PATENT DOCUMENT

Publication Number: US-9820373-B2
Application Number: US-201414503067-A
Country: US
Kind Code: B2

Title: Thermal solutions for system-in-package assemblies in portable electronic devices

Abstract:
A compact portable electronic device packaged into a System-in-Package assembly and thermal solutions for the device is disclosed. The compact portable electronic device can be assembled into a single package to reduce size and enhance form factor. Several tens or hundreds of components including multiple dies, passive components, mechanical or optical components can be packaged into a single system on a printed circuit board. One or more of the components can dissipate a lot of power resulting in the generation of excess heat. To remove the excess heat, the device can include one or more thermal solutions such as internal thermal plugs, heat spreaders, internal embedded heat sinks, and/or external heat sinks. In some examples, the thermal solutions can dissipate heat via conduction to the bottom of the substrate or via convection to the top of the system or a combination of both.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a substrate; and 
 a system in package assembly comprising:
 a plurality of components, the plurality of components including a first component including a first surface mounted to the substrate and a second surface, and 
 one or more thermal plugs including a first thermal plug mounted to the second surface of the first component, wherein a first surface of the first thermal plug directly contacts the second surface of the first component, and a second surface of the first thermal plug directly contacts a shielding layer, 
 the shielding layer dissipating and spreading heat by the first thermal plug to the substrate, wherein the shielding layer is electrically connected to ground. 
 
 
     
     
       2. The device of  claim 1 , wherein a size of the one or more thermal plugs is same as a size of the plurality of components. 
     
     
       3. The device of  claim 1 , wherein at least one of the one or more thermal plugs is electrically coupled to a ground or ground plane. 
     
     
       4. The device of  claim 1 , further comprising an insulating layer, the insulating layer coating sides of the plurality of components and the one or more thermal plugs. 
     
     
       5. The device of  claim 4 , further comprising a plurality of trenches formed in the insulating layer, wherein a width of each of the plurality of trenches is between 10-100 microns. 
     
     
       6. The device of  claim 1 , wherein the shielding layer and at least one of the one or more thermal plugs is electrically coupled. 
     
     
       7. The device of  claim 1 , wherein the shielding layer is electrically coupled to a ground or ground plane. 
     
     
       8. A method for forming an electronic device, comprising:
 forming a substrate; and 
 forming a system in package assembly, comprising:
 mounting a first surface of a plurality of components to the substrate, the plurality of components including a first component, 
 mounting one or more thermal plugs including mounting a first thermal plug to a second surface of first component, wherein a first surface of the first thermal plug directly contacts a second surface of the first component, and a second surface of the first thermal plug directly contacts a shielding layer, 
 forming the shielding layer, the shielding layer configured to dissipate and spread heat by first thermal plug to the substrate, 
 electrically connecting the shielding layer to ground. 
 
 
     
     
       9. The method of  claim 8 , further comprising:
 forming an insulating layer, the insulating layer coating sides of the plurality of components and the one or more thermal plugs. 
 
     
     
       10. The method of  claim 9 , wherein the insulating layer is formed using at least one of a tape-assisted transfer molding process, lapping, polishing, and etching.

