Suboxide/subnitride formation on Ta masks during magnetic material etching by reactive plasmas

摘要: Etching characteristics of tantalum (Ta) masks used in magnetoresistive random-access memory etching processes by carbon monoxide and ammonium (CO/NH3) or methanol (CH3OH) plasmas have been examined mass-selected ion beam experiments with in-situ surface analyses. It has suggested earlier studies that magnetic materials, i.e., Fe, Ni, Co, their alloys, such is mostly due to physical sputtering etch selectivity the process arises from resistance (i.e., low-sputtering yield) hard mask materials as Ta. In this study, it shown that, during Ta energetic CO+ N+ ions, suboxides subnitrides are formed on surface, which reduces apparent yield also ions a strong dependence angle incidence, suggests correlation between oxidation states suboxide subnitride; higher state Ta, lower yield. These data account for observed CO/NH3 CH3OH plasmas.