Welcome to our site! EDAboard.com is an international Electronics 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.
Routing grids : These are the grids which are used by place and route tool to route the METAL layers. Place and route tools like MAGMA/silicon ensemble or VDIO does this because this will automatically satisfy the DRC rule.
Manufacturing grid : Its nothing but related to process. Your layout should on on manufacturing grid else it will cause a problem in process. This is because while chip fabrication there is limit because of aperture angle (while masking) hence all your chip dimension has to satisfy this.