Metal-Containing EUV Resist Materials for Sub-11nm Patterning

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Solution Overview

Problem

Current EUV lithography technologies face challenges in developing radiation-sensitive resist materials that can achieve high resolution patterns at wavelengths below 11 nm, particularly due to issues with resist film thickness, blurring, and pattern collapse, which are not adequately addressed by materials optimized for 13.5 nm wavelengths.

Innovation Solution

The use of compounds containing specific metals such as Ta, W, Re, Os, Ir, Ni, Cu, or Zn in resist materials for EUV lithography, which provide thin films with high absorption and reduced blurring, minimizing pattern collapse and enhancing the resist's strength and etch resistance by controlling the mean free path of photo-generated electrons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If resist materials optimized for 13.5 nm wavelengths are used, then the process is well-established and reliable, but the resolution and depth of focus are insufficient for features below the 11 nm node

Engineering Contradiction:
ImproveresolutionVSAvoidprocess reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the wavelength parameter from 13.5 nm to below 11 nm (specifically 6.5-6.9 nm), which fundamentally alters the resolution capability and depth of focus of the lithographic system, enabling sub-11 nm feature printing while maintaining process reliability through optimized resist formulations

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the resist film thickness is reduced to achieve high resolution patterns, then the blurring is reduced, but the resist film becomes too weak and collapses during processing

Engineering Contradiction:
Improvepattern resolutionVSAvoidresist film strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent employs composite resist materials containing metal compounds (Ta, W, Re, Os, Ir, Ni, Cu, or Zn) combined with organic resin components. This composite structure provides both the thin film capability for reduced blurring and the enhanced mechanical strength to prevent pattern collapse during processing

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The metal compounds are distributed within the resist matrix to provide localized regions of high electron density and strength, allowing the resist to maintain structural integrity in critical pattern regions while keeping overall film thickness minimal for high resolution

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the resist film thickness is reduced to improve resolution, then the blurring is reduced, but the etch resistance of the resist decreases

Engineering Contradiction:
Improvepattern resolutionVSAvoidetch resistance
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The metal-containing compounds in the composite resist structure provide enhanced etch resistance through their high atomic number and density, compensating for the reduced film thickness while maintaining the resolution benefits of thin films

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the compositional parameters of the resist by incorporating metal compounds with specific atomic properties, which fundamentally alters the etch resistance characteristics independent of film thickness, allowing thin films to achieve both high resolution and adequate etch protection

Inventive Principle:
Principle #35Parameter changes

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

These metal-containing resist materials achieve high resolution and reduced blurring, enabling the production of features with aspect ratios below 3, and are suitable for wavelengths as low as 6.x nm, improving the overall performance and reliability of EUV lithography processes.

Implementation Method 1

The use of compounds comprising at least one of the following elements: Ta, W, Re, Os, Ir, Ni, Cu or Zn in a resist material for an EUV lithographic process wherein the wavelength of the EUV radiation used in said process is less than 11 nm

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

controlling the mean free path of photo-generated electrons

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2729844B1Lithographic patterning process and resists to use therein
Publication Date: 2021.07.28 ASML NETHERLANDS BV
  • EP2729844B1 patent drawingFigure 1~2
  • EP2729844B1 patent drawingFigure 3
  • EP2729844B1 patent drawing

AI summary

A lithographic process includes the use of a silicon-containing polymer or a compound that includes at least one element selected from the group consisting of: Ta, W, Re, Os, Ir, Ni, Cu or Zn in a resist material for an EUV lithographic process. The wavelength of the EUV light used in the process is less than 11 nm, for example 6.5-6.9 nm. The invention further relates to novel silicon-containing polymers.