Iodine-Substituted Radiation-Sensitive Composition for Sensitivity and CDU
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Solution Overview
Problem
Existing radiation-sensitive compositions for microfabrication in lithography face challenges in achieving high sensitivity, critical dimension uniformity (CDU), and inhibiting development defects, particularly when exposed to extreme ultraviolet rays and electron beams.
Innovation Solution
A radiation-sensitive composition comprising a polymer with specific structural units, including an acid-labile group and an anionic moiety with an iodine-substituted aromatic ring, combined with a radiation-sensitive onium cationic moiety, enhances sensitivity and CDU while reducing development defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional radiation-sensitive compositions are used, then basic lithography function is achieved, but sensitivity and critical dimension uniformity are insufficient
Solution Approach 1:
The patent employs a composite polymer structure containing both acid-labile groups (for sensitivity and pattern formation) and iodine-substituted aromatic rings (for radiation absorption and acid generation). This composite approach at the molecular level allows simultaneous optimization of sensitivity and CDU by combining functional moieties that individually contribute different properties.
Solution Approach 2:
The patent systematically varies the structural parameters of the polymer, including the type of acid-labile group, the position and number of iodine substitutions on the aromatic ring, and the hydrocarbon group configurations. These parameter changes enable fine-tuning of the composition's response to radiation and its dissolution characteristics, thereby optimizing both sensitivity and critical dimension uniformity.
2Reliability
If radiation-sensitive compositions are optimized for sensitivity, then development defects increase
Solution Approach 1:
The patent converts the potentially harmful effect of excessive acid generation (which causes development defects) into a beneficial outcome by using the iodine-substituted aromatic ring system. The iodine atoms provide controlled acid generation upon radiation exposure, and the specific molecular structure ensures that acid is generated in a controlled manner that enhances sensitivity without causing unwanted side reactions or development defects.
Solution Approach 2:
The patent introduces local functional groups with specific properties into the polymer chain. The acid-labile groups are positioned to respond locally to generated acid, while the iodine-substituted aromatic rings provide localized radiation sensitivity. This local differentiation of functional groups allows the material to exhibit high sensitivity in exposed regions while maintaining stability and avoiding defects in 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 composition exhibits superior sensitivity, critical dimension uniformity, and inhibits development defects, enabling the formation of high-quality resist patterns.
Implementation Method 1
A radiation-sensitive composition for use in microfabrication by lithography generates an acid at light-exposed regions upon an irradiation with a radioactive ray, e.g., an electromagnetic wave such as a far ultraviolet ray such as an ArF excimer laser beam (wavelength of 193 nm), a KrF excimer laser beam (wavelength of 248 nm), etc. or an extreme ultraviolet ray (EUV) (wavelength of 13.5 nm), or a charged particle ray such as an electron beam
Data Source
AI summary
A radiation-sensitive composition includes: a polymer including a first structural unit including a partial structure obtained by substituting a hydrogen atom of a carboxy group or a hydrogen atom of a phenolic hydroxyl group, with an acid-labile group represented by formula (1); and a compound including an anionic moiety and a radiation-sensitive onium cationic moiety. The anionic moiety includes one anion group and an aromatic ring in which at least one hydrogen atom is substituted with an iodine atom. Ar1 represents a group obtained by removing one hydrogen atom from an aromatic ring in which at least one hydrogen atom is substituted with an iodine atom.