diff --git a/cspdk/si220/cells.py b/cspdk/si220/cells.py
index ddd64fa..a5c2a1d 100644
--- a/cspdk/si220/cells.py
+++ b/cspdk/si220/cells.py
@@ -35,6 +35,7 @@ def straight(
 straight_so = partial(straight, cross_section="xs_so")
 straight_rc = partial(straight, cross_section="xs_rc")
 straight_ro = partial(straight, cross_section="xs_ro")
+straight_metal = partial(straight, cross_section="metal_routing")
 
 ################
 # Bends
@@ -98,6 +99,7 @@ def bend_euler(
 bend_so = partial(bend_euler, cross_section="xs_so")
 bend_rc = partial(bend_euler, cross_section="xs_rc")
 bend_ro = partial(bend_euler, cross_section="xs_ro")
+bend_metal = partial(bend_euler, cross_section="metal_routing")
 
 ################
 # Transitions
@@ -743,8 +745,6 @@ def heater() -> Component:
 def crossing_so() -> Component:
     """SOI220nm_1310nm_TE_STRIP_Waveguide_Crossing fixed cell."""
     c = gf.import_gds(PATH.gds / "SOI220nm_1310nm_TE_STRIP_Waveguide_Crossing.gds")
-    c.flatten()
-
     xc = 493.47
     dx = 8.47 / 2
     x = xc - dx
@@ -764,7 +764,6 @@ def crossing_so() -> Component:
 def crossing_rc() -> Component:
     """SOI220nm_1550nm_TE_RIB_Waveguide_Crossing fixed cell."""
     c = gf.import_gds(PATH.gds / "SOI220nm_1550nm_TE_RIB_Waveguide_Crossing.gds")
-    c.flatten()
     xc = 404.24
     dx = 9.24 / 2
     x = xc - dx
@@ -785,7 +784,6 @@ def crossing_rc() -> Component:
 def crossing_sc() -> Component:
     """SOI220nm_1550nm_TE_STRIP_Waveguide_Crossing fixed cell."""
     c = gf.import_gds(PATH.gds / "SOI220nm_1550nm_TE_STRIP_Waveguide_Crossing.gds")
-    c.flatten()
     xc = 494.24
     yc = 800
     dx = 9.24 / 2
@@ -836,5 +834,5 @@ def array(
 
 
 if __name__ == "__main__":
-    t = grating_coupler_rectangular_rc()
+    t = crossing_sc()
     t.show()
diff --git a/cspdk/si220/samples/circuit_simulations_sc_with_routing.py b/cspdk/si220/samples/circuit_simulations_sc_with_routing.py
index 1b40b43..9704eae 100644
--- a/cspdk/si220/samples/circuit_simulations_sc_with_routing.py
+++ b/cspdk/si220/samples/circuit_simulations_sc_with_routing.py
@@ -11,7 +11,7 @@
     mzi2 = c << cells.mzi_sc(delta_length=100)
     mzi2.dmove((200, 200))
     # route = tech.route_single_sc(c, mzi1.ports["o2"], mzi2.ports["o1"])
-    route = tech.route_bundle_sc(c, [mzi1.ports["o2"]], [mzi2.ports["o1"]])
+    route = tech.route_bundle(c, [mzi1.ports["o2"]], [mzi2.ports["o1"]])
     c.add_port(name="o1", port=mzi1.ports["o1"])
     c.add_port(name="o2", port=mzi2.ports["o2"])
     c.show()
diff --git a/cspdk/si220/tech.py b/cspdk/si220/tech.py
index e08b6b3..c876a70 100644
--- a/cspdk/si220/tech.py
+++ b/cspdk/si220/tech.py
@@ -175,25 +175,21 @@ def xs_sc_heater_metal(width=Tech.width_sc, **kwargs) -> gf.CrossSection:
     return xs
 
