Patent Publication Number: US-9846831-B2

Title: Interface IC and memory card including the same

Description:
INCORPORATION BY REFERENCE 
     The present application is a Continuation Application of U.S. patent application Ser. No. 13/964,446, filed on Aug. 12, 2013, which is a Continuation Application of U.S. patent application Ser. No. 12/923,928, filed on Oct. 14, 2010, now U.S. Pat. No. 8,534,563, which is based and claims priority from Japanese Patent Application No. 2009-238173, filed on Oct. 15, 2009, the entire contents of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to an interface IC and a memory card including the same. 
     2. Description of Related Art 
     Memory cards having a flash memory built therein are widely used as storage media for use in a portable game machine, a digital camera, an IC recorder, a cellular phone, or the like.  FIG. 5  is a plan view showing an internal structure of a typical contact type memory card. 
     The memory card shown in  FIG. 5  includes a printed circuit board  1 , a flash memory  2  that stores data, data pins  3  that are external terminals for data transfer, a power supply pin  4   a  that connects to a power supply, a ground pin  4   b  that connects to ground, and wiring lines  5 . In the memory card of  FIG. 5 , data is transferred to a main unit, into which the memory card is inserted, through the data pins  3 . 
     In the contact type memory card using such data pins, a contact failure may occur. In this regard, Japanese Unexamined Patent Application Publication No. 8-147079 discloses a non-contact type memory card using magnetic coupling of coils in place of the data pins. 
     As a related art, Japanese Unexamined Patent Application Publication No. 2008-283172 discloses a semiconductor device for RFID (Radio Frequency Identification) in which an antenna is integrated with an IC. Further, Japanese Unexamined Patent Application Publication No. 2000-215681 discloses a mask ROM (Read Only Memory) having a scrambling device. 
     SUMMARY 
     The present inventors have found problems as described below. In the contact type memory card shown in  FIG. 5 , the data stored in the flash memory  2  may be easily read out by contacting a probe to the data pins  3 , for example. This may cause a problem that even if game software used for a portable game machine is encrypted and stored in a memory card, for example, it is easily read out and cryptanalyzed by a so-called hacker or the like. In short, such game software has low tamper resistance. Further, such a contact type memory card shown in  FIG. 5  is composed of commercial parts. Therefore, illegal copies (so-called “pirated copies”) of the cryptanalyzed game software can easily be made. 
     A first exemplary aspect of the present invention is a memory card that includes a memory that stores data, a driver that transmits the data received from the memory, and at least one transmitter that transmits the data received from the driver to a receiver provided in an external main unit, wherein the driver and the at least one transmitter are provided in a single IC (integrated circuit) chip and are not overlapped with each other in a planar view. 
     The at least one transmitter can include a coil. The at least one transmitter can include a plurality of transmitters. The plurality of transmitters can transmit the data to the receiver alternately. The plurality of transmitters transmit the data to the receiver randomly. The memory card can further include a clock receiver that receives a clock signal from the external main unit. A size of the at least one transmitter differs from a size of the clock receiver. The memory card can include an encrypting circuit that encrypts the data received from the memory and transmits the encrypted data to the driver. The encrypting circuit can be provided in the IC chip. The memory can be provided in the IC chip. The data stored in the memory can be a game software. 
     Another exemplary aspect of the present invention is an interface IC (integrated circuit) provided in a memory card so as to transmit data from the memory card to a main unit into which the memory card is inserted, the interface IC including a driver that transmits the data received from a memory of the memory card, and at least one transmitter that transmits the data received from the driver to a receiver provided in the main unit, wherein the driver and the at least one transmitter are provided in a single IC chip and are not overlapped with each other in a planar view. 
     The at least one transmitter can include a coil. The at least one transmitter can include a plurality of transmitters. The plurality of transmitters can transmit the data to the receiver alternately. The plurality of transmitters can transmit the data to the receiver randomly. The interface IC can further include a clock receiver that receives a clock signal from the main unit and is provided in the IC chip. A size of the at least one transmitter can differ from a size of the clock receiver. 
     In the exemplary aspects of the present invention, the driver and the transmitter are provided in a single IC chip. This makes it possible to increase the tamper resistance and to prevent illegal copies. 
