Resist Underlayer Composition with Methylol Ether Novolac Resin
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Solution Overview
Problem
Existing resist underlayer films in semiconductor production lack improved characteristics such as curability, heat resistance, etching resistance, flattenability, and embeddability, which are essential for advanced microfabrication processes.
Innovation Solution
A resist underlayer film-forming composition comprising a novolac resin with a side chain structure and a solvent, which includes a methylol ether structure, enhancing self-crosslinkability and providing high heat resistance, etching resistance, and excellent applicability on silicon wafers and stepped surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic resins are used for resist underlayer film composition, then the film can be formed, but the curability, heat resistance, etching resistance, flattenability, and embeddability are insufficient
Solution Approach 1:
The patent modifies the chemical structure of novolac resin by introducing a methylol ether group at the para position of the phenolic hydroxyl group. This structural parameter change enables the resin to exhibit both high heat resistance and improved applicability on diverse substrates including silicon wafers and stepped surfaces, while maintaining adequate curability in nitrogen atmospheres
Solution Approach 2:
The invention creates a composite functional structure within the novolac resin molecule by combining the phenolic nucleus with the methylol ether side chain. This composite molecular architecture provides synergistic effects that deliver enhanced heat resistance, etching resistance, and substrate applicability simultaneously
2Reliability
If the resist underlayer film is made to have high etching resistance, then the pattern stability improves, but the embeddability and flattenability may be compromised
Solution Approach 1:
The specific structural modification of adding the methylol ether group at the para position changes the physical and chemical parameters of the novolac resin, resulting in a material that simultaneously achieves high etching resistance and excellent flattenability, allowing the film to conform well to stepped surfaces and silicon wafers
3Device complexity
If conventional novolac resin is used, then the composition is simple, but the self-crosslinkability and curability in nitrogen atmospheres are inadequate
Solution Approach 1:
The patent introduces a methylol ether group with a specific chemical structure (—O—CH2—OH) at the para position of the phenolic hydroxyl group in the novolac resin. This targeted structural modification provides self-crosslinkability and enables curability in nitrogen atmospheres while maintaining relative composition simplicity
Solution Approach 2:
The methylol ether group in the novolac resin provides self-crosslinking capability, allowing the material to cure itself without requiring external crosslinking agents or complex catalytic systems, thus maintaining composition simplicity while achieving adequate curability
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 novolac resin with a methylol ether side chain exhibits adequate curability in nitrogen atmospheres, high heat resistance, and excellent etching resistance, enabling better film formation and processing on diverse semiconductor substrates with improved flattenability and embeddability.
Implementation Method 1
a novolac resin having a methylol ether structure in a side chain... exhibits self-crosslinkability by itself
Implementation Method 2
a resist underlayer film obtained by baking a coating film formed of the composition
Data Source
AI summary
[Problem] The purpose of the present invention is to provide a resist underlayer film-forming composition that can further improve properties of a resist underlayer film, such as curing properties, heat resistance, etching resistance, planarization properties and embedding properties. [Solution] Provided is a resist underlayer film-forming composition characterized by containing a solvent and a novolac resin containing a side chain having a structure represented by formula (D). In formula (D), Ar2 is an aromatic ring. Formula (D): —O—Ar2. The novolac resin contains a conjugated unit structure A-B represented by formula (AB). A unit structure A contains a phenol unit structure and/or an amine unit structure.