Non-Chemically Amplified Resist Patterning for EUV Resolution

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Solution Overview

Problem

Current resist compositions for EUV lithography face challenges in achieving high sensitivity and resolution due to acid diffusion, pattern swelling, and shot noise, leading to issues like pattern collapse and disconnection, especially for feature sizes below 16 nm.

Innovation Solution

A resist pattern forming process using a non-chemically amplified resist composition containing a hypervalent iodine compound and a carboxy group-containing compound, developed by dry etching, which enhances sensitivity and resolution for high-energy radiation processes like EB and EUV lithography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemically amplified resist composition is used to enhance sensitivity and contrast, then sensitivity and contrast are improved, but acid diffusion causes image blur and resolution deteriorates

Engineering Contradiction:

Improvesensitivity and contrastVSAvoidresolution

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent removes the chemically amplified mechanism (acid generator and photoacid) from the resist composition, extracting the source of acid diffusion that causes image blur. This enables the use of non-chemically amplified resist materials that achieve high resolution without the harmful side effects of acid diffusion, while maintaining adequate sensitivity through alternative mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental mechanism of resist activation from chemical amplification to direct photochemical or physical effects. By altering the resist composition parameters to exclude acid generators and use alternative photo-sensitive materials, the system achieves both high resolution and acceptable sensitivity through different physical-chemical parameters.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If wet process development is used to develop resist pattern, then development is simple, but pattern swelling and surface tension influence resolution

Engineering Contradiction:

Improvedevelopment simplicityVSAvoidresolution

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the wet chemical development process with a dry etching process. This substitution eliminates the mechanical and chemical issues of wet development (swelling, surface tension) while maintaining development effectiveness. The dry etching process provides superior resolution by avoiding the physical limitations of liquid-based development.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Length of moving object

If EUV lithography is used to achieve smaller feature size, then feature size is reduced, but shot noise increases and sensitivity decreases

Engineering Contradiction:

Improvefeature sizeVSAvoidsensitivity

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent changes the resist material parameters to use non-chemically amplified materials with higher photochemical efficiency and lower stochastic variability. By selecting resist compositions that respond more deterministically to EUV photons, the system compensates for shot noise and maintains sensitivity despite the reduced photon count inherent in EUV lithography.

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

The process achieves high sensitivity and resolution, reducing the impact of acid diffusion and shot noise, resulting in precise micropatterning with improved pattern shape and stability.

Implementation Method 1

resist composition containing: a hypervalent iodine compound... exposing the resist film to high-energy radiation

Methodology Applied

Scientific EffectAbsorption of high-energy radiation: Absorption (EM radiation)

Implementation Method 2

non-chemically amplified resist composition... developing the heated resist film by dry etching to form a resist pattern

Methodology Applied

Scientific EffectPhotochemical reaction: Photodissociation

Implementation Method 3

developing the heated resist film by dry etching

Methodology Applied

Scientific EffectPlasma etching: Plasma

Data Source

PatentUS20250377593A1Resist pattern forming process

Publication Date: 2025.12.11 SHIN ETSU CHEMICAL CO LTD

AI summary

A resist pattern forming process is provided that includes a step in which a non-chemically amplified resist composition excellent in sensitivity and maximum resolution is used and the exposed resist film is developed by dry etching to form a positive or negative resist pattern when processed by photolithography using high-energy radiation. A resist pattern forming process comprising the steps of: (i) applying a resist composition containing: a hypervalent iodine compound having the formula (1), (2), or (3); a carboxy group-containing compound; and a solvent onto a substrate or onto an underlayer film laminated on a substrate to form a resist film, (ii) exposing the resist film to high-energy radiation, (iii) heating the exposed resist film, and (iv) developing the heated resist film by dry etching to form a resist pattern.