PATENT DOCUMENT

Publication Number: US-10225964-B2
Application Number: US-201615250066-A
Country: US
Kind Code: B2

Title: Component shielding structures with magnetic shielding

Abstract:
Electrical components may be shielded using a shielding can or other shielding structure that covers the electrical components. The electrical components and the shielding structure may be mounted on a substrate such as a printed circuit board using solder or other conductive material. The shielding structure may have one or more shielding layers. The shielding layers may include high conductivity material for providing shielding for radio-frequency electromagnetic interference and magnetic material for blocking magnetic flux. Shielding structures may be formed from materials such as ferritic stainless steel, coatings that enhance solderability, corrosion resistance, and conductivity, magnetic materials printed or otherwise formed on metal layers, and other shielding structures.

Claims:
What is claimed is: 
     
       1. Apparatus, comprising:
 a substrate; 
 at least one electrical component mounted on the substrate; and 
 a shielding can attached to the substrate that covers and shields the electrical component, wherein the shielding can includes a plurality of layers of material including a layer of magnetic shielding material, the plurality of layers of material include first and second cladding layers on opposing sides of the layer of magnetic shielding material, the first and second cladding layers are larger than the layer of magnetic shielding material, edge portions of the first and second cladding layers are joined together without any intervening portions of the magnetic shielding material, and the edge portions of the first and second cladding layers are mounted on the substrate. 
 
     
     
       2. The apparatus defined in  claim 1  wherein the layer of magnetic shielding material has a relative permeability of at least 500. 
     
     
       3. The apparatus defined in  claim 1  wherein the layer of magnetic shielding material has a relative permeability of at least 1000. 
     
     
       4. The apparatus defined in  claim 1  wherein at least one of the first and second cladding layers is a radio-frequency electromagnetic interference shielding layer. 
     
     
       5. The apparatus defined in  claim 4  wherein the radio-frequency electromagnetic interference shielding layer is a metal layer. 
     
     
       6. The apparatus defined in  claim 5  wherein the metal layer has a resistivity of less than 3×10 8  ohm-m. 
     
     
       7. The apparatus defined in  claim 6  wherein the layer of magnetic shielding material is a printed layer of magnetic material on the metal layer. 
     
     
       8. The apparatus defined in  claim 6  wherein the metal layer is a cold-rolled cladding layer on the layer of magnetic shielding material. 
     
     
       9. The apparatus defined in  claim 8  wherein the layer of magnetic shielding material comprises a layer of stainless steel. 
     
     
       10. The apparatus defined in  claim 9  wherein the stainless steel comprises a stainless steel selected form the group consisting of: 430 stainless steel and 444 stainless steel. 
     
     
       11. The apparatus defined in  claim 6  wherein the layer of magnetic shielding material and the metal layer are stamped together and form walls for the shielding can. 
     
     
       12. The apparatus defined in  claim 1  wherein the layer of magnetic shielding material comprises stainless steel. 
     
     
       13. The apparatus defined in  claim 1  wherein the first and second cladding layers comprise a material selected from the group consisting of: nickel, gold, silver, and copper-nickel. 
     
     
       14. The apparatus defined in  claim 1  wherein the edge portions of the first and second cladding layers are parallel to the layer of magnetic shielding material. 
     
     
       15. The apparatus defined in  claim 1  wherein the layer of magnetic shielding material is a layer of stainless steel and the first and second cladding layers encapsulate the layer of stainless steel. 
     
     
       16. Shielded circuitry, comprising:
 a support structure; 
 electrical components soldered to the support structure; and 
 a shielding structure that shields the electrical components and that is soldered to the support structure, wherein the shielding structure comprises a stainless steel layer with opposing first and second surfaces, the stainless steel layer has a first length, a first cladding layer on the first surface, and a second cladding layer on the second surface, the first and second cladding layers have second and third lengths that are longer than the first length, the first and second cladding layers extend beyond the stainless steel layer, and edge portions of the first and second cladding layers are joined together without any intervening portions of the stainless steel layer. 
 
