#1549 PDN can place vias in ways that break DRC Issue created by gregdavill Description I've included the SRAM IP block from GF180 in a design (gf180mcu_fd_ip_sram__sram256x8m8wm1). When running DRC on the hardened design it failed with 100x

V3.2a : min. via3 spacing : 0.26µm

errors. Looking at the GDS I see that the PDN has routed a vertical strap directly over multiple overlapping Metal 3 geometries in the IP block. And in 2 places the via grid it tried to place was offset at 1/2 so the vias did not overlap. But they are too close according to DRC. The design is here:

serv_0

this commit is the one that shows the issue: https://github.com/gregdavill/gf180-mpw0-serv/blob/91ddd78fc81e904b4ff1f63cd234433312043c27/gds/serv_0.gds Expected Behavior PDN places vias according to DRC. Environment report

Kernel: Linux v5.19.0-23-generic
Distribution: ubuntu 22.10
Python: v3.10.7 (OK)
Container Engine: docker v20.10.17 (OK)
OpenLane Git Version: 235fa7a4a2872e779588919c58fc4fa32568e075
pip: INSTALLED
python-venv: INSTALLED
---
PDK Version Verification Status: OK
---
Git Log (Last 3 Commits)

235fa7a 2022-11-28T17:17:32+02:00 [BOT] Update PDK (#1516) - Openlane Bot -  (grafted, HEAD, tag: 2022.11.29)
---
Git Remotes

origin	<https://github.com/The-OpenROAD-Project/OpenLane> (fetch)
origin	<https://github.com/The-OpenROAD-Project/OpenLane> (push)

Reproduction material gf180-mpw0-serv-91ddd78fc81e904b4ff1f63cd234433312043c27.zip Build instructions:

git submodule update --init
make serv_0

Relevant log output ``` [STEP 7] [INFO]: Generating PDN (log: ../home/runner/work/gf180-mpw0-serv/gf180-mpw0-serv/openlane/serv_0/runs/22_12_04_22_51/logs/floorplan/7-pdn.log)... [INFO]: Executing openroad with Tcl script 'scripts/openroad/pdn.tcl'... OpenROAD 7c85c140308f01b73f57ea1117f3e43f39abd437 This program is licensed under the BSD-3 license. See the LICENSE file for details. Components of this program may be licensed under more restrictive licenses which must be honored. [INFO PDN-0001] Inserting grid: stdcell_grid [INFO PDN-0001] Inserting grid: macro - u_cpu.rf_ram.RAM0 [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (82.2400, 411.8850) - (83.0400, 416.8900) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (127.2400, 80.0000) - (128.2450, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (127.2400, 232.0150) - (128.2500, 353.1100) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (127.2400, 382.3550) - (128.5000, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (217.2400, 80.0000) - (218.2450, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (217.2400, 232.0150) - (218.2500, 353.1100) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (217.2400, 382.3550) - (218.5000, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (262.2400, 213.8600) - (263.4500, 371.7550) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (262.2400, 369.5400) - (263.4500, 371.7550) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (278.7100, 89.7700) - (278.8400, 210.3500) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (278.7100, 373.9250) - (278.8400, 503.5850) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (278.8000, 80.0000) - (278.8400, 210.3500) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (278.8000, 373.9250) - (278.8400, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (307.2400, 216.9350) - (308.8400, 219.1300) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (307.2400, 360.3900) - (308.8400, 368.3850) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (322.2400, 387.5100) - (323.8400, 498.8150) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (337.8900, 200.5550) - (338.8400, 219.1400) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (337.8950, 80.0000) - (338.8400, 201.2500) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 80.0000) - (353.5750, 216.0700) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 200.2350) - (353.8400, 216.0700) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 331.1400) - (353.5750, 511.8600) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 331.1400) - (353.8400, 372.1050) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 387.4000) - (353.5750, 511.8600) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 389.0350) - (353.5750, 442.1450) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 443.0350) - (353.5750, 511.8600) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (352.2400, 495.8450) - (353.5750, 501.1050) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (367.2400, 80.0000) - (368.8400, 95.0550) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (367.2400, 91.1450) - (368.8400, 201.2500) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (367.2400, 91.2450) - (368.8400, 201.2500) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (367.2400, 200.2350) - (368.8400, 219.1400) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (367.2400, 366.4750) - (368.8400, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (367.2400, 389.1250) - (368.8400, 511.8600) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (368.7800, 289.2850) - (368.8400, 337.1500) on vss [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (382.2400, 220.8900) - (383.8400, 223.6450) on vdd [WARNING PDN-0110] No via inserted between Metal3 and Metal4 at (382.6200, 227.6850) - (383.8400, 253.1100) on vdd [WARNING PSM-0016] Voltage pad location (VSRC) file not specified, defaulting pad location to checkerboard pattern on core area. [WARNING PSM-0017] X direction bump pitch is not specified, defaulting to 140um. [WARNING PSM-0018] Y direction bump pitch is not specified, defaulting to 140um. [WARNING PSM-0019] Voltage on net vdd is not explicitly set. [WARNING PSM-0022] Using voltage 0.000V for VDD network. [WARNING PSM-0065] VSRC location not specified, using default checkerboard pattern with one VDD every size bumps in x-direction and one in two bumps in the y-direction [INFO PSM-0076] Setting metal node density to be standard cell height times 5. [WARNING PSM-0030] VSRC location at (420.000um, 229.880um) and size 10.000um, is not located on an existing power stripe node. Moving to closest node at (413.040um, 230.210um). [INFO PSM-0031] Number of PDN nodes on net vdd = 6074. [INFO PSM-0064] Number of voltage sources = 3. [INFO PSM-0040] All PDN stripes on net vdd are connected. [WARNING PSM-0016] Voltage pad location (VSRC) file not specified, defaulting pad location to checkerboard pattern on core area. [WARNING PSM-0017] X direction bump pitch is not specified, defaulting to 140um. [WARNING PSM-0018] Y direction bump pitch is not specified, defaulting to 140um. [WARNING PSM-0019] Voltage on net vss is not explicitly set. [WARNING PSM-0021] Using voltage 0.000V for ground network. [WARNING PSM-0065] VSRC location not specified, using de… The-OpenROAD-Project/OpenLane

#1549 PDN can place vias in ways that break DRC Issue closed as completed by maliberty The-OpenROAD-Project/OpenLane