Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Peter Soland

#16019

Microbridging under 0402 capacitors. | 1 May, 1998

Has anyone experienced profile related microbridging under 0402 capacitors in the past. We use a Sn46Pb46Bi8 paste, 178 degree C L.T.. Double sided board, 2 per panel, 6.5" x 5", convection oven. Profile data; thermalcouples @ components showing 200 degee C, belt speed 80 cm/min, under 6 min total. If we crank up the heat, 215 - 220 degrees C, speed up the belt to 95 cm/min, the microbridging "seems" to go away. My concern is that we are unnecessarily, since we use a low temp relow paste, heat stressing a few of our components for a "band-aid" fix. Thanks, Pete

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Jon Medernach

#16020

Re: Pad Design | 1 May, 1998

A pad design shaped like Home Plate will eliminate the problem, You can get info from Create Group at Panasonic FA They have the patent on this style pad and the most experience working with the 0402 and now have qualified the 0201 Caps from Murata

| Has anyone experienced profile related microbridging | under 0402 capacitors in the past. | We use a Sn46Pb46Bi8 paste, 178 degree C L.T.. Double | sided board, 2 per panel, 6.5" x 5", convection oven. | Profile data; thermalcouples @ components showing 200 | degee C, belt speed 80 cm/min, under 6 min total. | If we crank up the heat, 215 - 220 degrees C, speed up | the belt to 95 cm/min, the microbridging "seems" to go | away. | My concern is that we are unnecessarily, since we use | a low temp relow paste, heat stressing a few of our | components for a "band-aid" fix. | Thanks, | Pete

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