||In this study, Nickel electroforming was integrated with 355 nm wavelength ultraviolet laser process to fabricate the through silicon via packaging. This technology was applied to package the high-frequency solidly mounted resonator (SMR). In the laser drilling experiment, the different parameters of laser power, focus length, termination diameter were set to explore the taper size of via. The silicon sample of 550 μm thickness was drilled under dynamic zoom, laser frequency at 30 kHz, laser power at 90 %, and the termination diameter at 0.05 mm. The drilling diameter of the silicon was about 110 μm where the taper was about 1.63° and the aspect ratio was about 5. |
The relationship of deposition thickness and time was obtained to electroform. The deposition thickness was calculated by current efficiency and current density and the current density was 0.5 Amps per square decimeter (ASD), 1 ASD, 2 ASD, and 4 ASD, separately. Nanoindenter, energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) were used to analyze the material characteristic of electroforming samples. When the current density was lower, Young’s modulus and resistance were lower, and the grain size was lager. The deposition quality was also better than the higher current density. In the end of this study, laser drilling and electroforming were integrated to package the high-frequency SMR. Ground-signal-ground probe was used to obtain the frequency analysis. The S11 parameter was -3.5 dB where the frequency was 2.5 GHz.