     
     
       17. The shielded circuitry defined in  claim 16  wherein the stainless steel layer has a relative permeability of at least 500. 
     
     
       18. The shielded circuitry defined in  claim 16  wherein the stainless steel comprises a stainless steel selected from the group consisting of: 430 stainless steel and 444 stainless steel. 
     
     
       19. The shielded circuitry defined in  claim 16  wherein the cladding layers comprise a metal with more solderability than the stainless steel layer. 
     
     
       20. The shielded circuitry defined in  claim 16  wherein the shielding structure comprises a cowling that holds the electrical components to the support structure.

Description:
This application claims the benefit of and claims priority to provisional patent application No. 62/316,436, filed Mar. 31, 2016, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to shielding and, more particularly, shielding structures such as shielding cans that provide magnetic and radio-frequency electromagnetic interference shielding. 
     BACKGROUND 
     Electronic equipment often contains components that are subject to signal interference. Metal shield cans may be used to cover integrated circuits and other components and thereby help to suppress electromagnetic interference. Shield cans of this type can be formed from materials such as copper that suppress signals at radio frequencies and may sometimes be referred to as radio-frequency shields. 
     Magnetic materials may be used to form shield cans that help suppress magnetic fields at lower frequencies. An example of a magnetic material that can be used in forming magnetic shielding cans is the high permeability nickel-iron magnetic alloy that is sometimes referred to as mu-metal. 
     To add magnetic shielding capabilities to metal radio-frequency shielding cans, a layer of mu-metal material may be attached to the surface of a metal radio-frequency shielding can with adhesive, but this type of arrangement may add undesirable bulk, can adversely affect reliability because magnetic material layers can separate from underlying radio-frequency shield cans, and can add to assembly cost and complexity. 
     SUMMARY 
     Electrical components may be shielded using a shielding can or other shielding structure that covers the electrical components. The electrical components and the shielding structure may be mounted on a substrate such as a printed circuit board using solder or other conductive material. 
     The shielding structure may have walls formed from one or more shielding layers. The shielding layers may include high conductivity material for providing shielding for radio-frequency electromagnetic interference and magnetic material for blocking magnetic flux. In some configurations, shielding may be provided using a single layer that serves both as a radio-frequency interference shield and as a magnetic shield. In multilayer configurations, cold-rolling techniques, stamping processes, electroplating and other coating techniques, and other methods for joining multiple layers of material together may be used to form shield can walls. 
     Shielding structures may be formed from materials such as stainless steel, layers that enhance solderability, corrosion resistance, and conductivity, magnetic materials that are printed or otherwise formed on underlying metal layers, and other shielding structures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional side view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a cross-sectional side view of a portion of an illustrative printed circuit board populated with electrical components that are shielded by a shield in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative shield can in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of a shielding structure such as a shield can or cowling with shielding materials in accordance with an embodiment. 
         FIG. 5  is a diagram of illustrative equipment for cold rolling a multilayer structure for a shield in accordance with an embodiment. 
         FIG. 6A  is a diagram showing how dies or other shaping equipment may be used to form one or more shielding layers into a shield of a desired shape in accordance with an embodiment. 
         FIG. 6B  is a cross-sectional side view of an illustrative shield having an inner layer that is fully isolated from outside contact by outer cladding layers in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative shield formed from a single layer of shielding material in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view of an illustrative shield formed from two layers of material in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of an illustrative shield onto which magnetic material has been incorporated using printing or other deposition techniques in accordance with an embodiment. 
