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Browse Prior Art Database

Improved Greensheet Punching Performance

IP.com Disclosure Number: IPCOM000037610D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Casey, JA: AUTHOR [+2]

Abstract

When punching via holes in a greensheet, microvoids in the vicinity of the punched via are created when the polymer/filler particle interface is so weak that the polymer tears away from the particle surface. The voids result in an increase in volume of the sheet characterized by deformation commonly referred to as embossing. Poor adhesion of the organic binders to the surface of the filler particles causes this poor sheet performance. In the case of good binder-to-binder adhesion, the fracture occurs within the polymer phase, giving superior via location accuracy.

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Improved Greensheet Punching Performance

When punching via holes in a greensheet, microvoids in the vicinity of the punched via are created when the polymer/filler particle interface is so weak that the polymer tears away from the particle surface. The voids result in an increase in volume of the sheet characterized by deformation commonly referred to as embossing. Poor adhesion of the organic binders to the surface of the filler particles causes this poor sheet performance. In the case of good binder-to- binder adhesion, the fracture occurs within the polymer phase, giving superior via location accuracy.

Good binder-to-filler adhesion is achieved through the use of materials chosen for compatible acid: (or electron acceptor: donor) characteristics. An acidic binder material, such as polyvinylbutyral, adheres well to a basic ceramic, such as alumina; whereas the same binder will not adhere well to an acidic glass, such as silica. If the choice of binder systems is limited, for example, to acidic polyvinylbutyral, one can effect a surface modification whereby the acidic silica is treated to coat the surface of the silica particles with a basic inorganic, such as Al2O3 . The particles then appear basic to the acidic polyvinylbutyral, and the adhesion will be improved. Similarly, a basic Al2O3 could be silica-coated for use with a more basic binder system, such as polymethyl methacrylate. Other surface modification techniques, such as treating the acidic filler with...