Patent Publication Number: US-2023163458-A1

Title: Electromagnetic shielding using an outer cobalt layer

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57 and should be considered a part of this specification. 
     BACKGROUND 
     Field 
     Embodiments of the invention relate to electronic systems, and in particular, to radio frequency electronics. 
     Description of Related Technology 
     Radio frequency (RF) communication systems can be used for transmitting and/or receiving signals of a wide range of frequencies. For example, an RF communication system can be used to wirelessly communicate RF signals in a frequency range of about 30 kHz to 300 GHz. 
     Examples of RF communication systems include, but are not limited to, mobile phones, tablets, base stations, network access points, customer-premises equipment (CPE), laptops, and wearable electronics. 
     SUMMARY 
     In accordance with one aspect of the disclosure, a packaged radio frequency module is provided. The packaged radio frequency module comprises a package substrate and at least one semiconductor die attached to the package substrate and including one or more radio frequency circuits. A molding compound encapsulates the at least one semiconductor die. An electromagnetic shielding structure at least partially covers the molding compound, the electromagnetic shielding structure having an outer layer including cobalt. 
     In accordance with another aspect of the disclosure, a phone board assembly is provided that comprises a printed circuit board and a packaged radio frequency module attached to the printed circuit board. The radio frequency module comprises a package substrate and at least one semiconductor die attached to the package substrate and including one or more radio frequency circuits. An electromagnetic shielding structure at least partially encloses the at least one semiconductor die, the electromagnetic shielding structure having an outer layer including cobalt. 
     In accordance with another aspect of the invention, a mobile device is provided. The mobile device comprises a transceiver configured to generate a radio frequency transmit signal and to receive a radio frequency receive signal. The mobile device also comprises a front end system configured to process the radio frequency transmit signal from the transceiver and to provide the transceiver with the radio frequency receive signal. The front end system includes a packaged radio frequency module including a package substrate. At least one semiconductor die is attached to the package substrate and includes one or more radio frequency circuits. An electromagnetic shielding structure at least partially encloses the at least one semiconductor die, the electromagnetic shielding structure having an outer layer including cobalt. 
     In accordance with another aspect of the disclosure, a radio frequency module is provided. The module comprises a semiconductor die including one or more radio frequency circuits fabricated therein, and an electromagnetic shielding structure at least partially enclosing the semiconductor die, the electromagnetic shielding structure having an outer layer including cobalt. 
     In accordance with another aspect of the disclosure, a method of forming a packaged radio frequency module is provided. The method comprises the steps of: attaching at least one semiconductor die to a package substrate, the at least one semiconductor die including one or more radio frequency circuits, encapsulating the at least one semiconductor die in a molding compound, and forming an electromagnetic shielding structure over the molding compound, including providing cobalt in an outer layer of the electromagnetic shielding structure. 
     In accordance with another aspect of the disclosure, a method of shielding a radio frequency component is provided. The method comprises forming an electromagnetic shielding structure over a semiconductor die, said forming step including providing cobalt in an outer layer of the electromagnetic shielding structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
         FIG.  1    is a schematic diagram of one example of a communication network. 
         FIG.  2    is a schematic diagram of a packaged radio frequency (RF) component according to one embodiment. 
         FIG.  3 A  is a schematic diagram of a packaged RF module according to one embodiment. 
         FIG.  3 B  is a schematic diagram of a phone board according to one embodiment. 
         FIG.  4 A  is a plan view of one embodiment of a packaged RF module. 
         FIG.  4 B  is a schematic diagram of a cross-section of the packaged RF module of  FIG.  4 A  taken along the lines  4 B- 4 B. 
         FIG.  5    is a cross-section of another embodiment of a packaged RF module. 
         FIG.  6    is a front perspective view of one embodiment of another embodiment of a phone board. 
         FIG.  7    is a plan view of another embodiment of a packaged RF component. 
         FIG.  8    is a plan view of another embodiment of a phone board. 
         FIG.  9    is a schematic diagram of one embodiment of a mobile device. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings. 
