Patent Abstract:
Embodiments contained in the disclosure provide a method and apparatus for testing an electronic device. An electronic device is installed in a test socket guide. A pusher tip applies a load to the guided coaxial spring probes and forces contact with pads on the device. Test and ground signals are routed through the device and test socket. The apparatus includes a socket having at least one guided coaxial spring probe pin. A socket guide shim is positioned between the receptacle for the electronic device and the socket. A socket guide aids positioning. A pusher tip is placed on the side opposite that of the guided coaxial spring probe pins. The pusher tip mates with a pusher shim and the pusher spring. A top is then placed on the assembly and acts to compress the pusher spring and engage the guided coaxial spring probe pins with the pads on the device.

Full Description:
FIELD 
       [0001]    The present disclosure relates generally to wireless communication systems, and more particularly to a method and apparatus for testing secure radio frequency (RF) specifications such as gain, isolation, harmonics, linearity, noise and insertion loss for test socket and probe card applications. 
       BACKGROUND 
       [0002]    Wireless communication devices have become smaller and more powerful as well as more capable. Increasingly users rely on wireless communication devices for mobile phone use as well as email and Internet access. At the same time, devices have become smaller in size. Devices such as cellular telephones, personal digital assistants (PDAs), laptop computers, and other similar devices provide reliable service with expanded coverage areas. Such devices may be referred to as mobile stations, stations, access terminals, user terminals, subscriber units, user equipments, and similar terms. 
         [0003]    A wireless communication system may support communication for multiple wireless communication devices at the same time. In use, a wireless communication device may communicate with one or more base stations by transmissions on the uplink and downlink. Base stations may be referred to as access points, Node Bs, or other similar terms. The uplink or reverse link refers to the communication link from the wireless communication device to the base station, while the downlink or forward link refers to the communication from the base station to the wireless communication devices. 
         [0004]    Wireless communication systems may be multiple access systems capable of supporting communication with multiple users by sharing the available system resources, such as bandwidth and transmit power. Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, wideband code division multiple access (WCDMA) systems, global system for mobile (GSM) communication systems, enhanced data rates for GSM evolution (EDGE) systems, and orthogonal frequency division multiple access (OFDMA) systems. 
         [0005]    All wireless devices contain electronic chips which contain modems for transmitting and receiving, and may also contain additional processing functions and memories to support the multiple modes and functions of a smart phone. All of these features must be tested before the phone is delivered to a customer. As chips or system-on-chip (SoC) devices have gained functionality, the devices have become much more complex, with multiple cores and smaller and smaller devices and pins within one SoC. Testing such SoCs has become more difficult, as probing accurately requires a very small probe. In particular, it is difficult to get accurate measurements for critical specifications such as gain, isolation, harmonics, linearity, noise, and insertion loss due to high parasitic inductance. 
         [0006]    There is a need in the art for a spring probe that adopts a guided transmission line concept which provides improved signal transition and minimum parasitic inductance at a low cost. 
       SUMMARY 
       [0007]    Embodiments contained in the disclosure provide a method of testing an electronic device. The method begins when an electronic device, such as an SoC, is installed in a test socket guide. The test socket guide forms a part of the spring pin socket and ensures proper positioning of the electronic device to be tested. A pusher tip is then installed on top of the electronic device. The pusher tip applies a load to the guided coaxial spring probes within the socket and acts to push the probes into contact with pads on the device being tested. This contact may be verified by any suitable means. Test and ground signals are then routed through the guided coaxial spring probe pins, with separate nets for signals and ground. Test results may be recorded as the test and ground signals move through the device. 
