diff --git a/sky130/magic/sky130.tech b/sky130/magic/sky130.tech
index 9f41101..1e2861d 100644
--- a/sky130/magic/sky130.tech
+++ b/sky130/magic/sky130.tech
@@ -251,12 +251,14 @@
   metal1 via1,m2contact,m2cut,m2c,via,v,v1
  -metal1 obsm1
  -metal1 padl
+ -metal1 m1fill
 
 # Metal 2
   metal2 metal2,m2,met2
  -metal2 rmetal2,rm2,rmet2
   metal2 via2,m3contact,m3cut,m3c,v2
  -metal2 obsm2
+ -metal2 m2fill
 
 # Metal 3
   metal3 metal3,m3,met3
@@ -264,6 +266,7 @@
  -metal3 obsm3
 #ifdef METAL5
   metal3 via3,v3
+ -metal3 m3fill
 
 #ifdef MIM
  -cap1 mimcap,mim,capm
@@ -275,6 +278,7 @@
  -metal4 rmetal4,rm4,rmet4
  -metal4 obsm4
   metal4 via4,v4
+ -metal4 m4fill
 
 #ifdef MIM
  -cap2 mimcap2,mim2,capm2
@@ -285,6 +289,7 @@
   metal5 metal5,m5,met5
  -metal5 rm5,rmetal5,rmet5
  -metal5 obsm5
+ -metal5 m5fill
 #endif (METAL5)
 
 #ifdef REDISTRIBUTION
@@ -518,14 +523,17 @@
   obslic    metal1	   metal2 via1arrow
 
   metal1    metal2
+  m1fill    metal2
   rm1       metal2         poly_resist_stripes
   obsm1     metal2
   m2c       metal2         metal3  via2arrow
   metal2    metal3
+  m2fill    metal3
   rm2       metal3         poly_resist_stripes
   obsm2     metal3
   m3c       metal3         metal4  via3alt
   metal3    metal4
+  m3fill    metal4
   rm3       metal4         poly_resist_stripes
   obsm3     metal4
 #ifdef METAL5
@@ -537,10 +545,12 @@
 #endif (MIM)
   via3      metal4         metal5  via4
   metal4    metal5
+  m4fill    metal5
   rm4       metal5         poly_resist_stripes
   obsm4     metal5
   via4      metal5         metal6  via5
   metal5    metal6
+  m5fill    metal6
   rm5       metal6         poly_resist_stripes
   obsm5     metal6
 #endif (METAL5)
@@ -635,12 +645,12 @@
   *nwell,*nsd,*mvnsd,dnwell *nwell,*nsd,*mvnsd,dnwell
   pwell,*psd,*mvpsd  pwell,*psd,*mvpsd
   *li,coreli	*li,coreli
-  *m1	*m1
-  *m2	*m2
-  *m3	*m3
+  *m1,m1fill	*m1,m1fill
+  *m2,m2fill	*m2,m2fill
+  *m3,m3fill	*m3,m3fill
 #ifdef METAL5
-  *m4	*m4
-  *m5	*m5
+  *m4,m4fill	*m4,m4fill
+  *m5,m5fill	*m5,m5fill
 #ifdef MIM
   *mimcap     *mimcap
   *mimcap2    *mimcap2
@@ -1031,7 +1041,7 @@
 #----------------------------------------------------------------
 # MET1
 #----------------------------------------------------------------
- layer MET1 	allm1
+ layer MET1 	allm1,m1fill
  	calma 	68 20
 
  layer MET1TXT
@@ -1056,7 +1066,7 @@
 #----------------------------------------------------------------
 # MET2
 #----------------------------------------------------------------
- layer MET2 	allm2
+ layer MET2 	allm2,m2fill
  	calma 	69 20
 
  layer MET2TXT
@@ -1081,7 +1091,7 @@
 #----------------------------------------------------------------
 # MET3
 #----------------------------------------------------------------
- layer MET3 	allm3
+ layer MET3 	allm3,m3fill
  	calma 	70 20
 
