AVS 47th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS2-WeA

Paper PS2-WeA7
Modeling of Trench Filling During Ionized Metal Physical Vapor Deposition@footnote 1@

Wednesday, October 4, 2000, 4:00 pm, Room 311

Session: Feature Evolution
Presenter: J. Lu, University of Illinois at Urbana-Champaign
Authors: J. Lu, University of Illinois at Urbana-Champaign
M.J. Kushner, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
Ionized Metal Physical Vapor Deposition (IMPVD) is used to deposit metal seed layers into high aspect ratio trenches in semiconductor processing. Conformal deposition and filling of trenches require an optimized ratio of neutral to ion flux, and optimized energy and angular distributions of the precursors. In this paper, we report on a reactor scale to feature scale computational investigation of Cu IMPVD in which this optimization is discussed. The computational tools used are the 2-dimensional Hybrid Plasma Equipment Model (HPEM) and the Monte Carlo Feature Scale Model (MCFPM). The HPEM produces species densities and source functions in the bulk plasma, and the trajectories of ions and neutral species onto the substrate. The MCFPM uses these fluxes and trajectories to evolve a deposition profile while considering energy and angular dependent deposition and sputtering probabilities. A surface diffusion algorithm was developed to avoid artificial dendritic growth. Cu deposition will be discussed for an inductively coupled plasma using a dc magnetron target. Typical operating conditions are 10's mTorr Ar buffer gas, 100's to 1000's kW ICP and magnetron power, and 10's V substrate bias. For constant ICP power, conformality improved and the likelihood of keyholes decreased as magnetron power decreased due to an increase in the ion-to-neutral ratio in the reactant fluxes. Micro-voids are sometimes produced for these otherwise "good" conditions due to microtrenching which occurs by ion-reflection neutrals during resputtering of the deposited metal. Similar effects are seen by increasing buffer gas pressure to increase ionization fraction. The consequences of surface diffusion on the profile will also be examined. @FootnoteText@ @footnote 1@Work supported by TAZ, Novellus, AMAT, SRC and NSF.