1、HDI structure：3+N+3 with stacked via,platted for blind hole
2、VIPPO filled by Non-conductive and platted over
3、Vias are cleaned by plasma process
4、Specific impedance controlled with 55+/-5 Ohms 53+/-5 Ohms；
Differential impedance controlled with 90+/-5% Ohms，
100+/-10, Ohms，106Ω±12 Ohms
