Silicon Polymer Underlayer Film for Nanoimprint Adhesion
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Solution Overview
Problem
In nanoimprint lithography, there is a lack of suitable underlayer films for improving adhesion and planarity between substrates and resist films, leading to issues like peeling, etching failures, and variations in film thickness, especially on substrates with large aspect ratios and fine patterns.
Innovation Solution
A composition containing a silicon atom-containing polymerizable compound, a polymerization initiator, and a solvent is used to form a resist underlayer film, which is cured through heat-baking or light-irradiation, providing enhanced adhesion, planarity, and etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photoresist is used directly on substrate without underlayer film, then process is simple, but adhesion is poor causing peeling and etching failures
Solution Approach 1:
An underlayer film is introduced as an intermediary between the substrate and the resist film. This underlayer film comprises a specific composition containing polymerizable monomers (acrylate or methacrylate groups), oligomers, and photopolymerization initiators. The underlayer film provides improved adhesion to the substrate while serving as a foundation for the resist film, thereby preventing peeling and etching failures without requiring fundamental changes to the overall lithography process.
Solution Approach 2:
The underlayer film is formed from a composite material system consisting of multiple components: polymerizable monomers (such as glycidyl methacrylate, caprolactone derivatives), oligomers with specific functional groups, and photopolymerization initiators. This composite composition provides synergistic effects that enhance adhesion, planarity, and etching resistance, resolving the contradiction between improved reliability and increased process complexity.
2Reliability
If underlayer film is formed to improve adhesion, then peeling is prevented, but additional process steps are required
Solution Approach 1:
The underlayer film is applied and cured before the resist film is formed, preparing a stable foundation in advance. This preliminary action ensures that when the resist film is subsequently applied and processed, adhesion issues are already resolved, preventing peeling during etching and other processing steps. The underlayer film is cured through photopolymerization using UV irradiation, which is integrated into the existing lithography workflow.
3Manufacturing precision
If substrate has large aspect ratio or fine patterns, then device complexity increases, but conventional resist cannot achieve required planarity
Solution Approach 1:
The underlayer film composition is specifically designed to address local challenges on substrates with complex geometries. The polymerizable monomers and oligomers provide tailored properties that enhance planarity in regions with large aspect ratios or fine patterns. The underlayer film fills in surface irregularities and provides a uniform foundation, enabling the resist film to achieve the required planarity for high-resolution patterning on complex substrates.
4Reliability
If no underlayer film is used, then process is simpler, but etching resistance is insufficient leading to pattern defects
Solution Approach 1:
The underlayer film serves as a protective intermediary between the substrate and the resist film during etching processes. It provides enhanced etching resistance, preventing pattern defects and maintaining feature integrity. The underlayer film's composition, including polymerizable monomers and oligomers, is specifically selected to provide chemical resistance against etching agents while allowing subsequent removal after the resist pattern is transferred.
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 resist underlayer film exhibits improved adhesion to both the resist and substrate, reduces patterning losses, and achieves high resolution and planarity, allowing for successful nanoimprint lithography on substrates with complex geometries.
Implementation Method 1
irradiating the resultant thin film with an active ray such as an ultraviolet ray through a mask pattern
Implementation Method 2
heat-baking the composition while the composition is in a pressurized state to cure the composition
Data Source
AI summary
Disclosed herein is a composition for forming a resist underlayer film used as an underlayer of a resist for nanoimprint in nanoimprint lithography of a pattern forming process by heat-baking, light-irradiation, or a combination thereof to form the resist underlayer film. The composition includes a silicon atom-containing polymerizable compound (A), a polymerization initiator (B), and a solvent (C). The polymerizable compound (A) may contain silicon atoms in a content of 5 to 45% by mass. The polymerizable compound (A) may be a polymerizable compound having at least one cation polymerizable reactive group, a polymerizable compound having at least one radical polymerizable reactive group, or a combination thereof, and the polymerization initiator (B) may be a photopolymerization initiator.