JP2008191995A - Ic card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IC card capable of electrically detecting the cracks of an IC chip and preventing the occurrence of future breakdown of the IC chip. <P>SOLUTION: An IC chip 4 is formed in a circuit forming layer 6, with a resin layer 8 being laminated. In a surface 8a, separated from the circuit forming layer 6 of the resin layer 8, a circuit pattern 10 is formed. When a crack that does not reach the circuit forming layer 6, is produced from the surface 8a side of the resin layer 8, since the possibility is high that this crack will reach the circuit forming layer 6 in the future, the fracture of the circuit pattern 10 due to the crack is detected, and the breakdown of the IC chip 4 is prevented from occurring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an IC card having an IC chip mounted on a card body.

  Conventionally, as an IC chip to be mounted on a card body, an IC chip in which a mirror surface and a side surface of an IC chip are etched to remove chipping generated in the IC chip during dicing, and the bending strength of the IC chip is increased. Is known (for example, see Patent Document 1). Generally, since an IC card is carried and used, it is effective to increase the durability of the card due to external stress to increase the bending strength of the IC chip by processing the chipping in this way.

However, scratches (cracks) on the surface of the IC chip thus generated in the manufacturing process cannot be completely removed by the etching process described above. For this reason, scratches on the surface of the IC chip in the manufacturing process may become large in the future and cause destruction of the IC chip.
JP 2000-99678 A

  An object of the present invention is to provide an IC card that can electrically detect cracks in an IC chip and prevent future destruction of the IC chip.

  In order to achieve the above object, an IC card according to the present invention includes an IC chip having at least a circuit forming layer having a circuit pattern formed on the surface thereof, and a resin layer laminated on the surface of the circuit forming layer, and the IC chip. And the resin layer has a wiring pattern that is broken by a crack that does not reach the circuit forming layer.

  According to the above invention, by detecting the breakage of the wiring pattern formed in the resin layer of the IC chip, it is possible to detect a crack that has not reached the circuit formation layer and is likely to lead to the destruction of the chip in the future. Therefore, it is possible to prevent future destruction of the IC chip and to provide an IC card on which a more reliable IC chip is mounted.

  Since the IC card of the present invention has the configuration and operation as described above, it is possible to electrically detect cracks in the IC chip and prevent future destruction of the IC chip.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an equivalent circuit of a wireless IC card 1 (hereinafter simply referred to as an IC card 1) according to an embodiment of the present invention. The IC card 1 includes an antenna coil 2 and an IC chip 4 for wireless communication with a reader / writer (not shown). The IC chip 4 is mounted on the card body provided with the antenna coil 2.

  This IC card 1 receives magnetic force lines supplied via an antenna (not shown) of the reader / writer via an antenna coil 2 and converts it into electric power, and this electric power operates a CPU (to be described later) of the IC chip 4 to perform the remaining operation. A response is returned to the reader / writer with power. Thus, the IC card 1 performs data communication with the reader / writer in a non-contact manner.

  FIG. 2 is a schematic cross-sectional view of the IC chip 4. The IC chip 4 includes a circuit forming layer 6 having a circuit pattern (described later) formed on at least the surface 6a, and a resin layer 8 laminated on the surface 6a. The resin layer 8 is formed of silicon and is laminated for the purpose of protecting the circuit pattern on the surface 6a of the circuit forming layer and ensuring the strength of the chip. Further, since the thickness of the resin layer 8 is determined in accordance with the standard of the thickness of the IC card 1 as a product, the resin layer 8 is cut to adjust the thickness of the IC chip 4 to a desired thickness. Here, the detailed description of the structure of the circuit forming layer 6 is omitted.

  In the manufacturing process of the IC chip 4, when a crack 7 (break) occurs in the circuit forming layer 6, the circuit pattern is disconnected or an electronic component such as a CPU breaks down, and the IC chip 4 becomes inoperable. . However, when the crack 9 is generated from the surface 8a side of the resin layer 8 with a size that does not reach the circuit forming layer 6, the IC chip 4 can operate. For this reason, conventionally, even if there is a crack 9 on the resin layer 8 side of the IC chip 4, it is used as it is unless an inoperability is detected in the inspection process.

  However, the crack 9 generated on the resin layer 8 side may reach the circuit forming layer 6 in the future, and the IC card 1 mounted with the IC chip 4 on which such a crack 9 has been generated is shipped. If this happens, the IC card 1 is likely to become inoperable in the future. In other words, in this way, even if the crack 9 on the resin layer 8 side that does not affect the operation of the IC chip 4 is apparently likely to be destroyed over time, the reliability of the product is high. It is not possible to overlook this situation.

