AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoM

Paper PS-MoM11
A General Predictive Semi-Empirical Feature Profile Simulator

Monday, November 2, 1998, 11:40 am, Room 318/319/320

Session: Feature Evolution
Presenter: D.J. Cooperberg, Lam Research Corporation
Authors: D.J. Cooperberg, Lam Research Corporation
V. Vahedi, Lam Research Corporation
Correspondent: Click to Email
A multiple process, semi-empirical, 2-dimensional, feature profile evolution simulator has been developed and is being used to conduct mechanistic studies of processes including oxide etch, silicon etch, PECVD, and IPVD. The feature surface is advanced with a shock-tracking algorithm@footnote 1@. The simulator employs a Monte Carlo based scheme for determining particle fluxes to the surface. Trajectories of ions, depositing and etching species are followed. Etching and depositing agents are modeled using a sticking coefficient model. A Langmuir site balance model is employed at the discretized feature surface to compute rates. For oxide etch, an algorithm for simultaneous etching and deposition has been implemented which allows for the modeling of a steady-state fluorocarbon film during etching@footnote 2@. Physical sputtering, ion-assisted etching and scattering of ions at the feature surface are modeled along with redeposition of sputtered material. Ion energy and angular distributions can be supplied to the profile simulator from self-consistent sheath models or simulations. Parameters such as stickling coefficients, sputter and etch yields which are associated with each material (i.e. photo-resist, oxide, polymer, metal) within a feature have been determined in part by experiment. Polymer deposition experiments have been performed to determine polymer sticking coefficients and study the role of ion-assisted deposition. Sputtering experiments have been performed to carefully measure angular and energy dependence of sputter yield on resist and oxide. Experimental results from IPVD have also been used to determine the yield and threshold for physical sputtering. Parameters not yet measured through experiment have been chosen with the use of a calibration routine which determines the values which lead to optimal agreement between simulation and digitized SEM data. The mechanistic and the semi-empirical calibration approaches have given our profile simulation tool a predictive capability. Feature characteristics such as taper, bow, necking, etchstop, facet angles, step-coverage and trenching are captured with appropriate process parameters. @FootnoteText@ @footnote 1@Hmamguchi S., "Mathematical methods for Thin Film Deposition Simulations", in "Modeling of Film Deposition for Microelectronic Applications," Thin Films, vol. 22, ed. by S. Rossnagel, (Academic Press Inc., San Diego, 1996), pp. 81-115 @footnote 2@ Rueger, N.R.; Beulens, J.J.; Schaepkens, M.; Doemling, M.F.; Mirza J.M.; Standaert, T.E.F.M.; and Oehrlein, G.S., Role of steady state fluorocarbon films in the etching of silicon dioxide using CHF@sub 3@ in an inductively coupled plasma reactor. Journal of Vacuum Science & Technology A (Vacuum, Surfaces, and Films), July-Aug. 1997, vol.15, (no.4):1881-9.