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

Abstract

Microstrip lines and coplanar waveguides (CPWs) for RF three-dimensional (3D) modules were characterized on high-resistivity Si interposers: 2,000 Ω·cm. The diameter and thickness of through-silicon-vias (TSVs) in Si interposers were 50 and 250 µm, 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.

TSV Technology and High-Energy Heavy Ions Radiation Impact Review

“…Most of the interposers are made of p-type low-resistivity silicon as the substrate material, and the via holes are filled with Cu. Zhang W. et al [29] discussed different liner and barrier/seed According to the research on the selection of substrate materials, the signal loss of the 10 Hz high-frequency signal passing through the micro-signal line and the CPW (co-planar waveguide) at the silicon interposers made of high-resistance silicon is between 0.062 and 0.072 dB/m, and was studied by Choi K. S. et al [36]. This is of the same order of magnitude as the loss of 0.01-0.02 dB/m when it passes through the LTCC (low-temperature cofired ceramics), indicating that the high-resistance silicon transfer board can be well applied to high-frequency circuits.…”