It is the process of creating physical connections to all clock and signal pins. Moreover, this stage is meant for signal routing.
Routing deals with 4 steps.
1. Global Routing
2. Track Assignment
3. Detailed Routing
4. Search n Repair
Global Routing: Assigns layers required for connectivity and finds the nearest path between the cells of the design by dividing the core area into small cells called "G-cells".
Track Assignment: Assigns tracks required for the connections.
Detailed Routing: Nets are to be laid down on the assigned tracks.
Search n Repair: Searches for any physical DRC violations and repairs it.
Among power routing, clock routing and signal routing, the sequence to be followed is:
1. power routing(Power planning)
2. clock routing(CTS)
3. signal routing(Routing)