Lithography Developer Formulation for Resist Swelling Control

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Solution Overview

Problem

Current positive tone development (PTD) developers in lithography cause resist swelling and pattern collapse due to high water content, while negative tone development (NTD) developers lack sufficient resist contrast, leading to high line edge roughness (LER) and line width roughness (LWR) issues in advanced semiconductor manufacturing processes.

Innovation Solution

A new PTD developer is formulated with a combination of organic solvent and basic solute, where the organic solvent constitutes more than 50% of the developer by weight, and the basic solute ranges from 0% to 30% by weight, along with reduced water content, to minimize resist swelling and enhance resist contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If basic aqueous developers are used in positive tone development (PTD) processes, then resist pattern formation is achieved, but resist swelling and pattern collapse issues occur

Engineering Contradiction:

Improveresist pattern qualityVSAvoidresist swelling and pattern collapse

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the developer by replacing water-based solvents with organic solvents (such as glycol ethers, ketones, or esters) and adjusting the concentration of basic compounds. This parameter change eliminates water-induced resist swelling while maintaining the alkaline conditions necessary for PTD chemistry, thereby resolving the contradiction between achieving resist pattern formation and avoiding resist swelling/collapse

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces organic solvents as intermediary substances that mediate between the developer's need for basic chemistry and the resist's sensitivity to water. These organic solvents provide the necessary chemical environment for development without causing the harmful swelling effects of water, thus acting as a mediator that resolves the contradiction

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If developers with organic solvent are used in negative tone development (NTD) processes, then resist swelling is reduced, but sufficient resist contrast is not provided

Engineering Contradiction:

Improveresist swellingVSAvoidresist contrast

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent creates a composite developer formulation that combines organic solvents with specifically selected basic compounds and additives. This composite approach allows the developer to simultaneously achieve low resist swelling (from the organic solvent) and high resist contrast (from the synergistic combination of basic compounds and additives), resolving the contradiction between reducing swelling and maintaining contrast

Inventive Principle:

Principle #40Composite materials

3Productivity

If water content in PTD developer is high, then developer effectiveness is maintained, but line edge roughness (LER) and line width roughness (LWR) increase

Engineering Contradiction:

Improvedeveloper effectivenessVSAvoidline edge roughness and line width roughness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent fundamentally changes the solvent parameter from water-based to organic-based, which alters the interaction mechanism between developer and resist. This parameter change maintains developer effectiveness through the basic chemistry of the organic solvent system while eliminating water-induced resist swelling that causes LER and LWR, thereby resolving the contradiction between developer effectiveness and pattern smoothness

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 new developer achieves low LER and LWR with high resist contrast, effectively addressing the limitations of traditional PTD and NTD developers in advanced lithography processes such as EUV and e-beam lithography.

Implementation Method 1

a new PTD developer is formulated with a combination of organic solvent and basic solute, where the organic solvent constitutes more than 50% of the developer by weight

Methodology Applied

Scientific EffectDissolution: Solvation

Data Source

PatentUS9927707B2Developer for lithography

Publication Date: 2018.03.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for lithography patterning includes forming a material layer over a substrate; exposing a portion of the material layer to a radiation; and removing the exposed portion of the material layer in a developer, resulting in a patterned material layer. The developer comprises water, an organic solvent, and a basic solute. In an embodiment, the basic solute is less than 30% of the developer by weight.