Radiation-Sensitive Composition for High Sensitivity and Low CDU
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Solution Overview
Problem
Current radiation-sensitive compositions for lithography face challenges in forming high-sensitivity resist patterns with small Critical Dimension Uniformity (CDU) and reduced development defects, especially for fine line patterns with widths of 40 nm or less.
Innovation Solution
A radiation-sensitive composition comprising a polymer with a hydroxyl group bonded to an aromatic ring and an acid-generating compound containing a radiation-sensitive onium cation and an organic anion, specifically with fluoroalkyl or fluoro groups and an iodo group, to enhance sensitivity and reduce CDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional radiation-sensitive compositions are used for fine line patterns (40 nm or less), then sensitivity is insufficient, but increasing exposure amount degrades resolution and increases CDU
Solution Approach 1:
The patent changes the chemical parameters of the radiation-sensitive composition by introducing specific compounds: a polymer with hydroxyl groups bonded to aromatic rings (providing high dissolution rate enhancement), an acid generator with triarylsulfonium or diaryliodonium cations, and fluorinated compounds (perfluoroisopropyl group and/or fluorophenyl group). These parameter changes optimize the chemical amplification process to achieve high sensitivity while maintaining small CDU for fine line patterns of 40 nm or less.
Solution Approach 2:
The patent creates a composite radiation-sensitive composition combining multiple functional components: the polymer (A) with hydroxyl-aromatic structural units, the acid generator (B) with specific onium cations, and fluorinated compounds (C). This composite material approach synergistically combines high sensitivity, resolution enhancement, and CDU control that cannot be achieved by single components alone.
2Reliability
If exposure amount is increased to improve sensitivity, then pattern formation improves, but development residues increase and rectangularity degrades
Solution Approach 1:
The patent optimizes the chemical parameters of the composition to achieve high dissolution rate contrast between exposed and unexposed regions. The polymer (A) with hydroxyl groups bonded to aromatic rings provides strong acid-catalyzed dissolution enhancement, allowing complete removal of exposed portions with minimal overexposure, thereby reducing development residues while maintaining reliable pattern formation.
3Stability of the object's composition
If conventional acid generators are used, then basic lithographic properties are maintained, but sensitivity and resolution are insufficient for further miniaturization
Solution Approach 1:
The patent changes the acid generator structure from conventional types to specific onium cations (triarylsulfonium or diaryliodonium) combined with fluorinated compounds. This structural parameter change enhances radiation sensitivity and resolution while maintaining lithographic stability through controlled acid generation and diffusion characteristics.
Solution Approach 2:
The patent combines the acid generator (B) with fluorinated compounds (C) having perfluoroisopropyl and/or fluorophenyl groups to create a composite system that provides both high resolution enhancement and stable lithographic performance, overcoming the limitations of conventional single-component acid generators.
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 sensitivity and small CDU, reducing development defects and improving the formation of fine resist patterns with excellent lithographic properties.
Implementation Method 1
irradiating a radiation-sensitive composition with a far-ultraviolet ray such as an ArF excimer laser, an extreme ultraviolet ray (EUV), an electron beam or the like to generate an acid in an exposed portion
Implementation Method 2
causing a difference in a dissolution rate in a developing solution between the exposed portion and the unexposed portion, due to a chemical reaction involving the generated acid
Data Source
AI summary
A radiation-sensitive composition includes: a polymer (A) including a structural unit having a hydroxyl group bonded to an aromatic ring; and an acid-generating compound including a radiation-sensitive onium cation and an organic anion (provided that the polymer (A) is excluded), in which, at least one compound selected from the group consisting of the polymer (A) and the acid-generating compound includes a radiation-sensitive onium cation structure [X] having two or more of at least one substituent β selected from the group consisting of a fluoroalkyl group and a fluoro group (provided that the fluoro group in the fluoroalkyl group is excluded); and an organic anion structure [Y] having an iodo group, in the same compound or different compounds.