Chemically Amplified Resist Composition Acid Diffusion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chemically amplified resist compositions face challenges in achieving high resolution and minimizing line edge roughness (LER) due to uncontrolled acid diffusion during the pattern formation process, especially when using carboxylic acid onium salts or fluorocarboxylic acid onium salts in lithography.
Innovation Solution
A chemically amplified positive tone resist composition incorporating an onium salt compound with specific structural formulas and a resin adapted to increase solubility in alkaline developers, which effectively controls acid diffusion and enhances adhesion to substrates, thereby improving resolution and minimizing LER.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carboxylic acid onium salts or fluorocarboxylic acid onium salts are used in lithography, then sensitivity is improved, but acid diffusion becomes uncontrolled leading to increased LER and reduced resolution
Solution Approach 1:
A base compound is introduced as an intermediary substance that interacts with the acid generated from the onium salt. The base compound captures or neutralizes the diffused acid, preventing it from causing unwanted deprotection reactions in unexposed regions. This mediator approach allows the use of sensitive onium salts while controlling acid diffusion through the base compound's acid-capturing capability.
Solution Approach 2:
The patent modifies the chemical environment by introducing a base compound that changes the local pH parameters. This parameter change creates a chemical gradient that limits acid diffusion distance and controls the deprotection reaction spatial distribution, thereby improving resolution and reducing LER while maintaining sensitivity.
2Manufacturing precision
If acid diffusion is controlled by binding acid generators to base polymer, then LER is reduced, but solubility in organic solvent becomes problematic
Solution Approach 1:
The patent separates the acid generation function (onium salt) from the base polymer structure. Instead of binding them together, the onium salt is used as a free-standing component alongside a separately selected base compound. This segmentation maintains the solubility advantages of the base polymer while achieving LER reduction through the base compound's acid-capturing action.
Solution Approach 2:
A base compound serves as an intermediary that controls acid diffusion without being covalently bound to the polymer. This intermediary approach provides LER control while preserving the solubility properties of the base polymer in organic solvents, avoiding the solubility problems associated with bound acid generators.
3Productivity
If strong acid generators like sulfonium salts are used, then deprotection efficiency is improved, but deprotection occurs in unexposed regions due to acid diffusion
Solution Approach 1:
A base compound is introduced as a spatial controller that selectively captures diffused acid in unexposed regions. This intermediary allows strong acid generators to operate at full efficiency in exposed regions while preventing their acid from causing deprotection in unexposed regions, thereby maintaining pattern fidelity.
Solution Approach 2:
The patent creates local quality differences by using a base compound that establishes different chemical environments in exposed versus unexposed regions. In exposed regions, acid is generated and neutralized locally; in unexposed regions, the base compound captures any diffused acid, creating a sharp chemical boundary that preserves pattern fidelity while allowing efficient deprotection where needed.
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 and minimal LER in pattern formation, suitable for micropatterning processes like EUV or EB lithography, with the onium salt acting as an acid diffusion regulator to trap diffused acid and maintain contrast between exposed and unexposed regions.
Implementation Method 1
Upon exposure to high-energy radiation, the acid labile protective group is deprotected by the catalysis of an acid generated from a photoacid generator
Implementation Method 2
Since acid diffusion has a material impact on the sensitivity and resolution of a chemically amplified resist composition, many studies are made on the acid diffusion problem
Implementation Method 3
the acid labile protective group is deprotected by the catalysis of an acid generated from a photoacid generator so that the polymer may turn soluble in alkaline developer
Data Source
AI summary
A resist composition comprising a resin adapted to be decomposed under the action of acid to increase its solubility in alkaline developer and a sulfonium or iodonium salt of nitrogen-containing carboxylic acid has a high resolution. By lithography, a pattern with minimal LER can be formed.