         FIG. 10  is a cross-sectional side view of an illustrative shield having three layers of shielding material in accordance with an embodiment. 
         FIG. 11  is a diagram of illustrative equipment for forming shielding structures in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with electrical components such as integrated circuits, discrete electrical components such as inductors, capacitors, and resistors, and other electrical components. Shielding may be used to prevent interference between components. The shielding block radio-frequency signals and magnetic fields. Shielding structures may be formed into the shape of shielding cans and may serve as cowlings. 
     A cross-sectional side view of an illustrative electronic device of the type that may include shielded electrical components is shown in  FIG. 1 . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, an accessory (e.g., earbuds, a remote control, a wireless trackpad, etc.), or other electronic equipment. 
     As shown in  FIG. 1 , device  10  may include components such as display  14 . Display  14  may be mounted in 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.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Display  14  may be protected using a display cover layer such as display cover layer  16 . A liquid crystal display module, organic light-emitting diode display, or other display structures (shown as display module  18  in the example of  FIG. 1 ) may be mounted below display cover layer  16 . In some configurations for device  10 , display  14  may be omitted. The arrangement of  FIG. 1  in which device  10  includes display  14  is merely illustrative. 
     As shown in the cross-sectional side view of electronic device  10  of  FIG. 1 , electronic device  10  may include internal electrical components such as electrical components  22 . Electrical components  22  may include sensors, integrated circuits, buttons, connectors, discrete components such as inductors, capacitors, and resistors, and other circuitry. If desired, one or more of electrical components  22  may be a system-in-package (SiP) device. A component formed using system-in-package technology includes multiple integrated circuits packaged in a common package. 
     In the interior of electronic device  10 , electrical components  22  may be mounted on one or more substrates such as substrate  20 . Substrate  20  may be a dielectric carrier such as a molded plastic carrier, a ceramic substrate, or a printed circuit. For example, substrate  20  may be a printed circuit such as a rigid printed circuit formed from a material such as fiberglass-filled epoxy or may be a flexible printed circuit formed from a sheet of polyimide or other flexible polymer layer. 
     To block radio-frequency electromagnetic signal interference (EMI) and magnetic fields, electrical components  22  may be covered with shields such as shield  24 . Shield  24  may have the shape of a shielding can with a top and four sides or other suitable shape, may serve as a cowling, bracket, or other part that helps to hold portions of device  10  together while shielding electrical components  22 , or may be formed from other suitable shielding structures. 
     Shields such as shield  24  may cover one or more electrical components  22 . If desired, some of the electrical components on substrate  20  may be uncovered by shielding structures (see, e.g., unshielded electrical component  22 NC). Shield  24  may be coupled to metal traces (e.g., grounding traces) on substrate  20  using solder, welds, conductive adhesive, screws or other fasteners, or other conductive attachment structures. Shields  24  may be used to cover aggressor components and thereby block the emission of interfering signals and may be used to cover sensitive (victim) components and thereby prevent interference from disrupting those components. 
     A cross-sectional side view of an illustrative set of components  22  that have been covered by a shield such as shield  24  is shown in  FIG. 2 . As illustrated by the shielded circuitry of  FIG. 2 , components  22  and shield  24  may be mounted to substrate  20  using conductive material such as solder  30 . Substrate  20  may be a printed circuit or other substrate that includes one or more layers of signal interconnects  32  (e.g., one or more layers of patterned metal traces). Interconnects  32  may include contacts such as solder pads  32 P. Pads  32 P may be formed on the upper surface of substrate  20  (as an example). Contacts formed from interconnects  32  may also be located on the lower surface of substrate  20  (e.g., to facilitate mounting of electrical components  22  and additional shields such as shield  24  to the lower surface printed circuit  20 ). Pads  32 P and other interconnects  32  may be used to couple shield  24  to ground, may be used to route data between electrical components  22 , may be used to distribute power supply signals and other signals, etc. 
