Improved Greensheet Punching Performance
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-29
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.