Electronics Forum | Tue Oct 05 12:46:02 EDT 2021 | emeto
From what I understand SAC305 and SAC405 are considered low silver content and have the better overall mechanical qualities compared to more silver or no silver.
Electronics Forum | Mon Aug 24 19:08:28 EDT 2009 | rossi
Thank You for all your help. The PCBs are from the same vendor. You mention the tape test. How exactly do we perform this test? Eric
Electronics Forum | Tue Aug 25 13:30:35 EDT 2009 | rossi
It appears that the crack is between the paste and the ball. We physically pulled off the BGA by force and almost all the balls broke at the PCB. There was a thin layer of solder left on the pad. Maybe 1% of the balls stuck to the pad. I have attac
Electronics Forum | Thu Aug 27 16:03:20 EDT 2009 | jim_n_hky
We recently had a very similar issue with BGA breaking off at the pad. We sent samples to a lab for SEM / EDX and they found that there was no intermatalic with the nickel, or very little do to high phosphorus. I recommend you get a board to a lab AS
Electronics Forum | Mon Aug 31 11:40:23 EDT 2009 | rossi
We have tried 2. The first is 244C and the 2nd is 252C. The processor BGA document recommends a solder temperature above 250C. Eric
Electronics Forum | Fri Aug 21 13:45:12 EDT 2009 | rossi
We are using a vapor phase oven which we have used successfully for a number of years with both leaded and unleaded solders. Recently we experienced problems with a no lead BGA that has low silver balls. The problem is that the soldered boards do no
Electronics Forum | Tue Aug 25 06:11:13 EDT 2009 | ghepo
Eric, use the TM 650 test method annexed. Don't forget to perform many test on many PCB (TOP and BOTTOM)on PADs in several position (at 4 corners and at the center) and obviously in the faulty position. Don't forget to change every time the tape. V
Electronics Forum | Tue Aug 25 07:13:20 EDT 2009 | davef
It sounds like the BGA balls are not melting. You're probably getting no collapse. Put a bare BGA on a hot plate. Heat it up until you get collapse. Adjust your reflow profile until you have that temperature on the BGA pads on the board. What is the
Electronics Forum | Tue Aug 25 10:25:56 EDT 2009 | grahamcooper22
Do you know the exact BGA sphere alloy make-up and the alloys melt temp ? Then you can judge the ideal reflow temperature. Also, does the package warp in the reflow zone ? This may be causing the solder spheres on the BGA to lift off the pcb and henc
Electronics Forum | Mon Aug 24 10:35:54 EDT 2009 | rossi
I don't think its an issue with the PCB. When we just put the paste down and not the BGA the solder paste seems to adhere to the PCB pads very well (not brittle). Also we have other very similar PCBs that we run different normal silver content BGAs