 
-def metal_routing(width=10.0, **kwargs) -> gf.CrossSection:
-    kwargs["layer"] = kwargs.get("layer", LAYER.PAD)
-    kwargs["port_names"] = kwargs.get(
-        "port_names", gf.cross_section.port_names_electrical
-    )
-    kwargs["port_types"] = kwargs.get(
-        "port_types", gf.cross_section.port_types_electrical
-    )
-    kwargs["radius"] = kwargs.get("radius", 0)
-    kwargs["radius_min"] = kwargs.get("radius_min", kwargs["radius"])
-    xs = gf.cross_section.strip_heater_metal(width=width, **kwargs)
+def metal_routing(
+    width=10.0,
+    radius: float = 10,
+) -> gf.CrossSection:
+    xs = gf.cross_section.metal1(width=width, radius=radius, layer=LAYER.PAD)
     if xs.name in DEFAULT_CROSS_SECTION_NAMES:
         xs._name = DEFAULT_CROSS_SECTION_NAMES[xs.name]
     return xs
 
 
-def heater_metal(width=4.0, **kwargs) -> gf.CrossSection:
-    kwargs["layer"] = kwargs.get("layer", LAYER.HEATER)
-    xs = metal_routing(width=width, **kwargs).copy()
+def heater_metal(
+    width=4.0,
+    radius: float = 10,
+) -> gf.CrossSection:
+    xs = gf.cross_section.metal1(width=width, radius=radius, layer=LAYER.HEATER)
     if xs.name in DEFAULT_CROSS_SECTION_NAMES:
         xs._name = DEFAULT_CROSS_SECTION_NAMES[xs.name]
     return xs
@@ -269,7 +265,7 @@ def route_bundle(
     cross_section: CrossSectionSpec = "xs_sc",
     straight: ComponentSpec = "straight_sc",
     bend: ComponentSpec = "bend_sc",
-    taper: ComponentSpec = "taper_sc",
+    taper: ComponentSpec | None = "taper_sc",
 ) -> list[OpticalManhattanRoute]:
     return gf.routing.route_bundle(
         component=component,
@@ -353,6 +349,20 @@ def route_bundle(
         taper="taper_ro",
         cross_section="xs_ro",
     ),
+    route_bundle_metal=partial(
+        route_bundle,
+        straight="straight_metal",
+        bend="bend_metal",
+        taper=None,
+        cross_section="metal_routing",
+    ),
+    route_bundle_metal_corner=partial(
+        route_bundle,
+        straight="straight_metal",
+        bend="wire_corner",
+        taper=None,
+        cross_section="metal_routing",
+    ),
 )
 
