Fluoroalcohol Resist Polymer for High-Resolution Negative Patterning
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Solution Overview
Problem
Current negative pattern formation techniques via organic solvent development face challenges in achieving high resolution and etch resistance, particularly at finer sizes, due to issues like pattern bridging, collapse, and footing, and are limited by the use of expensive organic solvents and the need for robust protective groups.
Innovation Solution
A resist composition featuring a polymer with recurring units derived from a specific monomer capable of polarity switching under acid action, which forms a negative pattern insoluble in alkaline developers and exhibits high etch resistance, utilizing a base resin with a fluoroalcohol structure that changes solubility upon exposure, thereby preventing pattern distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative pattern formation is performed via organic solvent development to improve resolution, then pattern resolution is improved, but etch resistance deteriorates due to loss of carbon density and protective groups
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the polymer to include fluoroalcohol units with specific properties. The fluoroalcohol-containing recurring units maintain alkaline solubility while providing inherent etch resistance through their molecular structure, eliminating the need for robust protective groups like cyclic structures that would compromise resolution
Solution Approach 2:
The patent uses composite materials by creating a copolymer consisting of fluoroalcohol-containing recurring units and other recurring units with specific properties. This composite polymer structure combines the alkaline solubility needed for high-resolution negative pattern formation with the etch resistance provided by the fluoroalcohol units, achieving both improved resolution and maintained etch resistance simultaneously
2Strength
If robust protective groups such as cyclic structures are incorporated to improve etch resistance, then etch resistance is improved, but pattern resolution deteriorates due to swelling and collapse
Solution Approach 1:
The patent changes the parameter of etch resistance mechanism from relying on robust protective groups to relying on fluoroalcohol units that provide etch resistance through their chemical structure while maintaining pattern integrity. The fluoroalcohol units do not cause swelling or collapse, thereby preserving pattern resolution
Solution Approach 2:
The patent replaces expensive and problematic robust protective groups with simpler fluoroalcohol units that achieve the same etch resistance function without the side effects of swelling and collapse, effectively using a simpler, more efficient structural element
3Strength
If crosslinking reaction is used to improve etch resistance, then etch resistance is improved, but pattern distortion occurs due to bridging and collapse
Solution Approach 1:
The patent changes the approach to achieving etch resistance from crosslinking reactions to the inherent properties of fluoroalcohol-containing recurring units. This parameter change eliminates the need for crosslinking while maintaining etch resistance and preventing pattern distortion
Solution Approach 2:
The patent extracts the etch resistance function from the crosslinking mechanism and places it directly into the fluoroalcohol unit structure, eliminating the harmful crosslinking process while preserving the beneficial etch resistance property
4Ease of operation
If polarity switch groups such as tertiary hydroxyl groups are used to improve alkaline solubility, then alkaline solubility is improved, but dissolution rate difference becomes insufficient causing footing
Solution Approach 1:
The patent changes the polarity switch group from tertiary hydroxyl groups to fluoroalcohol units. This parameter change provides sufficient dissolution rate difference between exposed and unexposed regions while maintaining good alkaline solubility, preventing footing and achieving proper pattern profile
Solution Approach 2:
The patent replaces complex polarity switch groups with simpler fluoroalcohol units that achieve the same solubility control function with better performance, eliminating footing issues while maintaining ease of operation
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 solution enables the formation of high-resolution, alkaline-developable negative patterns with improved etch resistance and reduced swell, effectively addressing the limitations of existing methods by maintaining pattern integrity and reducing the need for expensive organic solvents.
Implementation Method 1
a polymer having recurring units derived from a monomer of formula (1a) or (1b)... capable of polarity switching under acid action... which forms a negative pattern insoluble in alkaline developers
Implementation Method 2
utilizing a base resin with a fluoroalcohol structure that changes solubility upon exposure
Implementation Method 3
exhibits high etch resistance... maintaining pattern integrity... addressing the limitations of existing methods
Data Source
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AI summary
A monomer having a substituent group capable of polarity switch under the action of acid is provided. A useful polymer is obtained by polymerizing the monomer. A resist composition comprising the polymer has improved development properties and is processed to form a negative pattern having high resolution and etch resistance which is insoluble in alkaline developer.