PATENT DOCUMENT

Publication Number: US-10292291-B2
Application Number: US-201815937723-A
Country: US
Kind Code: B2

Title: Compact media player

Abstract:
An electronic device such as a media player is formed from electrical components such as integrated circuits, buttons, and a battery. Electrical input-output port contacts are used to play audio and to convey digital signals. Electrical components for the device are mounted to a substrate. The components are encapsulated in an encapsulant and covered with an optional housing structure. The electrical input-output port contacts and portions of components such as buttons remain uncovered by encapsulant during the encapsulation process. Integrated circuits are entirely encapsulated with encapsulant. The integrated circuits are packaged or unpackaged integrated circuit die. The substrate is a printed circuit board or is an integrated circuit to which components are directly connected without any printed circuit boards interposed between the integrated circuit and the components.

Claims:
What is claimed is: 
     
       1. A portable electronic device, comprising:
 a substrate; 
 an integrated circuit mounted on the substrate, wherein the integrated circuit includes an audio circuit that produces audio signals; 
 a battery; and 
 an encapsulant that encapsulates the integrated circuit, the substrate, and the battery, wherein the encapsulant forms an external surface of the portable electronic device. 
 
     
     
       2. The portable electronic device defined in  claim 1 , wherein the substrate is a printed circuit board. 
     
     
       3. The portable electronic device defined in  claim 1 , wherein the battery is mounted on the substrate. 
     
     
       4. The portable electronic device defined in  claim 1 , further comprising a user-input component mounted on the substrate. 
     
     
       5. The portable electronic device defined in  claim 4 , wherein the user-input component is a touch-sensitive component. 
     
     
       6. The portable electronic device defined in  claim 1 , further comprising input-output port contacts formed on the substrate. 
     
     
       7. The portable electronic device defined in  claim 1 , further comprising a speaker. 
     
     
       8. The portable electronic device defined in  claim 1 , wherein the encapsulant forms an additional external surface of the portable electronic device in addition to the external surface of the portable electronic device. 
     
     
       9. The portable electronic device defined in  claim 8 , wherein the external surface and the additional external surface are orthogonal. 
     
     
       10. The portable electronic device defined in  claim 1 , wherein the encapsulant has an upper surface between first and second opposing side surfaces, wherein the upper surface forms the external surface of the portable electronic device, wherein the first side surface forms a first additional external surface of the portable electronic device, and wherein the second side surface forms a second additional external surface of the portable electronic device. 
     
     
       11. The portable electronic device defined in  claim 10 , wherein the substrate has first and second opposing surfaces, wherein the integrated circuit is mounted to the first surface of the substrate, and wherein the second surface of the substrate forms a third additional external surface of the portable electronic device. 
     
     
       12. A portable electronic device having an exterior, comprising:
 a substrate; 
 an integrated circuit mounted on the substrate; 
 a touch-sensitive component mounted on the substrate; and 
 an encapsulant that encapsulates the integrated circuit and the substrate without encapsulating the touch-sensitive component, wherein the encapsulant forms an external surface of the portable electronic device and wherein the touch-sensitive component is exposed to the exterior of the portable electronic device. 
 
     
     
       13. The portable electronic device defined in  claim 12 , wherein the touch-sensitive component is a button. 
     
     
       14. The portable electronic device defined in  claim 12 , wherein the integrated circuit includes an audio circuit that produces audio signals. 
     
     
       15. The portable electronic device defined in  claim 12 , wherein the integrated circuit includes a digital communications circuit that produces digital signals.

Description:
This application is a continuation of patent application Ser. No. 14/271,340, filed May 6, 2014, which is a division of patent application Ser. No. 12/628,967, filed Dec. 1, 2009, now U.S. Pat. No. 8,724,339, which are both hereby incorporated by reference herein in their entireties. This application claims the benefit of and claims priority to patent application Ser. No. 14/271,340, filed May 6, 2014, and patent application Ser. No. 12/628,967, filed Dec. 1, 2009, now U.S. Pat. No. 8,724,339. 
    
