Gyanesh Jha
After synthesis your gate level netlist is ready which can be used for the physical design flow which is basically a technology and foundary dependent flow, the steps include floorplanning with the placement of macros and and then placement where you place the actual standard cells of your design,
After which you perform two levels of routing the global routing and the detailed routing.
After which your layout is ready.
Each of the stage has its own constraints.
Static timing analysis is basically a timing analysis tool measuring your timing related issues like slack worst negative slack total negative slack etc. And is performed at almost every step of physical design.