Aromatic Fused Ring Underlayer for Lithography Pattern Collapse
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Solution Overview
Problem
In semiconductor device production, the miniaturization of resist patterns leads to challenges in obtaining sufficient film thickness and preventing pattern collapse, requiring resist underlayer films with specific dry etching rates and reflection prevention functions, while conventional films struggle with intermixing and high etching rates.
Innovation Solution
A resist underlayer film forming composition containing polymers with specific unit structures, such as aromatic fused rings, oxy rings, and protected carboxyl groups, which form a thin, effective underlayer film that absorbs reflection light and has a controlled dry etching rate, preventing intermixing and enabling precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resist pattern is miniaturized to achieve higher integration, then the resolution is improved, but the film thickness becomes insufficient and pattern collapse occurs
Solution Approach 1:
The patent divides the single resist layer into a multi-layer structure consisting of a resist layer and a resist underlayer film. The resist underlayer film has a thickness of 1 nm to 100 nm and provides mechanical support to prevent pattern collapse, while the resist layer maintains thin profile for high resolution. This segmentation allows the thin resist layer to achieve high resolution without collapsing during processing.
2Object-affected harmful factors
If a conventional reflection preventing film is used, then the reflection prevention function is achieved, but the etching rate is too high causing loss of substance
Solution Approach 1:
The patent changes the chemical composition parameters of the resist underlayer film by incorporating specific polymers with aromatic fused ring structures (naphthalene, anthracene, carbazole units) and controlled glass transition temperatures (50°C to 200°C). These parameter changes result in a material that simultaneously provides reflection prevention and has an etching rate matched to the resist layer, preventing excessive etching and substance loss.
3Productivity
If a resist underlayer film with high etching rate is used, then the processing speed is improved, but the selection ratio becomes unbalanced causing intermixing
Solution Approach 1:
The patent creates a composite material system where the resist underlayer film combines specific polymer components (aromatic fused ring-containing polymers with Tg of 50-200°C) in controlled ratios. This composite structure achieves a balanced etching profile where the etching rate is sufficiently high for efficient processing while maintaining proper selection ratio to prevent intermixing with adjacent layers during etching operations.
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 allows for the formation of precise resist patterns with controlled dry etching rates, preventing pattern collapse and ensuring high accuracy in semiconductor device production, while effectively absorbing reflection light and functioning as a reflection preventing film.
Implementation Method 1
a polymer containing at least one type of unit structure selected from a group consisting of unit structures represented by Formula (1), Formula (2) and Formula (3)... a resist underlayer film forming composition... absorbing reflection light
Data Source
AI summary
There is provided a resist underlayer film forming composition for lithography, which in order to prevent a resist pattern from collapsing after development in accordance with the miniaturization of the resist pattern, is applied to multilayer film process by a thin film resist, has a lower dry etching rate than resists and semiconductor substrates, and has a satisfactory etching resistance relative to a substrate to be processed in the processing of the substrate. A resist underlayer film forming composition used in lithography process by a multiplayer film, comprises a polymer containing a unit structure having an aromatic fused ring, a unit structure having a protected carboxyl group or a unit structure having an oxy ring. A method of forming a pattern by use of the resist underlayer film forming composition. A method of manufacturing a semiconductor device by utilizing the method of forming a pattern.