Creating a Bondwire

SIwave analyzes bondwires using a Method of Moments (MoM) field solver. This solver derives a lumped RLC model (wherein mutual inductance is fully captured, but mutual capacitance—which tends to be small for most bondwire structures—is not). The hybrid field solver then uses this model. It is important that bondwires have a homogenous ground plane to ensure optimal levels of accuracy. Also, to ensure the lumped RLC approximation is valid, the bondwires should be electrically "small". Working within these constraints, this approach provides an extremely fast and accurate electrical description of bondwires.

Note:

When the utmost accuracy is required, you may want to consider a full 3D solution in Ansys HFSS. This is especially useful when bondwires have multiple reference planes (non-homogeneous ground) and become electrically large (electrical wavelength should be about 8 times greater than the physical size of the bondwire being solved).

Bondwire models can be assigned to bondwires. Each bondwire has its own bondwire model.

This command is active only when at least one layer has the type WIREBOND. You can edit the layer properties to change the layer type.

Because bondwires are modeled as traces in SIwave, you first need to draw a trace before creating a bondwire. You can also edit the start and end point of the trace from the top-down view.

To define the bondwires:

  1. Click Home > Bondwire Model Editor.

    2. The Bondwire Editor window appears.

  2. Type a model name in the text box. Click the button Create New Model. A new bondwire model is created.
  3. Select the model type from the Model drop-down menu. You can choose from None,JEDEC 4, or JEDEC 5.

    4. The cross-section for the selected model appears below the Model menu.

  4. Enter the parameters for the model, using the cross-section as a guide.
  5. Select the Flip Profile About XY-Plane option if you want to view the bondwire upside-down. This option is not available if the None model type is selected.
  6. Select the Static Diagram option to view a figure defining the model’s parameters. This option is not available if the None model type is selected.
  7. Select the Reverse Pkg & Die option if you want to switch the position of the package and die points. This option is not available if the None model type is selected.
  8. Click OK to create the bondwire.