Gold films were deposited on quartz-crystal microbalances by decomposing C7H7F6O2Au (dimethyl gold hexafluoroacetylacetonate) with 2–10-keV Xe+, Kr+, Ar+, Ne+, or He+ ion beams. The number of molecules decomposed per incident ion (i.e., the total decomposition yield) was determined as a function of ion mass and energy. The total decomposition yield increases with increasing ion mass and ion energy, and is approximately proportional to the nuclear stopping power. A binary collision model and a thermal spike model are developed that relate the energy deposited by the ion, at the substrate surface, to the total number of molecules decomposed. Both models predict total decomposition yields that are in reasonable agreement with the experimental measurements; however, the variation of total yield with changes in ion mass and energy are best described by the binary collision model. The success of both models demonstrates that the energy deposited into the substrate surface through the ion-solid interaction is responsible for the decomposition of adsorbed molecules.
The exposure characteristics of six polymer resists to 1.5 MeV H+, He+, and O+ ions and to 20 keV electrons were measured. The resists used were polystyrene (PS), polymethyl methacrylate (PMMA), PMMA mixed with 20% of a copolymer of vinyl acetate and vinyl chloride (VMCC), poly(glycidyl methacrylate-co-3-chlorostyrene) (GMC), poly(butene-1-sulfone) (PBS), and a novolac. The deposited energy per unit volume required to expose a resist was found to be a function of the spatial energy dissipation rate of the ion in the resist. This has been accounted for in terms of the nature of the energy distribution around the primary particle track in conjunction with whether the resist requires the activation of a single site or two adjacent sites to produce exposure.
Range profiles for 300-and 475-eV 4 He + ions implanted in situ in tungsten at 60, 61, 80, 90 K were measured, directly and absolutely, employing an atom-probe field-ion microscope. A mean range (x) of 40±4 A and a parent standard deviation (a) of 20 to 36 A was obtained for 300-eV *He + ; values of x and a of 56 ±6 A and 37 to 42 A, respectively, were determined for 475-eV 4 He + . The existence of an isolated and immobile interstitial 4 He atom was established and an enthalpy change of migration of 0.24 and 0.32 eV was determined.
Presently available nanosecond laser based tools for removing Cr defects from photomasks have proven inadequate to the task due to the thermal nature of the ablation process which produces metal splatter, haze, reduced transmission, and pitting of the quartz substrate. These problems are virtually nonexistent when employing femtosecond pulses of light to ablate Cr defects in a nonthermal process. Photomasks repaired with ultrashort light pulses exhibit transmission approaching 100%, no observable glass damage, and exceptional spatial resolution. We have built a femtosecond pulsed laser mask repair system which is presently operating successfully in a manufacturing environment.
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