     The International Telecommunication Union (ITU) is a specialized agency of the United Nations (UN) responsible for global issues concerning information and communication technologies, including the shared global use of radio spectrum. 
     The 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications standard bodies across the world, such as the Association of Radio Industries and Businesses (ARM), the Telecommunications Technology Committee (TTC), the China Communications Standards Association (CCSA), the Alliance for Telecommunications Industry Solutions (ATIS), the Telecommunications Technology Association (TTA), the European Telecommunications Standards Institute (ETSI), and the Telecommunications Standards Development Society, India (TSDSI). 
     Working within the scope of the ITU, 3GPP develops and maintains technical specifications for a variety of mobile communication technologies, including, for example, second generation (2G) technology (for instance, Global System for Mobile Communications (GSM) and Enhanced Data Rates for GSM Evolution (EDGE)), third generation (3G) technology (for instance, Universal Mobile Telecommunications System (UMTS) and High Speed Packet Access (HSPA)), and fourth generation (4G) technology (for instance, Long Term Evolution (LTE) and LTE-Advanced). 
     The technical specifications controlled by 3GPP can be expanded and revised by specification releases, which can span multiple years and specify a breadth of new features and evolutions. 
     In one example, 3GPP introduced carrier aggregation (CA) for LTE in Release 10. Although initially introduced with two downlink carriers, 3GPP expanded carrier aggregation in Release 14 to include up to five downlink carriers and up to three uplink carriers. Other examples of new features and evolutions provided by 3GPP releases include, but are not limited to, License Assisted Access (LAA), enhanced LAA (eLAA), Narrowband Internet-of-Things (NB-IOT), Vehicle-to-Everything (V2X), and High Power User Equipment (HPUE). 
     3GPP plans to introduce Phase 1 of fifth generation (5G) technology in Release 15 (targeted for 2018) and Phase 2 of 5G technology in Release 16 (targeted for 2019). Release 15 is anticipated to address 5G communications at less than 6 GHz, while Release 16 is anticipated to address communications at 6 GHz and higher. Subsequent 3GPP releases will further evolve and expand 5G technology. 5G technology is also referred to herein as 5G New Radio (NR). 
     Preliminary specifications for 5G NR support a variety of features, such as communications over millimeter wave spectrum, beam forming capability, high spectral efficiency waveforms, low latency communications, multiple radio numerology, and/or non-orthogonal multiple access (NOMA). Although such RF functionalities offer flexibility to networks and enhance user data rates, supporting such features can pose a number of technical challenges. 
     The teachings herein are applicable to a wide variety of communication systems, including, but not limited to, communication systems using advanced cellular technologies, such as LTE-Advanced, LTE-Advanced Pro, and/or 5G NR. 
       FIG.  1    is a schematic diagram of one example of a communication network  10 . The communication network  10  includes a macro cell base station  1 , a small cell base station  3 , and various examples of user equipment (UE), including a first mobile device  2   a , a wireless-connected car  2   b , a laptop  2   c , a stationary wireless device  2   d , a wireless-connected train  2   e , and a second mobile device  2   f.    
     Although specific examples of base stations and user equipment are illustrated in  FIG.  1   , a communication network can include base stations and user equipment of a wide variety of types and/or numbers. 
     For instance, in the example shown, the communication network  10  includes the macro cell base station  1  and the small cell base station  3 . The small cell base station  3  can operate with relatively lower power, shorter range, and/or with fewer concurrent users relative to the macro cell base station  1 . The small cell base station  3  can also be referred to as a femtocell, a picocell, or a microcell. Although the communication network  10  is illustrated as including two base stations, the communication network  10  can be implemented to include more or fewer base stations and/or base stations of other types. 
     Although various examples of user equipment are shown, the teachings herein are applicable to a wide variety of user equipment, including, but not limited to, mobile phones, tablets, laptops, IoT devices, wearable electronics, customer premises equipment (CPE), wireless-connected vehicles, wireless relays, and/or a wide variety of other communication devices. Furthermore, user equipment includes not only currently available communication devices that operate in a cellular network, but also subsequently developed communication devices that will be readily implementable with the inventive systems, processes, methods, and devices as described and claimed herein. 
