An apparatus including a micropin thermal solution is described. The apparatus comprises a substrate and a number of micropins thermally coupled to the substrate.

TECHNICAL FIELD

The invention generally relates to cooling electronic apparatuses and systems, and in particular, but not exclusively relates to micro-cooling technology.

BACKGROUND INFORMATION

As electronic devices become more powerful and smaller (i.e., more densely packed), the power consumed by these electronic devices can result in a large amount of generated heat. The heat generated by these electronic devices may be detrimental to the operation of the electronic devices. Accordingly, a common concern associated with electronic components is heat removal.

For example, an electronic device may include an integrated circuit (IC) die. A thermal solution may be thermally coupled to the IC die to facilitate dissipation of heat from the IC die. Commonly, the thermal solution may be in the form of a heat sink having a number of fins or channels (i.e., a passive solution). As air passes by the fins or channels, heat may be transferred from the IC die to the surrounding air via the fins or channels. However, utilizing fins or channels does not provide efficient and uniform removal of heat from the IC die due to various effects such as, but not limited to, variations of heat generation from different areas on the IC die or the inability to transfer heat to a location, which is remote from the IC die.

DETAILED DESCRIPTION

In various embodiments, an apparatus including a micropin thermal solution is described. In the following description, various embodiments will be described. However, one skilled in the relevant art will recognize that the various embodiments may be practiced without one or more of the specific details, or with other methods, materials, components, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Similarly, for purposes of explanation, specific numbers, materials and configurations are set forth in order to provide a thorough understanding of the invention. Nevertheless, the invention may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the invention. Furthermore, it is understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

FIGS. 1a-1billustrate an apparatus having a micropin thermal solution, in accordance with one embodiment of the invention. Illustrated inFIG. 1ais a side like view of an apparatus100. InFIG. 1a, the apparatus100includes a substrate102and a number of micropins104.FIG. 1billustrates a top like view of the apparatus100. Accordingly, as shown inFIG. 1b, the micropins104are arranged in a pixel like pattern over the substrate102, in accordance with various embodiments of the invention.

Referring toFIG. 1b, the micropins104may be arranged to provide a predetermined space between the micropins104. As will be described in more detail, the predetermined space may be based at least in part on the material that flows through the space such as, but not limited to water, glycol, oil, other liquids including alcohol that is in liquid form. Further, the micropins104arranged in the pixel like pattern shown inFIG. 1bfacilitates flow of material in all directions such as, but not limited to, at least two directions (e.g., the x-direction and the y-direction) as viewed inFIG. 1b. Of course in other embodiments of the invention the micropins or pins could be staggered. In other embodiments the pins or micropins could be set in rows. Other patterns of pins or micropins are also contemplated.

In the illustrated embodiment shown inFIG. 1a, the micropins104may be formed from the substrate102. That is, various etching methods may be utilized to form the micropins104from the substrate102such as, but not limited to, deep reactive ion etching (DRIE), wet etching, micromachining, and the like. Accordingly, the micropins104may be made of a semiconductor material, such as but not limited to silicon. Alternatively, the micropins104may be formed and disposed on the substrate102. That is, the micropins104may be made of a variety of materials and methods such as, but not limited to, metals (e.g., copper) and micromachining methods, and subsequently disposed on the substrate. Additionally, the substrate102may be an integrated circuit (IC) die. Alternatively, the substrate102may be thermally coupled to an IC die.

The thermal energy (i.e., heat) from the substrate may be transferred to the micropins104. Because in one embodiment, the micropins104are formed on the substrate102, the micropins104may be thermally coupled to the IC die, and in turn, the micropins104facilitate transfer of heat to the material in substantial contact with the micropins104. Alternatively, the micropins104may be thermally coupled to the substrate, which in turn, may be thermally coupled to an IC die. That is, effectively, the micropins104are thermally coupled to the IC die when attaching the pin grid device to the back of an IC die. The back of the IC die may be thinned by grinding, lapping and/or polishing, to reduce the thermal resistance between the front of the die where heat is generated and the pin grid device, and improve the heat removing capabilities of the pin-grid device.

