Manufacturing Recommandations

 

 

 

Solder mask expansion should be as small as possible in order to avoid short-circuits between the bga pads and adjacent vias or tracks. 

 

The Solder Mask gerber file should always be reviewed by the assembly house and  negotiated with the pcb manufacturer in order to get ideal parameter suitable for manufacturing especially in the case of 0.4mm BGAs which are close to technology limits. 

 

The best way is the have the assembly house subcontracting the manufacturing of the PCB so as to assure  that all parameters are adapted to their manufacturing processes.