    
     BACKGROUND 
     This relates generally to electronic devices and, more particularly, to compact device constructions for electronic devices such as media players and media player accessories. 
     Electronic devices such as media players are often used in applications in which excessive size and weight is not desirable. For example, many users of media players listen to music while exercising or traveling. In situations such as these, it can be highly desirable to minimize the bulk of a media player. 
     In conventional media player designs, packaged integrated circuits and other components are mounted on a printed circuit board. The printed circuit board is mounted within a device housing using brackets and other mounting hardware. Conventional designs of this type are sufficiently durable to withstand normal handling, but can sometimes be more bulky than desired. 
     It would therefore be desirable to be able to provide compact arrangements for media players and other electronic devices. 
     SUMMARY 
     An electronic device such as a media player may be formed from electrical components such as integrated circuits, buttons, and a battery. A small form factor device may be implemented by eliminating some or all of the housing structures of traditional devices and component mounting structures. 
     With one suitable arrangement, an integrated circuit die is used as a substrate. Electrical components may be mounted directly to the integrated circuit die. With another suitable arrangement, a printed circuit board may serve as a mounting substrate. Packaged and unpackaged integrated circuit die and other electrical components may be mounted to the printed circuit board. 
     The electronic device may have input-output port electrical contacts. These contacts ma be used, for example, to play audio through an attached accessory or to convey digital signals to and from an attached computer. 
     During fabrication, the electrical components that are mounted to the substrate may be encapsulated in an encapsulant. The encapsulant may be formed from a dielectric such as epoxy, plastic, or other materials. When the encapsulant cures, the encapsulated electrical components are sealed off from the environment and are therefore not adversely affected by changes in humidity and other environmental factors. 
     A housing, such as a thin metal housing may be used to cover some or all of the encapsulant. Few or no gaps need be provided between the encapsulant and the walls of the housing. 
     During component encapsulation, the integrated circuits and other components such as discrete components may be entirely surrounded by encapsulant. Other structures such as portions of buttons and the electrical input-output port contacts may be left uncovered by the encapsulant. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of an illustrative electronic device such as a media player and a mating accessory such as a headset in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of an electronic device and accessory of the type shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  is a schematic circuit diagram of an electronic device such as a media player and a corresponding accessory in accordance with an embodiment of the present invention. 
         FIG. 4A  is a bottom perspective view of an illustrative electronic device in accordance with an embodiment of the present invention. 
         FIG. 4B  is a top perspective view of the illustrative electronic device of  FIG. 4A  in accordance with an embodiment of the present invention. 
         FIG. 5  is an exploded perspective view showing components in an illustrative electronic device in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of an illustrative electronic device before mounting of dome-switches and buttons in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative electronic device having a thin housing that helps to capture moving button members that are biased against dome switches in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of an illustrative electronic device showing how a battery and integrated circuit may be mounted on the opposite side of a substrate from a pair of dome switches and showing how the dome switches may be covered by flexible button structures in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of an illustrative electronic device showing how flip-chip mounting techniques may be used to mount integrated circuits directly on a printed circuit board that is encapsulated by an encapsulant that can serve as a device housing in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an illustrative electronic device showing how integrated circuits and a battery may be mounted to the opposite side of a printed circuit board from a set of dome-switch buttons and showing how the printed circuit board and components may be encapsulated in an encapsulant that can serve as a device housing in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of an illustrative electronic device showing how packaged integrated circuits may be mounted on a printed circuit board, covered with an encapsulant, and provided with an optional housing shell in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional partially exploded side view of an illustrative electronic device showing how contact leads may be embedded in encapsulant in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of an illustrative electronic device showing how multiple injection molding shots of injection-molded plastic may be used in encapsulating integrated circuits that have been directly mounted to a printed circuit board in a flip-chip configuration in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of an illustrative electronic device fashioned from a single integrated circuit die on which components such as switches and contacts leads have been formed in accordance with an embodiment of the present invention. 