FIG. 2illustrate a method of forming micropins, in accordance with one embodiment. Shown inFIG. 2is a side like view of a substrate202. The substrate202may be made of a suitable material to facilitate heat transfer such as, but not limited to, silicon based material, and a metal based material (e.g., silicon, copper, etc.). Various etching methods may be applied to the substrate202such as, but not limited to, DRIE, wet etching, micromachining, and so forth. As a result of the etching process, a number of micropins204may be formed from the substrate202.

In the illustrated embodiment, formed along with the micropins204may be a side wall206. As will be described in further detail, in various embodiments, the side wall206facilitates substantial enclosure of the micropins204within a device to facilitate heat removal from an integrated circuit (IC) die, and a cover may further facilitate the enclosure of the micropins204.

FIG. 3illustrates an apparatus having a micropin thermal solution, in accordance with an alternate embodiment. InFIG. 3, a side like view is illustrated of an apparatus300. The apparatus300includes a substrate302and a number of micropins304similar to the apparatus100shown inFIG. 1a-1b. However, illustrated inFIG. 3, the apparatus300includes an interface layer306disposed between the micropins304and the substrate302.

In accordance with one embodiment, the interface layer306may be of a material to provide structural support for the micropins304and facilitate thermal coupling such as, but not limited to, a diamond film. As previously described, the micropins304may be made of a semiconductor material, and accordingly, the interface layer may provide structural support for the micropins304and facilitate thermal coupling (i.e., heat transfer) from the substrate302to the micropins304. Here again, the substrate may be an IC die or a substrate that may be thermally coupled to an IC die.

In one embodiment, the interface layer306may be made of a solderable material having various thermal properties such as, but not limited to, copper (Cu), gold (Au), nickel (Ni), aluminum (Al), titanium (Ti), tantalum (Ta), silver (Ag), Platinum (Pt), Tin (Sn), Lead (Pb) and any combination thereof. Accordingly, in one embodiment, the micropins304may be made of a metal material such as, but not limited to, copper.

Continuing to refer toFIG. 3, it should be appreciated by those skilled in the relevant art that in addition to the interface material306, various adhesive materials (not shown) may be utilized between the micropins304and the substrate302.

FIG. 4illustrates an apparatus having a micropin thermal solution, in accordance with another embodiment. Illustrated inFIG. 4, is a cross-sectional type view of an apparatus having a device400. The device400includes substrate402and a number of micropins404. As shown in the embodiment, the substrate402provides a bottom of the device400. Additionally, the device400includes a wall406that substantially surround the micropins404. Further, a cover408disposed over the micropins404results in the micropins404being substantially enclosed in the device400.

The micropins404and the side wall406may both be formed from the substrate402as previously described inFIG. 2. The cover408may be attached to the micropins404by various attachment methods such as but not limited to, solder, adhesive, anodic bonding, thermal compression bonding, and so forth. Additionally, the cover may be made of various materials such as, but not limited to, acrylic based material (e.g., Plexiglas® from Rohm & Haas Corporation of Philadelphia, Pa.).

The device400has an inlet410and an outlet412. As will be described in detail, the inlet410and the outlet412facilitates flow of material through the micropins404. Additionally, inFIG. 4, an interface layer414is shown between the cover406and the micropins404. The interface layer414may be any type of layer that facilitates a seal between the cover406and the micropins404. Accordingly, the interface layer414may be of a solderable material, adhesive material, or any combination thereof.

FIG. 5illustrates an apparatus having a micropin thermal solution, in accordance with another embodiment. Illustrated inFIG. 5, is a cross-sectional type view of an apparatus having a device500. The device500includes a substrate502and a number of micropins504. As shown in the embodiment, the substrate502provides a bottom of the device500. Additionally, the device500includes a wall506that substantially surround the micropins504similar to the device400shown inFIG. 4. However, in the embodiment illustrated inFIG. 5, a cover508has the micropins504formed on the cover508. Here again, the micropins504are substantially enclosed in the device500.