  layer MET3TXT
@@ -1110,7 +1120,7 @@
 #----------------------------------------------------------------
 # MET4
 #----------------------------------------------------------------
- layer MET4 	allm4
+ layer MET4 	allm4,m4fill
  	calma 	71 20
 
  layer MET4TXT
@@ -1138,7 +1148,7 @@
 #----------------------------------------------------------------
 # MET5
 #----------------------------------------------------------------
- layer MET5 	allm5
+ layer MET5 	allm5,m5fill
  	calma 	72 20
 
  layer MET5TXT
@@ -1467,26 +1477,356 @@
 style wafflefill
 #----------------------------------------------------------------
 # Style used by scripts for automatically generating fill layers
-# (under development)
 #----------------------------------------------------------------
  scalefactor 10  nanometers
  options calma-permissive-labels
  gridlimit 5
 
 #---------------------------------------------------
-# MET1 fill (under development)
+# FOM fill (under development)
 #---------------------------------------------------
- templayer      slots_m1
-        bbox    top
-        slots   33400 1150 1650 46000 13350 14650
- templayer      obstruct_m1 allm1,allpad,obsm1
-        grow    800
-        shrink  500
+ templayer      slots_fom_pass1
+	bbox	top
+        slots   0 4080 1320 0 4080 1320 1360 0
+ templayer      obstruct_fom_pass1 alldiff,allpoly,rpw
         grow    500
- layer met1fill slots_m1
-        and-not obstruct_m1
-        shrink  550
-        grow    550
+ templayer	fomfill_pass1 slots_fom_pass1
+        and-not obstruct_fom_pass1
+        shrink  2035
+        grow    2035
+
+ templayer      slots_fom_pass2
+	bbox	top
+        slots   0 2500 1320 0 2500 1320 1360 0
+ templayer      obstruct_fom_pass2 fomfill_pass1
+        grow    820
+	or	alldiff,allpoly,rpw
+        grow    500
+ templayer	fomfill_pass2 slots_fom_pass2
+        and-not obstruct_fom_pass2
+        shrink  1245
+        grow    1245
+
+ templayer      slots_fom_coarse
+	bbox	top
+        slots   0 1500 1320 0 1500 1320 1360 0
+ templayer      obstruct_fom_coarse fomfill_pass1,fomfill_pass2
+        grow    820
+	or	alldiff,allpoly,rpw
+        grow    500
+ templayer	fomfill_coarse slots_fom_coarse
+        and-not obstruct_fom_coarse
+        shrink  745
+        grow    745
+
+ templayer      slots_fom_fine
+	bbox	top
+        slots   0 500 400 0 500 400 160 0
+ templayer      obstruct_fom_fine fomfill_pass1,fomfill_pass2,fomfill_coarse
+	grow	820
+	or	alldiff,allpoly,rpw
+        grow    500
+ templayer	fomfill_fine slots_fom_fine
+        and-not obstruct_fom_fine
+        shrink  245
+        grow    245
+
+ layer	FOMMASK    fomfill_pass1 
+	or	fomfill_pass2
+	or	fomfill_coarse
+	or	fomfill_fine
+ 	calma 	23 0
+
+#---------------------------------------------------
+# POLY fill (under development)
+#---------------------------------------------------
+ templayer      slots_poly_pass1
+	bbox	top
+        slots   0 720 360 0 720 360 240 0
+ templayer      obstruct_poly_pass1 alldiff,allpoly,rpw
+        grow    1000
+ templayer	polyfill_pass1 slots_poly_pass1
+        and-not obstruct_poly_pass1
+        shrink  355
+        grow    355
+
+ templayer      slots_poly_coarse
+	bbox	top
+        slots   0 720 360 0 720 360 240 120
+ templayer      obstruct_poly_coarse alldiff,allpoly,rpw
+        grow    640
+	or	polyfill_pass1
+	grow	360
+ templayer	polyfill_coarse slots_poly_coarse
+        and-not obstruct_poly_coarse
+        shrink  355
+        grow    355
+
+ templayer      slots_poly_medium
+	bbox	top
+        slots   0 540 360 0 540 360 240 100
+ templayer      obstruct_poly_medium alldiff,allpoly,rpw
+        grow    650
+	or	polyfill_pass1,polyfill_coarse
+	grow	360
+ templayer	polyfill_medium slots_poly_medium
+        and-not obstruct_poly_medium
