AVS 57th International Symposium & Exhibition
    Plasma Science and Technology Monday Sessions
       Session PS1-MoA

Paper PS1-MoA10
High Selectivity SiN Etching with Low Damage by RLSA Microwave Plasma

Monday, October 18, 2010, 5:00 pm, Room Aztec

Session: Advanced FEOL / Gate Etching I
Presenter: M. Inoue, Tokyo Electron, LTD., Japan
Authors: M. Inoue, Tokyo Electron, LTD., Japan
M. Sasaki, Tokyo Electron, LTD., Japan
Y. Ohsawa, Tokyo Electron, LTD., Japan
Correspondent: Click to Email

New materials such as High-K/Metal Gate and three-dimensional structures such as Tri-Gate have been introduced at the 22nm node and beyond. In addition, high selectivity and reduced Plasma Induced Damage (ex. Charge up damage and Si crystal damage, etc.) are required of the etching process. Especially, Fin Spacer of Tri-Gate is required high selectivity to thin oxide. RLSA (Radial Line Slot Antenna) microwave plasma has several features that overcome these new challenges. The characteristics of RLSA plasmas include high density, low electron temperatures and low plasma potential. In addition, Radical/ion ratio is higher than conventional plasma source. These characteristics enable highly selective etching with decreased Plasma Induced Damage on the wafer surface. A high SiN/SiO selectivity process has been achieved due to the features of RLSA plasma and low bias (low Vpp) conditions.

We have recently developed a high selective SiN/Si etching process under low bias conditions. It is thought that the mechanism for this etch includes minimum oxidation (native oxide level) of the Si surface to SiO, creating a highly selective etch similar to the SiN/SiO process that was previously developed.