Minimizing attenuation of coplanar waveguide on lossy silicon substrates up to 300 GHz

The attenuation constant of coplanar waveguide (CPW), conductor backed CPW (CBCPW) and grounded CPW (GCPW) interconnects is compared up to 300 GHz. Spin-on benzocyclobutene (BCB) dielectric is deposited on low resistivity (10 Ω-cm) silicon (Si) substrates to characterize the loss of interconnects at millimeter-wave (mm-wave) frequencies. CPW fabricated on 58 μm of BCB has similar performance as CBCPW and GCPW fabricated on 8.5 μm and 7.6 μm of BCB, respectively. CPW with thick dielectric layers present attenuation of 1.89 dB/mm at 300 GHz, whereas CBCPW and GCPW have an attenuation of 1.87 dB/mm and 1.96 dB/mm, respectively, at the same frequency.