Vinyl Ether Coating Stabilization for Lithography
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Solution Overview
Problem
Existing coating compositions with vinyl ethers and radiation-sensitive photoacid generators (PAGs) face instability and rapid polymerization due to trace acid contamination, leading to shortened shelf life and incomplete filling of recesses in micro-molding processes, especially in Step and Flash Imprint Lithography.
Innovation Solution
Incorporating stabilizers such as 9-anthracenemethanol or phenothiazine into the coating composition to maintain stable viscosity and prevent premature polymerization, allowing the coating to completely fill recesses without increasing viscosity before exposure to radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vinyl ether materials are used in coating compositions with photoacid generators, then the coating can cure when subjected to radiation, but the viscosity becomes unstable and polymerization occurs prematurely due to trace acid contamination
Solution Approach 1:
A stabilizer compound is introduced as an intermediary substance between the vinyl ether and the photoacid generator. This stabilizer prevents direct interaction between trace acids and the vinyl ether, blocking premature polymerization while allowing the system to remain stable during storage and application.
Solution Approach 2:
The stabilizer provides preliminary protection against acid-catalyzed polymerization before radiation exposure occurs. By preemptively counteracting the harmful effect of trace acids, the stabilizer ensures the coating remains stable throughout storage and processing until intentional curing is initiated.
2Duration of action of stationary object
If the coating composition is stabilized to prevent polymerization, then shelf life is extended, but the ability to completely fill recesses in micro-molding may be compromised
Solution Approach 1:
The stabilizer modifies the chemical environment parameters of the coating composition, specifically preventing acid-catalyzed viscosity increase. This maintains optimal viscosity characteristics over extended periods, ensuring the coating can fully penetrate and fill recesses during micro-molding operations regardless of storage duration.
Solution Approach 2:
The stabilizer performs preliminary protection during storage, preventing any viscosity changes that would occur due to trace acid contamination. This ensures that when the coating is applied for micro-molding, it maintains the appropriate rheological properties needed for complete recess filling, independent of how long it has been stored.
3Stability of the object's composition
If stabilizers are added to maintain viscosity stability, then premature polymerization is prevented, but the device complexity increases
Solution Approach 1:
The stabilizer functions as a consumable protective agent that performs its duty during storage and application, then is consumed or becomes part of the cured network during irradiation. This disposable approach to stabilization avoids the need for complex stabilization systems, as the stabilizer simply needs to function reliably during the critical pre-curing period.
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 stabilized coating composition maintains stable viscosity for extended periods, ensuring complete filling of recesses and extended shelf life, even in the presence of PAGs, and effectively forms a precise relief image upon exposure to radiation.
Implementation Method 1
a stabilizer for stabilizing a viscosity of the stable viscosity coating composition... The stabilizer includes at least one of i) a substituted 9-anthracenemethanol... and ii) a substituted phenothiazine
Implementation Method 2
radiation sensitive photoacid generators (PAGs)... Exposing the coating to radiation through the UV transparent template causes curing of the coating so that the coating becomes a solid
Data Source
AI summary
A stable viscosity coating composition, a method of forming the stable viscosity coating composition and a method for using the stable viscosity coating composition in a micro-molding imprint lithographic process, such as Step and Flash Imprint Lithography is disclosed. The stable viscosity coating composition may include at least one vinyl ether having at least one vinyl ether group (—OCR═CR2), and a stabilizer, wherein the stabilizer may be 9-anthracenemethanol, a substituted 9-anthracenemethanol, phenothiazine, or a substituted phenothiazine. The coating composition may include a radiation sensitive photoacid generator (PAG). The method of forming the coating composition comprises combining at least one vinyl ether having at least one vinyl ether group (—OCR═CR2), and at least one stabilizer.