PATENT DOCUMENT

Publication Number: US-9179537-B2
Application Number: US-201213714186-A
Country: US
Kind Code: B2

Title: Methods for forming metallized dielectric structures

Abstract:
An electronic device may be provided with metal coated dielectric structures that serve as electromagnetic interference shielding, antenna structures, or other metal structures. The metal coated dielectric structures may be formed form a sheet of polymer. Metal may be deposited on the sheet of polymer using a deposition tool and patterned following deposition or may be patterned during deposition. A dielectric sheet having patterned metal may be shaped into a desired shape using molding equipment or other equipment that applies heat and pressure to the dielectric sheet and patterned metal. Metal on a dielectric sheet may also be patterned after the dielectric sheet is formed into a desired shape. Metal may be formed on opposing sides of the dielectric sheet.

Claims:
What is claimed is: 
     
       1. A method of forming an electromagnetic interference shield to shield a component that has a shape, comprising:
 coating a polymer sheet with metal; and 
 after coating the polymer sheet with metal, covering the component with the polymer sheet coated with the metal so that the polymer sheet conforms to the shape of the component. 
 
     
     
       2. The method defined in  claim 1  wherein the polymer sheet comprises a thermoplastic polymer. 
     
     
       3. The method defined in  claim 1  wherein covering the component comprises heating the polymer sheet. 
     
     
       4. The method defined in  claim 1  wherein the component comprises an integrated circuit and wherein covering the component comprises covering the integrated circuit with the polymer sheet coated with the metal. 
     
     
       5. The method defined in  claim 1  further comprising:
 patterning antenna structures on the polymer sheet. 
 
     
     
       6. The method defined in  claim 1  wherein coating the polymer sheet with metal comprises:
 laminating a metal layer to the polymer sheet with a lamination tool; and 
 after laminating the metal layer to the polymer sheet with the lamination tool and before covering the component with the polymer sheet coated with the metal, patterning the laminated metal layer with a patterning tool. 
 
     
     
       7. The method defined in  claim 1  wherein coating the polymer sheet with metal comprises depositing patterned metal on the polymer sheet. 
     
     
       8. The method defined in  claim 1  wherein coating the polymer sheet with metal comprises electroplating the metal. 
     
     
       9. The method defined in  claim 1  wherein the polymer sheet has first and second opposing surfaces and wherein coating the polymer sheet with metal comprises forming metal structures on the first and second opposing surfaces. 
     
     
       10. The method defined in  claim 1 , wherein coating the polymer sheet with metal comprises coating the polymer sheet such that the metal is in direct contact with the polymer sheet. 
     
     
       11. A method of forming antenna structures, comprising:
 forming patterned metal structures on a dielectric layer; and 
 after forming the patterned metal structures on the dielectric layer, molding the dielectric layer with the patterned metal traces into a shape having at least one recess. 
 
     
     
       12. The method defined in  claim 11  wherein forming the patterned metal structures on the dielectric layer comprises:
 coating the dielectric layer with metal; and 
 after coating the dielectric layer with metal, patterning the metal with a patterning tool. 
 
     
     
       13. The method defined in  claim 11  wherein molding the dielectric layer comprises heating the dielectric layer with a molding tool. 
     
     
       14. The method defined in  claim 11  wherein forming the patterned metal structures on the dielectric layer comprises forming the patterned metal structures on a thermoplastic polymer. 
     
     
       15. The method defined in  claim 11  wherein the dielectric layer comprises a sheet of polymer having opposing first and second surfaces and wherein forming the patterned metal structures comprises forming metal structures on both the first and second surfaces. 
     
     
       16. A method of forming antenna structures, comprising:
 forming patterned metal structures on a dielectric layer; and 
 molding the dielectric layer with the patterned metal traces into a shape having at least one recess, wherein the dielectric layer comprises a sheet of polymer having opposing first and second surfaces, wherein forming the patterned metal structures comprises forming metal structures on both the first and second surfaces, and wherein forming the metal structures on the first and second surfaces comprises forming antenna resonating element structures on the first surface and forming electromagnetic signal shielding structures on the second surface. 
 
     
     
       17. The method defined in  claim 11 , wherein forming patterned metal structures on a dielectric layer comprises forming the patterned metal structures in direct contact with the dielectric layer.

