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Photoresist etching mechanisms in O2 abd SF6 microwave plasmas are investigated using x-ray photoelectron spectroscopy (XPS) and etch rate measurements. Experiments are performed in a microwave multipolar plasma using an electron cyclotron resonance at 2.45 GHz and independent rf biasing at 13.56 MHz. The photoresist etch rates are studied as a function of the parameters of the plasma polymer interaction. As in an O2 plasma, the etch rate in SF6 exhibits a two-step evolution with ion energy as well as a monolayerlike adsorption of atomic fluorine on photoresist. The relationship between the surface mechanisms deduced from the etch kinetics and the surface compositions analyzed by XPS is explored. The effect of reactive species concentration, intensity of ion bombardment, and surface temperature on etching and/or degradation of the photoresist is investigated. In particular, the phenomenon of resist damage, described as a graphitization of the polymer layer, is shown to appear when the mechanical effects of ion bombardment become significant with respect to the chemical effects.

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We have studied the transformation of a polysiloxane film induced by high temperature annealing and by 248 and 193 nm excimer laser irradiation. Auger electron and x-ray photoelectron spectroscopy have been used to study the Si, O, and C profiles and the Si-O valence band structure before and after transformation. We suggest that laser induced transformation results from localized heating and oxidation of the Si-O chains coupled with a breakdown and oxidation of previously attached benzene groups into volatile gaseous products which diffuse out of the film.

Bulk resist degradation under O2 or Ar plasma exposure is experimentally demonstrated. The degradation mechanisms are analyzed in Ar plasma and a synergistic effect of ion bombardment is presented. Mechanical effects of ion bombardment lead to a surface degradation of the resist whereas thermal effects allow the extension of the degradation to the bulk. Self-diffusion of chains is demonstrated which clearly emphasizes the role of the viscoelastic properties in polymer degradation.