Description:
FIELD 
     This relates generally to dissipating thermal heat and, more particularly, to effective thermal solutions for components in System-In-Package assemblies in compact portable electronic devices. 
     BACKGROUND 
     Compact portable electronic devices are becoming increasingly popular. Examples of compact portable electronic devices include laptop computers, tablet computing devices, cellular telephones, media players, gaming devices, handheld devices, miniature devices such as pendant and wristwatch devices, and other devices. It is generally desirable to reduce the size and enhance the form factor of compact portable electronic devices. One way to reduce size and enhance form factor is to integrate circuitry into a System-in-Package assembly. In a System-in-Package assembly, hundreds of electrical components including multiple dies, passive components, mechanical or optical components can be packaged in a single system on a printed circuit board. 
     One or more of the components in the System-in-Package assembly can dissipate a lot of power. This power dissipation can result in the generation of heat. With advances in computing speed and complexity, the issue can be further compounded. Without an effective thermal solution, excess heat can lead to performance degradation and decreased long-term reliability of the components. 
     SUMMARY 
     This relates to a compact portable electronic device and thermal solutions for the device packaged into a System-in-Package assembly. The compact portable electronic device can be assembled into a single package to reduce size and enhance form factor. Several tens or hundreds of components including multiple dies, passive components, mechanical or optical components can be packaged into a single system on a printed circuit board. One or more of the components can dissipate a lot of power resulting in the generation of excess heat. To remove the excess heat, the device can include one or more thermal solutions such as internal thermal plugs, heat spreaders, internal embedded heat sinks, and/or external heat sinks. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1D  illustrate systems in which examples of the disclosure can be implemented. 
         FIG. 2A  illustrates a perspective view of an exemplary portable electronic device. 
         FIG. 2B  illustrates a block diagram of an exemplary portable electronic device. 
         FIG. 2C  illustrates a perspective view of an exemplary portable electronic device that includes components mounted on one or more printed circuit boards. 
         FIG. 3A  illustrates an exemplary block diagram of an exemplary portable electronic device assembled into a SiP assembly according to examples of the disclosure. 
         FIG. 3B  illustrates a perspective view of an exemplary portable electronic device with components and circuitry integrated into a SiP assembly according to examples of the disclosure. 
         FIG. 4A  illustrates a cross-sectional view of an exemplary portable electronic device assembled into a SiP assembly. 
         FIG. 4B  illustrates a process for forming an exemplary portable device assembled into a SiP assembly. 
         FIG. 5  illustrates a cross-sectional view of an exemplary portable electronic device assembled into a SiP assembly using pins or balls to dissipate heat. 
         FIGS. 6A-6C  illustrate cross-sectional views of an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs to dissipate heat according to examples of the disclosure. 
         FIG. 6D  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs to dissipate heat according to examples of the disclosure. 
         FIGS. 7A-7D  illustrate cross-sectional views of an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs and a heat spreader to dissipate heat according to examples of the disclosure. 
         FIG. 7E  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs and a heat spreader to dissipate heat according to examples of the disclosure. 
         FIGS. 8A-8D  illustrate cross-sectional views of an exemplary portable electronic device assembled into a SiP assembly using one or more heat sinks and a heat spreader to dissipate heat according to examples of the disclosure. 
         FIG. 8E  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using one or more heat sinks and a heat spreader to dissipate heat according to examples of the disclosure. 
         FIGS. 9A-9E  illustrate cross-sectional views of an exemplary portable electronic device assembled into a SiP assembly using an external heat sink to dissipate heat according to examples of the disclosure. 
         FIG. 9F  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using an external heat sink to dissipate heat according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of examples, reference is made to the accompanying drawings in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the various examples. 
     This relates to thermal solutions for electrical, mechanical, and optical components and subsystems in a portable electronic device assembled using System-in-Package (SiP) technology. Thermal solutions can include, but are not limited to, thermal plugs, heat spreaders, internal embedded heat sinks, and external heat sinks. The thermal solutions can allow heat generated internally by “hot” components to be conducted or dissipated out. Hot components can include transceivers, memory circuits, and other circuitry formed from one or more discrete components such as transistors, amplifiers, inductors, capacitors, resistors, switches, etc. The thermal solutions can dissipate heat via conduction to the bottom of the substrate or via convection to the top of the system or a combination of both. 
     In recent years, portable electronic devices such as laptops, tablet computing devices, cellular telephones, media players, gaming devices, handheld devices, miniature devices, etc., have become small, light and powerful. One factor contributing to this reduction in size can be attributed to the manufacturer&#39;s ability to fabricate various components in these devices in smaller and smaller sizes while, in some cases, increasing the power and/or operating speed of such components. Another factor contributing to the reduction in size is that from a visual standpoint, users often find compact and sleek designs of portable electronic devices more aesthetically appealing and thus, demand compact and sleek designs. The trend for smaller, lighter, more compact and powerful devices presents continuing challenges in the design of portable electronic devices and its associated components. 
