Radiation-Sensitive Resin Composition for EUV Lithography
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Solution Overview
Problem
Next-generation photolithography technologies require resist materials with enhanced sensitivity, critical dimension uniformity (CDU) performance, and residual film ratio to maintain pattern quality, which existing materials struggle to achieve, especially with the use of shorter wavelengths like EUV and electron beams.
Innovation Solution
A radiation-sensitive resin composition incorporating specific structural units, an acid diffusion controlling agent, and a solvent, which includes structural units with phenolic hydroxy groups, acid-dissociable groups, and a high acid-dissociation efficiency, along with an acid diffusion controlling agent that absorbs EUV radiation, enhancing sensitivity and pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a shorter wavelength radioactive ray such as EUV or electron beam is used for pattern miniaturization, then resolution is improved, but sensitivity and pattern formation performance deteriorate
Solution Approach 1:
The patent employs a composite resin system combining alicyclic resin units (for radiation resistance and mechanical properties) with aromatic resin units containing acid-dissociable groups (for sensitivity and pattern formation). This composite approach allows the resist to effectively respond to short-wavelength radiation while maintaining adequate sensitivity and pattern formation capability.
Solution Approach 2:
The patent modifies the chemical structure of the resin by introducing specific functional groups (carboxyl, sulfonic acid, phosphonic acid, or carbamic acid groups) that enhance acid-dissociation efficiency. It also adjusts the ratio of alicyclic to aromatic resin units and incorporates iodine-containing compounds to optimize the resist's response to EUV and electron beam radiation, thereby improving sensitivity without sacrificing resolution.
2Reliability
If a resin with enhanced radiation absorption efficiency is used for next-generation lithography, then sensitivity is improved, but critical dimension uniformity and residual film ratio deteriorate
Solution Approach 1:
The patent creates local chemical differences within the resin structure by incorporating aromatic units with acid-dissociable groups in specific proportions (5-50 mol%). These localized functional groups provide high acid-dissociation efficiency and sensitivity in exposed regions, while the alicyclic resin units maintain overall film integrity and critical dimension uniformity in unexposed regions.
Solution Approach 2:
The patent optimizes the chemical composition parameters by controlling the ratio of alicyclic to aromatic resin units and selecting specific acid-dissociable groups. It also adjusts the concentration of iodine-containing compounds (0.1-10 wt%) to achieve the right balance between radiation absorption sensitivity and pattern fidelity, ensuring both high sensitivity and good critical dimension uniformity.
3Manufacturing precision
If a resin with high acid-dissociation efficiency is used to increase solubility contrast, then pattern formation performance is improved, but residual film ratio deteriorates
Solution Approach 1:
The patent carefully controls the type and concentration of acid-dissociable groups (carboxyl, sulfonic acid, phosphonic acid, or carbamic acid) to achieve optimal acid-dissociation efficiency. It also adjusts the overall resin composition and molecular weight to ensure that while exposed regions dissolve efficiently, unexposed regions maintain sufficient film integrity and adhesion, preserving an appropriate residual film ratio.
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 performance, and residual film ratio, enabling high-quality pattern formation even with challenging exposure technologies like EUV, by increasing acid-dissociation efficiency and solubility contrast between exposed and unexposed areas.
Implementation Method 1
Absorption of radiation such as EUV having a wavelength of 13.5 nm by iodine atoms of the acid diffusion controlling agent is very large
Implementation Method 2
an acid generated by irradiating the coating of the resist composition with a radioactive ray through a mask pattern
Implementation Method 3
an acid diffusion controlling agent represented by formula (3)
Implementation Method 4
since the acid diffusion controlling agent has a linking group between the benzene ring and the carboxylate ion thereof, good acid scavenging property can be exhibited
Implementation Method 5
the water repellency of an iodine atom can reduce the solubility of the pattern in the unexposed area in the developer
Data Source
AI summary
A radiation-sensitive resin composition includes a resin, an acid diffusion controlling agent represented by formula (a), and a solvent. The resin includes: at least one structural unit selected from the group consisting of a structural unit represented by formula (1) and a structural unit represented by formula (2); and a structural unit including a phenolic hydroxy group. Rw is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, or an amino group; Lq is a divalent linking group; Z+ is a monovalent radiation-sensitive onium cation; q1 is an integer of 1 to 4; q2 is an integer of 0 to 3; q3 is an integer of 1 to 3; and an upper limit of q1+q2+q3 is 6.