         FIG. 15  is a flow chart of illustrative steps involved in forming an electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device and a corresponding accessory are shown in  FIG. 1 . Accessory  10  may be a headset or other electronic equipment. Electronic device  12  may be a media player or other electronic equipment. For clarity, arrangements in which electronic device  12  is a media player and in which accessory  10  is a pair of earbuds or other headphones are sometimes described herein as an example. This is, however, merely illustrative. Device  12  and accessory  10  may be any suitable electronic equipment. 
     The exploded perspective view of  FIG. 1  shows illustrative components of electronic device  12 . In some configurations of device  12  that are described herein, some or all of the components for device  12  are mounted directly on an integrated circuit die to save space. In this type of configuration, the die itself serves as a mounting substrate. Encapsulant and an optional housing shell may then be used to encase the mounted components. If desired, other substrates may be used for mounting components. For example, integrated circuits and discrete components may be mounted on a plastic support structure that is covered with conductive traces. In the example of  FIG. 1 , device  1  is formed using a substrate such as printed circuit board  16 . Printed circuit board  16  may be formed from a rigid printed circuit board material (e.g. fiberglass-filled epoxy) or flexible printed circuit board material (e.g., a polymer sheet such as a layer of polyimide). 
     Components such as components  32 , buttons  34 , and battery  18  may be electrically connected to printed circuit board  16 . For example, battery  18  may have battery terminals  30  that are electrically connected to battery contacts  28 . Traces on one or both sides of printed circuit board  16  may mate with corresponding electrical contacts on components such as components  32 , buttons  34 , etc. 
     Some or all of printed circuit board  16  may be coated with encapsulant (e.g., all or at least some of both the upper and lower sides of board  16  may be encapsulated). The encapsulant may be covered by an optional housing such as housing  14 . Housing  14  may, for example, have an opening such as opening  38  into which printed circuit board  16  and the encapsulant surrounding printed circuit board  16  may be inserted. If desired, printed circuit board  16  may be inserted into the interior of housing  14  and encapsulant may be injected into the gaps between printed circuit board  16  and the inner walls of housing  14 . Housing  14  may have holes such as holes  36  to accommodate buttons  34 . 
     Any suitable encapsulant may be used to encapsulate the circuitry of device  12 . For example, the circuitry of device  12  may be encapsulated using a dielectric such as epoxy. Other suitable materials that may be used as encapsulant include foam, silicone, plastic, glass, adhesive, combinations of these materials, etc. The encapsulant that is used to encase the circuitry of device  12  may form a rigid structure that helps adhere components to printed circuit board  16  or otherwise hold components in place. The encapsulant that is used may also help to block moisture and thereby prevent changes in humidity or other environmental factors from affecting the performance of the circuitry. Epoxy may be cured using thermal curing or ultraviolet light curing techniques. Thermoplastic encapsulants may be injection molded using an injection molding tool and hardened by cooling. In general, these curing techniques or other suitable techniques may be used in curing and hardening encapsulant. 
     One or more input-output ports may be formed in device  12 . For example, an input-output port may be formed by one or more electrical contacts such as electrical input-output port contacts  20 . Contacts  20  may be formed from traces of copper, copper plated with gold, or other conductive materials. There may be any suitable number of contacts (e.g., two, three, four or more, etc.). As shown in  FIG. 1 , contacts  20  may be formed on end portion  21  of device  12 . When printed circuit board  16  is inserted into housing  14 , end portion  21  may protrude out of hole  38 . This allows end portion  21  and contacts  20  to be inserted into hole  23  in accessory connector  22 . 
     Connector  22  may have contacts that mate with contacts  20  and that are coupled to wires in cable  24 . Cable  24  may be connected to components in accessory  10  such as speakers  26 , buttons, etc. 
     If desired, contacts  20  may have the shape and layout of contacts in a Universal Serial Bus (USB) plug. This allows end  21  to serve as a USB plug when plugging into a USB jack on a portable or desktop computer (as an example). A USB plug has power and ground pins and a pair of digital data pins. When plugged into connector  22 , the circuitry of device  12  can be reconfigured so that the digital data pins and the ground power pin operate as analog audio output pins for left and right audio. The positive power pin may or may not be used when device  12  is connected to accessory  10 , depending on whether or not the accessory contains circuitry that uses a power supply voltage supplied by battery  18 . 