     One area that can enable small and compact devices is internal packaging. A particular device can have a desired form factor and functionality. The desired form factor can determine a size of the housing in which components that provide the desired functionality are packaged into. The internal packaging design can involve minimizing any unused dead space that does not contribute in some way to the functioning of the device while still fitting the needed components in an allotted space dictated by the form factor. 
     Electrical, mechanical, and optical components can be included in one or more subsystems and packaged using the System-in-Package (SiP) technology. SiP is a functional system assembled into a single package. Several tens or hundreds of components including multiple dies, passive components, mechanical or optical components can be packaged in a single system on a printed circuit board (PCB). The PCB can be formed from rigid PCB materials such as fiberglass-filled epoxy (e.g., FR4), flexible printed circuits (e.g., printed circuits formed from flexible sheets of polymer such as polyimide), and rigid flex circuits (e.g., printed circuits that contain both rigid portions and flexible tails). PCBs on which components such as integrated circuit components and discrete components are mounted can sometimes be referred to as main logic boards (MLBs). The components can be mounted on the PCB using solder or other suitable mounting arrangements. For example, the components can be surface-mount technology (SMT) components that are mounted directly onto a PCB. SiP can lead to higher volumetric efficiency, superior reliability, higher performance, and smaller form factor. 
       FIGS. 1A-1D  illustrate systems in which examples of the disclosure can be implemented.  FIG. 1A  illustrates an exemplary mobile telephone  136  that includes a display screen  124  packaged in housing  150 .  FIG. 1B  illustrates an exemplary digital media player  140  that includes a display screen  126  packaged in housing  160 .  FIG. 1C  illustrates an exemplary personal computer  144  that includes a display screen  128  packaged in housing  170 .  FIG. 1D  illustrates an exemplary tablet computing device  148  that includes a display screen  130  packaged in housing  180 . The one or more thermal solutions according to the disclosure can be implemented in one or more of the illustrated systems. 
       FIG. 2A  illustrates a perspective view of an exemplary portable electronic device. Device  200  can include a housing  210  with an opening  208 . A display  204  surrounded by a frame can be positioned within opening  208 . Display circuitry for the display  204  can be located within housing  210 , such as directly below display  204 . The positioning of the display circuitry can affect the internal spaces that are available within housing  210 . 
     A touch screen can be associated with display  204 . Circuitry associated with the touch screen, such as a touch screen controller, can be located within housing  210 . Housing  210  can be formed from any material such as metal, plastic, fiber-composite materials, carbon fiber materials, glass, ceramics, or combinations of these materials. Housing  210  can be formed from a single piece of machined metal (e.g., using a unibody-type construction) or can be formed from multiple structures that are attached together such as an internal housing frame, a bezel or band structure, housing sidewalls, planar housing wall members, etc. Display  204  can be sealed via a cover glass or cover material  206 . One or more input buttons, such as input button  214 , can be positioned in an opening of cover glass  206 . Detection circuitry associated with input button  214  can be located within housing  210 . In some examples, input button  214  can be used to return device  200  to a particular state, such as a home state. 
     A number of input/output mechanisms can be located around the edges of housing  210 . For instance, a data/power connector  218  and audio jack  216  can be located on a bottom edge of housing  210 , and a power switch  220  can be located on a top edge of housing  210 . Housing  210  can also include openings for speakers and/or microphones. Circuitry supporting these components can be packaged internally within housing  210 . The circuitry can be embodied on various circuit boards or on a single circuit board, such as in a SiP assembly, disposed within housing  210 . 
     An exemplary block diagram of device  200  is shown in  FIG. 2B . The components described above can be controlled by a processor on a MLB  255 . Various internal connections can be provided that allow data to move between MLB  255  and the various components. The routing of internal data connections can depend on how various components are packaged including where MLB  255  is positioned within housing  210  and available internal pathways that result after positioning of the various internal device components. 
     In regards to data connections, MLB  255  can be coupled to a display controller  260 , which can be coupled to display  204  (shown in  FIG. 2A ). Further, MLB  255  can be coupled to audio components, such as a speaker, an audio jack  216 , and a microphone or associated audio circuitry  264  including an audio codec. Further, MLB  255  can be coupled to the various input devices, such as touchscreen  222  coupled to a touchscreen controller  262 , input button circuitry, and power switch circuitry. In addition, MLB  255  can be coupled to various data interfaces, such as wireless controller  256 , antenna  266 , and data/power connector  218 , that allow it to receive and send external data. 
     Besides data connections, many internal device components can receive power from an internal power source, such as battery  230 . For instance, battery  230  can be coupled to MLB  255 , display  204 , display controller  260 , touchscreen  222 , touchscreen controller  262 , and data/power connector  218 . Like the data connections, routing of the power connections can depend on the positioning of the various internal device components, such as battery  230  and the available internal pathways within housing  210 . 
       FIG. 2C  illustrates a perspective view of an exemplary portable electronic device that includes components mounted on one or more PCBs. Device  200  can include housing  210  and multiple components such as wireless controller  256 , antenna  266 , audio circuitry  264 , display controller  260 , and touch controller  262  mounted on one or more circuit boards such as PCB  224  within housing  210 . Components can include integrated circuits such as general purpose processing units, application-specific integrated circuits, radio-frequency components such as wireless transceivers, clock generation and distribution circuits, or other components such as discrete components. PCB  224  can be a MLB or another type of logic board. 
