search

KLayout / klayout

KLayout Main Sources
http://www.klayout.org
GNU General Public License v3.0
745 stars 192 forks source link

LVS soft connections: making a soft connection to a device terminal disconnects the device #1691

Closed klayoutmatthias closed 2 months ago

klayoutmatthias commented 2 months ago

This can happen through global connections which are made inside the device. For example:

# NMOS transistor device extraction
extract_devices(mos4("NMOS"), { "SD" => nsd, "G" => ngate, "W" => bulk,
                                "tS" => nsd, "tD" => nsd, "tG" => poly })

...

soft_connect_global(bulk, "SUBSTRATE")

In this scenario, the "B" terminal of the "NMOS" device gets disconnected.

The workaround is not to use soft connections to global nets from terminal-target layers. This does not make sense anyway, as there is no way to create a separate connection to the terminals in that case.