Exposure Head Position Calibration Using Beam Measurement Devices
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Solution Overview
Problem
In maskless exposure apparatuses for semiconductor or LCD fabrication, achieving precise exposure of a desired pattern on substrates is hindered by positional inaccuracies of exposure heads, leading to reduced exposure quality due to differences between actual and expected positions, as well as substrate distortions such as size, position, rotation, and warpage errors.
Innovation Solution
A method involving a stage with beam measurement devices to measure and correct the positions of exposure heads, using a reference position to map and adjust the positions of multiple exposure heads, and detecting substrate distortions using scopes to ensure precise alignment and uniform exposure, thereby correcting errors in rotation and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple exposure heads are used to scan the substrate, then exposure coverage and productivity are improved, but positional accuracy and exposure precision deteriorate due to differences between actual and expected positions of exposure heads
Solution Approach 1:
The patent applies preliminary action by measuring and recording the actual positions of all exposure heads before the exposure process begins. Position measurement values are obtained in advance by moving the stage to coincide beam measurement devices with each exposure head, and these pre-measured positions are stored as reference data. This preliminary positioning allows the control unit to compensate for positional deviations during actual exposure operations, thereby maintaining high exposure precision while using multiple exposure heads for broad coverage.
2Measurement precision
If the stage moves to measure positions of multiple exposure heads sequentially, then position measurement accuracy is improved, but measurement time and operation complexity increase
Solution Approach 1:
The patent applies segmentation by dividing the position measurement process into discrete, manageable steps. The stage moves sequentially to coincide beam measurement devices with each exposure head individually, measuring positions one at a time rather than attempting simultaneous measurement of all heads. This segmented approach, while time-consuming, ensures high measurement precision by systematically capturing the position of each exposure head relative to the stage, and the control unit stores these individual measurement values for later use in compensation calculations.
3Adaptability or versatility
If actual positions of exposure heads differ from expected positions, then device flexibility and adaptability are improved, but exposure quality and pattern accuracy deteriorate
Solution Approach 1:
The patent implements feedback by using the control unit to compare the pre-measured actual positions of exposure heads with their expected positions, calculate positional deviations, and then compensate for these deviations during the exposure process. The control unit stores the position measurement values and uses them to adjust the exposure positioning, creating a closed-loop system that adapts to actual hardware variations while maintaining pattern accuracy. This feedback mechanism allows the system to accommodate flexibility in exposure head positioning while ensuring manufacturing precision.
Data Source
AI summary
According to example embodiments, a method of operating an exposure apparatus including a stage having a plurality of beam measurement devices, and an exposure head unit having a first set of exposure heads and a second set of exposure heads includes measuring a position of a first exposure head of the first set of exposure heads by moving the stage to coincide a first beam measurement device of the plurality of beam measurement devices with the first exposure head, setting the measured position of the first exposure head as a reference position, and measuring positions of the second set of exposure heads with respect to the reference position.