  For this reason, in this embodiment, as shown in FIG. 3, a fine wiring pattern 10 composed of a single continuous line is formed on the surface 8a of the resin layer 8 of the IC chip 4 spaced from the circuit forming layer 6. The above-described crack 9 on the resin layer 8 side is detected by electrically detecting that the wiring pattern 10 is broken by a detection circuit described later. In other words, the wiring pattern 10 is formed on the surface 8a of the resin layer 8 in a position and shape that breaks when a crack 9 occurs on the surface 8a. The IC chip 4 that has detected the crack 9 is discarded without being shipped as it is.

  The wiring pattern 10 of the present embodiment is formed by, for example, printing silver paste on the surface 8a, is long in the direction intersecting with the direction in which the crack 9 is likely to occur, the interval between adjacent line segments is as narrow as possible, and It is formed in a zigzag manner in a region covering substantially the entire surface 8a. When the direction of the crack 9 can be predicted in advance, the wiring pattern 10 is extended in a direction in which the wiring pattern 10 is surely cut by the crack 9, that is, in a direction crossing the crack 9. Further, both ends of the wiring pattern 10 end at two adjacent corners of the IC chip 4, and connection terminals 11a and 11b are provided, respectively.

  As shown in FIG. 4, four connection terminals 12 a, 12 b, 13 a, and 13 b are provided at the four corners on the back surface 6 b side of the circuit forming layer 6 of the IC chip 4. Two ends of the antenna coil 2 described above are connected to the two connection terminals 12a and 12b. The remaining two connection terminals 13 a and 13 b are provided in a positional relationship facing the two connection terminals 11 a and 11 b of the wiring pattern 10 described above in the thickness direction of the IC chip 4.

  That is, for example, as shown in FIG. 5A, when the above-described IC chip 4 is mounted on a card body side substrate by flip chip, both ends of the antenna coil 2 patterned on the substrate are on the back surface of the IC chip 4. Connected to two connection terminals 12a and 12b, and the remaining two connection terminals 13a and 13b are respectively connected to independent wirings 14a and 14b on the substrate.

  FIG. 5B shows a schematic plan view of the IC chip 4 viewed from the substrate side. According to this, the two connection terminals 13a and 13b to which the antenna coil 2 of the IC chip 4 is not connected are respectively connected to two elongated wires 14a and 14b that are independently patterned on the substrate. Further, the connection terminals 11a and 11b of the wiring pattern 10 formed on the surface 8a of the resin layer 8 of the IC chip 4 are connected to the two wirings 14a and 14b via wires 15a and 15b, respectively. (FIG. 5a).

  FIG. 6 shows an equivalent circuit (detection circuit) for detecting the breakage of the wiring pattern 10 described above. As described above, the antenna coil 2 is included in the closed circuit connecting the connection terminal 13a of the IC chip 4, the wire 15a, the connection terminal 11a of the wiring pattern 10, the wiring pattern 10, the connection terminal 11b, the wire 15b, and the connection terminal 13b. A power source 21 to which power is supplied via is connected. In addition, a resistor 22 having one end connected to the ground is connected to the closed circuit. For this reason, when operating power is supplied to the IC chip 4, a current flows through the resistor 22 and a voltage is generated at both ends thereof.

  That is, in a state where the wiring pattern 10 on the IC chip surface 8a is not broken, a current flows through the resistor 22 through the above-described closed circuit. By detecting the voltage across the resistor at this time via the input port 23, The CPU 20 can detect that there are no cracks 9 on the IC chip surface 8a. On the other hand, when the wiring pattern 10 is broken, since no current flows through the resistor 22, the CPU 20 can detect that the crack 9 is generated on the IC chip surface 8a when there is no voltage across the resistor.

  FIG. 7 shows a flowchart for explaining the inspection process of the IC card 1 on which the IC chip 4 is mounted. In this inspection process, the IC card 1 on which the above-described IC chip 4 is mounted is inspected on the reader / writer antenna of an inspection device (not shown).

  When the IC card 1 is trapped by the antenna of the inspection apparatus, the antenna coil 2 of the IC card 1 blocks the magnetic field lines generated from the antenna, and operating power is supplied to the IC card 1 to activate the IC card 1. (Step 1). At this time, the CPU 20 of the IC chip 4 detects whether or not a voltage is generated at both ends of the resistor 22 (step 2), and detects whether or not the crack 9 is generated on the IC chip surface 8a.

