Patent Publication Number: US-8987061-B2

Title: Methods for antenna switch modules

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 13/570,077, filed Aug. 8, 2012 and titled “ANTENNA SWITCH MODULES AND METHODS OF MAKING THE SAME”, which claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/522,065, filed Aug. 10, 2011 and titled “ANTENNA SWITCH MODULES AND METHODS OF MAKING THE SAME”, each of which are herein incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments of the invention relate to electronic systems, and in particular, to radio frequency (RF) electronics. 
     2. Description of the Related Technology 
     An RF system can include an antenna for receiving and/or transmitting RF signals. However, there can be several components in an RF system that may need to access to the antenna. For example, an RF system can include different transmit or receive paths associated with different frequency bands, different communication standards and/or different power modes, and each path may need access to the antenna at certain instances of time. 
     An antenna switch module can be used to electrically connect an antenna to a particular transmit or receive path of the RF system, thereby allowing multiple components to access the antenna. The performance of the antenna switch module can be important, since the antenna switch module can introduce noise and/or insertion loss. Furthermore, the antenna switch module can impact the area of the RF system, thereby affecting a form factor of a wireless device using the antenna switch module. 
     There is a need for an antenna switch module having a relatively small area. Furthermore, there is a need for an antenna switch module that has a relatively low insertion loss, improved harmonic performance, and a relatively high degree of isolation. 
     SUMMARY 
     In certain embodiments, the present disclosure relates to an antenna switch module including a package substrate implemented to receive one or more electrical components, a silicon on insulator (SOI) die, and a first integrated filter. The SOI die includes a first capacitor and a switch configured to be coupled to a plurality of radio frequency (RF) signal paths. The SOI die is attached to the package substrate. The first integrated filter is configured to filter an RF signal received on a first RF signal path of the plurality of RF signal paths, and the first integrated filter includes the first capacitor of the SOI die and a first inductor. 
     In several embodiments, the package substrate includes a plurality of conductive layers and a plurality of non conductive layers. According to certain embodiments, the first inductor is formed at least partly from a first conductive layer of the plurality of conductive layers, the first conductive layer disposed beneath a layer of the package substrate used to attach the SOI die. In a number of embodiments, the first inductor is a spiral inductor formed from trace of the first conductive layer. According to some embodiments, the first inductor is formed from trace of more than one of the plurality of conductive layers. 
     In several embodiments, the first inductor has an inductance ranging between about 2.5 nH and about 7 nH. According to some embodiments, the first capacitor has a capacitance ranging between about 0.8 pF and about 2.7 pF. 
     In certain embodiments, the first inductor is a surface mount component attached to the package substrate adjacent the SOI die. 
     In a number of embodiments, the antenna switch module further includes a second integrated filter configured to filter a RF signal received on a second RF signal path of the plurality of RF signal paths. The second integrated filter including a second capacitor of the SOI die and a second inductor. In certain embodiments, the package substrate includes a plurality of conductive layers and a plurality of non conductive layers, and the first and second inductors are formed at least partly from a first conductive layer of the plurality of conductive layers, the first conductive layer disposed beneath a layer of the package substrate used to attach the SOI die. In a number of embodiments, the first and second inductors are separated by a column of vias in the package substrate. In some other embodiments, the first inductor includes a surface mount inductor attached to the package substrate adjacent the SOI die and the second inductor is formed at least partly from a first conductive layer of a plurality of conductive layers of the package substrate, the first conductive layer disposed beneath a layer of the package substrate used to attach the SOI die. In certain other embodiments, the first and second inductors include first and second surface mount inductors, respectively, the first and second surface mount inductors attached to the package substrate. 
     In various embodiments, the SOI die is electrically connected to the package substrate using bond wires. 
     In accordance with a number of embodiments, the SOI die is a flip-chip die that is electrically connected to the package substrate using solder bumps. 
     In several embodiments, the first inductor and first capacitor are electrically connected in series. 
     In some embodiments, the switch is a single pole multi-throw switch. 
     In certain embodiments, the present disclosure relates to a package substrate implemented to receive one or more electrical components, a SOI die including a capacitor and a switch configured to be coupled to a plurality of radio frequency (RF) signal paths, and a means for filtering an RF signal received on a first RF signal path of the plurality of RF signal paths. The SOI die is attached to the package substrate. The filtering means includes the capacitor of the SOI die and an inductor associated with the package substrate. 
     In several embodiments, the package substrate includes a plurality of conductive layers and a plurality of non conductive layers. In a number of embodiments, the inductor is formed at least partly from a first conductive layer of the plurality of conductive layers, the first conductive layer disposed beneath a layer of the package substrate used to attach the SOI die. 
     In some embodiments, the inductor is a surface mount component attached to the package substrate adjacent the SOI die. 
     In certain embodiments, the present disclosure relates to a method of making an antenna switch module. The method includes providing a package substrate implemented to receive one or more electrical components, attaching a SOI die to the package substrate, and providing an integrated filter. The SOI die includes a capacitor and a switch configured to be coupled to a plurality of radio frequency (RF) signal paths. The integrated filter is configured to filter an RF signal received on a first RF signal path of the plurality of RF signal paths. The integrated filter includes the capacitor of the SOI die and an inductor. 
