Silicon-Containing Resist Composition for Low-LWR Fine Patterning
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Solution Overview
Problem
The challenge lies in forming silicon-containing resist films with appropriate etching rates and improving line width roughness (LWR) and critical dimension uniformity (CDU) in ultra-fine patterns during multilayer resist methods, particularly in ArF or EUV lithography, where thinning of photoresist films leads to degradation of edge roughness and hole pattern dimension uniformity, and the choice of curing catalysts affects patterning ability.
Innovation Solution
A composition for forming a silicon-containing resist film is developed, comprising polysiloxane with specific repeating units and substructures that undergo elimination reactions upon heat, acid, or base exposure, along with a thermally crosslinkable polysiloxane and a crosslinking catalyst, such as an ammonium or sulfonium salt, to enhance LWR and CDU, and include an acid generator for fine-tuning pattern shape and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist film thickness is reduced to improve resolution for finer patterns, then manufacturing precision is improved, but the aspect ratio increases causing pattern collapse and reliability deteriorates
Solution Approach 1:
The patent employs a multilayer resist system comprising an organic resist upper layer film and a silicon-containing resist middle layer film. This composite structure allows the upper layer to provide high-resolution patterning while the middle layer provides mechanical support and controlled etching resistance, preventing pattern collapse without compromising resolution.
Solution Approach 2:
The resist system is divided into functionally distinct layers: the organic upper layer optimized for optical resolution and the silicon-containing middle layer optimized for etching resistance and mechanical stability. This segmentation allows each layer to be independently optimized for its specific function, resolving the contradiction between thin film requirements for resolution and structural requirements for stability.
2Manufacturing precision
If resins with small optical absorption are selected to improve resolution, then manufacturing precision is improved, but etching resistance deteriorates
Solution Approach 1:
The patent uses a composite resist system where the organic upper layer (novolac or polyhydroxystyrene) provides high resolution with small optical absorption, while the silicon-containing middle layer provides the necessary etching resistance. This resolves the contradiction by distributing these conflicting requirements to different materials within the same system.
Solution Approach 2:
The silicon-containing resist middle layer film acts as an intermediary between the organic upper layer and the substrate. It receives the pattern from the upper layer and transfers it to the substrate with appropriate etching resistance, mediating between the optical requirements of the upper layer and the mechanical/chemical requirements of the substrate processing.
3Productivity
If silicon-containing resist middle layer film etching rate is increased to improve productivity, then productivity is improved, but manufacturing precision deteriorates due to insufficient removal leaving residues
Solution Approach 1:
The patent modifies the chemical composition parameters of the silicon-containing resist middle layer film by incorporating specific polysiloxane structures with silane crosslinking groups. This creates a material with optimized etching characteristics that achieves both high etching rate and complete removal without residues, resolving the contradiction between speed and precision.
Solution Approach 2:
The silicon-containing resist middle layer film has locally optimized properties: it maintains sufficient etching resistance during the pattern transfer process to protect the substrate, but is also designed to be completely removable by fluorine-based plasma or alkaline/fluorine-based etchants without leaving residues. This local quality optimization resolves the contradiction between etching rate and removal completeness.
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 enables the formation of a silicon-containing resist film with high silicon content, improved LWR and CDU, and a favorable etching rate, allowing precise pattern transfer and easy removal of residues, thus enhancing the yield of fine pattern formation on semiconductor devices.
Implementation Method 1
a polysiloxane comprising at least one of any of a repeating unit represented by formula (A-1), a repeating unit represented by formula (A-2), or a substructure represented by formula (A-3): [wherein R1 is a monovalent organic group having 1 to 30 carbon atoms and optionally having a substituent, a halogen atom, a hydroxy group, a sulfo group, a nitro group, or a carboxyl group, functioning as a group eliminated by heat, acid, or base]
Implementation Method 2
a crosslinking catalyst, such as an ammonium or sulfonium salt, to enhance LWR and CDU
Data Source
AI summary
The present invention is a composition for forming a silicon-containing resist film contains a polysiloxane containing at least one of any of a repeating unit represented by formula (A-1), a repeating unit represented by formula (A-2), or a substructure represented by formula (A-3):wherein R1 is a monovalent organic group, a halogen atom, a hydroxy group, a sulfo group, a nitro group, or a carboxyl group, functioning as a group eliminated by heat, acid, or base, and R2 and R3 represent a monovalent organic group. The present invention can provide a composition for forming a silicon-containing resist film such that an ultra-fine resist pattern with excellent LWR (line width roughness) and CDU (critical dimension uniformity) can be formed.