+        shrink  265
+        grow    265
+
+ templayer      slots_poly_fine
+	bbox	top
+        slots   0 480 360 0 480 360 240 200
+ templayer      obstruct_poly_fine alldiff,allpoly,rpw
+        grow    650
+	or	polyfill_pass1,polyfill_coarse,polyfill_medium
+	grow	360
+ templayer	polyfill_fine slots_poly_fine
+        and-not obstruct_poly_fine
+        shrink  235
+        grow    235
+
+ layer	POLYMASK    polyfill_pass1 
+	or	polyfill_coarse
+	or	polyfill_medium
+	or	polyfill_fine
+ 	calma 	28 0
+
+#---------------------------------------------------
+# MET1 fill
+#---------------------------------------------------
+ templayer      slots_m1_coarse
+        bbox    top
+        slots   0 2000 200 0 2000 200 700 0
+ templayer      obstruct_m1_coarse allm1,allpad,obsm1,m1fill,fillblock
+        grow    3000
+ templayer	met1fill_coarse slots_m1_coarse
+        and-not obstruct_m1_coarse
+        shrink  995
+        grow    995
+
+ templayer      slots_m1_medium
+        bbox    top
+        slots   0 1000 200 0 1000 200 700 0
+ templayer      obstruct_m1_medium allm1,allpad,obsm1,m1fill,fillblock
+        grow    2800
+	or	met1fill_coarse
+        grow    200
+ templayer	met1fill_medium slots_m1_medium
+        and-not obstruct_m1_medium
+        shrink  495
+        grow    495
+
+ templayer      slots_m1_fine
+        bbox    top
+        slots   0 580 200 0 580 200 700 0
+ templayer      obstruct_m1_fine allm1,allpad,obsm1,m1fill,fillblock
+        grow    300
+	or	met1fill_coarse,met1fill_medium
+        grow    200
+ templayer	met1fill_fine slots_m1_fine
+        and-not obstruct_m1_fine
+        shrink  285
+        grow    285
+
+ templayer      slots_m1_veryfine
+        bbox    top
+        slots   0 300 200 0 300 200 100 50
+ templayer      obstruct_m1_veryfine allm1,allpad,obsm1,m1fill,fillblock
+        grow    100
+	or	met1fill_coarse,met1fill_medium,met1fill_fine
+        grow    200
+ templayer	met1fill_veryfine slots_m1_veryfine
+        and-not obstruct_m1_veryfine
+        shrink  145
+        grow    145
+
+ layer	MET1MASK met1fill_coarse
+	or	met1fill_medium
+	or	met1fill_fine
+	or	met1fill_veryfine
+ 	calma 	36 0
+
+#---------------------------------------------------
+# MET2 fill
+#---------------------------------------------------
+ templayer      slots_m2_coarse
+        bbox    top
+        slots   0 2000 200 0 2000 200 700 350
+ templayer      obstruct_m2 allm2,allpad,obsm2,m2fill,fillblock
+        grow    3000
+ templayer	met2fill_coarse slots_m2_coarse
+        and-not obstruct_m2
+        shrink  995
+        grow    995
+
+ templayer      slots_m2_medium
+        bbox    top
+        slots   0 1000 200 0 1000 200 700 350
+ templayer      obstruct_m2_medium allm2,allpad,obsm2,m2fill,fillblock
+        grow    2800
+	or	met2fill_coarse
+        grow    200
+ templayer	met2fill_medium slots_m2_medium
+        and-not obstruct_m2_medium
+        shrink  495
+        grow    495
+
+ templayer      slots_m2_fine
+        bbox    top
+        slots   0 580 200 0 580 200 700 350
+ templayer      obstruct_m2_fine allm2,allpad,obsm2,m2fill,fillblock
+        grow    300
+	or	met2fill_coarse,met2fill_medium
+        grow    200
+ templayer	met2fill_fine slots_m2_fine
+        and-not obstruct_m2_fine
+        shrink  285
+        grow    285
+
+ templayer      slots_m2_veryfine
+        bbox    top
+        slots   0 300 200 0 300 200 100 100
+ templayer      obstruct_m2_veryfine allm2,allpad,obsm2,m2fill,fillblock
+        grow    100
+	or	met2fill_coarse,met2fill_medium,met2fill_fine
+        grow    200
+ templayer	met2fill_veryfine slots_m2_veryfine
+        and-not obstruct_m2_veryfine
+        shrink  145
+        grow    145
+
+ layer	MET2MASK met2fill_coarse
+	or met2fill_medium
+	or met2fill_fine
+	or met2fill_veryfine