 if __name__ == "__main__":
@@ -373,6 +383,8 @@ def route_bundle(
         connectivity=connectivity,
     )
     t.write_tech(tech_dir=PATH.klayout)
-    print(DEFAULT_CROSS_SECTION_NAMES)
-    print(xs_sc() is xs_sc())
-    print(xs_sc().name, xs_sc().name)
+    # print(DEFAULT_CROSS_SECTION_NAMES)
+    # print(xs_sc() is xs_sc())
+    # print(xs_sc().name, xs_sc().name)
+    # c = gf.c.bend_euler(cross_section="metal_routing")
+    # c.pprint_ports()
diff --git a/pyproject.toml b/pyproject.toml
index 4ff4140..bc1925f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,10 +11,11 @@ authors = [
 classifiers = [
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
+  "Programming Language :: Python :: 3.12",
   "Operating System :: OS Independent"
 ]
 dependencies = [
-  "gdsfactory~=8.5.0",
+  "gdsfactory~=8.5.3",
   "gplugins[sax]>=1,<2"
 ]
 description = "CornerStone PDK"
diff --git a/tests/gds_ref_si220/array.gds b/tests/gds_ref_si220/array.gds
index 1f95853..df24132 100644
Binary files a/tests/gds_ref_si220/array.gds and b/tests/gds_ref_si220/array.gds differ
diff --git a/tests/gds_ref_si220/bend_metal.gds b/tests/gds_ref_si220/bend_metal.gds
new file mode 100644
index 0000000..d433446
Binary files /dev/null and b/tests/gds_ref_si220/bend_metal.gds differ
diff --git a/tests/gds_ref_si220/grating_coupler_array.oas b/tests/gds_ref_si220/grating_coupler_array.oas
deleted file mode 100644
index 6f2cbe6..0000000
Binary files a/tests/gds_ref_si220/grating_coupler_array.oas and /dev/null differ
diff --git a/tests/gds_ref_si220/straight_metal.gds b/tests/gds_ref_si220/straight_metal.gds
new file mode 100644
index 0000000..eeb5cce
Binary files /dev/null and b/tests/gds_ref_si220/straight_metal.gds differ
diff --git a/tests/gds_ref_si220/straight_sc.oas b/tests/gds_ref_si220/straight_sc.oas
deleted file mode 100644
index 9d44493..0000000
Binary files a/tests/gds_ref_si220/straight_sc.oas and /dev/null differ
diff --git a/tests/gds_ref_si220/taper_sc.oas b/tests/gds_ref_si220/taper_sc.oas
deleted file mode 100644
index 68cac4c..0000000
Binary files a/tests/gds_ref_si220/taper_sc.oas and /dev/null differ
diff --git a/tests/gds_ref_si500/mmi1x2.gds b/tests/gds_ref_si500/mmi1x2.gds
index c055cdb..f7dfe6e 100644
Binary files a/tests/gds_ref_si500/mmi1x2.gds and b/tests/gds_ref_si500/mmi1x2.gds differ
diff --git a/tests/gds_ref_si500/mmi1x2_rc.gds b/tests/gds_ref_si500/mmi1x2_rc.gds
index c055cdb..f7dfe6e 100644
Binary files a/tests/gds_ref_si500/mmi1x2_rc.gds and b/tests/gds_ref_si500/mmi1x2_rc.gds differ
diff --git a/tests/gds_ref_si500/mmi1x2_ro.gds b/tests/gds_ref_si500/mmi1x2_ro.gds
index f802265..1792d54 100644
Binary files a/tests/gds_ref_si500/mmi1x2_ro.gds and b/tests/gds_ref_si500/mmi1x2_ro.gds differ
diff --git a/tests/gds_ref_si500/mmi2x2.gds b/tests/gds_ref_si500/mmi2x2.gds
index 80a928b..db6dd2a 100644
Binary files a/tests/gds_ref_si500/mmi2x2.gds and b/tests/gds_ref_si500/mmi2x2.gds differ
diff --git a/tests/gds_ref_si500/mmi2x2_rc.gds b/tests/gds_ref_si500/mmi2x2_rc.gds
index 80a928b..db6dd2a 100644
Binary files a/tests/gds_ref_si500/mmi2x2_rc.gds and b/tests/gds_ref_si500/mmi2x2_rc.gds differ
diff --git a/tests/gds_ref_si500/mmi2x2_ro.gds b/tests/gds_ref_si500/mmi2x2_ro.gds
index 1495089..7d8d487 100644
Binary files a/tests/gds_ref_si500/mmi2x2_ro.gds and b/tests/gds_ref_si500/mmi2x2_ro.gds differ
diff --git a/tests/gds_ref_si500/mzi.gds b/tests/gds_ref_si500/mzi.gds
index b25f0d3..ab0a411 100644
Binary files a/tests/gds_ref_si500/mzi.gds and b/tests/gds_ref_si500/mzi.gds differ
diff --git a/tests/gds_ref_si500/mzi_rc.gds b/tests/gds_ref_si500/mzi_rc.gds
index b25f0d3..ab0a411 100644
Binary files a/tests/gds_ref_si500/mzi_rc.gds and b/tests/gds_ref_si500/mzi_rc.gds differ
diff --git a/tests/gds_ref_si500/mzi_ro.gds b/tests/gds_ref_si500/mzi_ro.gds
index 6a74987..bc06da5 100644
Binary files a/tests/gds_ref_si500/mzi_ro.gds and b/tests/gds_ref_si500/mzi_ro.gds differ
diff --git a/tests/gds_ref_si500/taper.gds b/tests/gds_ref_si500/taper.gds
index 847cb80..91bc773 100644
Binary files a/tests/gds_ref_si500/taper.gds and b/tests/gds_ref_si500/taper.gds differ
diff --git a/tests/gds_ref_si500/taper_rc.gds b/tests/gds_ref_si500/taper_rc.gds
index 847cb80..91bc773 100644
Binary files a/tests/gds_ref_si500/taper_rc.gds and b/tests/gds_ref_si500/taper_rc.gds differ
diff --git a/tests/gds_ref_si500/taper_ro.gds b/tests/gds_ref_si500/taper_ro.gds
index fea988d..a04c58e 100644
Binary files a/tests/gds_ref_si500/taper_ro.gds and b/tests/gds_ref_si500/taper_ro.gds differ
diff --git a/tests/test_netlists_si220.py b/tests/test_netlists_si220.py
index 0ba2811..356a178 100644
--- a/tests/test_netlists_si220.py
+++ b/tests/test_netlists_si220.py
@@ -11,7 +11,7 @@
 