     In a number of embodiments, the method further includes forming the inductor at least partly from a first conductive layer of a plurality of conductive layers of the package substrate, the first conductive layer disposed beneath a layer of the package substrate used to attach the SOI die. 
     In various embodiments, the inductor is a surface mount component, and the method further includes attaching the inductor to the package substrate adjacent the SOI die. 
     In certain embodiments, the present disclosure relates to a wireless device including an antenna switch module. The antenna switch module includes a package substrate, a SOI die, and an integrated filter. The SOI die includes a capacitor and a switch electrically connected to a plurality of radio frequency (RF) signal paths. The SOI die is attached to the package substrate. The integrated filter includes the capacitor of the SOI die and an inductor. The integrated filter is configured to filter an RF signal received on a first RF signal path of the plurality of RF signal paths. 
     In some embodiments, the package substrate includes a plurality of conductive layers and a plurality of non conductive layers. In a number of embodiments, the inductor is formed at least partly from a first conductive layer of the plurality of conductive layers, the first conductive layer disposed beneath a layer of the package substrate used to attach the SOI die. 
     In various embodiments, the inductor is a surface mount component attached to the package substrate adjacent the SOI die. 
     According to some embodiments, the wireless device further includes an antenna electrically connected to the antenna switch module. 
     In certain embodiments, the wireless device further includes a transceiver electrically connected to the antenna switch module. 
     In several embodiments, the wireless device further includes a Wi-Fi module electrically connected to the antenna switch module. 
     In various embodiments, the wireless device further includes a mobile television module electrically connected to the antenna switch module. 
     In some embodiments, the wireless device further includes a front end module electrically connected to the antenna switch module. 
     In certain embodiments, the wireless device further includes a power amplifier module electrically connected to the antenna switch module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of one example of a wireless device that can include one or more antenna switch modules. 
         FIG. 2  is a schematic block diagram of another example of a wireless device that can include one or more antenna switch modules. 
         FIG. 3  is a schematic block diagram of one example of an antenna switch module. 
         FIG. 4A  is a schematic top plan view of an antenna switch module according to one embodiment. 
         FIG. 4B  is a cross section of the antenna switch module of  FIG. 4A  taken along the lines  4 B- 4 B. 
         FIG. 4C  is a schematic top plan view of one example of a conductive layer for a package substrate of the antenna switch module of  FIGS. 4A-4B . 
         FIG. 5A  is a schematic top plan view of an antenna switch module according to another embodiment. 
         FIG. 5B  is a schematic top plan view of one example of a conductive layer for a package substrate of the antenna switch module of  FIG. 5A . 
         FIG. 6  is a schematic top plan view of an antenna switch module according to another embodiment. 
         FIG. 7A  is a cross section of an antenna switch module according to another embodiment. 
         FIG. 7B  is a schematic top plan view of one example of a conductive layer for a package substrate of the antenna switch module of  FIG. 7A . 
         FIGS. 8A-8C  are cross sections of various examples of via structures for antenna switch modules. 
         FIG. 9  is a circuit diagram illustrating one example of a filter. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the claimed invention. 
     Antenna switch modules and methods of making the same are disclosed herein. In certain implementations, an antenna switch module is provided for selecting a particular RF transmit or receive path. The antenna switch module includes a package substrate, an integrated filter, and a silicon on insulator (SOI) die attached to the package substrate. The SOI die includes a capacitor configured to operate in the integrated filter and a multi-throw switch for selecting amongst the RF signal paths. In some implementations, a surface mount inductor is attached to the package substrate adjacent the SOI die and is configured to operate in the integrated filter with the capacitor. In certain implementations, the inductor is formed from a conductive layer of the package substrate disposed beneath a layer of the package substrate used to attach the SOI die. By providing the antenna switch module with an integrated filter that includes the capacitor of the SOI die, the area of the antenna switch module can be reduced relative to a scheme in which the capacitor is formed in other ways, such as using surface mount components. Additionally, the antenna switch modules described herein can have low insertion loss and/or high isolation. In some implementations, the antenna switch module includes a plurality of integrated filters and the SOI die includes a plurality of capacitors configured to operate in the integrated filters. 
     Overview of Examples of Wireless Devices that can Include Antenna Switch Modules 
       FIG. 1  is a schematic block diagram of one example of a wireless or mobile device  11  that can include one or more antenna switch modules. The wireless device  11  can include antenna switch modules implementing one or more features of the present disclosure. 
     The example wireless device  11  depicted in  FIG. 1  can represent a multi-band and/or multi-mode device such as a multi-band/multi-mode mobile phone. By way of examples, Global System for Mobile (GSM) communication standard is a mode of digital cellular communication that is utilized in many parts of the world. GSM mode mobile phones can operate at one or more of four frequency bands: 850 MHz (approximately 824-849 MHz for Tx, 869-894 MHz for Rx), 900 MHz (approximately 880-915 MHz for Tx, 925-960 MHz for Rx), 1800 MHz (approximately 1710-1785 MHz for Tx, 1805-1880 MHz for Rx), and 1900 MHz (approximately 1850-1910 MHz for Tx, 1930-1990 MHz for Rx). Variations and/or regional/national implementations of the GSM bands are also utilized in different parts of the world. 
