Patent Application
20090321925
Embodiments of the present invention generally relate to the field of integrated circuit package design and, more particularly, to an injection molded metal IC package stiffener and package-to-package interconnect frame.
As microelectronic components shrink in size, a trend has emerged to provide package substrates that may be characterized as thin core substrates (that is, substrates having a core with a thickness less than or equal to 400 microns and larger than zero), or no-core substrates (that is, substrates without cores).
Disadvantageously, with a thin or no-core substrate, however, decrease in yield at first level chip attach due to warpage causing nonwets may occur during the package manufacturing process, such as, for example, during flip chip bonding where substrate flatness and rigidity are required. To address the above issue, the prior art sometimes provides substrates that may have a thickness of at least several tens of microns or more. However, the above measure disadvantageously detracts from further package size minimization.
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:
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.
Microelectronic device 102 is intended to represent any type of integrated circuit die. In one embodiment, microelectronic device 102 is a multi-core microprocessor. Microelectronic device 102 includes an active surface which contains the electrical connections that couple with conductive traces 114 at substrate top surface 106.
Package substrate 104 represents any type of microelectronic device package substrate. In one embodiment, package substrate 104 represents a multi-layer organic substrate. In one embodiment, conductive traces 114 conductively couple microelectronic device 102 on substrate top surface 106 through build up layers to conductive contacts 117. Conductive contacts 117 couple with conductive traces 114 and allow integrated circuit package 100 to be electrically coupled, for example by a socket connection, to a circuit board. In one embodiment, conductive contacts 117 include solder bumps. In another embodiment, conductive contacts 117 include lands.
Injection molded metal stiffener 108 is attached to package substrate 104 to provide stiffening, which one skilled in the art would recognize may be essential for very thin packages. Injection molded metal stiffener 108 may include a central opening and at least partially surrounds microelectronic device 102. Injection molded metal stiffener 108 may border all or fewer than all sides of microelectronic device 102. The mold used to create injection molded metal stiffener 108 may include features such as stiffener overhang 110, which may be designed to extend along one or more side(s) of package substrate 104, and/or stiffener rib 112, which may be designed to extend vertically up from injection molded metal stiffener 108. Injection molded metal stiffener 108 may also include a plurality of through vias 113 that each couple a contact on a bottom surface of injection molded metal stiffener 108 with a respective contact on stiffener top surface 118. Through vias 113 may couple with conductive traces 115 and/or conductive traces 116 to interconnect contacts on stiffener top surface 118 with microelectronic device 102 and/or conductive contacts 117, respectively.
In one embodiment, injection molded metal stiffener 108 is composed substantially of magnesium. In other embodiments, injection molded metal stiffener 108 may be composed of magnesium-zinc, magnesium-aluminum, or other magnesium or aluminum or zinc alloys. In one embodiment, the metal used to mold injection molded metal stiffener 108 is chosen for thixotropic properties, such that when heated near its melting point and shear forces are applied, the metal may have viscous or plastic-like flow properties.
Injection molded metal stiffener 108 may be coupled with package substrate 104 before or after or contemporaneous to microelectronic device 102 is coupled with package substrate 104. Package substrate 104 may include copper pad 120 through which injection molded metal stiffener 108 is soldered to package substrate 104. In another embodiment, a polymer adhesive is used to bond injection molded metal stiffener 108 with package substrate 104. Injection molded metal stiffener 108 may have a stiffener height 122 of a little as about 12 mils.
Second microelectronic device package 202 represents any type of device package. In various embodiments, second microelectronic device package 202 may represent, for example, a chip scale package, a bump-less build up layer package, or a flip chip package, among others. Interconnects 204 conductively couple second microelectronic device package 202 with through vias 113. While shown as solder balls, interconnects 204 may take other forms, such as, for example, wire bonds.
Package substrate 304 may represent a bump-less build up layer substrate. In one embodiment, microelectronic device 302 and injection molded metal stiffener 306 are placed on a holding plate while encapsulation material is disposed between them forming a bond. Injection molded metal stiffener 306 may include a central opening and at least partially surrounds microelectronic device 302. Injection molded metal stiffener 306 may be adjacent to all or fewer than all sides of microelectronic device 302. Substrate top surface 312 may then be formed under the device and stiffener combination, followed by subsequent substrate layers.
Through via 308 may be formed by incorporating a void into the mold for injection molded metal stiffener 306 or by other mechanical methods. Integrated heat spreader 310 may also be incorporated into the mold for injection molded metal stiffener 306 for coupling with, and spreading heat from, microelectronic device 302. In one embodiment, stiffener height 314 is substantially equal to the height of microelectronic device 302.
Second microelectronic device package 402 represents any type of device package. In various embodiments, second microelectronic device package 402 may represent, for example, a chip scale package, a bump-less build up layer package, or a flip chip package, among others. Interconnects 404 conductively couple second microelectronic device package 402 with integrated circuit package 300. While shown as solder balls, interconnects 404 may take other forms, such as, for example, wire bonds.
Processor(s) 502 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) 502 are Intel® compatible processors. Processor(s) 502 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 504 may represent any type of chipset or control logic that interfaces system memory 506 with the other components of electronic appliance 500. In one embodiment, the connection between processor(s) 502 and memory controller 504 may be a point-to-point serial link. In another embodiment, memory controller 504 may be referred to as a north bridge.
System memory 506 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) 502. Typically, though the invention is not limited in this respect, system memory 506 will consist of dynamic random access memory (DRAM). In one embodiment, system memory 506 may consist of Rambus DRAM (RDRAM). In another embodiment, system memory 506 may consist of double data rate synchronous DRAM (DDRSDRAM).
Input/output (I/O) controller 508 may represent any type of chipset or control logic that interfaces I/O device(s) 512 with the other components of electronic appliance 500. In one embodiment, I/O controller 508 may be referred to as a south bridge. In another embodiment, I/O controller 508 may comply with the Peripheral Component Interconnect (PCI) Express™ Base Specification, Revision 1.0a, PCI Special Interest Group, released Apr. 15, 2003.
Network controller 510 may represent any type of device that allows electronic appliance 500 to communicate with other electronic appliances or devices. In one embodiment, network controller 510 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 510 may be an Ethernet network interface card.
Input/output (I/O) device(s) 512 may represent any type of device, peripheral or component that provides input to or processes output from electronic appliance 500.
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.
