3D Laser Lithography Edge Dose Control for Precise Surface Gradients

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Solution Overview

Problem

Laser lithography methods face challenges in achieving high precision and design freedom due to resolution limits and inaccuracies in reproducing continuous surface gradients and densely packed structures, leading to undesirable deviations between the desired and resulting structures.

Innovation Solution

A method using direct laser writing in a volume of lithography material, where the exposure dose is varied spatially and locally through multi-photon absorption, allowing for precise control of the structure by changing the exposure dose in edge sections of partial structures to compensate for inaccuracies and create desired surface features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the overall structure is broken down into smaller substructures to improve precision, then manufacturing precision is improved, but the number of substructures increases leading to longer process time

Engineering Contradiction:
ImproveprecisionVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the exposure dose based on the local geometric characteristics (slope and curvature) of the outer surface. This allows the system to maintain high precision for complex surface gradients without requiring excessive subdivision into substructures, thereby reducing the total number of writing operations and process time.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the overall structure is broken down into smaller substructures to improve precision, then manufacturing precision is improved, but device complexity increases due to more substructures to generate

Engineering Contradiction:
ImproveprecisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses parameter changes by modifying the exposure dose according to local surface geometry (slope and curvature). This approach maintains manufacturing precision for complex structures without requiring complex device configurations or excessive substructure generation, thereby reducing computational and operational complexity.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If exposure dose is increased in edge sections to compensate for step effects, then manufacturing precision is improved, but energy consumption increases

Engineering Contradiction:
Improvesurface gradient accuracyVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by adjusting the exposure dose specifically in edge sections where the laser beam writes structure details, based on the local slope and curvature of the outer surface. This localized adjustment improves surface gradient accuracy without uniformly increasing energy consumption across the entire structure, thereby optimizing energy efficiency.

Inventive Principle:
Principle #3Local quality

4Manufacturing precision

If finer screening of the overall structure is performed only in areas with strong contour changes, then manufacturing precision is improved, but computing effort increases leading to longer process time

Engineering Contradiction:
Improveprecision in contour areasVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies local quality by performing finer screening and adjusting the exposure dose only in areas with strong contour changes (edge sections with high slope and curvature). This localized approach improves precision where needed without unnecessarily increasing computing effort and process time for areas with simple geometry.

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 the creation of precise, continuous surface structures with reduced inaccuracies and process times, allowing for the generation of complex shapes with improved surface gradients and reduced 'step' and 'bulging' effects.

Implementation Method 1

an exposure dose is radiated into the lithography material in a spatially resolved manner in a focus area of a laser writing beam using two-photon absorption or multi-photon absorption in general

Methodology Applied
Scientific EffectTwo-photon absorption:

Implementation Method 2

an exposure dose is radiated into the lithography material in a spatially resolved manner in a focus area of a laser writing beam using two-photon absorption or multi-photon absorption in general

Methodology Applied
Scientific EffectMulti-photon absorption:

Data Source

PatentEP3621766B1Method of producing a 3D structure by means of laser lithography with a modified exposure dose at edge portions, and corresponding computer program product
Publication Date: 2022.01.05 NANOSCRIBE HLDG GMBH
  • EP3621766B1 patent drawingFigure 1~2
  • EP3621766B1 patent drawingFigure 3~4
  • EP3621766B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for producing a three-dimensional overall structure (10) by means of laser lithography, the overall structure (10) being approximated by at least one partial structure (14), wherein, for the purposes of writing the partial structure (14), an exposure dose is radiated into the lithography material in a focal region of a laser writing beam while exploiting multi-photon absorption. Here, in the partial structure (14), the exposure dose in those edge portions (20) that immediately adjoin an external surface (12) of the overall structure (10) to be produced is modified in comparison with the remaining partial structure (14). The invention also relates to a computer program product adapted to the method.