JP4659391B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device including a semiconductor chip and an antenna, and more particularly to a semiconductor device having a radio frequency identification (RFID) chip for determining the authenticity of a semiconductor chip.

  Conventionally, a semiconductor device including a semiconductor chip and an antenna is used for a non-contact IC card, an IC tag, and the like, and can transmit and receive signals wirelessly with a reader / writer. There is an advantage that there is no damage to the terminals and the like, and that the data is not easily falsified. As this type of semiconductor device, Japanese Patent Laid-Open No. 2001-52137 (Patent Document 1) discloses an IC chip and both ends of a coil for wireless communication connected to a pad portion of the IC chip, and an IC chip and an antenna coil. A semiconductor device integrated by resin molding is disclosed. Patent Document 1 discloses a semiconductor device in which an IC chip is directly connected to both ends of a planar antenna coil. In this case, the antenna coil can be configured by cutting the wiring support portion of the lead frame or the wiring tab.

  According to this configuration, the substrate on which the antenna coil and the IC chip are mounted can be eliminated, and thus the thickness of the semiconductor device can be reduced to about 0.3 to 0.5 mm.

  On the other hand, Japanese Patent Application Laid-Open No. 11-316809 (Patent Document 2) discloses a semiconductor device used for a game machine such as a pachinko machine or a pachislot machine. In order to determine whether the microprocessor IC or the memory IC is replaced with an illegal IC, the semiconductor device disclosed in Patent Document 2 uses an ID in addition to the first semiconductor chip such as the microprocessor IC and the memory IC. A second semiconductor chip storing a code is provided.

  More specifically, the first semiconductor chip is mounted on a lead frame, and a power supply voltage, a control signal, and data can be transmitted and received through the lead frame, while the second semiconductor chip is an antenna. The data can be transmitted independently of the first semiconductor chip via the antenna. Regardless of whether the first semiconductor chip is in operation or not, the second semiconductor chip transmits data to the external device, and the external device monitors the ID code, password, etc. of the second semiconductor chip. It is possible to determine whether one semiconductor chip has been replaced with an unauthorized IC.

  Further, Patent Document 2 discloses a semiconductor device having a two-layer structure in which a second semiconductor chip and an antenna coil are provided on a plane different from the lead frame on which the first semiconductor chip is mounted.

JP 2001-52137 A JP 11-316809 A

  Patent Document 1 discloses a semiconductor device in which a semiconductor chip is directly mounted on both ends of an antenna, and the antenna is configured by forming it in a coil shape with a lead frame. As shown in Patent Document 1, when a lead frame on which a semiconductor chip is mounted and a lead frame constituting an antenna are arranged in a plane, the thickness of the semiconductor device can be reduced, but the antenna is constituted. There is a disadvantage that the area occupied by the lead frame is increased and the planar area is increased.

  On the other hand, when a second semiconductor chip such as an RFID chip is stacked in two layers on a different surface from the first semiconductor memory such as a ROM as in Patent Document 2, an increase in planar area can be prevented. However, there is a drawback that the thickness of the semiconductor device is increased. In addition, in order to seal both semiconductor chips with a resin in a state where the two semiconductor chips have a two-layer structure, it is necessary to change the design of the package itself, and it is also difficult to manufacture. As a result, the semiconductor device disclosed in Patent Document 2 has a drawback that an increase in cost is inevitable.

  Further, Patent Documents 1 and 2 completely suggest that the antenna is configured by forming the lead frame in a coil shape, or that the antenna is configured separately from the lead frame and the space for housing the antenna is reduced. Not.

  An object of the present invention is to provide an antenna-mounted semiconductor device that can reduce the planar occupation area and also reduce the thickness.

  Another object of the present invention is to provide an antenna-mounted semiconductor device that effectively uses a lead frame for a semiconductor chip.

  Still another object of the present invention is to provide a semiconductor device having a structure suitable for an RFID chip.

According to a first aspect of the present invention, in a semiconductor device including a semiconductor chip and an antenna, the semiconductor device includes an island on which the semiconductor chip is mounted and a suspension pin that supports the island, and the antenna includes the suspension pin partially Are formed in the suspension pin by a slit formed by cutting out, and the slit extends in the length and width direction of the suspension pin, and the slit is a first slit portion extending in the width direction. A semiconductor device comprising a second slit portion that is continuous with the first slit portion and extends in the length direction is obtained.

