AVS 53rd International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS2+TF-WeM

Invited Paper PS2+TF-WeM1
Beam Activation for Atomic Layer Deposition of Ta-Based Barriers on Low-k Dielectric Surfaces

Wednesday, November 15, 2006, 8:00 am, Room 2011

Session: Plasma Deposition
Presenter: P.S. Ho, The University of Texas at Austin
Authors: P.S. Ho, The University of Texas at Austin
J. Liu, The University of Texas at Austin (presently: Tokyo Electron America Inc.)
J. Bao, The University of Texas at Austin
H. Shi, The University of Texas at Austin
Correspondent: Click to Email
Atomic nitrogen and hydrogen beams were investigated as surface pre-treatment and process enhancement techniques for atomic layer deposition (ALD) of tantalum nitride barrier layer on low k dielectric surfaces. Electron cyclotron resonance (ECR) plasma induced atomic nitrogen and hydrogen species were applied to a methyl silsesquioxane (MSQ) and organic polymer low k surfaces prior to and during ALD growth. In-situ XPS studies of the evolution of the low k surface chemistry revealed an initial transient growth region controlled mainly by the substrate surface chemistry. For MSQ surfaces, pre-treatment with atomic beams, particularly with nitrogen atoms, was found to enhance significantly the chemisorption of the TaCl5 precursor on the low k surface. The enhancement was attributed to the dissociation of the weakly bonded methyl groups from the MSQ surface followed by nitridation with the atomic nitrogen species. For the organic polymer surface, the initial interaction was manifested by the formation of a charge transfer complex as a result of the interaction between Ta and the aromatic structure. In the subsequent linear growth region, atomic hydrogen species was able to reduce the chlorine content under appropriate temperature and with sufficient purge. The application of beam activation for pore sealing on porous low k surface will also be discussed.