Abstract:
An electronic package for providing an increased density of electronic components in systems includes electronic components mounted on two surfaces of a substrate. Electrical coupling is provided by electrical contacts mounted with substantially the same arrangement and number on both surfaces of the substrate. Two conductive substrates having apertures are mounted adjacent and substantially parallel to the two component mounting surfaces such that the electrical contacts mounted on the two surfaces protrude through the apertures of the two conductive substrates. The two conductive substrates are coupled to one or more heat sinks to conduct heat away from the multiple electronic components contained between the conductive substrates. Multiple electronic packages can be coupled together to form a stacked electronic package by physically connecting the electrical contacts of the electronic packages.

Description:
FIELD  
         [0001]    This invention relates to electronics and, more particularly, to electronic packages.  
         BACKGROUND  
         [0002]    In modern electronic systems, electronic devices, such as resistors, capacitors, transistors, logic gates, and processors are formed on substrates fabricated from materials such as silicon, germanium, and gallium arsenide. These substrates are mounted directly on the surface of a system board or packaged in modules, such as ceramic or plastic modules, which are mounted on the surface of a system board.  
           [0003]    Several problems arise in modem electronic systems that follow this die-on-board or module-on-board packaging strategy. First, for dice or modules located at opposite ends of a system board, the transit-time for signals between the dice or modules can be unacceptably long. Second, dice or modules packaged together on a system board can overheat and cause the system to fail.  
           [0004]    One solution to the transit-time problem requires laying out the system board so that the modules or dice that communicate with one another are packaged adjacent to each other. Unfortunately, the communications architecture for some systems preclude this solution.  
           [0005]    One solution to the overheating problem requires using large fans to cool the system. Unfortunately, large fans are noisy and consume unacceptable amounts of power in some systems.  
           [0006]    For these and other reasons there is a need for the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1A shows a perspective view of an electronic package in accordance with one embodiment of the invention.  
         [0008]    [0008]FIG. 1B shows a cross-sectional view of the electronic package shown in FIG.  1 A taken along the line XX.  
         [0009]    [0009]FIG. 1C shows a block diagram of the one or more electronic components shown in FIG. 1B in accordance with one embodiment of the invention.  
         [0010]    [0010]FIGS. 1D and 1E show a top view and a bottom view, respectively, of the electronic package shown in FIG. 1B.  
         [0011]    [0011]FIG. 1F shows a cross-sectional view of an electronic package that includes the electronic package shown in FIG. 1B in accordance with an alternate embodiment of the invention.  
         [0012]    [0012]FIG. 2 shows a side view of a stacked electronic package in accordance with one embodiment of the invention.  
         [0013]    [0013]FIGS. 3A, 3B,  3 C, and  3 D show detailed illustrations of electrical contacts in accordance with alternate embodiments of the invention.  
         [0014]    [0014]FIG. 4 shows a flow diagram of a method for forming an electronic package in accordance with one embodiment of the invention.  
         [0015]    [0015]FIG. 5 shows an illustration of a computer system including the stacked electronic package shown in FIG. 2 in accordance with one embodiment of the invention. 
     
    
     DESCRIPTION  
       [0016]    In the following detailed description of the invention, reference is made to the accompanying drawings which form a part hereof, and in which are shown, by way of illustration, specific embodiments of the invention which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present invention. The following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.  
         [0017]    [0017]FIG. 1A shows a perspective view of an electronic package  100  in accordance with one embodiment of the invention.  
         [0018]    [0018]FIG. 1B shows a cross-sectional view of the electronic package  100  shown in FIG. 1A taken along the line XX. The electronic package  100  includes a substrate  102 , a first plurality of electrical contacts  104 ,  105 ,  106 , and  107 , and a second plurality of electrical contacts  109 ,  110 ,  111 , and  112 . The substrate  102  has a first component mounting surface  114  and a second component mounting surface  116 . The first plurality of electrical contacts  104 ,  105 ,  106 , and  107  is located on the first component mounting surface  114 . The second plurality of electrical contacts  109 ,  110 ,  111 , and  112  is located on the second component mounting surface  116 .  
         [0019]    The substrate  102  is not limited to being fabricated from a particular material. In one embodiment, the substrate  102  is a ceramic. In an alternate embodiment, the substrate  102  is an epoxy. In another alternate embodiment, the substrate  102  is a multilayer copper-clad bismaleimide triazine (BT) laminate. In still another alternate embodiment, the substrate  102  is a non-laminate BT printed circuit board.  
