Conductive pedestal on pad for leadless chip carrier (LCC) standoff
AssigneeTexax Instruments Incorporated
InventorSteven O. Dunford
Life of this patent
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Abstract
A device and method for insuring the separation between a leadless chip carrier and printed wiring board, comprising aligning and attaching conductive pedestals to contact pads of either member and embedding the pedestals into the solder columns which are used to provide electrical connection. The conductive pedestals are comprised of an electrically conducting metal, solder, alloy or composite which will also provide thermal dissipation in selected designs.
Claims10
A device formed on selected contact pads to assure a controlled separation between a leadless chip carrier attached to a printed wiring board comprising:
- a) conductive pedestals located within selected contact pad areas, the number and distribution of pedestals being only sufficient to achieve coplanarity between said carrier and said board,
- b) said pedestals attached to said contact pads, and
- c) said pedestals wholly incorporated into the solder connection between carrier and wiring board.
A device formed on selected contact pads to assure a controlled separation between a leadless chip carrier attached to a printed wiring board comprising:
- a) conductive pedestals located within said selected contact pad areas,
- b) said pedestals attached to contact pads, and
- c) said pedestals incorporated into the solder connection between carrier and wiring board so that there is no loss of space of the board, and
- d) the volume of the conductive pedestal is small with respect to the solder connection so that it does not significantly alter the properties of said connection, and
- e) said conductive pedestals are of controlled size to meet specifications for separation height and,
- f) said conductive pedestals are of sufficiently uniform size, and only sufficient in number and location to maintain coplanarity specifications, and
- g) said conductive pedestals are comprised of a solder, metal or composite which is compatible with solder, and
- h) said conductive pedestals are sufficiently stable to maintain separation height within specifications after thermal exposure to solder reflow processing, and
- i) said conductive pedestals are attached to the contact pad area of either the leadless chip carrier or those of the printed wiring board.
Dependencies are inferred from the claim text.