     Components  32  may include packaged or unpackaged integrated circuits (i.e., packaged or unpackaged integrated circuit die), discrete components such as resistors, inductors, and capacitors (e.g., surface-mount technology components), components such as switches (see, e.g., switches  34 ), connector port components (e.g., USB connectors or other port connectors), etc. 
     A cross-sectional side view of device  12  when mated with connector  22  of accessory  10  is shown in  FIG. 2 . As shown in  FIG. 2 , when end  21  of device  12  is plugged into connector  22 , contact structures such as conductive metal prongs  40  make contact with corresponding contacts  20  in device  12 . Prongs  40  may be connected to electrical paths such as wires  25  using solder, welds, conductive adhesive, or crimp connections. Wires  25  may be connected to headphone speakers (i.e., earbud drivers). 
     A schematic circuit diagram of illustrative circuitry that may be used in device  12  is shown in  FIG. 3 . As shown in  FIG. 3 , device  12  may have storage  48  and processing circuitry  46 . Storage  48  may include volatile and nonvolatile memory (e.g., random-access memory, flash memory, solid state drives, hard drives, removable media, etc.). Processing circuitry  46  may be based on one or more microprocessors, microcontrollers, digital signal processors, application-specific integrated circuits, etc. Storage  48  may be used to store software code such as code that implements device functions for device  12 . Storage  48  may also be used to store media (e.g., song files, video files, etc.). During operation, processing circuitry  46  can run code such as the code that is stored in storage  48 . Using the general purpose resources of processing circuitry  46  and, if desired, dedicated hardwired resources in device  12 , processing circuitry  46  can implement functions such as media playback functions, user input-output command processing functions, etc. 
     Input-output circuitry  52  may be used to supply output to a user of device  12 . Input-output circuitry  52  may, for example, include output devices such as speakers, status indicator lights, buzzers, actuators to create vibrations, displays, etc. Input-output circuitry  52  may include audio circuitry  56  to supply audio output signals (e.g., analog right and left audio signals for corresponding right and left speakers in accessory  10  of  FIG. 1 ). Digital communications circuitry  58  may be used to support bidirectional communications over port  44 . Port  44  may include contacts  20  ( FIGS. 1 and 2 ) that mate with corresponding contacts in port  42  of accessory  10  or port  50  of computer  62  or other external equipment. Port  50  may be, for example, a USB port on a desktop or laptop computer (computer  62 ). Port  42  may be based on a connector such as connector  22  of  FIG. 1 . User input devices  54  may include touch screen displays, buttons, microphones, slider-type and rocker-type switches. Input-output ports in circuitry  52  such as input-output port  44  may be used to receive and transmit analog and digital signals with external equipment using input-output circuits such as circuitry  56  and circuitry  58 . 
     In a typical usage scenario, a user may initially plug device  12  into computer  62  to download media files from computer  62  to storage  48 . In this configuration, port  44  mates with port  50 . Switching circuitry in input-output circuitry  52  may be adjusted to connect digital communications circuitry  58  (e.g., USB communications circuitry) to the data terminals in contacts  20 , so that circuitry  58  may be used to receive digital data from computer  62 . Power lines may also be routed to the power contacts in contacts  20 . The received digital information may be stored in storage  48  for later use. 
     After downloading desired files, a user may connect device  12  to accessory  10 . In this configuration, port  44  mates with port  42 . The switching circuitry in input-output circuitry  52  may be readjusted to connect audio circuitry  56  to the data terminals (and ground terminal) in contacts  20  of port  44  in place of digital communications circuitry  58 . If it is desired to route power to accessory  10  from battery  18 , the positive power terminal in contacts  20  may be connected to the mating connector in port  42 . If this type of power supply voltage is not needed by accessory  10 , the positive power supply terminal in contacts  20  can be grounded or left floating. 
       FIG. 4A  is a bottom perspective view of an electronic device such as electronic device  12  of  FIG. 1 .  FIG. 4B  is a top perspective view of device  12  of  FIG. 4A . 
       FIG. 5  is an exploded perspective view showing components in an illustrative configuration for electronic device  12 . Buttons (e.g., buttons  34  in  FIG. 1 ) may be formed from switches such as dome switch  64 . Dome switch  64  may have a flexible dome-shaped (hemispherical) member  76  and a nub such as nub  78  (e.g., an epoxy nub that improves durability and accurate switch operation). The inner surface of member  76  may be metalized, so that when member  76  is compressed, dome switch contacts  66  and  68  are shorted together. Circuitry in components  32  may detect when switch  64  has been closed in this way and may take appropriate actions. Only one dome switch is shown in  FIG. 5 , but an electronic device such as a media player may, in general, have one or more buttons, two or more buttons, three or more buttons, four or more buttons, etc. 
