AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS2-MoA

Paper PS2-MoA2
Un-Collided Beam Mass Spectrometric Measurements in C@sub 2@F@sub 6@ and CHF@sub 3@ Dielectric Etch Discharges

Monday, November 2, 1998, 2:20 pm, Room 318/319/320

Session: Diagnostics I
Presenter: J. RaviPrakash, The Pennsylvania State University
Authors: J. RaviPrakash, The Pennsylvania State University
R.C. McGrath, The Pennsylvania State University
G.A. Hebner, Sandia National Laboratories
Correspondent: Click to Email
Relative concentrations of reactive ions, neutral radicals and etch/resist products in dielectric etch chemistries have been measured using an uncollided beam mass spectrometer (Hiden EQP). Measurements were made in C@sub 2@F@sub 6@ and CHF@sub 3@ discharges produced in an inductively coupled research reactor operating with power densities, pressures, gas compositions and wafer materials typical of those found in etch processing tools. For C@sub 2@F@sub 6@ discharges we find that CF@sub 3@@super +@ is consistently the dominant fluorocarbon ion present, in agreement with published cross sections for dissociative ionization. Significant concentrations of CF@super +@, CF@sub 2@@super +@, and C@sub 2@F@sub 5@@super +@ are also observed. We will report on differences observed between our measurements of fractional yields for these reaction products and those expected from published dissociative ionization cross sections. Notable changes have been observed in concentrations of C@sub x@F@sub y@ species and of SiF@sub x@ etch products in the presence of photoresist. In CHF@sub 3@ discharges the dominant ion species are CF@sub 3@@super +@ and CHF@sub 2@@super +@. Smaller concentrations of CF@sub 2@@super +@, CF@super +@ and HF@super +@ are also observed. For each of the etch chemistries investigated, variation of species concentrations with changing power (100-400 W) and pressure (5-40 mTorr) were measured. We will report on discharge conditions which produce the maximum reactive ion species production within the processing reactor volume.