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.







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