  According to the present invention, by forming the antenna on a part of the lead frame, the lead frame itself can be provided with a function as an antenna in addition to the original function of the lead frame. Since it is not necessary to have a two-layer structure such as being provided on the semiconductor device, it is possible not only to simplify the semiconductor device manufacturing process but also to obtain a low-cost semiconductor device. Furthermore, in the present invention, since the conventional package can be used as it is, it is not necessary to develop a new package, and the cost can be greatly reduced.

  Referring to FIG. 1, a semiconductor device 10 according to an embodiment of the present invention is a rectangular SDIP (Shrink Dual In Package) type semiconductor device. Here, a state where a mold part forming a cover is removed is shown. It is shown. The present invention can be applied not only to the SDIP type semiconductor device but also to other types of semiconductor devices, for example, an SOP (Small Out-line Package) type semiconductor device and a QFP (Quad Flat Package) type semiconductor device. .

  The illustrated semiconductor device 10 includes a first semiconductor chip 11 such as a microprocessor IC and a memory IC and a lead frame 13. The lead frame 13 includes an island 131 on which the first semiconductor chip 11 is mounted, and the island 131. And the island 131 and a plurality of leads 133 arranged so as to surround the suspension pin 132. Of the lead frame 13, the lead 133 is connected to the pins 14 arranged at the top and bottom of the drawing along the longitudinal direction of the semiconductor device 10. The suspension pin 132 may be connected to the pin 14 connected to the ground.

  Furthermore, in the illustrated semiconductor device 10, a second semiconductor chip 12 storing an ID code is mounted in order to determine whether or not the first semiconductor chip 11 has been replaced with an unauthorized IC. The second semiconductor chip 12 shown in FIG. 1 is a radio frequency identification (RFID) chip.

  Here, the RFID chip is normally used as an IC tag as described in, for example, Japanese Patent Application Laid-Open No. 2001-250097, etc., and receives power supply and information from an external device in a non-contact manner. It is used for non-contact IC cards and the like that output information.

  An RFID chip used as the second semiconductor chip 12 will be schematically described with reference to FIG. The illustrated RFID chip (that is, the second semiconductor chip 12) includes two input / output terminals 16 and 17 to be connected to an antenna 15 that receives power and information from an external device. Here, the antenna 15 according to the present invention is formed on the suspension pin 132 of the lead frame 13 as described later.

  The RFID chip includes a resonance capacitor 18 and an information processing circuit 20 connected to input / output terminals 16 and 17. The information processing circuit 20 included in the RFID chip includes a microprocessor unit (MPU) 22 and an erasable nonvolatile memory 24 that stores an operation program and identification information of the MPU 22, and an antenna 15 and resonance from an external device. A smoothing rectification circuit 26 that smoothes and rectifies an alternating current wave having a predetermined frequency received via the capacitor 18 and converts it into direct current, and a communication control circuit 28 are included.

  The MPU 22 operates in accordance with the DC power from the smoothing rectifier circuit 26, the demodulated data from the communication control circuit 28, and the clock, and the data read from the nonvolatile memory 24 is modulated by the communication control circuit 28 and then the antenna 15 Is output to an external device. As is clear from this, the illustrated communication control circuit 28 includes a modulation / demodulation circuit, a clock recovery circuit, and a carrier generation circuit necessary for transmission / reception with an external device.

  The RFID chip having the illustrated configuration can exchange identification information with an external device in a contactless manner. As described above, such RFID chips are widely applied to game machines, IC cards, and the like.

  Returning to FIG. 1, the RFID chip constituting the second semiconductor chip 12 is mounted on the suspension pin 132 in the lead frame 13.

  Here, referring also to FIG. 3 showing an enlarged portion where the second semiconductor chip 12 is mounted, the suspension pin 132 extending in the longitudinal direction is formed by partially cutting the suspension pin 132. A slit 30 is formed, and the pattern region defined by the slit 30 can be operated as a slit antenna. More specifically, the illustrated slit 30 has a first slit portion extending in the width direction of the hanging pin 132 and a second slit portion extending in the longitudinal direction, and the second slit portion is the first slit. It continues to the portion and extends from the first slit portion in the right direction in the drawing, that is, in the direction away from the first semiconductor chip 11.

