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Method for a UV curable thermoset polymer for imprinting applications

IP.com Disclosure Number: IPCOM000010967D
Publication Date: 2003-Feb-05
Document File: 3 page(s) / 30K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an ultraviolet (UV) curable thermoset polymer for imprinting applications. Benefits include improved performance, improved throughput, and an improved manufacturing environment.

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Method for a UV curable thermoset polymer for imprinting applications

Disclosed is a method for an ultraviolet (UV) curable thermoset polymer for imprinting

applications. Benefits include improved performance, improved throughput, and an improved manufacturing environment.

Background

� � � � � Thermoset resins are conventionally used for the imprinting process. If the resin is not advanced sufficiently, it will flow during the subsequent baking (curing) process to the extent that much of the feature definition created during the imprinting process is lost.

� � � � � UV curable and partial UV curable thermoset resins are conventionally used for various applications such as solder masks and dental veneers.

� � � � � UV photoinitiators, such as triphenyl sulfonium hexafluoro antimonate and triphenyl sulfonium hexafluoro phosphate, are used with various liquid epoxy resins, such as epoxidized novolacs, bisphenol-A type liquid epoxy resin and 3,4 epoxy 6 methylclclohexyl 3,4-epoxy-cyclohexane carboxylate. Formulation of these resin systems is known in the industry.

� � � � � The imprinting process for thermoset polymers requires that the polymer be at partial cure B-stage prior to imprinting. Efficiency of the process requires that the actual imprinting step be as short in duration as possible. Keeping the imprinting process short also helps to minimize sticking of the polymer to the imprinting tool. However, after imprinting, the polymer must be fully cured. Typically, an extended bake at an elevated temperature enables the polymer surfaces to be metallized and, later, planarized. During this heating/curing process, the polymer remains for a considerable time in the intermediate viscoelastic state. The polymer typically flows (creeps) due to the viscosity reduction at the elevated temperature prior to and during the polymerization reaction.

        � � � � � Attempted solutions include increasing the imprinting time and temperature to effect additional polymerization of the polymer, which prevents the dramatic reduction in polymer viscosity during the final polymerization processes. This method, however, significantly increases the time required for the polymer to be in the imprinting tool, causing a lack of process efficiency. The opportunity occurs for the polymer to glue the imprinting tools together, making removal of the imprinted piece from the tool set impossible without damaging the imprinted piece or the tool set.

General description

� � � � � The disclosed method is a UV-curable thermoset polymer for imprinting applications. The method dramatically lowers the time required for imprinting a thermoset polymer and prevents flow of the polymer during the final polymer curing process.

Advantages

        � � � � � The disclosed method provides advantages, including:

•        � � � � Improved performance due to improving the loss of imprinted feature distinction because of preventing the imprinted polymer from flowing

•        � � � � Improved throughput due to dramati...