SMOBC
(Solder Mask Over Bare Copper)PCB construction where solder mask is applied directly over copper without a surface finish underneath.
Definition
Solder Mask Over Bare Copper (SMOBC) describes standard PCB construction where solder mask covers the copper traces directly, with surface finish applied only to exposed pads. You may encounter this term in older specifications or IPC documents. All modern PCBs use SMOBC construction. If you see SMOBC in legacy documentation, it simply confirms standard build - no special processing is required.