Embodiments of the present description generally relate to the removal of heat from microelectronic devices, and, more particularly, to thermal management solutions wherein a jumping drops vapor chamber is utilized between a microelectronic device and an integrated heat spreader.
Higher performance, lower cost, increased miniaturization of integrated circuit components, and greater packaging density of integrated circuits are ongoing goals of the microelectronic industry. As these goals are achieved, microelectronic devices become smaller. Accordingly, the density of power consumption of the integrated circuit components in the microelectronic devices has increased, which, in turn, increases the average junction temperature of the microelectronic device. If the temperature of the microelectronic device becomes too high, the integrated circuits of the microelectronic device may be damaged or destroyed. This issue becomes even more critical when multiple microelectronic devices are incorporated in close proximity to one another in a multiple microelectronic device package, also known as a multi-chip package. Thus, thermal transfer solutions, such as integrated heat spreaders, must be utilized to remove heat from the microelectronic devices. However, the difficulty and cost of fabricating current designs for integrated heat spreaders for multi-chip packages has become an issue for the microelectronic industry.
The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. It is understood that the accompanying drawings depict only several embodiments in accordance with the present disclosure and are, therefore, not to be considered limiting of its scope. The disclosure will be described with additional specificity and detail through use of the accompanying drawings, such that the advantages of the present disclosure can be more readily ascertained, in which:
In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the claimed subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the subject matter. It is to be understood that the various embodiments, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein, in connection with one embodiment, may be implemented within other embodiments without departing from the spirit and scope of the claimed subject matter. References within this specification to “one embodiment” or “an embodiment” mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation encompassed within the present invention. Therefore, the use of the phrase “one embodiment” or “in an embodiment” does not necessarily refer to the same embodiment. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the claimed subject matter. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the subject matter is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the appended claims are entitled. In the drawings, like numerals refer to the same or similar elements or functionality throughout the several views, and elements depicted therein are not necessarily to scale with one another, rather individual elements may be enlarged or reduced in order to more easily comprehend the elements in the context of the present description.
The terms “over”, “to”, “between” and “on” as used herein may refer to a relative position of one layer with respect to other layers. One layer “over” or “on” another layer or bonded “to” another layer may be directly in contact with the other layer or may have one or more intervening layers. One layer “between” layers may be directly in contact with the layers or may have one or more intervening layers.
The microelectronic substrate 120 may be primarily composed of any appropriate material, including, but not limited to, bismaleimine triazine resin, fire retardant grade 4 material, polyimide materials, glass reinforced epoxy matrix material, and the like, as well as laminates or multiple layers thereof. The microelectronic substrate conductive routes (not shown) may be composed of any conductive material, including but not limited to metals, such as copper and aluminum, and alloys thereof. As will be understood to those skilled in the art, microelectronic interposer conductive routes (not shown) and the microelectronic substrate conductive routes (not shown) may be formed as a plurality of conductive traces (not shown) formed on layers of dielectric material (constituting the layers of the microelectronic substrate material), which are connected by conductive vias (not shown).
The device-to-substrate interconnects 126 can be made of any appropriate material, including, but not limited to, solders materials. The solder materials may be any appropriate material, including but not limited to, lead/tin alloys, such as 63% tin/37% lead solder, and high tin content alloys (e.g. 90% or more tin), such as tin/bismuth, eutectic tin/silver, ternary tin/silver/copper, eutectic tin/copper, and similar alloys. When the microelectronic devices 1101 an 1102 are attached to the microelectronic substrate 120 with device-to-substrate interconnects 126 made of solder, the solder is reflowed, either by heat, pressure, and/or sonic energy to secure the solder between the microelectronic device bond pads 114 and the microelectronic substrate bond pads 124.
As further illustrated in
The integrated heat spreader 140 may have a first surface 142 and an opposing second surface 144, wherein the integrated heat spreader second surface 144 includes at least two levels (illustrated as elements 1441 and 1442). As illustrated, the differing integrated heat spreader second surface levels 1441, and 1442 may compensate for differing heights H1 and H2 of the microelectronic devices 1101 and 1102 (i.e. the distance between the microelectronic substrate first surface 122 and a back surface 116 of each microelectronic devices 1101 and 1102), respectively, in order to make thermal contact therebetween. A thermal interface material 152, such as a thermally conductive grease or polymer, may be disposed between each integrated heat spreader second surface levels 1441 and 1442 and its respective back surface 116 of each microelectronic device 1101 and 1102 to facilitate heat transfer therebetween and to compensate for tolerances.
The integrated heat spreader 140 may include at least one footing 146 extending between the integrated heat spreader second surface 144 and the microelectronic substrate 120, wherein the integrated heat spreader footing 146 may be attached to the microelectronic substrate first surface 122 with an adhesive material 154.
As still further illustrated in
As will be understood to those skilled in the art, the fabrication of the integrated heat spreader 140 shown in
Embodiments of the present description relate to thermal solutions for microelectronic systems comprising a jumping drops vapor chamber disposed between an integrated heat spreader and a back surface of the microelectronic device in lieu of a thermal interface material.
