Lithography Mark Imaging for Precise Mold-Substrate Alignment
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Solution Overview
Problem
Existing imprint apparatuses face challenges in achieving accurate alignment between a mold and a substrate due to variations in optical characteristics and stray light affecting mark measurement accuracy, leading to degradation in alignment precision.
Innovation Solution
A lithography apparatus with a measurement unit that adjusts image capturing conditions for each region containing mold-side and substrate-side mark groups, allowing simultaneous capture and measurement of relative positions, and a control unit that aligns the original and substrate based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a mark group constituted of a plurality of kinds of marks is used to implement a wide detection range, then the detection range is improved, but the optical characteristic may be different between the marks which causes degradation in mark measurement accuracy
Solution Approach 1:
The patent divides the field of view into multiple regions, each corresponding to a specific mark or mark group. By segmenting the detection area, the system can apply different image capturing conditions (such as exposure time, gain, or illumination intensity) to each region, thereby optimizing the measurement accuracy for each mark type while maintaining a wide overall detection range.
Solution Approach 2:
The patent implements local optimization of image capturing conditions for each region containing different marks. Each region can have customized capturing parameters tailored to the specific optical characteristics of the marks in that region, ensuring that each mark is captured with optimal conditions for its specific optical properties.
2Productivity
If marks with different optical characteristics are simultaneously detected via the same optical system, then the detection efficiency is improved, but it is impossible to perform adjustment for obtaining an excellent image from each mark which degrades measurement accuracy
Solution Approach 1:
The patent dynamically adjusts image capturing conditions for different regions based on the specific requirements of each mark. The system can change parameters such as exposure time, gain, or illumination intensity for each region independently, allowing optimal image capture for multiple mark types with different optical characteristics while maintaining high detection efficiency through simultaneous measurement.
3Illumination intensity
If uneven light is used to illuminate the marks, then the illumination covers the entire field of view, but stray light from specific marks affects other marks and is included as noise in the detection signal
Solution Approach 1:
The patent segments the illumination field into multiple regions, each illuminated independently. By controlling illumination for each region separately, the system can provide sufficient light for each mark while preventing stray light from one mark from affecting other marks in different regions, thereby reducing noise in the detection signal.
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
Enhances alignment accuracy by optimizing image capturing conditions for each mark group, ensuring precise alignment and improved mark measurement, thereby improving the transfer of nanoscale patterns onto substrates.
Implementation Method 1
a mold-side mark provided in the mold and a substrate-side mark provided in the substrate are optically detected
Data Source
AI summary
A lithography apparatus that forms a pattern in a curable composition on a substrate using an original, including a measurement unit configured to obtain a mark image by simultaneously capturing a first mark group provided in the original and a second mark group provided in the substrate, which exist in one field of view, and measure a relative position between the first mark group and the second mark group, and a control unit configured to align the original and the substrate based on the relative position while measuring the relative position by the measurement unit, wherein the control unit adjusts an image capturing condition for each region which includes an image of each mark of the first mark group and the second mark group.