Patent Application
20160079141
As microelectronic packaging technology advances for higher processor performance, advances in packaging structures may include improving temperature management when implementing thermal interface materials (TIMs). Many packaging applications require the use of TIMs, wherein the TIM may be used within a package structure itself, and in locations outside the package structure. Thermal performance is an important requirement of a TIM. Some package applications may possess more aggressive thermal requirements, such as packages comprising server central processing units (CPU's) for example, while other applications, such as packages comprising memory dies for example, may have less aggressive thermal requirements. Additionally, it is important for a TIM to provide good mechanical coupling between surfaces. Some applications may require a TIM to be a compliant link in order to reduce the risk of mechanical failure during operation, while other applications may require a more rigid TIM for optimal mechanical performance.
While the specification concludes with claims particularly pointing out and distinctly claiming certain embodiments, the advantages of these embodiments can be more readily ascertained from the following description of the invention when read in conjunction with the accompanying drawings in which:
a-1h represent structures according to various embodiments.
a-2d represent methods according to embodiments.
In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the methods and structures may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments. 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 embodiments. 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 embodiments. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the embodiments is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled. In the drawings, like numerals may refer to the same or similar functionality throughout the several views.
Methods and associated structures of forming and utilizing microelectronic structures, such as TIM structures associated with various package structures, are described. Those methods/structures may include forming a TIM comprising a thermally conductive serpentine foil material located between a first and a second interface material, in embodiments. The serpentine foil may be in a parallel position or a rotated position, in embodiments. The TIM structures of the various embodiments disclosed herein greatly improve both thermal and mechanical reliability of package structures incorporating the TIM structures included herein.
a-1h illustrate embodiments of methods of forming microelectronic structures, such as a TIM structure (
In an embodiment, a first interface material 102, which may comprise a thin coating of a soft, curable and/or reflow-able material, may be formed/placed on the substrate 100 (
In an embodiment, the first interface material 102 may serve to reduce the thermal contact resistance between a subsequently placed/formed serpentine foil component (to be described further herein) and the substrate 100 and/or a subsequently placed/formed integrated heat structure (IHS). Overall thermal performance may thus be improved in devices utilizing the TIM structures herein. but may comprise other materials depending upon the particular application.
A serpentine foil 104, may be formed/placed on the first interface material 102 (
Because of the serpentine foil 104 shape, a TIM comprising the serpentine foil 104 may exhibit high levels of elastic recovery; in some cases the elastic recovery may be more than an order of magnitude higher than non-serpentine TIM structures. This property reduces the risk of thermal degradation of the TIM structures herein by maintaining contact through temperature cycling.
The serpentine foil 104 may comprise a repeating serpentine pattern. In an embodiment, the repeating serpentine pattern of the serpentine foil 104 may comprise a repeating loop pattern 114, as depicted in
In an embodiment, a second interface material 106 may be formed/placed on the serpentine foil 104 (
In an embodiment, the apex portions 105 of the serpentine foil 104 may be disposed in a substantially parallel position/angle 107 with at least one of the first and second interface materials 102, 106. In an embodiment, the apex portions 105 of the serpentine foil 104 may be in contact with at least one of the first and second interface materials 102, 106. An IHS 108 (which may comprise a heat sink in some cases) may be placed/disposed on the second interface material 106. In an embodiment, the TIM structure 110 may comprise a portion of a microelectronic package structure 120. In an embodiment, the TIM structure 110 may comprise a parallel TIM structure 110, since the serpentine foil 104 of the TIM structure 110 is oriented in a substantially parallel position in relation to the first and second interface materials 102, 106.
f depicts a TIM structure 110′ comprising a rotated serpentine foil 104′. The rotated serpentine foil 104′ may be formed by applying a shear force to the serpentine foil before it is assembled within the interface material. The rotation has the effect of greatly increasing the compliance of the rotated TIM structure 110′ when under a compression state, which is desirable in certain applications. For example, the rotated TIM structure 110′ may comprise a much lower stiffness than the parallel TIM structure 110 of
In an embodiment, an apex portion 105 of the rotated serpentine foil 104′ is disposed in a rotated alignment with respect to at least one of the first and second interface materials 102, 106. In an embodiment, an angle 126 between at least one of the first and second interface materials 102, 106 and the tangent line 107 of the apex portion 105 of the serpentine foil 104′ may not be substantially perpendicular to at least one of the first and second interfaces 102, 106. In another embodiment, the angle 126 may comprise between about a 10 degree to about a 50 degree angle 126, in relation to the first and second interface materials 102, 106. In an embodiment, the rotated TIM structure 110′ may comprise a portion of a package structure 121, wherein an IHS 108 (which may comprise a heat sink in some cases) may be placed/disposed on the second interface material 106.
