Grating Manufacturing via Deformable Layer Stress

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Solution Overview

Problem

Current methods for producing gratings with slanted flanks, such as those used in displays and optronics, face challenges including high production costs, long processing times, and the inability to achieve continuous, step-free slanted profiles, especially on large surfaces.

Innovation Solution

A method involving a deformable structure where initial reliefs are laid upon each other under stress to form slanted walls, allowing for controlled collapsing and precise inclination, eliminating the need for grayscale lithography and reducing the number of steps required, thereby increasing productivity and compatibility with large surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If electron beam lithography with dose modulation is used to produce gratings with slanted flanks, then structures with inclined walls can be obtained, but production time and cost increase significantly

Engineering Contradiction:

Improveslanted flank profileVSAvoidproduction time

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The patent divides the structure into two separate components: a master grating with vertical reliefs and a deformable layer. The master grating is fabricated using standard lithography without dose modulation, and the slanted profile is subsequently formed by mechanically deforming the deformable layer, thus avoiding complex EBL processes while achieving the desired slanted flank geometry

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The master grating with vertical reliefs is fabricated in advance using conventional lithography methods. This preliminary structure serves as a template that guides the subsequent formation of slanted flanks through deformation of the deformable layer, eliminating the need for complex real-time dose modulation during lithography

Inventive Principle:

Principle #10Preliminary action

2Shape

If the number of steps in a staircase structure is increased to approximate a slanted flank, then the profile becomes smoother, but production time and cost increase

Engineering Contradiction:

Improvesmooth slanted profileVSAvoidproduction cost

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The patent replaces the complex multi-step lithographic process with a mechanical deformation approach. Instead of creating multiple lithography steps to approximate a slanted profile, a single lithography step creates vertical reliefs, and subsequent mechanical deformation of the deformable layer produces the smooth slanted profile, significantly reducing production complexity and cost

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Shape

If thermal annealing is applied to smooth the staircase profile, then continuous slanted flanks can be obtained, but the method is not compatible with large surfaces and high production rates

Engineering Contradiction:

Improvecontinuous slanted flankVSAvoidsurface area

Core Design Contradiction:

ShapeVSArea of stationary object

Solution Approach 1:

The patent extracts the smoothing function from the lithography process itself and separates it into a subsequent mechanical deformation step applied to the deformable layer. This allows the master grating to be fabricated using standard high-throughput lithography on large surfaces, while the slanted profile formation occurs separately through controlled deformation, maintaining compatibility with industrial production scales

Inventive Principle:

Principle #2Taking out (Extraction)

4Shape

If thermal annealing is used to creep the resin, then slanted profiles can be formed, but discontinuities and hooks remain in the flank

Engineering Contradiction:

Improveslanted flank profileVSAvoidflank continuity

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The patent uses the master grating with vertical reliefs as a precise template or copy master. The deformable layer is deformed to conform to this master structure, ensuring that the resulting slanted flanks accurately replicate the desired geometry without the discontinuities and hooks that arise from thermal annealing methods

Inventive Principle:

Principle #26Copying

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 method enables the efficient production of gratings with smooth, slanted walls and precise angle control, reducing production time and costs while avoiding the formation of hooks or steps, and is compatible with large-scale industrial applications.

Implementation Method 1

laying the reliefs of the initial grating on one another, by application of at least one stress on the structure, in such a way that walls facing two adjacent reliefs come into contact

Methodology Applied

Scientific EffectStress-induced deformation: Deformation

Data Source

PatentUS11456403B2Method of manufacturing a microelectronic device having an array of inclined reliefs

Publication Date: 2022.09.27 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

A method is provided for producing a microelectronic device having a subsequent grating of reliefs of which at least one wall is slanted, the method including providing a structure including a base, and an initial grating of reliefs, each relief having at least one proximal end in contact with the base, a distal end, and at least one wall extending between the proximal end and the distal end; and laying the reliefs of the initial grating on one another, by application of at least one stress on the structure, such that walls facing two adjacent reliefs come into contact, thus generating at least one subsequent grating of reliefs of which at least one wall is slanted.