Resin Composition for Lithography Pattern Formation
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Solution Overview
Problem
Current positive resist compositions for semiconductor microfabrication using KrF excimer laser beams, electron beams, or EUV rays face challenges in achieving wide exposure latitude, low line edge roughness, desirable pattern configuration, excellent dry etching resistance, and minimizing development defects.
Innovation Solution
An actinic ray-sensitive or radiation-sensitive resin composition comprising specific repeating units and a fluorine-containing acid generator, optimized in terms of molecular weight and compositional ratios, which becomes soluble in an alkali developer upon acid exposure, enhancing the balance of lithographic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phenolic acid-decomposable resin is used in positive resist composition, then high sensitivity is achieved through acid catalyzed reaction, but carboxylic acid is generated at exposed area causing extremely high dissolution rate in developer, resulting in pattern upper portions becoming thin and ideal rectangular pattern formation becoming infeasible
Solution Approach 1:
The patent modifies the chemical structure of the resin by introducing specific repeating units (I, II, III) with controlled hydrophobicity and solubility characteristics. The resin contains phenolic groups for acid catalyzed reaction while incorporating hydrophobic groups (aryl groups, cycloalkyl groups) to control dissolution rate, achieving both high sensitivity and proper pattern configuration.
Solution Approach 2:
The patent uses a composite resin structure combining multiple functional groups: phenolic groups for acid catalysis, hydrophobic groups (aryl, cycloalkyl) for controlled solubility, and acid-decomposable acrylate units for pattern formation. This composite structure allows simultaneous achievement of high sensitivity and controlled dissolution behavior.
2Manufacturing precision
If a polymer with extremely high hydrophobicity (e.g., styrene) is used to reduce solubility in alkali developer, then development defects are reduced, but the solubility in alkali developer is excessively lowered increasing the probability of defects
Solution Approach 1:
The patent optimizes the hydrophobicity parameter by selecting specific repeating units with controlled hydrophobic character. The resin contains aryl groups and cycloalkyl groups that provide sufficient hydrophobicity to control dissolution rate without excessive hydrophobicity that would cause complete insolubility. The balance is achieved through the specific combination of units (I), (II), and (III).
Solution Approach 2:
The patent introduces local hydrophobic regions within the polymer chain through specific repeating units while maintaining overall solubility. The aryl groups and cycloalkyl groups are distributed throughout the polymer structure to provide localized hydrophobicity that controls dissolution kinetics without preventing complete dissolution, thus avoiding development defects while maintaining reliability.
3Reliability
If a repeating unit like methyl methacrylate with relatively low hydrophobicity is used, then development defects are less likely, but plasma etching resistance would be unsatisfactory, increasing the difficulty of selective etching
Solution Approach 1:
The patent creates a composite resin structure combining methyl methacrylate units (for low development defects) with aryl groups and cycloalkyl groups (for plasma etching resistance). This composite structure allows the resin to exhibit both low defectivity during development and high resistance during plasma etching processes.
Solution Approach 2:
The patent introduces plasma etching resistant groups (aryl, cycloalkyl) at specific locations within the polymer chain while maintaining overall low hydrophobicity through the presence of methyl methacrylate units. This local distribution of functional groups provides both development friendliness and etching resistance.
4Manufacturing precision
If KrF excimer laser beams are used for lithography, then submicron region ultrafine pattern formation is achieved, but simultaneous satisfaction of wide exposure latitude, decreased line edge roughness, desirable pattern configuration, excellent dry etching resistance and less defects upon development becomes a critical issue
Solution Approach 1:
The patent optimizes multiple parameters of the resin composition simultaneously: molecular weight, repeating unit composition (ratios of units I, II, III), and functional group distribution. These parameter changes enable the resin to satisfy all KrF lithography requirements: wide exposure latitude, low line edge roughness, desirable pattern configuration, excellent dry etching resistance, and minimal development defects.
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 effectively satisfies the requirements of wide exposure latitude, reduced line edge roughness, desirable pattern configuration, and improved dry etching resistance while minimizing development defects, resulting in high-quality pattern formation.
Implementation Method 1
a compound (B) which generates a fluorine-containing acid when irradiated with actinic rays or radiation
Data Source
AI summary
According to one embodiment, an actinic ray-sensitive or radiation-sensitive resin composition includes (A) a resin containing the repeating units of formulae (I), (II) and (III) that when acted on by an acid, becomes soluble in an alkali developer, and (B) a compound that when irradiated with actinic rays or radiation, generates a fluorine-containing acid,wherein each of R1 independently represents a hydrogen atom or an optionally substituted methyl group, R2 represents a halogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group or an optionally substituted aralkyl group, and n is an integer of 0 to 5, provided that when n is 2 or greater, multiple R2s may be identical to or different from each other.