Abstract:
The assembly includes a mother board having a processor carrier having a processor attached thereto. A heat sink is thermally coupled to the processor carrier and is located on top of the carrier. A voltage regulating module board is electrically coupled to the processor carrier and is configured to be positioned adjacent to the heat sink and at substantially a right angle to the mother board.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 60/361,554, filed Mar. 4, 2002, by David H. Hartke and entitled “RIGHT ANGLE POWER CONNECTOR ARCHITECTURE” and U.S. Provisional Patent Applications No. 60/377,557, filed May 3, 2002, by DiBene, et. al. and entitled “EVRM STACK-UP, POWER DELIVERY SOLUTION”, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     CROSS-REFERENCE TO RELATED PATENTS 
     The following patents are incorporated by reference herein as related art U.S. Pat. No. 6,452,113, issued Sep. 17, 2002, by DiBene II, et al. and entitled “APPARATUS FOR PROVIDING POWER TO A MICROPROCESSOR WITH INTEGRATED THERMAL AND EMI MANAGEMENT”, U.S. Pat. No. 6,392,899, issued May 21, 2002, by Harrison, et al. and entitled “PROCESSOR POWER DELIVERY SYSTEM”, and U.S. Pat. No. 5,980,267, issued Nov. 9, 1999 by Ayers, et al. and entitled “CONNECTOR SCHEME FOR A POWER POD DELIVERY SYSTEM”. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a power distribution architecture and to such architecture where the power converter, or voltage regulation module (VRM), is mounted adjacent to a heatsink which cools an electronic device (such as a microprocessor) and where the VRM is interconnected electrically to the device package itself either directly or indirectly. 
     2. Description of the Related Art 
     High performance electronics today are demanding higher performance and lower cost power delivery than in previous years. As an example, high performance microprocessors are forcing power converters to supply voltages at 1V and below and deliver power over 100W. This translates to delivered currents in excess of 100 amps. Moreover, the small space allocated on mother boards and other printed circuit boards, along with the thermal considerations at the system level, require the voltage regulators to be highly efficient, have low noise, have low interconnect paths, and maintain very small form factors. This trend is creating new problems and challenges in power conversion technology and in packaging architectures for the VRM and microprocessors. 
     Today, there are numerous methods by which power is delivered to a high performance electronic device, such as a microprocessor. Typically, the power has been brought through the main board or mother board of the system, through the device socket and then into the microprocessor itself. Though this has been effective for many generations of microprocessors and high performance electronic devices it has its drawbacks. The voltage regulator components typically take up much real-estate on the mother board. Due to routing constraints the power is typically bused through only one side of the device and through a limited number of power/ground plane pairs. This results in not only a high DC resistance path but also a relatively high inductive path which increases AC and DC losses and can disrupt power delivery to the device itself. 
     Other approaches have removed this burden of busing power through the mother board by bringing power to one side of the substrate through an edge-card type connection or powerpod interconnect. This architecture bypasses the mother board and supplies power directly into the side of the substrate or interposer of the device. However, this approach is relatively expensive due to the complexity of the substrate design and the power module mechanical construction. 
     Another approach has been to bring power directly to the surface of the microprocessor through a z-axis power delivery approach. In this architecture, power is integrated with the thermal solution and is directly attached to the device package through a disconnectable interconnect. However, the VRM is oriented horizontal and is located above and over the device package. The power interconnection is made to the device package substrate surface on one or more sides. Thus, this architecture is somewhat integrated with the thermal solution of the device package. Though this may be desirable in many cases, in some designs where one wishes to disconnect the VRM without disrupting the thermal solution to the device package, an alternative approach is needed. 
     SUMMARY OF THE INVENTION 
     To address the requirements described above, and other needs, the present invention relates to a methods and an assemblies which provide a VRM board for a processor carrier. 
     In one aspect of the invention a VRM board is mounted at substantially a right angle to a processor carrier. 
     One aspect of the invention relates to an assembly including a mother board. A processor carrier is mounted to the mother board and a processor is mounted on the processor carrier. A heat sink is thermally coupled to the processor and is located adjacent to the top surface of the processor. A circuit board with a power conditioning circuit is mounted at substantially a right angle to the mother board and adjacent to the heat sink. An interconnect assembly provides an electrical path between electrical contacts of the processor carrier and the circuit board. 
     In one aspect of the invention an interconnect assembly provides a releasable connection for the processor carrier and/or the VRM board. 
     In another aspect of the invention a method includes mounting a processor carrier having a processor on a mother board. A heat sink is thermally coupled to the processor and is located over the processor. A VRM board is electrically coupled to the processor carrier and mounted so that the plane of VRM board is substantially orthogonal to the plane of the mother board. 
