Radiation-Sensitive Resist Composition for EUV Acid Diffusion Control
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Solution Overview
Problem
Existing photolithography techniques face challenges in achieving high sensitivity, critical dimension uniformity (CDU) performance, and line width roughness (LWR) performance, particularly with the use of next-generation radiation sources like EUV, due to limitations in resist material performance.
Innovation Solution
A radiation-sensitive composition incorporating a polymer with an iodo group-containing aromatic ring structure, a radiation-sensitive acid generator, and an acid diffusion controlling agent, which enhances radiation absorption, photoelectron generation, and controls acid diffusion, thereby improving sensitivity, CDU, and LWR performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photolithography resist materials are used with next-generation radiation sources (EUV), then the existing photolithography process can be maintained, but sensitivity, CDU performance, and LWR performance are insufficient
Solution Approach 1:
The patent employs a composite resist material system comprising a polymer base material, a radiation-sensitive acid generator containing an onium salt and organic acid anion, and an acid diffusion controlling agent. This composite structure enables the material to simultaneously achieve high sensitivity to EUV radiation, improved critical dimension uniformity, and reduced line width roughness by combining the advantages of each component in a synergistic manner
Solution Approach 2:
The patent modifies key parameters of the resist material system by introducing specific functional groups (iodo group, hydroxy group, sulfo group, sulfanyl group) and controlling the pKa values of acids involved. These parameter changes optimize the material's response to radiation while controlling acid diffusion characteristics, thereby improving manufacturing precision metrics
2Use of energy by moving object
If the polymer structure is modified to improve radiation absorption, then sensitivity increases, but acid diffusion control becomes more difficult
Solution Approach 1:
The patent introduces an acid diffusion controlling agent as an intermediary substance that mediates between the acid generator and the polymer matrix. This agent controls the diffusion rate of generated acids, allowing the system to benefit from high radiation absorption while maintaining precise control over acid distribution and reaction zones
Solution Approach 2:
The patent creates local quality differences within the resist film by controlling acid diffusion to specific regions. The acid diffusion controlling agent ensures that acids are distributed locally where needed, maintaining high radiation absorption efficiency while preventing uncontrolled diffusion that would degrade pattern quality
3Reliability
If the acid generator system is enhanced to improve photoelectron generation, then sensitivity improves, but the complexity of the composition increases
Solution Approach 1:
The patent designs the acid generator system with multi-functionality, where the onium salt and organic acid anion combination serves multiple purposes: generating photoelectrons upon radiation absorption, providing acid catalysis for polymer dissolution, and controlling diffusion characteristics. This universal design improves sensitivity without proportionally increasing complexity
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 superior sensitivity, CDU, and LWR performance, enabling the formation of high-quality resist patterns suitable for next-generation photolithography technologies.
Implementation Method 1
a radiation-sensitive acid generator including a first organic acid anion and a first onium cation
Implementation Method 2
At least one selected from the group consisting of the polymer, the radiation-sensitive acid generator, and the acid diffusion controlling agent includes an iodo group
Implementation Method 3
an acid diffusion controlling agent which includes a second organic acid anion and a second onium cation and capable of generating an acid having a pKa higher than a pKa of an acid to be generated from the radiation-sensitive acid generator by irradiation with radiation
Data Source
AI summary
A radiation-sensitive composition includes: a polymer including a structural unit which includes an acid-dissociable group; a radiation-sensitive acid generator including a first organic acid anion and a first onium cation; an acid diffusion controlling agent which includes a second organic acid anion and a second onium cation and capable of generating an acid having a pKa higher than a pKa of an acid to be generated from the radiation-sensitive acid generator by irradiation with radiation; and a solvent. The first organic acid anion includes an acid anion moiety and an aromatic ring including a first substituent and a second substituent. The first substituent and the second substituent are each independently a hydroxy group, a sulfo group, or a sulfanyl group. At least one selected from the group consisting of the polymer, the radiation-sensitive acid generator, and the acid diffusion controlling agent includes an iodo group.