g depicts a package structure 124, wherein a first TIM structure 110 is disposed in a first location between a bottom portion of an IHS 114 and a top portion of a device 112, and a second TIM structure 111 is disposed in a second location between a top portion of the IHS 114 and a top portion of a heat sink 129. The device 112 may comprise one of a microelectronic memory die and a central processing unit die in some cases, but may comprise any type of suitable device 112 according to the particular application in other cases. The first TIM structure 110 may comprise one of a parallel TIM structure and a rotated TIM structure (as depicted in
In
In the package structures of
The package structures of the embodiments herein may also provide structural support for a device, such as a die. By way of example, in one embodiment, the package structures may comprise a multi-layer substrate—including alternating layers of a dielectric material and metal—built-up around a core layer (either a dielectric or metal core). In another embodiment, the package substrates may comprise a coreless multi-layer substrate. Other types of substrates and substrate materials may also find use with the disclosed embodiments (e.g., ceramics, sapphire, glass, etc.).
A die in the various Figures herein may comprise a silicon logic die or a memory die, for example, or any type of suitable microelectronic device/die, and may be disposed on a back side or on a front side of the package structures herein. In some embodiments the package structures may further comprise a plurality of dies, which may be stacked upon one another, depending upon the particular embodiment. In some cases the die(s) may be located/attached/embedded on either the front side, back side or on/in some combination of the front and back sides of the package structures. In an embodiment, the die(s) may be partially or fully embedded in the package structures of the embodiments.
a-2d depict processes/methods by which the serpentine foil may be manufactured/formed. In
d depicts a serpentine foil 204 that may undergo a rotation process 218. The serpentine foil 204 may be transferred to a structure 214 comprising a cavity of a specific depth 216 that may be slightly less than the height 209 of the serpentine foil 204. A top plate 215 may be passed over the serpentine foil 204 while applying downward and lateral forces 213, thus causing the serpentine foil 204 to achieve a desired rotation. In some cases, the processes depicted in
The various embodiments of TIM structures included herein promote and improve thermal and mechanical reliability for the package structures that utilize the TIM structures described herein. In some embodiments, the various TIM structures herein comprise thermal conductivity values in the range of up to about 80 Watts per meter degrees Kelvin. The TIM structures herein increase the capability for improved thermal performance and cost reduction. Additionally, the reduced stress levels of the TIM structures disclosed herein relieve mechanical reliability risks that may be present in the overall package structure utilizing the TIM's herein. The TIM's of the embodiments herein can provide greater flexibility in package design choice, with opportunities to improve both cost and performance.
Turning now to
System 300 may comprise any type of computing system, such as, for example, a hand-held or mobile computing device (e.g., a cell phone, a smart phone, a mobile internet device, a music player, a tablet computer, a laptop computer, a nettop computer, etc.). However, the disclosed embodiments are not limited to hand-held and other mobile computing devices and these embodiments may find application in other types of computing systems, such as desk-top computers and servers.
Mainboard 310 may comprise any suitable type of circuit board or other substrate capable of providing electrical communication between one or more of the various components disposed on the board. In one embodiment, for example, the mainboard 310 comprises a printed circuit board (PCB) comprising multiple metal layers separated from one another by a layer of dielectric material and interconnected by electrically conductive vias. Any one or more of the metal layers may be formed in a desired circuit pattern to route—perhaps in conjunction with other metal layers—electrical signals between the components coupled with the board 310. However, it should be understood that the disclosed embodiments are not limited to the above-described PCB and, further, that mainboard 310 may comprise any other suitable substrate.
In addition to the package structure 340, one or more additional components may be disposed on either one or both sides 312, 314 of the mainboard 310. By way of example, as shown in the figures, components 301a may be disposed on the first side 312 of the mainboard 310, and components 301b may be disposed on the mainboard's opposing side 314. Additional components that may be disposed on the mainboard 310 include other IC devices (e.g., processing devices, memory devices, signal processing devices, wireless communication devices, graphics controllers and/or drivers, audio processors and/or controllers, etc.), power delivery components (e.g., a voltage regulator and/or other power management devices, a power supply such as a battery, and/or passive devices such as a capacitor), and one or more user interface devices (e.g., an audio input device, an audio output device, a keypad or other data entry device such as a touch screen display, and/or a graphics display, etc.), as well as any combination of these and/or other devices.
