Imprint Detection Device Segmented Illumination Angular Distribution
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Solution Overview
Problem
Existing imprint techniques face accuracy issues due to unwanted light beams scattering from the edges of positioning marks, which reduce the precision in measuring the position of marks in both the X and Y directions during the imprint process.
Innovation Solution
An illumination optical system with distinct angular distributions for each alignment mark direction is used, where the optical element forms specific illumination light beams for different portions of the surface, preventing unwanted light beams from interfering with the detection system, thereby enhancing positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image sensor is used to detect both X and Y alignment marks, then the device complexity is reduced, but the measurement precision deteriorates due to unwanted scattered light beams from mark edges interfering with the detection
Solution Approach 1:
The illumination optical system is segmented into multiple illumination regions, with each region dedicated to illuminating a specific alignment mark (X-direction or Y-direction). This segmentation allows independent optimization of illumination conditions for each mark type, preventing cross-interference from scattered light while maintaining a unified detection system.
Solution Approach 2:
Different angular distributions of illumination light are applied to different regions of the illumination optical system corresponding to different alignment marks. The first illumination region uses a first angular distribution optimized for X-direction marks, while the second illumination region uses a second angular distribution optimized for Y-direction marks, thereby improving measurement precision without increasing device complexity.
2Ease of operation
If alignment marks are illuminated with broad angular distributions, then the ease of operation is improved, but the measurement precision deteriorates due to increased scattered light beams reaching the image sensor
Solution Approach 1:
The illumination optical system provides different angular distributions at different illumination regions. Each region is configured with an angular distribution specifically optimized for its corresponding alignment mark orientation, achieving high measurement precision while maintaining ease of operation through automated illumination control.
Solution Approach 2:
The angular distribution parameter of the illumination light is changed depending on the region and the type of alignment mark being illuminated. By adjusting the angular distribution parameter locally for each illumination region, the system achieves optimal measurement precision for each mark type without requiring complex manual intervention.
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 effectively suppresses scattered light beams, improving the signal-to-noise ratio and enabling more accurate positioning of the mold and substrate relative to each other, leading to higher precision in pattern formation on the substrate.
Implementation Method 1
an optical element configured to form an illumination light beam for illuminating a first portion of a surface to be illuminated with a first angular distribution and a second illumination light beam for illuminating a second portion that is different from the first portion of the surface to be illuminated with a second angular distribution that is different from the first angular distribution
Implementation Method 2
a detection optical system configured to detect a light beam from a first alignment mark in the first portion of the surface to be illuminated with the first angular distribution and to detect a light beam from a second alignment mark in the second portion of the surface to be illuminated with the second angular distribution
Data Source
AI summary
A detection device includes an illumination optical system configured to illuminate a first alignment mark for detecting a position of an object in a first direction and a second alignment mark for detecting a position of the object in a second direction and a detection optical system configured to detect light beams from the alignment marks. The illumination optical system includes an optical element disposed at a position optically conjugate to a surface to be illuminated, and the optical element includes a region configured to form an illumination light beam for illuminating a first portion of the surface to be illuminated with a first angular distribution and a region configured to form an illumination light beam for illuminating a second portion of the surface to be illuminated with a second angular distribution.