Hi Steve,



Yes it was. As with any new technology, it took time to learn how to make multilayer boards reliable. Once upon a time wire wrapping was more reliable, and then for a time it was just more well known.



And that\'s a perfect example of just what I was talking about. Once upon a time, plated via barrels were much more prone to breaking. In time people learned that the geometry of the edge corners of the hole concentrates the E-field during plating, causing greater buildup of material at the top and bottom edge than in the middle of the hole. The effect is called \"dog-boning.\" Once people saw what was happening they developed reverse pulse plating, a process wherein the plating is interrupted by pulses of reverse polarity which cause newly plated material to be removed proportionally to the E-field. The net result is that over time you end up with a nicely plated barrel of uniform thickness over the length of the hole, eliminating the weaker middle region. This process is even more important in high aspect ratio vias.

And now that we know how to properly plate a hole, the use of eyelets is the least reliable technique you can use to provide conductivity through vias. In fact, IPC standards explicitly prohibit the use of eyelets or rivets for providing conductivity.