| This thesis summarizes results obtained during mechanistic studies of inductively coupled fluorocarbon plasma etch processes, which find applications in the fabrication of contact holes and trenches in SiO2 layers in semiconductor device manufacturing. The obtained mechanistic insights are anticipated to be of value to etch process optimization and inductively coupled fluorocarbon plasma etch reactor design.; In systematic studies the effects of interactions of the plasma with the inductively coupled plasma reactor walls and coupling window on the etching processes were investigated. In the presented work SiO2, Si 3N4, and Si substrate etch processes were found to be strongly dependent on the reactor wall temperature dependent fluorocarbon deposition rate on reactor walls and on window erosion effects that are due to capacitive coupling from induction coil to the plasma.; The mechanisms involved in the etch processes on substrates were investigated in detail. Based on the results obtained during studies in which blanket SiO 2, Si3N4 and Si samples were etched, a general etch mechanism has been formulated. The mechanism describes how the substrate etch rates depend on the thickness of fluorocarbon films that are present during steady-state etching conditions on the SiO2, Si3N4 and Si samples. The mechanism explains why SiO 2 surfaces are covered with a relatively thin fluorocarbon film (<1.5 nm), while Si is covered with a relatively thick fluorocarbon film (2 nm to 7 nm), and that Si3N4 is intermediate between SiO 2 and Si (covered with 1 to 4 nm of fluorocarbon material). Further, the mechanism is also found to explain the observed angular dependence of SiO2 and Si3N4 etch rates.; In the studies on SiO2 contact hole formation, mechanisms that cause the feature etch processes to deviate from the blanket etching process have been examined. Important SiO2 feature etching effects have been found to be related to differential charging effects that result from the electron flux to the substrate to be more isotropic than the ion flux. In addition to differential charging effects, deviations from the blanket etch process have been suggested to be related to reduced fluxes of etch and deposition precursors in features. |
