Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
As you know, foundry use 2 masks successively to make one layer on chip, so each metal will have 'perfect direction', same masks with large space compared with different masks with small space, of course some
forbidden space and width.
For more details, you can check foundry design rules.