60-110 GHz low loss HDI transitions for LCP-packaged silicon substrate

Wideband 3D transitions from 60 to 110 GHz using 50 m via technology on liquid crystal polymer (LCP) are presented. A conductor backed coplanar waveguide (CBCPW) transition on a homogeneous LCP sample shows less than 0.8 dB loss from 60 to 110 GHz. In addition, a CBCPW-to-CBCPW and a CBCPW-to-CPW transition on LCP bonded to silicon substrate are presented also in the range 60-110 GHz. The CBCPW-to-CBCPW transition shows less than 0.5 dB loss up to 100 GHz. The CBCPW-to-CPW transition yields less than 1 dB loss up to 110 GHz. These transitions are the first characterisation of vias in organic substrate packaged silicon in the 60-110 GHz frequency range.