+ 	calma 	41 0
+
+#---------------------------------------------------
+# MET3 fill
+#---------------------------------------------------
+ templayer      slots_m3_coarse
+        bbox    top
+        slots   0 2000 300 0 2000 300 700 700
+ templayer      obstruct_m3 allm3,allpad,obsm3,m3fill,fillblock
+        grow    3000
+ templayer	met3fill_coarse slots_m3_coarse
+        and-not obstruct_m3
+        shrink  995
+        grow    995
+
+ templayer      slots_m3_medium
+        bbox    top
+        slots   0 1000 300 0 1000 300 700 700
+ templayer      obstruct_m3_medium allm3,allpad,obsm3,m3fill,fillblock
+        grow    2700
+	or	met3fill_coarse
+        grow    300
+ templayer	met3fill_medium slots_m3_medium
+        and-not obstruct_m3_medium
+        shrink  495
+        grow    495
+
+ templayer      slots_m3_fine
+        bbox    top
+        slots   0 580 300 0 580 300 700 700
+ templayer      obstruct_m3_fine allm3,allpad,obsm3,m3fill,fillblock
+        grow    200
+	or	met3fill_coarse,met3fill_medium
+        grow    300
+ templayer	met3fill_fine slots_m3_fine
+        and-not obstruct_m3_fine
+        shrink  285
+        grow    285
+
+ templayer      slots_m3_veryfine
+        bbox    top
+        slots   0 400 300 0 400 300 150 200
+ templayer      obstruct_m3_veryfine allm3,allpad,obsm3,m3fill,fillblock
+	or	met3fill_coarse,met3fill_medium,met3fill_fine
+        grow    300
+ templayer	met3fill_veryfine slots_m3_veryfine
+        and-not obstruct_m3_veryfine
+        shrink  195
+        grow    195
+
+ layer	MET3MASK met3fill_coarse
+	or	met3fill_medium
+	or	met3fill_fine
+	or	met3fill_veryfine
+ 	calma 	34 0
+
+#ifdef METAL5
+#---------------------------------------------------
+# MET4 fill
+#---------------------------------------------------
+ templayer      slots_m4_coarse
+        bbox    top
+        slots   0 2000 300 0 2000 300 700 1050
+ templayer      obstruct_m4 allm4,allpad,obsm4,m4fill,fillblock
+        grow    3000
+ templayer	met4fill_coarse slots_m4_coarse
+        and-not obstruct_m4
+        shrink  995
+        grow    995
+
+ templayer      slots_m4_medium
+        bbox    top
+        slots   0 1000 300 0 1000 300 700 1050
+ templayer      obstruct_m4_medium allm4,allpad,obsm4,m4fill,fillblock
+        grow    2700
+	or	met4fill_coarse
+        grow    300
+ templayer	met4fill_medium slots_m4_medium
+        and-not obstruct_m4_medium
+        shrink  495
+        grow    495
+
+ templayer      slots_m4_fine
+        bbox    top
+        slots   0 580 300 0 580 300 700 1050
+ templayer      obstruct_m4_fine allm4,allpad,obsm4,m4fill,fillblock
+        grow    200
+	or	met4fill_coarse,met4fill_medium
+        grow    300
+ templayer	met4fill_fine slots_m4_fine
+        and-not obstruct_m4_fine
+        shrink  285
+        grow    285
+
+ templayer      slots_m4_veryfine
+        bbox    top
+        slots   0 400 300 0 400 300 150 300
+ templayer      obstruct_m4_veryfine allm4,allpad,obsm4,m4fill,fillblock
+	or	met4fill_coarse,met4fill_medium,met4fill_fine
+        grow    300
+ templayer	met4fill_veryfine slots_m4_veryfine
+        and-not obstruct_m4_veryfine
+        shrink  195
+        grow    195
+
+ layer	MET4MASK met4fill_coarse
+	or	met4fill_medium
+	or	met4fill_fine
+	or	met4fill_veryfine
+ 	calma 	51 0
+
+#---------------------------------------------------
+# MET5 fill
+#---------------------------------------------------
+ templayer      slots_m5
+        bbox    top
+        slots   0 3000 1600 0 3000 1600 1000 100
+ templayer      obstruct_m5 allm5,allpad,obsm5,m5fill,fillblock
+        grow    3000
+ templayer	met5fill_gen slots_m5
+        and-not obstruct_m5
+        shrink  1495
+        grow    1495
+
+ layer	MET5MASK met5fill_gen
+ 	calma 	59 0
+#endif (METAL5)
 