     The foregoing and aspects and other advantages of the invention will be apparent to those who are skilled in the art upon reviewing the detailed description in conjunction with the included drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings in which like reference numbers represent corresponding parts throughout: 
         FIG. 1A  is a side view of the right-angle VRM architecture for an unmodified interposer where an edge connector is connected to the end of the package on one side; 
         FIG. 1B  is a top view of the embodiment shown in  FIG. 1A  with a section taken out to show the connection methods; 
         FIG. 2  is a side view of a right-angle VRM architecture with the edge connector connected to one side of a modified interposer; 
         FIG. 3  is a side view of a right-angle VRM architecture which uses a connection method to both sides of the package, as in an edge connector, but with a bracket where the bracket is mechanically mounted to the interposer and is also electrically active (e.g. at ground); 
         FIG. 4  is an enlarged view of Section A of  FIG. 3 ; 
         FIG. 5  is a side view of a right-angle VRM architecture which uses a connection method for the right-angle VRM architecture where the electrical connection is made to one side of the substrate and VRM; 
         FIG. 6  shows an example power/ground pattern on the top side of the substrate for making electrical connection from the right-angle VRM to the substrate. 
         FIG. 7  is an enlarged view of Section B of  FIG. 5 ; 
         FIG. 8  is a side view of a right-angle architecture for interconnecting the substrate to the VRM with the use of an integrated connection system as part of the socket for the electronic device; 
         FIG. 9  is an enlarged view of Section C of  FIG. 8 ; 
         FIG. 10  is a side view of a right-angle architecture which makes the connection to the top surface of the substrate with a connector mounted to the VRM; and 
         FIG. 11  is an enlarged view of Section D of FIG.  10 . 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings which form a part hereof, and which is shown, by way of illustration, several embodiments of the present invention. It is understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention. 
     Referring to  FIG. 1A , an assembly  100  is shown in a side ‘end’ view—that is, shown from the perspective of one end of the assembly. Assembly  100  comprises a heat dissipating device  102 , such as a heat sink, and a VRM subassembly  104 . VRM subassembly  104  can include one or more power components on either or both sides of the VRM board  103 , such as component  105  shown on the front side of the VRM board or PCB  103  and component  107  shown on the back side of the VRM board  103 . Such components are used as part of a power conditioning circuit, such as a DC-to-DC converter, located on the VRM board  103 . The VRM assembly  104  is shown mounted to heatsink  102  via a fastening mechanism such as fastener  106 . The VRM assembly can be mounted to the heat dissipating device  102  using a removable fastener  106  or it can be permanently attached such as by soldering or gluing. Assembly  100  further includes an interconnect assembly including a flex circuit  108  which connects to an edge card connector  110 . The edge connector connects to an edge of the interposer board  114 . The flex circuit  108  connects to the edge connector  110  at a connection  111 . Interposer board  114  connects to a socket  112  with a socket actuation section  118 . The socket  112  connects to a main board  116  (which may be a mother board or other printed circuit board with electronic components) through interconnect  120  which is typically a ball grid array or maybe another interconnection methodology, such as a pin grid array or LAN grid array (LGA). Additionally, socket  112  may also be an LGA or some other socket type in which case actuation section  118  may or may not be required. 
       FIG. 1B  shows a partial cut-away top view of the assembly shown in FIG.  1 A. Note that fasteners  106 A and  106 B are shown on each end of the VRM subassembly  104  to ensure adequate attachment to heatsink  102 . Additionally, as can be seen in this view, flex circuit  108  egresses to the right side of VRM PCB  103  and connects to edge-card connector  110  which in turn connects to interposer  114 . This orientation is conductive to design where it is easier to connect the interposer on the end of the substrate and require less modification to the imposer. Typically, another substrate such as substrate  152  connects to interposer  114 . An electronic device, such as a microprocessor,  156 , is typically mounted to substrate  152  with lid  154  which protects the device from damage and helps in spreading heat for thermal management. Socket  112  typically has an actuation mechanism  118  with a feature such as a locking mechanism  150  for locking down the interposer to the socket and securing the electrical connections to the main board  116 . 
     The interposer  114 , and substrate  152  can collectively be referred to as a processor carrier. The term processor carrier also encompasses other arrangements used to couple a processor to a main board or mother board. For example, processor carriers include an organic land grid array (OLGA) with an interposer. Additionally, multiple processors and other devices can be packaged on the same interposer. Each of the assemblies described herein can be implemented with these various processor carriers. 
