8-layer HDI PCBs with immersion gold

8 layers
HDI with 1+N+1 structure
FR4(Tg150) material 
1.60mm thick
H OZ base copper on all layers
ENIG surface finish
Matte green solder mask
With hard gold fingers at the edge-board
3.2/4.0mil min w/s(line width/spacing)
Min drill bit 0.20mm  
BGA pad size: 0.25mm
With blind holes from L1 to L2 from L7 to L8
With buried holes from L2 to L7