system for calibrating transfer sequences between stations using a calibration object, which determines characteristic error values to correct for misalignments and positional errors, ensuring accurate alignment and orientation of substrates during transfer by recording and applying these values to aligner stations and robot arms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If robot arms transfer substrates between stations without calibration, then the transfer process is simple and fast, but positioning accuracy and orientation accuracy deteriorate due to system errors
Solution Approach 1:
The calibration process is performed in advance before normal substrate transfer operations. A calibration substrate is transferred through the same robot arms and stations to determine characteristic error values, which are then stored and applied during subsequent operations to compensate for positioning and orientation errors
Solution Approach 2:
A calibration substrate serves as a reference copy that replicates the properties of actual substrates. By measuring the orientation and position of this calibration substrate at known locations, the system creates a model of systematic errors that can be applied to correct all subsequent substrate transfers
2Manufacturing precision
If additional alignment operations are performed to correct positioning errors, then substrate placement accuracy improves, but system latency and processing time increase
Solution Approach 1:
The calibration substrate is transferred and measured in advance to determine all characteristic error values before normal production begins. These pre-calculated correction values are stored in memory and automatically applied during substrate transfer, eliminating the need for time-consuming real-time alignment operations
Solution Approach 2:
The system uses feedback from measuring the calibration substrate's actual position and orientation at known locations to automatically calculate and apply correction values. This closed-loop approach compensates for systematic errors without requiring manual intervention or additional alignment steps during production
3Measurement precision
If characteristic error values are determined and stored for each station, then transfer accuracy improves, but data storage requirements and system complexity increase
Solution Approach 1:
The calibration system determines and stores characteristic error values specifically for each individual station and transfer sequence combination. Each station has its own set of correction values tailored to its specific geometric and mechanical characteristics, allowing precise compensation without requiring excessive general calibration data
Data Source
AI summary
A first robot arm places a calibration object into a load lock that separates a factory interface from a transfer chamber using a first taught position. A second robot arm retrieves the calibration object from the load lock using a second taught position. A controller determines, using a sensor, a first offset amount between a calibration object center of the calibration object and a pocket center of the second robot arm. The controller determines a characteristic error value that represents a misalignment between the first taught position of the first robot arm and the second taught position of the second robot arm based on the first offset amount. The first robot arm or the second robot arm uses the first characteristic error value to compensate for the misalignment for objects transferred between the first robot arm and the second robot arm via the load lock.