I've always said "if someone's tougher than you, kick in the dipoles and they will bend over then". There is nothing wrong with the material. There are efforts to add an additive/filler that allows the dipoles to move when exposed to energy (force, thermal excursion approaching Tg) and be more flexible (change in modulus). There are many articles on pad cratering and ways to eliminate/minimize its effects. Before you go to that though make sure that's the problem.  The best material in the world still needs to be properly drilled and plated to have a reliable interconnect strategy.
Dewey

-----Original Message-----
From: Robert Kondner [mailto:[log in to unmask]] 
Sent: Wednesday, September 19, 2012 8:21 AM
To: 'TechNet E-Mail Forum'; Whittaker, Dewey (EHCOE)
Subject: RE: [TN] Broken Vias

Dewey,

  Can you elaborate a little on the  " this failure mechanism due to its
inherent toughness"? 

 I did notice literature showing that improper cure (too fast to hot) would
cause the material to contract. I have seen that with epoxies in the past.
Is this material schrikage the cause for the "Cratering" you were referring
to?

 And if this is the case, over cure) what exactly is the nature of the
failure?

Thanks,
Bob K. 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Wednesday, September 19, 2012 9:51 AM
To: [log in to unmask]
Subject: Re: [TN] Broken Vias

Bob,

370HR is an excellent material and will pass the 6 cycles at 160ºC per
IPC-TM-650, Method 2.6.27 with all three types of recommended via protection
strategies, excluding the death slug (CB100). Are you sure the via failures
are not pad cratering? This material with marginal designs is susceptible to
this failure mechanism due to its inherent toughness (sorry for the
dumbed-down technical term, I have been dealing with ISC).

Dewey





-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Tuesday, September 18, 2012 5:38 PM
To: [log in to unmask]
Subject: [TN] Broken Vias



Hi,







This is a follow up on the broken vias on a board with plugged and plated

through vias.







The laminate is 370HR (Tg 180) and the fill material is  PHP-900 IR-6P from

San-Ei Kagaku (Tg 168).







I do not have cross section pictures yet.







If anyone has any ideas on how these material might react to a lead free

reflow process and via barrels would be broken please let me know. I am

interested in any and all ideas.







Bob K.







______________________________________________________________________

This email has been scanned by the Symantec Email Security.cloud service.

For more information please contact helpdesk at x2960 or [log in to unmask]

______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________