Metal Oxide Light Diffusing Layer for Laser Reflection Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Laser interference lithography on reflective substrates faces issues with undesired exposure and cross-linking due to laser beam reflection, which degrades the pattern in the photoresist layer, and existing solutions like transparent substrates and anti-reflective coatings are not conducive for electroplating applications.

Innovation Solution

A light diffusing layer with an outer metal oxide layer, such as copper oxide, is sandwiched between the substrate and the photoresist layer, featuring a rough surface to diffuse laser light and reduce reflection, while also being convertible to a conductive metallic layer during electroplating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If transparent substrates are used to reduce undesired exposure, then reflection of laser beams is reduced, but electrical conductivity for electroplating is lost

Engineering Contradiction:

Improveundesired exposureVSAvoidelectroplating capability

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The substrate system is segmented into multiple functional layers: a transparent substrate base layer and a separate light diffusing layer with metal oxide particles. This segmentation allows each layer to perform its specific function - the substrate provides structural support and transparency, while the light diffusing layer reduces reflection and maintains electroplating capability through conductive metal oxide particles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The light diffusing layer is formed as a composite material containing transparent binder resin and metal oxide particles (such as titanium oxide, zinc oxide, or indium oxide). This composite structure provides both the light diffusing property needed to reduce reflection and the electrical conductivity required for electroplating, resolving the contradiction between optical and electrical requirements.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If anti-reflective coatings are applied to reduce laser beam reflection, then undesired cross-linking is reduced, but electrical conductivity is lost

Engineering Contradiction:

Improveundesired cross-linkingVSAvoidelectroplating capability

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The optical properties are modified by changing the particle size distribution of the metal oxide particles in the light diffusing layer. By controlling parameters such as average particle diameter (0.1-10 μm) and incorporating a distribution of particle sizes, the layer effectively diffuses laser light to reduce reflection-induced cross-linking while maintaining electrical conductivity through the same particle network.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If light diffusing elements are added to reduce reflection, then laser beam reflection is minimized, but manufacturing complexity increases

Engineering Contradiction:

Improvelaser beam reflectionVSAvoidlayer structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple functions are merged into a single light diffusing layer: light diffusion to reduce reflection, electrical conductivity for electroplating, and adhesion between the substrate and photoresist. By combining these functions in one integrated layer rather than using separate layers for each function, the overall device complexity is reduced while achieving all necessary performance requirements.

Inventive Principle:

Principle #5Merging (Combining)

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 configuration minimizes undesired exposure and maintains a well-defined 3D void space pattern in the photoresist layer, enabling effective electroplating and addressing the conductivity requirements for applications.

Implementation Method 1

The light diffusing layer includes an outer metal oxide layer with an outer rough surface configured to diffuse light from a laser during laser interference lithography of the photoresist layer

Methodology Applied

Scientific EffectLight diffusion: Scattering

Implementation Method 2

The outer metal oxide layer is also configured to be reduced to a conductive metallic layer during electroplating of the substrate

Methodology Applied

Scientific EffectReduction: Reduction

Data Source

PatentUS11815822B2Electrodeposition compatible anti-reflection coatings for laser interference lithography applications

Publication Date: 2023.11.14 TOYOTA JIDOSHA KK

AI summary

A component with a reflective substrate, a photoresist layer disposed on the reflective substrate, and a light diffusing layer sandwiched between the reflective substrate and the photoresist layer is provided. The light diffusing layer includes an outer metal oxide layer with an outer rough surface configured to diffuse laser light during laser interference lithography of the photoresist layer. The outer metal oxide is also configured to be reduced to a conductive metallic layer during electroplating of the substrate. The outer metal oxide layer includes a plurality of elongated light diffusing elements extending in an outward direction from the substrate such that the outer rough surface diffuses at least 90% of laser light during the laser interference lithography of the photoresist layer.