Imprint Apparatus Digital Mirror Device Overlay Accuracy
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Solution Overview
Problem
Existing imprint techniques face challenges in maintaining overlay accuracy due to deformation of molds and substrate shape mismatches, particularly when using materials like quartz, which affects the precision of pattern formation in micropatterning processes.
Innovation Solution
An imprint apparatus equipped with a digital mirror device that measures and controls light distribution to heat the substrate, allowing for precise shape correction of the pattern region to match the mold's shape, thereby enhancing overlay accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a digital mirror device is used to heat the substrate for shape correction, then overlay accuracy is improved, but light amount unevenness and reflectance differences cause deviations from desired heat input
Solution Approach 1:
The patent implements a feedback mechanism where a measurement unit measures the actual light amount for each segment of the digital mirror device, and a control unit adjusts the mirror element control signals based on these measurements. This closed-loop feedback system compensates for light amount unevenness and reflectance differences, ensuring accurate heat input distribution to the substrate for precise shape correction and overlay accuracy.
Solution Approach 2:
The patent divides the digital mirror device into multiple segments and independently controls the light amount for each segment by adjusting mirror element angles or positions. This parameter change approach allows compensating for local variations in reflectance and light distribution, enabling precise control of heat input distribution across the substrate surface.
2Manufacturing precision
If the mold is deformed to match substrate pattern shape, then overlay accuracy is improved, but Poisson's ratio causes non-linear deformation making trapezoidal shaping difficult
Solution Approach 1:
Instead of deforming the mold to match the substrate pattern, the patent inverts the approach by heating and deforming the substrate to match the mold pattern. This avoids the Poisson's ratio deformation issues of the mold material (quartz) and enables accurate trapezoidal and other complex shape corrections on the substrate side, achieving high overlay accuracy.
Solution Approach 2:
The patent utilizes thermal expansion of the substrate by irradiating it with light absorbed as heat. By controlling the spatial distribution of light intensity across the substrate, localized thermal expansion occurs, deforming the substrate pattern shape to match the mold pattern. This thermal deformation method overcomes the limitations of mechanical mold deformation due to Poisson's ratio.
3Manufacturing precision
If light irradiation is used to heat the substrate for shape correction, then overlay accuracy is improved, but reflectance difference and light amount unevenness reduce heating precision
Solution Approach 1:
The patent divides the digital mirror device into multiple segments, with each segment controlling a specific region of the substrate. By measuring and independently adjusting the light amount for each segment, the system compensates for spatial variations in reflectance and light distribution, achieving uniform and precise heat input across the entire substrate surface for accurate pattern shape matching.
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
The apparatus achieves improved overlay accuracy by accurately matching the substrate's pattern shape to the mold's shape, even with materials that exhibit deformation, such as quartz, ensuring high precision in micropatterning processes.
Implementation Method 1
a digital mirror device including two-dimensionally arrayed mirror elements and configured to irradiate the substrate with light reflected by the mirror elements
Implementation Method 2
irradiating the substrate with light, which has a wavelength that does not cure an imprint material, to cause the substrate to undergo heat deformation by the absorbed heat
Implementation Method 3
a measurement unit configured to measure, for each of a plurality of segments obtained by dividing a region in which the mirror elements are arrayed, a light amount of light emitted from each segment
Data Source
AI summary
The present invention provides an imprint apparatus that performs an imprint process of forming a pattern of an imprint material on a processing target region on a substrate by using a mold, including a digital mirror device including two-dimensionally arrayed mirror elements and configured to irradiate the substrate with light reflected by the mirror elements, a measurement unit configured to measure, for each of a plurality of segments obtained by dividing a region in which the mirror elements are arrayed so as to include a plurality of the mirror elements, a light amount of light emitted from each segment, and a control unit configured to control the mirror elements included in each segment based on a measurement result of the measurement unit.