     Code division multiple access (CDMA) is another standard that can be implemented in mobile phone devices. In certain implementations, CDMA devices can operate in one or more of 800 MHz, 900 MHz, 1800 MHz and 1900 MHz bands, while certain W-CDMA and Long Term Evolution (LTE) devices can operate over, for example, about 22 radio frequency spectrum bands. 
     Antenna switch modules of the present disclosure can be used within a mobile device implementing the foregoing example modes and/or bands, and in other communication standards. For example, 3G, 4G, LTE, and Advanced LTE are non-limiting examples of such standards. 
     In certain embodiments, the wireless device  11  can include an antenna switch module  12 , a transceiver  13 , an antenna  14 , power amplifiers  17 , a control component  18 , a computer readable medium  19 , a processor  20 , and a battery  21 . 
     The transceiver  13  can generate RF signals for transmission via the antenna  14 . Furthermore, the transceiver  13  can receive incoming RF signals from the antenna  14 . It will be understood that various functionalities associated with transmitting and receiving of RF signals can be achieved by one or more components that are collectively represented in  FIG. 1  as the transceiver  13 . For example, a single component can be configured to provide both transmitting and receiving functionalities. In another example, transmitting and receiving functionalities can be provided by separate components. 
     In  FIG. 1 , one or more output signals from the transceiver  13  are depicted as being provided to the antenna  14  via one or more transmission paths  15 . In the example shown, different transmission paths  15  can represent output paths associated with different bands and/or different power outputs. For instance, the two different paths shown can represent paths associated with different power outputs (e.g., low power output and high power output), and/or paths associated with different bands. The transmit paths  15  can include one or more power amplifiers  17  to aid in boosting a RF signal having a relatively low power to a higher power suitable for transmission. Although  FIG. 1  illustrates a configuration using two transmission paths  15 , the wireless device  11  can be adapted to include more or fewer transmission paths  15 . 
     In  FIG. 1 , one or more detected signals from the antenna  14  are depicted as being provided to the transceiver  13  via one or more receiving paths  16 . In the example shown, different receiving paths  16  can represent paths associated with different bands. For example, the four example paths  16  shown can represent quad-band capability that some wireless devices are provided with. Although  FIG. 1  illustrates a configuration using four receiving paths  16 , the wireless device  11  can be adapted to include more or fewer receiving paths  16 . 
     To facilitate switching between receive and/or transmit paths, the antenna switch module  12  can be included and can be used electrically connect the antenna  14  to a selected transmit or receive path. Thus, the antenna switch module  12  can provide a number of switching functionalities associated with an operation of the wireless device  11 . The antenna switch module  12  can include a multi-throw switch configured to provide functionalities associated with, for example, switching between different bands, switching between different power modes, switching between transmission and receiving modes, or some combination thereof. The antenna switch module  12  can also be configured to provide additional functionality, including filtering and/or duplexing of signals. 
       FIG. 1  illustrates that in certain embodiments, the control component  18  can be provided for controlling various control functionalities associated with operations of the antenna switch module  12  and/or other operating component(s). For example, the control component  18  can aid in providing control signals to the antenna switch module  12  so as to select a particular transmit or receive path. Non-limiting examples of the control component  18  are described herein in greater detail. 
     In certain embodiments, the processor  20  can be configured to facilitate implementation of various processes on the wireless device  11 . The processor  20  can be a general purpose computer, special purpose computer, or other programmable data processing apparatus. In certain implementations, the wireless device  11  can include a computer-readable memory  19 , which can include computer program instructions that may be provided to and executed by the processor  20 . 
     The battery  21  can be any suitable battery for use in the wireless device  11 , including, for example, a lithium-ion battery. 
       FIG. 2  is a schematic block diagram of another example of a wireless device  30  that can include one or more antenna switch modules. The illustrated wireless device  30  includes first to fifth antennas  14   a - 14   e , a power amplifier module  31 , a front-end module  32 , a diversity front-end module  34 , first to fifth antenna switch modules  40   a - 40   e , a multimode transceiver  44 , a Wi-Fi/Bluetooth module  46 , and a FM/Mobile TV module  48 . 
     The multimode transceiver  44  is electrically coupled to the power amplifier module  31 , to the front-end module  32 , and to the diversity front-end module  34 . The multimode transceiver  44  can be used to generate and process RF signals using a variety of communication standards, including, for example, Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), wideband CDMA (W-CDMA), Enhanced Data Rates for GSM Evolution (EDGE), and/or other proprietary and non-proprietary communications standards. 
     The power amplifier module  31  can include one or more power amplifiers, which be used to boost the power of RF signals having a relatively low power. Thereafter, the boosted RF signals can be used to drive the first antenna  14   a . The power amplifier module  31  can include power amplifiers associated with different power outputs (e.g., low power output and high power output) and/or amplifications associated with different bands. 
     The front-end module  32  can include circuitry that can aid the multimode transceiver  44  in transmitting and receiving RF signals. For example, the front-end module  32  can include one or more low noise amplifiers (LNAs) for amplifying signals received using the first antenna  14   a . The front-end module  32  can additionally and/or alternatively include filter circuitry, input and output matching circuitry and/or power detection circuitry. In certain implementations, the front-end module  32  can also include one or more power amplifiers. 
