Polymer Resist Composition with Bound Acid Generator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge lies in synthesizing a polymer with an acid generator bound to its backbone in a consistent and reproducible manner, while preventing decomposition during polymerization, which affects the stability and sensitivity of resist compositions used in microelectronic device manufacturing, particularly at higher accelerating voltages and smaller feature sizes.
Innovation Solution
The polymerization of monomers is conducted under illumination conditions where light of wavelength up to 400 nm is substantially cut off, using LED or organic EL lamps to inhibit photo-decomposition of the acid generator and subsequent deprotection reactions, ensuring the formation of a stable polymer suitable for both positive and negative resist compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the onium salt having polymerizable olefin is decomposed during polymerization to generate acid, then the acid generator function is activated, but deprotection of the acid labile group occurs during polymerization causing the unexposed region to dissolve in alkaline developer and fail to form a pattern
Solution Approach 1:
The patent applies preliminary protection by adding a basic compound to the polymerization solution before polymerization begins. This basic compound preemptively neutralizes any acid generated from onium salt decomposition during polymerization, preventing premature deprotection of acid labile groups. The basic compound acts as a preventive measure that ensures the acid labile groups remain intact until the actual exposure step, thereby maintaining pattern formation reliability while allowing the acid generator to be activated during polymerization.
2Manufacturing precision
If the accelerating voltage of the electron gun is increased from 10 kV to 50 kV to reduce pattern rule, then the resolution and dimensional control are improved, but the sensitivity of the resist film is reduced leading to reduced throughput
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the resist film to achieve higher sensitivity at high accelerating voltages. Specifically, the patent uses a polymer with acid labile groups that can be deprotected by weak acids, combined with an onium salt acid generator that decomposes during polymerization to generate acid. This chemical parameter modification enables the resist to respond more sensitively to the electron beam exposure, maintaining high throughput even at 50 kV accelerating voltage where resolution and dimensional control are improved.
3Area of moving object
If the feature size is reduced to increase integration density, then the storage capacity is increased, but image blurs due to acid diffusion become a problem reducing resolution
Solution Approach 1:
The patent applies local quality by creating spatially differentiated zones within the resist film with different acid generation characteristics. The onium salt is incorporated into the polymer structure such that acid is generated locally at the exposure sites during polymerization. This localized acid generation minimizes acid diffusion to surrounding unexposed regions, maintaining sharp pattern edges and high resolution even at reduced feature sizes for increased integration density.
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
This approach results in a polymer that maintains high dissolution contrast and rectangularity of patterns, suppresses agglomeration, and enhances the stability of the resist composition, enabling efficient pattern formation in semiconductor lithography and other applications.
Implementation Method 1
image blurs due to acid diffusion become a problem. To insure resolution for fine patterns with a size of 45 nm et seq., not only an improvement in dissolution contrast is important as previously reported, but control of acid diffusion is also important
Implementation Method 2
If the onium salt having polymerizable olefin is decomposed during polymerization, it generates an acid, with which deprotection of the acid labile group on the acid labile group-bearing recurring unit takes place
Implementation Method 3
As means for suppressing deprotection reaction during polymerization, Patent Document 6 proposes to add a basic compound to a polymerization solution prior to polymerization reaction
Data Source
AI summary
A polymer comprising recurring units having an acid generator bound to the backbone, and recurring units having an optionally acid labile group-substituted carboxyl group and/or recurring units having an optionally acid labile group-substituted hydroxyl group is obtained by polymerizing corresponding monomers under such illumination that the quantity of light of wavelength up to 400 nm is up to 0.05 mW/cm2. The polymer avoids photo-decomposition of the acid generator during polymerization and concomitant deprotection reaction of the acid labile group when used in positive resist compositions. A pattern with high dissolution contrast and rectangularity is formed after development.