Resist Composition for Organic Solvent Development
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Solution Overview
Problem
The existing negative tone resist composition for organic solvent development exhibits low dissolution contrast, leading to poor pattern formation with low gamma (γ) values, which results in inversely tapered profiles and pattern collapse, especially in line patterns, due to the low difference in dissolution rates between exposed and unexposed regions.
Innovation Solution
A resist composition comprising a polymer with recurring units of monocyclic lactone having alkyl groups and acid labile groups, combined with a photoacid generator, which enhances dissolution contrast through high lipophilicity and controlled acid diffusion, improving mask error factor (MEF) and critical dimension uniformity (CDU) during organic solvent development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative tone resist composition is used for organic solvent development, then fine hole patterns can be formed, but dissolution contrast is low resulting in poor pattern formation with low gamma values
Solution Approach 1:
The patent changes the chemical parameters of the resist composition by incorporating specific polymer units with acid-labile groups (acetal, orthoester, carbonate, carbamate) that dramatically alter dissolution behavior. This transforms the dissolution contrast from less than 100-fold to over 1000-fold difference between exposed and unexposed regions, enabling reliable negative tone patterning
Solution Approach 2:
The patent creates a composite resist system combining multiple polymer units with different functions: adhesive units (lactone, sultone), solubility control units (acid-labile groups), and structural units. This composite approach allows simultaneous optimization of adhesion, dissolution contrast, and pattern fidelity that cannot be achieved with single-component resists
2Ease of operation
If conventional negative tone resist is used, then organic solvent development is possible, but dissolution rate difference between exposed and unexposed regions is small (less than 100 times)
Solution Approach 1:
The patent introduces polymer units containing acid-labile groups that undergo rapid deprotection upon acid generation. This changes the dissolution parameter from slow and gradual (conventional <100x rate difference) to fast and abrupt (inventive >1000x rate difference), creating sharp dissolution fronts that define precise pattern edges
Solution Approach 2:
The acid-labile groups act as intermediaries that translate the subtle chemical changes from photoacid generation into dramatic dissolution rate differences. These groups serve as amplifiers that convert small amounts of generated acid into large changes in polymer solubility, enabling high contrast development
3Productivity
If low dissolution contrast is accepted, then negative tone development can proceed, but gamma values are low causing inversely tapered profiles and pattern collapse
Solution Approach 1:
The patent changes the kinetic parameters of the dissolution process by incorporating acid-labile groups that rapidly deprotect upon acid generation. This transforms the dissolution profile from gradual and tapered (low gamma) to abrupt and uniform (high gamma), preventing pattern collapse while maintaining production throughput
Solution Approach 2:
The resist composition is pre-engineered with acid-labile groups positioned to deprotect at specific locations during exposure. This preliminary chemical preparation ensures that when development occurs, the dissolution contrast is already optimized to produce high gamma values and prevent pattern defects
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 dissolution contrast and improved resist performance factors such as MEF and CDU, enabling the formation of fine, round hole patterns with enhanced CDU, addressing the limitations of low contrast and pattern collapse in negative tone development.
Implementation Method 1
a photoacid generator
Implementation Method 2
deprotection reaction with the aid of acid
Implementation Method 3
development in an organic solvent to form a negative tone pattern in which the unexposed region of resist film is dissolved
Data Source
AI summary
A resist composition comprising a polymer comprising recurring units of lactone and a PAG is provided. The resist composition has a high dissolution contrast during organic solvent development, and improved resist properties including MEF and CDU and forms a fine hole pattern with improved roundness and size control.