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                   Wire bonding (from 6)


        Bond Parameters and Loop Geometry
        Once fixturing and tooling have been ad-
        dressed, wire bond development can be-
        gin.


        A robust wire bond weld is developed us-
        ing a very specific design-of-experiments
        (DOE) for selection of critical bond param-
        eters.


        The three main bond parameters that
        need to be optimized are force, power, and
        time. These three parameters are interde-
        pendent and typically require a full facto-
        rial DOE to resolve them properly.


        Wire bond parameters need to be devel-
        oped for a given part on both the source
        and destination bonds.




        Loop optimization
        Loop optimization is a separate issue and
        requires an understanding of the product
        geometry limitations and the environment
        in which it will be used.


        Parts that have unique geometries may
        present product limitations over life. If
        bond wires are too long they can fail in
        thermal stress. Next page























                  Wire bond failure from vibration
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