Silsesquioxane Hard Mask Adhesion in Nano-Imprint Lithography
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Solution Overview
Problem
In nano-fabrication processes, particularly in imprint lithography, the adhesion between layers in a stack is often low, leading to delamination issues during the template separation step, which affects the integrity and yield of the nano-structured substrates.
Innovation Solution
A polymerizable nano-imprint lithography composition is developed, incorporating a silsesquioxane with a specific formula (R′(4-2z)SiOz)x(HOSiO1.5)y, which forms covalent bonds with non-silicon-containing layers, enhancing adhesion through polar interactions and covalent bonding, and is used as a hard mask layer to improve interfacial adhesion and resistance to tensile forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional polymerizable composition is used to form a hard mask layer, then the etch characteristics are favorable, but the adhesion to non-silicon-containing layers is low causing delamination
Solution Approach 1:
The patent uses a composite polymerizable composition containing both silicon-containing compounds (for etch resistance) and organic compounds with functional groups (for adhesion). This composite approach allows the hard mask layer to simultaneously achieve favorable etch characteristics and strong adhesion to organic layers without delamination during template separation.
Solution Approach 2:
The patent modifies the chemical composition parameters of the hard mask layer by incorporating silicon-containing compounds with specific functional groups (hydroxyl, carboxyl, amine, isocyanate, epoxy, or acrylate groups) that can form covalent bonds with adjacent layers. This parameter change enables the layer to maintain both etch resistance and improved interfacial adhesion.
2Strength
If a pre-treatment process is applied to the hard mask layer to improve adhesion, then the adhesion increases, but the processing complexity and cost increase
Solution Approach 1:
The patent enables the hard mask layer to self-adhere to adjacent layers through the intrinsic bonding capabilities of its functional groups. The silicon-containing compounds with reactive functional groups can directly form covalent bonds with non-silicon-containing layers without requiring external pre-treatment processes, thereby eliminating additional processing steps and reducing complexity.
Solution Approach 2:
The patent incorporates bonding-functionalized silicon-containing compounds into the hard mask layer composition before deposition. This preliminary incorporation of adhesion-promoting functional groups ensures that the layer has inherent bonding capability from the outset, eliminating the need for subsequent pre-treatment steps to enhance adhesion.
3Reliability
If the silicon content in the hard mask layer is increased to improve etch resistance, then the etch characteristics improve, but the adhesion to organic layers deteriorates
Solution Approach 1:
The patent creates a composite hard mask layer composition that balances silicon-containing compounds (providing etch resistance) with organic compounds containing bonding-functionalized groups (providing adhesion). This composite formulation allows the layer to achieve both high etch resistance and strong adhesion to organic layers simultaneously.
Solution Approach 2:
The patent introduces functional groups at specific locations within the silicon-containing compound structure that are dedicated to bonding with adjacent layers. These localized bonding sites (hydroxyl, carboxyl, amine, isocyanate, epoxy, or acrylate groups) ensure strong adhesion to organic layers while the bulk silicon content maintains etch resistance.
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 solution significantly improves the adhesion between silicon-containing and non-silicon-containing layers, reducing delamination and processing costs by eliminating the need for pre-treatment of the hard mask layer, while maintaining favorable etch characteristics and compatibility with organic layers.
Implementation Method 1
forms covalent bonds with non-silicon-containing layers, enhancing adhesion through polar interactions and covalent bonding
Implementation Method 2
enhancing adhesion through polar interactions and covalent bonding
Data Source
AI summary
A nano-imprint lithography stack includes a nano-imprint lithography substrate, a non-silicon-containing layer solidified from a first polymerizable, non-silicon-containing composition, and a silicon-containing layer solidified from a polymerizable silicon-containing composition adhered to a surface of the non-silicon-containing layer. The non-silicon-containing layer is adhered directly or through one or more intervening layers to the nano-imprint lithography substrate. The silicon-containing layer includes a silsesquioxane with a general formula (R′(4-2z)SiOz)x(HOSiO1.5)y, wherein R′ is a hydrocarbon group or two or more different hydrocarbon groups other than methyl, 1<z<2, and x and y are integers. The imprint lithography stack may further include a second non-silicon-containing layer solidified from a second polymerizable, non-silicon-containing composition adhered to a surface of the silicon-containing layer such that the silicon-containing layer is sandwiched between the non-silicon-containing layers.