antennaModels

antennaModels(
( "t_name"
  t_constraintName(
  ( t_ratioName tx_layer f_value )
)
…

( "factors"
  ( cumulativeRoutingPlusCut lx_layer )
  ( area  lt_layer f_value )
  ( diffPlus  lt_layer f_value )
  ( diffMinus  lt_layer f_value )
  ( diffAreaReduce  lt_layer ( ( f_area f_value ) … )
) ;factors

) ;antennaModels

Defines antenna ratios for up to four oxide types, each specified in its own antennaModels group.

Antenna models must be specified only in the antennaModels constraint category of the foundry constraint group. The antenna models all follow the same syntax when specified in the ASCII technology file. For each antenna model, you can specify the antenna, cumulativeMetalAntenna, cumulativeViaAntenna, and cumPerLayerAntenna constraints, each of which specifies the areaRatio and diffAreaRatio ratios.

factors

Alternatively, you can specify factors by using the following syntax:

factors(
( cumulativeRoutingPlusCut lx_layer )
( area  lt_layer f_value )
( diffPlus  lt_layer f_value )
( diffMinus  lt_layer f_value )
( diffAreaReduce  lt_layer ( ( f_area f_value ) … )

) ;factors

This is because factors is a SKILL technology class function and can be defined as "name(…)" or "(name …)".

Types

• Add cut layer cumulative area ratio to metal cumulative area ratio
  The calculation of the cumulative metal area ratio for a particular metal layer adds the partial cut area contribution from the cut layer below the layer in question as well as the partial metal area from the metal layer. Similarly, for the cumulative cut area ratio, the partial metal area for the metal layer below is added to the contribution from the partial cut area of the cut layer. The use of this antenna model is indicated by the cumRoutingPlusCut attribute on the layer.

  Mi_CAR = Mi-1_CAR + Mi_PAR + C(i, i-1)_PAR

  and

  C(i, i-1)_CAR = C(i-1, i-2)_CAR + C(i, i-1)_PAR + Mi-1_PAR

  where, Mi_CAR is the cumulative metal area ratio for metal layer i, Mi_PAR is the partial metal for the same metal layer, and C(i, i-1)_PAR is the partial cut area for the cut layer below Mi.
• Subtract diffusion area from antenna area
  The diffusion area is subtracted from the metal or cut area in the calculation of the antenna ratio for metal and cut layers.

  antenna ratio = (metal_area - diff_minus_factor * diff_area) / gate_area

  antenna ratio = (cut_area - diff_minus_factor * diff_area) / gate_area

  The diffusion area that is subtracted from the area is controlled by the diff_minus_factor. The default value of this factor is 0.
• Add diffusion area to gate area
  The diffusion area is added to the area of the gate in the calculation of the antenna ratio.

  antenna ratio = metal_area / (gate_area + diff_plus_factor * diff_area)

  Because the contribution from the diffusion area is taken into account in the antenna ratio, the antenna diff ratio (metal_area/diff_area) is not required to be calculated. This applies to both the layer antenna ratios and the cumulative antenna ratios for both metal and cut layers. The default value of diff_plus_factor is 0.
• Reduce metal area with PWL diffusion factor
  The metal area (and possibly cut area if the add via area of to the metal area model is applied) is multiplied by a factor called diff_metal_reduce, which depends on the diffusion area. The diff_metal_reduce factor applies to the metal_area before the contribution from diff_minus_factor is subtracted. This diff_metal_reduce factor is a piecewise linear model based on the diffusion area and typically ranges from 0 to 1. The default value is 1. A similar factor can be defined for cut and cumulative antenna ratios.

  antenna ratio = metal_area * diff_metal_reduce / gate_area

• Area factor and side area factor
  The default value for area_factor is 1. Because the antenna ratio can either be side or non-side at one time, there is a need to store only one area_factor, either the side or non-side factor. A Boolean operator indicates whether the factor is used for the side area factor.

  antenna ratio = area_factor * metal_area / gate_area

  or

  antenna side ratio = area_factor * metal_side_area / gate_area

• Combined antenna models
  Adding all possible factors, the antenna ratio for a metal layer can be calculated as follows:

  antenna ratio = (area_factor * metal_area * diff_reduce_factorPWL - diff_minus_factor * diff_area) / (gate_area + diff_plus_factor * diff_area)

  For a cut layer, the antenna ratio is calculated as follows:

  antenna ratio = (area_factor * cut_area * diff_reduce_factorPWL - diff_minus_factor * diff_area) / (gate_area + diff_plus_factor * diff_area)

  These ratios are associated with a particular layer. However, when performing cumulative antenna calculations, the appropriate layer antenna factors should be used. These are not associated with particular oxide models.

