Tweaked the fill pattern slots operators to ensure a maximum fill density on a clear area that is less than the specified DRC maximum. For M5, increased the fill shape size to exceed the specified DRC minimum---this rule may need further tweaking.
diff --git a/sky130/magic/sky130.tech b/sky130/magic/sky130.tech index 93a8df9..bf67343 100644 --- a/sky130/magic/sky130.tech +++ b/sky130/magic/sky130.tech
@@ -1890,7 +1890,8 @@ templayer obstruct_li_coarse allli,allpad,obsli,lifill,fillblock,fillblock4 grow 3000 templayer lifill_coarse topbox - slots 0 2000 200 0 2000 200 700 0 + # slots 0 2000 200 0 2000 200 700 0 + slots 0 2000 350 0 2000 350 700 0 and-not obstruct_li_coarse and topbox shrink 995 @@ -1930,7 +1931,8 @@ templayer obstruct_m1_coarse allm1,allpad,obsm1,m1fill,fillblock,fillblock4 grow 3000 templayer met1fill_coarse topbox - slots 0 2000 200 0 2000 200 700 0 + # slots 0 2000 200 0 2000 200 700 0 + slots 0 2000 350 0 2000 350 700 0 and-not obstruct_m1_coarse and topbox shrink 995 @@ -1981,7 +1983,8 @@ templayer obstruct_m2 allm2,allpad,obsm2,m2fill,fillblock,fillblock4 grow 3000 templayer met2fill_coarse topbox - slots 0 2000 200 0 2000 200 700 350 + # slots 0 2000 200 0 2000 200 700 350 + slots 0 2000 350 0 2000 350 700 350 and-not obstruct_m2 and topbox shrink 995 @@ -2032,7 +2035,8 @@ templayer obstruct_m3 allm3,allpad,obsm3,m3fill,fillblock,fillblock4 grow 3000 templayer met3fill_coarse topbox - slots 0 2000 300 0 2000 300 700 700 + # slots 0 2000 300 0 2000 300 700 700 + slots 0 2000 350 0 2000 350 700 700 and-not obstruct_m3 and topbox shrink 995 @@ -2085,7 +2089,8 @@ templayer obstruct_m4 allm4,allpad,obsm4,m4fill,fillblock,fillblock4 grow 3000 templayer met4fill_coarse topbox - slots 0 2000 300 0 2000 300 700 1050 + # slots 0 2000 300 0 2000 300 700 1050 + slots 0 2000 350 0 2000 350 700 1050 and-not obstruct_m4 and topbox shrink 995 @@ -2137,7 +2142,8 @@ templayer obstruct_m5 allm5,allpad,obsm5,m5fill,fillblock grow 3000 templayer met5fill_gen topbox - slots 0 3000 1600 0 3000 1600 1000 100 + # slots 0 3000 1600 0 3000 1600 1000 100 + slots 0 5000 1600 0 5000 1600 1000 100 and-not obstruct_m5 and topbox shrink 1495