By using DBD-type atmospheric pressure plasmas and a dopamine solution mist formed by a piezoelectric module, the possibility of depositing functional polymer films showing the physical and chemical characteristics of polydopamine without breaking the functional group of the dopamine has been investigated for different plasma voltages. The higher DBD voltages up to 3.0 kV decreased the functional groups such as catechol and amine (N/C ratio) relative to dopamine in the deposited polymer by increasing the dissociation of dopamine into atoms and small molecules due to higher electron energies. In contrast, the lower DBD voltages up to 1.5 kV increased the functional group and N/C ratio of dopamine in the deposited polymer by keeping the molecular structures of the dopamine due to lower electron energies. Therefore, the polymer deposited at the lower DBD voltages showed lower contact angles and higher metal absorption properties which are some of the surface modification characteristics of polydopamine. When the metal absorption properties of the polydopamine-like film deposited using the atmospheric pressure plasma of a low DBD voltage with a dopamine solution mist were compared with other metal absorbers for Cu, As, and Cr, the polydopamine-like film exhibited superior metal absorption properties. It is believed that this atmospheric pressure plasma process can be also applied to the plasma polymerization of other monomers without breaking the functional groups of the monomers.

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Selective isotropic cyclic dry etching of silicon oxide (SiO2) was investigated using a three‐step cyclic process composed of hydrogen fluoride (HF) adsorption by NF3/H2 remote plasma and reaction with NH3 gas flow to form ammonium fluorosilicate ((NH4)2SiF6), and desorption by heating. The variation of the ratio of NF3:H2 (2:1 to 1:3) and adsorption time (10–180 s) showed the highest etch selectivity of SiO2 over Si3N4 at 1:2 ratio of NF3:H2 and with the adsorption time of 20 s. The etch selectivity higher than 40 was observed with 20 s of adsorption time with a 1:2 ratio of NF3:H2 remote plasma and the total etch depth was linearly increased with the increase of cycles with the SiO2 EPC of ~7.5 nm/cycle.

Magnetic tunneling junction (MTJ) materials such as CoFeB, Co, Pt, MgO, and the hard mask material such as W and TiN were etched with a reactive ion beam etching (RIBE) system using H2/NH3. By using gas mixtures of H2 and NH3, especially with the H2/NH3( 2:1) ratio, higher etch rates of MTJ related materials and higher etch selectivities over mask materials (>30) could be observed compared to those etching using pure H2( no etching) and NH3. In addition, no significant chemical and physical damages were observed on etched magnetic materials surfaces and, for CoPt and MTJ nanoscale patterns etched by the H2/NH3( 2:1) ion beam, highly anisotropic etch profiles >83° with no sidewall redeposition could be observed. The higher etch rates of magnetic materials such as CoFeB by the H2/NH3( 2:1) ion beam compared to those by H2 ion beam or NH3 ion beam are believed to be related to the formation of volatile metal hydrides (MH, M = Co, Fe, etc) through the reduction of M-NHx( x = 1 ∼ 3) formed in the CoFeB surface by the exposure to NH3 ion beam. It is believed that the H2/NH3 RIBE is a suitable technique in the etching of MTJ materials for the next generation nanoscale spin transfer torque magnetic random access memory (STT-MRAM) devices.