Relay Optical System for Imprint Alignment Accuracy
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Solution Overview
Problem
The existing imprint techniques face challenges in achieving accurate alignment between a mold and a substrate due to the restricted space for the through-the-mold detection system, which limits the numerical aperture and wavelength range of the TTM detection system, resulting in decreased alignment accuracy and yield.
Innovation Solution
The implementation of a relay optical system with a beam splitter and wavelength selection unit that guides and filters light to allow for a larger numerical aperture and wider wavelength range for the TTM detection system, preventing interference from the illumination optical system and ensuring high-accuracy die-by-die alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the TTM detection system is arranged above the mold to detect alignment marks, then alignment detection is enabled, but the space is restricted by the illumination optical system and head components, limiting the numerical aperture and detection accuracy
Solution Approach 1:
The patent introduces a relay optical system that redirects the detection optical path from a vertical arrangement (above the mold) to a horizontal arrangement (at the side of the mold). This dimensional change allows the TTM detection system to be positioned in the lateral direction, avoiding spatial conflict with the illumination optical system and head components while maintaining alignment detection functionality with improved numerical aperture
2Ease of operation
If the TTM detection system uses a Littrow configuration to detect substrate marks, then the system can operate with the available space, but the numerical aperture is limited and light irradiation range is restricted, decreasing alignment accuracy
Solution Approach 1:
The relay optical system changes the detection direction from vertical (through-the-mold) to horizontal (lateral detection), eliminating the need for Littrow configuration constraints. This allows the detection optical system to achieve larger numerical aperture and broader wavelength range without being limited by the tilt angle requirements of Littrow configuration
Solution Approach 2:
The relay optical system acts as an intermediary between the detection optical system and the substrate, transferring the detection function from a constrained vertical path to an unconstrained horizontal path. This intermediary system enables the detection optical system to achieve superior performance while maintaining compatibility with the existing illumination and molding operations
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 solution enhances the alignment accuracy between the mold and substrate, increasing the device yield by allowing for a larger numerical aperture and wider wavelength range, enabling precise pattern overlay and improved alignment robustness.
Implementation Method 1
a first optical member interposed between the illumination optical system and the detection optical system, and the mold, and configured to guide the first light from the illumination optical system and the second light from the detection optical system to the mold
Implementation Method 2
a second optical member interposed between the first optical member and the detection optical system, and configured to transmit the second light which is reflected by the at least one mark and travels toward the detection optical system through the first optical member, and block the first light which travels toward the detection optical system through the first optical member
Implementation Method 3
a detection optical system configured to irradiate, with second light, at least one mark out of a mark formed on the mold and a mark formed on the substrate, and detect the second light reflected by the at least one mark
Implementation Method 4
an illumination optical system configured to irradiate the imprint material with first light for curing the imprint material
Data Source
AI summary
The present invention provides an imprint apparatus which forms a pattern on an imprint material on a substrate by using a mold, including a first optical member interposed between an illumination optical system and a detection optical system, and a mold, and configured to guide a first light from the illumination optical system and a second light from the detection optical system to the mold, and a second optical member interposed between the first optical member and the detection optical system, and configured to transmit the second light which is reflected by a mark formed on the mold or a mark formed on the substrate and travels toward the detection optical system through the first optical member, and block the first light which travels toward the detection optical system through the first optical member.