Description:
BACKGROUND 
     This relates to electronic devices and, more particularly, to dielectric substrates with metal coatings for forming components in electronic devices. 
     Electronic devices such as cellular telephones and other portable devices are often provided with radio-frequency circuitry and other components. Such circuitry often requires electromagnetic interference shielding or is coupled to antenna structures. In an antenna, patterned metal traces may be formed on a dielectric substrate such as a polymer substrate. Metal shielding cans may be used to enclose and electromagnetically shield radio-frequency integrated circuits. 
     It can be challenging to form metal structures such as shielding cans and antennas for use in electronic devices. In some situations, the amount of space within an electronic device is limited, making it difficult or impossible to use conventionally designed structures. 
     It would therefore be desirable to be able to provide improved metal structures for an electronic device such as improved shielding structures and antenna structures. 
     SUMMARY 
     An electronic device may be provided with metal coated dielectric structures that serve as electromagnetic interference shielding, antenna structures, or other metal structures. 
     The metal coated dielectric structures may be formed from a polymer such as a polyimide, polyethylene terephthalate (PET), liquid crystal polymer, or other dielectric materials. The dielectric may be provided as a thin layer of material such as a thin polymer sheet. 
     Metal may be deposited on the sheet of polymer using a deposition tool and patterned following deposition. Metal may also be patterned during deposition using a shadow mask, pad printing equipment, screen printing equipment, or other metal deposition tools. A dielectric sheet having patterned metal may be shaped into a desired shape using molding equipment or other equipment that applies heat and pressure to the dielectric sheet and patterned metal. Metal on a dielectric sheet may also be patterned after the dielectric sheet is formed into a desired shape. 
     Metal coated plastic parts may be lighter than comparable sheet metal parts, thereby allowing weight in an electronic device to be minimized. The use of additional insulating layers of the type that are sometimes used on the underside of sheet metal shielding cans to ensure electrical isolation between shielded components and the shielding cans may also be reduced or eliminated by forming shielding structures from metal coated plastic parts. 
     If desired, metal may be formed on multiple sides of a polymer sheet. The metal may be used in forming shielding structures, antenna structures, a combination of shielding structures and antenna structures, or other patterned metal structures. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an illustrative electronic device in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of illustrative antenna circuitry and radio-frequency transceiver circuitry in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram showing how a metal structure on a dielectric substrate may be formed by attaching metal to a dielectric structure and performing shaping operations on the dielectric and metal structure in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram showing how a metal structure on a dielectric substrate may be formed by molding metal and dielectric material in accordance with an embodiment of the present invention. 
         FIG. 5  is a diagram showing how a metal structure on a dielectric substrate may be formed by patterning metal onto a dielectric substrate and shaping the metal and dielectric in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of a system with components such as integrated circuits mounted on a printed circuit board that has been surrounded by a layer of dielectric coated with metal in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of the structures of  FIG. 6  following the formation of an electromagnetic shield using the layer of dielectric coated with metal in accordance with an embodiment of the present invention. 
         FIG. 8  is a diagram of a system in which a surface modification tool such as a light source is being used to activate a portion of a dielectric surface so that the activated portion of the dielectric surface may be selectively coated with metal in accordance with an embodiment of the present invention. 
         FIG. 9  is a diagram of a system in which a sheet of polymer or other dielectric has been formed with metal coatings on opposing first and second surfaces and has been mounted to a substrate using conductive structures in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an illustrative polymer sheet coated on one surface with patterned metal to form structures such as antenna structures and coated on an opposing surface with metal to form structures such as shielding structures in accordance with an embodiment of the present invention. 
