SST-NIL Curable Composition for Fast Imprint Filling
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Solution Overview
Problem
The photo-nanoimprint technology faces challenges with long filling times, leading to low throughput due to the breakage or clogging of mold patterns, which significantly reduces the yield of the imprint process.
Innovation Solution
A method involving a short spread time nanoimprint lithography (SST-NIL) process, where a curable composition with a higher surface tension and specific particle concentration is used to form a mixture layer that quickly spreads and fills the mold pattern, reducing filling time and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photo-nanoimprint technology is used with standard curable composition, then the mold pattern can be transferred, but the filling time is long leading to low throughput
Solution Approach 1:
The patent changes the surface tension parameter of the curable composition by selecting specific compounds (acrylate or methacrylate esters with particular molecular structures) to achieve higher surface tension. This parameter change enables faster spreading and filling of the composition into the mold pattern, reducing filling time from conventional levels to 10 seconds or less, thereby improving throughput while maintaining pattern transfer quality
Solution Approach 2:
The patent applies a pretreatment coating to the mold surface before applying the curable composition. This preliminary action modifies the mold surface properties to enhance wetting and spreading of the composition, ensuring rapid and uniform filling of the pattern features. The pretreatment coating is applied in advance and cured to create an optimized surface for subsequent composition application, thereby reducing the filling time required
2Reliability
If conventional photo-nanoimprint technology is used, then the imprint process can proceed, but mold pattern breakage or clogging occurs reducing yield
Solution Approach 1:
The patent carefully controls the particle concentration parameter in the curable composition, limiting particles with diameter of 0.07 μm or more to less than 2,021 particles/mL. This parameter control prevents particle accumulation and clogging in the fine mold patterns, eliminating the harmful effect of pattern breakage or clogging while maintaining sufficient composition viscosity for proper filling
Solution Approach 2:
The patent employs a disposable pretreatment coating layer on the mold surface that is replaced or refreshed between production runs. This disposable coating prevents cumulative contamination and pattern degradation that would occur with repeated use of the same mold surface, thereby maintaining high yield by preventing mold pattern breakage or clogging over multiple imaging cycles
3Productivity
If curable composition with higher surface tension is used to reduce filling time, then throughput improves, but the composition may not properly wet the mold surface
Solution Approach 1:
The patent introduces a pretreatment coating as an intermediary layer between the mold surface and the high surface tension curable composition. This intermediary coating has surface properties that are compatible with both the mold substrate and the curable composition, facilitating proper wetting and adhesion. The pretreatment coating acts as a mediator that enables the high surface tension composition to spread rapidly while still maintaining intimate contact with the mold pattern features, ensuring both fast filling and high pattern transfer quality
Solution Approach 2:
The patent uses a composite system consisting of the pretreatment coating combined with the curable composition containing specific acrylate or methacrylate esters. This composite approach combines the surface-modifying properties of the pretreatment coating with the controlled surface tension and particle characteristics of the curable composition, achieving both rapid wetting/spreading and precise pattern transfer that neither component could achieve alone
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 SST-NIL process enhances the yield and throughput of the imprint process by shortening the filling time and minimizing mold pattern breakage or clogging, resulting in improved pattern transfer efficiency.
Implementation Method 1
the resist 102 is filled into a groove portion on the mold 105 as indicated by the arrows 104 showing the direction in which droplets spread by the capillary phenomenon
Implementation Method 2
a component (B) serving as a photopolymerization initiator... when the curable composition is irradiated with light, the photopolymerization initiator generates radicals
Data Source
AI summary
Provided is a method of producing a cured product pattern, including: a first step (arranging step) of arranging a layer formed of a curable composition (α1′) that is the components of the curable composition (α1) except the component (D) serving as a solvent on a substrate; and a second step (applying step) of applying droplets of a curable composition (α2) discretely onto the layer formed of the curable composition (α1), the curable composition (α1) having a number concentration of particles each having a particle diameter of 0.07 μm or more of less than 2,021 particles/mL, and the curable composition (α1′) having a surface tension larger than that of the curable composition (α2).