Electronic Lithography via Electrostatic Screening

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Solution Overview

Problem

Low-energy electron lithography faces limitations in spatial resolution due to significant electron scattering, while high-energy electron lithography causes thermal deformation and accuracy issues.

Innovation Solution

Electron implantation in a substrate or dielectric layer generates a repulsive electric field to confine and reduce electron diffusion during the lithography process, using a pre-implantation pattern that surrounds the lithography pattern to minimize scattering and thermal effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high-energy electron beams (50-100 keV) are used, then spatial resolution is improved, but thermal deformation of the substrate occurs

Engineering Contradiction:
Improvespatial resolutionVSAvoidsubstrate thermal deformation
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The patent changes the energy parameter of electron beams from high (50-100 keV) to low (5-10 keV) range, fundamentally altering the interaction mechanism with the substrate to avoid thermal effects while maintaining sufficient penetration depth through optimized beam energy selection

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a dielectric layer as an intermediary between the electron beam and the substrate. This layer absorbs the electron beam energy, preventing direct thermal interaction with the substrate while still allowing effective pattern transfer to the resist material

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If low-energy electron beams (5-10 keV) are used, then thermal deformation is reduced, but electron scattering increases limiting spatial resolution

Engineering Contradiction:
Improvesubstrate thermal deformationVSAvoidspatial resolution
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The dielectric layer serves as a mediator that modifies the scattering behavior of low-energy electrons. It provides a controlled interface that reduces random scattering while maintaining the low energy advantage of minimal thermal deformation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the dielectric layer thickness and material properties to control electron scattering characteristics, transforming the harmful scattering effect into a controllable parameter that can be tuned for optimal resolution

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If an intermediate low atomic density layer is inserted, then electron scattering is reduced, but device complexity increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The dielectric layer performs multiple functions simultaneously: it acts as an electron scattering moderator, provides pattern transfer interface, and serves as part of the final device structure, thereby reducing overall process complexity despite adding a layer

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances spatial resolution by reducing electron scattering and thermal deformation, allowing for precise pattern transfer without compromising accuracy.

Implementation Method 1

These electrons are spatially distributed so as to generate a repulsive electric field which opposes the diffusion of the electrons used for the actual lithography step

Methodology Applied
Scientific EffectElectrostatic repulsion: Electrostatics

Implementation Method 2

exposing the resin to an electron beam so as to cause localized physical and chemical changes within it

Methodology Applied
Scientific EffectElectron beam exposure: Electron Impact Desorption

Implementation Method 3

A geometric pattern is therefore transferred to the resin by the electron beam

Methodology Applied
Scientific EffectElectron beam deposition: Electron Beam

Data Source

PatentEP3420412B1Method for electronic lithography with electrostatic screening
Publication Date: 2019.10.09 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3420412B1 patent drawingFigure 1A~1C
  • EP3420412B1 patent drawingFigure 1D~2
  • EP3420412B1 patent drawingFigure 3

AI summary

The invention relates to a method for electronic lithography comprising the following steps: implanting electrons, following a first pattern, in a substrate (S), or in a dielectric layer (CD) deposited on the surface of said substrate; depositing a resin (R) for electronic lithography on the surface of said substrate or of said sacrificial dielectric layer; and exposing said resin by means of a beam of electrons (FL) following a second pattern, then developing same; said first and second patterns consisting of unit cells, the unit cells of said first pattern (MPI) at least partially surrounding the unit cells of said second pattern (ML).