As illustrated in
As illustrated in
In operation, as shown in
The jumping drops vapor chamber 200 differs from traditional vapor chambers in that traditional vapor chambers rely on capillary action for liquid return, requiring relatively long wicks to allow for the large working fluid flow rates that are necessary for cooling. However, relatively long wicks have a high thermal resistance, which reduces the overall thermal conductivity of the traditional vapor chamber. In jumping drops vapor chambers 200, the capillary limit of traditional vapor chambers is surpassed because the return is achieved by the jumping action previously described. The projections or wicks 224 of the hydrophilic evaporation surface 204 are now only used for capturing the returning working fluid drops 216, and, thus, can be made much shorter and finer than wicks in a traditional vapor chambers. This may lead to much higher thermal conductivities in the jumping drops vapor chamber 200 compared to traditional vapor chambers. Moreover, the finer projections or wicks 224 may allow higher heat flux before boiling incipiency and may expand the range of allowable heat fluxes before dry-out occurs, as will be understood to those skilled in the art. Furthermore, as will also be understood to those skilled in the art, the microelectronic device 1101 and 1102 may have specific areas that are hotter than other areas during operation, known as hot spot areas. The jumping drops vapor chamber 200 may act to dynamically mitigate such hot spots areas due to the fact that the evaporation rate of the working fluid 214 will be higher in hot spot areas than other areas, leading to fast temperature uniformity without requiring any special designs for the hot spot areas.
As illustrated in
In one embodiment of the present description, the jumping drops vapor chamber sidewalls 212 may comprise a seal, such as an O-ring. As will be understood to those skilled in the art, various commercial O-rings or other such materials are available that may be able to withstand temperature and humidity of the proposed environment, including but not limited to perfluoroelastomers (such as DuPont Kalrez®, available from E.I. du Pont de Nemours & Company, Wilmington, Del.) and Parker FF-400® O-rings (available from Parker Hannifin Corporation, Lexington, Ky.). In an embodiment, the jumping drops vapor chamber sidewalls 212 may be compliant to absorb manufacturing tolerances, as will be understood to those skilled in the art. Furthermore, as shown in
As further illustrated in
The communication chip enables wireless communications for the transfer of data to and from the computing device. The term “wireless” and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that may communicate data through the use of modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated devices do not contain any wires, although in some embodiments they might not. The communication chip may implement any of a number of wireless standards or protocols, including but not limited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as any other wireless protocols that are designated as 3G, 4G, 5G, and beyond. The computing device may include a plurality of communication chips. For instance, a first communication chip may be dedicated to shorter range wireless communications such as Wi-Fi and Bluetooth and a second communication chip may be dedicated to longer range wireless communications such as GPS, EDGE, GPRS, CDMA, WiMAX, LTE, Ev-DO, and others.
The term “processor” may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory.
At least one of the microelectronic components may include a thermal solution comprising a jumping drops vapor chamber disposed between an integrated heat spreader and a back surface of the microelectronic device within the microelectronic component.
In various implementations, the computing device may be a laptop, a netbook, a notebook, an ultrabook, a smartphone, a tablet, a personal digital assistant (PDA), an ultra mobile PC, a mobile phone, a desktop computer, a server, a printer, a scanner, a monitor, a set-top box, an entertainment control unit, a digital camera, a portable music player, or a digital video recorder. In further implementations, the computing device may be any other electronic device that processes data.
It is understood that the subject matter of the present description is not necessarily limited to specific applications illustrated in
The following examples pertain to further embodiments, wherein Example 1 is a microelectronic system, comprising at least one microelectronic device having an active surface and an opposing back surface, wherein the at least one microelectronic device active surface is attached to a microelectronic substrate; an integrated heat spreader, having a first surface and an opposing second surface, attached to the microelectronic substrate; and a jumping drops vapor chamber disposed between the at least one microelectronic device back surface and the integrated heat spreader second surface, wherein the jumping drops vapor chamber comprises a vapor space defined by a hydrophilic evaporation surface formed on the at least one microelectronic device back surface, an opposing hydrophobic condensation surface formed on the integrated heat spreader second surface, and at least one sidewall extending between the hydrophilic evaporation surface and the hydrophobic condensation surface; and a working fluid disposed within the vapor space.
In Example 2, the subject matter of Example 1 can optionally include the hydrophilic evaporation surface comprising a plurality of wicks formed in the at least one microelectronic device back surface.
In Example 3, the subject matter of either Example 1 or 2 can optionally include the hydrophobic condensation surface comprising a hydrophobic material layer formed on the integrated heat spreader second surface.
In Example 4, the subject matter of Example 3 can optionally include the hydrophobic material layer comprises a self-assembled monolayer material selected from the group comprising thiols and silanes.
In Example 5, the subject matter of Example 1 can optionally include the at least one sidewall comprising at least one compliant sidewall.
In Example 6, the subject matter of Example 5 can optionally include the at least one compliant sidewall comprising an O-ring.
