Electronics Forum | Fri Jan 17 21:17:18 EST 2003 | Grant Petty
Hi, Our paste release problems have been solved, and we worked on the stencil, and things are working well now. However this board was designed before we knew what was going on, and we thought a little more size on the pads would be a big help. Is
Electronics Forum | Fri Jan 17 09:38:20 EST 2003 | Grant Petty
Hi, We have a BGA that uses .4mm diameter PCB pads on the BGA itself, however we have decided to use .5mm pads on the PCB, to help paste release from the stencil. Is this a bad thing, having different size pads on the PCB compared to the BGA itself
Electronics Forum | Sun Jan 19 10:25:54 EST 2003 | davef
You shouldn't freak. You want the pads on both sides of the BGA ball the same so that the torgue from changes in dimension due to different CTE [ie, interposer, solder, bare board, etc.] is balanced on the top and the bottom of the ball. So, the ma
Electronics Forum | Mon Jan 27 09:43:15 EST 2003 | davef
Sorry. I mistyped information on the guidelines. It should be: SM-785 - Guidelines For Accelerated Reliability Testing Of SM Solder Attachments Order SM-785 from: IPC 2215 Sanders Rd Northbrook, IL 60062-6135 847-509-9700 When you are ordering t
Electronics Forum | Fri Jan 17 15:36:23 EST 2003 | davef
How do 0.5 mm pads on the board help paste release from the stencil? Paste release from the stencil is a function of: * Paste * Printer operation * Stencil design You have no obligation to made your stencil apertures the same size as the pads on yo
Electronics Forum | Wed Jul 01 04:54:28 EDT 2015 | jvercamm
hi, the last post on pad cratering dates from 2012. We have (likely similar) problems with a RoHS 783 solder ball BGA size 29x29mm^2 (organic package BT), pitch is 1mm and solder ball diam is 0.5mm the field failure is after 12 months, almost exclu
Electronics Forum | Thu Jun 29 11:52:23 EDT 2000 | JAX
sree, There is no Definite. You have to make the call. If you think the previous info was on target, use the info provided to find out the appropriate percentage relation between ball diameter, pad diameter, and aperture size. If you already run BGA,
Electronics Forum | Fri May 07 17:02:01 EDT 1999 | Earl Moon
| On 1.27mm (0.050 inches) Standard Ball Grid Array's. | The ball size diameter starts at approximately 0.025 inches. | | If the ball size decreases to 0.012 inches (due to the solder flowing down a via) is the solder connection reliable? | | This
Electronics Forum | Thu May 13 18:36:55 EDT 1999 | Andrew Wulff
| | On 1.27mm (0.050 inches) Standard Ball Grid Array's. | | The ball size diameter starts at approximately 0.025 inches. | | | | If the ball size decreases to 0.012 inches (due to the solder flowing down a via) is the solder connection reliable? |
Electronics Forum | Fri Jun 30 10:42:24 EDT 2000 | Chrys Shea
That pad had a 16 mil dia, so I arrived at 20 mil squares by adding 2 mils to each side of the pad. Following that logic, a 12 mil pad would use a 16 mil square. But a 12 mil pad is on a finer pitch that isn't mentioned, so you should definitely
