Abstract:
In some embodiments, a thermal spacer for stacked die package thermal management is presented. In this regard, an apparatus is introduced having a top integrated circuit die, a bottom integrated circuit die, and a thermal spacer between the top and bottom integrated circuit dice, the thermal spacer comprising a heat conducting material and the thermal spacer overhanging and extending parallel with one outside edge of the bottom integrated circuit die. Other embodiments are also disclosed and claimed.

Description:
CLAIM OF PRIORITY 
     This application is a continuation of and claims priority to U.S. patent application Ser. No. 11/644,297 filed on Dec. 22, 2006 now U.S. Pat. No. 7,723,841 entitled “Thermal Spacer for Stacked Die Package Thermal Management,” now allowed. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the present invention generally relate to the field of integrated circuit packages, and, more particularly to a thermal spacer for stacked die package thermal management. 
     BACKGROUND OF THE INVENTION 
     The demand for enhanced performance and functionality of integrated circuit components continues to increase design and fabrication complexity. An integrated circuit package can have increased flexibility and functionality within the same footprint by stacking multiple dice on top of each other. However, if the dice to be stacked are high frequency active dice, there could be thermal management issues. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements, and in which: 
         FIG. 1  is a graphical illustration of a three-dimensional view of a thermal spacer for stacked die package thermal management, in accordance with one example embodiment of the invention; 
         FIG. 2  is a graphical illustration of a cross-sectional view of a stacked die package with a thermal spacer for stacked die package thermal management, in accordance with one example embodiment of the invention; and 
         FIG. 3  is a block diagram of an example electronic appliance suitable for implementing a thermal spacer for stacked die package thermal management, in accordance with one example embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that embodiments of the invention can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the invention. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. 
       FIG. 1  is a graphical illustration of a three-dimensional view of a thermal spacer for stacked die package thermal management, in accordance with one example embodiment of the invention. In accordance with the illustrated example embodiment, thermal spacer  100  includes one or more of contact surface  102 , edge overhangs  104 , pin  106 , and wirebond edge  108 . 
     Thermal spacer  100  may be made of any heat conductive material. In one embodiment, thermal spacer  100  is made primarily of ceramic. In another embodiment, thermal spacer  100  is made primarily of metal. 
     Contact surface  102  is designed to contact the top surface of an integrated circuit die in a stacked die thermal package, as depicted in  FIG. 2 . Heat from the integrated circuit die would be conducted through contact surface  102  to throughout thermal spacer  100 . 
     Edge overhangs  104  are designed to hang over and extend along an outside edge of the associated integrated circuit die. In one embodiment, the height of edge overhangs  104  is designed to contact a package substrate. One skilled in the art would appreciate that edge overhangs  104  would enable heat to be further distributed. While depicted with two edge overhangs  104 , thermal spacer  100  may also be implemented with overhangs on just one or on three sides of contact surface  102 . 
     Pin  106 , included in some embodiments of thermal spacer  100 , is designed to mate with a hole in a package substrate, as depicted in  FIG. 2 , to further distribute heat. 
     Wirebond edge  108  is designed to allow contacts on an associated integrated circuit die to be exposed to allow for wirebonding, as depicted in  FIG. 2 . Wirebond edge  108  may also be implemented on two or three sides of contact surface  102 . 
       FIG. 2  is a graphical illustration of a cross-sectional view of a stacked die package with a thermal spacer for stacked die package thermal management, in accordance with one example embodiment of the invention. As shown, package  200  includes one or more of substrate  202 , bottom die  204 , adhesive  206 , top die  208 , thermal spacer  210 , top die wire  212 , bottom die wire  214 , overhang edge  216 , pin  218 , mold  220 , and solder ball  222 . 
     Substrate  202  represents a substrate that may comprise multiple conductive layers laminated together. Substrate  202  may be laminated with dielectric material as part of a substrate build-up and may have insulated traces and vias routed through it. 
     Bottom die  204  represents an integrated circuit die. In one embodiment, bottom die  204  represents a memory device. In another embodiment, bottom die  204  represents a logic device. Bottom die  204  is mechanically attached to substrate  202  by adhesive  206 , which represents a thin-film attachment material. Top die  208  is mechanically attached to thermal spacer  210  by adhesive. In one embodiment, top die  208  is a radio frequency (RF) media access control (MAC) integrated circuit (IC) die and bottom die  204  is a RF radio IC die. 