     The illustrated communication network  10  of  FIG.  1    supports communications using a variety of technologies, including, for example, 4G LTE, 5G NR, and wireless local area network (WLAN), such as Wi-Fi. Although various examples of communication technologies have been provided, the communication network  10  can be adapted to support a wide variety of communication technologies. 
     Various communication links of the communication network  10  have been depicted in  FIG.  1   . The communication links can be duplexed in a wide variety of ways, including, for example, using frequency-division duplexing (FDD) and/or time-division duplexing (TDD). FDD is a type of radio frequency communications that uses different frequencies for transmitting and receiving signals. FDD can provide a number of advantages, such as high data rates and low latency. In contrast, TDD is a type of radio frequency communications that uses about the same frequency for transmitting and receiving signals, and in which transmit and receive communications are switched in time. TDD can provide a number of advantages, such as efficient use of spectrum and variable allocation of throughput between transmit and receive directions. 
     In certain implementations, user equipment can communication with a base station using one or more of 4G LTE, 5G NR, and Wi-Fi technologies. In certain implementations, enhanced license assisted access (eLAA) is used to aggregate one or more licensed frequency carriers (for instance, licensed 4G LTE and/or 5G NR frequencies), with one or more unlicensed carriers (for instance, unlicensed Wi-Fi frequencies). 
     The communication links can operate over a wide variety of frequencies. In certain implementations, communications are supported using 5G NR technology over one or more frequency bands that are less than 6 Gigahertz (GHz) and/or over one or more frequency bands that are greater than 6 GHz. In one embodiment, one or more of the mobile devices support a HPUE power class specification. 
     In certain implementations, a base station and/or user equipment communicates using beamforming. For example, beamforming can be used to focus signal strength to overcome path losses, such as high loss associated with communicating over high signal frequencies. In certain embodiments, user equipment, such as one or more mobile phones, communicate using beamforming on millimeter wave frequency bands in the range of 30 GHz to 300 GHz and/or upper centimeter wave frequencies in the range of 6 GHz to 30 GHz, or more particularly, 24 GHz to 30 GHz. 
     Different users of the communication network  10  can share available network resources, such as available frequency spectrum, in a wide variety of ways. 
     In one example, frequency division multiple access (FDMA) is used to divide a frequency band into multiple frequency carriers. Additionally, one or more carriers are allocated to a particular user. Examples of FDMA include, but are not limited to, single carrier FDMA (SC-FDMA) and orthogonal FDMA (OFDMA). OFDMA is a multicarrier technology that subdivides the available bandwidth into multiple mutually orthogonal narrowband subcarriers, which can be separately assigned to different users. 
     Other examples of shared access include, but are not limited to, time division multiple access (TDMA) in which a user is allocated particular time slots for using a frequency resource, code division multiple access (CDMA) in which a frequency resource is shared amongst different users by assigning each user a unique code, space-divisional multiple access (SDMA) in which beamforming is used to provide shared access by spatial division, and non-orthogonal multiple access (NOMA) in which the power domain is used for multiple access. For example, NOMA can be used to serve multiple users at the same frequency, time, and/or code, but with different power levels. 
     Enhanced mobile broadband (eMBB) refers to technology for growing system capacity of LTE networks. For example, eMBB can refer to communications with a peak data rate of at least 10 Gbps and a minimum of 100 Mbps for each user. Ultra-reliable low latency communications (uRLLC) refers to technology for communication with very low latency, for instance, less than 2 milliseconds. uRLLC can be used for mission-critical communications such as for autonomous driving and/or remote surgery applications. Massive machine-type communications (mMTC) refers to low cost and low data rate communications associated with wireless connections to everyday objects, such as those associated with Internet of Things (IoT) applications. 
     The communication network  10  of  FIG.  1    can be used to support a wide variety of advanced communication features, including, but not limited to, eMBB, uRLLC, and/or mMTC. 
