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PEALD for TaN deposition. Investment Proposal. Aalto University: Oskari Elomaa, Jussi Lyytinen, Erkin Cura, Henri Nykanen VTI Technologies Oy: Petteri Kilpinen. Table of contents. Introduction to TaN and PEALD ALD applications TaN precursors Other process components Tool specifications
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PEALD for TaN deposition Investment Proposal Aalto University: Oskari Elomaa, Jussi Lyytinen, Erkin Cura, Henri Nykanen VTI Technologies Oy: Petteri Kilpinen
Table of contents • Introduction to TaN and PEALD • ALD applications • TaN precursors • Other process components • Tool specifications • Chamber specifications • Facilities • Financing
MOTIVATION • TaN thin film • Defect and residue free • Conformal, uniform, complex (3D) • Low resistivity (<500µcm) • Single precursor and plasma enhanced • Low temperature process (<500C)
1. Introduction to TaN and PEALD • Tantalum Nitride (TaN): • diffusion barrier in copperinterconnects • promising gate electrode • Atomic layer deposition (ALD): • deposition of down to one atomic layer thin coatings • high-aspect ratios • conformal, uniform films • self-limiting surface reactions • Plasma enhanced ALD (PEALD): • improved material properties • deposition at reduced temperatures
2. ALD Applications: • IC and Microelectronics • Gate oxide, barrierorprimerlayers, gateelectrode, siliconwafers, solarcells, microprocessors, diodes, transistors, sensors, flatpaneldisplays, magneticheads, memories • Diffusionbarriers • Gaspermeabilityreduction of plastics, surfacepassivation • Optics • Lenses • Nanotechnology • Decorative&protectivecoatings, primers for othercoatings
3. TaN precursors Precursors, reaction temperatures, and properties of Ta-N ALD films. Petra Alén, ACADEMIC DISSERTATION, 2005, Atomic Layer Deposition of TaN, NbN, and MoN Films for Cu Metallizations, Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, Finland.
TaN-PEALD process example • Kim et al.used the PEALD method to deposit TaN films. The deposition was accomplished by alternate exposures of the metal precursor TaCl5and the plasma of hydrogen and nitrogen mixture. • The N/Ta ratio of the films increased from 0.3 to 1.4 with increasing nitrogen partial pressure. • The cubic TaN phase was obtained with the N/Ta ratio between 0.7 and 1.3. The resistivity of the cubic TaN was typically 350-400 μΩ cm and the deposition rate was 0.24 Å/cycle. • The chlorine contents and resistivities depended on the plasma exposure time. Reasonably low chlorine content and low resistivity were obtained only when the plasma exposure time exceeded 5 s. • The films contained 5 to 10 at. % oxygen. H. Kim, A.J. Kellock, and S.M. Rossnagel, J. Appl. Phys. 92 (2002) 7080-7085.
4. Other process components • Substrates (Si, SiO2, Cu, Al…) • 200 mm wafers and other planar substrates • Complex 3D substrates • Powders and other porous substrates • Liquid sources (H2O, TMA, DEZ, TiCl4...) • Hot sources (TDMAT, TEMAH, TBOS, TaCl5) • Carrier and plasma gases (N2, Ar, H2)
5. Tool specifications • Substrate temperature range: 25 - 500 °C • Reaction chamber type: Single wafer plasma • Gas lines: Up to 8 (min 3) • Liquid sources: +5 °C to ambient up to 4 (min 2) • Hot sources: ambient to 500 °C up to 4 (min 2) • Plasma reactor: CCP 300 W (or similar) • Control system: PLC control with PC user interface
6. Chamber specifications Hot wall reaction chamber in a cold wall vacuum chamber
7. Facilities Example: • Normal factory ambient (IEC 204-1 and EN 60204-1) • Electrical supply 400 V/50 Hz • Compressed air • Space requirement 6 m2 • ALD system (L × W × H) 1325 × 600 × 1298 (mm) • electric cabinet (L × W × H) 1000 × 300 × 1600 (mm)
8. Budget • Basic thin film system 200 k€ • gas lines, sources, vacuum system, chiller, shipping, comissioning, spare parts • Reaction chamber (plasma) 50 k€ Total investment 250 k€ • Operational costs/year (everyday use)30 k€/year • Precursors 10 k€ • Gases 10 k€ • Facilities (rent, electricity, ventilation) 10 k€
Options for Equipment Purchase Beneq Oy: Thin Film System 200 Cambrigde NanoTech: FIJI Reference Institutes for the equipment • ETH Zürich • Paul Scherrer Institut • Tohoku University • The University of Texas at Dallas • Univ. of California • Max-Planck Institute In Finland • University of Helsinki • VTT Technical Research Centre of Finland • Lappeenranta University of Technology Picosun: Sunale-Rand Sunale-P Oxford Instruments: FlexAL and OpAL
PEALD for TaN deposition Aalto University: Oskari Elomaa, Jussi Lyytinen, Erkin Cura VTI Technologies Oy: Petteri Kilpinen