Connections Recognized by the Extractor
When extracting connectivity, Layout XL detects:
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Shorts and opens on nets by recognizing connections between adjacent shapes, vias, and instance pin figures, including microwave objects. These connections can exist on the same layer or on electrically connected layers, as reported by the Diagnostic Report, which is available through the Connectivity Form.
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Instance pin figures are considered by the extractor even when the default extract stop level is
0. The connectivity checked in this case is that of the nets attached to the corresponding instTerms. - Connectivity of shapes inside global routes is not extracted because these represent coarse routing, which is usually only used to get an estimate about the congestion of the design.
- An empty net—a net that does not own a figure, an instTerm, a terminal, or a non-empty constraint —can be deleted by the extractor.
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Instance pin figures are considered by the extractor even when the default extract stop level is
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Connections between a shape and a label, where the label is the source of connectivity for the shape, are recognized. Such shapes are considered to be sticky shapes that have the
lxStickyNetproperty, therefore, they stay connected to the net referenced by the label text. The label can be attached to the shape or it can be a stampLabel overlapping the shape.
See Connectivity from Attached Labels to Consider During Extraction and Connectivity from stampLabels During Extraction. - Connections between dedicated abutment shapes (dummy poly or dummy diffusion) of overlapping devices, even if the default extract stop level is 0, are recognized.
- Connections to instances and nets within a transparent layout hierarchy.
When extracting designs that have been edited outside Layout XL, the connectivity extractor silently cleans up the unmatched instance terminals that have no associated terminal in the cell master. This means that you can be asked to save your design, even though nothing has visibly changed.
Assigning Connectivity to a Via
You can assign connectivity directly to a via in the same way as you assign connectivity to paths, polygons, and rectangles. The lxStickyNet property is automatically added to the via, which retains the net assignment until you remove the property or override it with a new net assignment.
If you remove the lxStickyNet property, Layout XL assigns connectivity to the via based on overlaps.
Related Topics
Transparent Layout Hierarchy Generation
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