Organic Underlayer Film Material for Etching Resistance and Planarization
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Solution Overview
Problem
Current organic underlayer films used in semiconductor manufacturing face challenges such as pattern twisting and curvature during dry etching, especially when processing substrates with steps, due to their etching resistance and planarization limitations, and existing materials lack sufficient carbon density and solubility for advanced lithography processes.
Innovation Solution
A polymer with a specific repeating unit structure, including benzene or naphthalene rings and a divalent organic group with aromatic rings, is used to form an organic film that provides high etching resistance, twisting resistance, and excellent filling and planarizing properties, along with an acid generator, surfactant, or plasticizer for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a CVD-C film is used as an underlayer film to improve etching resistance and twisting resistance, then pattern stability is improved, but the ability to fill substrate steps and achieve planarization deteriorates
Solution Approach 1:
The patent changes the material parameters by using a polymer with specific chemical structure (formula 1) containing aromatic rings and divalent organic groups, achieving high carbon density while maintaining solubility. This allows the underlayer film to provide both etching resistance and planarization capability that CVD-C film cannot achieve simultaneously
Solution Approach 2:
The patent creates a composite material system combining the polymer (formula 1) with specific solvents and additives to achieve both the mechanical stability needed for pattern support and the flow characteristics needed for step filling and planarization
2Reliability
If the carbon density of the underlayer film is increased to improve etching resistance, then twisting resistance is improved, but the solubility and film formability deteriorate
Solution Approach 1:
The patent achieves high carbon density through specific molecular structure design (aromatic rings with divalent organic groups) while maintaining solubility by controlling the overall polymer structure and selecting appropriate solvents, resolving the contradiction between carbon density and film formability
Solution Approach 2:
The patent introduces aromatic rings and divalent organic groups at specific positions in the polymer structure to locally increase carbon density and etching resistance, while the overall polymer architecture maintains solubility and processability
3Manufacturing precision
If a spin coating method is used to improve filling of substrate steps, then planarization is improved, but etching resistance and twisting resistance deteriorate due to insufficient carbon density
Solution Approach 1:
The patent changes the fundamental parameter of carbon density by using a polymer with high aromatic content and optimized molecular structure, enabling the spin-coated film to achieve both good filling properties and high etching resistance simultaneously
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 polymer enables precise formation of fine patterns on substrates with complex structures by improving film formability, etching resistance, and planarization, making it suitable for advanced lithography processes and multilayer resist methods.
Implementation Method 1
The carbon hard mask formed immediately above the substrate to be processed is generally an amorphous carbon (hereinafter CVD-C) film prepared by a CVD method
Data Source
Figure 1(A)~1(F)
Figure 2
AI summary
A material for forming an organic film contains a polymer having a repeating unit shown by the following general formula (1), and an organic solvent, where AR1 and AR2 each represent a benzene ring or a naphthalene ring which optionally have a substituent; Wi represents a divalent organic group having 2 to 20 carbon atoms and no aromatic ring, and a methylene group constituting the organic group is optionally substituted with an oxygen atom or a carbonyl group; and W2 represents a divalent organic group having 6 to 80 carbon atoms and at least one or more aromatic rings. This invention provides: an organic film material being excellent in film formability and enabling high etching resistance and excellent twisting resistance and filling property; a patterning process using this material; and a polymer suitable for such an organic film material.