Chemically Amplified Resist Composition for Immersion Lithography
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Solution Overview
Problem
Current chemically amplified resist compositions for immersion lithography face challenges in achieving optimal resolution and sensitivity, particularly when using ArF excimer lasers, due to limitations in etching resistance and line edge roughness, which are not adequately addressed by existing resin structures and acid generators.
Innovation Solution
A chemically amplified resist composition is developed, comprising a resin with specific structural units, including an acid-labile group and a polycyclic lactone structure, combined with a specific acid generator, which enhances solubility in organic solvents and alkali aqueous solutions, improving etching resistance and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional resin structures are used in chemically amplified resist compositions, then the composition can be manufactured with existing processes, but the resolution and sensitivity are insufficient for immersion lithography
Solution Approach 1:
The patent employs a composite resin system combining polycyclic lactone structural units (providing etching resistance and structural stability) with acid-labile group units (enabling chemical amplification and solubility control). This composite approach allows simultaneous achievement of high resolution through improved etching resistance and high sensitivity through acid-catalyzed solubility enhancement, resolving the contradiction between manufacturing precision and reliability in immersion lithography resist compositions.
2Strength
If resin structures for better etching resistance are used, then dry etching resistance is improved, but line edge roughness increases
Solution Approach 1:
The patent applies local quality by incorporating polycyclic lactone units specifically to provide etching resistance in regions requiring structural stability, while integrating acid-labile groups in side chains to ensure smooth solubility transitions during development. This localized functional distribution enables the resin to exhibit both high etching resistance and smooth line edges, as the acid-labile groups facilitate uniform deprotection and dissolution without causing roughness even when etching resistance is enhanced.
3Ease of operation
If the resin is made soluble in organic solvents, then the composition can be applied uniformly, but solubility in alkali aqueous solution is required for development
Solution Approach 1:
The patent implements preliminary action by incorporating acid-labile groups into the resin structure before exposure. During the exposure and post-exposure bake process, the acid generator produces protons that catalyze the cleavage of these labile groups, transforming the resin from an insoluble state in alkali to a soluble state. This pre-programmed chemical transformation enables the resin to maintain stability during application (soluble in organic solvents) while automatically becoming developable after exposure, resolving the contradiction between ease of operation and compositional stability.
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 composition provides improved resolution, sensitivity, and dry etching resistance, making it suitable for ArF excimer laser lithography and immersion lithography, as demonstrated by high-performance resist patterns and effective patterning capabilities.
Implementation Method 1
a structural unit having an acid-labile group in a side chain... which is soluble in an organic solvent and insoluble or poorly soluble in an alkali aqueous solution but rendered soluble in an alkali aqueous solution by the action of an acid; and an acid generator... wherein upon exposure to ultraviolet rays or extreme ultraviolet light, protons are produced
Data Source
AI summary
A chemically amplified resist composition, comprising: a resin which includes a structural unit having an acid-labile group in a side chain, a structural unit represented by the formula (I) and a structural unit having a polycyclic lactone structure, and which is soluble in an organic solvent and insoluble or poorly soluble in an alkali aqueous solution but rendered soluble in an alkali aqueous solution by the action of an acid; and an acid generator represented by the formula (II).wherein X1 represents a hydrogen atom, a C1 to C4 alkyl group, etc., Y in each occurrence independently represent a hydrogen atom or an alkyl group, and n is an integer of 1 to 14, R1 to R4 independently represent a hydrogen atom, an alkyl group, etc., and A+ represents an organic counterion, E− represents CF3SO3—, C2F5SO3—, C4F9SO3—, etc., Y1 and Y2 independently represent a fluorine atom or a C1 to C6 perfluoroalkyl group.