Technetters.
We are manufacturing multilayer printed circuit boards.
One of our customers request us to make 6 layer memory module
board(7"X6.3"X0.05"t) of which bow tolerance is Max 0.30%.
It's very tough job.
Our 1st yield for that board is lower than 80%.
Lamination stack height, heating rate, cooling rate, cushion material, layup
construction, coppper balance, baking....
These parameters which I thought related with flatteness were tested many
times. But we still see bowed boards(Max 0.70%).
I will make every effort to make SUPER FLAT BOARD.
Any advice would be appreciated.
Thanks in advance.
Herold Green
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