EUV Resist Composition for High Sensitivity and Low Edge Roughness
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Solution Overview
Problem
Current semiconductor lithography processes using EUV light face challenges in achieving high sensitivity, high resolution, and low nano edge roughness simultaneously, leading to deteriorated electrical properties and yield reduction, especially when forming fine patterns with line widths of 32 nm or less.
Innovation Solution
A radiation-sensitive resin composition is developed, comprising specific polymer units that include repeating units with fluorine-containing groups and acid-dissociable groups, which form a chemically-amplified positive-tone resist film sensitive to EUV rays or electron beams, exhibiting improved etching resistance and accurate pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sensitivity of a positive-tone resist used for EUV light is increased, then the wafer processing time is reduced, but the resolution and nano edge roughness deteriorate
Solution Approach 1:
The patent employs a composite polymer system combining polyhydroxystyrene base resin with copolymer units containing both carboxylic acid groups and sulfonic acid groups. This composite structure enables simultaneous achievement of high sensitivity (through sulfonic acid group interaction with photoacid generator), high resolution, and low line edge roughness (through carboxylic acid group contribution to pattern stability). The synergistic effect of multiple functional groups in the copolymer resolves the trade-off between sensitivity and precision.
Solution Approach 2:
The patent systematically varies the compositional parameters of the polymer, specifically controlling the content ratios of different repeating units (polyhydroxystyrene, carboxylic acid-containing, and sulfonic acid-containing units) within defined ranges. By optimizing these compositional parameters, the resist achieves balanced performance in sensitivity, resolution, and line edge roughness, transforming the trade-off relationship into a controllable parameter optimization problem.
2Use of energy by moving object
If the sensitivity of the resist is increased, then the exposure efficiency is improved, but the nano edge roughness increases causing deterioration in electrical properties
Solution Approach 1:
The patent introduces functional groups with different local properties into the polymer structure: carboxylic acid groups provide local stability to reduce edge roughness, while sulfonic acid groups provide local sensitivity enhancement. This spatial distribution of different functional qualities within the same polymer chain allows simultaneous optimization of exposure efficiency and edge quality without compromising either property.
3Productivity
If a polymer compound including an acryloyloxyphenylsulfonium salt is used, then the sensitivity is improved, but the line edge roughness increases
Solution Approach 1:
The patent merges two previously separate functional components into a single copolymer structure: the sensitivity-enhancing sulfonic acid group (from acryloyloxyphenylsulfonium salt) and the edge-stabilizing carboxylic acid group (from hydroxystyrene derivatives). This merging allows both functions to work together in a unified polymer system, achieving high sensitivity while suppressing line edge roughness that would occur with sulfonic acid groups alone.
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 resin composition achieves high sensitivity, low nano edge roughness, and stable formation of accurate fine patterns, enhancing the semiconductor manufacturing process by addressing the trade-off between sensitivity and resolution.
Implementation Method 1
a radiation-sensitive resin composition sensitive to EUV rays or electron beams
Implementation Method 2
a radiation-sensitive resin composition sensitive to EUV rays or electron beams
Implementation Method 3
which form a chemically-amplified positive-tone resist film
Data Source
AI summary
A radiation-sensitive resin composition includes a polymer that includes at least one repeating unit (i) selected from a repeating unit shown by a formula (1), (2), and (3); and a repeating unit (ii) shown by a formula (4).R1 represents a hydrogen atom or a methyl group. Each R2 independently represents one of a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkoxy group having 1 to 12 carbon atoms, and an alicyclic hydrocarbon group having 3 to 25 carbon atoms. p is an integer from 0 to 3, and q is an integer from 1 to 3, and p+q≦5. A chemically-amplified positive-tone resist film that is sensitive to extreme ultraviolet rays (EUV) can be formed using the radiation-sensitive resin composition.