         [0008]    A further embodiment provides an apparatus for testing an electronic device. The apparatus includes a socket having at least one guided coaxial spring probe pin. Sockets may have various numbers of guided coaxial spring probe pins to allow for testing devices of varying sizes and pin/pad counts. A socket guide shim is positioned between the receptacle for the electronic device that will be tested and the socket. A socket guide ensures that the socket is correctly positioned. The electronic device is placed in the receptacle and a pusher tip is placed on the side opposite that of the guided coaxial spring probe pins. The pusher tip mates with a pusher shim and the pusher spring. A top is then placed on the assembly and acts to compress the pusher spring and engage the guided coaxial spring probe pins with the pads on the device. 
         [0009]    A still further embodiment provides an apparatus for testing an electronic device. The device includes: means for installing an electronic device to be tested into a test socket guide; means for installing a pusher tip on top of the electronic device installed in the test socket guide; means for verifying that the guided coaxial spring probes within the test socket contact pads on the electronic device; means for routing test signals and ground signals through the guided coaxial spring probe pins on the test socket; and means for recording results of the routing of test signals and ground signals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  illustrates a wireless multiple-access communication system, in accordance with certain embodiments of the disclosure. 
           [0011]      FIG. 2  is a block diagram of a wireless communication system in accordance with embodiments of the disclosure. 
           [0012]      FIG. 3  depicts multiple views of a probe interface board and probe assembly in accordance with embodiments of the disclosure. 
           [0013]      FIG. 4  illustrates use of a guided coaxial spring probe socket in accordance with embodiments of the disclosure. 
           [0014]      FIG. 5  depicts signal and ground transmission in a guided coaxial spring probe socket in accordance with embodiments of the disclosure. 
           [0015]      FIG. 6  illustrates construction of a guided coaxial spring probe socket in accordance with embodiments of the disclosure. 
           [0016]      FIG. 7  depicts each component of a guided coaxial spring probe in accordance with embodiments of the disclosure. 
           [0017]      FIG. 8  illustrates signal transmission in a guided coaxial spring probe in accordance with embodiments of the disclosure. 
           [0018]      FIG. 9  shows test results using a guided coaxial spring probe in accordance with embodiments of the disclosure. 
           [0019]      FIG. 10  is a flowchart of a method of testing high frequency applications using a guided coaxial spring probe in accordance with embodiments of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention can be practiced. The term “exemplary” used throughout this description means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary embodiments of the invention. It will be apparent to those skilled in the art that the exemplary embodiments of the invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary embodiments presented herein. 
         [0021]    As used in this application, the terms “component,” “module,” “system,” and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an integrated circuit, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network, such as the Internet, with other systems by way of the signal). 
         [0022]    Furthermore, various aspects are described herein in connection with an access terminal and/or an access point. An access terminal may refer to a device providing voice and/or data connectivity to a user. An access wireless terminal may be connected to a computing device such as a laptop computer or desktop computer, or it may be a self-contained device such as a cellular telephone. An access terminal can also be called a system, a subscriber unit, a subscriber station, mobile station, mobile, remote station, remote terminal, a wireless access point, wireless terminal, user terminal, user agent, user device, or user equipment. A wireless terminal may be a subscriber station, wireless device, cellular telephone, PCS telephone, cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, or other processing device connected to a wireless modem. An access point, otherwise referred to as a base station or base station controller (BSC), may refer to a device in an access network that communicates over the air-interface, through one or more sectors, with wireless terminals. The access point may act as a router between the wireless terminal and the rest of the access network, which may include an Internet Protocol (IP) network, by converting received air-interface frames to IP packets. The access point also coordinates management of attributes for the air interface. 
         [0023]    Moreover, various aspects or features described herein may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques. The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips . . . ), optical disks (e.g., compact disk (CD), digital versatile disk (DVD) . . . ), smart cards, and flash memory devices (e.g., card, stick, key drive . . . ), and integrated circuits such as read-only memories, programmable read-only memories, and electrically erasable programmable read-only memories. 
         [0024]    Various aspects will be presented in terms of systems that may include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches may also be used. 
         [0025]    Other aspects, as well as features and advantages of various aspects, of the present invention will become apparent to those of skill in the art through consideration of the ensuring description, the accompanying drawings and the appended claims. 
