Hi Technet,

Recently we built a new RoHS product with 0.5mm pitch micro BGA, 0.6mm
thickness PCB.  We encountered some yield loss issue with the micro BGA.  We
tried whatever we can but still there's no improvement on yield.

We are thinking this might be a DFM issue because the PCB was built with
Tg130 FR4 material, it's too thin and not rigid enough. The PCB manufacturer
also suggested that change the material to Tg170 would help.  

But while the request of changing to high Tg material came to the designer,
he simply held up and did not agree to make any change.

Are there any IPC standards saying high Tg material is required for RoHS
process?


Thanks 

Willis Tam

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