     Electrical components  22  may have contacts such as solder pads  22 P that mate with contacts  32 P on the upper surface of printed circuit  20 . A soldering tool or other equipment may use solder  30  or other conductive material (e.g., conductive adhesive, etc.) to mount electrical components  22  and one or more shields such as shield  24  to pads  32 P on substrate  20 . After integrated circuits and other electrical components  22  have been mounted to substrate  20 , components  22  may, if desired, be covered with thermally conductive material  34  such as thermal compound (thermal grease), thermally conductive foam, or other thermally conductive material. Thermally conductive material  34  may help promote heat transfer away from components  22  through shield  24  (e.g., to a heat sink, to a region with flowing air, etc.). 
     Shield  24  may have one or more layers of material such as layers  24 L. To provide components  22  with satisfactory electromagnetic shielding, shield  24  may contain conductive materials (e.g., to block electromagnetic interference at radio frequencies) and/or magnetic materials (to block magnetic flux). As an example, metals and other materials that form shield  24  may exhibit high conductivity and high permeability. The resistivity of a high-conductivity metal of the type that may be used in shield  24  to provide shield  24  with radio-frequency shielding capabilities may be less than 2×10 −8  ohm-m, less than 3×10 −8  ohm-m, less than 10×10 −8  ohm-m, or other suitable amount. The relative permeability of the layer(s) of magnetic material in layer  40  and/or layer  31  may be 500 or more, may be 2000 or more, may be 5000 or more, may be 10,000 or more, may be 20,000 or more, may be 80,000 or more, may be 5,000-100,000, may be 50,000-100,000, be less than 100,000, or may have any other suitable value that allows material to serve as magnetic shielding for components  22 . Layers  40 L may include one or more layers that primarily provide magnetic shielding, one or more layers that primarily provide radio-frequency electromagnetic shielding, one or more layers that serve both as magnetic shielding and as radio-frequency shielding, and one or more layers that provide shield  24  with other desirable attributes (solderability, corrosion resistance, heat transfer capabilities, enhanced conductivity, etc.). 
     Shield  24  may have any suitable shape such as a square shape, a rectangular shape, a shape with an irregular outline, a shape with multiple different heights above substrate  20 , a shape with curved edges, and/or other suitable shapes). As shown in the perspective view of the illustrative shield  24  of  FIG. 3 , shield  24  may, if desired, have the shape of a shield can with a planar top surface  24 T and vertical sidewalls  24 W. With this type of arrangement, the shield can may have the shape of an open-bottomed box that can be mounted on substrate  20  to enclose one or more electrical components  22  mounted on substrate  20 . Shield cans with other shapes may also be used to shield components  22 . 
     If desired, device  10  may have mechanical structures such as brackets, clamps, and frame structures, and other structures that help attach portions of device  10  together or that serve other mechanical functions. The materials of shield  24  such as layers  24 L of  FIG. 2  may, if desired, be incorporated into a cowling structure that helps hold connectors, integrated circuits, or other electrical components in place on a printed circuit board or other substrate.  FIG. 4  is a cross-sectional side view of an illustrative cowling of the type that may be formed from materials that allow the cowling to serve as a shield. As shown in  FIG. 4 , cowling  24 C may overlap components  22  and may press downward on components  22  to help hold components  22  in place on support structure  20 T. Support structure  20 T may be a substrate such as a printed circuit, may be a metal bracket, a housing wall, an internal housing member, a ceramic or plastic member, or other suitable structure in device  10 . In the example of  FIG. 4 , screws  40  have threads that engage mating threads in support structure  20 T and thereby secure cowling  24 C in place on structure  20 T. This is merely illustrative. Cowling  24 C may be mounted on structure  20 T using any suitable attachment mechanisms (solder joints, welds, adhesive, fasteners other than screws, etc.). Cowling  24 C may include one or more layers such as layers  24 L of  FIG. 2  so that cowling  24 C may serve as a shield for components  22  that are covered by cowling  24 C. In general, any suitable structures may be used to provide components  22  with shielding. The use of cowling  24 C of  FIG. 4  is merely illustrative. Configurations in which components  22  are shielded using a shield structure such as shield  24  of  FIG. 3  may sometimes be described herein as an example. 