 
 @pytest.fixture(autouse=True)
-def activate_pdk():
+def activate_pdk() -> None:
     PDK.activate()
     gf.clear_cache()
 
diff --git a/tests/test_netlists_si220/test_netlists_bend_metal_.yml b/tests/test_netlists_si220/test_netlists_bend_metal_.yml
new file mode 100644
index 0000000..3534c43
--- /dev/null
+++ b/tests/test_netlists_si220/test_netlists_bend_metal_.yml
@@ -0,0 +1,5 @@
+instances: {}
+name: bend_euler_RNone_A90_P0_3e16ea58
+nets: []
+placements: {}
+ports: {}
diff --git a/tests/test_netlists_si220/test_netlists_grating_coupler_array_.yml b/tests/test_netlists_si220/test_netlists_grating_coupler_array_.yml
index c2c187e..f21b195 100644
--- a/tests/test_netlists_si220/test_netlists_grating_coupler_array_.yml
+++ b/tests/test_netlists_si220/test_netlists_grating_coupler_array_.yml
@@ -71,7 +71,7 @@ instances:
       n_periods: 60
       period: 0.63
       wavelength: 1.55
-name: grating_coupler_array_P_72908cae
+name: grating_coupler_array_P_672610bf
 nets: []
 placements:
   grating_coupler_rectang_ed54bb3e_-190500_-193900:
diff --git a/tests/test_netlists_si220/test_netlists_straight_metal_.yml b/tests/test_netlists_si220/test_netlists_straight_metal_.yml
new file mode 100644
index 0000000..c16e9ce
--- /dev/null
+++ b/tests/test_netlists_si220/test_netlists_straight_metal_.yml
@@ -0,0 +1,5 @@
+instances: {}
+name: straight_L10_WNone_CSme_3feaad2d
+nets: []
+placements: {}
+ports: {}
diff --git a/tests/test_netlists_si500.py b/tests/test_netlists_si500.py
index 07de58e..38a010f 100644
--- a/tests/test_netlists_si500.py
+++ b/tests/test_netlists_si500.py
@@ -10,8 +10,7 @@
 
 
 @pytest.fixture(autouse=True)
-def activate_pdk():
-    gf.clear_cache()
+def activate_pdk() -> None:
     PDK.activate()
     gf.clear_cache()
 
diff --git a/tests/test_netlists_sin300.py b/tests/test_netlists_sin300.py
index 45868d4..784e022 100644
--- a/tests/test_netlists_sin300.py
+++ b/tests/test_netlists_sin300.py
@@ -10,7 +10,7 @@
 
