Wafer Aligner with Vertical Sensor Array for Multi-Wafer Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor transfer systems using multi-hand transfer robots are unable to precisely place wafers at their reference positions due to limitations in aligner devices, which can only determine positional misalignment for a single wafer, hindering the reduction of transfer takt time.
Innovation Solution
An aligner device with vertically aligned hand members, a workpiece lifting mechanism, and sensors to capture the outline shape of wafers, calculating and correcting positional misalignment in X, Y, and θ directions, allowing simultaneous detection and correction of multiple wafers' positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-hand transfer robot is used to transfer multiple wafers simultaneously, then the transfer takt time is reduced, but the precision of placing wafers at their reference positions deteriorates
Solution Approach 1:
The aligner device performs preliminary alignment of multiple wafers before they are transferred to the processing chamber. The sensor detects the outline shapes of wafers on the robot hand, and the positional misalignment calculating unit calculates misalignment amounts in advance, allowing the transfer robot to correct positions before final placement, thus maintaining both high speed and high precision
Solution Approach 2:
The system incorporates a feedback mechanism where the sensor detects the actual position of wafers, the positional misalignment calculating unit computes the deviation from reference positions, and the transfer robot uses this feedback information to correct positioning errors dynamically during the transfer process, ensuring precise placement while maintaining rapid transfer rates
2Measurement precision
If a conventional aligner device is used to determine misalignment of a single wafer, then the measurement precision is maintained, but the productivity is reduced due to inability to process multiple wafers simultaneously
Solution Approach 1:
The aligner device is segmented into multiple independent detection units, with each sensor in the vertical array capable of detecting the outline shape of a specific wafer. This segmentation allows the system to process multiple wafers simultaneously while maintaining the high measurement precision of individual wafer alignment through dedicated detection and calculation for each wafer
3Productivity
If the robot hand holds multiple wafers vertically aligned, then the transfer efficiency is improved, but the complexity of detecting and measuring positional misalignment of all wafers increases
Solution Approach 1:
The system adds a vertical dimension to the detection arrangement by positioning sensors at different heights (vertically spaced apart) to detect multiple wafers simultaneously. This dimensional change allows the sensor to capture outline shapes of multiple wafers in a single detection cycle, reducing the complexity of coordinating multiple detection operations while maintaining high transfer efficiency
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
Significantly reduces transfer takt time by enabling precise alignment and correction of multiple wafers, improving the efficiency of semiconductor processes.
Implementation Method 1
each of the plurality of sensors has a sensor surface that faces downward to capture an outline shape of a planar workpiece
Data Source
AI summary
An aligner device includes a robot hand, a lifting mechanism, sensors, a misalignment calculating unit, an x-y misalignment correcting unit, and a θ misalignment correcting unit. The robot hand includes vertically aligned hand members each configured to hold a planar workpiece. The lifting mechanism moves planar workpieces transported by the robot hand up from and down to the hand members, respectively. Each of the sensors, vertically spaced apart from each other, has a downward sensor surface to capture the outline of a planar workpiece brought close to the sensor surface by the workpiece lifting mechanism. The misalignment calculating unit calculates, by using the images of the captured outline shapes of the planar workpieces, an amount of positional misalignment of each planar workpiece with a reference position in X, Y and θ directions. The X-Y misalignment correcting unit corrects the misalignment of each planar workpiece in the X and Y directions based on the amount of X-Y direction misalignment calculated by the misalignment calculating unit. The θ misalignment correcting unit corrects the misalignment of each planar workpiece in the θ direction based on the amount of θ misalignment of the planar workpiece.