  When the CPU 20 detects the presence of voltage in the processing of step 2 (step 2; YES) and detects that no crack 9 is generated on the surface 8a side, the CPU 20 responds to a polling command from the reader / writer (step 3; YES) Normal response processing is executed, and the IC card 1 is normally operated (step 4). At this time, the reader / writer that has received a normal reply from the IC card 1 determines that the IC card 1 is a normal card that operates normally, and notifies the operator of the inspection apparatus via a display unit (not shown). Notice.

  On the other hand, when no voltage is detected in step 2 (step 2; NO), the CPU 20 detects that a crack 9 is generated on the surface 8a of the IC chip 4 (step 5). Thereafter, the CPU 20 waits for an initial command from the reader / writer (step 6; YES), and notifies the reader / writer of the inspection apparatus that there is a crack 9 (step 7).

  Accordingly, the inspection apparatus determines that the IC chip 4 of the IC card may be destroyed in the future, and notifies the operator that the IC card 1 should be discarded via the display unit. To do.

  As described above, according to the present embodiment, the wiring pattern 10 is formed on the surface 8a spaced from the circuit forming layer 6 of the IC chip 4, and the breakage of the wiring pattern 10 due to the crack 9 on the surface 8a is detected by the CPU 20 of the IC chip 4. Therefore, the crack 9 that is likely to reach the circuit formation layer 6 in the future can be found at an early stage, and the reliability of the IC card 1 on which the IC chip 4 is mounted can be improved.

  In the above-described embodiment, the case where the crack 9 is detected in the inspection process of the IC card 1 has been described. However, after the IC card 1 is shipped, the IC card 1 can be connected with the reader / writer of the data processing device during normal use. Thus, the presence or absence of the crack 9 may be detected when data communication is performed, and the IC card 1 with a high possibility of destruction of the IC chip 4 can be found at an early stage and services such as replacement can be provided.

  In the above-described embodiment, the case where the present invention is applied to the wireless IC card 1 including the antenna coil 2 for performing wireless communication with the reader / writer has been described. It can also be applied to a contact type IC card that does not have the antenna coil 2.

  Further, in the above-described embodiment, the example in which the crack 9 of the IC chip 4 is detected and prompted to be discarded or replaced at the time of inspection and use of the IC card 1 has been described. The IC card 1 mounted with 4 may be disabled.

  FIG. 8 is a diagram for explaining another embodiment of the present invention. In the following description, the same reference numerals are given to components that function in the same manner as the above-described embodiment, and detailed description thereof is omitted. Here, a method for disabling the IC card 1 on which the IC chip 4 is mounted when a crack 9 is generated on the surface 8a of the resin layer 8 spaced from the circuit forming layer 6 of the IC chip 4 will be described. .

  FIG. 8A shows a schematic side view of the IC chip 30 mounted on the substrate on which the antenna coil 31 is formed, and FIG. 8B shows the structure of FIG. 8A viewed from the substrate side. A schematic diagram of the back side is shown.

  In this example, the connection terminals 11 a and 11 b of the wiring pattern 10 formed on the surface 8 a of the IC chip 30 are connected in the middle of the antenna coil 31. That is, in the present embodiment, the wiring pattern 10 is wired in the middle of the antenna coil 31. As a result, when the wiring pattern 10 is broken, the antenna coil 31 is also broken. At the same time as the crack 9 is generated, the IC card 1 mounted with the IC chip 30 becomes inoperable.

  Also in the IC card 1 of this embodiment, the crack 9 that is likely to lead to destruction of the IC chip 30 in the future can be electrically detected as in the above-described embodiment, and the IC chip 30 is simultaneously detected. The IC card 1 mounted with can be made inoperable, and future destruction of the IC chip 30 can be prevented in advance.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above. Furthermore, you may combine the component covering different embodiment suitably.

