In-line memory module cooling system

A system to aid in cooling an in-line memory module may include a thermal interface material adjacent the in-line memory module. The system may also include a heat spreader adjacent the thermal interface material. The system may further include a cold-plate adjacent the heat spreader, the cold-plate, heat spreader, and thermal interface material to aid in cooling the in-line memory module.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the field of computer systems, and, more particularly, to a system to cool an in-line memory module.

2. Description of Background

Generally, an in-line memory module is a printed circuit board that may carry random access memory (“RAM”), application-specific integrated circuits (“ASIC”), surface mount components (“SMC”), electrical contacts, and/or the like. The in-line memory module usually plugs into another printed circuit board carrying additional electronic components.

A heat spreader is a component that may efficiently transfer heat from one area to another area. The heat spreader usually has high thermal conductivity.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, a system to aid in cooling an in-line memory module may include a thermal interface material adjacent the in-line memory module. The system may also include a heat spreader adjacent the thermal interface material. The system may further include a cold-plate adjacent the heat spreader, and the cold-plate, heat spreader, and thermal interface material to aid in cooling the in-line memory module.

The cold-plate may include an enclosed fluid pathway. The cold-plate may be joined to the heat spreader. The cold-plate may be joined to the heat spreader by filler metal joinery and/or curable materials.

The cold-plate may be joined to an end of the heat spreader. The cold-plate joined to the heat spreader does not prevent the in-line memory module from being removed.

The thermal interface material may include a conformal material. The conformal material may include a thermal pad, a thermal pad with a non-stick surface, and/or thermal paste. The in-line memory module may be fully buffered.

In one embodiment, the system may include thermal interface material adjacent both sides of an in-line memory module. The system may further include heat spreaders adjacent both thermal interface materials. The system may additionally include a cold-plate adjacent both heat spreaders, and the cold-plate, heat spreaders, and thermal interface materials to aid in cooling the in-line memory module.

The cold-plate may include an enclosed fluid pathway joined to at least one of the heat spreaders. The cold-plate may be joined to the ends of at least one of the heat spreaders. The cold-plate joined to at least one of the heat spreaders does not prevent the in-line memory module from being removed.

In one embodiment, the system may include thermal interface material adjacent both sides of a first in-line memory module, and heat spreaders adjacent the thermal interface materials. The system may also include other thermal interface material adjacent both sides of a second in-line memory module, and additional heat spreaders adjacent the other thermal interface materials. The system may further include a conduction bar adjacent one of the heat spreaders and one of the additional heat spreaders, and the conduction bar between the first in-line memory module and the second in-line memory module. The system may additionally include a cold-plate adjacent the conduction bar, and the cold-plate, all heat spreaders, conduction bar, and all thermal interface materials to aid in cooling the first and second in-line memory modules.

The cold-plate may include an enclosed fluid pathway joined to the conduction bar and/or at least one of all heat spreaders. The cold-plate may include a pump to circulate fluid through the enclosed fluid pathway.

The cold-plate may be joined to the conduction bar and/or at least one of all heat spreaders by filler metal joinery and/or curable materials. The cold-plate may be joined to the conduction bar and/or the ends of at least one of all heat spreaders. The cold-plate joined to the conduction bar and/or the ends of at least one of all heat spreaders does not prevent any of the in-line memory modules from being removed.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. Like numbers refer to like elements throughout, like numbers with letter suffixes are used to identify similar parts in a single embodiment, letter suffix lower case n is a variable that indicates an unlimited number of similar elements, and prime notations are used to indicate similar elements in alternative embodiments.

It should be noted that in some alternative implementations, the functions noted in a flowchart block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

With reference now toFIGS. 1-4, a system10to aid in cooling an in-line memory module12a-12nis initially described. According to one embodiment of the invention, the system10includes a thermal interface material14a-14nadjacent the in-line memory module12. In one embodiment, the system10also includes a heat spreader16a-16nadjacent the thermal interface material14a-14n. In another embodiment, the system10further includes a cold-plate18a-18nadjacent the heat spreader16a-16n, and the cold-plate18a-18n, heat spreader16a-16n, and thermal interface material to aid in cooling the in-line memory module12a-12n.

In one embodiment, the cold-plate18a-18nis an enclosed fluid pathway. In another embodiment, the cold-plate18a-18nis joined to the heat spreader16a-16n. In another embodiment, the cold-plate18a-18nis joined to the heat spreader16a-16nby filler metal joinery and/or curable materials.

In one embodiment, the cold-plate18a-18nis joined to an end of the heat spreader16a-16n. In another embodiment, the cold-plate18a-18njoined to the heat spreader16a-16ndoes not prevent the in-line memory module12a-12nfrom being removed.

In one embodiment, the thermal interface material14a-14nincludes a conformal material. In another embodiment, the conformal material includes a thermal pad, a thermal pad with a non-stick surface, and/or thermal paste. In another embodiment, the in-line memory module12a-12nis fully buffered.

In one embodiment, the system10includes thermal interface material14a-14nadjacent both sides of an in-line memory module12a-12n. In another embodiment, the system10further includes heat spreaders16a-16nadjacent both thermal interface materials14a-14n. In another embodiment, the system10additionally includes a cold-plate18a-18nadjacent both heat spreaders14a-14n, and the cold-plate18a-18n, heat spreaders16a-16n, and thermal interface materials14a-14nto aid in cooling the in-line memory module12a-12n.

