AVS 56th International Symposium & Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThA

Paper PS2-ThA2
On-wafer Monitoring for UV/VUV Photon Irradiation during Plasma Processes

Thursday, November 12, 2009, 2:20 pm, Room B2

Session: Plasma Diagnostics, Sensors, and Control II
Presenter: B. Jinnai, Tohoku University, Japan
Authors: B. Jinnai, Tohoku University, Japan
S. Fukuda, Tohoku University, Japan
H. Ohtake, Tohoku University, Japan
E.A. Hudson, Lam Research Corp.
S. Samukawa, Tohoku University, Japan
Correspondent: Click to Email
Plasma processes are indispensable for the fabrication of ULSI devices. In plasma, there are many activated species, such as charged particles, radicals, and photons. By using these species, etching and film deposition can be achieved. UV/VUV photon irradiation from plasma can cause serious problems because UV/VUV photons can be absorbed in films and generate defects, which may cause degradations of device characteristics. In order to overcome this issue, it is important to understand characteristics of UV/VUV photon irradiation from plasma, such as UV/VUV spectrum and its absolute intensity (photon flux). To investigate these characteristics of UV/VUV photon irradiation from plasma, a VUV spectrograph can be used. A VUV spectrograph is, however, generally expensive and large system, so it is difficult to install. Also, spectra data obtained from a spectrograph is not always corresponding to the information of UV/VUV photon irradiation incident to wafers, due to the different field of view. In this study, we measured plasma properties on a commercial capacitively-coupled dielectric etch reactor using a VUV spectrograph and our developed on-wafer monitoring technique. The on-wafer measurement is based upon plasma-induced current in SiO2 and SiNx thin films. Furthermore, we develop the neural network (NN) modeling method based on the data from our developed on-wafer monitoring technique. By using this method, we could successfully predict the profiles of the UV/VUV spectrum. From the current measured by the on-wafer monitoring technique, we calculated the absolute intensity of UV/VUV photons. The on-wafer monitoring technique has many advantages for the investigation of UV/VUV photon irradiation during plasma processes, and can be applied to the prediction of device damages induced by UV/VUV photon irradiation from plasma.