Afternoon Colleagues,

Thanks to those of you who contributed your thoughts on the concept of landless vias.  This is a brief summarization of the responses generated:

Landless holes for component mounting are a solder reliability concern in vibration and some environments.  Landless vias (blind and buried) could be considered acceptable, though etching out of the barrel from the board surface will cause endless problems on multilayer boards.

Landless vias could also be considered acceptable if there are no "external" connections such as traces - otherwise absolutely no breakout should be allowed.

A principal concern would be the preferential attack of the metallization process between the laminate and the hole wall plating, and the subsequent pockets of removal.  


My question is, are there any of us out there that have some reliability data to show landless vs. standard holes?  What are some of the consequences of etching out of the barrel from the board surface on multilayer boards?  


Best,



John Perry
Technical Project Manager
IPC
2215 Sanders Road
Northbrook, Il 60062
1-847-790-5318 (P)
1-847-509-9798 (F)
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