         [0026]      FIG. 1  illustrates a multiple access wireless communication system  100  according to one aspect. An access point  102  (AP) includes multiple antenna groups, one including  104  and  106 , another including  108  and  110 , and an additional one including  112  and  114 . In  FIG. 1 , only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal  116  (AT) is in communication with antennas  112  and  114 , where antennas  112  and  114  transmit information to access terminal  116  over downlink or forward link  118  and receive information from access terminal  116  over uplink or reverse link  120 . Access terminal  122  is in communication with antennas  106  and  108 , where antennas  106  and  108  transmit information to access terminal  122  over downlink or forward link  124 , and receive information from access terminal  122  over uplink or reverse link  126 . In a frequency division duplex (FDD) system, communication link  118 ,  120 ,  124 , and  126  may use a different frequency for communication. For example, downlink or forward link  118  may use a different frequency than that used by uplink or reverse link  120 . 
         [0027]    Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access point. In an aspect, antenna groups are each designed to communicate to access terminals in a sector of the areas covered by access point  102 . 
         [0028]    In communication over downlinks or forward links  118  and  124 , the transmitting antennas of an access point utilize beamforming in order to improve the signal-to-noise ration (SNR) of downlinks or forward links for the different access terminals  116  and  122 . Also, an access point using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access point transmitting through a single antenna to all its access terminals. 
         [0029]    An access point may be a fixed station used for communicating with the terminals and may also be referred to as a Node B, an evolved Node B (eNB), or some other terminology. An access terminal may also be called a mobile station, user equipment (UE), a wireless communication device, terminal or some other terminology. For certain aspects, either the AP  102 , or the access terminals  116 ,  122  may utilize the techniques described below to improve performance of the system. 
         [0030]      FIG. 2  shows a block diagram of an exemplary design of a wireless communication device  200 . In this exemplary design, wireless device  200  includes a data processor  210  and a transceiver  220 . Transceiver  220  includes a transmitter  230  and a receiver  250  that support bi-directional wireless communication. In general, wireless device  200  may include any number of transmitters and any number of receivers for any number of communication systems and any number of frequency bands. 
         [0031]    In the transmit path, data processor  210  processes data to be transmitted and provides an analog output signal to transmitter  230 . Within transmitter  230 , the analog output signal is amplified by an amplifier (Amp)  232 , filtered by a lowpass filter  234  to remove images caused by digital-to-analog conversion, amplified by a VGA  236 , and upconverted from baseband to RF by a mixer  238 . The upconverted signal is filtered by a filter  240 , further amplified by a driver amplifier,  242  and a power amplifier  244 , routed through switches/duplexers  246 , and transmitted via an antenna  249 . 
         [0032]    In the receive path, antenna  248  receives signals from base stations and/or other transmitter stations and provides a received signal, which is routed through switches/duplexers  246  and provided to receiver  250 . Within receiver  250 , the received signal is amplified by an LNA  252 , filtered by a bandpass filter  254 , and downconverted from RF to baseband by a mixer  256 . The downconverted signal is amplified by a VGA  258 , filtered by a lowpass filter  260 , and amplified by an amplifier  262  to obtain an analog input signal, which is provided to data processor  210 . 
         [0033]      FIG. 2  shows transmitter  230  and receiver  250  implementing a direct-conversion architecture, which frequency converts a signal between RF and baseband in one stage. Transmitter  230  and/or receiver  250  may also implement a super-heterodyne architecture, which frequency converts a signal between RF and baseband in multiple stages. A local oscillator (LO) generator  270  generates and provides transmit and receive LO signals to mixers  238  and  256 , respectively. A phase locked loop (PLL)  272  receives control information from data processor  210  and provides control signals to LO generator  270  to generate the transmit and receive LO signals at the proper frequencies. 
