A comprehensive Monte Carlo program (piber) has been developed for the simulation of ion beam exposure of resists. piber has been used to study ion ranges, backscattering coefficients, and energy-loss distribution data for various combinations of incident ions and multilayered targets. For lithographic applications, the spatial ion energy-loss distribution in polymethyl methacrylate (PMMA) generated with piber for a δ-function exposure is convoluted with realistic incident ion beam shape (Gaussian, square, etc.) to produce latent images. A string development model is then used to generate developed ion beam exposure profiles in PMMA. The developed profiles for isolated lines have been studied as a function of parameters such as ion energy, resist thickness, and exposure dosage. Closely spaced lines have also been simulated in order to study proximity effects. It is demonstrated that proximity problems are greatly reduced in comparison with electron beam exposed patterns.

We report the properties of an inorganic material as a positive ion-beam resist. The ion beam (H+) exposure characteristics of g–GexSe1−x chalcogenide amorphous glass films were investigated. These films exhibit higher sensitivity as ion-beam resists than they do as positive photo- and electron-beam resists. Pattern replication and delineation with this resist material is demonstrated with a conformal gold mask.

We report preliminary results on the fabrication of 400- and 2600-Å deep lines in polymethyl methacrylate (PMMA) by means of H+ exposure through a holographically produced fine conformal gold mask.

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The technique of ion beam lithography coupled with calculations using a Monte Carlo computer program for ion penetration in solids have been used to obtain various range parameters of hydrogen, helium, lithium, beryllium, boron, and carbon ions in polymethyl methacrylate resist. In the experiment, the resist is bombarded with ions and then developed in a 1 : 1 solution of methyl isobutyl ketone and isopropyl alcohol with the developed depth monitored as a function of time. The saturated developed depth is approximated as the mean path length of the ion in the resist. The physical basis of this approximation is discussed. The projected ranges and straggles of the specified ions at energies of 5–300 keV obtained by fitting the experimental data to the total range using a Monte Carlo program are presented. These range data can be used as guidelines to determine the resist mask thickness for ion implantation and for choosing resist thickness in ion beam lithography.