Resist Composition Film Shrinkage Reduction via Acid-Labile Groups
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Solution Overview
Problem
Current resist compositions face challenges in achieving high dissolution contrast and reducing film shrinkage after post-exposure baking (PEB), which leads to deformation of isolated trench patterns during negative tone development, particularly in organic solvent development processes.
Innovation Solution
A resist composition is developed using a polymer compound with repeating units substituted with acid-labile groups, specifically (meth)acrylic acid derivatives, which improves dissolution contrast and reduces film shrinkage by controlling acid diffusion and adhesion to the substrate, combined with an acid generator and optional additives like basic compounds and surfactants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional resist composition is used for negative tone development, then dissolution contrast can be achieved, but film shrinkage occurs after PEB causing deformation of isolated trench patterns
Solution Approach 1:
The patent changes the chemical parameters of the resist composition by introducing a specific polymer compound with carboxyl groups that have pKa values between 3.5-5.5. This parameter change in the chemical composition allows the resist to achieve high dissolution contrast while reducing film shrinkage during PEB, thereby preventing pattern deformation without sacrificing manufacturing precision
Solution Approach 2:
The patent creates a composite resist composition by combining the specific polymer compound (with carboxyl groups of pKa 3.5-5.5) with other resist components including basic compounds and surfactants. This composite material approach enables the system to simultaneously achieve high dissolution contrast for pattern definition and reduced film shrinkage for pattern stability
2Measurement precision
If acid-labile groups are added to improve dissolution contrast, then resolution improves, but film shrinkage increases causing pattern deformation
Solution Approach 1:
The patent precisely controls the pKa parameter of the carboxyl groups to be between 3.5-5.5, which optimizes the balance between dissolution contrast and film shrinkage. This specific parameter range ensures that the acid-labile groups provide sufficient resolution while minimizing excessive film shrinkage that would cause pattern deformation
Solution Approach 2:
The patent introduces carboxyl groups with specific pKa values at localized positions within the polymer structure. This local quality modification allows different regions of the resist film to exhibit appropriate dissolution behavior and shrinkage resistance, achieving both high resolution and pattern stability
3Manufacturing precision
If basic compounds are added to neutralize acid, then dissolution contrast improves, but etching resistance decreases
Solution Approach 1:
The patent carefully controls the type and amount of basic compounds added to the resist composition. By adjusting these parameters, the system achieves sufficient dissolution contrast for pattern formation while maintaining adequate etching resistance during subsequent processing steps
Solution Approach 2:
The patent applies partial neutralization by adding basic compounds in controlled amounts that provide sufficient dissolution contrast without completely neutralizing the acid. This partial action maintains the necessary etching resistance while achieving the required dissolution contrast for high-quality pattern formation
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, excellent pattern profile, and reduced edge roughness, preventing deformation of isolated trench patterns and enhancing etching resistance, making it suitable for fine pattern formation in photomask and VLSI applications.
Implementation Method 1
controlling acid diffusion
Implementation Method 2
adhesion to the substrate
Data Source
AI summary
The present invention provides a resist composition containing a base resin composed of a polymer compound having a repeating unit in which a hydrogen atom of a carboxyl group is substituted with one or more acid-labile groups selected from groups shown by the following general formulae (1-1) to (1-5),wherein R1 to R5 represent a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or an alkynyl group having 2 to 4 carbon atoms; R6 represents a hydroxyl group or an alkoxy group or acyloxy group having 1 to 6 carbon atoms; and “m” represents 1 or 2. There can be provided a resist composition that can improve the dissolution contrast of a resist film and reduce the film shrinkage after PEB, and a patterning process using the same.