Chemically Amplified Resist Composition for Chromium Substrates
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Solution Overview
Problem
Chemically amplified resist compositions face challenges in forming stable resist patterns on substrates with chromium compounds due to acid diffusion and pattern stripping or collapse, especially when exposed to high-energy radiation, which affects the resolution and etching resistance of the patterns.
Innovation Solution
A chemically amplified resist composition is developed using a polymer with a high ratio of aromatic ring structure-containing units and sulfonic acid sulfonium salts with fluorinated alkyl chains, which minimizes acid diffusion and pattern stripping by incorporating specific recurring units that enhance adhesion and etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemically amplified resist composition is used for high-resolution patterning, then manufacturing precision is improved, but acid diffusion causes pattern instability and resolution degradation
Solution Approach 1:
A chromium compound film is introduced as an intermediary layer between the resist pattern and the substrate. This intermediate layer acts as a barrier to acid diffusion, preventing the acid generated during exposure from reaching and destabilizing the resist pattern, thereby maintaining both high resolution and pattern stability
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers: the resist composition, a chromium compound film, and the substrate. This composite material approach allows each layer to perform its specific function - the resist provides patterning capability, the chromium compound film provides acid diffusion barrier properties, and the substrate provides mechanical support, collectively resolving the contradiction between resolution and stability
2Manufacturing precision
If EB lithography is used for ultra-fine microfabrication, then manufacturing precision is improved, but image-writing time increases causing throughput decline
Solution Approach 1:
The patent modifies the chemical parameters of the resist composition by incorporating specific compounds that enhance sensitivity to electron beam exposure. This allows achieving the same patterning quality at lower exposure doses or shorter exposure times, thereby maintaining high feature size precision while improving throughput
3Strength
If chromium compound film is deposited on photomask substrate, then etching resistance is improved, but pattern stripping and collapse occur during processing
Solution Approach 1:
The chromium compound film serves as an intermediary layer that provides etching resistance to protect the substrate, while its specific chemical properties prevent direct harmful interactions with the resist pattern that would cause stripping or collapse, thus maintaining both etching resistance and pattern reliability
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 composition effectively forms stable and high-resolution patterns on substrates with chromium compounds, reducing the likelihood of pattern stripping and maintaining etching resistance even after exposure, thereby improving the reliability and performance of microfabrication processes.
Implementation Method 1
a sulfonic acid sulfonium salt having a fluorinated alkyl chain, that is, a side chain capable of acid generation
Implementation Method 2
The major cause of such a change with time is diffusion of an acid generated upon exposure
Implementation Method 3
developing the exposed resist film with an alkaline developer to form a resist pattern
Data Source
AI summary
A chemically amplified resist composition comprises a polymer comprising units having polarity to impart adhesion and acid labile units adapted to turn alkali soluble under the action of acid. The polymer comprises recurring units having formula (1) wherein R1 is H, F, CH3 or CF3, Rf is H, F, CF3 or CF2CF3, A is a divalent hydrocarbon group, R2, R3 and R4 are alkyl, alkenyl, oxoalkyl, aryl, aralkyl or aryloxoalkyl. Recurring units containing an aromatic ring structure are present in an amount ≥ 60 mol% and the recurring units having formula (1) are present in an amount < 5 mol%.