     In the illustrative arrangement of  FIG. 5 , most or all of the exposed electrical traces on printed circuit board  16  are provided on the upper surface of board  16 . For example, contacts  20 , switch contacts  66  and  68 , and battery leads  28  are all formed from traces on the upper surface of board  16 . Upper surface traces are also used to form electrical connections with the contacts of components  32 . Battery  18  may be located above terminals  28  or, as shown in  FIG. 5 , battery  18  may be mounted below printed circuit board  16 . To ensure that signals can flow between terminals  30  of battery  18  and terminals  28 , terminals  28  may be formed from conformal traces having upper portions  70 , edge portions  72 , and rear surface portions  74 . Solder, welds, conductive adhesive, or other suitable electrical connections may be used to connect terminal portions  74  to terminals  30 . 
       FIG. 6  is a perspective view of device  12  showing how battery contacts  28  may be electrically connected to flexible (non-conformal) battery leads  30 ′. Leads  30 ′ may be formed as separate bent strips of metal that are connected at one end to pads  28  and at the other end to battery terminals  30  ( FIG. 1 ) or may be formed as part of the battery leads extending from the end of battery  18  (e.g., as part of terminals  30 ). 
     A cross-sectional side view of electronic device  12  showing how device  12  may have a thin housing such as a metal housing shell is shown in  FIG. 7 . As shown in  FIG. 7 , components  32  may be encapsulated by encapsulant  80 . Encapsulant  80  may be formed from one or more layers of dielectric such as epoxy or other adhesives, plastics (e.g., thermoplastic), glasses, ceramics, mixtures of dielectric and non-dielectric compounds, combinations of these materials, or other suitable materials. Encapsulant  80  may hermetically seal components  32  within device  12  and may help structurally affix components  32  to printed circuit board  16 . Contacts  20  may be formed on portion  21  of printed circuit board  16 , as described in connection with the example of  FIG. 1 . 
     Housing shell  84  may be formed from a metal such as stainless steel or aluminum, or may be formed from other materials (e.g., composites, plastics, etc.) An advantage of using metal to form shell  84  is that metal is relatively strong and may be provided with thin housing walls. Housings such as housing shell structure  84  of  FIG. 7  are optional and may be omitted if desired (e.g., to reduce weight). 
     As shown in  FIG. 7 , housing  84  may be configured to fit over encapsulant  80 . Housing  84  may be provided with an opening into which a pre-encapsulated structure may be inserted. Housing  84  may also be bent into shape over a pre-encapsulated structure. With another suitable arrangement, housing  84  may serve as a cavity for an injection molding process or other process in which encapsulant  80  is introduced into the cavity while printed circuit board  16  is held in place. With this type of approach, encapsulant may be introduced to expand to fill voids between printed circuit board  16  and components  32  and to fill gaps between components  32 , board  16 , and the inner surfaces of housing walls  84 . In a completed device, there may be few air gaps or no air gaps present in the interior of housing  84 . 
     Housing  84  may have portions such as portions  82  that serve as button member retention features. Portions  82  may help hold button member portions  34 ′ of buttons  34  in place above dome switch members  76 . 
     As shown in the illustrative arrangement of  FIG. 8 , buttons  34  may be formed by placing flexible button members  34 ″ over dome switches  64 . Adhesive or other fastening mechanisms may be used to hold flexible member  34 ″ to printed circuit board  16 . 
     Components  32  may be mounted to printed circuit board  16  using any suitable mounting arrangement. In the example of  FIG. 8 , component  32  has been mounted to printed circuit board  16  using a wire-bonding technique. As shown in  FIG. 8 , component  32  may have an upper surface on which contact pads  86  are formed. Wire  90  is used to electrically connect contact pads  86  to corresponding contact pads or printed circuit board  16  such as contact pad  94 . Wire bonding equipment may form a wire bond at each end of wire  90  (see, e.g., wire bonds  88  and  92  in the  FIG. 8  example). 
     Battery  18  may be electrically connected to board  16  using solder connections  96  or other suitable electrical connections. 
     Printed circuit board  16  may contain one or more layers. In a typical configuration, printed circuit board  16  contains multiple layers to allow internal traces to cross over each other without shorting to each other. The conductive traces in printed circuit board  16 , which are illustrated as traces  98  in  FIG. 8 , may be used to interconnect contacts  20 , components such as component  32 , buttons such as buttons  34 , battery  18 , and other circuits within device  12 . Encapsulant  80  may be used to encapsulate components  32  and, if desired, battery  18 . 
