Virtuoso XL Layout Editor User Guide

Setting Up Device Abutment for Virtuoso XL Layout Editor

MOS Abutment without a User-defined abutFunction

Another way to process abutment and unabutment without creating an abutFunction callback, is to use the abutMosStretchMat property. The abutMosStretchMat property is used with the autoAbutment properties to define abutment.

This section describes the autoAbutment properties that you will have to add to pcells to use autoAbutment on standard MOS pcells without having to define your ownuser-defined abutFunction.

autoAbutment Properties

Beyond creating specific parameters in the pcells and named diffusion shape pins, you will also have to add the following properties on the shapes the pins are created on. The autoAbutment properties specify if the pcells can abut.

abutClass = Abutting pins of the same abutClass are able to abut.

abutAccessDir = Defines the directions the pins are able to abut.

abutGateNet = Defines the name of the net the gate shapes are on.

abutCondInclusion = Defines the name of the boolean property that adds or removes contact shapes over the diffusion pin.

The abutMosStretchMat Property

The abutMosStretchMat property is made up of nine rules that stretches the material toward or away from the gate when the instance is altered for abutment.

abutMosStretchMat = Defines the name of the float property and the nine rules to control the diffusion enclosure of the poly gate.

list(t_stretchParamName list(“abutFlush” f_value) list(“abutGateSpaceSeries” f_value) list(“abutGateSpaceParallel” f_value) list(“abutEncloseGate” f_value) list(“abutEncloseContact” f_value) list(“abutSmallerSeries” f_value) list(“abutSmallerParallel” f_value)

list(“abutEncloseDogBoneContact” f_value)

Virtuoso XL Layout Editor User Guide

Setting Up Device Abutment for Virtuoso XL Layout Editor

list(“abutMinContactWidth” f_value)

)

abutMosStretchMat Rules for MOS Abutment

The illustration below shows the various MOS diffusion extension rules for the abutMosStretchMat property list.

Below are a description of the abutMosStretchMat diffusion extension rules.

A = abutFlush (Not shown). The abutFlush rule is applied to the pin not moving when an abutment event is occurring between two pins of equal width.

B = abutGateSpaceSeries. The abutGateSpaceSeries rule is applied to the moving pin when an abutment event is occurring between two pins, of equal width, and a contact is not needed between the gates. The abutFlush rule is applied to the non-moving pin being abutted.

C = abutGateSpaceParallel. The abutGateSpaceParallel rule is applied to the moving pin when an abutment event is occurring between two pins, of equal width, and a contact is needed between the gates and the pin widths are greater than or equal to the abutMinContactWidth rule. The abutFlush rule is applied to the non-moving pin being abutted.

D = abutEncloseGate. The abutEncloseGate rule is applied to the larger of two abutting pins when a contact is not needed between the gates. The abutSmallerSeries rule is applied to the smaller of the two pins being abutted.