10:45 AM - 11:00 AM
△ [5a-A413-7] Excitation kinetic model for argon process plasma diagnostics by spectroscopic measurement based on collisional-radiative model
Keywords:process plasma diagnostics, optical emission spectroscopic measurement, collisional-radiative model
Low-pressure discharge Argon(Ar) plasma is widely applied for semiconductor manufacturing engineering, etc. We would like to establish diagnostic method of electron temperature Te and electron density Ne by optical emission spectroscopic(OES) measurement based on collisional-radiative(CR) model. In the present study, the excitation kinetic model for the Ar plasma is examined.
In the CR model, excited-state number densities are determined by Te and Ne. However, we cannot obtain them explicitly. We must make the simplified excitation kinetic model and determine the diagnostic equations.
We made the excitation kinetic model as follows for pressure = 1.0 Torr (1.3 × 102 Pa) and atomic temperature= 4.3 × 10-2 eV. (1) To substitute 1.0 ≤ Te [eV] ≤ 4.0, 1.0 × 109 ≤ Ne [cm-3] ≤ 1.0 × 1012 for the CR model. (Threshold value = 10% of the maximum of the population.) (2) To extract the elementary processes for every excited state. (3) To make the equations of equilibrium of population for every excited state. (4) By the excitation kinetic model without atomic collisions, to make the equations of population balance that have only excited states emitting lines in the wavelength region detected easily.
We found that the time evolution of the excited state 6p’ is described with the number densities of the excite states 4p’[3/2]1,2, 19 (5p’), 21 (4d’+6s’), 24(6p’), 26(5d’+7s’) and 30(7p’) in our model without atomic collisions. The error of the model becomes remarkable for the high Te and Ne region. It is concluded that the model without atomic collisions is only valid for Ne >~ 1011 cm-3. However, if we would like to apply the model with atomic collisions to make the population balance exact, we must also know the number density of the level that is difficult to obtain by the OES measurement.
In the CR model, excited-state number densities are determined by Te and Ne. However, we cannot obtain them explicitly. We must make the simplified excitation kinetic model and determine the diagnostic equations.
We made the excitation kinetic model as follows for pressure = 1.0 Torr (1.3 × 102 Pa) and atomic temperature= 4.3 × 10-2 eV. (1) To substitute 1.0 ≤ Te [eV] ≤ 4.0, 1.0 × 109 ≤ Ne [cm-3] ≤ 1.0 × 1012 for the CR model. (Threshold value = 10% of the maximum of the population.) (2) To extract the elementary processes for every excited state. (3) To make the equations of equilibrium of population for every excited state. (4) By the excitation kinetic model without atomic collisions, to make the equations of population balance that have only excited states emitting lines in the wavelength region detected easily.
We found that the time evolution of the excited state 6p’ is described with the number densities of the excite states 4p’[3/2]1,2, 19 (5p’), 21 (4d’+6s’), 24(6p’), 26(5d’+7s’) and 30(7p’) in our model without atomic collisions. The error of the model becomes remarkable for the high Te and Ne region. It is concluded that the model without atomic collisions is only valid for Ne >~ 1011 cm-3. However, if we would like to apply the model with atomic collisions to make the population balance exact, we must also know the number density of the level that is difficult to obtain by the OES measurement.