       FIG. 9  is a cross-sectional side view of an illustrative electronic device showing how flip-chip mourning techniques may be used to mount integrated circuits directly on a printed circuit board. As shown in  FIG. 9 , components such as individual integrated circuit die  32  may be flip-chip mounted to printed. circuit board  16  using solder balls  104 . Solder connections  96  may be used to attach battery  18  to the opposite side of printed circuit board  16  (as an example). Button  34  may be attached to printed circuit board  16  using solder  100  or other suitable connections. Encapsulant  80  may be used to encapsulate the flip-chip mounted integrated circuits  32 , battery  18  and at least the lower portion of button components such as button  34 . In the example of  FIG. 9 , button  34  has been implemented using a surface-mount button component or other stand-alone button unit that has been soldered to board  16 . This is merely illustrative. Buttons in device  12  such as button  34  of  FIG. 9  may be formed using any suitable technique (e.g., using flexible button coverings  34 ″ and dome switches  76  of  FIG. 8 , using button members  34 ′ and housing wall portions  82  of  FIG. 7 , etc.). 
     As shown in the arrangements of  FIGS. 8 and 9 , integrated circuit die may be mounted directly to printed circuit board  16  (e.g., using wire bonds, flip-chip mounting or other ball-grid array techniques, etc.). If desired, some or all of the electrical components in device  12  may be packaged before being mounted on board  16  and encapsulated by encapsulant  80 . This type of arrangement is shown in  FIG. 10 . 
     As shown in  FIG. 10 , battery  18  may be connected to printed circuit board  16  using solder connections  96 . Components  32  in the  FIG. 10  example are packaged integrated circuits. In each of these components, a separate integrated circuit die (die  105 ) is coupled to the interior contacts of the package by interior solder connections  106 . Package base  108  and package lid  110  form a package that hermetically seals die  105  from the environment. Encapsulant  112  may fully or partially surround die  105  in the cavity formed by the interior portion of the package to help protect die  105 . Traces in each package base  108  (shown as traces  116 ) may be used to connect solder connections  106  to solder connections  114 . Solder connections  114  may be used to connect packaged integrated circuits  32  to printed circuit board  16 . Battery  18  may be connected to printed circuit boards  16  using connections  96 . Buttons  34  may be connected to the same side or the opposite side of printed circuit board  16  using solder connections  100 . Other types of connections ma be used in forming electrical connections in device  12  if desired (e.g., friction-fit contacts such as pin-to-socket connections, spring contacts, welds, contacts formed from conductive adhesive, wire bonds, etc.). The use of solder connections is merely illustrative. 
     Once desired components have been mounted to printed circuit board  16 , encapsulant  80  may be used to cover and thereby encapsulate these components. Encapsulant  80  may, for example, cover both sides of board  16  and all associated components except the exposed button surfaces of buttons  34  and contacts  20 , thereby ensuring that the circuitry of integrated circuits  105  and other components will not be affected by changes in humidity, moisture intrusion events, etc. 
     Another illustrative device configuration is shown in  FIG. 11 . As shown in  FIG. 11 , device  12  may include a printed circuit board such as printed circuit hoard  16 . Packaged and unpackaged integrated circuits and other components may be attached to printed circuit board  16 . For example, packaged integrated circuits such as flip-chip mounted integrated circuit  105 A and wire-bond mounted integrated circuit  105 B may be mounted to printed circuit board  16 . Other components such as component  32 A and button  34  may be mounted to printed circuit board  16  on either the top or lower surface of board  16 . Battery  18  may be coupled to printed circuit hoard  16  using connections  96 . 
     In the  FIG. 11  example, contacts  20  have been provided as part of a connector assembly  118 . Connector assembly  118  may be, for example, an off-the-shelf connector such as a USB connector or a separately fabricated connector part that has a plastic housing, solderable leads to attach to printed circuit board  16 , and exposed contacts. Connector unit  118  may be mounted on printed circuit board  16  using solder connections  122  or other suitable electrical connections. Once mounted, internal conductors  120  may form electrical connections between each of contacts  20  and solder connections  122 . Encapsulant  80  and optional metal housing shell  84  may be formed over the mounted circuitry on board  16 . 
     Another way in which contacts  20  may be formed is shown in the cross-sectional side view of device  12  in  FIG. 12 . As shown in  FIG. 12 , device  12  may have contacts  20  that are formed at exposed ends  132  of leads  124 . Leads  124  may, for example, be formed from bent strips of metal such as copper, copper plated with gold, etc. Ends  126  of leads  124  may be connected to contact pads such as pad  130  on printed circuit board  16  using solder balls such as solder ball  128 . Integrated circuit die  105  may be mounted on printed circuit board  16  using solder balls  104 . Underfill  134  (e.g., epoxy or other suitable encapsulant material) may be used to help attach flip-chip mounted integrated circuit  105  directly to board  16  prior to encapsulation of integrated circuit die  105 , leads such as lead  124 , and other circuitry in device  12  by encapsulant  80 . As with all of the illustrative devices  12  that are depicted herein, an optional housing (e.g., a thin metal shell having a wall thickness of 0.5 mm or less, 0.3 mm or less, 0.1 mm or less, or other suitable dimensions) may be used to cover all or some of encapsulant  80 . 
