wafer iconFrequently Asked Questions

Extract to Spice

How do I extract soft connections?

You can configure the extractor to write special devices for each connection to a well or substrate, called "soft connections." These special devices must be included in the netlist for LVS to identify soft-connected nodes. By convention, these devices are 0�� resistors with designated model types, such as R_WELLCONTACT and R_SUBSCONTACT.
To write special devices for soft connections, make the following changes in the extract file:
! To detect ohmic contacts to well and substrate, create two additional derived layers:
ohmic well contact := n well wire AND ndiff
ohmic substrate contact := subs AND pdiff
! Do not connect wells and substrates to diffusions through ohmic contacts. Look through the extract
file and delete lines like the following:
connect(n well wire, ndiff, ndiff)
connect(subs, pdiff, pdiff)
! Add device recognition statements for the ohmic contact special devices (resistors). For example:
# Well contact
device = RES(
RLAYER=ohmic well contact;
Plus=n well wire;
Minus=ndiff;
MODEL=WELLCONTACT;
)
# substrate contact
device = RES(
RLAYER=ohmic substrate contact;
Plus=subs;
Minus=pdiff;
MODEL=SUBSCONTACT;
)

How can I extract devices with multiple base or collectors?

You need to build a subcircuit for those devices.

How do I extract the Area/Perimeter of a MOSFET in L-Edit?

In the past, L-Edit had an option in the Extract dialog box to extract the Area/Perimeters of MOSFET. Starting with L-Edit V7, this option was removed. If the Area/Perimeter data is desired, it needs to be set up in the extract definition file. For more details, please refer to the manual on the extract section or take a look at the technology setup file we provided with L-Edit.

 

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