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  • Mar
    12

    Mechanical Engineering- Simpson Lecture: Ares Rosakis

    McCormick - Mechanical Engineering

    3:00 PM L211, Technological Institute

    EVENT DETAILS

    Ares Rosakis, PhD
    Simpson Distinguished Visiting Professor

    Monday, March 12, 2018

    3:00pm - 4:00pm

    Reception following in Cohen Commons

    Got Stress? Visualizing and Inferring Film Stresses in Patterned Wafers

    ABSTRACT:

    The Caltech-developed “Coherent Gradient Sensor (CGS)” method is an optical shearing interferometer sensitive to surface slope changes of plates undergoing deformations and was initially used in conjunction with high-speed photography for the study of dynamic failure of opaque structural materials.
    In the first section of this lecture we describe an entirely different application of CGS of relevance to the microelectronics and opto-electronics industry. Here we present CGS as a unique inspection and reliability tool used for the rapid, full-field, and in-situ measurement of deformation states (slopes and curvature components) in thin film-wafer substrate systems and for the subsequent inference of non- uniform stresses in thin films and thin film structures deposited on such substrates. We also demonstrate the unique ability of CGS to produce curvature maps in large, 300mm patterned wafers during various stages of processing.
    In the second part of the lecture we describe how classical analytical approaches (e.g. the classical Stoney formula), relating local stresses to local curvatures in such systems fail in the presence of misfit stain, temperature and thin film thickness, non-uniformities. To mitigate this we present a series of new analytical models (developed in collaboration with Northwestern colleagues) capable of relating non-uniform curvature components to arbitrarily non-uniform stress states resulting from the presence of geometrical, misfit strain and temperature non-uniformities. A striking outcome of the entire class of such models is that film stresses, in the presence of such non- uniformities, are found to always depend non-locally on system curvatures thus necessitating full field wafer curvature recording rather than point-wise measurements. This remarkable fact makes CGS (a full field rather than a point-wise method of measuring curvatures) a perfect optical technique to be used, in conjunction with the analytical models presented here, for accurate film stress inference and for stress management in realistic cases involving the various processing steps of large, 300mm Wafers.

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    TIME Monday, March 12, 2018 at 3:00 PM - 4:00 PM

    LOCATION L211, Technological Institute    map it

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    CONTACT Theresa Santos    tami.santos@northwestern.edu EMAIL

    CALENDAR McCormick - Mechanical Engineering

  • Apr
    22

    ME512 Distinguished Speaker Seminar Marcia K. O'Malley

    McCormick - Mechanical Engineering (ME)

    3:00 PM LR3, Technological Institute

    EVENT DETAILS

    TIME Monday, April 22, 2024 at 3:00 PM - 4:00 PM

    LOCATION LR3, Technological Institute    map it

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    CONTACT Jeremy Wells    jeremywells@northwestern.edu EMAIL

    CALENDAR McCormick - Mechanical Engineering (ME)

  • Apr
    30

    ME Alumni Seminar Series- Apostolos Karafillis

    McCormick - Mechanical Engineering (ME)

    2:00 PM 1.350, Ford Motor Company Engineering Design Center

    EVENT DETAILS

    TIME Tuesday, April 30, 2024 at 2:00 PM - 3:00 PM

    LOCATION 1.350, Ford Motor Company Engineering Design Center    map it

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    CONTACT Jeremy Wells    jeremywells@northwestern.edu EMAIL

    CALENDAR McCormick - Mechanical Engineering (ME)

  • May
    3

    Russ Tedrake, MIT and Toyota Research Institute, "Dexterous Manipulation with Diffusion Policies"

    Center for Robotics and Biosystems (CRB)

    11:30 AM M416, Technological Institute

    EVENT DETAILSmore info

    TIME Friday, May 3, 2024 at 11:30 AM - 12:30 PM

    LOCATION M416, Technological Institute    map it

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    CONTACT Amy Nedoss    amy.nedoss@northwestern.edu EMAIL

    CALENDAR Center for Robotics and Biosystems (CRB)

  • May
    8

    Extending Care: A Conversation about Conservation and Futurity

    Block Museum of Art

    6:00 PM Block Museum of Art, Mary and Leigh

    EVENT DETAILSmore info

    TIME Wednesday, May 8, 2024 at 6:00 PM - 7:30 PM

    LOCATION Block Museum of Art, Mary and Leigh    map it

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    CONTACT Block Museum of Art    block-museum@northwestern.edu EMAIL

    CALENDAR Block Museum of Art

  • Jun
    10

    Northwestern Engineering PhD Hooding and Master's Degree Recognition Ceremony

    McCormick School of Engineering and Applied Science

    9:00 AM Welsh-Ryan Arena

    EVENT DETAILSmore info

    TIME Monday, June 10, 2024 at 9:00 AM - 11:00 AM

    LOCATION Welsh-Ryan Arena   

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    CONTACT Amy Pokrass    amy.pokrass@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science

  • Jun
    10

    Northwestern Engineering Undergraduate Convocation

    McCormick School of Engineering and Applied Science

    2:00 PM Welsh-Ryan Arena

    EVENT DETAILSmore info

    TIME Monday, June 10, 2024 at 2:00 PM - 4:00 PM

    LOCATION Welsh-Ryan Arena   

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    CONTACT Amy Pokrass    amy.pokrass@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science