     Components can be grouped and arranged into subsystems based on their functionality. Example subsystems can include, but are not limited to, wireless subsystem  240 , audio subsystem  242 , touch subsystem  244 , and display subsystem  246 . One or more of the subsystems can produce and/or be susceptible to electromagnetic interference (EMI). Shielding structures can be used between and/or around one or more subsystems to help reduce EMI from reaching one or more components. 
     To reduce the packaging size and the size of these compact portable electronic devices, components and circuitry can be integrated into a SiP assembly.  FIG. 3A  illustrates a block diagram of an exemplary portable electronic device assembled into a SiP assembly according to examples of the disclosure. Device  300  can include various circuitry that can be packaged into a single package or SiP assembly. Several tens or hundreds of electronic components including multiple dies, passive components, mechanical or optical components can be packaged in a single system on a PCB. Antenna  366 , audio jack  316 , volume switch  312 , data/power connector  318 , wireless controller  356 , audio circuitry  364 , input button  314 , display controller  360 , touchscreen controller  362 , and power switch  320  can be included on MLB  355 . MLB  355  can be coupled to display  304 , touchscreen  322 , and battery  330 . 
       FIG. 3B  illustrates a perspective view of an exemplary portable electronic device with components and circuitry integrated into a SiP assembly according to examples of the disclosure. Device  300  can include housing  310 . Components and circuitry can be mounted and integrated on a PCB  324 . Components can include wireless controller  356  and antenna  366  in wireless subsystem  340 , input button  314  in I/O subsystem  350 , audio jack  316 , audio circuitry  364 , and volume switch  312  in audio subsystem  342 , display controller  360  in display subsystem  346 , touchscreen controller  362  in touch subsystem  344 , power switch  320  in power subsystem  348 , and components  382 - 392  in subsystem  352 . By integrating the components and circuitry into a SiP assembly, the size of the device can be reduced and/or the number of components can be increased. 
     In some examples, one or more of the components can dissipate a lot of power. This power dissipation can result in the generation of heat that may need to be conducted away for better device performance and long-term reliability of the components.  FIG. 4A  illustrates a cross-sectional view of an exemplary portable electronic device assembled into a SiP assembly. Components  482 ,  484 , and  486  can be mounted or disposed on PCB  424  using any mounting technique. To prevent internal and/or external interference, shielding structures can be disposed between one or more components. Shielding structures can include an insulating layer  476  and a shielding layer  478 . 
     Insulating layer  476  can be used to prevent electrical shorting between shielding layer  478  and any conductive materials on PCB  424  (e.g., conductive portions of components  482 ,  484 , and  486 ). Insulating layer  476  can be formed from epoxy, over-mold materials, under-fill materials, heat shrink jackets, acrylic materials, dielectric materials, thermoset materials, thermoplastics, rubbers, plastics, or other desirable materials that provide electrical insulation. 
     Shielding layer  478  can be formed on insulating layer  476  and/or in trenches  430  to shield the underlying components from EMI. Shielding layer  478  can include conductive materials such as silver paint, platinum paint, solder, metals such as copper or aluminum, metal alloys such as nickel-iron alloys, conductive adhesives, or other materials suitable for electromagnetic shielding. Shielding layer  478  can be formed in various configurations including walls, fences, sheets or layers, combinations of these configurations, or other desired configurations. 
     PCB  424  can include metal traces  442  and ground plane  446 . Shielding layer  478  can couple to metal traces  442  and ground plane  446  to form shielding structures that enclose each subsystem and can help protect components  482 ,  484 , and  486  from EMI (e.g., interference from external sources or internally between components of different subsystems). In some examples, metal traces  442  can be formed from conductive materials that help protect PCB  424  from cutting tools. For example, metal traces  442  can reflect lasers emitted by laser cutting tools used for forming trenches  430 . 
       FIG. 4B  illustrates a process for forming an exemplary portable device assembled into a SiP assembly. Process flow  450  can include providing a substrate or PCB  424  (step  452 ). Components  482 ,  484 , and  486  can be mounted on a surface of PCB  424  (step  454 ). Insulating layer  476  can be formed using an injection process or deposition process (step  456 ). For the injection process, molding tools can be used to mold insulating materials to form insulating layer  476 , and the molded insulating layer  476  can be transferred to PCB  424 . Molding tools can include injection molding tools, sintering tools, matrix molding tools, compression molding tools, transfer molding tools, extrusion molding tools, and other tools suitable for molding insulating materials into a desired configuration. Molding tools can be used to form structures that define the shape and location of the subsystems. For the deposition process, deposition tools can be used to deposit insulating layer  476  at desired locations on PCB  424 . Deposition tools can include tools for injecting insulating materials (e.g., epoxy) into injection molding tools to form shielding structures. Deposition tools can also include thin-film deposition tools (e.g., chemical or physical vapor deposition tools) or other tools desirable for forming shielding structures. 
