Positive Resist Composition for Fine Pattern Formation
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Solution Overview
Problem
Conventional resist compositions face challenges in forming fine patterns with narrow pitches, particularly in lithography techniques, where pattern collapse occurs due to changes in light irradiation during mask size adjustments, leading to deteriorated circularity of holes and other pattern shape issues.
Innovation Solution
A positive resist composition is developed, incorporating a polymeric compound with specific structural units that include an acid dissociable, dissolution inhibiting group and a lactone-containing cyclic group, which increases solubility in an alkali developing solution upon exposure, allowing for improved pattern formation and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional resist compositions are used for fine pattern formation, then lithography processes can be performed, but pattern collapse occurs and circularity deteriorates due to changes in light irradiation during mask size adjustments
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist material by incorporating specific polymeric compounds with acid dissociable groups and lactone-containing cyclic groups. These compositional changes enable the resist to maintain stable solubility characteristics during development, preventing pattern collapse and improving circularity without requiring changes to the lithography equipment or process conditions
Solution Approach 2:
The patent creates a composite resist system by combining multiple functional components: polymeric compounds with acid dissociable dissolution inhibiting groups, lactone-containing cyclic groups for adhesion enhancement, and other auxiliary components. This composite structure provides both the necessary light sensitivity and the mechanical stability required for precise fine pattern formation, resolving the contradiction between pattern formation capability and pattern stability
2Measurement precision
If mask size is adjusted to form fine patterns with narrow pitches, then resolution improves, but pattern collapse occurs due to changes in light irradiation
Solution Approach 1:
The patent changes the chemical parameters of the resist material by incorporating polymeric compounds with specific functional groups that provide stable solubility characteristics. This allows the resist to maintain its physical integrity during development even when forming fine patterns with narrow pitches, preventing pattern collapse and maintaining both resolution and pattern shape accuracy
Solution Approach 2:
The acid dissociable dissolution inhibiting groups act as intermediary elements that mediate between the exposed and unexposed regions during development. These groups provide controlled solubility differences that allow fine pattern formation while preventing excessive dissolution that would lead to pattern collapse, thus maintaining both resolution and shape accuracy
3Ease of operation
If resist material solubility is increased for better development, then exposed portions become more soluble, but unexposed portions may also dissolve causing pattern distortion
Solution Approach 1:
The patent applies the concept of local quality by using acid dissociable dissolution inhibiting groups that are selectively activated in exposed regions. In unexposed regions, these groups remain intact and prevent dissolution, while in exposed regions, acid generation causes dissociation and increases solubility. This localized difference in solubility characteristics enables efficient development while maintaining pattern shape fidelity
Solution Approach 2:
The patent utilizes parameter changes in the chemical state of the dissolution inhibiting groups. The groups transition from a non-dissociated state (insoluble) in unexposed regions to a dissociated state (soluble) in exposed regions due to acid generation. This parameter change enables selective development with high efficiency while preventing pattern distortion
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 effectively forms resist patterns with enhanced resolution, circularity, and stability, particularly in the nano-scale, by maintaining solubility differences between exposed and unexposed areas, thus addressing pattern collapse issues.
Implementation Method 1
an acid generator that generates acid upon exposure. If the resist film formed using the resist composition is selectively exposed during formation of a resist pattern, then within the exposed portions, acid is generated from the acid generator
Data Source
AI summary
A positive resist composition including a base component (A) which exhibits increased solubility in an alkali developing solution under action of acid and an acid-generator component (B) which generates acid upon exposure, the base component (A) including a polymeric compound (A1′) containing an acid dissociable, dissolution inhibiting group within the structure thereof and including a structural unit (a0) represented by general formula (a0-1) (R2 represents a divalent linking group, and A″ represents an oxygen atom, a sulfur atom, or an alkylene group of 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom) and a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group; or a polymeric compound (A1) including the structural unit (a0) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.