validLayers – Substrate Layer Specification

You can use the validLayers constraint to define the substrate as extractable when the Verify connections to substrate and set well layers as soft option in the Connectivity form – Connectivity – Verify tab is enabled.

Consider the following derived layer definitions in the validLayers constraint:

(StoppedSubstrate 10000 (substrate 'not Nwell))

(validLayers (StoppedSubstrate))

The constraint definition indicates that the:

• Nwell and substrate are extractable layers
• substrate is being stopped by Nwell
• The polarity of the substrate is p-type since it is stopped by an n-type well layer

When the Verify connections to substrate and set well layers as soft option is enabled:

• substrate should be stopped by a well layer. If that is not the case, a warning message is issued and substrate connectivity extraction is disabled.
• substrate should be stopped by a single well layer. If the substrate is stopped by several well layers of different polarities, a warning message is issued and substrate connectivity extraction is disabled.
• To derive the polarity of the substrate, the extractor uses the validLayers constraint definition, which indicates that the substrate should be considered p-type if the stopping well layer is n-type and vice versa. If the substrate is not defined as stopped by a well layer, the extractor considers the standard via definitions in standardViaDefs where the well or substrate is set as substrate. For more information, see Substrate Layer Connectivity.

Related Topics

validLayers

validLayers – Layer-Purpose Pairs Specification

validLayers – Stop Layers Specification

validLayers – Enclosed Stop Layers Specification

validLayers – Color-Dependent Stopped and Stop Layers Specification

validLayers – Bulk Area Layers Specification

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