  The region of the suspension pin 132 defined below the second slit portion extending in the longitudinal direction constitutes an inductance component of the antenna 15. In other words, an antenna capable of transmitting and receiving a signal of a predetermined frequency can be configured by selecting the length of the second slit portion.

  In FIG. 3, the RFID chip constituting the second semiconductor chip 12 is mounted so as to straddle the first slit portion using the antenna obtained by cutting out the suspension pin 132. In the RFID chip shown in FIG. 2, the input / output terminals 16 and 17 are connected to points a and b of the suspension pin 132, respectively.

  In this configuration, when electromagnetic coupling or electromagnetic induction occurs between the external device and the RFID chip, the antenna inductance depends on the capacitance of the resonance capacitor 18 in the RFID chip and the length of the second slit portion. Resonance occurs in the RFID chip at a predetermined frequency defined by the components, and signals of the predetermined frequency can be transmitted and received. In this case, the suspension pin 132 is preferably connected to the pin 14 connected to the ground, and the RFID chip is preferably a diode-type RFID.

  The antenna according to the present invention will be further described with reference to FIG. Assuming that the width of the suspension pin 132 is W, the width of the slit is S, the length of the first slit portion is L1, and the length of the second slit portion is L2, L2 considers the half wavelength of the transmitted and received wavelengths. Further, S is determined to be 0.02 to 0.05 wavelength. Specifically, it has been found that L1 is preferably ½ or less of W and L2 is preferably 3 mm or more and 15 mm or less. It has also been found that S is preferably 200 μm, and the distance between the connection points a and b of the RFID chip is preferably 2.5 mm. Note that the length of L2 varies depending on the material of the antenna formation surface.

  The shape of the slit constituting the illustrated antenna is not limited to the illustrated slit, but can be changed to various shapes depending on the purpose and frequency.

  In the embodiment described above, only the case where the antenna is formed by providing the slit on the suspension pin 132 of the lead frame 13 has been described. However, the present invention is not limited to this, for example, the island 31 of the lead frame 13. Alternatively, a slit may be provided in another lead 133.

  In a semiconductor device including a lead frame, the present invention uses a lead frame as an antenna to mount a semiconductor chip storing identification information, such as an RFID chip, without changing the size, shape, etc. of the package. be able to.

It is a top view showing a semiconductor device concerning one embodiment of the present invention. It is a block diagram explaining the RFID chip | tip as a 2nd semiconductor chip shown by FIG. It is a figure which expands and shows a part of FIG. It is a figure explaining the specific example of the antenna which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 1st semiconductor chip 12 2nd semiconductor chip 13 Lead frame 131 Island 132 Suspension pin 133 Lead 14 Pin 15 Antenna 30 Slit 16, 17 Input / output terminal 18 Resonance capacitor 20 Information processing circuit 22 MPU
24 Memory 26 Rectifier / Smoothing Circuit 28 Communication Control Circuit

Claims (5)

In a semiconductor device including a semiconductor chip and an antenna, the semiconductor device includes an island on which the semiconductor chip is mounted and a suspension pin that supports the island.
The antenna is formed on the suspension pin by a slit formed by partially cutting the suspension pin,
The slit extends in a length and width direction of the suspension pin, and the slit is continuous with the first slit portion extending in the width direction, and the first slit portion extends in the length direction. 2. A semiconductor device having two slit portions . 2. The antenna according to claim 1 , wherein the portion of the suspension pin surrounded by the first and second slit portions has an inductance component of the antenna whose size is determined by the length of the second slit portion, and the first antenna. A semiconductor device characterized in that a signal having a predetermined frequency defined by the resonance capacitors disposed on both sides of the slit portion is transmitted and received. 3. The semiconductor device according to claim 1, wherein the length of the first slit portion is ½ or less of the width of the suspension pin . 4. The semiconductor device according to claim 1, wherein the suspension pin in which the first and second slits are formed is connected to a ground terminal. 5. The semiconductor device according to claim 1 , further comprising an RFID chip that straddles the first slit portion and is connected to the suspension pins on both sides of the stride.

Images