| 초록 |
In this study, for the deposition of a SiNx encapsulation layer, a VHF (162 MHz) multi-tile push-pull-type plasma source was used and the characteristics of the N2 plasma and the SiNx thin film deposited with and without N2 added to NH3/SiH4 were investigated. We also compared the N2 plasma characteristics of the 162 MHz multi-tile push-pull plasma source with those of a lower frequency (60 MHz) CCP source. The 162 MHz push-pull-type plasma showed a lower electron temperature, a higher vibrational temperature, and a higher N2 dissociation compared to a lower frequency (60 MHz) CCP. When SiNx thin films were deposited with a mixture of NH3/SiH4 (with and without N2), a stoichiometric amorphous Si3N4 layer with very low Si-H bonding could be deposited for the gas mixture with N2, while a silicon-rich SiNx layer with high Si-H bonding could be deposited for the gas mixture without N2. When the optical transmittance and the WVTR were measured with the 300-nm thick SiNx deposited using the 162 MHz multi-tile push-pull plasma source with N2 added NH3/SiH4, high optical transmittance (＞ 90 %) and a low WVTR (1.18 x 10-4 g/m2·day) could be obtained at a substrate temperature of 100 ℃. In addition, the VHF multi-tile push-pull plasma source showed significantly less standing wave problem (non-uniformity for large area processing being far more significant for general CCP sources operated at VHF). Therefore, we believe that the VHF multi-tile push-pull plasma source can be applicable to deposit high quality thin films, including a thin film encapsulation layer on large area substrates. |