         FIG. 11  is a perspective view of an illustrative shielding can mounted to a printed circuit substrate in a configuration in which the shielding can has peripheral openings to facilitate the formation of electrical connections to contacts on the printed circuit substrate in connection with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of the shielding can of  FIG. 11  showing how solder or other conductive material may protrude through the peripheral openings around the edge of the shielding can to help electrically connect the shielding can to traces on the printed circuit board in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Dielectrics covered with metal may be used to form electromagnetic interference shielding structures, antenna structures, and other structures in an electronic device. An illustrative electronic device of the type that may be provided with structures such as these is shown in  FIG. 1 . Device  10  of  FIG. 1  may be a handheld device such as a cellular telephone or media player, a tablet computer, a notebook computer, other portable computing equipment, a wearable or miniature device such as a wristwatch or pendant device, a television, a computer monitor, or other electronic equipment. 
     As shown in  FIG. 1 , electronic device  10  may include a display such as display  14 . Display  14  may be a touch screen that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components or may be a display that is not touch-sensitive. Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. Configurations in which display  14  includes display layers that form liquid crystal display (LCD) pixels may sometimes be described herein as an example. This is, however, merely illustrative. Display  14  may include display pixels formed using any suitable type of display technology. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button  16  and an opening such as opening  18  may be used to form a speaker port. Device configurations without openings in display  14  may also be used for device  10 . 
     Device  10  may have a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. 
     Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
       FIG. 2  is a diagram of illustrative circuitry of the type that may be included in electronic devices such as electronic device  10  of  FIG. 1 . As shown in  FIG. 2 , device  10  may include antenna structures  20 . Antenna structures  20  may include antennas such as inverted-F antennas, planar inverted-F antennas, loop antennas, patch antennas, slot antennas, dipole antennas, monopole antennas, other suitable antennas, or antennas formed from multiple antenna structures of these types. 
     Antenna structures  20  may be coupled to radio-frequency transceiver circuitry  28  by one or more transmission lines such as transmission line  26 . Transmission line  26  may be formed from a coaxial cable, from microstrip or stripline transmission line traces on a printed circuit board or other dielectric substrates, or from other transmission line structures. As shown in  FIG. 2 , transmission line  24  may include a positive conductor such as conductor  22  and a ground conductor such as conductor  24 . Paths  22  and  24  may be formed from metal traces, wires, strips of metal, portions of conductive housing structures in device  10  such as housing  12 , or other conductive structures in device  10 . 
     Radio-frequency transceiver circuitry  28  may include cellular telephone transceiver circuitry, circuitry for wireless local area network transceivers (e.g., IEEE 802.11 circuitry), Bluetooth® circuitry, satellite navigation system circuitry, or other radio-frequency transmitter and receiver circuitry. 
     Device  10  may also include other circuitry  30  such as processors, display drivers, application-specific integrated circuits, memory, and other circuitry. To prevent interference between circuits that generate radio-frequency signals and/or that are sensitive to interference from incoming radio-frequency signals, circuitry such as radio-frequency transceiver circuitry  28  (e.g., one or more transceiver integrated circuits) and/or other circuitry  30  may be provided with electromagnetic interference shielding structures such as electromagnetic interference shielding structures  32 . 
     Structures such as antenna structures  20 , shielding structures  32 , and other metal structures in device  10  may be formed from dielectrics coated with metal. The dielectric material in these structures may serve as a supporting structure. Polyimide, polyethylene terephthalate (PET), liquid crystal polymers, or other polymers may be used to form dielectric supporting structures. Polyimide, polyethylene terephthalate, liquid crystal polymers, and other polymers may exhibit low loss tangents (i.e., small amounts of radio-frequency signal loss) and may be mechanically robust (e.g., these polymers may withstand damage at high temperatures). Polyimide, polyethylene terephthalate, liquid crystal polymers, and other polymers may also be readily workable (e.g., using heated molds) and may be formed into thin layers (e.g., layers of 0.2 mm or less in thickness, layers of 0.1 mm or less in thickness, layers of 0.02 to 0.2 mm in thickness, etc.). 
     Metal for coating the dielectric in structures  20 , structures  32 , or other metal coated dielectric structures in device  10  may include gold, copper, stainless steel, nickel, brass, other metals, or combinations of these metals. Patterned metals may be used to form antenna resonating element traces or metal for shielding cans. Metal may also be deposited as a blanket coating on a dielectric without extensive patterning. 
