Antireflective Coating Composition for Lithography Pattern Collapse
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Solution Overview
Problem
Negative tone development in photolithographic processes experiences pattern collapse issues due to reflection-related problems, particularly at critical dimensions of 40 nm or less, leading to product quality deterioration and low yields, which is exacerbated by the acidic properties of bottom antireflective coating (BARC) films.
Innovation Solution
An antireflective coating composition comprising a polymer, a photoacid generator with a crosslinkable group, a compound capable of crosslinking the polymer and the photoacid generator, a thermal acid generator, and an organic solvent is used, which reduces PAG loss during spin-coating and enhances acid generation in exposed areas, thereby improving pattern collapse margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional antireflective coating layer is used, then radiation reflection is reduced, but pattern collapse occurs in negative tone development at critical dimensions of 40 nm or less
Solution Approach 1:
The patent changes the chemical composition parameters of the antireflective coating by incorporating specific compounds (e.g., phosphine oxides, sulfones, carboxylic acids) with controlled pKa values and concentrations. This modifies the coating's acidity and chemical reactivity to prevent pattern collapse while maintaining its radiation reflection reduction function.
Solution Approach 2:
The patent creates a composite antireflective coating composition that combines multiple functional components: radiation-absorbing compounds (phosphine oxides, sulfones), acid-generating compounds (photoacid generators, thermal acid generators), and polymer matrices. This composite structure achieves both radiation reflection reduction and pattern collapse prevention through synergistic interactions among components.
2Reliability
If photoacid generator concentration is increased in BARC to improve pattern collapse, then acid generation is enhanced, but PAG dissolves out during spin-coating or reducing resist consumption process
Solution Approach 1:
The patent introduces polymer-solvent interaction mechanisms as intermediaries to protect PAG from dissolving out. The polymer matrix and solvent selection are designed to minimize PAG solubility during spin-coating, while still allowing sufficient acid generation during post-exposure bake. This intermediary protective mechanism maintains PAG concentration without compromising acid generation capability.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously: PAG molecular structure (selecting compounds with appropriate solubility characteristics), polymer matrix composition (controlling solvent interaction), and processing conditions (spin-coating speed, temperature). These parameter changes collectively reduce PAG loss during spin-coating while maintaining effective acid generation.
3Manufacturing precision
If acid generation is enhanced in BARC to improve pattern uniformity, then deprotection reaction is increased, but pattern collapse is exacerbated by acidic BARC surface
Solution Approach 1:
The patent creates spatially differentiated acid generation: photoacid generators are positioned and activated to produce acid primarily in exposed regions where pattern uniformity is needed, while thermal acid generators provide controlled background acid generation. This local quality differentiation enables enhanced deprotection in exposed areas without causing excessive overall acidity that would lead to pattern collapse.
Solution Approach 2:
The patent employs sequential acid generation mechanisms: first photoacid generation during exposure provides localized acid for deprotection in exposed regions, then thermal acid generation during post-exposure bake provides additional controlled acid. This periodic, staged acid generation achieves pattern uniformity while controlling overall acidity to prevent pattern collapse.
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 proposed antireflective coating composition effectively reduces pattern collapse by maintaining PAG concentration and enhancing acid generation, leading to improved pattern uniformity and yield in negative tone development processes.
Implementation Method 1
When such photoresist is exposed to chemical radiation rays, the photoacid generator forms an acid
Implementation Method 2
a thermal acid generator
Implementation Method 3
a compound capable of crosslinking the polymer and the photoacid generator
Data Source
AI summary
An antireflective coating composition, including a polymer, a photoacid generator having a crosslinkable group, a compound capable of crosslinking the polymer and the photoacid generator, a thermal acid generator, and an organic solvent.