Characterization of an epoxy filler for piezocomposites compatible with microfabrication processes

Anne L. Bernassau, David Hutson, Christine E. M. Demore, Sandy Cochran

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    Miniature ultrasound transducer arrays that can operate at frequencies above 30 MHz are needed for high-resolution medical imaging. One way to achieve this is with a kerfless structure based on 1-3 connectivity piezocomposite with the electrodes defined by photolithography. To achieve this, not only does the composite need planar, parallel, and smooth surfaces, but it must also be made with an epoxy filler compatible with the chemicals, heat, and vacuum required for photolithography. This paper reports full characterization of an epoxy suitable for fine-scale kerfless array fabrication, including photolithographic processing. Material properties have been investigated as a function of cure temperature and for compatibility with solvents. By increasing the cure temperature, the crosslinking between the epoxy and the hardener increases, resulting in a higher glass transition temperature. The cured epoxy consequently has better resistance to both heat and solvents. An elevated cure temperature, near 100 degrees C, is required to optimize material properties for photolithography on 1-3 piezocomposites. The acoustic properties of the epoxy have also been studied. These are similar to other epoxies used in piezocomposite fabrication and no significant changes have been observed for the different cure temperatures.

    Original languageEnglish
    Pages (from-to)2743-2748
    Number of pages6
    JournalIEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
    Volume58
    Issue number12
    DOIs
    Publication statusPublished - Dec 2011

    Keywords

    • Composite transducers
    • Ultrasound
    • Epoxy adhesive
    • Cure temperature
    • Material properties
    • Acoustic properties
    • High frequency array
    • Photolithography

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