       FIG. 3  shows how metal structures such as shielding structures, antennas, or other metal structures may be formed for device  10 . 
     As shown in  FIG. 3 , processing equipment such as lamination tool  38  may receive dielectric  34  and metal  36 . Dielectric  34  may be a polymer or other suitable material. As an example, dielectric  34  may be a thermoplastic polymer that is characterized by a low loss tangent making dielectric  34  suitable for use in forming an antenna substrate. Dielectric  34  may also be formed from other polymeric materials. Examples of polymers that may be used in forming dielectric  34  include liquid crystal polymer, polyimide, and polyethylene terephthalate. Other types of polymer, glass, ceramic, other dielectrics, or combinations of these materials may be used in forming dielectric  34  if desired. 
     Dielectric  34  may have the shape of a block (e.g., a rectangular prism), a shaped non-rectangular solid, or a thin sheet (e.g., a sheet with a thickness of 0.2 mm or less, a substrate with a thickness of 0.1 mm or less, or a sheet with a thickness of 0.02 to 0.2 mm, as examples). Illustrative configurations for dielectric  34  in which dielectric  34  is based on a thin sheet of material are sometimes described herein as an example. Other types of shapes for dielectric  34  may be used if desired. 
     Metal  36  may be include copper, gold, nickel, stainless steel, brass, or other metals. Metal  36  may be formed from a thin metal sheet (e.g., metal foil with a thickness of 0.1 mm or less, 0.03 mm or less, 0.1 to 0.005 mm, etc.), may be formed from metal wire, may be formed from strips of metal or metal of other shapes, may be deposited as a coating (e.g., to form metal traces on a substrate), or may have other shapes. Metal  36  may include one type of metal, multiple types of metal (e.g., multiple metal layers), may be formed from a metal alloy, or may be formed from other metal structures. 
     Using a system arrangement of the type shown in  FIG. 3 , lamination tool  38  may laminate a sheet of metal such as metal sheet  36  onto a surface of dielectric  34  (e.g., the upper surface of a sheet of dielectric  34  and/or one or more other surfaces of dielectric  34 ). Resulting metal coated structures  40  may have a thickness T of 0.2 mm or less, 0.1 mm or less, 0.02 to 0.2 mm, or more than 0.02 mm). Heat, pressure, and/or adhesive and other attachment mechanisms may be used in attaching metal layer  36  to substrate layer  34 . 
     Following use of lamination tool  38  to form dielectric structures coated with an unpatterned metal coating, patterning tool  42  may be used in forming metal structures  40  with patterned metal  36  (e.g., metal with openings such as openings  44 ). Patterning tool  42  may include laser etching equipment, dry or wet chemical etching equipment, machining equipment, or other equipment for patterning metal  36  on dielectric layer  34 . 
     Molding tool  46  may be used to shape structures  40  into a desired shape following metal patterning. As shown in  FIG. 3 , for example, molding tool  46  may be used to heat and press structures  40  into a shape with recesses such as recess  48  (and a corresponding raised portion on the opposing side of structures  40 ). Structures with curved surfaces and complex features may be formed. The shape into which structures  40  are formed may be used to form an electromagnetic interference shield, antenna structures, or other metal coated dielectric structures for device  10 . 
     In the illustrative configuration of  FIG. 4 , dielectric  34  and metal  36  may be shaped together to form shaped metal coated dielectric structures  40  (e.g., structures  40  that include raised features and depressions such as recess  48 ). Following shaping of structures  40 , patterning tool  42  may be used to pattern metal coating layer  36  (e.g., to form openings  44 ). 
     If desired, metal  36  may be deposited and patterned onto dielectric  36  using patterned layer deposition equipment  50 , as shown in  FIG. 5 . Equipment  50  may pattern metal  36  while metal  36  is being deposited on layer  34 . For example, metal  50  may include a shadow mask and physical vapor deposition equipment that deposits metal  50  onto dielectric layer  34  through the shadow mask or may include equipment for laminating pattered metal foil onto dielectric layer  34 . As another example, metal  50  may be deposited using an ink-jet printer, by spraying or spinning metal paint onto layer  34 , or by patterning metal paint or other conductive material onto layer  34  using pad printing, screen printing, dripping, or other deposition and patterning techniques. 
     Following the formation of patterned metal  36  on dielectric  34  to form metal coated structures  40 , equipment such as molding tool  46  may be used to shape metal coated dielectric structures  40  into a desired shape (e.g., a shape having raised portions and depressed portions such as recess  48 ). Molding equipment  46  may include a metal die having a shape that is matched to a desired end shape for structures  40  and heating equipment that heats the metal die. The heated die may, through application of heat and pressure, cause dielectric  34  (and thin metal coating  36 ) to assume a desired end shape, such as the shape of  FIG. 5  that includes recess  48 . 
