# US 2009/0260778 A1 · Low profile heat sink for semiconductor devices

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- Number: US 2009/0260778 A1
- Document ID: US20090260778A1
- Status: Published application
- Kind: A1
- Application number: 12/105,478
- Filed: 2008-04-18
- Published: 2009-10-22
- Earliest claimed: 2008-04-18
- Assignees: International Business Machines Corporation
- Inventors: Stephen P. Ayotte; David J. Hill; Kristen L. Holverson; Christina M. Pepi; Timothy M. Sullivan
- Web page: https://patentgrep.com/patent/US20090260778A1

## CPC

- H10W 40/43: by flowing gases, e.g. forced air cooling
- G06F 1/20: Cooling means
- H10W 40/22: characterised by their shape, e.g. having conical or cylindrical projections
- F28F 3/02: Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations (F28F3/08 takes precedence)
- F28F 13/06: by affecting the pattern of flow of the heat-exchange media {(F28F13/003 takes precedence; static flow control means in header boxes F28F9/026)}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)

## Abstract

A heat sink for cooling a heat-generating device includes a base and a cooling section coupled thereto for cooling the device. The cooling section includes a plurality of flow tubes, each flow tube having an inlet, an outlet, and a bounding wall that defines a closed fluid flow path from the inlet to the outlet. Each of the flow tubes includes a central axis that is substantially parallel to a reference plane of the heat-generating device. The flow tubes may be arranged in a layered stack and include a bounding wall that has a thickness that decreases with increasing distance in the layered stack. The flow tubes may also include a cross-sectional area that decreases with increasing distance in the layered stack. Furthermore, the bounding wall of the flow tubes may have a non-planar configuration in a direction generally parallel to the central axis.

## Claims

### Claim 1

A heat sink for cooling a heat-generating device including a reference plane, comprising:
a base for mounting to the heat-generating device; and
a cooling section coupled to the base, the cooling section including a plurality of flow tubes, each flow tube having an inlet, an outlet, and a bounding wall that defines a closed fluid flow path from the inlet to the outlet, and each flow tube including a central axis along which fluid flows that is substantially parallel to the reference plane of the heat-generating device.

### Claim 2 (depends on 1)

The heat sink of claim 1, wherein the bounding wall of each flow tube has a geometrical shape viewed along the central axis selected from the group consisting of triangular, rectangular, square, pentagonal, octagonal, and circular.

### Claim 3 (depends on 1)

The heat sink of claim 1, wherein the flow tubes are arranged in a layered stack and the bounding wall of each flow tube has a thickness that decreases with increasing distance of the flow tube in the layered stack.

### Claim 4 (depends on 1)

The heat sink of claim 1, wherein the flow tubes are arranged in a layered stack and each flow tube includes a cross-sectional area that decreases with increasing distance of the flow tube in the layered stack.

### Claim 5 (depends on 1)

The heat sink of claim 1, wherein the bounding wall of each flow tubes is non-planar in a direction generally parallel to the central axis.

### Claim 6 (depends on 5)

The heat sink of claim 5, wherein the bounding wall of each flow tube has a topography in the direction generally parallel to the central axis selected from the group consisting of sawtooth, step shaped, and sinusoidal.

### Claim 7

An apparatus, comprising:
a microprocessor including an outer surface defining a reference plane; and
a heat sink including a base coupled to the outer surface of the microprocessor, and a cooling section coupled to and extending from the base and including a plurality of flow tubes, each flow tube having an inlet, an outlet, and a bounding wall that defines a closed fluid flow path from the inlet to the outlet and having a central axis,
wherein the flow tubes are arranged in a layered stack and the bounding wall of each flow tube has a thickness that decreases with increasing distance of the flow tube in the layered stack and is non-planar in a direction generally parallel to the central axis, and
wherein each flow tube includes a cross-sectional area that decreases with increasing distance of the flow tube in the layered stack.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the bounding wall of each flow tube has a topography in the direction generally parallel to the central axis selected from the group consisting of sawtooth, step shaped, and sinusoidal.

### Claim 9 (depends on 7)

The heat sink of claim 7, wherein the central axis of each flow tube is generally parallel to the reference plane of the microprocessor.