Imprint Leveling Unit With Segmented Links for Uniform Pressure
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Solution Overview
Problem
Existing leveling units for nano imprint lithography face challenges in maintaining parallelism between a wafer and a stamp, leading to uneven pressure distribution and potential damage due to excessive stress concentration on flexure hinges during high-load thermal imprint processes.
Innovation Solution
A leveling unit comprising a base plate, a moving plate, and a plurality of link parts that connect the base plate to the moving plate, allowing for elastic transformation and adjustment of the moving plate's inclination to maintain parallelism between the wafer and the stamp, with load sensors to ensure uniform pressure distribution and prevent damage from stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive mechanism using a flexure hinge is used to maintain parallel between stamp and wafer, then additional actuators are unnecessary, but excessive stress may be applied to a specific flexure hinge causing damage or fracture
Solution Approach 1:
The leveling unit is divided into multiple independent link assemblies (first, second, third, and fourth link assemblies) distributed around the reference plane. Each link assembly contains its own flexure hinge, segmenting the stress distribution across multiple components rather than concentrating it on a single hinge. This segmentation allows the system to maintain parallelism while distributing mechanical loads to prevent any single flexure hinge from experiencing excessive stress.
2Device complexity
If a single flexure hinge mechanism is used for leveling, then the structure is simple, but the load is not uniformly distributed causing stress concentration and potential damage
Solution Approach 1:
The mechanism is segmented into four distinct link assemblies positioned at different locations around the reference plane. Each assembly independently supports a portion of the load, creating uniform stress distribution. The segmented structure maintains relative simplicity while achieving load balancing through spatial distribution of identical modular units.
Solution Approach 2:
The four link assemblies are positioned symmetrically around the reference plane, creating an equipotential configuration where each hinge experiences equivalent mechanical conditions. This symmetrical arrangement ensures that under uniform loading, each flexure hinge bears an equal share of the load, preventing stress concentration and achieving uniform stress distribution across all hinges.
3Productivity
If the stamp and wafer are contacted without precise parallelism control, then the process is simpler, but the yield of the imprinting is directly affected
Solution Approach 1:
The leveling unit operates as a self-service mechanism that automatically adjusts the stamp's inclination to achieve parallelism with the wafer. The passive link assemblies respond to contact forces and automatically level the stamp without requiring external actuators or active control systems. This self-leveling capability ensures precise parallelism control while maintaining process simplicity, directly improving imprinting yield through consistent contact 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
The solution ensures uniform contact and pressure application between the wafer and the stamp, enhancing the yield of the imprint process while preventing mechanism damage from excessive stress, and allows for flexible design and efficient operation in high-load thermal imprint processes.
Implementation Method 1
The plurality of link parts connects the base plate with the moving plate, is spaced apart from each other by a predetermined distance along a circumferential direction with respect to a center of the reference plane, and is elastically and independently transformed by a pressing force applied to the reference plane to adjust an inclination of the moving plate.
Data Source
AI summary
In a leveling unit for imprinting and an imprint apparatus having the leveling unit, the leveling unit includes a base plate, a moving plate and a plurality of link parts. The moving plate is spaced apart from the base plate, and has a reference plane heading for an opposite direction of the base plate. The plurality of link parts connects the base plate with the moving plate, is spaced apart from each other by a predetermined distance along a circumferential direction with respect to a center of the reference plane, and is elastically and independently transformed by a pressing force applied to the reference plane to adjust an inclination of the moving plate.