     The first antenna switch module  40   a  is electrically coupled to the first antenna  14   a , to the power amplifier module  31 , and to the front-end module  32 . The first antenna switch module  40   a  can be used to electrically connect the first antenna  14   a  to a desired transmit or receive path. In certain embodiments described herein, the antenna switch module  40   a  can have a relatively small area, thereby improving the form factor of a mobile device used to communicate over a cellular or other network. The antenna switch module  40   a  can also have a low insertion loss and high band-to-band isolation, which can improve the quality of signals transmitted or received. For example, the antenna switch module can improve the quality of voice or data transmissions made using the first antenna  14   a  and/or improve reception quality for a given amount of power consumption. 
     In certain implementations, the diversity front-end module  34 , the second antenna switch module  40   b , and the second or diversity antenna  14   b  can also be included. Using a diversity front-end module  34  and the second antenna  14   b  can help improve the quality and/or reliability of a wireless link by reducing line-of-sight losses and/or mitigating the impacts of phase shifts, time delays and/or distortions associated with signal interference of the first antenna  14   a . In some implementations, a plurality of diversity front-end modules, diversity antennas, and antenna switch modules can be provided to further improve diversity. 
     As illustrated in  FIG. 2 , the second antenna switch module  40   b  has been used to select amongst a multitude of RF signal paths associated with the diversity antenna  14   b . In certain embodiments described herein, the second antenna switch module  14   b  can have a small area and a relatively low insertion loss and noise. Accordingly, the second antenna switch module  14   b  can help improve signal quality in the diversity signal path for a given power level, thereby reducing the probability of a call drop-out or a lost connection. Furthermore, by providing an antenna switch module with a smaller area, the form factor of the wireless device  30  can be reduced. 
     The wireless device  30  includes the Wi-Fi/Bluetooth module  46 , which can be used to generate and process received Wi-Fi and/or Bluetooth signals. For example, the Wi-Fi/Bluetooth module  46  can be used to connect to a Bluetooth device, such as a wireless headset, and/or to communicate over the Internet using a wireless access point or hotspot. To aid in selecting a desired Wi-Fi or Bluetooth signal path, the third antenna switch module  14   c  has been included. In certain embodiments described herein, the antenna switch module  40   c  can have a relatively small area, thereby improving the form factor of a mobile device used to communicate over the Internet and/or with a Bluetooth accessory. The antenna switch module  40   c  can also have a low insertion loss and a high isolation, which can impact the quality of voice transmissions made or received using a Bluetooth device and/or improve the quality of a Wi-Fi Internet connection. For example, the antenna switch module  40   c  can improve connection strength and/or access range of the wireless device  30  to a wireless access point for a given amount of power consumption. 
     The FM/Mobile TV module  48  can be included in the wireless device  30 , and can be used to receive and/or transmit radio or television signals, such as FM signals and/or VHF signals. The FM/Mobile TV module  48  can communicate with the fourth and fifth antennas  14   d ,  14   e  using the fourth and fifth antenna switch modules  40   d ,  40   e , respectively. In certain embodiments described herein, the antenna switch modules  40   d ,  40   e  can have a relatively small area, thereby improving the form factor of a mobile device having mobile TV or FM radio capabilities. Additionally, the antenna switch modules  40   d ,  40   e  can also have a low insertion loss and high isolation, which can lead to improved streaming of multimedia content for a given amount of power consumption. 
     Although antenna switch modules have been illustrated and described above in the context of two examples of wireless devices, the antenna switch modules described herein can be used in other wireless devices and electronics. 
     Overview of Antenna Switch Modules 
       FIG. 3  is a schematic block diagram of one example of an antenna switch module  50 . The antenna switch module  50  includes a high band filter  51 , a low band filter  52 , a switch  54 , and switch control logic  56 . 
     The high band filter  51  is electrically connected to a first signal port TX1 of the antenna switch module  50  and to the switch  54 . The low band filter  52  is electrically connected to a second signal port TX2 of the antenna switch module  50  and to the switch  54 . The switch  54  is also electrically connected to an antenna port ANT of the antenna switch module  50  and to a third signal port TRX1, a fourth signal port TRX2, a fifth signal port TRX3, a sixth signal port TRX4, a seventh signal port RX1, an eighth signal port RX2, a ninth signal port RX3, and a tenth signal port RX4 of the antenna switch module  50 . Although the antenna switch module  50  is illustrated as including ten signal ports and one antenna port, in certain implementations the antenna switch module can include more or fewer signal ports and/or additional antenna ports. 
     The switch  54  can be used to electrically connect a particular RF signal path to an antenna. For example, an antenna can be electrically coupled to the antenna port ANT, and RF signal paths or components can be electrically connected to the signal ports of the antenna switch module  50 . The switch control logic  56  can be configured to control the switch  54  such that a signal port associated with a selected RF signal path is electrically connected to the antenna port ANT. In certain implementations, the switch  54  is a multi-throw switch. However, the switch  54  can be implemented in any suitable manner, and in some implementations can include a plurality of switch components configured to collective operate as a multi-throw switch. Although not illustrated, the switch control logic  56  can include inputs and/or outputs to aid the switch control logic  56  in communicating with other circuitry, including, for example, circuitry external to the antenna switch module  50 . 
