| AVS 62nd International Symposium & Exhibition | |
| Plasma Science and Technology | Monday Sessions |
| Session PS-MoM |
| Session: | Advanced FEOL/Gate Etching |
| Presenter: | Jason Peck, University of Illinois at Urbana-Champaign |
| Authors: | A. Peck, University of Illinois at Urbana-Champaign G.A. Panici, University of Illinois at Urbana-Champaign I.A. Shchelkanov, University of Illinois at Urbana-Champaign D.N. Ruzic, University of Illinois at Urbana-Champaign |
| Correspondent: | Click to Email |
Dry etch assisted by laser (DEAL) of silicon and silicon dioxide via Ar/SF6/C4F8/O2 capacitively-coupled plasma was studied, with goals including form control for sub-22 nm features and uniformity for 450 mm wafer processes. The first phase of the work confirmed the feasibility of the proposed concept. The second phase of the work was focused on pulse frequency, length and wavelength influence on etching rate. Two lasers with different repetition rates, wave lengths and pulse widths were used. The first one is a (2.5 – 7 ns FWHM) Nd:YAG laser with repetition rate of 100 Hz. The Nd:YAG laser was capable to produce emission at 1064, 532 and 266 nm wavelengths. The second laser was a 1043 nm IMRA laser with 300 fs pulses and 1 MHz pulse rate. Continuous wave (CW) laser systems were also tested.
The etch rate enhancements were determined. The predominant laser-assisted etch mechanism was interpreted to be electrochemical, with electron-hole pairs catalyzing chemical etching at the surface. The influence of laser repetition rate was studied in both SF6 and C4F8 etch. The beam intensity profile influence onto etch pattern was studied. In all cases, an emphasis on low power density kept the experiments well under the ablation threshold, minimizing pyrolytic damage by the incident beam. Impact on current industry processes will be discussed.