Patent Application
20080013281
a illustrates vapor exiting a wick structure.
b illustrates vapor condensing onto a wick structure.
a illustrates several diamond pins centrally inserted into a lid.
b illustrates the underside of
a illustrates one embodiment of a configurable diamond pin.
b illustrates the embodiment of a configurable diamond pin in
c illustrates a second embodiment of a configurable diamond pin.
Embodiments of the present invention will be explained in detail below with reference to the figures. Like elements are denoted by like reference numbers throughout the figures.
Within a single silicon microprocessor chip, there are many high power compact circuit blocks, with different power levels depending on their application. The “junction temperature” is defined as the highest temperature on the silicon microprocessor chip, and is generally located at the position where many high power circuit blocks meet.
In one or more embodiments, the two aforementioned cooling methodologies, i.e., cooling with diamond material and cooling with heat pipes, are employed to lower temperatures on a silicon microprocessor. Furthermore, these two cooling methods may be combined with a heat sink structure to cool silicon microprocessors.
In one embodiment, as shown in
A silicon microprocessor (10) is fixed between a substrate layer (12) and a first thermal interface material (TIM) layer (14). A lid (18) encases the silicon microprocessor (10), abutting the first TIM layer (14), and fixed to the top of the substrate layer (12). Applied to the top of the lid is a second TIM layer (16). One or more configurable diamond pins (40), here configured as straight pin-like structures, traverse the second TIM layer (16) and holes drilled through the lid (18). The bottom ends of the diamond pins (40) abut the first TIM layer (14). The top ends of the diamond pins (40) are fixed to base of the heat pipes (36). The heat pipes (36) are centrally located, surrounded by and connected to a heat sink structure (42). In the embodiment shown, two heat pipes and two diamond pins are centrally located. However, one skilled in the art will appreciate that the number of heat pipes or diamond pins used and the locations of the heat pipes or diamond pins may be configured differently based on the layout of, and accordingly hot spots of, the silicon microprocessor.
The lid (18) covers the microprocessor to provide protection and ensure reliability. However the lid (18) inhibits heat from transferring out. In the prior art, heat transfers from the silicon microprocessor (10) to the first TIM layer (14) to the lid (18) to the second TIM layer (16), and then to the heat sink fins (20). In one or more embodiments, heat still transfers in this manner, however, additionally heat travels more so from the silicon microprocessor (10) to the first TIM layer (14) to diamond pins (40) to heat pipes (36), and then to the heat sink structure (42). Connecting the diamond pins (40) to the base of the heat pipes (36), and connecting the heat pipes (36) securely to the heat sink structure (42) ensures an even and high heat transfer from junction temperature hot spots on the silicon microprocessor. From the heat sink structure the heat is dispersed through the large surface area provided by a plurality of heat sink fins (41). One skilled in the art will appreciate that, in one or more embodiments, diamond pins abut areas of less critical temperatures on the silicon microprocessor, or that diamond pins may transfer heat directly to a heat sink structure, bypassing heat pipes.
Diamond pins are rather expensive due to their high conductivity and other physical properties, thus, in one or more embodiments, the use of diamond pins is preferably used to conduct heat away from critical hot spots on the silicon microprocessor that dissipate junction temperatures. The locations of the junction temperature hot spots may vary on the microprocessor chip, so in order to maintain flexibility, the diamond pins can be configured in shape to abut hot spots while still fixed to the preferably centrally located heat pipes.
Further,
In the embodiments illustrated in
Embodiments may include one or more of the following advantages. Namely, the short, small design of configurable diamond pins reduces costs as opposed to an expensive system only using diamond pins. Furthermore, the small configurable diamond pins are flexible in placement, when the placement of the heat sink structure may be rigid and fixed. The diamond pins efficiently transfer heat to the heat pipes, which having a high heat transfer rate, then fan out the heat across the fins of the heat sink structure. Embodiments shown provide cooling to the silicon microprocessor chip at specific locations and as a whole. Additionally, placing the diamond pins over the junction temperatures hot spot locations reduces junction temperature and ensures functionally at critical circuit blocks in the silicon microprocessor.
In one or more embodiments, passive elements are employed to ensure reliability in cooling the silicon microprocessor. Furthermore, embodiments provide a cost efficient and highly effective method of cooling a silicon microprocessor. Passive cooling allows for fewer fans or decreased fan speed, providing savings in cost, physical dimensions, and power consumption. The combination of the dual methodologies, heat pipe and diamond cooling, makes for a robust design. Traditional designs with only heat pipes or only diamond pins would make the cooling apparatus resultantly cumbersome or expensive respectively.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
