the present invention is directed , in general , to an improved material and method of planarizing a surface on a semiconductor wafer and , more specifically , to a method of altering the properties of polymers , preferably thermoplastic foam polymers , used in polishing applications . the chemical and mechanical properties thermoplastic foam substrates can be transformed by inorganic , inorganic - organic , and or organic - organic grafting techniques , such that the polymer foam is endowed with new set of properties that more desirable and suitable for polishing .