       FIG. 6  shows how components such as integrated circuits  54  in device  10  may be mounted on a substrate such as printed circuit  56 . Printed circuit  56  may be a rigid printed circuit board (e.g., a printed circuit board formed from a substrate material such as fiberglass-filled epoxy) or may be a flexible printed circuit (e.g., a printed circuit formed from patterned metal traces on a flexible substrate such as a layer of polyimide or a flexible sheet of other polymers). Integrated circuits  54  may include radio-frequency transceiver circuitry such as circuitry  28  of  FIG. 2  and other circuitry  30 . 
     Metal coated dielectric sheet  40  may be formed from a layer of metal such as metal  36  on a flexible dielectric sheet such as sheet  34 . Metal  36  may be a layer of copper or other metal. Dielectric sheet  34  may be a sheet of liquid crystal polymer or other flexible polymer material (as examples). Metal coated dielectric sheet  40  may be wrapped around circuitry such as integrated circuits  54  on printed circuit  56  as shown in  FIG. 6 . Sheet  40  may have ends that overlap or that join along a seam or may be formed from a tube of material that slides over integrated circuits  54  and printed circuit  56 . Metallized structures  40  may be used in a shape of the type shown in  FIG. 6  that surrounds circuitry such as circuits  54  and printed circuit  56  to serve as an electromagnetic interference shield, antenna structures, or other metallized dielectric structures. Structures  40  may also be shaped further before use in device  10 , if desired. 
     As shown in  FIG. 7 , for example, metal coated dielectric sheet  40  may be shaped to conform to the surfaces of components such as integrated circuits  54  and printed circuit  56  or other internal device structures. Metal coated dielectric sheet  40  may, for example, be caused to shrink and otherwise conform to circuits  54  and printed circuit  56  by applying heat in an oven or other heat application equipment (as with heat-shrink plastic), using a vacuum (e.g., in a vacuum lamination tool), using pressure (e.g., in a mold or press), etc. By conforming metal coated dielectric sheet  40  to the outer surfaces of integrated circuits  54  and printed circuit  56  (or other device structures), metal coated dielectric sheet  40  may serve as an electromagnetic interference shield (i.e., a compact potentially thin-walled shielding can). If desired, metal  36  of  FIG. 7  may be patterned to form antenna traces for antenna structures such as antenna structures  20  of  FIG. 2  or other metal structures in device  10 . 
     Metal  36  may be patterned using techniques that selectively activate portions of the surface of dielectric  34  for subsequent metal electroplating. As shown in  FIG. 8 , for example, a laser or other light source  60  may produce light beam  62 . Light beam  62  (or mechanical roughening equipment) may be used to create a region such as region  64  on the surface of dielectric  34  that is activated relative to the remaining (unactivated) portions of dielectric  34 . Plating tool  66  or other metal deposition equipment may be used to deposit metal  36  on the surface of dielectric  34  (e.g., using electrochemical deposition techniques such as plating techniques for electroplating metals such as copper, gold, nickel, etc. or using other electroplating techniques). During plating operations with tool  66 , metal  36  will only be deposited in the patterned regions  64  that were activated using surface activation equipment such as light source  60 , thereby creating patterned metal  36  in metal-coated dielectric structures  40 . Molding techniques or other shaping techniques may then be used to form radio-frequency shielding structures, antenna structures, or other metal coated dielectric structures for device  10 . If desired, patterned metal deposition techniques of the type shown in  FIG. 8  may be formed after dielectric  34  has been shaped to a desired shape (e.g., after molding dielectric  34  into a shape with protrusions and depressions, after conforming dielectric  34  to the surface of integrated circuits or other components, etc.). 
     If desired, dielectric  34  may be coated with metal on opposing surfaces.  FIG. 9  is a diagram of a system of the type that may be used in forming metal-coated dielectric structures that include metal coatings on both sides of a sheet of dielectric. 
     As shown in  FIG. 9 , processing equipment such as lamination, patterning and molding equipment  70  may receive dielectric  34  and metal  36 . Dielectric  34  may be a polymer or other suitable material. As an example, dielectric  34  may be a thermoplastic polymer that is characterized by a low loss tangent. Dielectric  34  may have the shape of a block (e.g., a rectangular prism), a shaped non-rectangular solid, or a thin sheet (e.g., a sheet with a thickness of 0.2 mm or less, a substrate with a thickness of 0.1 mm or less, or a sheet with a thickness of 0.02 to 0.2 mm, as examples). 