         [0020]    The first component mounting surface  114  and the second component mounting surface  116  provide surfaces for mounting electronic components. One or more electronic components  118  can be mounted on the first component mounting surface  114 , and one or more electronic components  120  can be mounted on the second component mounting surface  116 . The one or more electronic components  118  and  120  are not limited to a particular type of electronic component. Exemplary electronic components suitable for use in connection with electronic package  100  include active components, such as transistors, logic circuits, and amplifiers, passive components, such as resistors, capacitors, and inductors, and integrated circuit components, such as processors, amplifiers, and application specific integrated circuits.  
         [0021]    The one or more electronic components  118  and  120  are not limited to being mounted on the first component mounting surface  114  and the second component mounting surface  116  using a particular technology. The one or more electronic components  118  ane  120  can be directly mounted on the first component mounting surface  114  and the second component mounting surface  116  using surface mount technology. Alternately, the one or more electronic components  118  and  120  can be assembled into modules or packages, such as ceramic modules or dual-in-line-packages, and the modules or packages can be mounted on the first component mounting surface  114  and the second component mounting surface  116 .  
         [0022]    [0022]FIG. 1C shows a block diagram of the one or more electronic components  118  in accordance with one embodiment of the invention. The one or more electronic components  118  include a core circuit  122  coupled to one or more logic circuits  124 .  
         [0023]    The core circuit  122  includes circuits that are capable of sending, receiving, processing, and storing information. In one embodiment, the core circuit  122  is a processor. In an alternate embodiment, the core circuit  122  is a network processor. In another alternate embodiment, the core circuit  122  is a memory circuit.  
         [0024]    The one or more logic circuits  124  include circuits that perform functions such as shaping, modifying, or buffering electrical signals to assist the core circuit  122  in processing signals. In one embodiment, the one or more logic circuits  124  are field programmable gate arrays.  
         [0025]    Referring again to FIG. 1B, the one or more electronic components  120  can include circuits similar to the core circuit  122  (shown in FIG. 1C) and the one or more logic circuits  124  (shown in FIG. 1C).  
         [0026]    The first plurality of electrical contacts  104 ,  105 ,  106 , and  107  and the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  are electrically coupled to the one or more electronic components  118  and  120 . The first plurality of electrical contacts  104 ,  105 ,  106 , and  107  and the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  are not limited to particular types of electrical contacts. Embodiments of the first plurality of electronic contacts  104 ,  105 ,  106 , and  107  and the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  suitable for use in connection with the electronic package  100  are shown in FIGS. 3A, 3B,  3 C, and  3 D.  
         [0027]    [0027]FIGS. 1D and 1E show a top view and a bottom view, respectively, of the electronic package  100  shown in FIG. 1B. The first plurality of electrical contacts  104 ,  105 ,  106 ,  107  has a configuration that is substantially identical to the configuration of the second plurality of electrical contacts  109 ,  110 ,  111 , and  112 . A configuration of electrical contacts includes both the number of electrical contacts and the spatial arrangement of the electrical contacts. A first configuration of electrical contacts is substantially identical to a second configuration of electrical contacts, if the number of electrical contacts in the first configuration equals the number of electrical contacts in the second configuration, and the spatial arrangement of the electrical contacts in the first configuration is substantially identical to the spatial arrangement of the electrical contacts in the second configuration. The spatial arrangement of the electrical contacts in a first configuration is substantially identical to the spatial arrangement of the electrical contacts in a second configuration, if the spacing between the two contacts in each pair of electrical contacts in the first configuration is substantially identical to the spacing between the two contacts in the corresponding pair of electrical contacts in the second configuration. The spacing between two electrical contacts is the shortest distance between the two electrical contacts.  
         [0028]    [0028]FIG. 1F shows a cross-sectional view of an electronic package  130  that includes the electronic package  100  shown in FIG. 1B in accordance with an alternate embodiment of the invention. The electronic package  130  further includes a first conductive substrate  132 , a second conductive substrate  134 , heat sinks  136  and  138 , and thermally conductive materials  140  and  142 . The first conductive substrate  132  is mounted adjacent to the thermally conductive material  140  and substantially parallel to the first component mounting surface  114 . The second conductive substrate  134  is mounted adjacent to the thermally conductive material  142  and substantially parallel to the second component mounting surface  116 . The first conductive substrate  132  has edges  144  and  146 . The second conductive substrate  134  has edges  148  and  150 . The edges  144 ,  146 ,  148 , and  150  are substantially perpendicular to the first component mounting surface  114  and the second component mounting surface  116 . The heat sink  136  is thermally coupled to the first conductive substrate  132  at the edge  144  and to the second conductive substrate  134  at the edge  148 . The heat sink  138  is thermally coupled to the first conductive substrate  132  at the edge  146  and to the second conductive substrate  134  at the edge  150 . The thermally conductive material  140  thermally couples the substrate  102  and the one or more electronic components  118  to the first conductive substrate  132  and to the heat sinks  136  and  138 . The thermally conductive material  142  thermally couples the substrate  102  and the one or more electronic components  120  to the second conductive substrate  134  and to the heat sinks  136  and  138 .  
