Negative Development Resist Composition Acid Diffusion Control
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Solution Overview
Problem
Current negative developing processes for resist patterns using chemically amplified resist compositions face challenges in achieving high lithography properties due to acid diffusion from exposed areas affecting unexposed regions, particularly when using bright masks, which limits the resolution and contrast of trench and hole patterns.
Innovation Solution
A resist composition for negative development is developed, comprising a base component with decreased solubility in organic solvents under acid action and an acid generator that produces an acid with a log P value of 2.7 or less and a pKa value of at least −3.5, allowing for precise control of acid generation and diffusion, thereby improving lithography properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acid generators are used in negative developing process, then exposure sensitivity is achieved, but acid diffusion from exposed areas to unexposed regions occurs, deteriorating lithography properties and pattern resolution
Solution Approach 1:
The patent applies parameter changes by selecting acid generators with specific pKa values (−6 or lower) and log P values (3.0 or higher). This changes the chemical parameters of the acid generation system to achieve a balance where sufficient acid is generated for crosslinking in exposed areas while limiting excessive acid diffusion to unexposed regions, thereby resolving the contradiction between exposure sensitivity and pattern resolution.
Solution Approach 2:
The patent uses composite materials by combining the base component (acrylic resin with carboxyl groups) with specifically selected acid generators (onium salts or sulfonium salts having defined pKa and log P values). This composite resist composition creates a synergistic effect where the base component provides the matrix and the acid generator provides controlled acid generation, achieving both sensitivity and resolution while minimizing harmful acid diffusion.
2Productivity
If bright masks are used to improve pattern formation, then exposure efficiency increases, but acid diffusion affects unexposed portions, reducing contrast and resolution
Solution Approach 1:
The patent changes the parameters of the acid generator (pKa ≤ −6 and log P ≥ 3.0) to optimize the acid generation characteristics. This allows the use of bright masks for efficient exposure while the modified acid generation parameters ensure that acid diffusion does not compromise pattern contrast, thus resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent applies local quality by creating different chemical properties in exposed versus unexposed regions through controlled acid generation. The acid generator is designed to produce acid locally in exposed areas that triggers crosslinking, while the specific log P value limits the range of diffusion, thereby maintaining local contrast even when using bright masks for high productivity.
3Reliability
If acid generation is increased to improve crosslinking in exposed areas, then pattern definition improves, but acid diffusion to unexposed areas increases, reducing solubility difference and pattern quality
Solution Approach 1:
The patent changes the chemical parameters of the acid generator to achieve optimal acid generation control. By selecting acid generators with pKa ≤ −6 and log P ≥ 3.0, sufficient acid is generated in exposed areas to ensure complete crosslinking and pattern definition, while the log P parameter controls the diffusion range to preserve solubility differences between exposed and unexposed regions, thus resolving the contradiction between reliability and compositional stability.
Solution Approach 2:
The patent effectively copies the exposure pattern through controlled acid generation and crosslinking. The acid generator creates a chemical copy of the exposed pattern by generating acid only in exposed areas, and the specific pKa/log P parameters ensure this copy is accurate without excessive diffusion that would blur the solubility contrast between exposed and unexposed regions.
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 enables the formation of resist patterns with enhanced resolution and contrast, particularly for trench and hole patterns, by controlling acid diffusion and maintaining solubility differences between exposed and unexposed areas, thus improving the overall lithography performance.
Implementation Method 1
an acid generator component (B) which generates acid upon exposure
Implementation Method 2
a base component (A) which exhibits decreased solubility in an organic solvent under the action of acid
Implementation Method 3
a base component (A) which exhibits decreased solubility in an organic solvent under the action of acid
Data Source
AI summary
A resist composition for negative development including a base component (A) which exhibits decreased solubility in an organic solvent under the action of acid and an acid generator component (B) which generates acid upon exposure; and the resist composition used in a method of forming a resist pattern which includes: forming a resist film on a substrate using the resist composition; conducting exposure of the resist film; and patterning the resist film by negative development using a developing solution containing the organic solvent to form a resist pattern, wherein the acid generator component (B) contains an acid generator (B1) that generates an acid having a log P value of 2.7 or less and also a pKa value of at least −3.5.