Silicon Photonic Gas Sensing
William M. J. Green, Eric J. Zhang, et al.
OFC 2019
A plasma-enhanced cyclic etch process utilizing sequential cycles of Cl2 (deposition) and He/H2 (etch) chemistries separated by purge steps was used to pattern TiN and TaN lines using an organic planarization layer mask at a 100 nm critical dimension and a 200 nm pitch. Etch rates (ERs) were found to vary from 3.5 to 7 nm per cycle for TaN and 5-7.3 nm per cycle for TiN, depending on the addition of H2 to the etch step. The cyclic etch process displayed several key advantages over a continuous wave plasma process, such as no residual material in TiN patterning and reduced veiling due to redeposition in the TaN features. Analysis of the optical emission spectra collected indicated a key mechanistic difference between etching of the two materials, with TiN etching mainly controlled by the residence time of Cl species and TaN etching rate-limited by physical bombardment to facilitate Ta-Cl formation. Tailoring of the feature profiles and control of the etch rate per cycle (ER/cycle) were demonstrated through manipulation of the Cl and H2 residence times.
William M. J. Green, Eric J. Zhang, et al.
OFC 2019
Tymon Barwicz, Yoichi Taira, et al.
IEEE JSTQE
Kenji Ishikawa, Tatsuo Ishijima, et al.
Japanese Journal of Applied Physics
W. Chien, Lynne Gignac, et al.
IMW 2019