Novolac Resist Underlayer Film Adhesion and Hydrophobicity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In nanoimprinting for semiconductor device production, existing resist compositions face challenges with adhesion to substrates, leading to pattern peel defects and require materials with improved hydrophobicity and controlled optical and etching properties.
Innovation Solution
A resist underlying film-forming composition using a novolac resin with specific repeating unit structures, which provides high hydrophobicity, improved adhesion with hydrophobic upper layers, and adjustable optical constants and etching rates when baked at various temperatures, incorporating a crosslinking agent and acid catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional resist composition is used, then the composition can be applied to the substrate, but the adhesion between the resist composition and the substrate is low, causing pattern peel defects
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the inorganic substrate and the organic resist composition. This coupling agent contains both inorganic-binding groups (for substrate adhesion) and organic-binding groups (for resist adhesion), effectively mediating the interface between dissimilar materials to achieve reliable adhesion and prevent pattern peel defects
Solution Approach 2:
The patent creates a composite adhesion promoter layer combining silane coupling agent, crosslinking agent, and optional resin components. This composite material integrates multiple functions: substrate bonding, resist adhesion, and crosslinked network formation for enhanced mechanical strength and thermal stability at the interface
2Reliability
If a hydrophobic adhesion layer or silicone layer containing Si is formed, then the adhesion between the layer and the resist underlying film is increased, but the film becomes less permeable to hydrophobic gases
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the adhesion promoter layer has varying crosslinking density and composition through its thickness. The region near the substrate has higher crosslinking for adhesion, while the region near the resist underlying film maintains lower crosslinking and higher porosity for gas permeability, thus simultaneously achieving both adhesion and permeability requirements
Solution Approach 2:
The patent incorporates porous structures in the adhesion promoter layer and resist underlying film by controlling the crosslinking degree and adding porogen substances. These controlled pores allow hydrophobic gases to permeate through the film while the crosslinked network maintains adhesion, resolving the contradiction between adhesion strength and gas permeability
3Reliability
If the resist underlying film is made highly hydrophobic to improve adhesion with hydrophobic upper layers, then the contact angle increases, but the planarization property and control over optical constants and etching rate become difficult
Solution Approach 1:
The patent employs parameter changes by systematically varying the silane coupling agent composition, crosslinking agent type and concentration, and baking temperature to achieve the desired balance. By adjusting these parameters, the film's contact angle, planarization property, optical constants, and etching rate are simultaneously optimized to meet multiple requirements
Solution Approach 2:
The patent designs the adhesion promoter layer and resist underlying film to perform multiple functions simultaneously: providing hydrophobic adhesion, ensuring planarization, controlling optical constants for lithography, and regulating etching rate for selective removal. This multi-functional design resolves the contradiction by making the film system universally capable of meeting diverse process requirements
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 composition ensures excellent planarization, high hydrophobicity, and controlled etching rates, reducing pattern defects and enhancing the film's adhesion and permeability to hydrophobic gases, making it suitable for advanced nanoimprinting processes.
Implementation Method 1
when baked at high temperatures
Implementation Method 2
exhibits excellent planarization property, provides a highly hydrophobic film after being baked
Implementation Method 3
The resist composition also fills the inside of the depressed portions of the mold due to capillary phenomena (fill)
Implementation Method 4
incorporating a crosslinking agent and acid catalyst
Implementation Method 5
the resist in this state is cured by heat or a light
Implementation Method 6
the resist composition is cured by irradiation with a light
Data Source
AI summary
A composition for forming resist underlayer film for nanoimprinting includes novolac resin that has a repeating unit structure represented by formula (1). In formula (1), group A represents organic group having an aromatic ring, a condensed aromatic ring, or a condensed aromatic heterocycle, group B represents organic group having an aromatic ring or a condensed aromatic ring, group E represents a single bond or a branched or straight-chain C1-10 alkylene group that may be substituted and may include an ether bond and/or a carbonyl group, group D represents organic group that has 1 to 15 carbon atoms and is represented by formula (2) (in which R1, R2, and R3 each independently represent a fluorine atom, or a straight-chain, branched-chain, or cyclic alkyl group, and any two of R1, R2, and R3 may be bonded to one another to form a ring), and n represents a number from 1 to 5.