I'm looking for information on long term reliability of inner
layer annular ring break out.    In some cases, tear drop are used in
order to protect against breakout in the trace axis.    However,
tolerance become tighter and tighter and some people already talk about
pad less via.   We plan to launch IST test ( Product life simulated by
thermal shock ) to quantify the possible, if it is the case, lower
reliability of such design.   Does anyone can share its experience on
inner layer break out effect on long term reliability.

Thanks in advance,

Michel [log in to unmask]

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