     Thermal spacer  210  is comprised primarily of a heat conducting material, such as silicon, diamond, ceramic or metal, to distribute heat from the top of bottom die  204  and the bottom of top die  208 . 
     Top die wire  212  and bottom die wire  214  represents wirebonding that electrically couples top die  208  and bottom die  204 , respectively, to contacts on top of surface  202 . 
     Overhang edge  216  of thermal spacer  210  overhangs and extends parallel with one outside edge of bottom die  204 . As shown, overhang edge  216  contacts substrate  202  enabling further distribution of heat. While shown overhanging one side of bottom die  204 , overhang edge  216  may be implemented on any number of sides so long as accommodations are made for wirebonding. 
     Pin  218  may be coupled to overhang edge  216  to mate with a hole in substrate  202 , enabling further distribution of heat. 
     Mold  220  is used to protect dice  204  and  208  as well as wires  212  and  214 . In one embodiment, mold  220  is an epoxy resin compound. 
     Solder ball  222  may be added to package  200  to allow package  200  to be coupled, for example to a substrate or printed circuit board. Other electrical interfaces besides solder balls may also be utilized. 
       FIG. 3  is a block diagram of an example electronic appliance suitable for implementing a thermal spacer for stacked die package thermal management, in accordance with one example embodiment of the invention. Electronic appliance  300  is intended to represent any of a wide variety of traditional and non-traditional electronic appliances, laptops, desktops, cell phones, wireless communication subscriber units, wireless communication telephony infrastructure elements, personal digital assistants, set-top boxes, or any electric appliance that would benefit from the teachings of the present invention. In accordance with the illustrated example embodiment, electronic appliance  300  may include one or more of processor(s)  302 , memory controller  304 , system memory  306 , input/output controller  308 , network controller  310 , and input/output device(s)  312  coupled as shown in  FIG. 3 . Network controller  310 , or other integrated circuit components of electronic appliance  300 , may be housed in a package including a slotted substrate described previously as an embodiment of the present invention. 
     Processor(s)  302  may represent any of a wide variety of control logic including, but not limited to one or more of a microprocessor, a programmable logic device (PLD), programmable logic array (PLA), application specific integrated circuit (ASIC), a microcontroller, and the like, although the present invention is not limited in this respect. In one embodiment, processors(s)  302  are Intel® compatible processors. Processor(s)  302  may have an instruction set containing a plurality of machine level instructions that may be invoked, for example by an application or operating system. 
     Memory controller  304  may represent any type of chipset or control logic that interfaces system memory  306  with the other components of electronic appliance  300 . In one embodiment, the connection between processor(s)  302  and memory controller  304  may be referred to as a front-side bus. In another embodiment, memory controller  304  may be referred to as a north bridge. 
     System memory  306  may represent any type of memory device(s) used to store data and instructions that may have been or will be used by processor(s)  302 . Typically, though the invention is not limited in this respect, system memory  306  will consist of dynamic random access memory (DRAM). In one embodiment, system memory  306  may consist of Rambus DRAM (RDRAM). In another embodiment, system memory  306  may consist of double data rate synchronous DRAM (DDRSDRAM). 
     Input/output (I/O) controller  308  may represent any type of chipset or control logic that interfaces I/O device(s)  312  with the other components of electronic appliance  300 . In one embodiment, I/O controller  308  may be referred to as a south bridge. In another embodiment, I/O controller  308  may comply with the Peripheral Component Interconnect (PCI) Express™ Base Specification, Revision 1.0a, PCI Special Interest Group, released Apr. 15, 2003. 
     Network controller  310  may represent any type of device that allows electronic appliance  300  to communicate with other electronic appliances or devices. In one embodiment, network controller  310  may comply with a The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 802.11b standard (approved Sep. 16, 1999, supplement to ANSI/IEEE Std 802.11, 1999 Edition). In another embodiment, network controller  310  may be an Ethernet network interface card. 
     Input/output (I/O) device(s)  312  may represent any type of device, peripheral or component that provides input to or processes output from electronic appliance  300 . 
     In the description above, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form. 
     Many of the methods are described in their most basic form but operations can be added to or deleted from any of the methods and information can be added or subtracted from any of the described messages without departing from the basic scope of the present invention. Any number of variations of the inventive concept is anticipated within the scope and spirit of the present invention. In this regard, the particular illustrated example embodiments are not provided to limit the invention but merely to illustrate it. Thus, the scope of the present invention is not to be determined by the specific examples provided above but only by the plain language of the following claims.