Positive Resist Composition Copolymer Surface Energy Contrast
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Solution Overview
Problem
Conventional positive resist compositions used in semiconductor production face challenges in reducing resist pattern top loss and enhancing contrast.
Innovation Solution
A positive resist composition comprising two specific copolymers with a surface free energy difference of 4 mJ/m2 or more, where at least one copolymer includes a halogen atom, preferably fluorine, and specific monomer units, is used to form a resist pattern with reduced top loss and high contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional positive resist composition containing a single copolymer is used, then the resist pattern formation process is simple, but the resist pattern top loss is high and contrast is low
Solution Approach 1:
The patent applies composite materials by combining two different copolymers (copolymer A and copolymer B) with distinct surface free energies into a single resist composition. Copolymer A contains a halogenated vinyl monomer unit and copolymer B contains a different halogenated vinyl monomer unit, creating a composite system that achieves both reduced top loss and high contrast while maintaining manageable complexity through systematic material selection
Solution Approach 2:
The patent implements local quality by assigning different surface free energy characteristics to different copolymer components. Copolymer A and copolymer B are specifically designed with different surface free energies to perform complementary functions: one component optimizes for reduced top loss while the other enhances contrast, allowing each material to contribute its specialized property to the overall resist performance
2Manufacturing precision
If the surface free energy difference between copolymers is small, then the resist composition is easier to formulate, but the resist pattern contrast is insufficient
Solution Approach 1:
The patent applies parameter changes by specifically controlling the surface free energy difference between copolymer A and copolymer B to be within the range of 3-20 mJ/m². This quantitative parameter control ensures optimal contrast while maintaining formulation feasibility. The surface free energy of each copolymer is carefully selected (copolymer A: 20-30 mJ/m², copolymer B: 10-25 mJ/m²) to achieve the desired difference without making the formulation process unduly complex
3Manufacturing precision
If fluorine atoms are included in the copolymer structure, then the resist pattern contrast and reduced top loss are improved, but the synthesis complexity increases
Solution Approach 1:
The patent implements local quality by incorporating fluorine atoms specifically in the side chains of the halogenated vinyl monomer units rather than throughout the entire polymer structure. The fluorine-containing groups are localized in specific positions (R1, R2, or R3 in the general formula) to provide the necessary surface free energy characteristics and contrast enhancement while keeping the main polymer backbone simple and the synthesis process manageable
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 reduces resist pattern top loss and increases contrast by utilizing copolymers with tailored surface free energy and monomer units, improving the formation of resist patterns in semiconductor production.
Implementation Method 1
Polymers that display increased solubility in a developer after undergoing main chain scission through irradiation with ionizing radiation, such as an electron beam, or short-wavelength light, such as ultraviolet light
Implementation Method 2
a difference between surface free energy of the copolymer A and surface free energy of the copolymer B is 4 mJ/m2 or more
Data Source
AI summary
Provided is a technique that enables formation of a resist pattern having little resist pattern top loss and high contrast. A positive resist composition that contains a copolymer A, a copolymer B, and a solvent and in which a difference between surface free energy of the copolymer A and surface free energy of the copolymer B is 4 mJ/m2 or more is used as a positive resist composition.