     One method to construct the assembly  100  is as follows. A processor  156  and its associated interposer board  114  can be inserted into the socket  112 . The heatsink  102  is then thermally coupled to the processor  156 . The heatsink  102  is also mechanically coupled to the interposer  114  and/or the main board  116 . The mechanical connection can be made with fastener, clamps or other suitable arrangements. The edge connector  110  is then connected to the appropriate end of the interposer  114 . The VRM subassembly is then attached to the heat dissipating device  102 , for example, a heatsink or vapor chamber. 
     The advantages of orienting the VRM board in a right-angle fashion (with regard to the mother board) and adjacent to the heatsink are that the voltage regulator (VR) components, its interconnects, and thermal management are lifted off of the main board. This results in less real-estate being taken up by the VRM which is an advantage over typical VRM designs as well as voltage regulators which have components mounted onto the main board itself. 
     Of course, in all of the embodiments described herein, the orientation of the VRM board can be substantially at a right angle to the main board. Substantially at a right angle means that the orientation of the VRM board is within a reasonable variance from a right angle without significantly impacting use of the mother board. Alternatively, the VRM board can be oriented at other angles including in the ranges of 70°-80°, 60°-70°, 50°-60°and 40°-50°. These orientations can be achieved through the interconnect assembly or through the connection mechanism which couples the VRM board to the heat sink, the processor carrier or the mother board. Additionally, the VRM board can be mounted so that its plane is not parallel to the plane of the main board. 
     The second advantage is that the VR may now be placed in the same air-flow path as the microprocessor or main electronic device which typically has superior air-flow and thermal management as compared to other components in the electronic system design. The orientation may also be made to be in parallel with the fin array of the heatsink which has a further advantage for cross-flow thermal arrangements where the air is plenumed in a direction parallel to the fin orientation. In other words, the VRM PCB acts as another fin and can take advantage of the air-flow given to that region. An additional benefit is that by locating the VRM close or onto the heatsink, the VRM can take advantage of some of the mechanical retention features already built in for the heatsink to device retention. This can further reduce the solution cost. 
     Referring now to  FIG. 2 , the second embodiment of the present invention is shown in another side ‘end’ view similar to that shown in FIG.  1 A. In this embodiment the edge connector is shown connecting to a side of the interposer which is offset 90 degrees from the orientation shown in FIG.  1 . Right-angle VRM assembly  204  is similar to that shown in the previous embodiment except that now socket  112  has actuation mechanism  118  on side opposite to the edge card connector  210 . VRM assembly  204  is still connected to heat dissipating device  102  and secured through a fastener such as  106 . Flex circuit  208  egresses from bottom side of VRM board  203  and allows an easier connection to the interposer  216 . Construction of assembly  200  may be accomplished through a number of methods. One such method is to assemble right-angle VRM to heatsink  102  and then assemble the lid  154  of the electronic device to heatsink  102 . Typically, a retention and alignment mechanism is used to mechanically secure the heatsink  102  where the heatsink is held down to the socket  112  and/or the main board  116 . An alignment and retention feature may be added to allow connector  210  to be securely supported to aid in the connection to the interposer at the interposer/edge connector interface  226  without disrupting the mechanical assembly or the thermal interface  122 . Interposer  216  is usually securely fastened to the socket through the interconnect such as pin array  218 . 
       FIG. 3  shows another embodiment of the present invention which does not use an edge connection for the interconnect assembly and does not rely on any connection to the heatsink for mechanical connection. Right-angle VRM subassembly  304  is similar to those shown in the previous drawings. Subassembly  304  is secured to bracket  306  via fastener  309 . In turn, bracket  306  is secured to interposer  318  by fastener  315 . Fasteners  309  and  315  are preferably disconnectable to allow for replacement of the VRM assembly. Alternatively, the fasteners can be replaced with permanent connections. A flex circuit  308  is used to interconnect electrically power and signals from PCB  303  to interposer  318 . Bracket  306  is typically made of a material which is electrically conductive and may be used for returning currents to interfaces on VRM board  303  and interposer  318 . 
       FIG. 4  shows an enlarged view of Section A shown in FIG.  3 . Interfaces, such as  409  make electrical connection (typically ground) between interposer  318  and VRM PCB  303 . Although not shown, the pads may be contiguous strips which extend along the length of one side of the VRM board and/or the interposer. That is, one strip may be dedicated for power distribution and the other for ground return as well as other discrete pads may be dedicated for signal connections. Fastener elements  309 ,  408 , and  410  secure VRM assembly  404  to bracket  306  and retain flex circuit  308  as well while maintaining compression on contacts on flex circuit  308  such as  413 . Similarly fasteners  315 ,  418 , and  416  secure bracket  306  to interposer  318  while securing and aligning flex circuit  308  to interposer  318  and maintaining compression through contacts, such as  420 . Fastening elements  408  and  418  may be resilient and/or compliant to additionally control and maintain force on contacts  413  and  420 , respectively. 