     As described earlier, electrically coupling multiple RF signal paths to an antenna using the antenna switch module  50  can help an electronic device communicate over a variety of networks, use different power modes, and/or communicate using different communication standards. For example, the illustrated configuration can be used to support quad-band GSM/EDGE and/or multi-band configurations of W-CDMA or LTE. However, persons having ordinary skill in the art will appreciate that the switch control module  50  can be configured in other ways. 
     One or more of the terminals or ports of the antenna switch module  50  can be electrically coupled to a filter to aid in filtering unwanted harmonics and/or noise from an RF signal. For example, the first and second signal ports TX1, TX2 have been electrically coupled to the high band and low band filters  51 ,  52 , respectively. In certain implementations, the high band filter  51  is a low-pass filter configured to filter a GSM or CDMA signal in the 1800 MHz and/or 1900 MHz bands and the low band filter  52  is a low-pass filter configured to filter a GSM or CDMA signal in the 800 MHz and/or 900 MHz bands. However, the high band and low band filters  51 ,  52  can be implemented in other ways, and can be configured to, for example, filter signals of different standards and/or frequencies. Additionally, although only two of the signal ports of the antenna switch module  50  are illustrated as including filters, more or fewer signal ports of the antenna switch module  50  can include filters. 
       FIG. 4A  is a schematic top plan view of an antenna switch module  60  according to one embodiment. The antenna switch module  60  includes a package substrate  62 , a silicon on insulator (SOI) die  70 , and bond wires  78 . 
     The package substrate  62  includes a die attach paddle or pad  64  and bond pads  66 . The SOI die  70  has been attached or mounted to the die attach pad  64  of the package substrate  62 . Although not illustrated in  FIG. 4A , the package substrate  62  can include a plurality of conductive and non-conductive layers laminated together, and the die attach pad  64  and the bond pads  66  can be formed from a conductive layer disposed on the surface of the package substrate used to attach the SOI die  70 . 
     The SOI die  70  includes an SOI switch  72 , a first SOI capacitor  74   a , a second SOI capacitor  74   b , and pads  76 . The SOI switch  72  can be, for example, a single pole multi-throw switch, such as a SP9T switch. In certain implementations, the SOI switch  72  can include a plurality of switches or switch elements configured to collective operate as a multi-throw switch. 
     As illustrated in  FIG. 4A , bond wires  78  can be used for electrically connecting the pads  76  of the SOI die  70  to bond pads  66  disposed on the package substrate  62 . The bond wires  78  can provide power, ground, and/or signal connections between the SOI die  70  and the package substrate  62 . Although the antenna switch module  60  is illustrated as using bond wires  78  to establish electrical connections between the SOI die  70  and the package substrate  62 , the SOI die  70  can be electrically connected in other ways. For example, as will be described in detail below with reference to  FIGS. 7A-7B , the SOI die  70  can be used in a flip-chip configuration. Accordingly, the bond wires  78  need not be included in some implementations. 
     The first and second SOI capacitors  74   a ,  74   b  can be capacitors formed on the SOI die  70 , such as metal-insulator-metal (MIM) capacitors and/or metal-oxide-metal (MOM) capacitors. In one embodiment, the first and second SOI capacitors  74   a ,  74   b  each have a capacitance selected to be in the range of about 0.8 pF to about 2.7 pF. For example, the SOI capacitors can have a capacitance of about 0.8 pF for DCS/PCS high band and about 2.65 pF for GSM/EDGE low band. The first and second SOI capacitors  74   a ,  74   b  can occupy any suitable amount of die area, such as between about 29,925 square um to about 33,972 square um of die area, for example, about 32,000 square um of die area. 
     As will be described in detail below with reference to  FIGS. 4B-4C , the antenna switch module  60  includes integrated filters formed from the first and second SOI capacitors  74   a ,  74   b  and from inductors (not illustrated in  FIG. 4A ) disposed in the package substrate  62 . By including integrated filters in the antenna switch module  60 , RF signal quality can be improved by reducing or removing harmonic signal components from RF signals traveling through the antenna switch module  60 . Additionally, forming integrated filters from capacitors disposed on an SOI die  70  and from inductors disposed in the package substrate  62  can reduce the form factor of the antenna switch module  60  by using three-dimensional (3D) integrated filter structures. For example, the illustrated antenna switch module  60  can have a reduced size relative to a scheme in which spiral inductors and surface mount capacitors are disposed side by side on a surface of the package substrate adjacent a switch die. 
       FIG. 4B  is a cross section of the antenna switch module  60  of  FIG. 4A  taken along the lines  4 B- 4 B. The antenna switch module  60  includes the package substrate  62 , the SOI die  70 , and the bond wires  78 . The illustrated package substrate  62  is a multi-layer substrate including first to sixth conductive layers  81 - 86  and first to fifth non-conductive layers  91 - 95 .  FIG. 4C  is a schematic top plan view of one example of the third conductive layer  83  of the package substrate  62  of  FIGS. 4A-4B . The third conductive layer  83  includes a first spiral inductor  101 , a second spiral inductor  102  and first to eleventh vias  104   a - 104   k.    