     In configurations in which shield  24  is formed from a single layer of material, it may be desirable to form shield  24  from a material that has both radio-frequency and magnetic shielding capabilities while offering suitable corrosion resistance and solderability. With one illustrative arrangement, shield  24  may be formed from a stainless steel such as 444 stainless steel or 430 stainless steel (e.g., stainless steel with a relative permeability of 600-1100 or more), or other stainless steels (e.g., other 400 series stainless steels, other stainless steels with relative permeabilities of 500 or more, 600 or more, 1000 or more, etc.). Stainless steels such as these may exhibit both satisfactory conductivity (e.g., resistance less than 65×10 −8  ohm-m, less than less than 2×10 −8  ohm-m, less than 3×10 −8  ohm-m, less than 10×10 −8  ohm-m, or other suitable amount) and satisfactory magnetic permeability (e.g., a relative permeability of 500 or more, 600 or more, 1000 or more, etc.). 
     If desired, layers  20 L may include one or more layers such as a pair of outer layers that exhibit good solderability and corrosion resistance (and, if desired, enhanced conductivity for radio-frequency shielding) and one or more inner layers such as stainless steel that can serve as radio-frequency and magnetic shielding. As an example, a layer of stainless steel (e.g., 430 stainless, 444 stainless, other stainless steel, etc.) may be incorporated into shield  24  between a pair of layers of corrosion resistant metal or metal alloy material (e.g., nickel or an alloy such as copper-nickel) using a cold rolling process. 
     Illustrative cold rolling equipment is shown in  FIG. 5 . As shown in  FIG. 5 , cold rolling equipment  50  may include rollers such dispensing rollers  52 ,  54 , and  58  and compression rollers such as rollers  56 . Roller  52  may dispense inner layer  24 L- 2 . Rollers  58  and  54  may respectively dispense outer layers  24 L- 1  and  24 L- 3 . Inner layer  24 L- 2  may serve as radio-frequency shielding and/or magnetic shielding. Layer  24 L- 2  may be, for example, stainless steel such as 444 stainless steel, 430 stainless steel (e.g., stainless steel with a relative permeability of 600-1100 or more), or other stainless steels (e.g., other 400 series stainless steels, other stainless steels with relative permeabilities of 500 or more, 600 or more, 1000 or more, etc.). Outer layers  24 L- 1  and  24 L- 3  serve as cladding and may help provide layer  24 L- 2  with enhanced corrosion resistance and/or enhanced solderability. Layers  24 L- 1  and  24 L- 3  may be, for example, layers of nickel or layers of copper-nickel (e.g., 90-70% copper and 10-30% nickel, etc.). Other materials may be used for outer layers  24 L- 1  and  24 L- 3  and other materials may be used for inner layer  24 L- 2 , if desired. 
     As part of a cold rolling process, rollers  56  may compress layers  24 L- 1 ,  24 L- 2 , and  24 L- 3  together to from combined layers  24 L of shield  24 . After compression (and, if desired, annealing), layers  24 L- 1  and  24 L- 3  (e.g., layers of gold, copper-nickel, nickel, silver, or other materials) serve as cladding layers on opposing sides of layer  24 L- 2  (e.g., a magnetic shielding material layer). If desired, stamping, laser cutting, machining, and/or other cutting and shaping techniques may be used to form cold-rolled layers  24 L of  FIG. 5  into a desired shield structure (e.g., shielding can  24  of  FIG. 3 , cowling  24 C of  FIG. 4 , etc.). Cold rolling techniques may be used to produce continuous rolls of clad stainless steel shielding material or may be used to produce discrete sections of shielding material with desired cladding layers. 
     As shown in  FIG. 6A , a metal forming tool such as a stamping die tool may be used to cut and/or form metal layer(s)  24 L into desired shield structures. In the example of  FIG. 6A , stamping tool  60  may include dies such as upper die  60 T and lower die  60 L. When dies  60 T and  60 L are moved towards each other in directions  62 , layers  24 L can be formed into a desired shape for forming shield  24 . A single layer  24 L (e.g., a stainless steel layer or other suitable layer) may be shaped using tool  60  or multiple layers  24 L may be shaped using tool  60 . The outer layers among layers  24 L may serve as cladding layers for one or more inner layers. These layers may be clad onto inner layer(s)  24 L using