  For example, in the above-described embodiment, the case where the wiring pattern 10 shown in FIG. 3 is formed on the surface 8a of the resin layer 8 of the IC chip 4 has been described. However, the shape is not limited to this, and the shape of the wiring pattern 10 is arbitrarily changed. It is possible, and it may be formed not only on the surface 8a but also inside the resin layer 8. For example, when the wiring pattern 10 is formed near the boundary with the circuit forming layer 6, the wiring pattern 10 is broken immediately before the crack 9 generated from the surface 8 a side of the resin layer 8 reaches the circuit forming layer 6. The detection timing of the crack 9 can be brought close to the timing at which the IC chip is actually destroyed. In other words, the detection timing of the crack 9 can be changed to any timing by changing the distance from the boundary (surface 6a of the circuit forming layer 6) where the wiring pattern 10 is formed.

  Further, by forming the wiring pattern 10 at a position retracted from the surface 8 a of the resin layer 8, that is, inside the resin layer 8, the wiring pattern 10 is formed when the resin layer 8 is scraped to adjust the thickness of the IC chip 4. It is possible to prevent scraping.

  In the above-described embodiment, the case where the wiring pattern 10 is formed in a region covering substantially the entire surface 8a (or inside) of the resin layer 8 of the IC chips 4 and 30 has been described. A wiring pattern may be formed in at least one region by dividing into a plurality of regions in the plane direction.

  For example, the wiring pattern may be formed only in a region where the crack 9 is likely to occur in the manufacturing process of the IC chip or a region that leads to a serious defect when the crack 9 occurs. In this case, the silver paste for forming the wiring pattern can be reduced, and the manufacturing cost can be reduced accordingly. In addition, when the wiring pattern is wired in the middle of the antenna coil, the influence on the characteristics of the antenna coil can be reduced by forming the wiring pattern only in such a small region.

  Alternatively, independent wiring patterns may be formed in all the divided areas, and a detection circuit for detecting breakage may be connected to each wiring pattern to detect the crack 9. In this case, an area where the crack 9 is likely to be generated can be statistically determined, which can be used for maintenance and inspection of the IC chip manufacturing apparatus.

  Further, in the above-described embodiment, the case where the IC chips 4 and 30 are mounted on the substrate of the card body by the flip chip has been described. However, the present invention is applied to an IC card on which the IC chip is mounted by wire bonding. It can also be applied.

The figure which shows the equivalent circuit of the IC card which concerns on embodiment of this invention. Sectional schematic for demonstrating the crack of the IC chip mounted in the IC card of FIG. FIG. 2 is an external perspective view showing a wiring pattern of an IC chip mounted on the IC card of FIG. 1. The back surface schematic diagram which shows the connection terminal of the back surface side of IC chip. The figure for demonstrating the connection state of IC chip. The wiring diagram for demonstrating the detection circuit of a crack. The flowchart for demonstrating the method to detect a crack. The figure which shows the connection state of the IC chip which concerns on other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... IC card, 2 ... Antenna coil, 4, 30 ... IC chip, 6 ... Circuit formation layer, 6a ... Surface, 8 ... Resin layer, 8a ... Surface, 9 ... Crack, 10 ... Wiring pattern, 11a, 11b ... Connection Terminals, 14a, 14b ... wiring, 15a, 15b ... wire, 20 ... CPU, 22 ... resistance.

Claims (10)

An IC chip having at least a circuit forming layer having a circuit pattern formed on the surface, and a resin layer laminated on the surface of the circuit forming layer;
A card body on which the IC chip is mounted,
The IC card, wherein the resin layer has a wiring pattern that is broken by a crack that does not reach the circuit forming layer.   2. The IC card according to claim 1, wherein the wiring pattern is formed on a surface of the resin layer that is separated from the circuit forming layer.   The IC card according to claim 1, wherein the wiring pattern is formed inside the resin layer.   2. The IC card according to claim 1, wherein the IC chip includes a CPU for electrically detecting that the wiring pattern is broken.   When the CPU detects that the wiring pattern is broken during data processing with the reader / writer of the IC card, the CPU notifies the reader / writer that the IC chip is damaged. The IC card according to claim 4.   2. The IC card according to claim 1, wherein the IC chip has a detection circuit for electrically detecting that the wiring pattern is broken. The card body has an antenna coil for wireless communication with a reader / writer,
2. The IC card according to claim 1, wherein a wiring pattern of the IC chip constitutes a part of the antenna coil.   2. The IC card according to claim 1, wherein the wiring pattern is formed in a region covering substantially the entire resin layer.   2. The IC card according to claim 1, wherein the wiring pattern is formed in at least one region among a plurality of regions obtained by dividing the resin layer in the surface direction.   The IC card according to claim 1, wherein the wiring pattern includes a plurality of independent wiring patterns.

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