Effect of flip-chip package parameters on CDM discharge

CDM peak currents (I
peak
) were studied for the same I/O pin on different dies and flip-chip packages. It is found that I
peak
has strong correlation with linear function of two capacitances: die-to-lid capacitance (C
DUT
, and C
DUT
normalized per die area (C
DUT
/A). The proposed physical model relates CDM current to the two competing discharge paths. The local path is from Si-substrate, where the charge collected from a few millimeters radius. This part of I
peak
is a function of C
DUT
/A. The global path is through a package ground plane, where the charge is collected from Si-substrate via metal routing to the taps. This part of I
peak
is a function of C
DUT
.