cold rolling equipment  50  of  FIG. 5  (e.g., before stamping) or may be clad onto inner layer(s)  24 L when using stamping tool  60 . As shown in  FIG. 6B , shield  24  may be formed from outer cladding layers such as outer cladding layers  24 LT that are larger than an inner layer such as inner layer  24 LC. If, as an example, layers  24 LT are rectangular and have dimensions L 1 ×L 2 , layer  24 LC may be formed with a smaller rectangular shape having dimensions L 1 ′×L 2 ′, where L 1 ′&lt;L 1  and L 2 ′&lt;L 2 . Inner layer  24 LC may be cut from a layer of material using a stamping tool or other cutting equipment and may be sandwiched between outer layers  24 LC and formed into shape using dies such as dies  60 T and  60 L of  FIG. 6A . If desired, layers  24 LC may be cut from larger sheets of material using dies such as dies  60 T and  60 L (e.g., as part of a stamping process that forms shield  24  into a desired shape or as part of a separate cutting operation). Because inner layer  24 LC has smaller lateral dimensions than outer layers  24 LT, lower edges  61  of shield  24  will contain only the material of outer layers  24 LT and will be free of the material of inner layer  24 LC (i.e., because the outer cladding layers of shield  24  are larger than the inner layer of magnetic shielding material, edge portions of the cladding layers are joined together without any intervening portions of the magnetic shielding material). This may help prevent corrosion of inner layer  24 LC and enhance solderability of the lower edges of shield  24 . Central region  63  of shield  24  contains inner layer  24 LC, so inner layer  24 LC may be used in shielding components that are overlapped by shield  24 . Any suitable materials may be used in forming the inner and outer layers of shields  24  of  FIGS. 6A and 6B . For example, the outer layers of shields  24  of  FIGS. 6A and 6B  may be formed from materials that enhance corrosion resistance and/or solderability, such as the materials used for layers  24 L- 1  and  24 L- 3  of  FIG. 5  and the inner layers of shields  24  of  FIGS. 6A and 6B  may be formed from magnetic materials such as the materials used for layer  24 L- 2  of  FIG. 5 . If desired, other techniques for cutting and forming layer(s) of material into a desired shape for shield  24  may be used, if desired. The examples of  FIGS. 5, 6A and 6B  are merely illustrative. 
     If desired, magnetic materials or other shielding materials may be added onto a shield structure using printing (e.g., screen printing, pad printing, ink-jet printing, etc.) or other techniques. As an example, particles of magnetic material in a curable liquid resin (e.g., a curable liquid polymer) may be printed onto the upper surface of a shield can and cured (e.g., by application of heat to cure a thermally curable resin, by application of ultraviolet light to cure an ultraviolet-light-cured resin, etc.). 
       FIGS. 7, 8, 9, and 10  are cross-sectional side views of shield  24  in various illustrative configurations. The thicknesses of the walls of shield  24  in the illustrative configurations of  FIGS. 7, 8, 9, and 10  may be 100-200 microns, more than 125 microns, less than 250 microns, or other suitable thickness. 
     In the configuration of  FIG. 7 , shield  24  has been formed from a single layer of material (layer  24 L). The single layer of material may have sufficient magnetic permeability and sufficient conductivity to serve both as a magnetic flux shield and a radio-frequency electromagnetic interference shield. Layer  24 L may be, for example, a stainless steel layer. 
     In the arrangement of  FIG. 8 , a first layer ( 24 LA) has been attached to a second layer ( 24 LB) to form shield  24 . One of layers  24 LA and  24 LB may have a high conductivity and the other of layers  24 LA and  24 LB may have a high relative permeability (i.e., one of these layers may serve as a radio-frequency shielding layer and the other of the layers may serve as a magnetic shielding layer). If desired, one of the layers may be stainless steel layer (e.g., 430 stainless steel, 444 stainless steel, other ferritic stainless steel, etc.) and the other of the layers may be formed from a material with satisfactory corrosion resistance and/or solderability (e.g., nickel, copper-nickel, gold, silver, etc.). Layers  24 LA and  24 LB may be rolled together using cold rolling techniques, may be stamped together, etc. Stamping equipment  60  or other equipment may be used for shaping shield  24  from layers  24 L. 
