Moiré Phase Shift Position Detection for Imprint Alignment
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Solution Overview
Problem
In imprint technology, precise alignment between molds and substrates is challenging due to deviations in the positional relationship between circuit patterns and alignment marks, leading to errors in pattern transfer, especially with the increasing complexity of semiconductor processes requiring sub-100 nm alignment accuracy.
Innovation Solution
A position detection apparatus that utilizes moiré patterns formed by overlapping diffraction gratings to determine relative positioning, performing periodic analysis of luminance distribution to obtain phase measurement values and adjust for phase shifts, ensuring accurate alignment by shifting phase measurement values outside predetermined discontinuous ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moiré patterns are used for position detection, then measurement precision is improved, but device complexity increases due to the need for phase analysis and correction mechanisms
Solution Approach 1:
The patent replaces direct mechanical or optical measurement systems with a moiré pattern-based detection system. By overlapping diffraction gratings from the mold and substrate to generate moiré patterns, the system achieves high-precision position detection through optical interference rather than direct mechanical measurement, thereby improving measurement precision while using a sophisticated but manageable detection approach
Solution Approach 2:
The patent changes the parameter being measured from direct physical displacement to the phase information of moiré patterns. By analyzing phase shifts in the moiré pattern luminance distribution, the system achieves sub-pixel resolution and high measurement precision. The phase information serves as an intermediate parameter that amplifies small positional changes into detectable optical patterns
2Ease of operation
If alignment marks are used for positioning, then ease of operation is improved, but manufacturing precision deteriorates due to deviations in the positional relationship between circuit patterns and alignment marks
Solution Approach 1:
The patent introduces moiré patterns as an intermediary between the alignment marks and the final positioning determination. Instead of directly using alignment mark positions, the system uses the interference pattern formed by overlapping diffraction gratings as a mediator to detect relative positioning. This intermediary approach allows the system to detect deviations caused by misalignment between circuit patterns and alignment marks, thereby improving manufacturing precision while maintaining the operational simplicity of using alignment marks
Solution Approach 2:
The patent implements a feedback mechanism where the moiré pattern phase information is used to detect and correct positioning deviations. By continuously monitoring the phase shifts in the moiré patterns during the alignment process, the system provides real-time feedback on the relative positioning between mold and substrate, allowing for precise adjustments to achieve accurate circuit pattern alignment
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 enhances the accuracy of position detection and pattern transfer by minimizing alignment errors, enabling precise alignment even with low-resolution detection systems and addressing deviations in circuit pattern alignment.
Implementation Method 1
an image of a moiré that occurs due to a first diffraction grating having a grating pattern arranged in a first direction and a second diffraction grating having a grating pattern arranged in the first direction at a different pitch to the first diffraction grating overlapping
Implementation Method 2
obtain an image of a moiré that occurs due to a first diffraction grating having a grating pattern arranged in a first direction and a second diffraction grating having a grating pattern arranged in the first direction at a different pitch to the first diffraction grating overlapping
Data Source
AI summary
A position detection apparatus comprises an obtaining unit that obtains an image of a moiré that occurs due to first and second diffraction gratings overlapping; and a processor configured to perform a periodic analysis of a luminance distribution of the obtained image of the moiré, obtain a phase measurement value of the luminance distribution, and obtain a relative positioning between the first and second diffraction gratings, wherein the processor determines a phase shift amount for making the obtained phase measurement value be a value outside of a predetermined range including a discontinuous part of the phase, and performs a phase shift to shift the obtained phase measurement value by the determined phase shift amount, and obtains the relative positioning based on the phase-shifted phase measurement value.