Polyaniline Conductive Coating for Low-Roughness Resist Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conductive compositions used in electron-beam lithography for semiconductor devices face issues with surface roughness, film thickness reduction, and migration of acidic substances, leading to poor pattern formation and sensitivity variations, especially when exposed to high temperatures.
Innovation Solution
A conductive composition with a specific conductive polymer and surfactant combination, featuring a water-soluble polymer with a nitrogen-containing functional group and a terminal hydrophobic group, and a basic compound with a conjugated structure, which reduces surface roughness and minimizes the migration of acidic substances to the resist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conductive composition containing a water-soluble conductive polymer and surfactant is used to form a conductive coating film on the resist surface, then the coating performance is improved, but the surface roughness increases and acidic substances migrate to the resist layer causing pattern formation issues
Solution Approach 1:
The patent changes the chemical parameters of the conductive composition by replacing conventional conductive polymers with polyaniline and its derivatives, and adjusting the surfactant structure to have a hydrophobic group at the terminal position. This parameter change reduces surface roughness from conventional levels to Ra≤5nm while minimizing acidic substance migration to the resist layer, thereby improving pattern formation quality while maintaining coating performance.
Solution Approach 2:
The patent creates a composite conductive composition by combining polyaniline (or derivatives) with specifically designed surfactants that have hydrophobic terminal groups. This composite structure allows the surfactant to anchor on the resist surface through its hydrophobic group while the polyaniline provides conductivity, resulting in a stable coating with reduced surface roughness and minimized acid migration.
2Reliability
If the resist surface is coated with a conductive film to prevent charge-up effects during charged particle beam irradiation, then the orbit curvature of charged particle beams is reduced, but film thickness reduction and sensitivity variations occur due to migration of acidic substances
Solution Approach 1:
The patent converts the harmful acidic substances that normally migrate from the conductive coating into a beneficial or neutral state by using polyaniline and its derivatives, which have reduced acidity compared to conventional conductive polymers. The surfactant with hydrophobic terminal groups further anchors the coating to prevent acid migration, thereby maintaining film thickness and sensitivity uniformity while still providing charge-up prevention.
3Productivity
If a highly sensitive chemically amplified resist is used to enhance productivity with charged particle beams, then the sensitivity is improved, but the resist patterns become more susceptible to acidic substance migration causing pattern formation failures
Solution Approach 1:
The patent introduces the surfactant with hydrophobic terminal groups as an intermediary between the resist layer and the conductive coating. This intermediary anchors the coating to the resist surface through its hydrophobic group, creating a stable interface that prevents acidic substances from migrating into the chemically amplified resist, thereby protecting the resist patterns from formation failures while maintaining high sensitivity.
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 solution achieves a conductive coating film with reduced surface roughness and minimal film thickness reduction, enhancing the stability and performance of resist patterns even at elevated temperatures, suitable for next-generation semiconductor processes.
Implementation Method 1
a conductive composition with a specific conductive polymer and surfactant combination, featuring a water-soluble polymer with a nitrogen-containing functional group and a terminal hydrophobic group
Implementation Method 2
a basic compound with a conjugated structure, which reduces surface roughness and minimizes the migration of acidic substances to the resist layer
Data Source
AI summary
A conductive composition which contains a conductive polymer (A) comprising a polyaniline and a basic compound (E2), which is a quaternary ammonium salt in which at least one of four groups bonded to a nitrogen atom is an alkyl group having 3 or more carbon atoms, is provided. A conductive composition, containing a polyaniline comprising a monomer unit having an acidic group; and a basic compound (E3) having a basic group and two or more hydroxyl groups in the molecule, and having a melting point of 30° C. or more, is also provided.