Negative Resist Composition for Lithography

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current negative resist compositions for electron beam or X-ray lithography fail to simultaneously achieve high sensitivity, high resolution, good pattern profile, and reduced line edge roughness, especially in the ultrafine region, leading to impaired dimensional precision and pattern collapse.

Innovation Solution

A negative resist composition comprising an alkali-soluble polymer with a specific structure, a crosslinking agent, an acid generator, a quaternary ammonium salt, and an organic carboxylic acid, which forms a resist film that maintains sensitivity and resolution while improving line edge roughness and pattern profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher sensitivity is pursued in negative resist for electron beam lithography, then sensitivity is improved, but line edge roughness worsens and resolution deteriorates

Engineering Contradiction:

ImprovesensitivityVSAvoidline edge roughness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses a composite resist system comprising a novolak resin as the base polymer, a cyclic carbon dioxide-generating compound as acid generator, and a specific additive combination (triethylamine and/or tetramethylammonium hydroxide with carboxylic acid). This composite formulation achieves high sensitivity while maintaining smooth line edges and good resolution by balancing the chemical reactions during exposure and development.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the resist, specifically incorporating amino compounds (triethylamine, tetramethylammonium hydroxide) in controlled amounts (0.1-10 wt% based on polymer) along with carboxylic acids. This parameter adjustment optimizes the resist's response to electron beam exposure, achieving high sensitivity without compromising line edge quality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If higher sensitivity is pursued in negative resist, then sensitivity is improved, but resolution deteriorates

Engineering Contradiction:

ImprovesensitivityVSAvoidresolution

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The resist composition combines novolak resin with specific additives (amino compounds and carboxylic acids) to create a composite system that maintains high resolution while achieving improved sensitivity. The synergistic interaction between components allows efficient signal amplification during exposure without compromising the sharpness of the developed pattern.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

By adjusting the chemical composition parameters, particularly the addition of amino compounds and carboxylic acids in specific ratios, the patent optimizes the resist's sensitivity-resolution trade-off. The amino compounds enhance sensitivity through catalytic effects while the overall formulation maintains the resolution necessary for ultrafine patterning.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If higher sensitivity is pursued in negative resist, then sensitivity is improved, but pattern profile deteriorates

Engineering Contradiction:

ImprovesensitivityVSAvoidpattern profile

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The patent employs a composite resist formulation including novolak resin, cyclic carbon dioxide-generating acid generator, amino compounds, and carboxylic acids. This composite system maintains excellent pattern profile with vertical sidewalls and minimal erosion while achieving high sensitivity, by controlling the crosslinking and dissolution behavior during processing.

Inventive Principle:

Principle #40Composite materials

4Reliability

If higher sensitivity is pursued in negative resist, then sensitivity is improved, but dimensional precision deteriorates due to line edge roughness

Engineering Contradiction:

ImprovesensitivityVSAvoiddimensional precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The resist composition uses a carefully designed composite system with novolak resin, acid generator, amino compounds, and carboxylic acids that produces smooth line edges during development. This eliminates the transfer of roughness to the underlying shielding layer during etching, thereby maintaining high dimensional precision while achieving improved sensitivity.

Inventive Principle:

Principle #40Composite materials

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 composition achieves high sensitivity, high resolution, good pattern profile, and reduced line edge roughness, enhancing the precision of semiconductor device processing and photomask fabrication, particularly in the ultrafine region.

Implementation Method 1

a compound capable of generating an acid upon irradiation with actinic rays or radiation

Methodology Applied

Scientific EffectPhotochemical reaction: Photopolymerisation

Data Source

PatentUS9034560B2Negative resist composition and pattern forming method using the same

Publication Date: 2015.05.19 FUJIFILM CORP

AI summary

A negative resist composition, includes: (A) an alkali-soluble polymer containing a specific repeating unit as defined in the specification; (B) a crosslinking agent capable of crosslinking with the alkali soluble polymer (A) under an action of an acid; (C) a compound capable of generating an acid upon irradiation with actinic rays or radiation; (D) a specific quaternary ammonium salt as defined in the specification; and (E) an organic carboxylic acid, and a pattern forming method uses the composition.