Hi @User and All, I got FOM density check failed in the tapeout step. What is the cause of this error and how to fix it? Thanks!

[12/04/21 09:56:45 PST] FAILED STDOUT: {{Project Git Info}} Repository: <https://github.com/nguyendao-uom/fuserisc_ver2.git> | Branch: HEAD | Commit: b73e826d75d27b380a9e15db24919e03a1dc6716 STDOUT: {{Extracting GDS}} Extracting GDS Files STDOUT: {{Project GDS Info}} user_project_wrapper: b5422e3fdbec071f94696e2d2df62f112925e789 STDOUT: {{START}} Tapeout Started STDOUT: {{Step Update}} Generating Final Layout: Step 1 of 5 STDOUT: {{Step Update}} Generating Final Layout: Step 2 of 5 STDOUT: {{Step Update}} Generating Final Layout: Step 3 of 5 STDOUT: {{Step Update}} Generating Final Layout: Step 4 of 5 STDOUT: {{Step Update}} Generating Final Layout: Step 5 of 5 STDOUT: Final GDS File caravel_000327ab.gds sha1sum: a283fe63ef47ab0fecb08945283a4f7abdc38192 STDOUT: {{Step Update}} Converting Final Layout from GDS to OAS STDOUT: Final OAS File caravel_000327ab.oas sha1sum: 6e3c792ebfdd4e5525cf4663b465e68160f7d27c STDOUT: {{Step Update}} Executing Check 1 of 2: Klayout Metal Minimum Clear Area Density STDERR: [ WARN ] MET Density Check Result: GDS has 0 DRC violations. STDOUT: {{Step Update}} Executing Check 2 of 2: Klayout Field Oxide Mask Density STDERR: [ WARN ] FOM Density Check Result: GDS has 246 DRC violations. STDOUT: {{FINISH}} Executing Finished, the full logs can be found in u5221_nguyenv/design/fuserisc2/jobs/tapeout/439285a6-1555-4742-82bf-0d677dc3add6/logs

@User You can cross-check log/met-density.log All the Metal density should be more than 0.4 for tape-out check to pass. If the issue is in li1_ca_density < 0.4 .. One of the option is to reduce the IP free space. When there is more free space, then more DECAP_CELL and FILL_CELL will be their in your design. You need to reduce this ..

Hi @User, it’s about FOM density not metal density. Any idea on FOM density? Thanks

Check 1 of 2: Klayout Metal Minimum Clear Area Density STDERR: [ WARN ] MET Density Check Result: GDS has 0 DRC violations. STDOUT: {{Step Update}} Executing Check 2 of 2: Klayout Field Oxide Mask Density STDERR: [ WARN ] FOM Density Check Result: GDS has 246 DRC violations.

@User FOM is diff+tap+fill. one of the common ways to end up low on FOM is using too many fill cells. these can be replaced with either decap or the ef modified fill cells that include diffusion.