LM317L: mechanical stress LM317LITP (6-Pin DSBGA)

Hey Nico,

Reaching out the packaging team to get an answer for you, please allow 2 business days for an update. 

Thanks,

Vahnroy

Hey Nico,

This is what I recieved from the packaging team

More information on this issue would be required to make a proper assessment, but answering the question:

At the device level, all wafer lots have a solder ball shear test after bump to validate the process.  The min ball shear that a ball should report is 3182 gf/mm2.  

The device also goes through a qualification process where the package is stressed to different conditions.  The details on the qualification can be found at this  link

In order to do a better assessment, answers to the following questions would be helpful:

• What is the stress condition used and referred as “slight mechanical stress”?
• When the solder balls were detached from the package
  • What solder balls were detached from the package ( ll the solder balls, some of them, only corner balls? 
  • What type of failure was observed (cohesive or adhesive)  and what is the interphase of separation?
    • Are there any  images of this (Cross section, and image of the ball and the device post separation?
  • What was the reflow profile used for SMT?
  • Have the guidelines for PCB design  been followed? 
    • A much larger land pad size in the PCB to the recommended  would result in a stress concentration at the die size; 
  • Does the device shows some damage (like die crack, chipping,  ball dents,  etc)  near the area where the ball separated ?

Thanks,

Vahnroy