     Components in device  12  may be covered with encapsulant using techniques such as spraying, pad printing, painting with a brush, dipping, dripping, injection molding, combinations of these techniques, or other suitable techniques. With one suitable arrangement, multiple injection molding shots of encapsulant may be incorporated in device  12 . 
     An illustrative arrangement of this type is shown in  FIG. 13 . As shown in  FIG. 13 , printed circuit board  16  may be populated with components  32  such as integrated circuit die that have been directly flip-chip mounted to the surface of board  16 , connectors, batteries, leads for forming connectors, buttons, etc. First encapsulation injection molding shot  80 A may be used to encapsulate some or all of these connectors. This first injection molding shot of material may, for example, be formed using an injection molding (insert molding) process implemented with an injection molding tool and a first mold. Epoxy or other encapsulant materials may also be used in forming encapsulant structure  80 A. 
     The first layer of encapsulant may be selected for compatibility with components  32 , cost, adhesion with board  16 , thermal properties, ease of fabrication, etc. Due to shrinkage, materials properties, or other factors, the outer surface of encapsulant  80 A may not be of sufficiently high quality to form the outermost surface of a finished device. Accordingly, one or more additional layers of material may be used in encapsulating device  12 . As shown in  FIG. 13 , for example, a second injection molding shot of thermoplastic such as shot  80 B or other materials (e.g., epoxy, etc.) may be formed on top of first injection molding shot  80 A. Optional housing shell  84  may be formed over second injection molding shot  80 B. 
     If desired, device  12  may contain multiple printed circuit boards. Each of the printed circuit boards may be electrically interconnected and may be encapsulated in a common encapsulation structure (encapsulant  80 ). 
     Some or all of printed circuit board  16  may also be omitted from device  12 . For example, components can be mounted directly to an integrated circuit die or other non-printed-circuit board substrate with little or no additional printed circuit board support. Encapsulant or other materials can then be included in device  12  to package and strengthen the substrate. 
     An arrangement of this type is shown in  FIG. 14 . As shown in  FIG. 14 , silicon integrated circuit die  105  may contain internal traces  136  (e.g., traces within a dielectric stack on the top layers oldie  105 ) and may contain circuitry such as circuits  138 . Circuits  138  may be bipolar transistor circuits, metal-oxide-semiconductor circuits (e.g., complementary metal-oxide-semiconductor integrated circuits), or other circuitry (e.g., circuitry of the type shown in  FIG. 3 ). Circuitry  138  may be interconnected with external components using contact pads. In the  FIG. 14  example, contact pad structures on the surface of integrated circuit die  105  may be used in forming contacts  20 . Contacts  20  may, if desired, be thickened using electroplating or other metal deposition techniques. Contact pads may also be used in forming, connections to components such as dome switch  64  in buttons such as button  34 . In particular, ring-shaped contact pad  68  may be formed in a circle around dot-shaped contact pad  66 . Metallized dome switch member  76  may be mounted above pads  66  and  68  to form a switch for button  34 . Button  34  may also have a button member such as member  34 ″ that form an outer surface for the button. 
     If desired, other components may be mounted to integrated circuit die  105  of  FIG. 14 . For example, battery  18 , additional buttons, contact leads, packaged and unpackaged integrated circuits, discrete components such as capacitors, inductors, and resistors, and other circuitry may be mounted to the surface of integrated circuit chip  105  using contact pads, solder connections, spring-loaded connections, or other suitable electrical connections. Once desired components have been electrically connected to integrated circuit die  105 , appropriate portions of these components may be encapsulated with one or more layers of encapsulant  80 . When encapsulant  80  has cured and hardened sufficiently, the strength provided by the hardened encapsulant can add structural strength to integrated circuit die  105  that makes die  105  sufficiently strong to use as device  12 . 
     Illustrative steps involved in fabricating electronic device  12  are shown in  FIG. 15 . 
     At step  140 , one or more integrated circuit die such as die  105  may be fabricated using semiconductor processing techniques. During fabrication, contact pads may be formed on the surface of the integrated circuit die. 
