Dwight,
Thx.

After BlackBerry ceased making devices and sold off my lab by auction ☹, I went to run the CALCE Lab at the University of Maryland, but for a variety of reasons I was not happy there and resigned after four months and came home to Canada.  The last couple of years I have worked part time as a project facilitator for the High Density Packaging User Group, an electronics industry research consortium of about 50 companies.  So, I personally or through HDP, have not done any CAF testing on what you label ELIC. HDP does have two CAF projects, one looking at developing a new standard coupon that will be offered to the industry and another project looking to develop a new CAF equation.

With regards to stacked microvias, HDP has completed two other projects (presented at SMTAI in 2017), is trying to start a third and is keeping a toe in the pool of the microvia turmoil that the IPC is trying to corral.  Certainly for the materials, construction and suppliers used in those two projects, stacked microvias were not as robust as staggered. 

Regards,
Bev Christian
Project facilitator
HDPUG


-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Dwight Mattix
Sent: September 4, 2019 4:42 PM
To: [log in to unmask]
Subject: [TN] CAF in a uVia world

Nice to see Bev back in the mix so I admit this post is mostly a bit of trolling for his input. :) But I know there are other veterans of the CAF wars so...

For those of you working with full stacked uVia designs (aka ELIC: Every Layer Interstitial Connection) what have you done in terms of CAF testing?

Use one or more of the standard IPC CAF thru via coupons with the hole edge/hole edge spacings down to ~10mils and call it good enough?
Or do you go to custom CAF test vehicle designs that reflect the uVia stack and (tighter) spacing that is typical of uVia designs?