The device500has an inlet510and an outlet512. As will be described in detail, the inlet510and the outlet512facilitates flow of material through the micropins504. Additionally, inFIG. 5, an interface layer514is shown between the micropins504and the substrate502. The interface layer514may be any type of layer that facilitates a seal between the micropins504and the substrate502. Accordingly, the interface layer514may be of a solderable material, adhesive material, or any combination thereof.

As previously alluded to, the cover508having the micropins504may be of any material such as, but not limited to, silicon and metal. Additionally, in the illustrated embodiment, the cover508, having the micropins504, may be formed as described inFIG. 2(i.e., various etching methods).

InFIGS. 1-5, the number of micropins may be arranged in the pixel like pattern as shown inFIG. 1b. Additionally, as previously described, the substrate may be an IC die. Alternatively, the substrate may be a substrate that is thermally coupled to an IC die. It should be appreciated by those skilled in the art that the substrate and the micropins may be thermally coupled via various thermal interface materials (TIMs).

In one embodiment, each of the micropins may have the following approximate overall dimensions: 50 microns in width, 50 microns in thickness, and a height of 300 microns. The micropins width can range from 10-250 microns, the thickness can range from 10-250 microns and the thickness can be in the range of 10-500 microns. Referring toFIG. 1b, in one example arrangement, the pitch may be approximately 50 microns and the substrate may have approximate dimensions of 1 centimeter by 1 centimeter. The pins could be placed on larger or smaller substrates. Accordingly, in the example arrangement, the number of pins may be approximately 10000 micropins. The pitch of the pins can be in the range of 25-500 microns.

Various thermal and mechanical considerations may have an effect on the material utilized for the interface layer and/or the adhesive layer (not shown). For example, thermal considerations may include the coefficient of thermal expansion (CTE) considerations, thermal conductivity, and the like. Some mechanical considerations may include toughness, strength, and the like. Further, in various embodiments, the micropins104may be of any type of shape such as, but not limited to, a primitive geometric shape and a complex geometric shape. For example the micropins104may be cylindrical, rectangular, etc. including shapes without symmetry.

FIGS. 6a-6billustrate an apparatus having a micropin thermal solution, in accordance with various embodiments. Illustrated inFIG. 6ais a cross-sectional type view of an electronic system600having apparatuses that may be representative of the apparatuses shown inFIGS. 1-5having micropins602. The electronic system600is shown having the micropins602disposed directly on top of an IC die604(i.e., the micropins602are thermally coupled to the IC die604). The IC die604may be electrically coupled to a substrate606via a number of solder bumps608. The substrate606may be electrically coupled to a wiring board610via solder balls612. Accordingly, heat generated by the IC die604may be transferred to the micropins602.

Turning now toFIG. 6b, shown inFIG. 6bis a cross-sectional type view of an electronic system620having apparatus620that may be representative of the apparatuses shown inFIGS. 1-5having micropins602. InFIG. 6b, the micropins602are shown thermally coupled to a substrate622, which in turn may be thermally coupled to an IC die624. Shown inFIG. 6b, an interface layer626may be disposed between the substrate622and the IC die624. As previously alluded to, the interface layer626may be a TIM that facilitates thermal coupling of the substrate622with the IC die626, thereby facilitating heat transfer from the IC die626to the micropins602.

Continuing to refer toFIG. 6b, the apparatus620is shown thermally coupled to the IC die622. The IC die may be electrically coupled to the substrate606via solder bumps608. The substrate606may be electrically coupled to the wiring board610via solder balls612. Here again, the heat generated by the IC die622may be transferred to the micropins602because effectively, the micropins602may be thermally coupled to the IC die622.

Shown inFIGS. 6a-6b, the micropins602are substantially enclosed in the device600&620. However, as described previously, the micropins602need not be substantially enclosed (seeFIGS. 1-3). Additionally, in various embodiments, the wiring board610may have various devices electrically coupled to it such as, but not limited to a memory device (e.g., a flash memory device).

