Amine Oxide Resist Composition for Deep-UV Lithography
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Solution Overview
Problem
Chemically amplified positive resists used in deep-UV lithography face issues such as 'T-top' shape defects, footing on substrates, and dimensional control challenges due to post-exposure delay and acid labile group elimination, which affect pattern resolution and etch resistance.
Innovation Solution
Incorporating a compound with an amine oxide structure as a basic component in the resist composition, along with an organic solvent, a base resin with acid labile groups, and a photoacid generator, to enhance resolution and prevent pattern collapse during development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chemically amplified positive resist is used for deep-UV lithography, then sensitivity and resolution are improved, but post-exposure delay causes T-top shape defects and dimensional control is lost
Solution Approach 1:
The patent applies preliminary action by adding a basic compound to the resist composition before exposure to preemptively neutralize airborne acids and prevent post-exposure delay effects. This preliminary chemical protection maintains pattern dimensional integrity throughout the exposure-to-development interval, preventing T-top defects while preserving the high resolution benefits of chemically amplified resists
2Reliability
If standing time from exposure to post exposure bake is extended, then acid diffusion and reaction completeness are improved, but line pattern acquires T-top shape and dimensional control is lost
Solution Approach 1:
The basic compound acts as an intermediary substance that mediates between the photo-generated acid and the resist polymer. It provides controlled acid neutralization during the standing time, allowing sufficient reaction completeness for reliable pattern transfer while preventing excessive acid diffusion that causes T-top shaping. This intermediary chemical maintains pattern profile integrity throughout the exposure-to-PEB interval
3Loss of time
If basic compounds are added to check airborne bases, then PED is reduced, but pattern profile control becomes difficult and etch resistance decreases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the concentration and basicity strength of the added basic compound. By optimizing these parameters, the resist achieves effective PED suppression through airborne base neutralization while maintaining adequate pattern profile control and etch resistance. The specific parameter range of basic compound concentration balances chemical protection against excessive profile modification
4Ease of manufacture
If acid labile groups are eliminated during dark reaction, then pattern development is improved, but final pattern dimensions are reduced
Solution Approach 1:
The basic compound provides preliminary anti-action by preemptively neutralizing photo-generated acid before it can cause excessive elimination of acid labile groups during the dark reaction. This preliminary chemical protection prevents over-development and dimensional shrinkage while still allowing sufficient group elimination for adequate pattern development contrast and clarity
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 resist composition achieves high resolution and improved etch resistance, preventing line pattern collapse and maintaining precise pattern profiles, making it suitable for microfabrication and photomask production.
Implementation Method 1
a chemically amplified positive resist composition comprising (A) a compound having an amine oxide structure as a basic component, (B) an organic solvent, (C) a base resin having an acid labile group-protected acidic functional group which is alkali-insoluble or substantially alkali-insoluble, but becomes alkali-soluble when the acid labile group is eliminated, and (D) a photoacid generator
Data Source
AI summary
A chemically amplified positive resist composition comprises a compound having an amine oxide structure as a basic component, a base resin, a photoacid generator, and an organic solvent. The resist composition exhibits a high resolution, significantly prevents a line pattern from collapsing after development, and has improved etch resistance.