     In step  458 , subsystems can be formed and defined. Each subsystem can enclose its respective components, and can be formed either during the injection process as described above or by scribing or etching trenches  430  using a cutting source. When using the injection process, molding structures (not shown) can have holes through which insulating material can be injected into a space inside the molding structures. After the injection process (e.g., after the insulating material is injected and sufficiently cooled), the molding structures can be removed. The insulating material can be heated prior and/or during injection using heating tools. Heating tools can include oil-based heating tools, gas-based heating tools, electrical-based heating tools, or any other heating tools suitable for heating the insulating material. Heating tools can, if desired, be used to apply pressure to the insulating layer  476  during formation. In some examples, the insulating layer  476  can be pre-formed and then placed on PCB  424  on components  482 ,  484 , and  486 . When using a cutting source to define each subsystem, trenches  430  can be formed by cutting through insulating layer  476  using cutting tools to isolate subsystems. Cutting tools can include sawing tools, laser cutting tools, grinding tools, drilling tools, electrical discharge machining tools, or other machining or cutting tools suitable for cutting through insulating layer  476 . 
     In some examples, a width of trenches  430  can be minimized. A minimum trench width can be equal to the spacing required for neighboring components to be electrically isolated from one another while substantially filling up or occupying a board space, thereby reducing the board space or footprint required. For example, the width of trenches  430  can be about 10-100 μm. Small trench widths can lead to not only a reduced amount of required board space, but can also lead to enhanced aesthetic appeal and improved optical uniformity. 
     In step  460 , shielding layer  478  can be deposited. Shielding layer  478  can be a plating film or thin-film metal deposited using any number of techniques, such as chemical vapor deposition, physical vapor deposition, plating, printing, or spray processes. 
       FIG. 5  illustrates a cross-sectional view of an exemplary portable electronic device assembled into a SiP assembly using pins or balls to dissipate heat. Device  500  can include components  582 ,  584 , and  586  mounted on PCB  524 . Insulating layer  576  can be formed on and/or around components  582 ,  584 , and  586  using any of the deposition techniques discussed above. One or more trenches  530  can be formed between subsystems, and trenches  530  can be filled or coated with shielding layer  578 . Components  582  and  584  can be “hot” components that produce a lot of power and as a result, generate excess heat. Components  582  and  584  can be seated on an array of pins (or balls)  540 . Array of pins  540  can be, for example, a ball grid array (BGA). BGAs can be a type of surface-mount packaging that includes discrete leads. The discrete leads can contact PCB  524 , and can provide a heat path to transfer any heat generated by components  582  and  584  to PCB  524 . 
     Although the array of pins  540  can provide a means of dissipating internal heat out of components  582  and  584 , the heat can be transferred to PCB  524 . Due to components  582 ,  584 , and  586  being assembled into a single package (e.g., mounted on the same substrate or PCB  524 ), heat generated from one component can dissipate and affect neighboring components via the shared PCB  524 . For example, heat generated from component  584  can be transferred via the array of pins  540  to PCB  524 . However, PCB  524  can be in contact with component  586 . As a result, heat generated from component  584  can be transferred to component  586 , leading to component  586  becoming hot. 
       FIGS. 6A-6C  illustrate cross-sectional views of an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs to dissipate heat according to examples of the disclosure. Device  600  can include a substrate or PCB  624 , as shown in  FIG. 6A . Components  682 ,  684 , and  686  can be mounted or disposed on PCB  624  using any mounting technique and using any suitable mounting material such as solder. In some examples, one or more components such as component  684  can be mounted on a heat sink such as BGA  640 . As shown in  FIG. 6B , one or more thermal plugs such as thermal plugs  632  and  634  can be formed on one or more components such as components  682  and  684 . Thermal plugs  632  and  634  can be blocks made from metal, such as Copper or Steel, that can be pre-fabricated to be a same size as a corresponding component. In some examples, thermal plugs  632  and  634  can be a different size than a corresponding component. Thermal plugs  632  and  634  can be any shape or size including, but not limited to, circular or rectangular shapes. Thermal plugs  632  and  634  can be mounted or attached to components  682  and  684  using any suitable thermal adhesive material such as Indium. 
     As shown in  FIG. 6C , insulating layer  676  can be formed on and/or around components  682 ,  684 , and  686  and thermal plugs  632  and  634 . Insulating layer  676  can be an epoxy, over-mold material, under-fill material, heat shrink jacket, acrylic material, dielectric material, thermoset material, thermoplastic, rubber, plastic, or other desirable material that provides electrical insulation. In some examples, insulating layer  676  can be formed using insulating materials that are both electrically insulating and thermally conductive. For example, insulating material can include thermally conductive plastics, epoxy, or other thermally conductive materials. Insulating materials that are thermally conductive can be used to draw heat away from components  682 ,  684 , and  686 . In some examples, insulating layer  676  can be thermally conductive and can include electrically insulating filler particles. 
       FIG. 6D  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs to dissipate heat according to examples of the disclosure. Process  650  can include providing PCB  624  (step  652 ). In step  654 , components  682 ,  684 , and  686  can be mounted on PCB  624 . Step  654  can include attaching BGA  640  to component  684 . In some examples, BGA  640  can be attached to component  684  before mounting component  684  to PCB  624 . In some examples, BGA  640  can be attached to PCB  624  followed by attaching component  684  to BGA  640 . In step  656 , one or more thermal plugs such as thermal plugs  632  and  634  can be mounted on or attached to one or more components such as components  682  and  684 . In some examples, thermal plugs  632  and  634  can be attached to components  682  and  684  before components  682  and  684  are mounted to PCB  624 . 
