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Edit Mapping Layer dialog box
Cadence Virtuoso Interface - Substrate Section - Substrate File Setup dialog box
Cadence Virtuoso
The name and number of the Virtuoso layer is displayed. Note that the layer name and number have no relationship to Sonnet’s dielectric layer number or metallization level number. You may not edit this entry. If you wish to map this layer to the Sonnet circuit geometry, then click on the Map checkbox.
Sonnet
These controls affect how the layer is mapped to the Sonnet project.
Drawing Type: This maps objects on the Virtuoso layer identified above to the Sonnet project. This drop list allows you to select what type of object should be input to the Sonnet project. Select Metal for metalization, or Via for a via polygon from the drop list. The appearance of the dialog box changes depending on which Drawing Type is selected.
Metal Fill Type (Mesh): This drop list appears when the Drawing Type is Metal and controls the fill type in Sonnet for any metal polygons that are present on the Virtuoso layer. The “fill type” of a polygon is defined as the type of subsection used by the solver at the edges of a polygon. The four options in the drop list are defined as follows:
Metal Fill Type |
Description |
| Default | The metalization will use the default fill type selected in the Cadence Virtuoso Interface. |
| Staircase | Provides the best rectangular fit to the metalization edge. Staircase subsections are used in the middle of a polygon for all choices. Sonnet defaults to “staircase” edge fill for all new metal structures. |
| Diagonal | Allows triangular as well as rectangular subsections. This provides a better fit to diagonal edges but requires more analysis time. |
| Conformal | This applies conformal meshing to the selected polygon(s). This allows for larger conformal sections which model curved edges more efficiently |
Via Fill Type (Mesh): This drop list appears when the Drawing Type is Via and controls the fill type in Sonnet for any via polygons that are present on the Virtuoso layer. The “fill type” of a via polygon determines how the via polygon is subsectioned. The four options in the drop list are defined as follows:
Via Fill Type |
Description |
| Default | The via will use the default fill type selected in the Cadence Virtuoso Interface. |
| Ring | The via is modeled as a one cell wide wall of via subsections and is hollow in the middle, containing no metal. This is the Default in Sonnet and most commonly used. Good for most applications. Moderate memory use. |
| Vertices | Models the via by placing a single cell wide via subsection at each vertex of the polygon. Use when the location and shape of the via is not critical. Relatively low memory use. |
| Center | A single cell wide via subsection is placed in the center of the via polygon. Use when location, shape, and size of the via is unimportant. Lowest memory use. |
| Full | This meshing fill models the via as solid metal. All subsections in the interior of the via are filled with metal extending the length of the via. Use only when simulating solid vias at low frequency and the skin depth is larger than the cell size. |
| Bar | This meshing fill identifies the via as being a Bar via. Use this fill model for vias within stacked multi-level conductors where the vias carry horizontal currents. During the analysis, multiple adjacent bar vias are merged into one wider via to save memory and processing time. When the bar vias are grouped and simplified by the analysis engine, they are meshed using a Vertices fill. |
Metal Material: This drop list appears when the Drawing Type is Metal. Select the metal material type you wish to use for the object in the Sonnet project translated from the Virtuoso layer. The choices available depend on what metal materials have been defined. Materials are defined using the Material Setup dialog box.
Via Material: This drop list appears when the Drawing Type is Via. Select the via material type you wish to use for the object in the Sonnet project translated from the Virtuoso layer. The choices available depend on what via materials have been defined. Materials are defined using the Material Setup dialog box.
Drawing Level: This specifies the level in the Sonnet project where you wish to place the object being input from Virtuoso. The top level is number 0. To put metal on the ground plane, for via placement, set the level number to “GND”. If the object is a via, this defines the origin of the via. The number of levels are defined using the Dielectric Setup dialog box.
To Drawing Level: This drop list only appears if the Drawing Type is a Via. Select the level to which you wish the via to extend. The origin of the via is selected in the Drawing Level drop list. Values range from GND for ground up to TOP for the box top.
Add Via Pads: Adds a Full metal pad to the top and bottom of any via which does not already have a pad at the bottom or top in the geometry being input. The pad is created using the same metal type as the via. This check box only appears when the Drawing Type is Via.
Use Edge Mesh: When using the Edge Mesh option, all Manhattan polygons (no diagonal edges) are treated as if they were non-Manhattan polygons. In other words, the edge subsections are always one cell wide regardless of X Min or Y Min. This field is applied as a global setting for all polygons on this drawing level. When used in conjunction with large X Min or Y Min values, this option can be very useful in reducing the number of subsections but still maintaining the edge singularity. This is very often a good compromise between accuracy and speed. This check box only appears when the Drawing Type is Metal.
XMin, XMax, YMin, YMax: These fields only appear when the Drawing Type is Metal.The analysis engine allows you to control how cells are combined into subsections for each polygon. This is done using the parameters “X min”, “Y min”, “X max” and “Y max.” These fields are applied to all polygons on this level.
For a detailed
discussion of these parameters and how they affect subsectioning in Sonnet,
please refer to "Changing the Subsectioning of a Polygon" in
the "Subsectioning" chapter in the Sonnet User’s Guide.
Import/Export Layer Mapping Options
When your layout is translated to a Sonnet project, Technology Layers are created based on the mapped CDS Layer. The information entered in this section of the dialog box is associated with the Technology Layer. If the Sonnet project is subsequently exported to a DXF file, GDSII file or Gerber files, the name(s) entered here are used to name the layers in the resulting translated files. It is recommended that you enter the name of the CDS Layer here which will allow you to track objects in the translated files. These fields are all optional.
DXF Layer: This field specifies the name of the DXF layer assigned to the selected Technology Layer(s) to which the CDS Layer is mapped. If the Sonnet project is later exported, then the resulting DXF layer created from the Technology Layer will use this name. This can be useful as a reminder of the source of this layer. This field is optional.
GDSII stream: This field specifies the number of the GDSII stream assigned to the selected Technology Layer(s) to which the CDS Layer is mapped. If the Sonnet project is later exported, then the resulting GDSII stream created from the Technology Layer will use this name. This can be useful as a reminder of the source of this layer. This field is optional.
GDS Data Type: This field specifies the data type of the GDSII stream for the selected Technology Layer(s) to which the CDS Layer is mapped. A GDSII stream may contain more than one type of object, such as metal polygons and via polygons. Each object is assigned a data type. If the Sonnet project is later exported, then the resulting GDSII stream created from the Technology Layer will use this data type. This can be useful as a reminder of the source of this layer. This field is optional.
Gerber Filename: This field specifies the Gerber file assigned to the selected Technology Layer(s) to which the CDS Layer is mapped. The filename does not require an extension. If the Sonnet project is later exported, then the resulting Gerber file created from the Technology Layer will use this name. This can be useful as a reminder of the source of this layer. This field is optional.