What's difference between RF & normal process [CMOS] ?

Nowadays, no differences in most cases!

:)

Inductor and Varactor are added in RFCMOS.

I think in some cases RF devices are treated as independant devices also as they may have other design rules added for optimum finger width, guard rings etc.
The basic model would be the same though as for the normal device.

Brendan

RF device modeling is generally based on the digital device modeling. Some more parasitics may be added in, because at rf band, these parasitics' effect become obvious. For example, the TSMC018rf is based on the digital device, but resistors are added in the gate, drain, and source. Caps and diodes are also added. In order to improve the isolation, each rf mosfet may sit on its own well and have its own protection ring.

rf processes also manage to providing inductors on top metal.