     In step  658 , insulating layer  676  can be formed. In some examples, insulating layer  676  can be deposited using a deposition tool. In some examples, insulating material can be injected into a space inside a molding structure. In some examples, insulating layer  676  can be formed using a tape-assisted transfer molding process. The tape-assisted transfer molding process can be a process where certain areas are masked when the insulating material is injected. Once the injection is complete, a top surface of the masked areas can be flush with a top surface of insulating layer  676 . For example, as shown in  FIG. 6B , a top surface of thermal plug  634  can be masked during the tape-assisted transfer molding process. Insulating material can be injected and can form on thermal plug  632  and component  686  (as shown in  FIG. 6C ). However, since thermal plug  634  was masked, insulating layer  676  may not form on a top surface of thermal plug  634  leading to the top surface of thermal plug  634  being flush with a top surface of insulating layer  676 . 
       FIGS. 7A-7D  illustrate cross-sectional views and  FIG. 7E  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using one or more thermal plugs and a heat spreader to dissipate heat according to examples of the disclosure. Process  750  can include providing device  700  with a substrate or PCB  724  (step  752 ), as shown in  FIG. 7A . Components  782 ,  784 , and  786  can be mounted or disposed on PCB  724  using any mounting technique (step  754 ) and using any suitable mounting material such as solder. In some examples, one or more components such as component  784  can be mounted on an array of pins such as BGA  740 . 
     As shown in  FIG. 7B , one or more thermal plugs such as thermal plugs  732  and  734  can be attached to one or more components such as components  782  and  784  (step  756 ). Thermal plugs  732  and  734  can be one or more pre-fabricated blocks of metal such as Copper or Steel. Thermal plugs  732  and  734  can be any shape or size including, but not limited to, circular or rectangular shapes. In some examples, thermal plugs  732  and  734  can be a same size as components  782  and  784 . In some examples, thermal plugs  732  and  734  can be a different size than component  782  and  784 . Thermal plugs  732  and  734  can be mounted or attached to components  782  and  784  using any suitable thermal adhesive material such as Indium. 
     As shown in  FIG. 7C , insulating layer  776  can be formed on and/or around components  782 ,  784 , and  786  and thermal plugs  732  and  734  (step  758 ). Insulating layer  776  can be an epoxy, over-mold material, under-fill material, heat shrink jacket, acrylic material, dielectric material, thermoset material, thermoplastic, rubber, plastic, or other desirable material that provides electrical insulation. In some examples, insulating layer  776  can be formed using insulating materials that are electrically insulating and thermally conductive such as thermally conductive plastics, epoxy, or other thermally conductive materials. Insulating layer  776  can be formed using a tape-assisted transfer molding process. 
     The SiP assembly process can further include cutting or forming trenches  730  in insulating layer  776  between components or subsystems (step  760 ), as shown in  FIG. 7D . Trenches  730  can be formed to isolate and define subsystems and can be filled or walls can be coated using a shielding layer  778  (step  762 ). Shielding layer  778  can be made from any shielding material such as a plating film or a metallic paste. Exemplary materials for shielding layer  778  can include, but are not limited to, Copper, Nickel, and Aluminum. Shielding layer  778  can be formed using chemical vapor deposition, physical vapor deposition, electroless plating, or electrochemical plating techniques. 
     Shielding layer  778  can be multi-functional and can also function as a heat spreader. In some examples, shielding layer  778  can be a multilayer stack with at least one layer configured to shield EMI and at least one layer configured to spread heat. Shielding layer  778  can be coupled to a ground such as ground plane  746  through metal traces  744 . Shielding layer  778  can dissipate and spread heat transferred by thermal plugs  732  and  734  to PCB  724 . For example, heat generated by component  784  can be dissipated through thermal plug  734  attached to component  784 . Thermal plug  734  can be coupled to shielding layer  778 . Shielding layer  778  can act as a heat spreader, and heat can further dissipate through shielding layer  778 . Shielding layer  778  can be coupled to ground plane  746  through metal traces  744 . Heat from shielding layer  778  can transfer to ground plane  746 , and ground plane  746  can spread or disperse the heat throughout PCB  724 . In some examples, ground plane  746  can be coupled to a housing (such as housing  210  of  FIG. 2A ). 
     In some examples, shielding layer  778  can be touching or in electrical contact with one or more thermal plugs to enhance the effectiveness of the heat spreading functionality. A top surface of insulating layer  776  can be flush with one or more thermal plugs such as thermal plug  734 . To achieve a flush top surface, insulating layer  776  can undergo lapping, polishing, or dry etching to remove any excess material. In some examples, a flush top surface can be achieved using a tape-assisted transfer molding process. In some examples, shielding layer  778  can be electrically insulated from one or more thermal plugs. For example, shielding layer  778  and thermal plug  732  can be separated by an air gap or by insulating layer  776 . 
       FIGS. 8A-8D  illustrate cross-sectional views and  FIG. 8E  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using one or more heat sinks and a heat spreader to dissipate heat according to examples of the disclosure. Device  800  can include a PCB  824  provided in step  852  of process  850 . PCB  824  can include a ground plane  846  and metal traces  844 . As shown in  FIG. 8A , components  882 ,  884 , and  886  can be mounted on PCB  824  using any suitable mounting material such as solder (step  854 ). 
