Interactions of nitrogen plasmas with polymer surfaces were investigated using hard x-ray photoelectron spectroscopy (HXPES) to complete depth analyses of the chemical bonding states in the nano-surface layer of polymethylmethacrylate (PMMA) films via. The PMMA films were exposed to the nitrogen plasmas sustained via inductive coupling of radio-frequency (RF) power with multiple low-inductance antenna (LIA) modules. The etching rate of the PMMA films was 38 nm/min. The surface roughness of PMMA increased from 0.3 nm to 0.7 nm with increased exposure time. The HXPES was carried out for non-destructive depth analysis of chemical bonding states in the nano-surface layer of PMMA films. The HXPES results indicated that nitrogen functionalities were formed in the shallower regions up to about 27 nm from the surface without showing significant degradation of the molecular structure of PMMA due to nitrogen plasma exposure.