Newton's Ring Mold Deflection Measurement
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Solution Overview
Problem
Current methods for measuring the contact boundary between a mold and a substrate in imprint devices lack the necessary accuracy for optimizing imprint conditions, particularly in terms of mold deflection and gap control, which affects the quality of the imprint process.
Innovation Solution
A measurement method that involves pressing a mold onto a substrate with a resist in between, irradiating the substrate with light, and measuring Newton's rings to determine the peak positions and calculate the mold deflection, ensuring the gap between the mold and substrate is less than the optical distance λ/4, where λ is the wavelength of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to measure the contact boundary, then the measurement process is simple, but the measurement precision is insufficient for optimizing imprint conditions
Solution Approach 1:
The patent replaces mechanical contact sensing methods with optical measurement methods. By using light irradiation and Newton's ring observation, the system non-contactly measures the gap between mold and substrate, eliminating the need for complex mechanical sensors while achieving high measurement precision in the contact boundary region.
Solution Approach 2:
The patent utilizes optical interference patterns (Newton's rings) that manifest as concentric circular fringes. By analyzing the position and spacing of these optical fringes, the system determines the gap distance with high precision, converting optical information into measurable geometric data without mechanical contact.
2Manufacturing precision
If the gap between mold and substrate is increased for easier measurement, then the measurement becomes simpler, but the manufacturing precision of the imprint process deteriorates
Solution Approach 1:
The patent employs optical measurement to detect the gap in the contact boundary region where the gap is minimal. By using light interference patterns, the system can resolve very small gap distances (less than λ/4) without requiring mechanical sensors to physically probe the contact boundary, thus maintaining manufacturing precision while enabling accurate measurement.
Solution Approach 2:
The patent transitions from measuring gap in the vertical dimension (which is difficult when gap is small) to measuring the optical interference pattern in the lateral dimension. The Newton's ring fringe spacing provides a lateral optical signature that encodes the vertical gap information, enabling precise measurement of small gaps through optical field analysis.
3Measurement precision
If the resist height is increased to improve contact boundary definition, then the imprint pattern definition improves, but the optical distance for Newton's ring measurement increases reducing measurement accuracy
Solution Approach 1:
The patent focuses the measurement at the contact boundary region where the gap is minimal (less than λ/4), rather than measuring at the center where the resist height is greatest. By locally targeting the contact boundary where the optical distance is shortest, the system achieves high measurement precision for mold deflection while minimizing the optical path length, thus resolving the contradiction between resist height and measurement accuracy.
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 method allows for precise measurement of mold deflection and improved accuracy in determining the contact boundary, enhancing the filling performance and reducing defects by accurately controlling the curvature and pressure distribution during the imprint process.
Implementation Method 1
gas present between the substrate (the imprint material on the substrate) and the mold is extruded to the outside
Implementation Method 2
measuring peak positions of the Newton's rings in a contact boundary portion between the mold and the substrate
Implementation Method 3
irradiating the substrate with light via the mold... measuring Newton's rings
Data Source
AI summary
A measurement method of measuring deflection of a mold by measuring Newton's rings obtained by pressing the mold on a substrate with a resist interposed therebetween and irradiating the substrate with light via the mold includes: performing the pressing through the resist having a height less than an optical distance λ/4, λ being a wavelength of the light; measuring peak positions of the Newton's rings in a contact boundary portion between the mold and the substrate in a region in which a gap between the mold and the substrate is less than the optical distance λ/4; and calculating the deflection of the mold based on the peak positions.