In one embodiment, the computing system 300 includes a radiation shield. In a further embodiment, the computing system 300 includes a cooling solution. In yet another embodiment, the computing system 300 includes an antenna. In yet a further embodiment, the assembly 300 may be disposed within a housing or case. Where the mainboard 310 is disposed within a housing, some of the components of computer system 300—e.g., a user interface device, such as a display or keypad, and/or a power supply, such as a battery—may be electrically coupled with the mainboard 310 (and/or a component disposed on this board) but may be mechanically coupled with the housing.
In an embodiment, the electronic system 400 is a computer system that includes a system bus 420 to electrically couple the various components of the electronic system 400. The system bus 420 is a single bus or any combination of busses according to various embodiments. The electronic system 400 includes a voltage source 430 that provides power to the integrated circuit 410. In some embodiments, the voltage source 430 supplies current to the integrated circuit 410 through the system bus 420.
The integrated circuit 410 is electrically, communicatively coupled to the system bus 420 and includes any circuit, or combination of circuits according to an embodiment, including the package/device of the various embodiments included herein. In an embodiment, the integrated circuit 410 includes a processor 412 that can include any type of packaging structures according to the embodiments herein. As used herein, the processor 412 may mean any type of circuit such as, but not limited to, a microprocessor, a microcontroller, a graphics processor, a digital signal processor, or another processor. In an embodiment, the processor 412 includes any of the embodiments of the package structures disclosed herein. In an embodiment, SRAM embodiments are found in memory caches of the processor.
Other types of circuits that can be included in the integrated circuit 410 are a custom circuit or an application-specific integrated circuit (ASIC), such as a communications circuit 414 for use in wireless devices such as cellular telephones, smart phones, pagers, portable computers, two-way radios, and similar electronic systems. In an embodiment, the processor 412 includes on-die memory 416 such as static random-access memory (SRAM). In an embodiment, the processor 412 includes embedded on-die memory 416 such as embedded dynamic random-access memory (eDRAM).
In an embodiment, the integrated circuit 410 is complemented with a subsequent integrated circuit 411. In an embodiment, the dual integrated circuit 411 includes embedded on-die memory 417 such as eDRAM. The dual integrated circuit 411 includes an RFIC dual processor 413 and a dual communications circuit 415 and dual on-die memory 417 such as SRAM. The dual communications circuit 415 may be configured for RF processing.
At least one passive device 480 is coupled to the subsequent integrated circuit 411. In an embodiment, the electronic system 400 also includes an external memory 440 that in turn may include one or more memory elements suitable to the particular application, such as a main memory 442 in the form of RAM, one or more hard drives 444, and/or one or more drives that handle removable media 446, such as diskettes, compact disks (CDs), digital variable disks (DVDs), flash memory drives, and other removable media known in the art. The external memory 440 may also be embedded memory 448. In an embodiment, the electronic system 400 also includes a display device 450, and an audio output 460. In an embodiment, the electronic system 400 includes an input device such as a controller 470 that may be a keyboard, mouse, touch pad, keypad, trackball, game controller, microphone, voice-recognition device, or any other input device that inputs information into the electronic system 400. In an embodiment, an input device 470 includes a camera. In an embodiment, an input device 470 includes a digital sound recorder. In an embodiment, an input device 470 includes a camera and a digital sound recorder.
Although the foregoing description has specified certain steps and materials that may be used in the methods of the embodiments, those skilled in the art will appreciate that many modifications and substitutions may be made. Accordingly, it is intended that all such modifications, alterations, substitutions and additions be considered to fall within the spirit and scope of the embodiments as defined by the appended claims. In addition, the Figures provided herein illustrate only portions of exemplary microelectronic devices and associated package structures that pertain to the practice of the embodiments. Thus the embodiments are not limited to the structures described herein.
The present application is a Divisional of U.S. patent application Ser. No. 13/724,511filed on Dec. 21, 2012, entitled “Methods of Forming Serpentine Thermal Interface Material and Structure Formed Thereby”.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13724511 | Dec 2012 | US |
| Child | 14952651 | US |
