ELNC842 Thin Film Technology
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    Course Description

    This course introduces students to the theory and practice of vacuum deposition of thin films. Students will study gas physics as well as the fundamentals of high vacuum systems including system operation and design. Evaporation and sputtering technologies are examined and thin-film design, layout, and structures (such as conductors, resistors, and capacitors) are covered. Optical coatings will be examined. The course includes a laboratory component involving design,processing, and testing of ceramic based thin film electrical circuits as well as fabrication of thin film optical elements.

    See the NOTE at the end of this page regarding current course offerings in this subject

    Specific Elements Of Thin-Film Technology In This Course

     Laboratory components to accompany this material are also outlined on this page

    The Physics of Gases and Vacuum Systems

      * The fundamental nature of gases and gas flow
      * Gas Laws (e.g. Boyles Law) and applications
      * The concept of vapour pressure and how it applies to gases, liquids, and solids
      * The concept of conductance
      * Why a high vacuum is required (i.e. Mean Free Path)
    Vacuum Technology
      * Operational principles of various mechanical pumps as well as limitations
      * Operation of high vacuum pumps such as oil diffusion pumps
      * Backstreaming and cryotrapping of diffusion pumps
      * Principles of UHV pumps such as ion and getter pumps
      * Measuring vacuum pressures using various gauges (e.g. pirani, ion, etc.)
      * Leak detection and RGA
      * Design and operation of a practical vacuum system
      * Construction of vacuum systems including materials and couplings
      * Identify sources of contamination and leaks in a typical vacuum system
    Deposition Techniques
      * Evaporation Techniques (filaments, baskets, and boats)
      * E-Beam Techniques
      * Sputtering Techniques
      * Calculating thickness using Point-Source Load Calculations from Nomograph
      * Crystal Thickness Monitoring (In-Process)
    Electronic Structures in Thin Film
      * Materials available for conductors, resistors, and capacitors
      * Forming conductors on substrates using various processes
      * Techniques to form thin-film resistors
      * Capacitors
    Optical Structures in Thin Film
      * Materials available for optics (reflectors, dielectrics)
      * Physics of optics (e.g. principle of interference)
      * Design of antireflective coatings
      * Design of dielectric filters

    This course is offered in our post-diploma microelectronics program. Material in this course is also available in seminar format for industry short-courses. Contact the program coordinator for information on customized training we offer to industry.



    Our technician adjusts the deck which holds the source on the microelectronics lab Edwards High-Vacuum system. This system is used for vacuum deposition of thin films. It features a diffusion pump and liquid nitrogen cryotrap. The system is housed within our class-1000 cleanroom where thin films circuits as well as silicon wafers are fabricated.

    New For 2001! A complete retrofit of our thermal evaporator including:
    * A new and more efficient diffusion pump
    * A new computerized vacuum controller allowing unattended pump-downs
    * Multi-filament capability allowing one-step optical element fabrication

    In the near future we anticipate adding a CVC four-target sputtering system to our inventory. This system is production-sized allowing over 100 substrates to be deposited at once. The system supports RF as well as DC sputtering. It will be housed in our class-1000 cleanroom beside the Edwards thermal evaporator already in use.

    Possible Labs

    Note that actual labs offered will depend on time and equipment availability.

    Basic Thin Film Techniques
    Using the Edwards thermal evaporator a thin film of pure aluminum will be applied to a ceramic substrate. Lab work includes cleaning the substrate using the plasma cleaner as well as basic evaporation technique including vacuum system and source preparation, vacuum system operation, and thickness monitoring during deposition using a quartz crystal monitor.

    Electrical Structures in Thin Film I
    Several conductors and resistors will be fabricated in aluminum and/or nickel-chromium using thermal evaporation and/or sputtering techniques. Students will deposit a layer of Ni-Cr resistive material or aluminum (a conductor), apply resist, and etch a test pattern using photolithographic techniques. Analysis will include consistency of the layer as well as effects of the structures used such as corners on resistivity (ohms per square).

    Electrical Structures in Thin Film II: Project
    An audio amplifier will be fabricated in thin-film on a ceramic substrate. The amplifier will use surface-mount components except for several low-value emitter resistors used in the output stage which will be fabricated on the substrate itself using the base aluminum material (i.e. the resistivity of the aluminum conductor will be used to allow fabrication of these resistors). Students will be responsible for deposition, layout (CAD), and photolithography, and assembly of the project.

    Optical Structures I
    A simple single-layer anti-reflective coating will be applied to a glass substrate. Analysis will include before and after reflectivity measurements as well as spectral characteristics of the film.

    Optical Structures II
    Using alternating layers of aluminum and dielectric a thin-film dielectric filter will be constructed. Unlike traditional optical filters which work by absorbing unwanted wavelengths of light these filters use the principle of constructive and descructive interference of different wavelengths of light to accomplish filtration. A structure composed of a sandwich of aluminum-dielectric-aluminum will be fabricated. The aluminum films are thin enough (about 30 nm) to be semi-transparent. Various flourides (calcium or lithium) and chlorides may be used for a dielectric layer as well as sodium hexafluoroaluminate. Students will analyze the product filter using a spectrograph to determine centre wavelength as well as spectral width - by determining these characteristics other parameters such as the reflectivity of the aluminum-dielecric interface may be calculated.

    Lab Equipment used in this course

    Descriptions and photos of equipment used in depositing thin films in our microelectronics laboratory

    Branson/IPC Plasma Cleaner used to clean substrated prior to deposition
    Edwards high-vacuum deposition system including gauges and thickness monitor
    Photolithography, Resist Application, and Etching at the 'wet bench'

    NOTE:

    This course is not offered in 2004.

    For information on a similar course (PHTN1432) offered within the Photonics programs Click Here. PHTN1432 is an involved course combining vacuum technology with thin-film design and focussing on optical applications such as antireflective coatings and dielectric filters and mirrors. The college has added a new Mass, Optical, and Infrared Spectroscopy Laboratory in V14A which includes a turbomolecular pumping facilty used for pumping gas discharge tubes and reproessing laser tubes. The system features a 200amu mass spectrometer/RGA with high-sensitivity channel electron multiplier. Equipment in the cleanroom has been upgraded as well to include a new four-source diffusion-pump based thermal evaporator (the Bendix), and will soon include a new cryopumped sputtering and e-beam system.

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    Copyright (C) Niagara College, Canada, 2003
    This course is part of the TECHNOLOGY division