         [0029]    The first conductive substrate  132  includes apertures  152 ,  153 ,  154 , and  155 . Each of the apertures  152 ,  153 ,  154 , and  155  provides access to one of the first plurality of electrical contacts  104 ,  105 ,  106 , and  107 . In one embodiment, each of the apertures  152 ,  153 ,  154 , and  155  is a circular aperture. In an alternate embodiment, each of the apertures  152 ,  153 ,  154 , and  155  is a square aperture. The second conductive substrate  134  includes apertures  158 ,  159 ,  160 , and  161 . Each of the apertures  158 ,  159 ,  160  and  161  provides access to one of the second plurality of electrical contacts  109 ,  110 ,  111 , and  112 . In one embodiment, each of the apertures  158 ,  159 ,  160 , and  161  is a circular aperture. In an alternate embodiment, each of the apertures  158 ,  159 ,  160 ,  161  is a square aperture.  
         [0030]    The first conductive substrate  132  is not limited to a particular shape, and the second conductive substrate  134  is not limited to a particular shape. The shape of the first conductive substrate  132  and the shape of the second conductive substrate  134  are selected to efficiently and economically remove heat from the electronic package  130 . In one embodiment, the first conductive substrate  132  is a substantially rectangular conductive plate, and the second conductive substrate  134  is a substantially rectangular conductive plate. In an alternate embodiment, the first conductive substrate  132  is a substantially rectangular conductive plate, and the second conductive substrate  134  is a substantially circular conductive plate.  
         [0031]    The first conductive substrate  132  is not limited to being formed from a particular material. In one embodiment, the first conductive substrate  132  is formed from copper. In an alternate embodiment, the first conductive substrate  132  is formed from a nickel plate covered with a copper layer. In another alternate embodiment, the first conductive substrate  132  is formed from a nickel-tin plate covered with copper. In still another alternate embodiment, the first conductive substrate  132  is formed from a thermally conductive metal formed on a non-metallic substrate.  
         [0032]    The second conductive substrate  134  can be formed from the same material as the first conductive substrate  132  or from a different material. Forming the first conductive substrate  132  and the second conductive substrate  134  from different materials allows tailoring the thermal conductivity of the electronic package  130  to efficiently and economically remove heat from the one or more electronic components  118  and  120 . In one embodiment, the first conductive substrate  132  is formed from a first material having a first conductivity and the second conductive substrate  134  is formed from a second material having a second conductivity not equal to the first conductivity.  
         [0033]    The heat sinks  136  and  138  thermally couple heat generated at the first conductive substrate  132  and the second conductive substrate  134  to the ambient environment. In another embodiment, if the heat sinks  136  and  138  are unable to remove sufficient heat from the electronic package  130 , then one or more additional heat sinks (not shown) are thermally coupled to the first conductive substrate  132  and the second conductive substrate  134 . In still another embodiment, the heat sink  136  and the heat sink  138  are extended to form a continuous heat sink along the periphery of the first conductive substrate  132  and the second conductive substrate  134 .  
         [0034]    The thermally conductive materials  140  and  142  provide a path to conduct heat from the electronic components  118  and  120  and the component mounting surfaces  114  and  116  to the first conductive substrate  132  and the second conductive substrate  134 . In one embodiment, the thermally conductive materials  140  and  142  are an electrically nonconductive solid. In an alternate embodiment, the thermally conductive materials  140  and  142  are an electrically non-conductive gas. An exemplary gas suitable for use in connection with the electronic package  130  is air. In another alternate embodiment, the thermally conductive materials  140  and  142  are an electrically non-conductive liquid.  
         [0035]    One exemplary solid suitable for use in connection with the electronic package  130  is a composite of Al 2 O 3 . In one embodiment, an Al 2 O 3  powder of between about 20% and about 40% by volume when mixed with an epoxy resin is chemically or thermally polymerized to form the composite of Al 2 O 3 . Another exemplary solid, suitable for use in connection with the electronic package  130 , is a composite mixture of a graphite powder and silicon oxide. In one embodiment, a graphite powder of between about 3% and about 5% by volume and silicon oxide of between about 15% and about 35% by volume when mixed with an epoxy resin is chemically or thermally polymerized to form the composite mixture of graphite powder and silicon dioxide. Another exemplary solid suitable for use in connection with the electronic package  130  is a silicon paste. In one embodiment, silicon dioxide is mixed with a silicon oil gel to form the silicon paste. Another exemplary solid suitable for use in connection with the electronic package  130  is a ceramic.  