In one embodiment, the cold-plate18a-18nincludes an enclosed fluid pathway joined to at least one of the heat spreaders16a-16n. In another embodiment, the cold-plate18a-18nis joined to the ends of at least one of the heat spreaders16a-16n. In another embodiment, the cold-plate18a-18njoined to at least one of the heat spreaders16a-16ndoes not prevent the in-line memory module12a-12nfrom being removed.

In one embodiment, the system10includes thermal interface material14a-14badjacent both sides of a first in-line memory module12a, and heat spreaders16a-16badjacent the thermal interface materials. In another embodiment, the system10also includes other thermal interface material14a-14badjacent both sides of a second in-line memory module12n, and additional heat spreaders16c-16nadjacent the other thermal interface materials14c-14n. In one embodiment, the system10further includes a conduction bar20adjacent one of the heat spreaders14a-14band one of the additional heat spreaders14c-14n, and the conduction bar20between the first in-line memory module12aand the second in-line memory module12n. In another embodiment, the system10additionally includes a cold-plate18a-18nadjacent the conduction bar20, and the cold-plate, all heat spreaders16a-16n, conduction bar, and all thermal interface materials14a-14nto aid in cooling the first and second in-line memory modules12n.

In one embodiment, the cold-plate18a-18nincludes an enclosed fluid pathway joined to the conduction bar20and/or at least one of all heat spreaders16a-16n. In another embodiment, the cold-plate18a-18nincludes a pump24to circulate fluid through the enclosed fluid pathway.

In one embodiment, the cold-plate18a-18nis joined to the conduction bar18a-18nand/or at least one of all heat spreaders16a-16nby filler metal joinery and/or curable materials. In another embodiment, the cold-plate18a-18nis joined to the conduction bar20and/or the ends of at least one of all heat spreaders16a-16n. In another embodiment, the cold-plate18a-18njoined to the conduction bar20and/or the ends of at least one of all heat spreaders16a-16ndoes not prevent any of the in-line memory modules12a-12nfrom being removed.

In view of the foregoing, the system10aids in cooling an in-line memory module12a-12n. As a result, the system10improves signal integrity of high-speed signals by reducing the impedance discontinuity between the ball grid array and ball grid array pads, for example.

In one embodiment, the problem solved is how to cool 50 to 150 watt buffered Memory dual in-line memory modules (“DIMMs”)12a-12non tight pitches. Currently DIMMs are air cooled individually. Limitations of air cooling are in the 10 to 30 watt range.

In one embodiment, system10provides a practical means to water cool fully buffered DIMMs12a-12nplaced on a tight pitch. In another embodiment, the system10provides a “water coolable DIMM package” (or WDP) by sandwiching a DIMM between conformal pads, e.g. thermal interface material14a-14n, and/or thermal grease. In another embodiment, the system10is then sandwiched between two flat plates, e.g. heat spreader16a-16n, typically copper or aluminum. The exposed surfaces of these two metal plates become the heat transfer surfaces for heat generated internal to the DIMM12a-12n.

In one embodiment, the system10provides a coldplate18a-18nconsisting of two rectangular brazed coldplates running perpendicular to and just outside the DIMMs12a-12n. In another embodiment, copper or aluminum plates16a-16nare placed between each DIMM12a-12n.

In one embodiment, these plates16a-16nare attached to the coldplates18a-18non each end of the DIMMs12a-12nvia either soldering or thermal epoxy. In another embodiment, water is run through the two coldplates18a-18non each end.

In one embodiment, the heat in the DIMMs12a-12nis conducted out through the thermal surfaces of the WDP. In another embodiment, a thin layer of conformal material14a-14nsuch as a thermal pad with non-stick surface and/or thermal paste is placed between the WDP and the conduction plates16a-16nthat run parallel and adjacent to each DIMM12a-12n. These plates16a-16nconduct the heat to the coldplates18a-18non each end.

The system10provides an easy and compact means to water cool densely DIMMs12a-12n. The system10also provides the capability to plug and unplug each DIMM12a-12nin a very standard manner, despite being water cooled. For example, the system10provides the capability to service individual DIMMs12a-12nin the field without breaking water lines. In other words, the system10is serviced like standard DIMMs12a-12nin that the DIMM is removed by itself and not the coldplate18a-18n.

In one embodiment, the thermal interface material14a-14n, e.g. thermagap conformal pads, account for misalignment and compliance. In another embodiment, the WDP width is 0.3 mm wider than stationary conduction plates gap.

In one embodiment, the top copper plate16a-16nis ½ to 1 mm thick. In another embodiment, two smaller plates16a-16nare provided over the dynamic random access memory.

In one embodiment, the lower copper plate16a-16nattached to an uncompressed conformal pad14a-14n. In another embodiment, in the process of inserting the WDP between water cooled plates16a-16n, misalignments and tolerances can be eliminated via the conformance of a chomerics pad14a-14n. In another embodiment, the heat spreader16a-16nincludes a central 0.15 mm recess in the copper plates to capture paste14a-14non DIMM12a-12ninsertion and extraction.

In one embodiment, the conduction bar20is soldered to the coldplates18a-18n. In another embodiment, between and parallel to each DIMM12a-12nrow have a thick copper plate20. In another embodiment, each ends of the conduction bar20are brazed to coldplates18a-18nthat run perpendicular to DIMMs12a-12n. In another embodiment, alignment pins in the board assures proper location of coldplate assembly18a-18nto the WDPs.

FIG. 5is a diagram of 3 DIMM's with a coldplate system as used in another embodiment.FIG. 6is a cross-sectional view diagram of a DIMM package with conduction plate embodiment.FIG. 7illustrates experimental results of cold plate temperatures in one embodiment of the invention.