 
 @pytest.fixture(autouse=True)
-def activate_pdk():
+def activate_pdk() -> None:
     PDK.activate()
     gf.clear_cache()
 
@@ -34,13 +34,13 @@ def _get_instance(inst):
 
 
 def instances_without_info(net):
-    ret = {}
-    for k, v in net.get("instances", {}).items():
-        ret[k] = {
+    return {
+        k: {
             "component": v.get("component", ""),
             "settings": v.get("settings", {}),
         }
-    return ret
+        for k, v in net.get("instances", {}).items()
+    }
 
 
 @pytest.mark.parametrize("name", cells)
diff --git a/tests/test_pdk_si220.py b/tests/test_pdk_si220.py
index fc376b0..332b00f 100644
--- a/tests/test_pdk_si220.py
+++ b/tests/test_pdk_si220.py
@@ -9,7 +9,7 @@
 
 
 @pytest.fixture(autouse=True)
-def activate_pdk():
+def activate_pdk() -> None:
     PDK.activate()
     gf.clear_cache()
 
diff --git a/tests/test_pdk_si220/test_settings_bend_metal_.yml b/tests/test_pdk_si220/test_settings_bend_metal_.yml
new file mode 100644
index 0000000..6fba775
--- /dev/null
+++ b/tests/test_pdk_si220/test_settings_bend_metal_.yml
@@ -0,0 +1,16 @@
+info:
+  dy: 10
+  length: 16.637
+  min_bend_radius: 7.061
+  radius: 10
+  route_info_length: 16.637
+  route_info_metal_routing_length: 16.637
+  route_info_min_bend_radius: 7.061
+  route_info_n_bend_90: 1
+  route_info_type: metal_routing
+  route_info_weight: 16.637
+name: bend_euler_RNone_A90_P0_3e16ea58
+settings:
+  angle: 90
+  cross_section: metal_routing
+  p: 0.5
diff --git a/tests/test_pdk_si220/test_settings_grating_coupler_array_.yml b/tests/test_pdk_si220/test_settings_grating_coupler_array_.yml
index 40299e4..fa9695a 100644
--- a/tests/test_pdk_si220/test_settings_grating_coupler_array_.yml
+++ b/tests/test_pdk_si220/test_settings_grating_coupler_array_.yml
@@ -1,5 +1,5 @@
 info: {}
-name: grating_coupler_array_P_72908cae
+name: grating_coupler_array_P_672610bf
 settings:
   centered: true
   cross_section: xs_sc
diff --git a/tests/test_pdk_si220/test_settings_straight_metal_.yml b/tests/test_pdk_si220/test_settings_straight_metal_.yml
new file mode 100644
index 0000000..6009473
--- /dev/null
+++ b/tests/test_pdk_si220/test_settings_straight_metal_.yml
@@ -0,0 +1,11 @@
+info:
+  length: 10
+  route_info_length: 10
+  route_info_metal_routing_length: 10
+  route_info_type: metal_routing
+  route_info_weight: 10
+  width: 10
+name: straight_L10_WNone_CSme_3feaad2d
+settings:
+  cross_section: metal_routing
+  length: 10
diff --git a/tests/test_pdk_si500.py b/tests/test_pdk_si500.py
index da4f67c..efc00fb 100644
--- a/tests/test_pdk_si500.py
+++ b/tests/test_pdk_si500.py
@@ -9,7 +9,7 @@
 
 
 @pytest.fixture(autouse=True)
-def activate_pdk():
+def activate_pdk() -> None:
     PDK.activate()
     gf.clear_cache()
 
diff --git a/tests/test_pdk_sin300.py b/tests/test_pdk_sin300.py
index ed3032f..7e4571f 100644
--- a/tests/test_pdk_sin300.py
+++ b/tests/test_pdk_sin300.py
@@ -9,7 +9,7 @@
 
 
 @pytest.fixture(autouse=True)
-def activate_pdk():
+def activate_pdk() -> None:
     PDK.activate()
     gf.clear_cache()