BACK DRILLING METHOD OF THROUGH VIA, CIRCUIT BOARD AND MANUFACTURING METHOD OF CIRCUIT BOARD

摘要

A back-drilling method of through vias in a circuit board and a circuit board made by said method are disclosed. The back-drilling method comprises the steps of: using a drill machine for measuring a localized thickness of the circuit board at a location having a target through via; determining a back drill depth at the location to be back-drilled according to the measured localized thickness and a predetermined percentage; and back-drilling the target through via to the determined depth, thereby forming a back-drilled via extending to a preselected target layer. The circuit board comprises a circuit board body comprising a plurality of spaced conductive layers and a plurality of dielectric layers sandwiched between the conductive layers; and a plurality of through vias drilled through the circuit board body. The through vias are made by said method.