Mechanically drilled microvias

Microvias that are created by laser drilhng can be located at a reduced pitch for CAF studies because one does not expect drill damage from a laser-ablated hole and it will not be subjected to the drill wander of a mechanically drilled hole. Thus, laser drill tolerances are below 0.025 mm (0.001 in.). 

FIGURE 6Z8 Microvia capabilities shown by base thickness and hole diameter. Also shown is the range of technologies from HDI to mechanical drilling required to create the vias. 

Nonphotoimageable, Nonreinforced Dielectric Materials. This group can be laser-drilled, plasma-etched, and/or mechanically treated to form microvias. As stated earlier, many of the photoimageable dielectrics are laser-drillable. 

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