     According to the exemplary aspects of the present invention, it is possible to provide a memory card capable of increasing the tamper resistance and preventing illegal copies. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other exemplary aspects, advantages and features will be more apparent from the following description of certain exemplary embodiments taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A  is a plan view showing an internal structure of a memory card according to a first exemplary embodiment; 
         FIG. 1B  is a cross-sectional view of an interface IC  106 ; 
         FIG. 2  is a plan view showing an internal structure of a variant of the memory card according to the first exemplary embodiment; 
         FIG. 3  is a plan view showing an internal structure of another variant of the memory card according to the first exemplary embodiment; 
         FIG. 4  is a plan view showing an internal structure of a memory card according to a second exemplary embodiment; and 
         FIG. 5  is a plan view showing an internal structure of a typical contact type memory card. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to exemplary embodiments described below. The following description and the accompanying drawings are appropriately simplified to clarify the explanation. 
     First Exemplary Embodiment 
       FIG. 1A  is a plan view showing an internal structure of a memory card according to a first exemplary embodiment of the present invention. A memory card  100  shown in  FIG. 1A  is a memory card that stores game software for a portable game machine, for example. The memory card  100  shown in  FIG. 1A  includes a printed circuit board  101 , a flash memory  102 , a power supply pin  104   a , a ground pin  104   b , a wiring line  105 , an interface IC  106 , a clock receiving coil  107   a , a data transmitting coil  107   b , a driver  108 , and a bus  109 . 
     On the other hand, a main unit  10  that corresponds to a portable game machine, for example, includes a power supply pin  14   a , a ground pin  14   b , wiring lines  15 , an interface IC  16 , a clock transmitting coil  17   a , a data receiving coil  17   b , a receiver  18 , and a bus  19 . 
     The flash memory  102  is an independent IC chip provided on the printed circuit board  101 . The flash memory  102  stores game software for a portable game machine, for example. 
     The power supply pin  104   a  for connecting to a power supply and the ground pin  104   b  for connecting to ground are metal terminals composed of a copper alloy, for example. The power supply pin  104   a  and the ground pin  104   b  are provided on the printed circuit board  101 . When the memory card  100  is inserted into the main unit  10 , the power supply pin  104   a  and the ground pin  104   b  contact and electrically connect to the power supply pin  14   a  and the ground pin  14   b  of the main unit  10 , respectively. Therefore, a power supply voltage VDD and a ground voltage GND are applied to the power supply pin  104   a  and the ground pin  104   b , respectively, through the main unit  10 . 
     Here, coils connecting for a power supply/ground may be provided in place of the power supply pin  104   a  and the ground pin  104   b . However, the use of the power supply pin  104   a  and the ground pin  104   b  provides more stable voltages. 
     The interface IC  106  is an independent IC chip provided on the printed circuit board  101 . To the interface IC  106 , the power supply voltage VDD and the ground voltage GND are applied through the wiring line  105  formed on the printed circuit board  101 . On the interface IC  106 , the clock receiving coil  107   a , the data transmitting coil  107   b , and the driver  108  are formed. 
     The clock receiving coil  107   a  and the data transmitting coil  107   b  are composed of spiral wiring patterns formed on the surface of the interface IC  106 . When the memory card  100  is inserted into the main unit  10 , the clock receiving coil  107   a  and the data transmitting coil  107   b  are magnetically connected, in a non-contact manner, to the clock transmitting coil  17   a  and the data receiving coil  17   b  of the main unit  10  at a distance of about 3 mm, respectively. Note that the clock receiving coil  107   a  is not necessarily provided if data transfer is performed without synchronizing the clock. 
     The clock receiving coil  107   a  receives the clock from the main unit  10 . Meanwhile, the data stored in the flash memory  102  is transmitted to the main unit  10  through the data transmitting coil  107   b  and the data receiving coil  17   b . Note that the data received through the data receiving coil  17   b  is demodulated and serial/parallel-converted by the receiver  18  formed on the interface IC  16  of the main unit  10 . Then, the data is stored to a RAM (Random Access Memory) of the main unit  10  through the bus  19 . The RAM is not illustrated. 
     The driver  108  is a drive circuit formed on the interface IC  106 . The driver  108  receives the parallel data stored in the flash memory  102  through the bus  109  formed on the printed circuit board  101 . Then, the driver  108  parallel/serial-converts and modulates the data received from the flash memory  102  according to the clock received through the clock receiving coil  107   a , and transmits the data to the data transmitting coil  107   b.    
       FIG. 1B  is a cross-sectional view of the interface IC  106  taken along the line IB-IB of  FIG. 1A . The right side of  FIG. 1B  shows a coil forming region in which the clock receiving coil  107   a  and the data transmitting coil  107   b  are formed. The left side of  FIG. 1B  shows a driver forming region in which the driver  108  is formed. As shown in  FIG. 1B , the interface IC  106  has a layer structure that includes a semiconductor substrate  51  composed of silicon, for example, a wiring multilayer  52 , and a surface insulation film  53 . 
