Resist Underlayer Film Material for Planarizing Wide Trenches
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Solution Overview
Problem
In semiconductor device manufacturing, the miniaturization of patterns leads to reduced photoresist film thickness, lower resolution performance, and increased aspect ratios, resulting in pattern collapse and inadequate etching resistance, especially when using monolayer resist compositions. Additionally, there is a need for a resist underlayer film that can effectively planarize and fill complex substrate structures like wide trenches without depending on substrate quality or shape.
Innovation Solution
A resist underlayer film material comprising compounds with specific terminal group structures and an organic solvent, which provides excellent flatness, film-formability, and etching properties, is used in a multilayer resist method. This material includes a combination of aromatic and chain ether groups with terminal triple bonds, and optional additives like acid generators, surfactants, and plasticizers to enhance curing and planarizing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the photoresist film is thinned to accommodate finer patterns, then the aspect ratio is reduced and pattern collapse is avoided, but the etching resistance is lowered and resolution performance deteriorates
Solution Approach 1:
The patent divides the single-layer resist system into multiple functional layers: a lower-layer resist film with high etching resistance and a upper-layer resist film with high resolution. This segmentation allows each layer to specialize in one function, resolving the contradiction between etching resistance and resolution that plagues single-layer systems.
Solution Approach 2:
The patent uses composite material structures by combining different resin types in separate layers. The lower layer uses resins with high etching resistance (like novolak or polyhydroxystyrene), while the upper layer uses resins optimized for resolution (like aromatic polymers). This composite approach allows each material to excel at its designated function without compromise.
2Measurement precision
If resins with low absorbance are used to achieve higher resolution, then the resolution is improved, but the etching resistance is reduced due to faster etching rates
Solution Approach 1:
The patent separates the resolution function and etching resistance function into different layers. The upper-layer resist film contains resins with low absorbance optimized for high resolution, while the lower-layer resist film contains resins with high etching resistance. This functional segmentation resolves the contradiction between resolution and etching resistance.
Solution Approach 2:
Different regions of the resist structure have different material properties tailored to local requirements. The upper layer has low-absorbance materials for optimal light interaction and resolution, while the lower layer has high-etching-resistance materials for protective masking during etching. Each local region's material quality is optimized for its specific function.
3Length of moving object
If the pattern width is reduced without changing photoresist film thickness, then miniaturization is achieved, but resolution performance is lowered and aspect ratio increases causing pattern collapse
Solution Approach 1:
The patent divides the resist system into upper and lower layers with distinct thicknesses and functions. The upper layer can be optimized for fine pattern formation with appropriate thickness, while the lower layer provides additional structural support and etching protection. This segmentation allows miniaturization without compromising resolution or causing collapse.
Solution Approach 2:
The composite resist structure combines materials with different mechanical and optical properties. The upper layer uses materials optimized for light interaction and fine pattern definition, while the lower layer uses materials providing mechanical strength and etching resistance. This composite approach enables miniaturization while maintaining manufacturing precision.
4Reliability
If a multilayer resist method is used to improve etching resistance and resolution, then the manufacturing complexity increases
Solution Approach 1:
The patent segments the resist function into two distinct layers with clear interfaces and defined roles. This segmentation, while adding complexity, provides systematic advantages: the lower layer handles etching protection and the upper layer handles pattern definition. The modular structure makes the complex function manageable and manufacturable.
Solution Approach 2:
The lower-layer resist film serves multiple functions: it provides etching resistance during substrate processing, supports the upper-layer pattern structure, and can be selectively removed after pattern transfer. This multi-functionality justifies the added structural complexity by consolidating multiple roles into a single essential layer.
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 resist underlayer film material effectively forms a flat and uniform film on complex substrates, including wide trench structures, with improved etching resistance and optical characteristics, allowing for precise pattern transfer and reduced substrate dependency, thus addressing the challenges of miniaturization and pattern complexity.
Implementation Method 1
spin-coating a substrate to be processed with the resist underlayer film material
Implementation Method 2
heating the substrate coated with the resist underlayer film material at a temperature of 100° C. or higher to 600° C. or lower for 10 to 600 seconds to form a cured film
Implementation Method 3
a resist underlayer film material in a fine patterning process by a multilayer resist method... which makes it possible to form a resist underlayer film excellent in flatness and film-formability
Implementation Method 4
excellent in flatness and film-formability even on a substrate to be processed having portions that are particularly difficult to planarize such as a wide trench structure
Implementation Method 5
the resist upper layer film pattern can be transferred to the silicon-containing resist middle layer film by dry etching with fluorine-based gas plasma... the pattern is further transferred to the substrate to be processed by dry etching
Data Source
AI summary
A resist underlayer film material contains: one or more compounds shown by the following general formula (1); and an organic solvent. W represents an organic group with a valency of “n” having 2 to 50 carbon atoms; X represents a terminal group structure shown by the following general formula (2) or (3); when a ratio of the structure of the following general formula (2) to that of (3) is “a” to “b”, “a” and “b” satisfy the relations 0.70≤a≤0.99 and 0.01≤b≤0.30. “n” represents an integer of 1 to 10. Z represents an aromatic group with a valency of (k+1) having 6 to 20 carbon atoms. “A” represents a single bond or —O—(CH2)p—. “k” represents an integer of 1 to 5. “p” represents an integer of 1 to 10. L represents a single bond or —(CH2)r—. “1” represents 2 or 3; and “r” represents an integer of 1 to 5.