Substrate Alignment with Paired Sensors for Wedge Error Correction
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Solution Overview
Problem
Current methods for wedge error compensation in substrate alignment, particularly during bonding, are inefficient and unable to effectively handle non-transparent substrates, as they lack the necessary speed and accuracy, and often require assumptions about surface parallelism that may not be valid.
Innovation Solution
A device and method utilizing multiple internal and external distance sensors, arranged in pairs around a substrate holder, to measure distances and compensate for wedge errors by aligning the substrates with high accuracy, even for non-transparent substrates, by using interferometric measurements and adjustable sensor positions to ensure precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single-position distance measurement is used, then device complexity is reduced, but measurement precision and wedge error compensation accuracy deteriorate
Solution Approach 1:
The measurement system is segmented into multiple independent distance sensors positioned at different locations (at least three sensors arranged in a non-collinear fashion). Each sensor measures distance independently, and the results are combined to calculate wedge error, thereby improving measurement accuracy without requiring a single complex measurement system
Solution Approach 2:
The measurement approach transitions from single-point measurement to multi-point spatial measurement. By arranging sensors in a non-collinear configuration across two-dimensional space, the system captures wedge error information from multiple dimensions, enabling more accurate compensation while maintaining manageable device complexity
2Measurement precision
If interferometric measurement through substrate is used, then measurement precision is improved, but applicability to opaque substrates is limited
Solution Approach 1:
The distance measurement system is designed to function with both transparent and opaque substrates. By providing alternative measurement approaches (interferometric for transparent substrates, alternative methods for opaque substrates), the system achieves universal applicability across different substrate types while maintaining measurement precision
Solution Approach 2:
The measurement methodology is adjusted based on substrate properties. For opaque substrates, the system changes measurement parameters or approaches to accommodate the lack of optical transparency, thereby maintaining measurement precision across different material types
3Measurement precision
If wedge error compensation is performed slowly, then measurement accuracy can be maintained, but productivity and throughput deteriorate
Solution Approach 1:
The system performs preliminary measurements with multiple sensors to establish baseline distance information and calculate wedge error characteristics in advance. This preliminary action enables faster subsequent alignment operations while maintaining accuracy, as the computational framework is prepared beforehand
Solution Approach 2:
The patent replaces slow mechanical adjustment methods with automated sensor-based measurement and calculation systems. The use of electronic distance sensors and computational algorithms substitutes for time-consuming manual alignment procedures, thereby maintaining measurement precision while significantly improving processing throughput
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 significantly enhances the speed and accuracy of wedge error compensation, allowing for efficient alignment of substrates, including non-transparent ones, by using multiple sensors to measure and adjust distances, thereby improving throughput and measurement precision.
Implementation Method 1
The measurement is performed through one of the two transparent substrates, which are nanoembossing dies. The core idea of WO 2012 028 166 A1 is to compensate for the wedge error between the substrate surfaces on which the embossed structures are located.
Data Source
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AI summary
The invention relates to a device and a method for aligning substrates.