![Why would metal from a pad be *underneath* the solder mask in a footprint specification? - Electrical Engineering Stack Exchange Why would metal from a pad be *underneath* the solder mask in a footprint specification? - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/KPrFJ.png)
Why would metal from a pad be *underneath* the solder mask in a footprint specification? - Electrical Engineering Stack Exchange
![Copper Defined vs. Solder Mask Defined pad design for BGA soldering strength | I am a Manufacturing Process Engineer (MPE) Copper Defined vs. Solder Mask Defined pad design for BGA soldering strength | I am a Manufacturing Process Engineer (MPE)](https://www.researchmfg.com/wp-content/uploads/images/BGA-pad_EE62/Pull-force-soldermask-defined.png)
Copper Defined vs. Solder Mask Defined pad design for BGA soldering strength | I am a Manufacturing Process Engineer (MPE)
![Copper Defined vs. Solder Mask Defined pad design for BGA soldering strength | I am a Manufacturing Process Engineer (MPE) Copper Defined vs. Solder Mask Defined pad design for BGA soldering strength | I am a Manufacturing Process Engineer (MPE)](https://www.researchmfg.com/wp-content/uploads/images/BGA-pad_EE62/BGA-define-pad.png)
Copper Defined vs. Solder Mask Defined pad design for BGA soldering strength | I am a Manufacturing Process Engineer (MPE)
BGA Land Patterns. BGA Pads. SMD (Solder Mask Defined Pads) and NSMD (Non-Solder Mask Defined Pads) , SMD & NSMD
![With solder mask defined (SMD) pads on the board side, the lower solder fillets are shaped by solder mask covering the periphery of the pads. With nonsolder mask defined (NSMD) pads on With solder mask defined (SMD) pads on the board side, the lower solder fillets are shaped by solder mask covering the periphery of the pads. With nonsolder mask defined (NSMD) pads on](https://www.accessengineeringlibrary.com/binary/mheaeworks/1525861381302a22/6f25900f3c75a34e6cba2a9ee43642f23f402f19104a628931119d7863a3db6e/63x11.png)