<@U039DRK4BFY> we are now seeing this in the final...
# chipignitec
Christopher Batten
06/17/2022, 10:24 PM@Nathan Pier we are now seeing this in the final tapeout check:
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STDOUT: {{Step Update}} Executing Check 4 of 5: Klayout Metal Minimum Clear Area Density on [caravel_22064452.oas]
STDERR: [ WARN ] MET Density Check Result: 'caravel_22064452.oas' has 1 DRC violations.n
Nathan Pier
06/17/2022, 10:30 PM@mkk @jeffdi I'm adding some of our team to this thread so they can provide technical support.
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Christopher Batten
06/17/2022, 10:30 PMok. we are trying a different version that has one more block ...
j
Jasper van Woudenberg
06/17/2022, 11:19 PMcould be similar issue I had before; check https://skywater-pdk.slack.com/archives/C02KCG2DZK7/p1636901382096400
j
jeffdi
06/18/2022, 2:02 AM
met densities are specified as clear area which must range from .4 to .65 for li, m1-4. met 5 must range from .24 to .55
jeffdi
06/18/2022, 2:07 AM
typically issues with being under on Li are due to using too many or all fill cells in a design vs decap. too high Li is usually due to using decap only. One solution is to use the modified EF decap size 12 cell which has a balanced Li and diffusion. This will address issues with Li density as well as FOM density (tap+diffusion). FOM density is specified using 700 um tiles stepped at 70um and must range between 0.38 and 0.57 (not clear area).
jeffdi
06/18/2022, 2:07 AM
if you are using OpenLane, you can adjust your config.tcl to use the modified decap cell.
jeffdi
06/18/2022, 2:09 AM
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set ::env(DECAP_CELL) "\
sky130_fd_sc_hd__decap_3 \
sky130_fd_sc_hd__decap_4 \
sky130_fd_sc_hd__decap_6 \
sky130_fd_sc_hd__decap_8 \
sky130_ef_sc_hd__decap_12"jeffdi
06/18/2022, 2:09 AM
@Jasper van Woudenberg @Christopher Batten ^^
c
Christopher Batten
06/18/2022, 2:42 AMwe just barely met the 0.4 limit when we submitted an updated version of our chip ... whew. For the future, can we put the DECAP_CELL command in our projects config.tcl? or do we need to do that in the PDK?
j
jeffdi
06/18/2022, 8:31 PM
you can include in the config.tcl
jeffdi
06/18/2022, 8:31 PM
thats great