cumulativeViaAntenna (oacCumViaAntenna)


Description

The built-in simple constraint definition oaCumViaAntenna specifies the maximum antenna ratios for one or more antenna models (oxide thicknesses) for area values accumulated through all the cut and via layers attached to a gate. This constraint holds a value that specifies the maximum allowed ratio of this cumulative sum to the gate area (gateAreaRatio), and specifies how that maximum ratio changes if a diode is present on the wire (diodeAreaRatio).

Constraint at a Glance

Constraint type: oaSimpleConstraint
Value types: oaAntennaRatioValue, oaAntennaRatioArrayValue
Database types: oaTech
Object types: oaAppObject

Values

The following value types are supported by this constraint:

Manufacturing Reasons

Antenna rules limit the electrical charges that build up during metal processing, such as plasma etching processes. Without these limits, the probability that the built-up charges might break through gate oxides increases greatly. Some processes have multiple gate oxides. These different thicknesses allow for different amounts of charge resistance. This is why multiple oxide models are available.


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