Seamless Large Area Imprint Lithography via Selective Curing

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Solution Overview

Problem

Conventional imprint lithography methods are not suitable for large area substrates as they form seams at the periphery, leading to decreased device efficiency and potential failure in displays like LGPs and LCDs due to pattern irregularities.

Innovation Solution

The method involves separating the curing time of features from the seam and periphery, allowing for the seam and periphery to be cured first or last, and using a filler material to manage seam-like challenges, with options for curing on the master, stamp, or final product, and employing a UV transparent backing plate with multiple masters to create a seamless pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple masters are adhered to one another to pattern large area substrates, then the area of the imprinted substrate is increased, but seams are formed between masters causing pattern irregularities and device failure

Engineering Contradiction:

Improvearea of imprinted substrateVSAvoidpattern regularity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The harmful seam regions between masters are selectively removed or excluded from the imprinting process. The method extracts or isolates these problematic boundary areas so they do not transfer to the stamp or substrate, eliminating the source of pattern irregularities while preserving the beneficial large-area coverage from using multiple masters

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Different regions of the master assembly are treated differently: the central feature regions are imprinted with high precision while the seam regions between masters are treated separately (either removed, filled, or excluded). This local differentiation allows the system to achieve both large area coverage and high pattern regularity by optimizing each region's treatment according to its specific requirements

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If multiple masters are adhered to one another to pattern large area substrates, then the area of the imprinted substrate is increased, but device efficiency decreases due to seams and periphery irregularities

Engineering Contradiction:

Improvearea of imprinted substrateVSAvoiddevice efficiency

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The seam regions, which would normally be harmful sources of defects, are converted into a beneficial control feature. By deliberately managing the seam areas (through removal, filling, or exclusion), the process transforms potential defect sources into defined boundaries that do not compromise device reliability, allowing large-area imprinting to proceed successfully

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If conventional imprint lithography is used on large area substrates, then the process is simple, but seams are imprinted causing light loss and image quality issues

Engineering Contradiction:

Improveprocess simplicityVSAvoidlight loss and image quality

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A mask layer is introduced as an intermediary element between the master and the stamp/substrate. This mask selectively blocks UV light from curing stamp material in seam regions, allowing the imprinting process to proceed simply while preventing harmful seam patterns from being transferred. The mask acts as a mediator that reconciles process simplicity with defect prevention

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enables the creation of large area imprints without seams, improving device efficiency by reducing patterning irregularities and enhancing the functionality of displays by minimizing light loss and image quality issues.

Implementation Method 1

exposing the stamp material to ultraviolet light from the ultraviolet light source to form cured portions and uncured portions of the stamp material

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11774851B2Methods and apparatus for creating a large area imprint without a seam

Publication Date: 2023.10.03 APPLIED MATERIALS INC

AI summary

Embodiments of the present disclosure generally relate to imprint lithography, and more particularly to methods and apparatus for creating a large area imprint without a seam. Methods disclosed herein generally include separating the curing time of the features in a stamp or product from the curing time of the seam and the periphery. The seam and periphery can be cured first or the seam and periphery can be cured last. Additionally, the seam curing operations can be performed on the master, on the stamp, or on the final product.