| 摘要 |
An electronic device or flip chip includes a chip having an active side and an opposed side, with the active side electrically connected by bumps with the top of a substrate. A first material or underfill, generally located between the chip and the substrate, is resistive to electrical conductivity to isolate the flip chip bumps and their contacts. A second electrically conductive material is formed on a portion of the top of the substrate, the opposed side of the chip and over the first material to completely cover and protect the opposed side. The second material preferably has 80-95% metal fillers and is at least 75 microns (0.075 millimeters) thick. The second thermally/electrically conductive material transfers heat from the opposed or back side of the chip to provide a low cost flip chip package with comparable thermal performance to a flip chip with a heat spreader and a stiffener. Savings in cost of materials and processing is achieved by the elimination of at least the heat spreader and, when desired, the stiffener.
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