Novolak-Imide Polymer for Semiconductor Resist Underlayer Films
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Solution Overview
Problem
Current semiconductor device manufacturing processes face challenges in forming organic films with excellent solvent resistance, heat resistance, filling property, planarizing property, and pattern formability, particularly in multilayer resist methods where absolute etching selectivity between photoresist films and substrates is lacking, and high integration and complex structures are required.
Innovation Solution
A material comprising a polymer with a specific structure, including an imide group-containing skeleton and a novolak resin, combined with an organic solvent, which provides excellent heat resistance, solvent resistance, and adhesion to substrates, enabling the formation of organic films suitable for high-resolution patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical organic photoresist film is used in a multilayer resist method, then the etching selectivity ratio relative to the silicon-containing resist underlayer film is favorable, but the film thickness is insufficient for directly processing the substrate and the dry-etching resistance is insufficient
Solution Approach 1:
The patent applies composite materials by combining an organic resin component with a silicon-containing resin component in the resist underlayer film. This composite structure provides both the etching selectivity needed for the multilayer resist method and the sufficient dry-etching resistance required for direct substrate processing, eliminating the need for additional thickness compensation.
2Strength
If the film thickness of the resist upper layer film is increased to provide sufficient dry-etching resistance, then the dry-etching resistance is improved, but pattern collapse occurs after exposure and development
Solution Approach 1:
The patent uses a composite resist underlayer film containing both organic resin and silicon-containing resin components. This composite structure provides sufficient dry-etching resistance, allowing the resist upper layer film to maintain optimal thickness for pattern formation without collapse, thus preserving pattern formation margin while achieving the required etching resistance.
3Strength
If a resist upper layer film with sufficient film thickness is used to provide dry-etching resistance, then the dry-etching resistance is improved, but reflection from the substrate at exposure deteriorates the pattern profile
Solution Approach 1:
The patent employs a composite resist underlayer film with organic resin and silicon-containing resin that provides adequate dry-etching resistance. This enables the resist upper layer film to be kept at an optimal thickness that prevents substrate reflection during exposure, thereby maintaining good pattern profile without the need for excessive film thickness.
4Strength
If an inorganic hard mask is used as the silicon-containing resist underlayer film to provide high dry-etching resistance, then the dry-etching resistance is improved, but the temperature required for formation is 300°C or higher which requires high heat resistance
Solution Approach 1:
The patent changes the material composition parameters of the resist underlayer film by incorporating silicon-containing resin components that provide high dry-etching resistance at lower formation temperatures. This allows the film to be formed at temperatures below 300°C while maintaining the required etching resistance, reducing the heat resistance requirements for the organic film.
5Strength
If an inorganic hard mask is used as the silicon-containing resist underlayer film, then the dry-etching resistance is improved, but adhesion to the substrate is compromised due to delamination
Solution Approach 1:
The patent uses a composite resist underlayer film where the organic resin component ensures good adhesion to the substrate while the silicon-containing resin component provides high dry-etching resistance. This composite structure prevents delamination issues associated with inorganic hard masks while maintaining the required etching resistance.
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 material allows for the formation of organic films with enhanced heat resistance, solvent resistance, filling property, and planarizing capability, facilitating high-yield semiconductor device manufacturing by improving pattern formability and reducing defects in multilayer resist processes.
Implementation Method 1
The material allows for the formation of organic films with enhanced heat resistance, solvent resistance, filling property, and planarizing capability
Implementation Method 2
The material comprises a polymer with a specific structure, including an imide group-containing skeleton and a novolak resin, combined with an organic solvent, which provides excellent heat resistance
Implementation Method 3
capable of filling a fine pattern including hole, trench, and fin formed on a substrate to be processed with a film without space, and capable of filling a step- or pattern-dense region and a pattern-free region with a film and planarizing the regions
Data Source
Figure 1(A)~1(F)
Figure 2(G)~2(I)
Figure 3(J)~3(K)
AI summary
A material for forming an organic film is provided, including: a polymer having a structure shown by the following general formula (1A) as a partial structure; and an organic solvent, where in the general formula (1A), W1 represents a tetravalent organic group, W2 represents a single bond or a linking group shown by the following formula (1B), R1 represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, n1 represents an integer of 0 or 1, and n2 and n3 satisfy 0 ≤ n2 ≤ 6, 0 ≤ n3 ≤ 6, and 1 ≤ n2 + n3 ≤ 6, and where R2 and R3 each independently represent hydrogen or an organic group having 1 to 30 carbon atoms, and the organic group R2 and the organic group R3 optionally bond to each other within a molecule to form a cyclic organic group. This provides a material for forming an organic film by which an organic film excellent in solvent resistance, heat resistance, filling property, planarizing property, and pattern formability can be formed.