       FIG.  2    is a schematic diagram of a packaged RF component  12  according to one embodiment. The packaged RF component  12  includes a semiconductor die or integrated circuit (IC)  22 . Additionally, the packaged RF component  12  includes an electromagnetic shielding structure  13  that partially encloses the IC  22  and that includes an outer layer  15  including cobalt. 
     Although one example of a packaged RF component is shown in  FIG.  2   , the teachings herein are applicable to packaged RF components and modules implemented in a wide variety of ways. 
     In the illustrated embodiment, the outer layer  15  extends over a top surface of the IC  22 , and does not extend along the sides of the electromagnetic shielding structure  13 . However, other implementations are possible, such as configurations in which the outer layer  15  also extends along at least one side of the electromagnetic shielding structure  13 . 
     The IC  22  includes an RF circuit  27 , which can be implemented in a wide variety of ways. For example, the RF circuit  27  can include one or more RF amplifiers, RF filters, RF switches, and/or other RF circuitry. Although the IC  22  is illustrated as including one RF circuit, the IC  22  can include additional RF circuits as well as other structures and/or circuits, including, but not limited to, analog and/or digital circuitry. 
     The electromagnetic shielding structure  13  operates to provide electromagnetic shielding to the RF circuit  27 . For example, the electromagnetic shielding structure  13  can operate as a Faraday cage, thereby inhibiting or attenuating propagation of electromagnetic waves. As persons having ordinary skill in the art will appreciate, an electromagnetic shield need not fully block electromagnetic energy, but rather can reduce or attenuate electromagnetic fields over one or more frequency ranges. 
     The electromagnetic shielding structure  13  includes the outer layer  15 , which includes cobalt. By including an outer layer of cobalt, a number of advantages can be achieved. 
     For example, cobalt can provide electromagnetic shielding at certain frequency ranges. In certain implementations, an outer cobalt layer provides shielding over a frequency range that includes at least 1 megahertz (MHz) to 5 MHz, or more particularly, at least 100 kilohertz (kHz) to 5 MHz. Providing electromagnetic shielding in this frequency range can provide a number of advantages, including, but not limited to, shielding the RF circuit  27  from electromagnetic emissions from a wireless charging circuit. 
     In contrast certain conventional electromagnetic shielding structures may not shield at a low end of radio frequency spectrum, for instance, at frequencies less than about 5 MHz. 
     Certain electromagnetic shielding structures herein include one or more inner layers for providing electromagnetic shielding over one or more high frequency ranges, and an outer cobalt layer that provides electromagnetic shield over a lower frequency range, for instance, a frequency range covering at least 1 MHz to 5 MHz, and more particularly 100 kHz to 5 MHz. By implementing the electromagnetic shielding structure in this manner, wideband shielding of electromagnetic energy is achieved. 
     By implemented an RF communication device using packaged RF components and/or modules that include electromagnetic shielding structures with wideband shielding provides a number of benefits, including, but not limited to, an ability to transmit and/or receive RF signals in noisy radio environments, over greater distances, and/or while a battery of the RF communication device is being wirelessly charged. 
     Including cobalt in the outer layer  15  also can provide the packaged RF component  12  with a blue color. For instance, in certain implementations, the outer layer  15  presents as a blue color, such as a red-green-blue (RGB) value including a red component of about 0, a green component of about 71, and a blue component of about 171. However, the outer layer  15  can present other colors. 
     The blue color can provide a number of benefits. For example, in certain implementations, high performance parts, such as those complying with a particular communication standard (for instance, 5G), are implemented with an electromagnetic shielding having an outer layer of cobalt for enhanced performance. 
     Such blue color RF components and modules can be easily identified by sight, not only during manufacture, assembly, and/or test, but also after inclusion in an RF communication device (for instance, on a circuit board). For example, the blue color can provide contrast, to black, grey, and/or silver components typically associated with electronics. 
     Moreover, when manufacturing certain RF communication devices, such as mobile phones, multiple RF components or modules can be placed on a tape, which in turn can be placed on a reel for facilitating assembly line manufacturing. The blue color can readily distinguish a tape and reel including components or modules shielded with an outer cobalt layer from the tape and reel of other RF components or modules, thereby reducing operator error. 