FIGS. 7a-7billustrate a micropin thermal solution, in accordance with various embodiments. Illustrated inFIG. 7ais a top like view of an apparatus700that may be representative of the apparatuses shown inFIGS. 4-6. Accordingly, the apparatus has the number of micropins404&504substantially enclosed the device400&500. Additionally, the device400&500has the inlet410&510and the outlet412&512. As shown, the micropins404&504are arranged in the pixel like pattern as previously described.

Referring now toFIG. 7b, the apparatus700may be included in a heat exchange system. Shown inFIG. 7bis a simplified view of a heat exchange system720. The heat exchange system720includes the apparatus700, a pump722, and a heat exchanger724.

As previously described, the apparatus700has the inlet410&510and the outlet412&512. The pump722has an inlet726and an outlet728. The heat exchanger724has an inlet730and an outlet732. As shown inFIG. 7, the outlet of the pump728may be coupled to the inlet410&510of the apparatus700(i.e., device) to facilitate transfer of material (i.e., material transferably coupled). The inlet726of the pump728may be material transferably coupled to the outlet732of the heat exchanger724. The outlet412&512may be material transferably coupled to the inlet730of the heat exchanger724.

As shown inFIG. 7b, a material such as, but not limited to, liquid water may be pumped to the apparatus700. The micropins, being thermally coupled to an IC die, facilitate heat transfer to the liquid water. As more heat is transferred to the liquid water, the liquid water may become steam. Further, as varying areas of the IC die generate varying amounts of heat, utilization of micropins and the manner in which the micropins are arranged facilitates uniform cooling of the IC die.

The pump722and the heat exchanger724may be any type of pump and heat exchanger such as, but not limited to, an electroosmotic pump. Additionally, the material utilized for the heat exchange system720may be any material such as, but not limited to, fluid, gas, and nanoparticles.

In the illustrated embodiment ofFIG. 7b, the pump722provides material to the apparatus700. The apparatus facilitates removal of heat from an IC die, as previously described. The heat exchanger724receives the heated material and removes the heat to the surrounding environment. A fan may be used to assist in the flow of air over the heat exchanger in order to facilitate the transfer of heat from the heat exchanger to the surrounding environment. It should be appreciated that in order not to obscure the embodiments of the invention, various components of the heat exchange system720are not shown. For example, there may various valves, seals, and so forth.

FIGS. 8-13illustrate various cross-sectional views of a micropin, thermal solution, in accordance with an embodiment of the invention.FIG. 8illustrates a cross-sectional view of a micropin or pin800in accordance with one embodiment of the invention.FIG. 8shows one pin800positioned within the flow of a fluid. The direction of the fluid flow is depicted by the arrow810. As discussed above, the fluid is also capable of flowing in a secondary direction, such as the direction depicted by arrow820. The cross-sectional shape of the pin800is substantially square. The pin800has a first side801and a second side802. Each of the first side801and the second side802has a dimension, a. According to an embodiment of the invention, the dimension a is in the range of 10 microns to 1,000 microns.

FIG. 9illustrates the cross-sectional view of a micropin or pin900, thermal solution, in accordance with another embodiment of the invention. The micropin or pin900includes a first side901and a second side902. The side901has a dimension labeled a, while the second side902has a dimension depicted by b. The cross-sectional area of the pin900is substantially rectangular in shape and therefore the dimension a does not equal the dimension b. The dimensions for a and b are within the range of 10 microns to 1,000 microns. The pin900is also positioned within a primary flow, having a direction depicted by an arrow910. As shown inFIG. 9, a fluid flowing in the direction910directly impacts a flat surface. Alternatively, the flat surface is substantially perpendicular to the flow direction910.

FIG. 10is a cross-sectional view of a micropin thermal solution or pin1000, in accordance with yet another embodiment of the invention. Pin1000has a side1001and a side1002. The side1001has a dimension a and the side1002has a dimension depicted by a. Therefore, the pin1000is substantially square. The pin1000is positioned within a flow having a primary direction depicted by the arrow having the reference numeral1010. The main difference between the pin1000and the pin800is that the pin1000is positioned within the primary direction1010such that at least two of the surfaces (opposite the side1001and opposite the side1002) are contacted by an initial flow of fluid. In other words, the sides1001and1002form approximately a 45° angle with respect to the direction of flow. The dimension a for the pin1000ranges from 10 microns to 1,000 microns. As mentioned before, the primary direction of flow is in the direction1010, as depicted by the arrow carrying that reference numeral. The flow direction can also go in a secondary direction, such as shown by the arrow1020inFIG. 10.