     The package substrate  62  can include one or more inductors that can be used with SOI capacitors to form integrated filters of the antenna switch module  60 . For example, the third conductive layer  83  includes the first and second spiral inductors  101 ,  102 , which can be electrically connected to the first and second capacitors  74   a ,  74   b  (see  FIG. 4A ) of the SOI die  70  to form a high band and a low band filter, respectively. Accordingly, in certain implementations described herein, an antenna switch module is provided with at least one integrated filter that includes a capacitor disposed on an SOI die and an inductor formed from a conductive layer of a package substrate. 
     As shown in  FIG. 4B , the conductive layers  81 - 86  can be configured to alternate with the non-conductive layers  91 - 95 . For example, the first non-conductive layer  91  is disposed between the first and second conductive layers  81 ,  82 , the second non-conductive layer  92  is disposed between the second and third conductive layers  82 ,  83 , the third non-conductive layer  93  is disposed between the third and fourth conductive layers  83 ,  84 , the fourth non-conductive layer  94  is disposed between the fourth and fifth conductive layers  84 ,  85 , and the fifth non-conductive layer  95  is disposed between the fifth and sixth conductive layers  85 ,  86 . Although the illustrated package substrate  62  includes six conductive layers and five non-conductive layers, more or fewer conductive and/or non-conductive layers can be provided. Additionally, although the package substrate  62  is shown as including conductive layers on the major surfaces of the package substrate  62 , non-conductive layers can be included instead on one or more of the major surfaces of the package substrate  62 . 
     The first to sixth conductive layers  81 - 86  can each be been patterned to form traces. For example, the first conductive layer  81  has been patterned to form the bond pads  66  and the die attach pad  64 , which has been used to attach the SOI die  70 . Additionally, the third conductive layer  83  has been patterned to form the first and second spiral inductors  101 ,  102 , which can be formed from trace of the third conductive layer  83 . Although the first and second spiral inductors  101 ,  102  are illustrated as being formed from the third conductive layer  83  of the package substrate  62 , the first and second spiral inductors  101 ,  102  can be formed from any suitable layer of the package substrate  62 , including, for example, any conductive layer of the package substrate disposed beneath the layer used to attach the SOI die  70 . In some implementations, the first and second spiral inductors  101 ,  102  can be formed from trace of more than one conductive layer of the package substrate  62 . For example, in one embodiment, the first and second inductors  101 ,  102  are each formed from spiral inductor structures disposed on the third and fourth conductive layers  83 ,  84 . 
     Vias can be formed between conductive layers to allow electrical connections to be made within the package substrate  62 . For example, openings or holes can be provided in any of the non-conductive layers  91 - 95  of the package substrate  62  and the holes can be filled with a conductor to form vias in the package substrate  62  for electrically connecting adjacent conductive layers. Accordingly, an electrical circuit can be formed by selecting the pattern of the conductive layers  81 - 86  and by selecting the location of the vias. The package substrate  62  can be any suitable multi-layer substrate, such as a multi-chip-module (MCM) substrate including alternating conductive and nonconductive layers. In one implementation, the conductive layers comprise copper and the nonconductive layers comprise a prepreg material. Although a particular configuration of vias is illustrated in  FIG. 4C , more or fewer vias can be included. For example, additional vias associated with ground or power connections can be provided. 
     The first and second spiral inductors  101 ,  102  can be electrically connected to the first and second capacitors  74   a ,  74   b  (see  FIG. 4A ) of the SOI die  70  to form integrated filters. For example, the first and second spiral inductors  101 ,  102  can be electrically connected to the first and second capacitors  74   a ,  74   b , respectively, by using via structures in the package substrate  62  and by using the bond wires  78 . In one implementation, the first inductor  101  has an inductance in the range of about 6 nH to about 7 nH, for example, about 6.5 nH, and the second inductor  102  has an inductance in the range of about 2.5 nH to about 3 nH, for example, about 2.8 nH. Persons having ordinary skill in the art will appreciate that the first and second spiral inductors  101 ,  102  illustrate one of many examples of spiral inductor structures suitable for use with the antenna switch module  60 . 
     To aid in electrically isolating the first and second inductors  101 ,  102  from each other, a column of vias can be provided between the first and second inductors  101 ,  102 . For example, as shown in  FIG. 4C , the first to seventh vias  104   a - 104   g  have been provided between the first and second inductors  101 ,  102  to help prevent magnetic and/or electric fields of the inductors from interfering with one another. In certain implementations, vias can be placed between each conductive layer such that each of the vias in the column extends from a first major surface of the package substrate to a second major surface of the package substrate. Although seven vias are illustrated as being used to electrically isolate the first and second inductors  101 ,  102 , more or fewer vias can be used. For example, between about 6 vias and about 9 vias can be disposed in a column between the first and second inductors  101 ,  102 . However, more or fewer vias can be used in certain configurations. In one implementation, adjacent vias in the column of vias are separated by a distance of less than about 230 um. Various examples of vias structures suitable for use in electrically isolating the first and second inductors  101 ,  102  will be described in further detail below with reference to  FIGS. 8A-8C . 
