Imprint Lithography Optical Encoder Alignment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current imprint lithography systems face challenges in achieving high accuracy alignment of successive layers, particularly in manufacturing multiple layer structures, due to difficulties in aligning patterns correctly, which can lead to improper device component contact and functionality issues.

Innovation Solution

An optical encoder system with a radiation output, first and second diffraction gratings, and a detector is used to provide an alignment signal by illuminating the second diffraction grating and detecting diffracted radiation, allowing for precise alignment of the imprint template with the substrate, enabling accurate overlay of multiple layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If imprint lithography is used to manufacture multiple layer structures, then manufacturing precision can be improved, but alignment accuracy between successive layers deteriorates

Engineering Contradiction:

Improveoverlay precisionVSAvoidalignment accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by incorporating alignment marks and diffraction gratings into the template and substrate before the imprinting process. These alignment features are prepared in advance to enable precise alignment measurement during the manufacturing of multiple layer structures, resolving the contradiction between manufacturing precision and alignment accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical alignment methods with an optical measurement system. An optical encoder uses diffraction gratings and radiation to measure alignment positions, substituting mechanical alignment procedures with optical field-based measurement, thereby improving alignment accuracy without compromising manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional optical lithography is used, then alignment can be achieved, but manufacturing precision deteriorates due to diffraction limitations

Engineering Contradiction:

Improvealignment capabilityVSAvoidfeature resolution

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent substitutes optical lithography with imprint lithography, replacing the optical field-based patterning process with a mechanical imprinting process. This substitution eliminates diffraction limitations that constrain optical lithography, enabling superior manufacturing precision while maintaining alignment capabilities through the optical encoder system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters by transitioning from optical wavelength-based patterning to direct mechanical imprinting. This parameter change removes the diffraction limit constraint, allowing feature sizes smaller than what conventional optical lithography can achieve, thereby improving manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

3Length of moving object

If optical lithography with shorter wavelength is used, then feature size can be reduced, but device complexity and cost increase

Engineering Contradiction:

Improvefeature sizeVSAvoidoptics complexity

Core Design Contradiction:

Length of moving objectVSDevice complexity

Solution Approach 1:

The patent replaces complex optical systems with a simpler mechanical imprinting process. Instead of using shorter wavelength optical sources and complex optics to reduce feature size, the invention uses direct mechanical contact between a template and substrate, eliminating the need for advanced optical components while achieving smaller feature sizes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs disposable or replaceable templates that can be easily fabricated and exchanged, rather than investing in expensive, complex optical systems. This approach reduces device complexity and cost while maintaining the capability to produce small features, as the template can be directly imprinted onto the substrate.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 solution enhances alignment accuracy to about 100 nm, facilitating the fabrication of multiple layer structures with improved overlay precision and reducing pattern distortions, thereby ensuring proper device component contact and functionality.

Implementation Method 1

an optical encoder having a radiation output, a first diffraction grating, and a detector, the radiation output arranged to illuminate a second diffraction grating and the detector positioned to detect radiation diffracted by the first and second diffraction gratings

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS7618250B2Imprint lithography

Publication Date: 2009.11.17 ASML NETHERLANDS BV

AI summary

An imprint lithography apparatus is disclosed that has a template holder configured to hold an imprint template, a substrate table, and an optical encoder, the optical encoder having a radiation output, a first diffraction grating, and a detector, the radiation output arranged to illuminate a second diffraction grating and the detector positioned to detect radiation diffracted by the first and second diffraction gratings to provide an alignment signal.