Creating PCBs

The Ansys Electronics Desktop uses a tabbed for the creation of a PCB component, including tabs to input General, Geometry, Property, Metal Fraction, and Parameters information. To create components using a wizard interface, access the Icepak>Thermal options in the Options dialog (Tools>Options>General Options) and select Use Wizards for data input when creating new boundaries.

Create a PCB by right-clicking on 3D Components in the Project Manager and selecting Create > PCB. Then set up a link with an existing HFSS 3D Layout design and defining additional Icepak properties.

The PCB Component dialog box General tab contains the following general information for the selected object.

The PCB Component dialog box Geometry tab contains the following settings that define the shape of the PCB:

The Setup Link dialog box General tab contains the following settings that define the source project, design, and solution of the source 3D Layout design:

The Setup Link dialog box Variable Mapping tab contains variable information of the source 3D Layout design:

The Setup Link dialog box Board Settings tab contains the following PCB settings:

The Setup Link dialog box Parts Settings tab can be used to import device parts or package parts:

• Device Parts: Import component devices present on the PCB along with their thermal properties.
  Note: If SIwave per layer outline is enabled, devices on all layers of the stackup of the source design are imported. Otherwise, only devices on the top and bottom layers are imported.
• Package Parts: Import package components like the solderballs and solderbumps defined on the PCB substrate.

To edit layer properties, access the Edit Layers window from the Properties window in the HFSS 3D Layout design. See The Edit Layers Window for more information.

To edit solderbump and solderball properties, use the Component Model window in the HFSS 3D Layout design. See Component Model Window for more information.

In the following example, the solderbumps are modeled as cylinders and the solderballs as boxes.

The PCB Component dialog box Property tab contains the following settings that define the thermal properties of the PCB:

If you select Low side and/or High side, the Low Side and/or High Side tabs contains the following thermal information.

The PCB Component dialog box Metal Fraction contains the following settings for defining the PCB grid resolution and previewing the metal fraction information of each layer of the PCB.

PCB Grid Resolution

The grid resolution that is used to create the thermal conductivity distribution of the board can be customized. Depending on the trace resolution and the computational costs desired, you can change the values for the columns and rows to receive optimum results. The size of the grid is in parentheses next to the column and row count.

The following points outline best practices for balancing accuracy and cost of computing the cell by cell orthotropic thermal conductivity:

• For board-level simulations, enter column and row counts that yield at most a grid size equal to the minimum trace width or minimum via diameter. If possible, use column and row counts that yield a grid size equal to half the minimum trace width or half the minimum via diameter.

• For system-level simulations, enter column and row counts to yield at most a grid size that equals four to eight times the minimum trace width or minimum via diameter.

• For all models, the CFD mesh on the board should equal four to eight times the grid size.

• Column and row counts or CFD meshes that significantly deviate from the above guidelines can adversely affect accuracy.

The PCB Component dialog box Parameters tab contains the following information about the component variables defined for the object.

Creating a PCB

1. In the Project Manager, right-click 3D Components and select Create > PCB.
2. On the PCB Component dialog box General tab, enter following information:
   • Name
   • Company (if known)
   • Model Number (if known)
3. Click the Geometry tab and then click Setup Link.
4. On the Setup Link dialog box General tab, select Edit Link radio button and do the following:
   • Select a Product.
   • Select Use This Project.
     Note:

     Currently, only links between designs within the same project are supported. Use This Project is enabled by default.

   • Select a Source Design.
   • Select a Source Solution.
5. On the Variable Mapping tab, verify the variable settings and edit them if needed.
6. On the Board Settings tab, do the following:
   • Under Extents, enable Use 3D Layout HFSS Extents or select a Type and, if needed, Polygon.
   • Under Thermal Link Specification, select a Frequency.
7. On the Part Settings tab, if importing device or package parts, select Device Parts or Package Parts.
   • Device Parts: If importing electrical and/or mechanical devices, select Include Electrical/Mechanical Parts and, if needed, Simplify all devices as rectangular objects. Under Device Filters, enable the desired filters to be applied during import.
   • Package Parts (Above Stackup): If modeling solderbumps or bondwires, enable Model Connectors As and select Solderbumps or Bondwires. For solderbumps, select the desired type of geometry. For bondwires, select the Bondwire Material and specify the Wire Diameter.
   • Package Parts (Below Stackup): If modeling solderballs, enable Model Solderballs As and select the desired type of geometry.
     Note:

     Only bondwires that are part of a component group in 3D Layout are supported.

1. Click OK to close the Setup Link dialog box.
2. On the PCB Component dialog box Property tab, do the following:
   • Select a Power Dissipated option.
   • If needed, select to specify Low side and/or High side thermal properties.
3. If you selected either Low side or High side, do the following on the Low side and/or High side tabs:
   • Click the button next to Surface Material to open the Select Definition dialog box. On the Materials tab, select the material for the side of the plate and click OK
   • For Radiate To, click All Objects or Reference Temperature. If you selected Reference Temperature, enter a Temperature and View Factor.
4. On the Metal Fraction dialog box, do the following:
   • Use the Minimum Resolution slider bar to set the minimum resolution for the calculation of metal fractions.
     Note:

     You can select Custom and enter the number of columns and rows for a custom grid resolution. See PCB Grid Resolution for more guidance on custom grid resolution.

   • Select a layer from the Show Metal Fraction for Layer drop-down menu and click Display to show a preview image of the selected layer's metal fractions. Repeat this step for the desired layers of the PCB.
5. If you defined any component variables, click the Parameters tab to review the variable(s).
6. If needed, select Map instance parameters to variables and select an option from the drop-down list.
7. Click OK.

Click here for scripting information related to this feature.