EUV Photoresist Processing Solution for Micro-Bridge Defect Reduction

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Solution Overview

Problem

The challenge in semiconductor manufacturing is the high incidence of micro-bridge defects and Line Width Roughness (LWR) during extreme-ultraviolet lithography, which hampers the formation of fine patterns and reduces processing margins.

Innovation Solution

A processing solution composition comprising 0.0001 to 1 wt% of a nonionic surfactant with an HLB value of 9 to 16 and 98 to 99.9998 wt% of water, using alkaline materials like tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, is developed to reduce micro-bridge defects and LWR in polyhydroxystyrene-containing photoresist patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional photoresist is used for EUV lithography, then the basic patterning function is achieved, but micro-bridge defects and LWR increase significantly

Engineering Contradiction:
Improvepattern uniformityVSAvoiddefect incidence
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the photoresist system by introducing a specific post-exposure bake (PEB) treatment at 90-110°C for 30-120 seconds, and uses a multi-component developer solution with controlled concentrations of TMAH (0.1-10 wt%) and surfactants (0.01-1 wt%), thereby achieving reduced micro-bridge defects and LWR without fundamentally changing the photoresist material itself

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a surfactant as an intermediary substance in the developer solution that mediates between the hydrophobic photoresist pattern and the aqueous developer, improving wetting uniformity and reducing surface tension-induced defects, thereby simultaneously improving pattern uniformity and reducing defect incidence

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If the photoresist pattern is made finer to achieve smaller features, then the minimum feature size is reduced, but the processing margin decreases and defects increase

Engineering Contradiction:
Improveminimum feature sizeVSAvoidprocessing margin
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent adjusts the PEB temperature parameter to 90-110°C (optimized range) and the developer composition parameters (TMAH concentration 0.1-10 wt%, surfactant concentration 0.01-1 wt%) to create a processing window that maintains sufficient processing margin even for finer patterns, thereby enabling smaller feature sizes without proportionally increasing defects

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a strong surfactant with high lipophilicity is used in the developer, then the affinity for hydrophobic photoresist is improved, but agglomeration occurs and defects are caused

Engineering Contradiction:
Improveaffinity for photoresistVSAvoidsolution uniformity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the surfactant concentration parameter to a low range (0.01-1 wt%) and selects surfactants with balanced HLB values (4-18), thereby achieving sufficient affinity for hydrophobic photoresist patterns while preventing agglomeration and maintaining solution uniformity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies surfactant functionality locally at the photoresist-developer interface rather than requiring high bulk concentration, using small amounts of surfactant (0.01-1 wt%) that concentrate at the interface to provide sufficient wetting improvement without causing bulk phase separation or agglomeration

Inventive Principle:
Principle #3Local quality

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 solution effectively decreases micro-bridge defects and LWR, improving pattern uniformity and reducing production costs by preventing pattern collapse during extreme-ultraviolet exposure.

Implementation Method 1

an effective cleaning solution is prepared using a nonionic surfactant having an HLB value of 9 to 16

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Implementation Method 2

the affinity for the hydrophobic photoresist to be cleaned is poor

Methodology Applied
Scientific EffectWetting: Wetting

Implementation Method 3

0.0001 to 1 wt% of an alkaline material

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS11624984B2Process liquid composition for extreme ultraviolet lithography and pattern forming method using same
Publication Date: 2023.04.11 YOUNG CHANG CHEMICAL CO LTD

AI summary

A processing solution composition for reducing micro-bridge defects in a polyhydroxystyrene-containing photoresist pattern defined by an extreme-ultraviolet exposure source and a method of forming a pattern using the same are proposed. The processing solution composition includes 0.0001 to 1 wt % of an alkaline material, 0.0001 to 1 wt % of a nonionic surfactant having an HLB (Hydrophilic-Lipophilic Balance) value of 9 to 16, and 98 to 99.9998 wt % of water, reduces the number of micro-bridge defects in a polyhydroxystyrene-containing photoresist pattern defined by an extreme-ultraviolet exposure source, and has a low LWR (Line Width Roughness) value, thus effectively improving the uniformity of the pattern.