Rinse Liquid for Lithography Preventing Pattern Collapse
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Solution Overview
Problem
Existing rinse solutions for lithography fail to effectively prevent both pattern collapse and melting of fine resist patterns, particularly in miniaturized ArF and deep UV resist patterns, despite the use of nitrogen-containing compounds and nonionic surfactants.
Innovation Solution
A rinse solution comprising a nitrogen-containing compound, such as N,N,N',N'-tetramethylethylenediamine, and a nonionic surfactant with an alkyleneoxy group, combined with water and optionally other additives, is used to treat the resist pattern, improving surface tension and wettability to prevent pattern collapse and melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pure water is used to wash the resist pattern after development, then the washing is simple and effective, but the surface tension of pure water applies negative pressure on the pattern causing pattern collapse
Solution Approach 1:
The patent changes the chemical composition parameters of the rinse solution by adding nitrogen-containing compounds and nonionic surfactants to pure water. This modifies the surface tension and wettability parameters of the rinse solution, allowing it to wet the resist pattern surface effectively while reducing surface tension-induced negative pressure, thereby preventing pattern collapse during the rinsing process
Solution Approach 2:
The nitrogen-containing compound and nonionic surfactant act as intermediary substances between the aqueous rinse solution and the resist pattern. These intermediaries modify the interface properties, improving wettability and reducing surface tension effects that would otherwise cause pattern collapse, enabling effective rinsing without compromising pattern integrity
2Ease of operation
If conventional rinse solutions are used, then the rinsing process is simple, but they fail to prevent both pattern collapse and melting of fine resist patterns
Solution Approach 1:
The patent creates a composite rinse solution by combining pure water with nitrogen-containing compounds and nonionic surfactants. This composite formulation integrates multiple functional components: water provides the rinsing medium, nitrogen-containing compounds contribute to surface tension reduction and chemical interaction with carboxylic acid groups, and nonionic surfactants enhance wettability. Together, they provide comprehensive protection against both pattern collapse and melting while maintaining operational simplicity
Solution Approach 2:
The rinse solution is designed to provide locally optimized properties at the resist pattern surface interface. The nitrogen-containing compounds and nonionic surfactants concentrate at the interface, providing localized surface tension reduction and enhanced wettability exactly where needed, while the bulk solution maintains its rinsing function. This local quality enhancement protects fine resist patterns without complicating the overall rinsing process
3Manufacturing precision
If the resist pattern is miniaturized to increase integration degree, then the pattern fineness is improved, but pattern collapse and pattern roughness become more severe
Solution Approach 1:
The patent modifies the physical-chemical parameters of the rinse solution, specifically surface tension and wettability, by incorporating nitrogen-containing compounds and nonionic surfactants. These parameter changes are critical for miniaturized patterns which have higher surface area to volume ratios and are more susceptible to surface tension effects. The modified rinse solution parameters provide adequate support and reduced capillary pressure on fine patterns, preventing collapse and roughness while maintaining the achieved pattern fineness
Solution Approach 2:
The nitrogen-containing compounds and nonionic surfactants in the rinse solution provide beforehand cushioning protection to miniaturized resist patterns. By pre-modifying the rinse solution composition to have reduced surface tension and improved wettability, the solution is prepared in advance to gently handle the delicate fine patterns during rinsing, cushioning them against collapse and roughness that would otherwise occur due to their small dimensions
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 prevents pattern collapse and melting, enabling the formation of precise and accurate high-aspect-ratio resist patterns, even at fine dimensions, by combining with carboxylic acid groups to reduce solubility in aqueous solutions.
Implementation Method 1
combining with carboxylic acid groups to reduce solubility in aqueous solutions
Implementation Method 2
improving surface tension and wettability to prevent pattern collapse
Implementation Method 3
improving surface tension and wettability to prevent pattern collapse
Data Source
AI summary
The present invention provides a rinse solution for lithography and a pattern formation method using the solution. They can improve prevention of both the pattern collapse and the melting at the same time. The solution contains water and a particular nitrogen-containing compound having an organic group, such as, alkyl amine or the like. The rinse solution may further contain a nonionic surfactant, if necessary.