     The outer layer  15  can be formed in a wide variety of ways, including, but not limited to, using sputtering. In certain implementations, the outer layer  15  is formed substantially of cobalt. In another embodiment, the outer layer  15  includes at least fifty percent cobalt by mass, or more particularly, at least ninety percent cobalt by mass. 
       FIG.  3 A  is a schematic diagram of a packaged RF module  20  according to one embodiment. The packaged RF component  20  includes a package substrate  21 , a semiconductor die or IC  22 , an electromagnetic shielding structure  23 , and a molding compound  24 . 
     As shown in  FIG.  3 A , the semiconductor die  22  is attached to package substrate  21 , and the molding compound  24  encapsulates the semiconductor die  22 . Although an example with one IC attached to the package substrate is shown, the IC can include multiple dies and/or other components (including, but not limited to, surface mount devices, integrated passive devices, and/or or filters) integrated on and/or within the package substrate  21 . 
     The electromagnetic shielding structure  23  partially covers the molding compound  24 , and includes an outer layer  31  that includes cobalt. In this embodiment, the outer layer  31  extends both along the top of the IC  22 , as well as laterally around a perimeter of the IC  22 . Thus, the electromagnetic shielding structure  23  serves as a lid that encloses the IC  22  when the lid is positioned against the package substrate  21 . Although another example of an electromagnetic shielding structure is shown in  FIG.  3 A , the teachings herein are applicable to electromagnetic shielding structures implemented in a wide variety of ways. 
     The illustrated electromagnetic shielding structure  23  includes multiple layers, including not only the outer layer  31 , but also a first inner layer  35  and a second inner layer  36 . As shown in  FIG.  3 A , the second inner layer  36  is positioned between the first inner layer  35  and the outer layer  31 . Although a three layer electromagnetic shielding structure is shown, an electromagnetic shielding structure can include more or fewer layers. 
     The first inner layer  35  and the second inner layer  36  can be implemented in a wide variety of ways. In a first example, the first inner layer  35  includes titanium and the second inner layer  36  includes copper. In a second example, the first inner layer  35  includes cobalt and the second inner layer  36  includes copper. Including one or more inner cobalt layers can provide a number of benefits, such as superior electromagnetic shielding in a low frequency RF range and/or reduced cost or time of manufacture by reducing changes and/or retooling of manufacturing apparatus (for instance, sputtering equipment). 
       FIG.  3 B  is a schematic diagram of a phone board  40  according to one embodiment. The phone board  40  includes an RF module  20  attached thereto. The packaged RF module  20  can be as described above with respect to  FIG.  3 A . The phone board  40  further includes additional RF components  37 ,  38 . Although two additional RF components are shown, the phone board  40  can include a wide variety of structures attached thereto, including but not limited to, additional RF components. 
     The electromagnetic shielding structure  23  of the packaged RF module  22  includes the outer layer  31 , which includes cobalt. In certain implementations, the outer layer  31  presents a blue color to thereby distinguish the packaged RF module  22  from the RF components  37 ,  38  and/or one or more other RF components or modules attached to the phone board  40 . Thus, not only does the outer cobalt layer provide enhanced electromagnetic shielding performance, but also aids in distinguishing the packaged RF module  22  from other circuitry, thereby aiding in manufacture, testing, and/or repair of the phone board  40 . 
     In certain implementations, the phone board  40  includes a wireless charging circuit, and the outer layer  31  of the electromagnetic shielding structure  23  operates to shield the RF circuit  27  from electromagnetic emissions of the wireless charging circuit. 
       FIG.  4 A  is a plan view of one embodiment of a packaged RF module  100 .  FIG.  4 B  is a schematic diagram of a cross-section of the packaged RF module  100  of  FIG.  4 A  taken along the lines  4 B- 4 B. 
