4 The Probe Station and Other Effects

To try and learn more about the parasitics, we can measure the probe by itself without any connection to the upilex. The results are shown in Fig. 19. The impedance and phase indicate mainly those of a pure capacitance since the magnitude of the impedance goes like $\frac{1}{\omega}$ and the phase is around -90 degrees which is a pure capacitance $\frac{1}{i\omega C}$. The value of the capacitance is about 7 pF.

Figure 19: Impedance and phase of the probe by itself

This can be compared to a measurement with a part that is unbonded from the upilex to the silicon. Unfortunately, we did not have any Layer 1 Backward parts, but we measured a Layer 3 Backward part on the n-side. The p-side had already been bonded. The data for the unbonded part is shown in Fig. 20. It is also almost purely capacitive with a value of about 10 pF.

Figure 20: Impedance and phase of the probe on an unbonded upilex part