Using a TRACE PROPERTYSVRF statement that doesn't use the default w property for both source and layout length properties generates a properties missing message in the LVS Report for Calibre nmLVS.
TRACE PROPERTYmn wdv wdv 0.1
Properties Missing on Instances:
property wdv not found on MM1 (MN)
The combination of all these factors contribute to whether the "property" "not found on" message is issued by nmLVS in terms of length and width comparisons:
- The property names used for length (l) and width (w) in the Source netlist
- The property names for l and w in the DEVICE statement
- The property names for l and w as defined in the TRACE PROPERTY statement
- The LVS SPICE STRICT WL option
In a typical scenario the DEVICE statements in a rule file will contain properties l and wto represent length and width. As such, the extracted layout netlist will contain computed length and width values in the form l=__ and w=__ . In the same way, the source netlist typically contains length and width values in the form l=__ and w=__ as well. Using either the default LVS SPICE STRICT WL NO or LVS SPICE STRICT WL YES along with TRACE PROPERTY statements that make reference to l and w for both the layout and source allows everything to work correctly.
However when you substitute property names other than l and w in the TRACE PROPERTY statement, perhaps to reflect the property names as defined in the DEVICEstatements of the rule file and/or the property names as defined in the source netlist, using the default LVS SPICE STRICT WL NOstatement will result in the missing property messages. Naming the length and width properties any name that begins with an l and w respectively is acceptable but LVS SPICE STRICT WL NOwill cause Calibre nmLVS to see them as l and w none the less.
Options to correct this problem include:
- The consistent use of l and w in DEVICE and TRACE PROPERTYstatements as well as in the source netlist. This option works with both the default LVS SPICE STRICT WL NO and the user specified LVS SPICE STRICT WL YES statements.
TRACE PROPERTYmn w w 0.1
LVS SPICE STRICT WL NO
- Continuing to use unique length and width property names while at the same time using LVS SPICE STRICT WL YESinstead of the default NO or not specifying the option at all.
TRACE PROPERTYmn wdv wdv 0.1
LVS SPICE STRICT WL YES
Note 1: To see the actual property names and values that are being compared, use the following two statements in your rule file to write out the files and view them:
LVS WRITE SOURCE NETLIST source.net
LVS WRITE LAYOUT NETLIST layout.net
Note 2: To verify the properties are compared, set up a test source netlist, setting wdv to a large number such as 99 and running Calibre nmLVS. Note the failed property comparison in the LVS REPORT.
Additional information concerning each of the statements above (DEVICE, LVS SPICE STRICT WL, and TRACE PROPERTY) can be found in the Standard Verification Rule Format (SVRF) Manual.