Harvey-

My understanding of microvias defined:

Vias, usually blind, formed in organic, laminate substrates (PWBs), which
are smaller in diameter than mechanically drilled vias, and thus have
smaller dia pads associated with them.

Microvias are most often formed by laser ablation, photodefined, or plasma
drilled, and some other exotic variants (especially in Japan).

Microvias are often in a buildup layer, and are typically less than 150
microns in diameter, as you've stated.

Make sure you see IPC's great microvia papers page at

http://www.ipc.org/html/hdi.htm

Regards,

Michael Alderete
Aerojet



You wrote...
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Date:    Tue, 6 Apr 1999 10:15:27 +0800
From:    Harvey Monroe PHILLIPS <[log in to unmask]>
Subject: Definition of Microvias

Dear TechNetters,

I have a question about the usage of the term "microvia".  Does it refer
specifically to vias (either blind or through) in a build-up layer or does
it refer primarily to the size of the via (say blind or through vias with
diameters less than 150 microns)?

Thanks,
Harvey Phillips

Research Fellow
Microelectronic Materials and Packaging Group
INSTITUTE OF MATERIALS RESEARCH AND ENGINEERING
TEL:    (+65) 872 7545
FAX:    (+65) 872 7528, (+65) 872 0785
e-mail:  [log in to unmask] <mailto:[log in to unmask]>

Block S7, Level 3
National University of Singapore
Singapore 119260

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