     In the driver forming region, a MOS transistor that constitutes the driver  108  is formed. The MOS transistor has two diffusion regions (a source region and a drain region) DL formed in the semiconductor substrate  51 , and a gate electrode GE formed on the semiconductor substrate  51  between the two diffusion regions DL. The gate electrode GE is composed of a polysilicon layer, for example. The two diffusion regions DL connect to wiring lines WL 1  through contacts CT 1 , respectively. An isolation layer IL is formed around the MOS transistor. At an end of the driver forming region, the surface insulation film  53  is removed, and a data input terminal DIN is formed in the uppermost layer of the wiring multilayer  52 . 
     In the coil forming region, the clock receiving coil  107   a  and the data transmitting coil  107   b  are formed in the uppermost layer of the wiring multilayer  52 . The data transmitting coil  107   b  is shown in  FIG. 1B . Both ends of the data transmitting coil  107   b  having a spiral shape connect to wiring lines WL 2  through contacts CT 2 , respectively. 
     The memory card  100  according to the first exemplary embodiment prevents the data stored therein from being easily illegally cryptanalyzed and has a more excellent tamper resistance than a contact type one, because the memory card  100  is a non-contact type with the data transmitting coil  107   b . Further, the interface IC  106  in which the data transmitting coil  107   b  is formed is a dedicated part of the memory card  100 . This makes it extremely difficult to duplicate the data stored in the memory card  100  and makes it possible to prevent illegal copies from being made. 
       FIG. 2  is a plan view showing an internal structure of a variant of the memory card according to the first exemplary embodiment. As shown in  FIG. 2 , a plurality of data transmitting coils  107   b  may be provided. Further, as shown in  FIG. 2 , it is possible to increase the tamper resistance by transmitting the data using two data transmitting coils  107   b  alternately or randomly. Note that the size of the data transmitting coil  107   b  may differ from the size of the clock receiving coil  107   a . Specifically, the data transmitting coil  107   b  may be smaller than the clock receiving coil  107   a.    
       FIG. 3  is a plan view showing an internal structure of another variant of the memory card according to the first exemplary embodiment. As shown in  FIG. 3 , the flash memory  102 , the data transmitting coil  107   b , the clock receiving coil  107   a , and the driver  108  may be formed on the interface IC  106 . In other words, the interface IC  106  and the flash memory  102  shown in  FIG. 1A  may be formed on a single IC chip. This makes it difficult to duplicate the data stored in the memory card  100  and makes it possible to prevent illegal copies from being made. 
     Further, as shown in  FIG. 3 , the data transmitting coil  107   b  and the clock receiving coil  107   a  may be formed on the driver  108 . This configuration allows downsizing. 
     Second Exemplary Embodiment 
     Next, a second exemplary embodiment of the present invention is described hereinafter with reference to  FIG. 4 .  FIG. 4  is a plan view showing an internal structure of a memory card according to a second exemplary embodiment. As shown in  FIG. 4 , the memory card  200  according to the second exemplary embodiment has an MCU  110  provided between the driver  108  and the flash memory  102  in the memory card  100  according to the first exemplary embodiment shown in  FIG. 1A . Other structures are similar to those in the first exemplary embodiment, and thus description thereof will be omitted. 
     The MCU (Memory Control Unit)  110  is a control circuit that controls the flash memory  102 . The MCU  110  is formed on the interface IC  106 . The MCU  110  receives the parallel data stored in the flash memory  102  through the bus  109 . Then, the MCU  110  encrypts the data received from the flash memory  102  according to the clock received through the clock receiving coil  107   a , and transmits the data to the driver. In short, the MCU  110  according to the second exemplary embodiment has a function as an encrypting circuit. This further improves the tamper resistance. 
     Note that capacitor coupling (electrostatic coupling) or an extremely short distance radio communication using an antenna coil may be used in place of the coil coupling (magnetic coupling). Here, the signal transmission distance in the magnetic coupling is about 1 to 3 mm. On the other hand, the signal transmission distance in the extremely short distance radio communication is about 10 mm. Therefore, the magnetic coupling has less transmission errors. Further, the magnetic coupling prevents data from being intercepted and has a more excellent tamper resistance. 
     While the invention has been described in terms of several exemplary embodiments, those skilled in the art will recognize that the invention can be practiced with various modifications within the spirit and scope of the appended claims and the invention is not limited to the examples described above. 
     Further, the scope of the claims is not limited by the exemplary embodiments described above. 
     Furthermore, it is noted that, Applicant&#39;s intent is to encompass equivalents of all claim elements, even if amended later during prosecution.