 end
 
@@ -2426,6 +2766,9 @@
  and MET1RES,MET1SHORT
  labels MET1RES,MET1SHORT
 
+ layer m1fill MET1FILL
+ labels MET1FILL
+
 #ifdef MIM
  layer mimcap MET3
  and CAPM
@@ -2471,6 +2814,9 @@
  and MET2RES,MET2SHORT
  labels MET2RES,MET2SHORT
 
+ layer m2fill MET2FILL
+ labels MET2FILL
+
  templayer m3cbase VIA2
  grow 40
 
@@ -2494,6 +2840,9 @@
  and MET3RES,MET3SHORT
  labels MET3RES,MET3SHORT
 
+ layer m3fill MET3FILL
+ labels MET3FILL
+
 #ifdef (METAL5)
 
  templayer via3base VIA3
@@ -2522,6 +2871,9 @@
  and MET4RES,MET4SHORT
  labels MET4RES,MET4SHORT
 
+ layer m4fill MET4FILL
+ labels MET4FILL
+
  layer m5 MET5,MET5TXT,MET5PIN
  and-not MET5RES,MET5SHORT
  labels MET5
@@ -2532,6 +2884,9 @@
  and MET5RES,MET5SHORT
  labels MET5RES,MET5SHORT
 
+ layer m5fill MET5FILL
+ labels MET5FILL
+
  templayer via4base VIA4
 #ifdef MIM
  and-not CAPM2
@@ -2890,6 +3245,14 @@
  calma MET5RES 72 13
 #endif
 
+ calma MET1FILL 68 28
+ calma MET2FILL 69 28
+ calma MET3FILL 70 28
+#ifdef METAL5
+ calma MET4FILL 71 28
+ calma MET5FILL 72 28
+#endif
+
  calma POLYSHORT 66 15
  calma LISHORT 67 15
  calma MET1SHORT 68 15
@@ -3294,6 +3657,7 @@
 
 
 #ifdef METAL5
+#undef METAL5
 #--------------------------------------------------
 # VIA3 - Requires METAL5 Module
 #--------------------------------------------------
@@ -3343,6 +3707,7 @@
  spacing allm5  allm5,obsm5 1600 touching_ok "Metal5 spacing < %d (Met5 2)"
  area allm5,obsm5 4000000 1600 "Metal5 minimum area < %a (Met5 4)"
 
+#define METAL5
 #endif (METAL5)
 
 #ifdef REDISTRIBUTION