| AVS 64th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology Division | Thursday Sessions |
| Session NS-ThP |
| Session: | Nanometer-scale Science and Technology Poster Session |
| Presenter: | JaeYong Lee, Inha University, Republic of Korea |
| Authors: | J.Y. Lee, Inha University, Republic of Korea J.S. Choi, Inha University, Republic of Korea D.H. Cho, Inha University, Republic of Korea C.W. Chung, Inha University, Republic of Korea |
| Correspondent: | Click to Email |
The source/bias pulse-time modulated RF plasma has been introduced to progress further in convoluted challenges from conventional continuous wave (CW) plasma such as fatal etch damage, low etch selectivity, and etch residues. This modulated plasma means the plasma condition modified by a specific matching system which can change on-off duty ratio of 13.56MHz RF power and frequency on the specific duty ratio. Especially, since the magnetic materials used for magnetic random access memory (MRAM), which is a promising candidate for next generation semiconductor, have less reaction with even corrosive gases, this process can offer a prospective approach. Some researches on etch characteristics of magnetic materials using bias-pulse time modulated plasma has been reported, resulting in improved etch profiles compared to CW plasma . However, few studies on the magnetic materials using source-pulsed plasma can be found.
In this study, etch characteristics of nanometer-scale patterned magnetic tunnel junction stacks (MTJs), which is a critical component of MRAM, using the pulsed modulated RF source plasma were investigated. The MTJs consisted of TiN/Ta/CoFeB/MgO/CoFeB/Ta on the SiO2 substrate and E-beam resists of 70×70 nm2 were patterned on the TiN hardmasked MTJ stacks. In the plasma process, the non-corrosive gas mixture of CH4/O2/Ar was used. The effects of on-off duty ratio and frequency of pulsed plasma on the etch characteristics of MTJ stacks were examined.