Synchrotron radiation (SR) stimulated process, which has characteristics of high spatial resolution and low damage, is suitable for nano-processes. Si(111) surface after removal of native oxide by SR stimulated desorption was atomically flat with no damage. If the semiconductor surface is chemically modified and chemical bonds having a weak interaction with the substrate electronic states (a localized electronic state) are formed, for example, such as SiH2 and SiH3, they can be broken (etched) by the SR irradiations. Efficient site specific bone breaking, overwhelming the secondary electron effects, can be expected by a resonant excitations from a core electronic state to a dissociative valence electron state. The excitation energy and polarization tunability, which is unique characteristic of the SR process, will display its power in the nano-process applications which require the atom level control.