         [0036]    During the operation of the electronic package  130 , the one or more electronic components  118  and the one or more electronic components  120  generate heat. The heat generated by the one or more electronic components  118  flows from the one or more electronic components  118  through the thermally conductive material  140  to the first conductive substrate  132 . The heat flows from the outer surface of the first conductive substrate  132  into the ambient environment, from the edge  144  of the first conductive substrate  132  to the heat sink  136 , and from the edge  146  of the first conductive substrate  132  to the heat sink  138 . The heat flows from the heat sinks  136  and  138  to the ambient environment.  
         [0037]    The heat generated by the one or more electronic components  120  flows from the one or more electronic components  120  through the thermally conductive material  142  to the second conductive substrate  134 . The heat flows from the outer surface of the second conductive substrate  134  into the ambient environment, from the edge  148  of the second conductive substrate  134  to the heat sink  136 , and from the edge  150  of the second conductive substrate  134  to the heat sink  138 . The heat flows from the heat sinks  136  and  138  to the ambient environment.  
         [0038]    [0038]FIG. 2 shows side view of a stacked electronic package  200  in accordance with one embodiment of the invention. The stacked electronic package  200  includes a first electronic package  202 , a second electronic package  204 , and a third electronic package  206 . The first electronic package  202  includes the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  (also shown in FIG. 1B). The second electronic package  204  includes the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  and the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  (also shown in FIG. 1B). The third electronic package  206  includes the second plurality of electrical contacts  109 ,  110 ,  111 , and  112 .  
         [0039]    As shown in FIG. 2, the third electronic package  206  is stacked on the second electronic package  204  (the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  of the third electronic package  206  are aligned and electrically coupled to the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  of the second electronic package  204 ), and the second electronic package  204  is stacked on the first electronic package  202  (the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  of the second electronic package  204  are aligned and electrically coupled to the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  of the first electronic package  202 ). Stacking the first electronic package  202 , the second electronic package  204 , and the third electronic package  206 , as shown in FIG. 2, results in the first electronic package  202  and the third electronic package  206  being electrically coupled to the second electronic package  204 .  
         [0040]    The electrical coupling of the first electronic package  202 , the second electronic package  204 , and the third electronic package  206  permits the routing of electrical signals to electronic components (not shown) within the stacked electronic package  200 . For example, electronic signals generated in the first electronic package  202  can be routed to the third electronic package  206 .  
         [0041]    In an alternate embodiment, the first electronic package  202  includes the electronic package  100  (shown in FIG. 1A), the second electronic package  204  includes the electronic package  100 , and the third electronic package  206  includes the electronic package  100 .  
         [0042]    In another alternate embodiment, the first electronic package  202  includes the electronic package  130  (shown in FIG. 1F), the second electronic package  204  includes the electronic package  130 , and the third electronic package  206  includes the electronic package  130 .  
         [0043]    In still another alternate embodiment, the first electronic package  202  includes the electronic package  130 , the second electronic package  204  includes the electronic package  100 , and the third electronic package  206  includes the electronic package  130 .  
         [0044]    Connectors (not shown) can be added to the stacked electronic package  200  to provide for receiving and transmitting signals. Alternately, the electronic package  200  can include a wireless transceiver (not shown) for transmitting and receiving signals.  
         [0045]    In operation, the one or more electronic components  118  and  120  (shown in FIGS. 1B and 1F) included in the stacked electronic package  200  produce heat. For embodiments of the stacked electronic package  200  that include electronic package  100 , the heat is removed from the stacked electronic package  200  primarily by convection. For embodiments of the stacked electronic package  200  that include the electronic package  130 , the heat is removed from the stacked electronic package  200  as described above for the electronic package  130 .  
         [0046]    Those skilled in the art will appreciate that the embodiment shown in FIG. 2 does not limit the present invention to a three package stack. Embodiments of the invention including any number of stacked electronic packages fall within the scope of the invention.  
         [0047]    [0047]FIGS. 3A, 3B,  3 C, and  3 D show detailed illustrations of electrical contacts  301 ,  302 ,  303 , and  304  in accordance with alternate embodiments of the invention. The electrical contacts  301 ,  302 ,  303 , and  304  are fabricated from a conductive material such as gold, copper, or silver.  