Parameters

t_name	The antenna oxide model name. Valid values are as follows: default: Antenna oxide1 model second: Antenna oxide2 model third: Antenna oxide3 model fourth: Antenna oxide4 model
t_constraintName	The name of the constraint being defined. Valid values are as follows: antenna specifies the maximum antenna ratios for one or more antenna models for the specified layer. cumulativeMetalAntenna specifies the maximum antenna ratios for one or more antenna models for area values accumulated through all the poly and metal layers attached to a gate. cumulativeViaAntenna specifies the maximum antenna ratios for one or more antenna models for area values accumulated through all the cut and via layers attached to a gate. cumPerLayerAntenna specifies the maximum antenna ratios for one or more antenna models for area values accumulated for the specified layer.
t_ratioName	The name of the antenna ratio, areaRatio or diffAreaRatio.
tx_layer	The layer on which the antenna ratio constraint is applied. It must not be specified when t_constraintName is cumulativeMetalAntenna or cumulativeViaAntenna. Type: String (layer name) or Integer (layer number)
f_value	The areaRatio or diffAreaRatio value. areaRatio has the following syntax: f_value ['side] where, f_value is the area ratio 'side specifies that the side calculation be applied. The default is "no side". diffAreaRatio has the following syntax: f_value | ((f_area f_value)…) ['side] where, f_value is the diffusion area ratio, specified as an absolute value or based on the total diffusion area, if specified. f_area is the total diffusion area. 'side specifies that the side calculation be applied. The default is "no side".

Example

antennaModels(
;( model
 ( "default"
    antenna(
     ;(ratioName layer value)
  ( areaRatio METAL1 450.0 )
  ( diffAreaRatio METAL1 ((0.45 0.4)(0.55 0.6)) )
  ( areaRatio VIA1 0.344 )
  ( diffAreaRatio VIA1 ((0.44 0.5)(0.57 0.8)) )
 ) ;antenna
 cumulativeMetalAntenna(
  ;( ratioName value )
   ( areaRatio 0.544 'side )
   ( diffAreaRatio 0.888 )
 ) ;cumulativeMetalAntenna
 cumulativeViaAntenna(
  ;( ratioName value )
  ( areaRatio 0.654 'side )
  ( diffAreaRatio 0.884 )
 ) ;cumulativeViaAntenna
 );default

 ( "second"
    antenna(
     ;( ratioName layer value )
  ( areaRatio METAL1 1.345 'side )
  ( diffAreaRatio METAL1 ((0.455 0.4)(0.555 0.65)) )
 ) ;antenna
 cumulativeMetalAntenna(
  ;( ratioName value )
  ( areaRatio (3.564 nil) )
  ( diffAreaRatio 7.888 )
 ) ;cumulativeMetalAntenna
 cumulativeViaAntenna(
  ;( ratioName value )
  ( areaRatio (7.654 nil) )
  ( diffAreaRatio 1.884 )
 ) ;cumulativeViaAntenna
 ) ;second

 ( "third"
    antenna(
     ;( ratioName layer value )
  ( areaRatio METAL1 0.343 )
  ( diffAreaRatio METAL1 ((0.43 0.3)(0.53 0.6)) )
 ) ;antenna
 cumulativeMetalAntenna(
  ;( ratioName value )
  ( areaRatio 9.765 'side )
  ( diffAreaRatio 0.188 )
 ) ;cumulativeMetalAntenna

 cumulativeViaAntenna(
  ;( ratioName value )
  ( areaRatio 3.22 )
  ( diffAreaRatio ((0.421 0.4)(0.7 0.64)(0.81 0.59)) ) 
 ) ;cumulativeViaAntenna
 ) ;third

 ( "fourth"
    antenna(
     ;( ratioName layer value )
  ( areaRatio METAL2 0.645 'side )
  ( diffAreaRatio METAL2 ((0.47 0.4)(0.55 0.7)) )
 ) ;antenna

 cumulativeMetalAntenna(
  ;( ratioName value )
  ( areaRatio 0.6 )
  ( diffAreaRatio ((0.127 0.23)(0.32 0.7)) ) 
 ) ;cumulativeMetalAntenna

 cumulativeViaAntenna(
  ;( ratioName value )
  ( areaRatio 9.67 )
  ( diffAreaRatio 0.684 )
 ) ;cumulativeViaAntenna
 ) ;fourth
) ;antennaModels 

cumPerLayerAntenna(
    ( areaRatio "via1" 0.64 'side )
    ( diffAreaRatio "via1" ((30 0.3888) (25 0.6774)) 'side ) 
) ;cumPerLayerAntenna

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