Hi Folks,

Looking for some real world advice.

We're using high pin count BGA's from a manufacturer who recommends a PWB
flatness spec of .25%, The question is this: Is it reasonable to expect a
fabricator to consistently build a 16 layer, .125" thick PWB meeting a .25%
flatness requirement?

The board is 12.25" x 10.25", of balanced construction and has even copper
distribution.

Thanks,
Rick

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