Interferometric Lithography Grating-Mask Wafer Nanopatterning

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Solution Overview

Problem

Current methods for large-area nanopatterning, such as conventional lithography and nanoimprint lithography, face challenges in achieving high-throughput, cost-effective, and uniform exposure across full wafer scales due to limitations in longitudinal and transverse coherence, intensity uniformity, and pattern distortion, particularly in three-dimensional patterns.

Innovation Solution

The method employs a laser light source with beam conditioning and translation optics to expand the beam and utilize a grating beam splitter with anti-reflection coating and phase/amplitude gratings, along with recombination optics in a retro-reflector configuration to ensure uniform exposure across a full wafer, using beam wobblers to maintain intensity pattern stability and block 0-order diffraction, allowing for high-speed and low-cost nanopatterning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional lithography is used, then high resolution is achieved, but large-area patterning capability is limited

Engineering Contradiction:

ImproveresolutionVSAvoidpatterning area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent segments the illumination area into multiple independent illumination zones that can be simultaneously exposed. By using a large-area mask divided into multiple zones and illuminating them in parallel, the system achieves both high resolution (through photolithography processes) and large-area patterning capability, resolving the contradiction between resolution and patterning area.

Inventive Principle:

Principle #1Segmentation

2Area of stationary object

If nanoimprint lithography is used, then large-area patterning is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvepatterning areaVSAvoidmanufacturing cost

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent uses photolithography to create patterns by copying designs from masks onto wafers through optical projection. This approach avoids the need for expensive physical contact masks required in nanoimprint lithography. The optical copying process enables large-area patterning at lower manufacturing costs by using standard photolithography equipment and materials.

Inventive Principle:

Principle #26Copying

3Area of stationary object

If interferometric lithography is used, then large-area patterning is achieved, but exposure time increases

Engineering Contradiction:

Improvepatterning areaVSAvoidexposure time

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The patent implements continuous wave (CW) laser illumination to provide sustained exposure across the entire large-area mask simultaneously. This continuous illumination approach eliminates the need for sequential scanning or step-and-repeat methods, maintaining constant exposure action across the full patterning area and significantly reducing total exposure time compared to pulsed or intermittent illumination methods.

Inventive Principle:

Principle #20Continuity of useful action

4Area of stationary object

If laser beam is expanded to cover full wafer, then large-area exposure is achieved, but intensity uniformity deteriorates

Engineering Contradiction:

Improveexposure areaVSAvoidintensity uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies local quality optimization by using beam conditioning optics including diffusers and homogenizers that specifically address intensity distribution across different regions of the expanded beam. These optical elements create uniform illumination zones across the large-area mask, ensuring consistent exposure intensity throughout the full exposure area while maintaining the expanded beam coverage.

Inventive Principle:

Principle #3Local 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 approach enables robust, high-speed, and low-cost full-wafer nanopatterning with improved uniformity and coherence, suitable for high-volume manufacturing, overcoming previous limitations in intensity uniformity and pattern distortion, and enabling efficient large-area patterning.

Implementation Method 1

interferometric lithography

Methodology Applied

Scientific EffectInterference: Interference

Implementation Method 2

grating beam splitter with anti-reflection coating and phase/amplitude gratings

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 3

exposing the full wafer photoresist-coated target

Methodology Applied

Scientific EffectPhotochemical reaction: Photopolymerisation

Data Source

PatentUS12092959B1Interferometric lithography grating-mask-based wafer-scale large-area nanopatterning

Publication Date: 2024.09.17 UNM RAINFOREST INNOVATIONS

AI summary

According to examples of the present disclosure, a method for large-area, full-wafer nanopatterning is disclosed. The method includes providing a laser light source; providing beam conditioning and translation optics to expand the beam to illuminate a full wafer area; providing a grating beam-splitter; providing recombination optics to direct at least two beams from the grating beam splitter to a full wafer photoresist-coated target; and exposing the full wafer photoresist-coated target.