Etching enhancement in through‐implanted SiO2has been characterized by nuclear‐deposited energy independently of implant conditions. An empirical expression has been proposed to describe the etching rate for any implantation. The enhanced etching has been related to the Si‐O vibrational frequency shift. Etching enhancement has been found to reflect the structural change in SiO2, and to be a good measure of degradation. The structural change of SiO2stops and the etching rate reaches a maximum for an ion dose corresponding to nuclear‐deposited energy larger than 3.4×1023eV/cm3. This energy is equal to the total SiO bonding energy (3.8 eV) in a unit volume of SiO2.