Moiré Alignment Mark for Semiconductor Imprinting
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Solution Overview
Problem
Current alignment techniques in semiconductor manufacturing, such as imprint processing, face limitations in precision and efficiency due to the low degree of freedom in arranging alignment marks, leading to unnecessary areas and reduced effectiveness in detecting positional deviations between templates and wafers.
Innovation Solution
The implementation of a moiré-based alignment mark system that includes a set of patterns on both the template and the wafer, utilizing overlapping moiré marks with specific pitch lengths and duty ratios to enhance precision and reduce the area required for alignment, allowing for more flexible arrangement and improved detection of positional deviations.
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 areas are generated
Solution Approach 1:
The patent changes the fundamental parameters of alignment marks from conventional single-layer opaque patterns to multi-layer patterns with specific transparency ratios (first transparency ratio for the first pattern, second transparency ratio for the second pattern). This parameter change enables the alignment marks to be arranged with higher degree of freedom while reducing useless areas, as the transparent and semi-transparent regions can be optimally positioned without completely blocking underlying circuit patterns.
Solution Approach 2:
The alignment mark structure uses composite material principles by combining multiple layers with different optical properties (fully transparent region, semi-transparent region, opaque region) in a single alignment mark structure. This composite approach allows the alignment mark to perform its alignment function while minimizing the impact on underlying circuit patterns and reducing useless areas.
2Measurement precision
If alignment marks are provided on the original and workpiece, then alignment can be performed, but precision is limited due to low degree of freedom in arrangement
Solution Approach 1:
The patent introduces specific transparency parameters (first transparency ratio and second transparency ratio) to enhance alignment precision. By controlling the transparency ratios of different regions, the alignment marks provide clearer contrast and more precise detection signals while maintaining flexibility in arrangement. The semi-transparent region specifically enhances detection precision by allowing partial light transmission that creates distinct optical signals.
Solution Approach 2:
The patent replaces conventional mechanical/optical alignment mark structures with a photonic-based system that uses light transmission and transparency ratios to achieve alignment. This substitution of the alignment mechanism with optical property-based detection enables higher precision measurement while providing greater freedom in mark arrangement.
3Productivity
If conventional alignment marks are used, then alignment process can be completed, but efficiency is reduced due to unnecessary areas
Solution Approach 1:
By changing the transparency parameters of alignment marks, the patent reduces the effective area required for alignment marks while maintaining their functionality. The semi-transparent and transparent regions allow for more compact alignment mark designs that occupy less useless area, thereby increasing the effective manufacturing area and improving overall production 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
This approach enables highly precise alignment with reduced unnecessary areas, enhancing the degree of freedom in alignment mark arrangement and improving the detection of positional deviations, thereby improving the efficiency of semiconductor manufacturing processes.
Implementation Method 1
utilizing overlapping moiré marks with specific pitch lengths and duty ratios to enhance precision and reduce the area required for alignment
Data Source
AI summary
In an alignment mark of an embodiment, a first pattern includes a first portion and a second portion, a second pattern includes a third portion and a fourth portion, the first portion and the third portion partially overlap each other, the second portion and the fourth portion partially overlap each other, a pitch length of each structural periods of the first portion and the third portion are equal within 1.2 times, a pitch length of each structural periods of the second portion and the fourth portion are equal within 1.2 times, a duty ratio of each of the first and third portions is 1:1, and a duty ratio of the second portion is D:2, and D is an integer of two or more, the duty ratio being a ratio between a light-shielding portion and a light-transmitting portion.