AVS 52nd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuM

Paper PS-TuM9
Molecular Dynamics Investigation of the Etching of Passivated SiOCH Low-@kappa@ Dielectric Films

Tuesday, November 1, 2005, 11:00 am, Room 304

Session: Plasma Surface Interactions I
Presenter: V. Smirnov, SarovLabs, Russia
Authors: V. Smirnov, SarovLabs, Russia
A. Stengatch, SarovLabs, Russia
K. Gainullin, SarovLabs, Russia
V. Pavlovsky, SarovLabs, Russia
S. Rauf, Freescale Semiconductor, Inc.
P. Ventzek, Freescale Semiconductor, Inc.
Correspondent: Click to Email
Fluorocarbon plasmas are widely used for etching of dielectric thin films (conventional and low-@kappa@) in the microelectronics industry. Fluorocarbon radicals and ions are known to produce a nanometer-scale passivation layer on the dielectric surface, whereupon energetic ion bombardment leads to dielectric material etching. As the passivation films are extremely thin and in-situ monitoring is difficult during etching, very few experimental studies have been able to probe into the fundamental nature of fluorocarbon based etching of low-@kappa@ dielectrics. This paper reports about a computational molecular dynamics (MD) investigation of the etching of SiOCH low-@kappa@ dielectric films by CF@sub x@@super +@ (x=1, 2, 3), SiF@sub x@@super +@ (x=1, 2, 3), CHF@sub x@@super +@ (x=1, 2), and Ar@super +@ ions. The MD model is 3-dimensional and uses the velocity-Verlet method for particle acceleration. Psuodo-potentials for two and three body interactions of Si, O, C, H, F, and Ar have been assembled either using Gaussian based quantum chemistry computations or data available in the literature. The test structures for the MD studies are prepared by starting with crystalline Si and depositing mixtures of SiO@sub x@@super +@, CH@sub x@@super +@ and H@super +@ ions. Film stoichiometry and density can be controlled by means of ion fluxes and energies. A passivation layer is grown on the low-@kappa@ test structures through low energy fluorocarbon ion bombardment. Impact of energetic (100-300 eV) ions on passivated dielectric films is investigated in this paper, and modeling results are used to determine ion etching yields, nature of sputtered clusters, and their energy and angular distributions.