In Example 7, the subject matter of any of Examples 1 to 6 can optionally include the working fluid comprising deionized water.
In Example 8, the subject matter of any of Examples 1 to 6 can optionally include the working fluid comprising a dielectric liquid.
In Example 9, the subject matter of any of Examples 1 to 8 can optionally include a charging port extending through the integrated heat spreader to the vapor chamber.
In Example 10, the subject matter of any of Examples 1 to 9 can optionally include a groove formed in at least one of the microelectronic device back surface and the integrated heat spreader second surface; and wherein a portion of the jumping drops vapor chamber sidewall resides within the groove.
In Example 11, the subject matter of any of Examples 1 to 10 can optionally include a second microelectronic device having an active surface and an opposing back surface, wherein the second microelectronic device active surface is attached to the microelectronic substrate; and a second jumping drops vapor chamber disposed between the second microelectronic device back surface and the integrated heat spreader second surface, wherein the second jumping drops vapor chamber comprises a vapor space defined by a hydrophilic evaporation surface formed on the second microelectronic device back surface, an opposing hydrophobic condensation surface formed on the integrated heat spreader second surface, and at least one sidewall extending between the hydrophilic evaporation surface and the hydrophobic condensation surface; and a working fluid disposed within the vapor space.
In Example 12, the subject matter of Example 11 can optionally include a height of the at least one microelectronic device being less than a height of the second microelectronic device; and wherein the jumping drops vapor chamber sidewall is longer than the second jumping drops vapor chamber sidewall.
The following examples pertain to further embodiments, wherein Example 13 is a method for forming a microelectronic system, comprising forming a hydrophilic evaporation surface on a back surface of a microelectronic device; attaching an active surface of the microelectronic device to a microelectronic substrate; forming a hydrophobic condensation surface on a second surface of an integrated heat spreader; attaching the integrated heat spreader to the microelectronic substrate; disposing at least one sidewall extending between the hydrophilic evaporation surface and the hydrophobic condensation surface to form a vapor space; and disposing a working fluid in the vapor space.
In Example 14, the subject matter of Example 13 can optionally include disposing the working fluid within the vapor space comprises forming a charging port extending through the integrated heat spreader to the vapor space, injecting the working fluid through the charging port, and sealing the charging port.
In Example 15, the subject matter of Example 14 can optionally include creating a vacuum within the vapor space through the charging port prior to sealing the charging port.
In Example 16, the subject matter of any of Examples 13 to 15 can optionally include forming the hydrophilic evaporation surface comprising forming a plurality of wicks in the microelectronic device back surface.
In Example 17, the subject matter of any of Examples 13 to 16 can optionally include forming the hydrophobic condensation surface comprising forming a hydrophobic material layer form on the integrated heat spreader second surface.
In Example 18, the subject matter of Example 17 can optionally include forming the hydrophobic condensation surface comprising forming a hydrophobic material layer form on the integrated heat spreader second surface.
In Example 19, the subject matter of any of Examples 13 to 18 can optionally include disposing at least one sidewall extending between the hydrophilic evaporation surface and the hydrophobic condensation surface comprising disposing at least one compliant sidewall extending between the hydrophilic evaporation surface and the hydrophobic condensation surface.
In Example 20, the subject matter of any of Examples 13 to 19 can optionally include disposing the working fluid within the vapor space comprising disposing deionized water within the vapor space.
In Example 21, the subject matter of any of Examples 13 to 19 can optionally include disposing the working fluid within the vapor space comprising disposing a dielectric liquid within the vapor space.
The following examples pertain to further embodiments, wherein Example 22 is an electronic system, comprising a housing; a microelectronic substrate disposed within the housing; at least one microelectronic device having an active surface electrically connected to the microelectronic substrate; an integrated heat spreader, having a first surface and an opposing second surface, attached to the microelectronic substrate; and a jumping drops vapor chamber disposed between the at least one microelectronic device back surface and the integrated heat spreader second surface, wherein the jumping drops vapor chamber comprises: a vapor space defined by a hydrophilic evaporation surface formed on the at least one microelectronic device back surface, an opposing hydrophobic condensation surface formed on the integrated heat spreader second surface, and at least one sidewall extending between the hydrophilic evaporation surface and the hydrophobic condensation surface; and a working fluid disposed within the vapor space.
In Example 23, the subject matter of Example 22 can optionally include the hydrophilic evaporation surface comprising a plurality of wicks formed in the at least one microelectronic device back surface.
In Example 24, the subject matter of either Example 22 or 23 can optionally include the hydrophobic condensation surface comprising a self-assembled monolayer material selected from the group comprising thiols and silanes formed on the integrated heat spreader second surface.
In Example 25, the subject matter of any of Examples 22 to 24 can optionally include the at least one sidewall comprising at least one compliant sidewall.
Having thus described in detail embodiments of the present invention, it is understood that the invention defined by the appended claims is not to be limited by particular details set forth in the above description, as many apparent variations thereof are possible without departing from the spirit or scope thereof.