| InvisaViaTM is a multi-solution process by TTM Technologies.
InvisaViaTM was developed to support the implementation of via in pad technology on high-density PWB designs and
simultaneously eliminate the new assembly issues with solder joint reliability. Our process works with all types of via in
pad technologies. InvisaViaTM can be used on a microvia, blind via, or thru vias. Our multi-solution process gives TTM
the ability to completely fill and planarize over the surface with copper and the surface finish of choice.
Current Industry Problems:
- Wicking: Solder can migrate into a hole away from the BGA causing solder depletion.
- Solder Voids: Applying paste over a hole that is closed on one end, can form an air pocket, which is exacerbated
when the air is heated and expands into the solder joint during assembly.
- Chemistry Entrapment: Chemistry can remain entrapped in the via, migrating onto the pad causing contamination
of solder joints and or corrosion in the hole
- Plating Adhesion: Surface platings to hole fill material have poor adhesion after thermal stress
The bottom line is all these issues have a negative effect on solder joint reliability. For microvias, TTM has developed a
selective dot plating process. This process fills microvia-in-pad with copper while maintaining a nominal thickness on
the balance of solderable surfaces. To support the more traditional blind via or thru via, TTM has developed a
conductive hole fill to completely fill the barrel of the hole. Filling the hole with copper or the conductive fill eliminates
the prospect of chemistry entrapment and solder wicking. Also both our methods of InvisaViaTM will surpass 5X thermal
stress without any degradation of adhesion on the surface plating to the fill material. It has also been shown to reduce
solder voids by up to 74% according to a recent study published in Circuit Assembly magazine. Bottom line, InvisaViaTM
provides an overall improvement in long-term reliability.
Cost:
InvisaViaTM is price competitive with industry standard hole fill plugging materials.
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