IC Package - CST2013 MWS Examples

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General Description

This example shows the S-parameter calculation of an arbitrary IC Package. The model consists of a silicon chip which is encapsulated within a nonconductive plastic compound. The surface mounted package is soldered to printed circuit board with a PEC ground layer.

Structure Generation

The package is created by boolean and chamfer operations. The pins are defined by means of extruded profiles and multiple transformations. Loft operations are used to model the traces to the silicon chip inside the package. The entire row of pins is then rotated and mirrored. The silicon chip is modelled as a substrate with a ground layer. Finally the printed circuit board is modelled as a substrate with the electric boundary as the ground layer.

Solver Setup

Before the transient solver can be started, the excitation sources have to be defined. To create the discrete ports in an efficient way, a local VBA macro is used. The macro generates a discrete port between each picked point and the ground plane determined by the z-coordinate of the last picked point. First, ports 1..52 are defined at the pins outside of the package. Then the connections from the metal pin traces to the silicon chip are modelled as bond wires. Ports 101..152 are created with a second macro-call at the ends of the bond wires.

To obtain broadband results for transmission, reflection and crosstalk, port number one is excited with a Gaussian pulse.

Post Processing

Using the excitation of discrete ports the resulting time signals are automatically converted into the corresponding scattering parameters. They are listed in the navigation tree in the folder 1D Results and show the transmission behavior of the device, concerning effects like reflection and crosstalk. Right-click on S-Parameters and use Select Result Curves... to get a better overview.