Aromatic Polymer Resist Underlayer for High-Temperature Etching
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Solution Overview
Problem
Conventional resist under-layers lack thermal stability at high temperatures, etching resistance, and gap-filling properties, which are essential for forming patterns in semiconductor circuits, especially when exposed to KrF or ArF light sources.
Innovation Solution
An under-layer composition comprising an aromatic ring-containing polymer with specific repeating units, a compound with a certain molecular weight, and an organic solvent, which provides superior thermal stability, etching resistance, and gap-filling properties, formed through a spin coating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an organic under-layer is used instead of inorganic under-layer formed by CVD, then the instrument cost is reduced and the process is simplified, but the thermal stability at high temperature (above 400°C) is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the organic under-layer by introducing specific aromatic ring-containing polymers with high thermal stability. The polymer structure includes rigid aromatic rings that maintain structural integrity at high temperatures, allowing the organic under-layer to achieve thermal stability comparable to inorganic materials while retaining the advantages of organic processing.
Solution Approach 2:
The patent creates a composite organic under-layer system by combining aromatic ring-containing polymers with specific additives and solvents. This composite structure provides both the thermal stability required for high-temperature processes and the etching resistance needed for effective pattern transfer, resolving the contradiction between organic processability and thermal performance.
2Manufacturing precision
If the photoresist layer thickness is reduced to prevent collapse, then the resolution is improved, but the etching capability is insufficient
Solution Approach 1:
The patent introduces an organic under-layer as an intermediary between the thin photoresist layer and the substrate. This under-layer serves as a hard mask that provides the necessary etching capability and structural support, allowing the photoresist layer to be made thinner for higher resolution without sacrificing etching performance. The under-layer effectively mediates between the conflicting requirements of thin photoresist and strong etching.
3Reliability
If a dual-layer or triple-layer resist structure is used, then the etching resistance is improved, but the device complexity increases
Solution Approach 1:
The patent makes the organic under-layer multi-functional by designing it to simultaneously provide etching resistance, thermal stability, gap-filling capability, and anti-reflective properties. This universal under-layer structure eliminates the need for separate functional layers, reducing overall device complexity while maintaining or improving etching resistance compared to traditional multi-layer resist structures.
4Ease of manufacture
If the under-layer is formed by spin coating instead of CVD, then the process cost is reduced, but the etching selectivity and etching resistance are compromised
Solution Approach 1:
The patent changes the material composition parameters of the spin-coated organic under-layer to achieve etching resistance comparable to CVD-formed inorganic under-layers. By selecting aromatic ring-containing polymers with appropriate molecular weights and cross-linking characteristics, the organic under-layer achieves sufficient etching resistance for effective pattern transfer while maintaining the cost and process advantages of spin coating.
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 under-layer composition achieves thermal stability above 400°C, prevents voids, and functions as an anti-reflective layer, ensuring effective pattern formation and etching resistance during the semiconductor manufacturing process.
Implementation Method 1
the under-layer composition of resist having superior thermal stability, etching resistance, gap-filling property and void-preventing property
Implementation Method 2
it is necessary to control the light reflection from the under-layer to the overlying resist layer to be less than 1%
Implementation Method 3
the resist under-layer should have a high etching resistance
Implementation Method 4
an organic under-layer, which can be formed by a spin coating process
Data Source
AI summary
An under-layer composition of resist having superior thermal stability, etching resistance, gap-filling property and void-preventing property, and a method for forming pattern using the same are disclosed. The under-layer composition of resist comprises: an aromatic ring containing polymer having the repeating unit of the following Formula 1; a compound of the following Formula 4; and an organic solvent.in Formula 1, R1 is a monocyclic or polycyclic aromatic hydrocarbon group having 5 to 20 carbon atoms, R2 and R3 is independently a monocyclic or polycyclic aromatic hydrocarbon group having 4 to 14 carbon atoms, a is an integer of 1 to 3, and b is an integer of 0 to 2.in Formula 4, n is an integer of 1 to 250.