     Although the antenna switch module  60  of  FIGS. 4A-4C  is illustrated and described as including two integrated filters, the antenna switch module  60  can be configured to include more or fewer integrated filters. 
       FIG. 5A  is a schematic top plan view of an antenna switch module  110  according to another embodiment. The antenna switch module  110  includes the package substrate  62 , the SOI die  70 , the bond wires  78 , and a surface mount inductor  102 . The package substrate  62  includes the die attach pad  64  and the bond pads  66 , and the SOI die  70  includes the SOI switch  72 , the first capacitor  74   a , the second capacitor  74   b , and the pads  76 . The SOI die  70  has been mounted or attached to the die attach pad  64 , and the bond wires  78  have been used to attach the pads  76  of the SOI die  70  to the bond pads  66 . The surface mount inductor  102  is mounted or attached to the package substrate  62  adjacent the SOI die  70 . The surface mount inductor  102  is electrically connected to the second capacitor  74   b  of the SOI die  70 . 
     As was described earlier with respect to  FIG. 4B , the package substrate  62  can be a multi-layer substrate including a plurality of conductive and non-conductive layers.  FIG. 5B  is a schematic top plan view of one example of a conductive layer  120  for the package substrate  62  of  FIG. 5A . The conductive layer  120  includes a spiral inductor  121  and first and second vias  124   a ,  124   b , which can aid in electrically connecting the spiral inductor  121  to the first capacitor  74   a  of the SOI die  70 . 
     The antenna switch module  110  of  FIG. 5A  is similar to the antenna switch module  60  of  FIGS. 4A-4B , except that the antenna switch module  110  includes integrated filters configured in a different arrangement. For example, the antenna switch module  110  includes a first integrated filter formed using the first SOI capacitor  74   a  and the spiral inductor  121  of the package substrate  62 . Additionally, the antenna switch module  110  further includes a second integrated filter formed using the second SOI capacitor  74   b  and the surface mount inductor  102 . In one embodiment, the first integrated filter is a high band filter and the second integrated filter is a low band filter. 
     In certain implementations described herein, an antenna switch module can include integrated filters formed from SOI capacitors and surface mount inductors and/or formed from SOI capacitors and spiral inductors of a package substrate. Using both surface mount inductors and spiral inductors formed from package substrate trace can aid in improving isolation between filters. Additionally, using both surface mount inductors and spiral inductors in integrated filter structures can increase routing resources in the package substrate, thereby allowing traces and vias to be used for other purposes, such as increasing a robustness of a ground supply provided to the SOI die through the package substrate. 
       FIG. 6  is a schematic top plan view of an antenna switch module  140  according to another embodiment. The antenna switch module  140  includes the package substrate  62 , an SOI die  150 , the bond wires  78 , and first and second surface mount inductors  102   a ,  102   b . The package substrate  62  includes the die attach pad  64  and the bond pads  66 , and the SOI die  150  includes the SOI switch  72 , the first capacitor  74   a , the second capacitor  74   b , and the pads  76 . The SOI die  150  has been mounted or attached to the die attach pad  64 , and the bond wires  78  have been used to attach the pads  76  of the SOI die  150  to the bond pads  66 . The first and second surface mount inductors  102   a ,  102   b  are mounted or attached to the package substrate  62  adjacent the SOI die  150 , and the first and second surface mount inductors  102   a ,  102   b  are electrically connected to the first and second capacitors  74   a ,  74   b , respectively. 
     The antenna switch module  140  of  FIG. 6  is similar to the antenna switch module  60  of  FIGS. 4A-4C , except that the antenna switch module  140  includes integrated filters configured in a different arrangement. For example, the antenna switch module  140  includes a first integrated filter formed using the first SOI capacitor  74   a  and the first surface mount inductor  102   a  and a second integrated filter formed using the second SOI capacitor  74   b  and the second surface mount inductor  102   b . In certain implementations described herein, an antenna switch module can include integrated filters formed from SOI capacitors and surface mount inductors. Additional details of the antenna switch module  140  can be similar to those of the antenna switch module  60  described earlier. 
       FIG. 7A  is a cross section of an antenna switch module  160  according to another embodiment. The antenna switch module  160  includes a package substrate  164 , a SOI die  170  and solder bumps or balls  162 . The package substrate  164  includes first to sixth conductive layers  171 - 176  and first to fifth non-conductive layers  181 - 185 .  FIG. 7B  is a schematic top plan view of one example of the fourth conductive layer  174  of the package substrate  164  of the antenna switch module  160  of  FIG. 7A . The fourth conductive layer  174  includes a first spiral inductor  191 , a second spiral inductor  192  and first to eleventh vias  194   a - 194   k . The first to seventh vias  194   a - 194   g  have been provided as a column of vias between the first and second spiral inductors  191 ,  192  in a manner similar to that described earlier with respect to  FIG. 4C . 
