Shift-aligned GSG transitions through a silicon wafer

Transitions composed of three via-holes, which are aligned in triangular shape, is proposed. The transition realized a high-frequency signal path from the surface of a thick silicon wafer to the other side. To reduce the reflection loss, the signal via is disposed shifted. The transition is fabricated with our developing molten solder ejection method, which ejects small droplets of solder like an ink-jet-printer. Without utilizing thick metallizing process inside the holes, high aspect ratio structure was achieved. The height of the holes is 250μm in this study with diameter of 100μm. The measured results showed the shift-aligned GSG transition had 0.4dB loss at 40GHz.