Characterization of transmission lines with through-silicon-vias and bump joints on high-resistivity Si interposers for RF three-dimensional modules

摘要

Microstrip lines and coplanar waveguides (CPWs) for RF three-dimensional (3D) modules were characterized on high-resistivity Si interposers: 2,000 Omega.cm. The diameter and thickness of through-silicon-vias (TSVs) in Si interposers were 50 and 250 mu m, respectively. A signal TSV around five ground TSVs, and a signal solder bump around five ground solder bumps were designed to obtain the vertical transitions with low electrical loss between the transmission lines. For the 3D interconnections between Si interposers, a fluxing underfill material was developed and used as a preapplied underfill during the thermocompression bonding. The S-parameters of transmission lines and stacked transmission lines were measured from 0.5 to 10 GHz using a vector network analyzer (VNA) and de-embedded so that their electrical losses were obtained and compared. By comparing with the electrical loss of the transmission line on low-temperature cofired ceramics (LTCC), we found that both transmission lines were sufficiently good for applications in RF 3D modules. (C) 2016 The Japan Society of Applied Physics