What does a basic standalone IC Validator DRC and LVS run look like?

Short Answer

A standalone run is one shell command: icv (ICV), the layout file, its format, the top cell and the runset. For DRC that is icv -i top.gds -f GDSII -c top drc_runset.rs (ICV). For LVS you use the LVS runset and add the reference netlist with -s top.sp -sf SPICE (ICV). The runset, not a command option, decides whether the run is DRC or LVS.

Technical Explanation

• The syntax is icv [command-line-options] runsetfile (ICV). The runset is the last argument and is required, except for netlist-versus-netlist flows.
• -i (ICV) overrides the library name given in the runset's library() (ICV) function. When you use it, the runset's library name and merge list are completely replaced, so list every file you need.
• -f (ICV) overrides the library format: GDSII, Milkyway, NDM, OASIS or OpenAccess. -c (ICV) overrides the top cell; -c "*" (ICV) lets the tool find the top cell in a GDSII or OASIS file, but the guide says not to use it with LVS runsets, that is, runsets that call compare() (ICV).
• -s (ICV) overrides the schematic file for LVS. When you use it you must also give -sf (ICV), which sets the format to SPICE, VERILOG or ICV.
• DRC versus LVS is decided by the runset. A DRC runset contains rule checks; an LVS runset contains extraction and compare() (ICV). Adding -s (ICV) to a DRC runset does not turn it into LVS.
• Outputs go to the working directory, with detailed data under run_details (ICV). The main files are cell.RESULTS (ICV), cell.LAYOUT_ERRORS (ICV), cell.LVS_ERRORS (ICV) for LVS and cell.sum (ICV). If the tool itself fails, the exit code is reported in cell.err (ICV).
• This standalone run needs only the stream file, not the ICC2 design library, so it is the check you run on the exact file going to the foundry.

What To Check

• The top cell in cell.RESULTS (ICV) run information matches the intended cell.
• The runset path and version recorded in the call line.
• For LVS, that -s (ICV) points to the reference netlist from the same database state as the GDS.
• The header verdict, then rules not executed.

Healthy, Suspicious & Hard-stop Results

• Healthy (illustrative): DRC RESULTS: CLEAN (ICV) and LVS LVS Compare Results: PASS (ICV) with extraction CLEAN, top cell and runset versions as expected.
• Suspicious (illustrative): Clean results but the call line shows a runset path in someone's home directory rather than the project release area.
• Hard stop: RESULTS: RUN ABORTED (ICV), or a schematic-file-not-found error for LVS.

What The Interviewer Is Testing

• The candidate should know the runset decides the check type.
• Remembering that -s (ICV) needs -sf (ICV).
• Knowing which files a run produces and which to open first.

Follow-up Question & Model Response

"What happens to the runset's library settings when you pass -i on the command line?"

Candidate Model Response: The -i (ICV) option completely redefines the library name and the merge-libraries list from the runset's library() (ICV) function. None of the original values remain. If the runset merged a separate IO GDS and I pass only my block GDS with -i (ICV), that merge is lost. I either repeat -i (ICV) for every file or keep the merge in the runset.