Aromatic Polymer Resist Underlayer for Etching Selectivity
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Solution Overview
Problem
Conventional resist underlayer materials for microelectronics are difficult to apply and require high-cost methods like chemical and physical vapor deposition, and high-temperature baking, and lack sufficient etching selectivity and optical properties for fine semiconductor device production.
Innovation Solution
An aromatic ring-containing polymer with specific chemical structures is used as a resist underlayer, which can be coated via spin-on techniques, providing excellent optical properties, mechanical characteristics, and etching selectivity, and is resistant to contamination by acid catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional underlayer materials are used, then etching selectivity and optical properties are improved, but application complexity and manufacturing cost increase due to requiring chemical/physical vapor deposition and high-temperature baking
Solution Approach 1:
The patent changes the chemical composition parameters of the underlayer material by incorporating specific aromatic ring-containing polymers with controlled molecular weights and functional group ratios. This compositional parameter change enables the material to achieve high etching selectivity while being compatible with spin-coating application and low-temperature processing, thus resolving the contradiction between reliability and ease of manufacture
Solution Approach 2:
The patent creates a composite underlayer composition by combining aromatic ring-containing polymer main chains with specific side chain functional groups (such as carboxylic acid groups, hydroxyl groups, or ether groups). This composite structure provides both the etching selectivity needed for precise patterning and the processability required for simple spin-coating application without vapor deposition or high-temperature baking
2Reliability
If conventional underlayer materials are used, then etching resistance is improved, but manufacturing cost increases due to requiring special solvents and high-temperature baking
Solution Approach 1:
The patent employs a disposable spin-coating process where the aromatic ring-containing polymer underlayer is applied as a thin film that is subsequently removed after serving its protective function. This approach eliminates the need for expensive special solvents and high-temperature baking processes while maintaining sufficient etching resistance during the critical patterning step, thereby reducing manufacturing cost while preserving etching resistance
Solution Approach 2:
The patent modifies the thermal and chemical parameters of the underlayer material through careful selection of aromatic polymer structures with specific glass transition temperatures and functional group densities. These parameter changes enable the material to provide adequate etching resistance at lower processing temperatures, eliminating the need for expensive high-temperature baking and special solvent systems
3Length of moving object
If the resist layer is made extremely thin to reduce device size, then device miniaturization is achieved, but the resist layer loses sufficient resistance to etching to effectively transfer the desired pattern
Solution Approach 1:
The patent introduces an aromatic ring-containing polymer underlayer as an intermediary protective layer between the thin imaging resist and the underlying material to be etched. This intermediary underlayer provides the necessary etching resistance and mechanical support that would be insufficient in an extremely thin resist layer alone, while allowing the resist to maintain its minimal thickness for device miniaturization. The underlayer acts as a sacrificial support structure that protects during etching and is subsequently removed
Solution Approach 2:
The patent creates a composite structure consisting of the thin imaging resist layer combined with the aromatic ring-containing polymer underlayer. This composite material system combines the high resolution capability of the thin resist with the etching resistance and mechanical strength of the aromatic polymer underlayer, enabling successful pattern transfer even when the imaging resist layer is extremely thin for advanced device miniaturization
Data Source
AI summary
An aromatic ring-containing polymer for a resist underlayer, the polymer including a unit represented by the following Chemical Formula 1:wherein,R1 and R2 are independently hydrogen, a C1 to C10 alkyl group, or an aromatic group,A is a functional group derived from an aromatic compound with a heteroatom or without a heteroatom, andn is an integer of one or more.