nRF52840 Lead Finish of the BGA Balls

[John]

We are having a very difficult time soldering the nRF52840 to the PCB. Our Operations Department is asking what the lead finish of the BGA balls is. Would be great to get on the phone with you guys to discuss all the things we have tried. You might have some ideas. Thank you!

[Kaja]

Hi John,

I'm trying to set up a meeting with our package expert, but his in Asia, so we have to find a day where you can join the call in the evening (your time), because we want our production house to join as well. 

But they would like some more information from you:

1) What kind of solder paste are you using ?  SAC305?

2) Can you return failure samples so that we can conduct solderability test to check pad status?

3) Is this your first time using this device?

4) Is this your temperature setting in anyway different from the reflow profile?

5) Could you share pictures of the failing boards?

6) X-rays?

Best regards,
Kaja