EUV Resist Composition with Ortho-Halogen Phenolic Hydroxyl Groups

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Solution Overview

Problem

EUV lithography faces challenges in achieving high sensitivity and reducing line width roughness (LWR) and critical dimension uniformity (CDU) due to variations in photon number, despite attempts to increase photon absorption with iodine-substituted resins, which only result in limited acid generation efficiency.

Innovation Solution

A resist composition featuring a polymer with phenolic hydroxyl groups at the ortho-position to the aromatic ring and halogen atoms, particularly iodine, which enhances sensitivity and acid generation efficiency by generating secondary electrons during EUV exposure, improving CDU and process margin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If iodine-substituted resins are used to increase photon absorption, then sensitivity is improved, but acid generation efficiency remains limited

Engineering Contradiction:

Improvephoton absorptionVSAvoidacid generation efficiency

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a phenolic hydroxyl group as an intermediary substance that mediates between absorbed photons and acid generation. The phenolic hydroxyl group acts as a mediator that converts photon energy into effective acid generation, resolving the contradiction between photon absorption and acid generation efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite molecular structure combining iodine atoms (for photon absorption) with phenolic hydroxyl groups (for acid generation). This composite approach integrates the advantages of both components: iodine provides high photon absorption while phenolic hydroxyl provides efficient acid generation

Inventive Principle:

Principle #40Composite materials

2Productivity

If more photons are absorbed to reduce variation, then sensitivity increases, but line width roughness and critical dimension uniformity deteriorate

Engineering Contradiction:

ImprovesensitivityVSAvoidline width roughness and critical dimension uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the resist by introducing phenolic hydroxyl groups with specific ortho-substitution patterns. This parameter change modifies how the resist responds to photons, achieving both high sensitivity and low LWR through optimized molecular structure

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 resist composition exhibits high sensitivity and improved CDU, enabling efficient pattern formation with reduced LWR and enhanced process adaptability, particularly under EUV exposure.

Implementation Method 1

Among the halogen atoms, iodine is highly absorptive to EUV radiation of wavelength 13.5 nm

Methodology Applied

Scientific EffectEUV absorption: Absorption (EM radiation)

Implementation Method 2

the phenolic hydroxyl group being optionally protected with an acid labile group, and having a halogen atom on the aromatic ring. When exposed to high-energy radiation, especially EUV, the resist composition exhibits a high sensitivity

Methodology Applied

Scientific EffectSecondary electron generation: Photoelectric Effect

Data Source

PatentUS10915021B2Monomer, polymer, resist composition, and patterning process

Publication Date: 2021.02.09 SHIN ETSU CHEMICAL CO LTD

AI summary

A monomer having formula (A) is provided. RA is H, methyl or trifluoromethyl, X1 is a single bond, ether, ester or amide bond, Ra is a C1-C20 monovalent hydrocarbon group, Rb is H or an acid labile group, X is halogen, n is an integer of 1 to 4, m is an integer of 0 to 3, and 1≤n+m≤4. A resist composition comprising a polymer derived from the monomer has a high sensitivity to high-energy radiation, especially EUV.