     Certain implementations of the RF communication systems herein include one or more packaged RF modules, such as the packaged RF module  100 . Although the packaged RF module  100  of  FIGS.  4 A and  4 B  illustrates one example implementation of a module suitable for use in an RF communication system, other implementations of modules are possible. 
     The packaged RF module  100  includes radio frequency components  101 , a semiconductor die  102 , surface mount devices  103 , wirebonds  108 , a package substrate  120 , encapsulation structure or molding compound  140 , and an electromagnetic shielding structure  150 . The package substrate  120  includes pads  106  formed from conductors disposed therein. Additionally, the semiconductor die  102  includes pins or pads  104 , and the wirebonds  108  have been used to connect the pads  104  of the die  102  to the pads  106  of the package substrate  120 . 
     As shown in  FIG.  4 B , the packaged RF module  100  is shown to include a plurality of contact pads  132  disposed on the side of the packaged RF module  100  opposite the side used to mount the semiconductor die  102 . Configuring the packaged RF module  100  in this manner can aid in connecting the packaged RF module  100  to a circuit board, such as a phone board of a wireless device. The example contact pads  132  can be configured to provide radio frequency signals, bias signals, and/or power (for example, a power supply voltage and ground) to the semiconductor die  102 . As shown in  FIG.  4 B , the electrical connections between the contact pads  132  and the semiconductor die  102  can be facilitated by connections  133  through the package substrate  120 . The connections  133  can represent electrical paths formed through the package substrate  120 , such as connections associated with vias and conductors of a multilayer laminated package substrate. 
     The packaged RF module  100  also includes the molding compound or encapsulation structure  140  formed over the packaging substrate  120  and the components and die(s) disposed thereon. 
     It will be understood that although the packaged RF module  100  is described in the context of electrical connections based on wirebonds, one or more features of the present disclosure can also be implemented in other packaging configurations, including, for example, flip-chip configurations. 
     With continuing reference to  FIGS.  4 A and  4 B , the packaged RF module  100  further includes the electromagnetic shielding structure  150 , which includes an outer layer  151  that includes cobalt. In this embodiment, the outer cobalt layer  151  does not extend along the sides  152  of the electromagnetic shielding structure  150 . However, other implementations are possible. In certain implementations, the sides  152  includes a plurality of wire bonds that operate to fence or cage a perimeter of the semiconductor die  102 . 
       FIG.  5    is a cross-section of another embodiment of a packaged RF module  250 . 
     As illustrated in  FIG.  5   , a molding material or compound  222  can be disposed over one or more RF components  212  (for instance, semiconductor dies of the same or different processing technology), and the wire bonds  218 . In  FIG.  5   , upper portions  223  of wire bonds  218  can extend above upper surface  224  of an overmold structure of the molding material  222  that is over the wire bonds  218 . Thus, the wire bonds  218  can be exposed by removing molding material after forming an overmold structure of the molding material  222 . Having the upper portions  223  of the wire bonds  218  exposed as shown in  FIG.  5    can allow a conductive structure  232  over the molding material  222  to be in contact with the wire bonds  218  to thereby provide an electrical connection. 
     As shown in  FIG.  5   , the conductive structure  232  includes an outer layer  236 . The conductive structure  232  operates in combination with the wire bonds  218  as an electromagnetic shielding structure to the RF components  212 . 
     With continuing reference to  FIG.  5   , vias  226  are included in the package substrate  216 . The wire bonds  218  can be electrically connected to a ground plane  227  of the package substrate  216  by way of the vias  226 . The wire bonds  218  can be electrically connected to a ground contact of a system board on which the module  250  is disposed by way of the vias  226 . 
     Accordingly, in certain implementations herein, an electromagnetic shielding structure including an outer cobalt layer is grounded. 
       FIG.  6    is a front perspective view of one embodiment of another embodiment of a phone board  300 . The phone board  300  includes a packaged RF component  301  and a wireless charging circuit  304  thereon. 
     The packaged RF component  301  includes an RF component  302  and an electromagnetic shielding structure  303  at least partially enclosing the RF component  302 . The electromagnetic shielding structure  303  includes an outer cobalt layer over at least a portion of the electromagnetic shielding structure  303 . 
