Semiconductor Lithography Copolymer Acid Value Control

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Solution Overview

Problem

Current chemically amplified positive copolymers for semiconductor lithography lack high development contrast and resolution in fine-pattern formation, particularly when the acid value is reduced below a certain threshold, limiting their ability to form finer patterns with improved contrast.

Innovation Solution

A copolymer with repeating units having an alkali-soluble group protected by an acid-labile, dissolution-suppressing group, a lactone structure, and an alcoholic hydroxyl group, with an acid value of 0.01 mmol/g or less, achieved by precise acid value control using neutralization titration with alkali metal hydroxide and Bromothymol Blue as an indicator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the acid value of the copolymer is reduced to improve development contrast, then the development contrast improves, but the manufacturing precision deteriorates due to difficulty in controlling such low acid values

Engineering Contradiction:

Improvedevelopment contrastVSAvoidacid value control

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by modifying the acid value to an extremely low level (0.01 mmol/g or less), which is a significant deviation from conventional acid values. This parameter change enables high development contrast while the specific measurement method using Bromothymol Blue ensures accurate control at this extreme parameter level

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional acid value measurement methods with a specific titration method using Bromothymol Blue as an indicator. This substitution enables precise measurement and control of acid values at the extremely low level of 0.01 mmol/g or less, overcoming the limitations of conventional measurement techniques

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If conventional copolymers are used for ArF immersion lithography, then the process is simple, but the resolution and development contrast in fine-pattern formation are insufficient

Engineering Contradiction:

Improvelithography process simplicityVSAvoidfine-pattern resolution

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by reducing the acid value to 0.01 mmol/g or less, which fundamentally changes the chemical properties of the copolymer. This parameter change enables the copolymer to achieve high development contrast and excellent resolution in ArF immersion lithography while maintaining the simplicity of the lithography process

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a copolymer containing specific repeating units (alkali-soluble group protected by acid-labile dissolution-suppressing group, lactone structure, and alcoholic hydroxyl group) that work synergistically. This composite material structure achieves both high development contrast and excellent resolution while being compatible with conventional ArF immersion lithography processes

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 copolymer exhibits high development contrast and excellent resolution in fine-pattern formation, enabling the production of semiconductor devices with higher integration and improved lithography performance.

Implementation Method 1

a repeating unit having a structure which has an alkali-soluble group protected by an acid-labile, dissolution-suppressing group

Methodology Applied

Scientific EffectAcid-labile protection:

Implementation Method 2

a repeating unit having a lactone structure and having a polar group for enhancing the adhesivity to semiconductor substrate

Methodology Applied

Scientific EffectPolar group adhesion: Adhesive

Implementation Method 3

having an acid value of 0.01 mmol/g or less as determined by dissolving the copolymer in a solvent and subjecting the solution to neutralization titration with a solution of an alkali metal hydroxide using Bromothymol Blue as an indicator

Methodology Applied

Scientific EffectNeutralization titration:

Implementation Method 4

using Bromothymol Blue as an indicator

Methodology Applied

Scientific EffectIndicator color change:

Data Source

PatentUS8859180B2Copolymer and composition for semiconductor lithography and process for producing the copolymer

Publication Date: 2014.10.14 MARUZEN PETROCHEMICAL CO LTD

AI summary

[Task to Be Achieved]To provide a chemically amplified type positive copolymer for semiconductor lithography, which has eliminated the problems of prior art, has a high development contrast, and has excellent resolution in fine-pattern formation; a composition for semiconductor lithography which contains the copolymer; and a process for producing the copolymer.[Means for Achievement]The copolymer for semiconductor lithography according to the present invention is a copolymer which has at least (A) a repeating unit having a structure which has an alkali-soluble group protected by an acid-labile, dissolution-suppressing group, (B) a repeating group having a lactone structure and (C) a repeating group having an alcoholic hydroxyl group and which is characterized by having an acid value of 0.01 mmol/g or less as determined by dissolving the copolymer in a solvent and subjecting the solution to neutralization titration with a solution of an alkali metal hydroxide using Bromothymol Blue as an indicator.