Low-loss and high-isolation through silicon via technology for high performance RF applications

In this study, new TSV structures, TOV (Through Organic Via) and COV (Coaxial Via), are proposed to overcome the lossy problem of the TSV. In the proposed via, a thick insulator, more than 10 μm, can be realized by using the organic lamination process. The lamination process is applied to the silicon hole which is formed by using a deep RIE (Reactive Ion Etching) process. An UV laser was used to drill the laminated organic. To make fully filled metal via, sputtering seeds and copper electroplating methods are used. As results, it was possible to make a 50 μm through-via with a 150 μm depth. The fabricated TOV and COV have very low signal losses compared to standard TSV. Especially, COV has a very good signal isolation due to shield ground wall. The signal loss and isolation of the fabricated COV were 0.044 dB and 43 dB at 10 GHz, respectively.