Imprint Apparatus Mesa Light Limiter for Mark Image Contrast
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Solution Overview
Problem
The degradation of mark image quality in the imprint technique due to light interference from the mesa structure and light-shielding films in molds, which affects alignment detection and pattern formation in semiconductor devices.
Innovation Solution
An imprint apparatus with an alignment optical system that includes a limiter to restrict the incidence of illumination light to the mesa's side, ridge line, and outer regions, preventing light interference and enhancing mark image contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mark is illuminated for alignment detection, then the mark image can be detected, but light from the mesa side and light-shielding film reduces mark image contrast
Solution Approach 1:
The patent extracts and removes the harmful light components by introducing a light-shielding film that selectively blocks reflected light from the mesa side and light-shielding film portions outside the shot region, while allowing illumination light to reach the mark for alignment detection. This separates the useful light (illumination light for mark detection) from harmful light (reflected/scattered light reducing contrast).
Solution Approach 2:
The patent introduces a light-shielding film as an intermediary element that mediates between the illumination light source and the mark. This film selectively transmits illumination light to the mark while blocking harmful reflected and scattered light from the mesa structure and light-shielding film portions, thereby improving mark image contrast without preventing alignment detection.
2Manufacturing precision
If a light-shielding film is provided to prevent irradiation of areas outside the shot region, then pattern formation precision is improved, but illumination light is reflected by the light-shielding film during alignment detection
Solution Approach 1:
The patent extracts and removes the harmful reflected light components by introducing an additional light-shielding film configured to block reflected light from the light-shielding film portions outside the shot region during alignment detection, while maintaining the light-shielding function for pattern formation precision.
Solution Approach 2:
The patent applies different optical properties to different regions: the light-shielding film portions outside the shot region are designed to block reflected light during alignment detection, while the pattern region maintains light transmission for curing. This local differentiation resolves the contradiction between pattern formation precision and alignment detection quality.
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 effectively suppresses light interference, improving the quality of mark images and enabling accurate alignment and pattern formation on substrates, thereby enhancing the precision and reliability of the imprint process.
Implementation Method 1
the mark on the mold and the mark on the shot region are illuminated with illumination light, and a mark image formed by light from these marks can be detected
Implementation Method 2
the illumination system includes a limiter configured to limit incidence of the illumination light to a side of the mesa, a ridge line of the mesa, and an outer region of the side
Implementation Method 3
a mold on which a pattern is formed is brought into contact with an imprint material arranged on a substrate, and the imprint material is cured by irradiation with curing energy, thereby forming a pattern made of a cured product of the imprint material
Data Source
AI summary
An imprint apparatus for forming a pattern of an imprint material on a substrate using a mold having a mesa including a pattern region where a pattern and a mark are formed. The apparatus includes an alignment optical system which includes an illumination system configured to illuminate the mark with illumination light and a detecting system configured to detect an image of the mark illuminated by the illumination system. The illumination system includes a limiter configured to limit incidence of the illumination light to a side of the mesa, a ridge line of the mesa, and an outer region of the side.