     Metal  36  may include one or more layers of metal such as layers  36 A and  36 B. Metal  36  may be copper, gold, nickel, stainless steel, brass, or other metals. Metal  36  may be formed from one or more thin metal sheets (e.g., metal foil with a thickness of 0.1 mm or less, 0.03 mm or less, 0.1 to 0.005 mm, etc.), may be formed from metal wire, may be formed from strips of metal or metal of other shapes, may be deposited as a coating (e.g., to form metal traces on a substrate), or may have other shapes. Metal  36  may include one type of metal, multiple types of metal (e.g., multiple metal layers), may be formed from a metal alloy, or may be formed from other metal structures. 
     Lamination equipment in equipment  70  may be used to laminate metal  36  to dielectric  34  before or after patterning using patterning equipment in equipment  70 . As an example, metal sheet  36 A may be laminated to an upper surface of dielectric  34  and metal sheet  36 B may be laminated to an opposing lower surface of dielectric  34 . Patterning equipment may then be used to pattern the layers of metal  36  that have been formed on the surfaces of dielectric  34 . As another example, patterning equipment (e.g., stamping equipment, etc.) may be used to pattern metal  36  before attaching the patterned metal to dielectric  34 . Metal  36  may be attached to dielectric  34  using heat and/or adhesive. Molding equipment in equipment  70  may be used to mold dielectric  34  and metal  36  after attachment of patterned metal  36  to dielectric  34  or before patterning metal  36  on the surfaces of dielectric  34 . Metal  36  may also be formed on the surface of dielectric  34  as part of a molding process (if desired). 
     Following formation of metal-coated dielectric structures  40  of  FIG. 9 , metal-coated dielectric structures  40  may have an upper metal coated surface such as metal layer  36 A and may have a lower metal coated surface such as metal layer  36 B. Structures  36 A and  36 B may form a metal electromagnetic signal shielding structure, antenna structures, contact pads, etc. 
     Metal-coated dielectric structures  40  may be mounted on a substrate such as substrate  78 . Substrate  78  may be a piece of dielectric such as a block of plastic or may be a sheet of dielectric such as a rigid or flexible printed circuit substrate. 
     Soldering tool  72  may be used to solder metal-coated dielectric structures  40  to substrate  98 . As shown on the lower left of  FIG. 9 , solder  82  may be used to attach lower surface metal coating  36 B on metal-coated dielectric structures  40  to substrate  78 . Upper surface metal coating  36 A may be an integral part of lower surface metal coating  36 B (i.e., metal coating  36 A may extend continuously around the edges of dielectric  34 ) or may be attached to dielectric  34  as a separate layer. With one illustrative embodiment, metal  36 A and/or  36 B is used in forming an electromagnetic signal shield. 
     Substrate  78  may have contact pads such as contact pads  80 . Pads  80  may be electrically connected to patterned conductive material on substrate  78  such as patterned interconnect lines, ground plane structures, and other conductive structures. 
     Dielectric  34  may have a shape with a cavity that receives one or more components such as component  84 . Component  84  may be, for example, an integrated circuit. Component  84  may be mounted on substrate  78  using solder  82  and contact pads  80 . Metal-coated dielectric structures  40  may serve as a shield for components such as component  84 . 
     As shown on the lower center of  FIG. 9 , conductive adhesive  86  may be used to attach lower surface metal coating  36 B on metal-coated dielectric structures  40  to substrate  78 . Conductive adhesive  86  may be a liquid conductive adhesive or a conductive pressure sensitive adhesive (as examples). Tool  74  may be used in mounting structures to substrate  78  using adhesive  86 . 
     Substrate  78  may have contact pads such as contact pads  80  that are electrically connected to interconnects and other conductive structures in substrate  78 . Components such as component  84  may be mounted on one or more contact pads  80  using solder, conductive adhesive  86  (as shown in  FIG. 9 ), or other conductive material. Dielectric  34  may be shaped to form a cavity that accommodates components such as component  84 . 
     If desired, conductive tape may be used in mounting metal-coated dielectric structures  40  to substrate  78 . Tape  90  may be applied using taping equipment  76 . As shown in the lower right-hand corner of  FIG. 9 , tape  90  may include a conductive layer such a conductive backing layer  92  and an adhesive layer such as adhesive  94 . Adhesive  94  may be a conductive adhesive. Backing layer  92  may be formed from metal foil or a conductive fabric (e.g., a fabric formed from metal fibers or metal coated plastic fibers). 
