As you can see from the above discussion, the Import Template makes it convenient to import the same types of structures easily. Also, the Adv Edit->Build Holes and Vias from Selected Polygons command is very powerful in building vias and other structures requiring Boolean operations.
Upon the request from customers, we have implemented the automatic vias in the Import Parameters dialog and even the Import Template file. You can configure the MGRID to create automated vias upon importing. We will discuss this feature in modeling multi-layer structures in this section.
Step 1 Run MGRID. Please select File->Import command. MGRID prompts you for the Import Options dialog. Select “GDSII” for the format. Select OK to continue. MGRID will prompt you for the GDSII file to be imported. Select the file: c:\ie3d\samples\vias_on_layers.gds file. MGRID will read the file and detect all the structures in the file. Then, it will prompt you the Import Data Option dialog (see Figure 6.29). As you can see, all the layers are defined with some assumed Z-coordinates by default. If you select the Basic Parameters button, you will see the substrates and metallic types are also defined with the default values.
Step 2 Select the Load button in the Template File section. Select the file:
.\ie3d\samples\vias_on_layers.ctp file. The template file is read and the data inside the file is used to define the layers (see Figure 6.30). If you chose the Basic Parameters dialog, you will see that the substrate parameters are also re-defined. All the information is from the vias_on_layers.ctp template file. This file is saved by selecting the Save button on the Template File section after we defined all the layers and substrate in a previous importing process. The layers are documented in Table 6.6. The configuration is shown in Figure 6.31. Basically, the layers and the polygons on the layers define a microstrip to strip line transition with finite ground plane in a PCB. The polygon on the No.5 layer defines the shape of the hole on the No.3 layer or the top ground plane. The polygon on the No.6 layer defines the shape of the via connecting the two traces on the No.2 and No.4 layer and going through the hole on the No.3 layer. The polygons on the No.7 layer define the shapes of the vias connecting the 2 ground plane layers or the No.1 and No.3 layers.
6-23 Figure 6.29 The Import Data Options dialog before opening the: vias_on_layers.ctp file.
Table 6.6 The layers and their descriptions
No. Z (mils) No. of Polygons Description
0 -39.3701 0 This layer is not used.
1 0 1 This layer is the bottom finite ground of the stripline configuration.
2 20 2 This is the stripline trace layer.
3 40 1 This layer is for the top finite ground of the stripline or the finite ground of the microstrip configuration.
4 60 2 This is the microstrip trace layer.
5 80 1 This layer defines the shape of the hole on the top finite ground. The hole is for the via connection between the traces 6 100 1 This layer defines the shape of the via connecting the 2
traces.
7 120 1 This layer defines the shape of the vias between the 2 ground planes.
Step 3 Select OK to continue. The polygons are imported and the layers are put into the right Z-coordinates and the Basic Parameters are setup correctly. Please save the file as:
.\ie3d\practice\vias_on_layers.geo. Based upon the description in Table 6.6, we are able to use the polygons on different layers to create the holes and vias for the final structure. However, this process can be automated using the Template File. We are going to demonstrate it.
Step 4 Repeat the Steps 1 and 2. We get all the layers defined in the: vias_on_layers.ctp file, and the Import Parameters dialog is shown in Figure 6.30.
Step 5 Click at the No.5 Symbol=L005, MetalType = 1, Objects = 1 layer in the Layer Definition list box to highlight it (no double-clicking it). Then, please hit the Insert button (see Figure 6.32).
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The Edit Polygon Layers for Vias dialog comes up. Please check the Layer 3 (see Figure 6.32).
Select OK to continue. The 1st Automatic Vias procedure is defined. It is list in the Automatic Vias list box on the right (see Figure 6.33). The No.5 layer on the Layer Definitions is also changed. It defines a procedure MGRID will take after you select OK button. The procedure is that MGRID uses the polygons on the No.5 Layer at Z = 80 to build holes on the No.3 Layer at Z = 40. Because No.3 Layer is the only passive layer for this procedure, MGRID will not build any via. In case, you checked more than 1 layer, there will be multiple passive layers in this procedure. In this case, MGRID will build vias between the passive layers.
Figure 6.30 The Import Data Option dialog after opening the: vias_on_layers.ctp file.
Figure 6.31 The illustration of the layer configuration, the top view and 3D view.
Step 6 Click at the: “No. 6 Symbol = L006,…” in the Layer Definitions list box to highlight it. Select the Insert button again. The Edit Polygon Layers for Vias dialog comes up. Pleas check the Layer 2 and Layer 4. Select OK to add the Automatic Vias procedure into the list. The procedure defines that MGRID will use the polygons on the No.6 layer to build vias between the two passive layers: No.2 and No.4 layers (the trace layers).
Step 7 Click at the: “No.7 Symbol = L007,…” in the Layer Definition list box. Select the Insert button again. The Edit Polygon Layers for Vias dialog comes up. Check the Layer 1 and Layer 3. Select OK to add the procedure into the list. Basically, the procedure defines that MGRID will use the
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polygons on the No.7 layer to build vias between the 2 finite ground plane layers. Check the Open Cap option. We will get the Import Parameters dialog as shown in Figure 6.34.
Figure 6.32 The Import Parameters dialog and the Edit Polygon Layers for Vias dialog.
Figure 6.33 The Import Parameters dialog with the 1st Automatic Vias procedure defined.
Step 8 If we select OK on the Import Data Options dialog, MGRID will import the polygons into the right layers and build the holes and vias as instructed. However, we would like to save the data into a template file first for future use.
Select the Save button in the Template File and save it as: .\ie3d\practice\vias_for_layers2.ctp.
Select Cancel button to cancel the process. We are going to demonstrate how we can use the vias_for_layers2.ctp to define the layers and the vias automatically.
6-26 Figure 6.34 The Import Parameters dialog with all Automatic Vias procedures defined by Step 7.
Figure 6.35 The 3D view of the imported structure imported and processed.
Step 9 Repeat Steps 1 and 2. Then, please select Load button on the Template File section. Select the file: .\ie3d\practice\vias_for_layers2.ctp file we just created. MGRID will set the layers and have the automatic vias procedures automatically defined.
Step 10 Select OK and MGRID imports all the polygons on different layers. Then, it will automatically build the holes and vias (see Figure 6.35 and Figure 6.36).