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  • 1.  Au thickfilm for hybrid circuits

    Posted 03-06-2023 16:11

    I am evaluating some Au thickfilm hybrid circuits that are experiencing poor wire bond strength and plug outs post wire bonding. Cross sectional analysis of the Au thickfilm shows isolated particles in the Au that are Cd and Bi rich. I understand that these elements are added to the Au thickfilm for adhesion issues to the ceramic substrates but I do not think this should be "isolated" individual particles. first time I am looking at au thickfilm so any input would be greatly appreciated. see image below

     



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    Gerard O'Brien
    president
    S T and S Group
    Richmond KY
    6318358388
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    IMAT Conference & Expo


  • 2.  RE: Au thickfilm for hybrid circuits

    Posted 03-07-2023 11:31
    Gerard and co -

    I find some intriguing things in your posted image.
    Most importantly, your use of 15.01KV w/ the SE1 detector
    on a polished cross-section.  If you have a backscatter
    detector, then I strongly suggest that you use it.

    Also I suggest the excellent book by George Harman:
    Wire Bonding in Microelectronics, 3rd ed.

    regards,
    - Jim





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  • 3.  RE: Au thickfilm for hybrid circuits

    Posted 03-07-2023 13:05

    Thanks for the comment. I have used both SE and BSD detectors on this project. My main interest again are the particles in the Au thickfilm – should they be there?

     

    Regards

     

    Gerard




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  • 4.  RE: Au thickfilm for hybrid circuits

    Posted 03-08-2023 12:34
    Brian -

    I would expect the Bi/bismuth to be in the thick-film gold
    as bismuth oxides.  Hence, as particulates.  I would expect
    the Cd/cadmium to be alloyed with the Au/gold.

    regards,
    - Jim





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