IC card and IC chip module

In an IC card 30 is sealed an IC chip 70 provided with an exposure sensor 84. When exposure sensor 84 detects that IC card 30 has been opened, exposure sensor 84 outputs an exposure detection signal to a CPU 76. In response to the exposure detection signal, CPU 76 provides a predetermined operation, such as erasure of data in a non-volatile memory 78. As such, the data in non-volatile memory 78 cannot be obtained if IC card 30 is improperly opened to check the data in non-volatile memory 78. Thus the IC card can obtain an enhanced data security.

TECHNICAL FIELD

The present invention relates to IC cards and IC chip modules and in particular to IC cards and IC chip modules with enhanced security.

BACKGROUND ART

A communication system employing a non-contact IC card is used for automatic ticket-gates of ski lifts, railroads and the like, automatic freight-sorting, and the like.FIG. 15is a perspective view showing one example of a conventional non-contact IC card. An IC card2shown inFIG. 15is a 1-coil IC card comprised of a coil4used as an antenna, capacitors C1and C2, and an IC chip8.

Capacitors C1, C2and IC chip8are mounted to a synthetic resin substrate in the form of a film. The substrate with capacitors C1, C2and IC chip8mounted thereto is referred to as a tape automated bonding (tab)10.

FIG. 16Ais a cross section of theFIG. 15IC card2taken along line S1—S1. In the figure, a core member12of synthetic resin is sandwiched by paired surface members14and16. Tab10with capacitors C1, C2and IC chip8mounted thereto is fixed to surface member14exposed in a cavity18provided in core member12. A joint of tab10and IC chip8is covered with a sealing agent9such as epoxy resin. Coil4is arranged between surface member14and core member12. Coil4and tab10are connected together via a wire20.

FIG. 16Bis a circuit diagram of IC card2. Referring to the figure, in IC card2an electromagnetic wave sent from a reader/writer (an interrogator (not shown)) is received at a resonator circuit22configured of coil4and capacitor C1and it is used as a power supply. It should be noted that capacitor C2is a power smoothing capacitor.

Furthermore, information superimposed on the electromagnetic wave and thus sent therewith is decrypted by a control unit (not shown) provided in IC chip8. The control unit then rewrites a content of a non-volatile memory (not shown) provided in IC chip8, makes a response to the reader/writer, and the like. The response is made by varying an impedance of resonator circuit22. The reader/write obtains the content of the response by detecting an impedance variation (an impedance reflection) of its resonator circuit (not shown) that is associated with the impedance variation of IC card2resonator circuit22.

As such, IC card2does not require an internal power supply and also allows non-contact communication of data.

However, conventional IC card2has the following disadvantage: in conventional IC card2, a pad (or a terminal) (not shown) used for checking the performance of a mounted non-volatile memory or the like in the process for manufacturing the same is provided on a surface of IC chip8. As such, the pad is exposed when surface members14,16are removed. By applying a probe (an inspecting needle) on the exposed pad, the data in the non-volatile memory can readily be read and IC chip8can be operated. That is, the conventional IC card does not have high data security. Furthermore, as shown inFIG. 17, there is also an IC card which mounts to tab10two IC chips, i.e., an IC chip6with a control unit (not shown) and an IC chip7with a non-volatile memory (not shown). In such a type of IC card, in addition to the pad mentioned above a wire24connecting two IC chips6and7together is also exposed, which further facilitates reading the data stored in the non-volatile memory.

The present invention has been made to overcome the above disadvantages and contemplates an IC card and IC chip module with enhanced data security.

DISCLOSURE OF THE INVENTION

To achieve the above object, in one aspect of the present invention an IC card is comprised of an IC chip provided with an IC circuit, a housing body disposed to house the IC chip, and an exposure detection unit disposed to detect opened condition of the housing body, characterized in that when the exposure detection unit detects that the housing body has been opened the IC chip at least partially fails to normally operate.

As such, when the housing body housing the IC card is opened the IC circuit does not operate normally. Thus, if the IC card is improperly obtained and opened, it is extremely difficult to find the function of the IC card. Thus the IC card can obtain an enhanced data security.

Preferably the IC circuit includes a data storage unit disposed to store data wherein once the exposure detection unit detects the opened condition the data storage unit has the data at least partially rendered non-extractable.

As such, once the IC card has been opened the data storage unit has the data at least partially rendered non-extractable. Thus it is extremely difficult to obtain important data when the IC card is improperly opened.