     By including the outer cobalt layer, the RF component  302  is shielded from electromagnetic emissions of the wireless charging circuit  304 . 
       FIG.  7    is a plan view of another embodiment of a packaged RF component  400 . The packaged RF component includes an electromagnetic shielding structure including an outer cobalt layer. 
       FIG.  8    is a plan view of another embodiment of a phone board  500 . The phone board  500  includes a first packaged RF component  501 , a second packaged RF component  502 , a third packaged RF component  503 , and a fourth packaged RF component  504  thereon. 
     The first and second packaged RF components  501 ,  502  include an electromagnetic shielding structure including an outer cobalt layer. In contrast, the third and fourth packaged RF components  503 ,  504  omit an outer cobalt layer. 
     As shown in  FIG.  8   , including cobalt in the outer layer also can provide the packaged RF components  501 ,  502  with a blue color. The blue color can provide a number of benefits. For example, in certain implementations, high performance parts, such as those complying with a particular communication standard (for instance, 5G), are implemented with an electromagnetic shielding having an outer layer of cobalt for enhanced performance. 
     Such blue color RF components and modules can be easily identified by sight, not only during manufacture, assembly, and/or test, but also after inclusion in an RF communication device (for instance, on a circuit board). For example, the blue color can provide contrast, to black, grey, and/or silver components (for instance, packaged RF components  503 ,  504 ) typically associated with electronics. 
     Moreover, when assembling certain RF communication devices, such as mobile phones, multiple RF components or modules can be placed on a tape, which in turn can be placed on a reel. The blue color can readily distinguish a tape and reel including components or modules shielded with an outer cobalt layer from the tape and reel of other RF components or modules, thereby reducing operator error. 
       FIG.  9    is a schematic diagram of one embodiment of a mobile device  800 . The mobile device  800  includes a baseband system  801 , a transceiver  802 , a front end system  803 , antennas  804 , a power management system  805 , a memory  806 , a user interface  807 , and a battery  808 . 
     The mobile device  800  can be used communicate using a wide variety of communications technologies, including, but not limited to, 2G, 3G, 4G (including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (for instance, Wi-Fi), WPAN (for instance, Bluetooth and ZigBee), WMAN (for instance, WiMax), and/or GPS technologies. 
     The transceiver  802  generates RF signals for transmission and processes incoming RF signals received from the antennas  804 . It will be understood that various functionalities associated with the transmission and receiving of RF signals can be achieved by one or more components that are collectively represented in  FIG.  9    as the transceiver  802 . In one example, separate components (for instance, separate circuits or dies) can be provided for handling certain types of RF signals. 
     The front end system  803  aids is conditioning signals transmitted to and/or received from the antennas  804 . In the illustrated embodiment, the front end system  803  includes one or more packaged RF components and/or modules  809  implemented in accordance with the teachings herein. The one or more packaged RF components/modules  809  can include one or more power amplifiers (PAs)  811 , one or more low noise amplifiers (LNAs)  812 , one or more filters  813 , one or more RF switches  814 , one or more duplexers  815 , and/or other circuitry fabricated thereon. Although various examples of RF circuitry for packaged RF components/modules has been described, other implementations are possible. 
     For example, the front end system  803  can provide a number of functionalities, including, but not limited to, amplifying signals for transmission, amplifying received signals, filtering signals, switching between different bands, switching between different power modes, switching between transmission and receiving modes, duplexing of signals, multiplexing of signals (for instance, diplexing or triplexing), or some combination thereof. 
     In certain implementations, the mobile device  800  supports carrier aggregation, thereby providing flexibility to increase peak data rates. Carrier aggregation can be used for both Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD), and may be used to aggregate a plurality of carriers or channels. Carrier aggregation includes contiguous aggregation, in which contiguous carriers within the same operating frequency band are aggregated. Carrier aggregation can also be non-contiguous, and can include carriers separated in frequency within a common band or in different bands. 
     The antennas  804  can include antennas used for a wide variety of types of communications. For example, the antennas  804  can include antennas for transmitting and/or receiving signals associated with a wide variety of frequencies and communications standards. 