     The antenna switch module  160  of  FIG. 7A  is similar to the antenna switch module  60  of  FIGS. 4A-4B , except that the antenna switch module  160  is implemented using a flip-chip configuration. For example, rather than using wire bonds to electrically connect the SOI die  170  to the package substrate  164 , the SOI die  170  of  FIG. 7A  has been flipped upside down and attached to the package substrate  164  using solder bumps  162 . The SOI die  170  can include first and second SOI capacitors, which can be electrically connected to the first and second spiral inductors  191 ,  192 , respectively, to form first and second integrated filters of the antenna switch module  160 . Accordingly, in certain implementations described herein, antenna switch modules are provided using an SOI die in a flip-chip arrangement. 
     Persons having ordinary skill in the art will appreciate that the first and second spiral inductors  191 ,  192  illustrate one of many examples of spiral inductor structures suitable for use with the antenna switch module  160 . Additionally, the first and/or second spiral inductors  191 ,  192  can be formed on any suitable conductive layer or layers of the package substrate  164 , and thus need not be formed from the fourth conductive layer  174 . Furthermore, in certain configurations, the antenna switch module  160  can be modified such that the spiral inductors  191 ,  192  are omitted in favor of using surface mount inductors or such that a mix of spiral inductors and surface mount inductors are used to form integrated filters. Additional details of the antenna switch module  160  can be similar to those described earlier with respect to the antenna switch modules of  FIGS. 4A-6 . 
       FIGS. 8A-8C  are cross sections of various examples of via structures for antenna switch modules. 
       FIG. 8A  is a cross section of one example of a portion of a package substrate  200  for an antenna switch module. The package substrate  200  includes a via structure  203  formed through a non-conductive region or structure  204  of the package substrate  200 . The via structure  203  electrically connects a first conductive layer  201  to a second conductive layer  202 , which are disposed on opposing major surfaces of the package substrate  200 . Accordingly, the via structure  203  is a through-substrate via. The via structure  203  can be used in the column of vias  104   a - 104   g  of  FIG. 4C  and/or in the column of vias  194   a - 194   g  of  FIG. 7B . 
       FIG. 8B  is a cross section of another example of a portion of a package substrate  210  for an antenna switch module. The package substrate  210  includes first to sixth conductive layers  211 - 216 , a non-conductive region or structure  228  and first to fifth vias  221 - 225 . The first to fifth vias  221 - 225  are aligned with one another and electrically connect the first conductive layer  211  to the sixth conductive layer  216 , which are disposed on opposing major surfaces of the package substrate  210 . In some implementations, one or more of the vias in the column of vias  104   a - 104   g  of  FIG. 4C  and/or in the column of vias  194   a - 194   g  of  FIG. 7B  can have a structure similar to that illustrated in  FIG. 8B . 
       FIG. 8C  is a cross section of another example of a portion of a package substrate  230  for an antenna switch module. The package substrate  230  includes first to sixth conductive layers  211 - 216 , a non-conductive region  228  and first to fifth vias  221 - 225 . The package substrate  230  is similar to the package substrate  210  of  FIG. 8B , except that the first to fifth vias  221 - 225  are staggered rather than aligned. In some implementations, one or more of the vias in the column of vias  104   a - 104   g  of  FIG. 4C  and/or in the column of vias  194   a - 194   g  of  FIG. 7B  can have a structure similar to that illustrated in  FIG. 8C . 
       FIG. 9  is a circuit diagram illustrating one example of a filter  240 . The filter  240  includes an inductor  241  and a capacitor  242 . The inductor  241  includes a first end electrically connected to a node N 1  and a second end electrically connected to a first end of the capacitor  242  at a node N 3 . The capacitor  242  further includes a second end electrically connected to a node N 2 . 
     In some implementations described herein, antenna switch modules can include an integrated filter electrically connected in the configuration shown in  FIG. 9 . For example, the filter  240  can be configured to operate as a low pass filter, and the node N 1  can be configured to receive a RF signal, the node N 2  can be electrically connected to ground, and the node N 3  can be configured to generate an output of the filter  240 . In certain implementations, an SOI capacitor operate as the capacitor  242  and a surface mount inductor and/or a spiral inductor formed from trace in a package substrate can operate as the inductor  241 . Although the filter  240  illustrates one possible implementation of the integrated filters described herein, other configurations are possible. 
     Applications 
     Some of the embodiments described above have provided examples in connection with mobile phones. However, the principles and advantages of the embodiments can be used for any other systems or apparatus that have needs for antenna switch modules. 
     Such antenna switch modules can be implemented in various electronic devices. Examples of the electronic devices can include, but are not limited to, consumer electronic products, parts of the consumer electronic products, electronic test equipment, etc. Examples of the electronic devices can also include, but are not limited to, memory chips, memory modules, circuits of optical networks or other communication networks, and disk driver circuits. The consumer electronic products can include, but are not limited to, a mobile phone, a telephone, a television, a computer monitor, a computer, a hand-held computer, a personal digital assistant (PDA), a microwave, a refrigerator, an automobile, a stereo system, a cassette recorder or player, a DVD player, a CD player, a VCR, an MP3 player, a radio, a camcorder, a camera, a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, a multi functional peripheral device, a wrist watch, a clock, etc. Further, the electronic devices can include unfinished products. 
     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,” “can,” “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.