Radiation-Sensitive Resist Composition With Low-Fluorine Photoacid Generator
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Solution Overview
Problem
Existing radiation-sensitive compositions used in photolithography for semiconductor devices face challenges in achieving high sensitivity, line width roughness (LWR) performance, depth of focus (DOF), pattern rectangularity, critical dimension uniformity (CDU), and pattern circularity while reducing environmental impact due to high fluorine content.
Innovation Solution
A radiation-sensitive composition comprising an onium salt compound with a specific structure, a polymer containing an acid-dissociable group, and a solvent, which generates a strong acid upon irradiation, enhancing sensitivity and controlling acid diffusion for improved LWR, DOF, pattern rectangularity, and CDU performance, while minimizing fluorine content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If perfluoroalkylsulfonic acid is used as a photoacid generator to improve sensitivity and resolution, then sensitivity and resolution are improved, but fluorine atom content increases causing environmental concerns
Solution Approach 1:
The patent changes the chemical parameters of the photoacid generator by using onium salts with specific structures (formula 1) that have reduced fluorine content compared to conventional perfluoroalkylsulfonic acid. The onium salt structure with controlled fluorine substitution maintains acid generation capability while reducing environmental harm.
Solution Approach 2:
The patent employs a composite approach by combining the onium salt compound (with specific R1, R2, A, and m1 parameters) with a polymer containing acid-dissociable groups. This composite resist composition achieves high resolution and sensitivity while controlling fluorine content through the specific molecular structure design.
2Measurement precision
If short-wavelength radiation is used to promote pattern micronization, then pattern resolution is improved, but sensitivity and manufacturing complexity increase
Solution Approach 1:
The patent optimizes the photoacid generator structure (onium salt with specific formula 1 parameters) to enhance sensitivity to short-wavelength radiation. The molecular structure is designed to absorb short-wavelength energy efficiently and generate sufficient acid for pattern formation, reducing the need for complex exposure systems.
3Object-affected harmful factors
If fluorine content is reduced to minimize environmental impact, then environmental friendliness is improved, but sensitivity and LWR performance may deteriorate
Solution Approach 1:
The patent carefully adjusts the fluorine content parameters in the onium salt structure (through selection of R1, R2, A groups and m1 value) to achieve an optimal balance. The structure maintains sufficient fluorine for sensitivity and LWR performance while reducing overall fluorine atom content compared to perfluoroalkylsulfonic acid, thereby improving environmental compatibility.
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 composition achieves high-quality resist patterns with excellent sensitivity, LWR performance, DOF, pattern rectangularity, and CDU, while reducing environmental impact by limiting fluorine usage.
Implementation Method 1
generating an acid by irradiating the coating of the resist composition with a radioactive ray through a mask pattern
Implementation Method 2
reacting in the presence of the acid as a catalyst to generate the difference of solubility of a polymer into an alkaline or organic developer between an exposed part and a non-exposed part
Implementation Method 3
a polymer including a structural unit which includes an acid-dissociable group
Data Source
AI summary
A radiation-sensitive composition includes: an onium salt compound represented by formula (1); a polymer including a structural unit which includes an acid-dissociable group; and a solvent. A is a monovalent organic group having 1 to 40 carbon atoms; R1 and R2 are each independently a hydrogen atom, a monovalent fluorine-free organic group having 1 to 20 carbon atoms, a cyano group, a nitro group, a hydroxy group, or an amino group, when there are a plurality of R1s and R2s, the plurality of R1s and R2s are the same or different from each other; m1 is an integer of 1 to 8; and Z+ is a monovalent radiation-sensitive onium cation.