Relay Optical System for Imprint Alignment Accuracy
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Solution Overview
Problem
The existing imprint apparatus has a limited detection numerical aperture (NA) for the through-the-mold detection system, leading to reduced alignment accuracy due to configurational constraints, which affects the precision of aligning the mold and substrate during the imprint process.
Innovation Solution
The introduction of a relay optical system that forms images of the alignment marks on the mold and substrate, allowing the detection system to increase its size and NA, thereby improving alignment accuracy by guiding light from these marks to a light-receiving element, while the illumination system is arranged to avoid interference with the detection system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the TTM detection system is arranged according to the Littrow arrangement to enable wafer alignment, then the detection system can function with an inclined arrangement relative to the illumination system, but the detection numerical aperture (NA) is limited due to configurational constraints, leading to reduced detection light amount and low alignment accuracy
Solution Approach 1:
A relay optical system is introduced as an intermediary component between the TTM detection system and the marks on the substrate and mold. This relay optical system includes lenses that form intermediate images of the marks, enabling the detection system to achieve a larger numerical aperture without directly interfering with the illumination system. The relay optical system mediates the optical path, allowing the detection system to be arranged inclined relative to the illumination system while still achieving high alignment accuracy through increased detection NA.
2Use of energy by stationary object
If the TTM detection system is arranged to get out of the way of the illumination system and illumination light flux, then the illumination system can function without interference, but the detection system must be arranged inclined relative to the optical axis of the illumination system, limiting the detection numerical aperture
Solution Approach 1:
The relay optical system extends the optical path in another dimension by creating intermediate images at different spatial locations. Instead of directly detecting light from the marks, the relay optical system forms intermediate images that can be detected at an inclined angle relative to the illumination axis. This dimensional extension of the optical path allows the detection system to operate in a different spatial plane, avoiding interference with the illumination light flux while maintaining high detection numerical aperture through the intermediate image formation process.
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 configuration enhances the alignment accuracy between the mold and substrate, leading to improved precision in overlaying patterns and increasing the yield rate of devices by ensuring accurate alignment and correction of misalignments during the imprint process.
Implementation Method 1
guide light reflected from the mark formed on the substrate and the mark formed on the mold to the light-receiving element
Implementation Method 2
The relay optical system is configured to form images of the light reflected from the mark formed on the substrate and the mark formed on the mold between the relay optical system and the detection system
Implementation Method 3
a detection system configured to illuminate a mark formed on the substrate and a mark formed on the mold
Implementation Method 4
guide light imaged by the relay optical system to the light-receiving element
Data Source
AI summary
An imprint apparatus, which is configured to transfer a pattern to an imprint material supplied on a substrate by using a mold having the pattern formed thereon, includes a light-receiving element, a detection system configured to illuminate a mark formed on the substrate and a mark formed on the mold, and guide light reflected from the mark formed on the substrate and the mark formed on the mold to the light-receiving element, and a relay optical system. The relay optical system is configured to form images of the light reflected from the mark formed on the substrate and the mark formed on the mold between the relay optical system and the detection system. The detection system is configured to guide the light image-formed by the relay optical system to the light-receiving element.