         [0034]      FIG. 2  shows an exemplary transceiver design. In general, the conditioning of the signals in transmitter  230  and receiver  250  may be performed by one or more stages of amplifier, filter, mixer, etc. These circuits may be arranged differently from the configuration shown in  FIG. 2 . Some circuits in  FIG. 2  may also be omitted. All or a portion of transceiver  220  may be implemented on one or more analog integrated circuits (ICs), RF ICs (RFICs), mixed-signal ICs, etc. For example, amplifier  232  through power amplifier  244  in transmitter  230  may also be implemented on an RFIC. Driver amplifier  242  and power amplifier  244  may also be implemented on another IC external to the RFIC. 
         [0035]    Data processor  210  may perform various functions for wireless device  200 , e.g., processing for transmitter and received data. Memory  212  may store program codes and data for data processor  210 . Data processor  210  may be implemented on one or more application specific integrated circuits (ASICs) and/or other ICs. 
         [0036]    Mobile devices, such as those described in  FIG. 2  rely on processors to perform many of the functions desired by users. As mobile devices perform more functions, the demands on the processors have escalated and processor complexity has increased. Many mobile devices use a single chip, known as a System-on-a-Chip (SoC) to perform the majority of tasks, including running applications. An advanced modem is a key part of the SoC. Testing such high frequency application is critical and requires accurate measurement and testing of radio frequency (RF) specifications including gain, isolation, harmonics, linearity, noise, and insertion loss for both test socket and probe card applications. 
         [0037]    One solution that has been used is membrane probing. Membrane probing has a higher contact resistance and lower direct current (DC) for wafers. An advantage is the lower parasitic inductance of the membrane probe head. Wafers contain multiple SoC devices and may be tested before the individual devices are separated. Unfortunately, membrane probing requires mounting a costly membrane probe head and the design of the membrane probe head is also high. Each SoC wafer requires a specially designed membrane probe head. Because membrane probe heads provide higher contact resistance a duty cycle is required, which increases testing time. 
         [0038]    An alternative to the membrane probe head is the spring probe. Spring probes are capable of handling higher DC currents than membrane probe heads. In addition, spring probes have lower contact resistance. However, spring probes also have the drawback of having larger parasitic inductance, which may create inaccurate measurements of gain, isolation, harmonics, linearity, noise, and insertion loss. 
         [0039]      FIG. 3  illustrates a typical test set-up. The test assembly  300  includes a probe interface board  302 . A probe card  304  is placed on one side of the probe interface board  302 . A core is placed on probe card  304  and a testing probe has access to the die during testing. 
         [0040]      FIG. 4  shows a cut-away view of a guided coaxial spring probe socket in use. The assembly  400  includes a top  402  and a pusher or retention spring  404 . Retention spring  404  helps maintain engagement between the pu into insert  408  sher tip  418  and top  402 . A pusher shim  406  ensures good contact between pusher tip  418  and top  402  and also allows for adjustments. Top  402  fits into insert  408 , which also hold the device being tested  410 . Device  410  is placed into socket  420  and socket shim  422  assures correct fit and placement. Socket guide  412  acts in conjunction with socket guide shim  414  and insert  408  to retain device  410  in position for testing. During testing pins  416  make contact with the pads on device  410 . This contact is also depicted in  FIG. 4 , in the accompanying illustration where the compressed and uncompressed states of the guided coaxial spring probes are depicted. 
         [0041]      FIG. 5  shows the signal transmission through the pin  416  to the pad on the device being tested  410 . In addition, ground signals are also shown in  FIG. 5 . This signal transmission occurs during testing. One advantage to the guided coaxial spring probe socket is that it is suitable for use with a convention signal net and ground net. 
