My MPW-6 tapeout run fails on fom density check, File: klayout_fom_density.log fom density below 0.33 : 478/2730 is 0.3286 for tile ((490,160;1190,2310)) area: 490000 Is any one facing Similar issue ? Is this issue related to caravel or User area ? How to fix this ?

You haven’t stated which layers fail density, but it could be due to fill cells in the digital part. They are known to cause too high

li1

density. There are a few workarounds. See https://skywater-pdk.slack.com/archives/C01EX4ATEKF/p1646991226741249

It's not showing as LI1 layer

It's the

fom

layer - diffusion.

How to fix this failure ?

This is the first I've heard of this type of error, so all my suggestions are just guesses. First, look at the diffusion (tap, diff, and fom/dummy [22/23?] layers) in the error region of

caravel_0006c63f

. Normally, fill patterns are generated to avoid density errors. See if there is a large area with out diffusion patterns. The rule requires at least 33% density in each 700x700 grid. Your design has 32.86% in the flagged region, so you just need 0.14% more. Maybe moving macros would solve the problem.

@User The failure region between two SRAM over-lapping area .. Let me try with increasing the space between SRAM

@Dinesh A what were the changes you made in the SRAM spaces. I'm getting the same error at

FOM

too.

How many SRAM are used in your project ? I have increased the free space between SRAM to fix the issue.