Laser-induced fluorescence diagnosis of plasma processing sources

Laser-induced fluorescence ion diagnostics in light of plasma processing

“…LIF with diode lasers [4] can characterize the ion beam [5] and the beam source plasma. In addition, background neutrals through which the beam propagates may be ionized, causing a low temperature non-beam plasma [6].…”

“…A series of different fluorocarbon source gases were compared using flows selected to provide constant carbon equivalents. Cyclic isomers were used for C 4 F 8 and C 5 F 8 , and linear isomers were used for C 4 F 6 and C 3 F 6 . Results indicate that the F density increases with the F:C ratio of the source gas (Fig.…”

Laser-induced fluorescence measurements for plasma processing

“…1 shows how LIF signal diminishes with increasing pressure about 1 cm in front of the Veeco/Ion Tech rf ion source. Neutral gas is fed into the source (see [25] for source geometry) and the gas not released as ions comes out the accelerating grid along with the ion beam. A neutral gas cloud exists in front of the ion beam source, this gas cloud is available for charge exchange with the ion beam and produces a low density cold, non-drifting background plasma [25].…”

“…Neutral gas is fed into the source (see [25] for source geometry) and the gas not released as ions comes out the accelerating grid along with the ion beam. A neutral gas cloud exists in front of the ion beam source, this gas cloud is available for charge exchange with the ion beam and produces a low density cold, non-drifting background plasma [25]. Inside the source, as pressure is raised, the tail population electrons needed for metastable excitation probably are reduced in density and charge exchange distances become sub-centimeter so metastable ions which may be diagnosed in the visible by LIF become scarce.…”

“…Ion energy analyzers have been used to examine onedimensional ion distributions in the output of ion beam etching and deposition sources [22] and multidimensional energy distributions in helicon sources [23,24]. Ion distribution functions found inside ion beam etching and deposition sources have been studied with LIF [25].…”