       FIG. 5  is another embodiment of the present invention using a further interconnect assembly. Assembly  500  comprises a heatsink  502  which is attached to an electronic subassembly as described in previous embodiments. As shown in  FIG. 5  a bracket is used to secure VRM board  503  to interposer  514  electrically and mechanically. Note though that in this embodiment the bracket  510  is separably connected to both interposer  514  and right-angle VRM subassembly  504 . The bracket has an opposing sub-bracket  506  which helps to retain flex circuit  508  which resides between the two bracket components  506  and  510 . 
       FIG. 7  shows Section B from  FIG. 5  in more detail. The bracket  510  is mechanically attached through bracket portion  710  to bracket  506 . A spring-member  712  extends through bracket portion  710  and provides pressure on flex circuit  508  and contacts  707  and  714  thereof. The circuit  508  also extends through an appropriate opening in bracket portion  710 . VRM board  503  and interposer  514  have surface pads (not shown) which electrically connect to copper layers for power distribution (also not shown). In assembly, bracket subassembly  700  may be connected to either interposer  514  and then VRM PCB  503  or conversely. 
       FIG. 6  shows a top view of assembly  600  which comprises lid  154  and substrate  152  with interposer  514  mounted to socket  112  which is mounted to main board  116 , without the heatsink or other mechanical and electrical elements shown, with contact pads on its top surface. This arrangement can be used with any of the embodiments described herein. Contact pads  605 A through  605 X are located adjacent to an edge of the interposer  514 . The contact pads are inter-digitated power and ground contact pads for electrical connection between the VRM board and interposer  514 . Inter-digitated contacts are used for making low inductance connections. As an example, contact  605 A may be assigned as a power contact and contact  605 B assigned a ground contact or current return for power contact  605 A. This pattern may be duplicated across interposer  604  on a given side of the interposer as shown on the right side of interposer  514  in assembly  600 . Signals may also be connected between the interposer and one or more of the contact pads shown may be assigned to send signals between the VRM board and the interposer for power conditioning or other functions. The contact pads  605 A through  605 X do not represent the only quantity or type of contacts that may be used to conduct power and/or signals between the VRM board and interposer. Multiple rows of contacts—that is a duplicate set of contact pads on the interposer—less or more contacts, or non-interdigitated connections may be used as well which would not detract from the invention disclosed herein. 
       FIG. 8  shows an embodiment where the right-angle VRM is mounted into a portion of socket  816  and where an interconnect resides which is used to connect power and signals from the VRM PCB  803  to the interposer  820 . In this embodiment, the interconnect assembly is a portion of socket  816  and a connection. Note that no mechanical retention or alignment is shown attaching to heatsink  502  but this need not be so. A separate retention and alignment feature may be used to engage VRM subassembly  804  into socket  816 . Retention and alignment mechanisms for VRM&#39;s are well known in the state of the art and many mechanisms may be used without detracting from the present invention. 
     Section C from  FIG. 8  is shown in detail with the end cut-away in FIG.  9 . VRM board  803  is engaged into socket region  908  where chamfer  902  is used to lead-in VRM PCB  902  without damage. Connector  808  makes contact to surface pads  906  on PCB  803  which make electrical connection to layers internal to PCB  803  (not shown). Electrical connector  808  has an opposite end which makes electrical connection to pads  904  on the underside of interposer  820  which make electrical connection to layers within or on interposer  820 . Other methods of interconnection with this arrangement to the VRM are also possible which are not beyond the scope of this patent such as making electrical connection between the VRM and the main board through a connection system which is part of socket  816 . Additionally, a plurality of separate electrical connectors can be used. 
       FIG. 10  shows subassembly  1000  which can have most of the components described previously in the other embodiments with a further interconnect assembly. In this embodiment the interconnect assembly is mounted to VRM board  1003  which in turn mounts to surface pads, such as  1007  on the surface of interposer  1010 . An electrical connector  1008  mounted to VRM board  1003  has housing support  1006  which is used for mechanical alignment and retention of the connector to VRM board  1003 . Most embodiments would include a plurality of such electrical connectors. Connector  1008  is z-axis compressible. The lower end of the connector extends beyond the housing support  106 . When the VRM subassembly  1004  is inserted down upon the surface of the interposer  1010 , connector  1008  is compressed and makes electrical connection between VRM PCB  1003  and interposer  1010 . Section D is shown in more detail in FIG.  11 . VRM board  1003  has connector  1008  which is retained through mechanical housing  1006  which has region  1104  where connector  1008  is retained. When the right-angle VRM subassembly is brought down in a z-axis fashion to top surface of interposer  1010 , connector  1008  is compressed and makes electrical connection to surface pad  1110 . 
     The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.