Rigid-flex-0.2 BGA

8 layers
Rigid-flex board
FR4 (Tg170) material
0.35mm thick in the rigid area
0.13mm thick in the flex area
1 OZ finished copper on all layers
ENIG surface finish
Green solder mask
Min. w/s(line width/spacing)5.0/5.0mil
BGA pad size is only 0.35mm
Min drill bit 0.20mm
Flex area is from L4 to L5,
With blind holes between L1 and L3, between L7 and L8