Positive Resist Composition for High-Resolution EUV Patterning

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Solution Overview

Problem

Existing chemically amplified resist compositions face challenges in achieving high resolution, small line edge roughness (LER), pattern profile stability, and etching resistance, particularly in photolithography processes using high-energy radiation, due to acid diffusion and poor solvent solubility, leading to pattern collapse and dimensional uniformity issues.

Innovation Solution

A chemically amplified positive resist composition utilizing a polymer containing a repeat unit derived from an onium salt with an aromatic sulfonate anion and a triarylsulfonium cation, along with specific repeat units, enhances solvent solubility and lithographic performance, providing improved resolution, LER, and etching resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional acid generators are used to prevent acid diffusion, then resolution is improved, but pattern collapse occurs due to poor solvent solubility

Engineering Contradiction:

ImproveresolutionVSAvoidpattern collapse

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent modifies the molecular structure of the acid generator by introducing specific repeat units with sulfonic acid groups and aromatic hydrocarbon groups in controlled ratios (0.1-10 mol% and 89.9-90 mol% respectively). This parameter change optimizes both the acid diffusion control and solvent solubility, preventing pattern collapse while maintaining high resolution

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite acid generator structure combining multiple functional repeat units: sulfonic acid groups for acid diffusion control, aromatic hydrocarbon groups for solubility enhancement, and electron-withdrawing groups for sensitivity improvement. This composite approach resolves the contradiction between resolution and pattern stability

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If acid diffusion is controlled by bonding sulfonic acid to resin, then LER is reduced, but solubility in organic solvent deteriorates

Engineering Contradiction:

Improveline edge roughnessVSAvoidsolvent solubility

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies local quality by strategically placing sulfonic acid groups at specific positions within the polymer chain (0.1-10 mol%) rather than uniformly distributing them. This localized approach maintains acid diffusion control benefits while minimizing negative impact on overall solubility

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the solubility parameter by introducing aromatic hydrocarbon groups (89.9-90 mol%) that provide hydrophobic character and enhance organic solvent compatibility, counterbalancing the hydrophilic sulfonic acid groups while maintaining acid diffusion control

Inventive Principle:

Principle #35Parameter changes

3Strength

If polyhydroxystyrene is used for KrF lithography, then etching resistance is improved, but absorption at 200 nm wavelength increases

Engineering Contradiction:

Improveetching resistanceVSAvoidlight absorption

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical composition parameters by replacing polyhydroxystyrene with a novel polymer structure containing sulfonic acid groups and aromatic hydrocarbon groups. This parameter change maintains etching resistance through the aromatic structure while reducing UV absorption by eliminating the hydroxyl groups that cause strong absorption at 200 nm

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 composition achieves high-resolution patterns with small LER and excellent etching resistance, suitable for use in microfabrication techniques, particularly in EB lithography and EUV lithography, achieving effective solvent solubility and resistance to pattern collapse and deterioration of dimensional uniformity, and effective solvent solubility, suitable as a chemically amplified positive resist material.

Implementation Method 1

a chemically amplified positive resist composition utilizing a polymer containing a repeat unit derived from an onium salt with an aromatic sulfonate anion and a triarylsulfonium cation

Methodology Applied

Scientific EffectPhotoacid generation: Photodissociation

Implementation Method 2

One outstanding problem is the diffusion of an acid, which has a significant impact on the resolution of a chemically amplified resist film

Methodology Applied

Scientific EffectAcid diffusion: Diffusion

Implementation Method 3

a base polymer (A) containing a polymer adapted to increase its solubility in an alkaline aqueous solution under the action of acid

Methodology Applied

Scientific EffectChemically amplified solubility change: Chemical Bonding

Data Source

PatentEP4675351A1Chemically amplified positive resist composition and resist pattern forming process

Publication Date: 2026.01.07 SHIN ETSU CHEMICAL CO LTD

Figure 1

AI summary

A chemically amplified positive resist composition containing a base polymer (A) which is a polymer whose solubility in an aqueous alkaline solution is increased by the action of an acid, contains a repeat unit containing an aromatic sulfonate anion having the formula (A1-1) and a sulfonium cation having the formula (A1-2) and a repeat unit having the formula (A2), and contains a polymer whose solubility in an aqueous alkaline solution is increased by the action of an acid.