         [0042]      FIG. 6  depicts one guided coaxial spring probe assembly  600 . Spring probe assembly  600  is one of multiple guided coaxial spring probes forming a testing socket  400  as shown in  FIG. 4 . Guided coaxial spring probe assembly  600  includes conductor  602 , dielectric  604 , and shield  605 . These components act to transmit signals as shown in the illustration. Signal transmission is provided by solder ball  608  which makes contact with the device  410  pads. Solder ball  608  is placed at one end of probe head  610 . Probe head  610  extends from barrel  612 . Barrel  612  contains spring  614 . Probe bottoms  616  act as limits on guided coaxial spring probe travel during use. In use, each guided coaxial spring probe behaves as an inductance in series and a capacitor in parallel, as illustrated in  FIG. 6 . The behavior of guided coaxial spring probe  600  may be approximated to that of a first order approximation wire representation by the formula: 
         [0000]        Z   O =( L/C ) 1/2    
         [0043]    In operation the guided coaxial spring probe pin provides significantly improved RF signal transition and also provides minimum parasitic inductance to solve difficult RF specification measurement issues. The electromagnetic field, guided by the coaxial line minimizes signal loss and impedance matching, moving closer to a perfect transmission line. Current passes through the dielectric inner medium  604  and the outer plated shield  606  to create a coaxial electromagnetic field pattern generated by conductor  602 . 
         [0044]      FIG. 7  depicts the signal and ground net of each guided coaxial spring probe assembly  700 . Conductor  702  resides within dielectric  704 . Dielectric  704  is a microtube with an inner surface signal net and an outer surface ground net. Spring  706  contains both conductor  702  and dielectric microtube  704 . Barrel  708  contains spring  706 , dielectric  704  and conductor  702 . 
         [0045]      FIG. 8  provides further details of the operation of the inner or signal net and the outer metal or ground net. The electromagnetic field is coaxial, as shown in  FIG. 8 . The energy propagates in an axial region between the inner or signal net conductor and the outer metal or ground net. 
         [0046]      FIG. 9  shows the improvements possible through use of the guided coaxial spring probe socket described above. Insertion loss on the tested lines was 0.03 dB at 2.5 GHz for the simulation testing. Isolation was also better, with −30 dB improvement, due to better shielding on the guided coaxial spring probe. In addition, parasitic inductance was significantly decrease, with approximately a 60% drop, and a result of 0.35 nH. These simulation results arise because, with the exception of the probe heads, the guided coaxial spring probe may be considered a part of the coaxial transmission line. As a result, isolation and insertion loss are nearly the same as for coaxial transmission lines. 
         [0047]      FIG. 10  is a flowchart of a method of testing a device using a guided coaxial spring probe socket. The method  1000  begins in step  1002   v  when the device to be tested is installed into the test socket guide. In step  1004  the pusher tip is installed on top of the device and through a spring pushes down on the device to be tested. A check is made in step  1006  to ensure that the guided coaxial spring probe socket pins engage the device pads. Testing begins when test signals are toured through the guided coaxial spring probe socket pines. Finally, in step  1010  test results are recorded. 
         [0048]    The method and apparatus described above provide advantages over current test methodologies. Memory probing requires a 25% duty cycle with cleaning of the probe required in between tests. Using the guided coaxial spring probe described above reduces test time because it provides a greater duty cycle and does not need to be cleaned. A further advantage of the guided coaxial spring probe is that the lower parasitic inductance and contact resistance, along with a larger DC current, allows testing of high power devices without disturbing the loading conditions. A greater benefit is that more accurate measurement and testing of RF specifications such as gain, isolation, harmonics, linearity, noise, and insertion loss are possible, due to the lower parasitic inductance. 
         [0049]    Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
         [0050]    Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the exemplary embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the exemplary embodiments of the invention. 
         [0051]    The various illustrative logical blocks, modules, and circuits described in connection with the exemplary embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
         [0052]    In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitter over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM EEPROM, CD-ROM or other optical disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. 
         [0053]    The previous description of the disclosed exemplary embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these exemplary embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the exemplary embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Technology Classification (CPC): 6