Still preferably, the data storage unit has the data at least partially prohibited from being read once the exposure detection unit detects the opened condition.

As such, the data in the data storage unit cannot be read ones the housing body housing the IC card has been opened. The IC card may also be conveniently configured to allow the data to be read through a particular process if a party concerned does not want a third party to obtain the data but wants to keep the data.

Still preferably in the IC card the data storage unit has the data at least partially erased once the exposure detection unit detects the opened condition.

As such, once the housing body housing the IC card has been opened the data storage unit has the data at least partially erased. Thus, once the housing body has been opened no one can obtain the data. Thus the IC card can be provided with an extremely enhanced data security.

Still preferably, the IC card is comprised of a data processing unit disposed to process data wherein the data processing unit has a function at least partially stopped once the exposure detection unit detects the opened condition.

As such, the data processing unit has a function at least partially failing to function once the housing body housing the IC card has been opened. Thus, it is extremely difficult to know the function of the data processing unit if the IC card is improperly obtained and opened.

Preferably the exposure detection unit detects the opened condition by detecting external light entering when the housing body is opened.

As such, the opened condition can readily be detected, e.g., via a light receiving element arranged in the housing body.

Still preferably, as the exposure detection unit a plurality of light receiving elements are arranged in parallel.

For example, a plurality of small light-receiving elements may be arranged in the housing body to less noticeably arrange the elements. The plurality of light receiving elements can also be dispersedly arranged to detect the opened condition over a wide range of area.

Still preferably, the exposure detection unit detects the opened condition by detecting a variation in electrostatic capacitance that is introduced when the housing body is opened.

As such, the opened condition can be detected, e.g., if a capacitor defined by at least a portion of the housing body has an electrostatic capacitance varying when the housing body is opened.

Still preferably, the exposure detection unit detects the opened condition by detecting a variation in resistance that is introduced when the housing body is opened.

As such, the opened condition can be detected, e.g., if a resistor defined by at least a portion of the housing body has a value of resistance that varies when the housing body is opened.

Still preferably, the exposure detection unit detects the opened condition by detecting disconnection of a predetermined interconnection that is caused when the housing body is opened.

As such, the opened condition can be detected, e.g., if an interconnection arranged at at least a portion of the housing body is adapted to be disconnected when the housing body is opened.

In another aspect of the present invention, an IC chip module with at least two members integrally formed is comprised of an IC circuit provided at at least one of the members, characterized in that there is provided a exposure detection unit detecting opened condition of the IC chip module, wherein once the exposure detection unit detects the opened condition the IC circuit at least partially fails to normally function.

Preferably, the IC circuit includes a data storage unit disposed to store data, wherein once the exposure detection unit detects the opened condition the data storage unit has the data at least partially rendered non-extractable.

Still preferably, the data storage unit has the data at least partially prohibited from being read once the exposure detection detects the opened condition.

Still preferably, the data stored in the data storage unit is partially erased once the exposure detection unit detects the opened condition.

Still preferably, the IC circuit includes a data processing unit having a function at least partially stopped once the exposure detection unit detects the opened condition.

Still preferably, the exposure detection unit detects the opened condition by detecting external light entering when the IC chip module is opened.

Still preferably, the exposure detection unit is a plurality of light receiving elements arranged in parallel.

Still preferably, the exposure detection unit detects the opened condition by detecting a variation in electrostatic capacitance that is introduced when the IC chip module is opened.

Still preferably, the exposure detection unit detects the opened condition by detecting a variation in a value of resistance that is introduced when the IC chip module is opened.

Still preferably, the exposure detection unit detects the opened condition by detecting disconnection of a predetermined interconnection that is caused when the IC chip module is opened.

Still preferably, the exposure detection unit is at least partially defined by a portion of the IC chip circuit provided in the IC chip.

As such, the exposure detection unit is hardly recognized in the geometry of the IC chip, resulting in an enhanced data security. Furthermore, incorporating a portion or the entirety of the exposure detection unit into the IC chip in fabricating the IC chip can reduce the cost for manufacturing the IC card or the IC chip module.

Still preferably, the exposure detection unit detects the opened condition via a light receiving element detecting external light entering when the housing body is opened, wherein the light receiving element is defined by a portion of the IC circuit provided in the IC chip.