     As shown in  FIG. 8B , one or more thermal plugs such as thermal plug  832  can be attached to one or more components such as component  882  (step  856 ). In step  858 , one or more heat sinks such as heat sink  848  can be attached to one or more components such as component  884 . Heat sink  848  can be an internal embedded heat sink, and can be touching or attached to component  884  using a suitable thermal interface material. In some examples, heat sink  848  can attach to PCB  824  to create an additional heat conduction path to the substrate or PCB  824 . Heat sink  848  can be electrically coupled or touching metal traces  844 . In some examples, heat sink  848  can be bonded to PCB  824 . In some examples, step  856  and step  858  can be a single step, and thermal plug  832  and heat sink  848  can be attached at a same time. 
     As shown in  FIG. 8C , insulating layer  878  can be disposed on and/or around components  882 ,  884 , and  886 , thermal plug  832 , and heat sink  848  to prevent electrical shorting between the subsequently formed shielding layer  876  and any conductive materials on PCB  824  (e.g., conductive portions of components  882 ,  884 , and  886 ) (step  860 ). Any material that has sufficient insulating properties can be used for insulating layer  876 , and any number of deposition or molding processes can be used to form insulating layer  876 . In some examples, a top surface of insulating layer  876  and a top surface of thermal plug  832  and/or heat sink  848  can be flush. 
     In step  862 , one or more trenches  830  can be formed using a laser cutting source, for example (as shown in  FIG. 8D ). Trenches  830  can isolate components and define subsystems. A shielding layer  878  and/or heat spreader can be deposited to fill or coat the walls of trenches  830  and conformally cover insulating layer  876  (step  864 ). Shielding layer  876  can be any material that has a high density, high conductivity, and/or good corrosion resistance. Shielding layer  876  can be formed using any deposition tools such as physical vapor deposition, chemical vapor deposition, printing, or plating. In some examples, shielding layer  876  can electrically contact or touch one or more thermal plugs and/or one or more heat sinks. 
     In some examples, heat sink  848  can be attached to tall components (e.g., components with a height greater than a predetermined value), and thermal plug  832  can be attached to short components (e.g., components with a height less than a predetermined value). For example, component  884  can be a tall component or taller than component  882 , and heat sink  848  can be attached to component  884  while thermal plug  832  can be attached to component  882 . In some examples, heat sink  848  can be attached to short components, and thermal plug  832  can be attached to tall components. In some examples, heat sink  848  can be attached to components that have certain characteristics, and thermal plug  832  can be attached to components that exhibit other characteristics. For example, to prevent hot spots or non-uniform heat dispersion, heat sinks  848  can be dispersed throughout and thermal plugs  832  can be dispersed between heat sinks (e.g., heat sinks and thermal plugs can be arranged in an alternating pattern). 
       FIGS. 9A-9E  illustrate cross-sectional views and  FIG. 9F  illustrates a process for forming an exemplary portable electronic device assembled into a SiP assembly using an external heat sink to dissipate heat according to examples of the disclosure. As shown in  FIG. 9A , device  900  can include PCB  924  (step  952  in process  950 ). PCB  924  can include a ground plane  946  and metal traces  944 . Components  982 ,  984 , and  986  can be mounted or disposed on PCB  924  using any mounting technique and using any suitable mounting material such as solder (step  954 ). One or more components such as component  984  can be attached to a BGA  940 . As shown in  FIG. 9B , one or more thermal plugs and/or heat sinks such as heat sink  948  can be attached to one or more components such as component  984  (step  956 ). 
     In step  958 , insulating layer  976  can be disposed on and/or around components  982 ,  984 , and  986  and heat sink  948  (as shown in  FIG. 9C ). In some examples, one or more components such as component  982  can have a top surface that is flush with a top surface of insulating layer  976 . In step  960 , trenches  930  can be formed in insulating layer  976 . 
     As shown in  FIG. 9D , shielding layer  978  can be disposed on insulating layer  976  and can fill and/or cover the walls of trenches  930  (step  962 ). In step  964 , one or more areas of shielding layer  978  can be etched away to expose a top surface of one or more components such as component  982 . In some examples, top surface of component  982  can be exposed by masking the area during deposition of shielding layer  978 . In step  966 , an external heat sink  990  can be attached to the exposed top surface of component  982  (as shown in  FIG. 9E ). In some examples, external heat sink  990  can be electrically coupled to shielding layer  978 . Heat from component  982  can be dissipated through external heat sink  990  (e.g., convention through the top) or through PCB  924  via shielding layer  978  (e.g., conduction through the bottom) or both. 
     In some examples, an electronic device is disclosed. The electronic device may comprise: a substrate; and a system in package assembly comprising: a plurality of components, the plurality of components including a first surface mounted to the substrate and a second surface, and one or more heat conductors mounted to the second surface of at least one component, wherein at least one heat conductor is a thermal plug. Additionally or alternatively to one or more examples disclosed above, in other examples, the device further comprises: another heat conductor, wherein the another heat conductor is at least one of an internal heat sink and an external heat sink. Additionally or alternatively to one or more examples disclosed above, in other examples, the thermal plug is made from at least one of Copper and Steel. Additionally or alternatively to one or more examples disclosed above, in other examples, at least one of the heat conductors is electrically coupled to a ground or ground plane. Additionally or alternatively to one or more examples disclosed above, in other examples, the device further comprises: a heat sink mounted between the first surface of at least one of the plurality of components and the substrate. Additionally or alternatively to one or more examples disclosed above, in other examples, the device further comprises: a shielding structure, the shielding structure including an insulator and a shielding. Additionally or alternatively to one or more examples disclosed above, in other examples, the shielding is multifunctional and is