Physical and chemical changes of polystyrene nanospheres irradiated with laser

It has been reported that polymer resist such as PMMA (Polymethyl methacrylate) which is a well known and commonly used polymer resist for fabrication of electronic devices can show zwitter characteristic due to over exposure of electron beam [1]. They tend to change their molecular structure to either become negative or positive resist corresponded to irradiation doses. These characteristic was due to crosslinking and scissors of the PMMA molecular structures, but till now the understanding of crosslinking and scissors of the polymer resist molecular structure due to electron beam exposure were still unknown to researchers [2–5].