     Metal-coated dielectric structures  40  may have a cavity that accommodates one or more components such as component  96 . Component  96  may be mounted to pads such as pad  80  on substrate  78  using conductive material  94  (e.g., conductive adhesive, solder, etc.). Metal-coated dielectric structures  40  may have metal such as upper metal layer  36 A on the top surface of dielectric layer  34  and lower metal layer  36 B on the opposing lower surface of dielectric layer  34 . Layers  36 A and  36 B may be electrically isolated from each other or may be shorted to each other. Using conductive tape  90 , metal on dielectric  34  (e.g., metal layer  36 A and/or  36 B) may be electrically connected to pads  80 . Tape  90  may also help hold metal-coated dielectric structures  40  in place on substrate  78 . 
       FIG. 10  is a cross-sectional side view of metal-coated dielectric structures in an illustrative configuration in which upper metal layer  36 A has been patterned to form an antenna. In particular, metal layer  36 A on the outer surface of dielectric  34  has been patterned to form antenna structures  36 A- 1  and  36 A- 2 . 
     Structures  36 A- 1  and  36 A- 2  may include antenna ground structures, parasitic antenna structures, antenna resonating element structures based on inverted-F antennas, patch antennas, planar inverted-F antennas, loop antennas, and other types of antennas, and other antenna structures. As an example, structures  36 A- 1  may form an antenna resonating element that is coupled to transmission line path  22  of transmission line  26  ( FIG. 2 ) and structures  36 A- 2  may form an antenna ground that is coupled to transmission line path  24  of transmission line  26  ( FIG. 2 ). 
     Dielectric  34  may serve to isolate antenna structures  36 A from metal layer  36 B on the lower surface of dielectric  34 . Metal layer  36 B may form a shielding layer or other conductive structures and may be electrically connected to contact pads on substrate  78  using conductive material  100  such as solder or conductive adhesive. 
     The shape of dielectric  34  may be configured to form a cavity that accommodates one or more components such as component  102 . Conductive material  100  such as solder or conductive adhesive may be used to mount components such as component  102  to contact pads on substrate  78 . 
     If desired, dielectric  34  of  FIGS. 9 and 10  may conform to the shape of the components that are mounted under dielectric  34  (e.g., by applying heat to allow dielectric  34  to deform). 
     A perspective view of an illustrative shielding can formed from metal-coated dielectric structures mounted to a substrate is shown in  FIG. 11 . As shown in  FIG. 11 , metal-coated dielectric structures  40  may have a shape that serves to cover and shield one or more electrical components mounted on substrate  78 . Metal may be formed on the upper (outer) surface of the dielectric in structures  40 , on the lower (inner) surface of the dielectric in structures  40 , or on both the upper and lower surface of the dielectric in structures  40 . Substrate  78  may be a piece of dielectric such as a block of plastic or may be a sheet of dielectric such as a rigid or flexible printed circuit substrate. Peripheral lip portion  200  of metal-coated dielectric structures  40  may run around the edge of structures  40  and may have peripheral openings such as openings  202 . Solder or other conductive material may be placed in openings  202  to mount metal-coated dielectric structures  40  to printed circuit board. 
     A cross-sectional side view of metal-coated dielectric structures  40  of  FIG. 11  is shown in  FIG. 12 . The cross-sectional side view of  FIG. 12  is taken along line  204  and viewed in direction  206  of  FIG. 11 . As shown in  FIG. 12 , metal-coated dielectric structures may have a shape that defines a cavity such as cavity  208 . Electrical components  102  may be mounted on substrate  78  within cavity  208  (i.e., metal-coated dielectric structures  40  may serve as a radio-frequency shield). 
     Solder  210  may be placed in openings  202  to mount metal-coated dielectric structures  40  to metal traces in substrate  78  such as metal contact pads  216 . Pads  216  may be, for example, ground structures that help ground metal-coated dielectric structures  40 . Metal-coated dielectric structures  40  may have a dielectric layer such as dielectric layer  34  that is coated with an upper metal coating layer such as upper layer  212 , a lower metal coating layer such as coating layer  214 , or that is coated with both upper coating layer  212  and lower metal coating layer  214 . Solder  210  may electrically connect (short) layers such as layer  212  and/or  214  to metal traces  216  (e.g., solder  210  may short the metal of metal-coated dielectric structures  40  to ground so that structures  40  may serve as a radio-frequency shield for components  102 ). 
     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. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20121213
Publication Date: 20151103
Grant Date: 20151103
Priority Date: 20121213
Inventors: RAPPOPORT BENJAMIN M.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K1/0243", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0216", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/0243", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T156/1028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0216", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T29/49016", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 50929635