Here is an example for routing a .4 mm pitch device:
Outer Layer With Quadrant Dog bone
DUT Pad .25mm
Via Pad .2mm
Laser Via .125mm
Trace
.1mm, .125mm, .175mm
Outer Layer With Quadrant Dog bone
DUT Pad .25mm
Via Pad .2mm
Laser Via .125mm
Trace
.1mm, .125mm, .175mm
Interesting routing, I might try this one soon. EMS Solutions