configured as a heat spreader. Additionally or alternatively to one or more examples disclosed above, in other examples, the shielding and at least one heat conductor are electrically coupled. Additionally or alternatively to one or more examples disclosed above, in other examples, the shielding is electrically coupled to a ground or ground plane. Additionally or alternatively to one or more examples disclosed above, in other examples, the device further comprises: a plurality of trenches formed in the insulator, wherein a width of the plurality of trenches is between 10-100 microns. Additionally or alternatively to one or more examples disclosed above, in other examples, heat generated from one or more of the plurality of components is dissipated through conduction and convection. Additionally or alternatively to one or more examples disclosed above, in other examples, the one or more heat conductors includes a plurality of thermal plugs and a plurality of heat sinks. Additionally or alternatively to one or more examples disclosed above, in other examples, the plurality of thermals plugs and the plurality of heat sinks are arranged in an alternating pattern. 
     In some examples, a method for forming an electronic device is disclosed. The method may comprise: forming a substrate; and forming a system in package assembly, comprising: mounting a first surface of a plurality of components to the substrate, and mounting one or more heat conductors to a second surface of at least one of the plurality of components, wherein at least one of the one or more heat conductors is a thermal plug. Additionally or alternatively to one or more examples disclosed above, in other examples, the one or more heat conductors includes another heat conductor, the another heat conductor is at least one of an internal heat sink and an external heat sink. Additionally or alternatively to one or more examples disclosed above, in other examples, the method further comprises: mounting a heat sink between the first surface of at least one of the plurality of components and the substrate. Additionally or alternatively to one or more examples disclosed above, in other examples, the method further comprises: forming a shielding structure, wherein forming the shielding structure includes forming an insulator and forming a shielding. Additionally or alternatively to one or more examples disclosed above, in other examples, the insulator is formed using at least one of a tape-assisted transfer molding process, lapping, polishing, and etching. Additionally or alternatively to one or more examples disclosed above, in other examples, the one or more heat conductors includes a plurality of thermal plugs and a plurality of heat sinks. Additionally or alternatively to one or more examples disclosed above, in other examples, the one or more heat conductors includes a first set of heat conductors and a second set of heat conductors and mounting one or more heat conductors comprises: mounting the plurality of thermal plugs to the first set of heat conductors, the first set of heat conductors including the one or more heat conductors with a height below a predetermined value; and mounting the plurality of heat sinks to the second set of heat conductors, the second set of heat conductors including the one or more heat conductors with a height above the predetermined value. 
     While various examples have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Although examples have been fully described with reference to the accompanying drawings, the various diagrams can depict an example architecture or other configuration for this disclosure, which is done to aid in the understanding of the features and functionality that can be included in the disclosure. The disclosure is not restricted to the illustrated exemplary architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, although the disclosure is described above in terms of various examples and implementations, it should be understood that the various features and functionality described in one or more of the examples are not limited in their applicability to the particular example with which they are described. They instead can be applied alone or in some combination, to one or more of the other examples of the disclosure, whether or not such examples are described, whether or not such features are presented as being part of a described example. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described examples.

Metadata:
Filing Date: 20140930
Publication Date: 20171114
Grant Date: 20171114
Priority Date: 20140626
Inventors: PENNATHUR SHANKAR S.
RIBAS CARLOS A. S.
TEOMAN DENIZ
ENG MICHAEL
Assignee: APPLE INC
CPC Classifications: [{"code": "H01L23/4334", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/4334", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/3121", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L23/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/0002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/3128", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2224/16227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/15192", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/19105", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/3025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/0002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/3121", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/4334", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/303", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0212", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0203", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0203", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/3128", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/4334", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0212", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K3/303", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/0002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/3121", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/303", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0212", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/0203", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/0002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/3121", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L23/4334", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/15192", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/19105", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/3025", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 54932142