Discussion Forum

Hi,

My model started with solid mechanics physics study on the von Mises stress impart onto the underlying bond pad layers by the probe moving downward along the Z-axis with prescribed displacement and auxiliary sweep. Everything is okay there.

As von Mises stress cannot be measured in experiments, I need to obtain the change in resistance of the polysilicon meander structure during the probing process. Therefore, Electric Currents physics from the AC/DC module is applied only to the polysilicon material. The theory behind the model setup is that, as resistance is defined as potential difference divided by current therefore, a potential difference is applied across the polysilicon meander structure (1V at one end and GND at the symmetry plane end) and current is measured at the cross section of the polysilicon where it experienced maximum von Mises stress. The polysilicon is partitioned tangentially across the polysilicon at the maximum von Mises stress point to obtained a boundary for setting up probes (see attached picture). As there is no current boundary probe, the current is further obtained from current density boundary probe and area integration (reduction in area taken into account). Multiplying current density and area gives current. Then, the potential difference of 1V is divided by the current to obtain the resistance...

Is this method of obtaining resistance valid? Is the model setup correctly?? Please advise on anything in the model that were setup incorrectly. I am having problem matching and aligning the simulation results with measured data.

Any help would be greatly appreciated. Thanks in advance.