Halogenated Novolac Resist Underlayer for Etching and Pattern Sensitivity

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Solution Overview

Problem

Existing resist underlayer films face issues with intermixing with resist films, low sensitivity in pattern formation, and inadequate etching rates, particularly when using advanced lithography techniques like EUV light and electron beams.

Innovation Solution

A resist underlayer film-forming composition comprising a novolac resin with phenolic hydroxy groups and directly bonded halogen atoms, along with a solvent, optionally including a crosslinking agent, is used to create a film with high etching rates and sensitivity for pattern formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional resist underlayer film is used, then the substrate is protected, but the etching rate is insufficient and pattern formation sensitivity is low

Engineering Contradiction:

Improvepattern formation sensitivityVSAvoidetching rate

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent modifies the chemical composition parameters of the underlayer film by incorporating specific halogen-containing compounds (bromine or iodine) and controlling the ratio of novolac resin to halogen-containing compound (10:1 to 1:1 by mass). This parameter optimization simultaneously enhances both the etching rate and pattern formation sensitivity without compromising film integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The underlayer composition is designed as a composite material combining novolac resin with halogen-containing compounds. This composite structure provides synergistic effects: novolac resin ensures film adhesion and structural stability, while halogen-containing compounds enhance etching performance and pattern sensitivity, resolving the contradiction between etching rate and sensitivity

Inventive Principle:

Principle #40Composite materials

2Productivity

If the halogen content is increased to improve etching rate, then etching performance improves, but intermixing with resist film occurs

Engineering Contradiction:

Improveetching rateVSAvoidresist film integrity

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent precisely controls the halogen content parameter within optimal ranges (0.1-10 mass% bromine or 0.1-5 mass% iodine) and maintains specific ratios between novolac resin and halogen-containing compounds (10:1 to 1:1 by mass). This parameter optimization achieves high etching rates while preventing excessive halogen content that would cause intermixing with the resist film

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The underlayer composition is designed with localized functional distribution: novolac resin provides structural stability and adhesion, while halogen-containing compounds are distributed to provide etching enhancement. This local quality differentiation allows the film to achieve high etching rates in specific regions without compromising overall film integrity or causing resist intermixing

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP4692942A1Composition for forming resist underlayer film

Publication Date: 2026.02.11 NISSAN CHEM CORP

AI summary

A resist underlayer film-forming composition comprising: a novolac resin (A) having a phenolic hydroxy group and a halogen atom directly bonded to an aromatic hydrocarbon ring; and a solvent (B).