     In certain implementations, the antennas  804  support MIMO communications and/or switched diversity communications. For example, MIMO communications use multiple antennas for communicating multiple data streams over a single radio frequency channel. MIMO communications benefit from higher signal to noise ratio, improved coding, and/or reduced signal interference due to spatial multiplexing differences of the radio environment. Switched diversity refers to communications in which a particular antenna is selected for operation at a particular time. For example, a switch can be used to select a particular antenna from a group of antennas based on a variety of factors, such as an observed bit error rate and/or a signal strength indicator. 
     The mobile device  800  can operate with beamforming in certain implementations. For example, the front end system  803  can include phase shifters having variable phase controlled by the transceiver  802 . Additionally, the phase shifters are controlled to provide beam formation and directivity for transmission and/or reception of signals using the antennas  804 . For example, in the context of signal transmission, the phases of the transmit signals provided to the antennas  804  are controlled such that radiated signals from the antennas  804  combine using constructive and destructive interference to generate an aggregate transmit signal exhibiting beam-like qualities with more signal strength propagating in a given direction. In the context of signal reception, the phases are controlled such that more signal energy is received when the signal is arriving to the antennas  804  from a particular direction. In certain implementations, the antennas  804  include one or more arrays of antenna elements to enhance beamforming. 
     The baseband system  801  is coupled to the user interface  807  to facilitate processing of various user input and output (I/O), such as voice and data. The baseband system  801  provides the transceiver  802  with digital representations of transmit signals, which the transceiver  802  processes to generate RF signals for transmission. The baseband system  801  also processes digital representations of received signals provided by the transceiver  802 . As shown in  FIG.  9   , the baseband system  801  is coupled to the memory  806  to facilitate operation of the mobile device  800 . 
     The memory  806  can be used for a wide variety of purposes, such as storing data and/or instructions to facilitate the operation of the mobile device  800  and/or to provide storage of user information. 
     The power management system  805  provides a number of power management functions of the mobile device  800 . In the illustrated embodiment, the power management circuit  805  include a wireless charging circuit  819 , which is operable to charge the battery  808  in response to an electromagnetic field from a charging station (not shown in  FIG.  9   ). 
     In certain implementations, at least one of the packaged RF components/modules  809  includes an outer layer including cobalt. Additionally, the outer layer is configured to shield the radio frequency circuits therein from electromagnetic emissions of the wireless charging circuit  819 . 
     By implementing one or more of the packaged RF components/modules  809  with an outer layer that includes cobalt, wideband shielding of the RF circuitry can be achieved. For example, electromagnetic shielding can be provided at frequencies associated with emissions of the wireless charging circuit  819 , including, but not limited to, frequencies in the range of about 100 Khz to about 5 MHz. Thus, the mobile device  800  is able to communicate even when cradled in a wireless charging circuit. 
     In certain implementations, the power management system  805  includes a PA supply control circuit that controls the supply voltages of the power amplifiers  811 . For example, the power management system  805  can be configured to change the supply voltage(s) provided to one or more of the power amplifiers  811  to improve efficiency, such as power added efficiency (PAE). 
     As shown in  FIG.  9   , the power management system  805  receives a battery voltage from the battery  808 . The battery  808  can be any suitable battery for use in the mobile device  800 , including, for example, a lithium-ion battery. 
     Applications 
     Some of the embodiments described above have provided examples in connection with mobile devices. However, the principles and advantages of the embodiments can be used for any other systems or apparatus that have needs for packaged RF components and modules including an electromagnetic shielding structure having an outer cobalt layer. Examples of such RF communication systems include, but are not limited to, mobile phones, tablets, base stations, network access points, customer-premises equipment (CPE), laptops, and wearable electronics. 
     CONCLUSION 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list. 
     Moreover, conditional language used herein, such as, among others, “can,” “could,” “might,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. 
     The above detailed description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative embodiments may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or may be performed at different times. 
     The teachings of the invention provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments. 
     While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.