     At step  142 , the integrated circuit die may, if desired, be mounted in a package. The package may have ceramic or plastic walls and may include encapsulant, solder balls, wire bonds, etc. 
     If desired, the packaging operations of step  142  may be omitted (e.g., when it is desired to form device  12  from one or more unpackaged integrated circuit die). 
     At step  144 , electrical components such as buttons, leads, discrete components, and the integrated circuits (packaged or unpackaged) may be mounted to a mounting structure. For example, the integrated circuits and other components may be mounted to a printed circuit board substrate or other substrate that contains metal interconnects. Examples of substrates that may be used for mounting the integrated circuits include plastic mounting structures, rigid printed circuit boards, flex circuits, rigid flex, glass, ceramic, etc. In configurations of the type shown in  FIG. 14  in which no printed circuit board is used, components may be attached directly to an integrated circuit die. 
     After suitable electrical connections have been formed between the integrated circuits and other components, these structures may be fully or partially encapsulated using encapsulant  80 . Encapsulant  80  may be formed on the surface of device  12  using dipping, spraying, pad printing, dripping, injection molding, or other suitable techniques. If desired, multiple layers of material may be used to encapsulate components. For example, a first injection molding shot of thermoplastic and/or an epoxy layer may be used as an interior coating, for components. A second injection molding shot of thermoplastic or other material may then be used to form a second or outer encapsulating layer. If desired, additional layer of encapsulant may be formed. Injection molding tools and other fabrication tools may be used in encapsulating the components of device  12 . During encapsulation operations, contacts  20  and other such structures are preferably left uncoated with encapsulant. Leaving contacts  20  exposed to the exterior of device  12  allows contacts  20  to be connected to corresponding contacts in a mating device during normal operation. 
     At step  148  (or as part of step  146 ), device  12  may be provided with an optional housing such as housing  84  of  FIG. 1 . Housing  84  may have interior dimensions that exactly or nearly match the exterior dimensions of encapsulant  80 . If desired, the encapsulation operations of step  146  may be performed by injecting encapsulant into housing  84  to ensure that interior voids are filled. Housing  84  may also be formed by crimping or otherwise attaching metal pieces to the exterior of the structure formed by cured encapsulant  80 . 
     Because techniques such as these may be used to form structurally sound encapsulation structures, it is not necessary to mount the components of a device in conventional housing structures, thereby potentially saving space and improving device aesthetics. Music players and other electronic devices may be formed using techniques of the type described in connection with  FIG. 15 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing, from the scope and spirit of the invention.

Metadata:
Filing Date: 20180327
Publication Date: 20190514
Grant Date: 20190514
Priority Date: 20091201
Inventors: PREST, CHRISTOPHER D.
DI LEO, CLAUDIO
Assignee: APPLE INC
CPC Classifications: [{"code": "Y10T29/49146", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73204", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/32225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/19107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48091", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/09701", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/00014", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/1305", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K7/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L2924/19041", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/3107", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/3107", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T29/49146", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/31", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L2924/09701", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/32225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73204", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/3107", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/19107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73204", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/32225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48091", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/19041", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48091", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/09701", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/1305", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49146", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/1305", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K7/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/3107", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/19107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73204", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/32225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48091", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/09701", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/19041", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 43798427