Semiconductor Alignment Mark Using Moiré Patterns
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Solution Overview
Problem
Current alignment techniques in semiconductor manufacturing, such as imprint processing, face limitations due to low flexibility in arranging alignment marks, leading to unnecessary area usage and reduced degrees of freedom in pattern arrangement.
Innovation Solution
The implementation of a combination of periodic structures on alignment marks on both the template and the substrate, utilizing moiré patterns for precise alignment, which allows for orthogonal directions and varying periodic intervals to enhance alignment accuracy and reduce the area occupied by alignment marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If alignment marks are provided on the original and workpiece using conventional methods, then alignment can be performed, but the degree of freedom in arrangement is low and useless area is generated
Solution Approach 1:
The patent introduces moiré patterns created by overlapping periodic structures at different orientations (X-direction and Y-direction marks). This transforms the alignment mechanism from simple linear marking to two-dimensional pattern interference, enabling precise alignment in multiple directions simultaneously without increasing the footprint of individual alignment marks.
Solution Approach 2:
The patent combines multiple alignment functions into a single integrated moiré pattern system. By superimposing periodic structures with different orientations on both the original and workpiece, the system achieves alignment verification in both X and Y directions using a unified approach, reducing the total area required compared to separate alignment mark systems for each direction.
2Measurement precision
If conventional alignment marks are used, then alignment process can be completed, but measurement precision is insufficient for highly precise alignment requirements
Solution Approach 1:
The patent introduces moiré patterns as an intermediary measurement mechanism. Instead of directly measuring the position of alignment marks, the system uses the interference pattern (moiré fringes) generated by overlapping periodic structures as a magnified indicator of misalignment. This intermediary approach amplifies small displacement errors, making them easily detectable and measurable with standard optical systems.
Solution Approach 2:
The patent changes the measurement parameter from direct positional measurement to optical interference pattern analysis. By transforming the alignment verification into a optical phenomenon (moiré effect), the system achieves high measurement precision through changes in the observed interference pattern rather than relying on direct dimensional measurement of alignment marks.
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 enables highly precise alignment with a magnified displacement detection, reducing the block area required for alignment marks and increasing the degree of freedom in their arrangement, thereby optimizing the use of space and improving manufacturing efficiency.
Implementation Method 1
utilizing moiré patterns for precise alignment, which allows for orthogonal directions and varying periodic intervals to enhance alignment accuracy
Data Source
AI summary
In an alignment mark of an embodiment, a first pattern has a periodic structure in a first direction on a surface of an original or a surface of a substrate and extends in a second direction, and a second pattern has a periodic structure in a third direction on the surface of the original or the surface of the substrate and extends in a fourth direction. The first direction and the third direction are parallel to each other. A period in the first direction of the periodic structure of the first pattern is equal to a period in the third direction of the periodic structure of the second pattern. At least one of the first pattern and the second pattern has a periodic structure in a fifth direction orthogonal to the first direction and the third direction on the surface of the original or the surface of the substrate. At least one of the second direction and the fourth direction is oblique with respect to the fifth direction.