Layout Editor Rules

The leRules section of the technology file specifies the layers that are listed in the Layer Selection Window (LSW) assistant and the order in which they are listed.

Layer Definitions

The layerDefinitions section of the technology file defines the layers used in the current technology. All the layers used in your design must be defined in this section.

Layer Rules

The layerRules section carries the functions table, which specifies the layers used in the current technology and rules such as the function of each layer and its maskNumber.

Here is an example:

functions(
 ;( layer          function         [maskNumber] )
 ;( -----          --------          ----------  )
  ( NWELL          "nwell"           1           )
  ( PWELL          "pwell"           2           )
  ( DIFF           "diff"            3           )
  ( NIMP           "nplus"           6           )
  ( PIMP           "pplus"           7           )
  ( DIFF2          "pdiff"           8           )
  ( DIFF           "diff"            9           )
  ( POLY           "poly"            10          )
  ( LI             "li"              11          )
  ( CONT           "cut"             12          )
  ( METAL1         "metal"           13          )
  ( VIA1           "cut"             14          )
  ( METAL2         "metal"           15          )
);functions

Constraint Groups

A constraint group lets you specify the different sets of design constraints to be applied under different design circumstances or for different design objects. This allows the flexibility to experiment with more or less stringent process rules at different stages of the design process.

You can group together any set of constraints into a constraint group, which can then be applied to any design associated with the technology library.

Devices

The two main types of technology devices used in Layout XL are vias and multipart paths.

Specifying Vias

Vias are required by the Create – Via and Create – Wire commands and by the Routing – Start Router command. Vias are defined by using standardViaDefs, which are equivalent to the symContactDevices used in previous releases; and customViaDefs, which reference a via cellview.

All the vias used in your design must be defined in the viaDefs section of the technology file and listed in the validVias constraint in the virtuosoDefaultExtractorSetup constraint group. Any via cellviews referenced by customViaDefs must also exist.

Specifying Multipart Paths

Multipart path templates are defined in the multipartPathTemplates section in the technology file.

Physical Rules

Physical rules are specified in the foundry constraint group.

The minimum requirement for Layout XL is the minWidth constraint which is used by the Create – Shape – Path and Create – Wire commands to determine the minimum width of objects and the default width of a wire.

For example,

constraintGroups(
 ; ( group                             [override] )
 ; ( -----                              --------  )
   ( "foundry”
   ;  physical constraints
      spacings(
      ;( constraint     layer1     layer2     value )
      ;( ----------     ------     ------     ----- )
       ( minWidth       METAL1                0.02
      );spacings
     );foundry
);constraintGroups

Connectivity Rules

The connectivity stack is a representation of the extractable layers and the associated electrical connections used by the Layout XL connectivity extractor.