Flip chip on circuit board with enhanced heat dissipation and method therefor
First Claim
1. A circuit board assembly comprising:
- a substrate having electrical conductors and a first thermal conductor layer on a first surface thereof and having a second thermal conductor layer on a second surface opposite the first surface;
a surface-mount IC device mounted to the first surface of the substrate, the surface-mount IC device having a first set of solder bumps registered with the electrical conductors and at least one solder bump registered with the first thermal conductor layer;
a via within the substrate between the first surface of the substrate and the second surface of the substrate;
a heat-conductive material within the via and contacting the first thermal conductor layer on the first surface of the substrate; and
a heatsink embedded within the substrate between the via and the second thermal conductor layer and contacting the heat-conductive material within the via, wherein heat is conducted from the surface-mount IC device to the second thermal conductor layer through the at least one solder bump, the first thermal conductor layer, the heat-conductive material within the via, and the heatsink.
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Accused Products
Abstract
A circuit structure and method for conducting heat from a power flip chip. Heat is dissipated from a flip chip mounted to a PCB by conducting heat through conductive vias to the opposite surface of the PCB. The flip chip is equipped with two sets of solder bumps, one of which is registered with conductors on the PCB, while the second is registered with a thermal conductor layer on the PCB surface and electrically isolated from the conductors. A second thermal conductor layer on the opposite surface of the PCB contacts the vials, such that heat is conducted from the flip chip to the second thermal conductor layer through the second set of solder bumps, the first thermal conductor layer, and the conductive vias. A heatsink is embedded in the PCB between the vias and the second thermal conductor layer to further promote heat conduction away from the flip chip. Heat can be conducted from the PCB with a second heatsink, such as a housing that encloses the PCB. The second heatsink either directly contacts the second thermal conductor layer, or makes thermal contact with the second thermal conductor layer through a thermally-conductive lubricant or adhesive.
120 Citations
20 Claims
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1. A circuit board assembly comprising:
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a substrate having electrical conductors and a first thermal conductor layer on a first surface thereof and having a second thermal conductor layer on a second surface opposite the first surface; a surface-mount IC device mounted to the first surface of the substrate, the surface-mount IC device having a first set of solder bumps registered with the electrical conductors and at least one solder bump registered with the first thermal conductor layer; a via within the substrate between the first surface of the substrate and the second surface of the substrate; a heat-conductive material within the via and contacting the first thermal conductor layer on the first surface of the substrate; and a heatsink embedded within the substrate between the via and the second thermal conductor layer and contacting the heat-conductive material within the via, wherein heat is conducted from the surface-mount IC device to the second thermal conductor layer through the at least one solder bump, the first thermal conductor layer, the heat-conductive material within the via, and the heatsink. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A circuit board assembly comprising:
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a printed circuit board having electrical conductors and a first thermal conductor layer on a first surface thereof and having a second thermal conductor layer on a second surface opposite the first surface, the electrical conductors defining a conductor pattern that surrounds the first thermal conductor layer on the first surface of the printed circuit board; a flip chip mounted to the printed circuit board, the flip chip having a first set of solder bumps registered with the electrical conductors and a second set of solder bumps registered with the first thermal conductor layer, the second set of solder bumps being located on the flip chip at an interior surface region thereof; vias within the printed circuit board between the first surface of the printed circuit board and the second surface of the printed circuit board; a heat-conductive material plated within the vias and contacting the first thermal conductor layer on the first surface of the printed circuit board; and a heatsink embedded within the printed circuit board between the vias and the second thermal conductor layer and contacting the heat-conductive material within the vias, wherein heat is conducted from the flip chip to the second thermal conductor layer through the second set of solder bumps, the first thermal conductor layer, the heat-conductive material within the vias, and the heatsink. - View Dependent Claims (9, 10, 11, 12)
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13. A method for forming circuit board assembly, the method comprising the steps of:
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providing a substrate having oppositely-disposed first and second surfaces, a heatsink embedded within the second surface, and a via within the substrate between the first and second surfaces; depositing a heat-conductive material within the via and forming electrical conductors and a first thermal conductor layer on the first surface of the substrate, the heat-conductive material contacting the first thermal conductor layer and the heatsink; forming a second thermal conductor layer on the second surface of the substrate, the second thermal conductor layer contacting the heatsink such that said heat sink is between the via and said second thermal conductor layer; and mounting a flip chip to the substrate, the flip chip having a first set of solder bumps registered with the electrical conductors and at least one solder bump registered with the first thermal conductor layer, wherein heat is conducted from the flip chip to the second thermal conductor layer through the at least one solder bump, the first thermal conductor layer, the heat-conductive material within the via, and the heatsink. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification