Surface mount stress relief hidden lead package device and method
November 29, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3588616 3762040 Method of providing spacers on an insulating substrate Printed circiuit board Adapting contacts for connection thereto Low stress leadless chip carrier and method of assembly Mounting system for stress relief in surface mounted components Compliant interconnection and method therefor Printed wiring board with zones of controlled thermal coefficient of expansion Compliant layer printed circuit board InventorAssigneeApplicationNo. 346131 filed on 11/29/1994US Classes:228/180.22, Lead-less (or "bumped") device228/103, With measuring, testing, indicating, inspecting, or illuminating228/175Plural diverse bondingExaminersPrimary: Heinrich, Samuel M.Attorney, Agent or FirmInternational ClassH05K 003/34AbstractA hidden lead package device is configured to be placed between a leadless component such as a surface mount package (SMP) used to house a SAW device and a standard printed circuit board configured for solder joints in a leadless contact with the printed circuit board. The hidden lead device is made using materials having similar characteristic thermal expansion properties as that of the SMP and printed circuit board pads to which the hidden lead is affixed. The hidden lead extends across the underside of the SMP along the PCB surface. One end of the lead is brazed to an SMP pad and the opposite end is soldered to a communicating PCB pad. The brazing temperature is higher than the reflow temperature for the solder. The hidden lead device causes the relative movement between the leadless carrier and the printed circuit board to occur along a length of the hidden lead and thus minimizes tensional or compressive forces to the solder joints. Such an approach relieves the stress and resulting creep typically seen at solder joints when mounting leadless packages to printed circuit boards. In addition, by segregating the input and output pads and placing the hidden leads to ground pads between those of input and output pads, crosstalk rejection of the components is improved.Other References
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