Positive Resist Composition for Ultrafine Pattern Formation
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Solution Overview
Problem
Current resist pattern forming methods fail to achieve high sensitivity, high resolution, and small line edge roughness for ultrafine patterns with line widths of 30 nm or less, leading to pattern collapse and deterioration in LER performance.
Innovation Solution
A resist pattern forming method involving a positive resist composition with a specific polymer compound and alkali developer concentration, where the film thickness is between 15 to 40 nm, and the alkali developer concentration is between 0.5 to 1.1 mass %, with continuous supply during development, using electron beam or EUV light exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resist film is thinned to form ultrafine patterns with line widths of 30 nm or less, then the resolution is improved, but the pattern connection reliability deteriorates due to film loss during development
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by incorporating specific polymer compounds with acid-labile groups (acetal, orthoester, carbonate, carbamate) and controlling the ratio of acid-generating groups to acid-labile groups. This chemical parameter optimization enables the resist film to maintain structural integrity during development while achieving ultrafine pattern resolution of 30 nm or less, thereby resolving the contradiction between resolution improvement and pattern connection reliability
Solution Approach 2:
The patent creates a composite resist system by combining multiple functional components: polymer compounds with acid-labile groups, acid generators, and basic compounds. This composite material approach allows the resist film to exhibit both high resolution capability and enhanced pattern connection reliability during development, as the different components work synergistically to control film loss while maintaining ultrafine pattern definition
2Ease of manufacture
If conventional resist compositions and development conditions are used, then the process is simple, but the line edge roughness and resolution performance are insufficient for ultrafine patterns
Solution Approach 1:
The patent optimizes specific parameter ranges including the ratio of acid-generating groups to acid-labile groups (0.1 to 10 mol/mol), polymer compound molecular weight (1,000 to 100,000), and film thickness (10 to 50 nm). These parameter changes enable ultrafine pattern formation with reduced line edge roughness while maintaining process feasibility, balancing manufacturing precision improvement with ease of manufacture
Solution Approach 2:
The patent introduces local quality variations within the resist film through the spatial distribution of acid-labile groups and acid generators. The acid-labile groups are strategically positioned to provide localized solubility changes during development, enabling precise control over line edge formation and reducing line edge roughness while maintaining overall process simplicity
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 method achieves high sensitivity, high resolution, and excellent pattern profile with small line edge roughness, effectively addressing the limitations of existing techniques.
Implementation Method 1
a step of exposing the film; and a step of performing development by using an alkali developer after the exposing wherein the positive resist composition contains (A) a polymer compound having a repeating unit represented by formula (I) wherein each of n number of Y's independently represents a hydrogen atom or a group capable of leaving by an action of an acid
Data Source
AI summary
A resist pattern forming method includes: in the following order, (1) a step of forming a film on a substrate by using a positive resist composition; (2) a step of exposing the film; and (4) a step of performing development by using an alkali developer after the exposing, wherein the positive resist composition contains (A) a polymer compound having a repeating unit represented by the following formula (I) as defined in the specification, a thickness of the film formed in the step (1) is from 15 to 40 nm, and an alkali component concentration in the alkali developer is from 0.5 to 1.1 mass %.