Do you know the difference between SMD (Solder Mask Defined) and NSMD (Non-Solder Mask Defined) pad designs for PCB? What are the advantages and disadvantages of each? More importantly, which pad design provides better resistance to BGA solder joint cracking under mechanical stress?
A few years ago, our company went through a management change. It’s a familiar story in many companies—new managers often like to introduce new ideas to make their presence felt. One of the first changes was a new PCB design rule: all future BGA layouts should use NSMD pads instead of SMD pads. The idea was that NSMD pads would create stronger solder joints, making BGAs more resistant to mechanical stress and increasing the likelihood of passing impact drop tests and tumble tests.
