Fluorinated Ester Resist Compounds for Lithography Resolution
Solution Overview
Problem
Current resist materials for deep-ultraviolet lithography, particularly those using KrF or ArF excimer lasers, face challenges in achieving fine pattern rules due to inadequate acid-decomposition ability, thermal stability, and high outgassing, leading to issues like T-top patterns and dimensional changes during exposure and heat treatment.
Innovation Solution
Development of a novel ester compound with high acid-decomposition ability and thermal stability, incorporated into a polymer to form a resist composition that minimizes outgassing and enhances sensitivity and resolution, allowing for precise micropatterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If tert-butoxycarbonyl or tert-butyl groups are used as protective groups, then sensitivity is improved due to low reactivity with acids, but manufacturing precision deteriorates due to T-top patterns caused by acid deactivation
Solution Approach 1:
The patent changes the chemical parameters of the protective group by introducing fluorinated alkyl groups with specific chain lengths and branching structures. This modification alters the reactivity profile and thermal properties, enabling the protective group to maintain stability during exposure while preventing acid deactivation that causes T-top patterns, thus resolving the contradiction between sensitivity and manufacturing precision.
Solution Approach 2:
The patent creates a composite protective group structure combining fluorinated alkyl chains with carbonyl or carboxylate functionalities. This composite structure integrates the low reactivity needed for sensitivity with the thermal stability required to prevent dimensional changes, simultaneously addressing both conflicting requirements.
2Manufacturing precision
If 2-tetrahydropyranyl or 1-ethoxyethyl groups are used as protective groups, then manufacturing precision is improved by preventing T-top patterns, but sensitivity deteriorates due to high reactivity causing elimination reactions and dimensional changes
Solution Approach 1:
The patent modifies the protective group parameters by introducing fluorinated alkyl chains with controlled carbon numbers (1-6) and specific branching patterns. This parameter adjustment reduces the reactivity toward acid-catalyzed elimination while maintaining the structural integrity needed for dimensional stability, thereby improving sensitivity without sacrificing manufacturing precision.
3Manufacturing precision
If highly substituted polymers are used to prevent elimination reactions, then manufacturing precision is improved, but reliability deteriorates due to extreme drop of heat resistance
Solution Approach 1:
The patent changes the thermal parameters of the polymer by incorporating fluorinated alkyl groups with specific chain lengths and structures. These modifications enhance the thermal stability and heat resistance of the polymer backbone and side chains, ensuring that highly substituted polymers maintain both manufacturing precision and reliability under processing conditions.
Solution Approach 2:
The patent develops a composite polymer structure combining fluorinated alkyl-substituted protective groups with a stable polymer backbone. This composite material integrates the dimensional control benefits of high substitution with the heat resistance required for reliable processing, resolving the contradiction between manufacturing precision and reliability.
4Manufacturing precision
If 2-adamantyloxymethyl protective group is used, then manufacturing precision and sensitivity are improved, but object-generated harmful factors worsen due to formaldehyde outgassing causing lens contamination
Solution Approach 1:
The patent extracts the problematic formaldehyde-generating moiety from the protective group structure by replacing the 2-adamantyloxymethyl group with fluorinated alkyl-containing protective groups. This extraction eliminates the source of formaldehyde outgassing while preserving the beneficial properties of high sensitivity and manufacturing precision.
Solution Approach 2:
The patent changes the chemical composition parameters of the protective group by introducing fluorinated alkyl chains instead of the adamantyl structure. This parameter change eliminates formaldehyde generation during decomposition while maintaining the structural characteristics that provide high resolution and manufacturing precision.
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 novel ester compound-based resist composition achieves high sensitivity, resolution, and thermal stability, enabling the formation of fine-feature patterns with minimized outgassing, thereby addressing the limitations of existing materials.
Implementation Method 1
having a good acid-decomposition ability
Implementation Method 2
deep-ultraviolet lithography... KrF or ArF excimer laser as the light source
Data Source
AI summary
Novel ester compounds having formulae (1) to (4) wherein A1 is a polymerizable functional group having a carbon-carbon double bond, A2 is oxygen, methylene or ethylene, R1 is a monovalent hydrocarbon group, R2 is H or a monovalent hydrocarbon group, any pair of R1 and/or R2 may form an aliphatic hydrocarbon ring, R3 is a monovalent hydrocarbon group, and n is 0 to 6 are polymerizable into polymers. Resist compositions comprising the polymers as a base resin are thermally stable and sensitive to high-energy radiation, have excellent sensitivity and resolution, and lend themselves to micropatterning with electron beam or deep-UV.