         [0048]    Each of the electrical contacts  301 ,  302 ,  303 , and  304  includes a base  306 , a body  308  and a tip  310 . The base  306  provides a surface for mounting each of the electrical contact  301 ,  302 ,  303 , and  304  on a first substrate mounting surface  114  (shown in FIGS. 1B and 1F) or a second substrate mounting surface  116  (shown in FIGS. 1B and 1F). In one embodiment, the base  306  is a substantially circular plate. In an alternate embodiment, the base  306  is a substantially square plate.  
         [0049]    The body  308  electrically couples the base  306  to the tip  310 . In one embodiment, the body  308  has a substantially cylindrical shape. In an alternate embodiment, the body  308  has a substantially square shape. In another alternate embodiment, the body  308  includes a spring  312 , a ball  314 , and a hollow containment element  316 , as shown in FIG. 3D. The ball  314  is spring-loaded in the hollow containment element  316 , as shown in FIG. 3D. The curved end  318  of the hollow containment element  316  is located opposite from the base  306  such that the movement of the ball  314  is restricted. Only a portion of the ball  314  extends out of the hollow containment element  316 . The tension of the spring  312  is selected to be sufficient to supply a force to maintain a portion of the ball  314  outside the hollow containment element  316  when the ball  314  is pressed into contact with the tip  310  of the electrical contact  303 .  
         [0050]    The tip  310  provides a mating surface for electrically coupling two of the electrical contacts  301 ,  302 ,  303 , and  304  together. In one embodiment, the tip  310  is a substantially concave shape (shown in FIG. 3A). In an alternate embodiment, the tip  310  is a substantially convex shape (shown in FIG. 3B). In another alternate embodiment, the tip  310  is substantially flat (shown in FIG. 3C). In still another alternate embodiment, the tip  310  is the surface of a substantially spherical ball (shown in FIG. 3D). The tip  310 , to provide good electrical contact, has a gold or gold alloy surface. In one embodiment, the tip is gold coated kovar.  
         [0051]    Each of the electrical contacts  301 ,  302 ,  303 , and  304  is suitable for use in connection with the electronic package  100  (shown in FIG. 1B), the electronic package  130  (shown in FIG. 1F), and the stacked electronic package  200  (shown in FIG. 2). In one embodiment, each of the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  (shown in FIGS. 1B and 1F) is the electrical contact  301 , and each of the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  (shown in FIGS. 1B and 1F) is the electrical contact  301 . In an alternate embodiment, each of the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  is the electrical contact  301 , and each of the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  is the electrical contact  302 . In another alternate embodiment, each of the first plurality of electrical contacts  104 ,  105 ,  106 , and  107  is the electrical contact  303 , and each of the second plurality of electrical contacts  109 ,  110 ,  111 , and  112  is the electrical contact  304 .  
         [0052]    [0052]FIG. 4 shows a flow diagram of a method  400  for forming an electronic package  130  (shown in FIG. 1F) in accordance with one embodiment of the invention. The method  400  includes mounting a pair of conductive substrates substantially parallel to a substrate (block  402 ), mounting one or more heat sinks to contact one or more edges of the pair of conductive substrates (block  404 ), and introducing a non-gaseous, thermally conductive material between the pair of conductive substrates and the substrate (block  406 ). In an alternate embodiment, introducing a non-gaseous, thermally conductive material between the pair of conductive substrates and the substrate includes injecting a ceramic material between the pair of conductive substrates and the substrate. In another alternate embodiment, the alternate embodiment of the method  400  that includes injecting a ceramic material between the pair of conductive substrates, further includes mounting a first plurality of electrical contacts on a first component mounting surface of the substrate and mounting a second plurality of electrical contacts on a second component mounting surface of the substrate.  
         [0053]    [0053]FIG. 5 shows an illustration of a computer system  500  including the stacked electronic package  200  shown in FIG. 1F in accordance with one embodiment of the invention. The computer system  500  includes a system board  502 , a processor  504 , a keyboard  508 , a mouse  510 , a display  512 , and the stacked electronic package  200 . The system board  502  provides conductive paths to couple the processor  504  to the keyboard  508 , the mouse  510 , the display  512 , and the stacked electronic package  200 .  
         [0054]    Although specific embodiments have been described and illustrated herein, it will be appreciated by those skilled in the art, having the benefit of the present disclosure, that any arrangement which is intended to achieve the same purpose may be substituted for a specific embodiment shown. This application is intended to cover any adaptations or variations of embodiments of the present invention. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.