AVS 51st International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS1-WeM

Invited Paper PS1-WeM7
Nano-Scale Pattern Transferring By Plasma Etching

Wednesday, November 17, 2004, 10:20 am, Room 213A

Session: Plasma in Nanoscale Applications
Presenter: Y. Zhang, IBM T. J. Watson Research Center
Authors: Y. Zhang, IBM T. J. Watson Research Center
C. Black, IBM T. J. Watson Research Center
K. Guarini, IBM T. J. Watson Research Center
T.J. Dalton, IBM T. J. Watson Research Center
Correspondent: Click to Email
Patterning challenges for the 22nm node and beyond in the ITRS roadmap requires precision etching of semiconductor nano-scale features at the sub-10nm regime. In this paper, we report the recent results of patterning true nano-scale features using plasma etching. A newly established method called "nanometer-scale pattern registration and alignment by directed diblock copolymer self assembly" was employed. Using this technique, large-scale (across 200 mm wafers) high-density (> 10E6/cm2) nano-scale features were produced; both holes and line arrays with 40nm pitch were fabricated. These structures are beyond any state-of-art conventional optical lithography and e-beam writing technologies. The nanometer holes & line arrays were used to study plasma etching characteristics and challenges for different materials (silicon, silicon dioxide, and silicon nitride) with different plasma chemistries (fluorine-, chlorine-, and bromine-based). Besides scaling of the feature size or critical dimension, the thickness of the film stacks to be etched were also scaled. The patterning of nano-scale line arrays was more challenging that the patterning of nano-scale hole arrays when using ultra-thin and ultra-narrow diblock polymer masks. Among the challenges for line arrays were: (1) deformation of the polymer masks (due to poor thermal conductivity and film stress); (2) depth limitations due to selectivity to the mask; and (3) line edge roughness, (LER). These challenges have not only made the pattern transferring more difficult (even with current state-of-art plasma etching tools), but also indicate that plasma etching may be approaching a limits as it is currently implemented. A few proposed limiting factors of current etching tooling, underlying principles of different chemistries, and processing parameters and their advantage and drawback to etching nanometer scale features will also be discussed.