Quaternary Ammonium Hydroxide Developer for Lithography Pattern Uniformity

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Solution Overview

Problem

The semiconductor industry faces challenges in achieving uniformity of resist patterns during lithography processes, leading to line edge roughness (LER) and line width roughness (LWR) issues, which affect the quality and performance of integrated circuits, particularly in nanometer fabrication regimes.

Innovation Solution

The use of an alkaline aqueous developer solution with a quaternary ammonium hydroxide as an organic base, featuring bulky side chains to reduce penetration strength and basicity, which minimizes etching depth randomness and swelling, resulting in smoother resist patterns with reduced LER and LWR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional developer solutions are used for resist development, then the development process is simple and fast, but line edge roughness (LER) and line width roughness (LWR) increase, reducing pattern uniformity

Engineering Contradiction:

Improvepattern uniformityVSAvoiddeveloper composition complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent modifies the chemical parameters of the developer solution by using quaternary ammonium hydroxide with specific bulky side chains (R1, R2, R3, R4) instead of conventional developer components. This parameter change in the developer composition reduces penetration strength and minimizes etching depth randomness, thereby improving pattern uniformity and reducing LER/LWR while maintaining a relatively simple development process

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite developer solution comprising quaternary ammonium hydroxide with bulky side chains combined in specific concentrations (0.1-5% by weight). This composite chemical formulation works synergistically to reduce both penetration strength and basicity effects, achieving superior pattern uniformity that neither component could achieve alone

Inventive Principle:

Principle #40Composite materials

2Productivity

If developer with high penetration strength is used, then development speed is fast, but etching depth randomness increases, worsening LER and LWR

Engineering Contradiction:

Improvedevelopment speedVSAvoidetching depth uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the penetration strength parameter of the developer by selecting quaternary ammonium hydroxide with bulky side chains (R1-Z1, R2-Z2, R3-Z3, R4-Z4) that physically limit developer molecule penetration into the resist. This parameter modification reduces etching depth randomness and improves etching uniformity while maintaining adequate development speed through optimized concentration (0.1-5% by weight)

Inventive Principle:

Principle #35Parameter changes

3Productivity

If developer with high basicity is used, then resist etching efficiency is high, but resist swelling increases, worsening pattern uniformity

Engineering Contradiction:

Improveetching efficiencyVSAvoidpattern uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent modifies the basicity parameter of the developer by using quaternary ammonium hydroxide with bulky side chains that reduce the basicity effect on resist swelling. The specific molecular structure with bulky R groups (where at least one has van der Waals volume > ethylene group) limits the developer's ability to cause resist swelling while maintaining etching efficiency through optimized concentration ranges

Inventive Principle:

Principle #35Parameter changes

4Productivity

If scaling down process continues to increase functional density, then production efficiency increases and costs decrease, but LER and LWR become more critical and difficult to control

Engineering Contradiction:

Improveproduction efficiencyVSAvoidLER and LWR control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes in the developer composition (quaternary ammonium hydroxide with bulky side chains at 0.1-5% concentration) that specifically address LER and LWR control. This enables continued scaling down to 10nm and beyond by providing the precision needed for smaller feature sizes while maintaining the production efficiency and cost benefits of scaling

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 proposed developer solution significantly improves the uniformity of resist patterns, reducing LER and LWR, thereby enhancing the quality and performance of semiconductor devices, especially in advanced process nodes like 10 nanometer and beyond.

Implementation Method 1

removing a portion of the exposed material layer in a developer, resulting in a patterned material layer. The developer is an alkaline aqueous solution having an organic base that is a quaternary ammonium hydroxide

Methodology Applied

Scientific EffectChemical etching:

Data Source

PatentUS11774855B2Lithography patterning technique

Publication Date: 2023.10.03 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A lithography developing composition includes an alkaline aqueous solution having a quaternary ammonium hydroxide with both a steric functional group and an electron withdrawing group on its side chains.