Negative Resist Composition With Controlled Acid Diffusion
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Solution Overview
Problem
Existing chemically amplified negative resist compositions face challenges in achieving high etching resistance, organic solvent solubility, and controlled acid diffusion, leading to issues like line edge roughness and dimensional uniformity, especially in the formation of fine patterns using electron beam and extreme ultraviolet lithography.
Innovation Solution
A chemically amplified negative resist composition incorporating a polymer-bound acid generator with specific repeat units derived from an onium salt containing an aromatic sulfonate anion and a phenolic hydroxy group, which controls acid diffusion and enhances etching resistance and solvent solubility, improving lithography performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a chemically amplified negative resist composition uses conventional polymers and crosslinkers, then etching resistance can be improved, but acid diffusion increases causing line edge roughness and poor dimensional uniformity
Solution Approach 1:
The invention divides the resist composition into distinct functional segments: a polymer with specific repeat units (A1) and (A2) that provides controlled acid diffusion, and a separate crosslinking agent that enhances etching resistance. This segmentation allows each component to optimize its function without interfering with the other, resolving the contradiction between etching resistance and dimensional uniformity.
Solution Approach 2:
The invention creates a composite resist system by combining a polymer containing repeat units (A1) with acid diffusion control and repeat units (A2) for etching resistance, together with a crosslinking agent. This composite approach enables simultaneous achievement of controlled acid diffusion (reducing LER) and high etching resistance, which cannot be achieved with single-material systems.
2Strength
If the resist composition enhances etching resistance through crosslinking, then pattern durability improves, but solubility in organic solvents decreases
Solution Approach 1:
The invention performs preliminary solubilization by designing the polymer with repeat units that maintain organic solvent compatibility before the crosslinking step. The crosslinking reaction is then activated only during the etching process, allowing the resist to remain soluble during application and patterning while gaining etching resistance when needed. This preliminary action resolves the contradiction between solubility and etching resistance.
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 achieves high resolution, reduced line edge roughness, and improved pattern fidelity with enhanced etching resistance, making it suitable for fine pattern formation in electron beam and extreme ultraviolet lithography.
Implementation Method 1
an acid generator which is decomposed to generate an acid upon exposure to light
Implementation Method 2
a crosslinker which causes the polymer to crosslink in the presence of the acid serving as a catalyst
Implementation Method 3
Most often a quencher is added for controlling the diffusion of the acid generated upon light exposure
Data Source
AI summary
A chemically amplified negative resist composition contains (A) a base polymer containing a polymer which contains a repeat unit having formula (A1) and a repeat unit having formula (A2). The polymer is adapted to decrease its solubility in an aqueous alkaline solution under an action of an acid. The polymer may serve as a polymer-bound acid generator.