FIG. 11shows a cross-sectional view of a micropin thermal solution or pin1100, in accordance with yet another embodiment of this invention. As shown inFIG. 11, the cross-section shape of the pin1100is substantially circular or round. The dimension of the substantially circular or round pin includes that the pin has a radius, r, in the range of 50 microns to 500 microns. The pin1100is positioned within a flow of fluid having a primary direction1110and a secondary direction1120.

FIG. 12illustrates a cross-sectional view of a micropin thermal solution or pin1200, in accordance with another embodiment of the invention. The cross-sectional area of the pin is substantially elliptical. As shown inFIG. 12, the elliptical cross section1205has a major access1201and a minor access1202. The major access1201has a dimension2a, and the minor access1202has a dimension2b. The dimensions of2aand2bare unequal. The dimensions2aand2balso are in a range from 10 microns to 1,000 microns. The pin1200is situated within a primary flow direction1210. The elliptical cross section may be orientated either vertically or horizontally with respect to the primary flow direction1210. It should also be noted that, if necessary, flow can also occur in a secondary direction, as depicted by the arrow1220.

FIG. 13illustrates a cross-sectional view of a micropin or pin1300, in accordance with still another embodiment of the invention. The pin1300is essentially wedge shaped with rounded ends. A first end has a radius, r1,1301and the second end has a radius, r2,1302. In some embodiments, r1can be substantially the same as r2. In other embodiments, r1is different or unequal to r2. The pin1300is positioned within a flow1310. As shown inFIG. 13, the pin1300has the smaller radius end positioned toward the flow direction1310. The pin1300also has a length l. The radius r1and r2range between 10 microns and 100 microns. Although the primary flow direction is depicted by reference numeral1310, the flow is also capable of a secondary direction1320. It should be noted that even though the secondary flow direction820,920,1020,1120,1220,1320is shown perpendicular to a primary flow direction and directed downwardly, the secondary flow direction is not limited to the direction shown but can be any direction.

Also of note is that the various geometric shapes shown inFIGS. 8-13are not meant to be limiting and that other shapes may be used for cross-sectional shapes of pins or micropins in a micropin thermal solution. The shapes are also positionable within a primary flow direction in any number of ways.

The pin depth is not limited to any one particular depth, especially when the plurality of pins is not fabricated in the back of an integrated circuit die. The maximum depth is limited by the mechanical strength of the remaining silicon when the pin grids are formed within the back of the integrated circuit die. When the pin grid is formed of a separate material, the depth is not limited. The minimum depth is related to the required flow rate and allowable pressure drop through the pin grid array that will still provide sufficient cooling or remove an appropriate amount of heat from the integrated circuit.

Having described and illustrated the principles of the invention with reference to illustrated embodiments, it will be recognized that the illustrated embodiments can be modified in arrangement and detail without departing from such principles. And, though the foregoing discussion has focused on particular embodiments, other configurations are contemplated. In particular, even though expressions such as “in one embodiment,” “in another embodiment,” or the like are used herein, these phrases are meant to generally reference embodiment possibilities, and are not intended to limit the invention to particular embodiment configurations. As used herein, these terms may reference the same or different embodiments that are combinable into other embodiments.

Thus, it can be seen from the above descriptions, a novel apparatus including a micropin thermal solution has been described. The micropins allow for efficient 2-phase liquid cooling near a “hot-spot” where heat is generated on a chip when compared to channels. The pressure in a channel will increase when the liquid converts to a gas compared to the other channels of the microchannel device. Liquid preferentially flows in the channels with no pressurized gas. Since less liquid flows in the channel with gas, the cooling capability of this channel decreases. This is undesirable since this channel needs the most cooling. Pin grids avoid this since the water is not constrained within a channel and can move in two dimensions.