     In the arrangement of  FIG. 9 , a first layer ( 24 LA) has been printed on a second layer ( 24 LB) to form shield  24 . Any suitable printing technique or other deposition technique may be used to deposit layer  24 LA on layer  24 LB. Layer  24 LA may be, for example, printed onto layer  24 LB using screen printing, pad printing, or ink-jet printing, or may be applying using spraying, dipping, or other techniques. Layer  24 LA may extend across the top and sidewalls of layer  24 LB (see, e.g., central portion  24 LA- 1  and sidewall portions  24 LA- 2 ) or may be confined to the planar upper surface of layer  24 LB (see, e.g., central portion  24 LA- 1 ). Layer  24 LB may be a stainless steel layer that can block magnetic flux while providing electromagnetic radio-frequency shielding or may be a high-conductivity metal radio-frequency electromagnetic shielding layer. Layer  24 LA may be a layer of magnetic material that can serve as a magnetic shield (i.e., layer  24 LA can block magnetic flux and may have a relative permeability of 500 or more 1000 or more, or other suitable value). 
       FIG. 10  is a cross-sectional side view of an illustrative shield having three layers of material. As shown in  FIG. 10 , shield  24  may include first layer  24 L- 1 , second layer  24 L- 2 , and third layer  24 L- 3 . Layer  24 L- 2  may be a magnetic shielding layer such as a layer of stainless steel and outer layers  24 L- 1  and  24 L- 3  may be layers of nickel, copper-nickel, silver, gold or other materials that enhance solderability and corrosion resistance. Outer layers  24 L- 1  and  24 L- 3  may be cold-rolled or stamped cladding layers, may be electroplated coatings or coatings deposited using physical vapor deposition, or may be other outer layers. If desired, inner layer  24 L- 2  may be formed using multiple sublayers (e.g., a high conductivity electromagnetic interference shielding layer and a magnetic shielding layer formed from a magnetic material). Configurations with additional layers may also be used in forming shield  24 . The configuration of  FIG. 10  is merely illustrative. 
       FIG. 11  shows illustrative operations involved in fabricating a device with shielded components. Initially, one or more layers  24 L of material may be shaped using shaping tool  60  (e.g., a press or other tool such as stamping tool  60  of  FIG. 6A ) to form shaped layer(s)  24 LB. Layer(s)  24 LB may include one or more radio-frequency shielding layers, one or more magnetic shielding layers, one or more layers that serve both as radio-frequency shielding layers and magnetic shielding layers, one or more corrosion resistance and/or solderability enhancement layers, and/or other layer(s) of material. 
     Shaped layer  24 LB may be processed using deposition equipment such as deposition tool  70  to form shield  24 . Tool  70  may deposit optional additional layer(s) of material such as layer  24 LA on one or both sides of layer  24 LB using printing (e.g., printing of magnetic material on central region  24 LA- 1  and/or side regions  24 LA- 2 ), using electrochemical deposition (plating), using physical vapor deposition, or using other deposition techniques. The additional layer(s)  24 A may be corrosion resistance layers (e.g., nickel, copper-nickel etc.), may be layers of gold, silver, or other high conductivity and/or corrosion resistance materials, and or may be other materials (e.g., magnetic materials). Configurations in which layer  24 LB is formed from multiple cold-rolled layers (see, e.g.,  FIG. 5 ) and/or multiple layers that have been stamped together using equipment such as tool  60  of  FIG. 6A  or other equipment, may also be used. 
     After forming shield  24 , equipment  72  may be used to mount shield  24  on substrate  20  to shield electrical components  22  and to assemble substrate  20  with other structures in housing  12  to form device  10 . Equipment  72  may include surface mount technology (SMT) soldering equipment and other equipment for attaching shield  24  and components  22  to substrate  20 , computer-controlled equipment for assembling display cover layer  16  and display module  18  in housing  12 , and other equipment for assembling device  10 . 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20160829
Publication Date: 20190305
Grant Date: 20190305
Priority Date: 20160331
Inventors: SMITH, JAMES B.
JARVIS, DANIEL W.
PAKULA, DAVID A.
STEPHENS, GREGORY N.
MERZ, NICHOLAS G. L.
MALEK, SHAYAN
BIGDELI, SINA
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K9/003", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0024", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/16152", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73253", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/16152", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/73253", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16225", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K9/003", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0031", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 59959993