As such, a light receiving element such as a photodiode readily formed using the IC circuit, can be used to readily incorporate the exposure detection unit. It is also convenient if a plurality of small light receiving elements are dispersedly incorporated, since such light receiving elements are further hardly recognized in the geometry of the IC chip.

BEST MODES FOR CARRYING OUT THE INVENTION

First Embodiment

FIG. 1shows a configuration of an IC card30in a first embodiment of the present invention. In the figure, IC card30is a 1-coil IC card which can be used in conjunction with pre-paid cards, automatic ticket-gates of ski lifts, railroads and the like, automatic freight-sorting, and the like.

FIG. 2is a main cross section of theFIG. 1IC card30(taken along line S2—S2). IC card30has a surface member32, a core member34and a surface member36that are stacked successively. Surface members32,36are formed of synthetic resin, such as vinyl chloride, polyethylene terephthalate, (PET). Core member34is formed of synthetic resin. Surface members32,36and core member34define a housing body.

A cavity38is provided in a layer formed by core member34. In cavity38are arranged an IC chip70, a tape automated bonding (tab)40with a mounted capacitor C configuring a resonator circuit80(shown inFIG. 3), and other components. Tab40is fixed to surface member32. A joint of tab40and IC chip70is covered with a sealing agent42such as epoxy resin. An antenna82is arranged between surface member32and core member34. Antenna80and tab40are connected together via a wire44.

It should be noted that cavity38shown inFIG. 2may be filled with synthetic resin or the like. As such, the synthetic resin is also contained in the housing body described above. Furthermore, one or both of surface members32and36may be dispensed with if cavity38is filled with synthetic resin or the like.

FIG. 3is a block diagram showing a circuit configuration of IC card30and an interrogator50. Interrogator50is controlled by a control unit54to send a radio frequency (RF) carrier wave from an oscillator circuit (OSC)60via an antenna58. When IC card30approaches interrogator50, the RF carrier wave is received by IC card30antenna82. A power supply generator circuit72converts the received RF wave into a direct-current electrical power and supplies the power to other components. As such, IC card30becomes operable when it approaches interrogator50.

To transmit information from interrogator50to IC card30, control unit54controls a modulator/demodulator circuit52to modulate a RF carrier wave. In IC card30, a modulator/demodulator circuit74demodulates the modulated RF carrier wave. A CPU76as a data processing unit obtains the demodulated information and thus rewrites a content of a non-volatile memory78serving as a data storage unit, returns information, and provide other necessary operations.

On the other hand, IC card30also transmits information to interrogator50. It should be noted that IC card30does not have an oscillator circuit. Accordingly, interrogator50is adapted to send a RF carrier wave which is not modulated and IC card30is adapted to have modulator/demodulator circuit74varying an impedance of a resonator circuit80. In interrogator50, modulator/demodulator circuit52detects the impedance variation as that of resonator circuit56and demodulates it. Control unit54obtains the demodulated information and accordingly provides necessary operations.

When IC card30is moved away from interrogator50, IC card30loses its power supply and thus stops operating. However, IC card30has non-volatile memory78and can thus maintain the information stored therein if IC card30loses its power supply.

A exposure sensor84, configuring an exposure detection unit, outputs an exposure detection signal to CPU76when exposure sensor84detects that surface member32,36(shown inFIG. 2) has been removed. In response to the exposure detection signal, CPU76performs a predetermined operation, such as erasure of data stored in non-volatile memory78.

FIG. 4is a circuit diagram showing a specific example of exposure sensor84. Exposure sensor84is configured by four photodiodes D1–D4connected in parallel and a resistor R1connected in series to photodiodes D1–D4. Exposure sensor84receives a power supply voltage E from a power supply generator circuit72(shown inFIG. 3). Exposure sensor84has two output terminals Ts connected to CPU76(shown inFIG. 3).

The voltage across to output terminals Ts is set to have a value no more than a predetermined threshold when any of photodiodes D1–D4does not receive light. It is also set to have a value no less than the threshold when any of photodiodes D1–D4receives light.

Normally, as shown inFIG. 2, photodiodes D1–D4are arranged in cavity38sealed by surface members32,36and core member34. Thus the voltage across two output terminals Ts has a value no more than the threshold. When IC card30is opened, e.g. by removing surface member36, light enters cavity38and is thus received by any of photodiodes D1–D4. Thus the voltage across two output terminals Ts rises to a value no less than the threshold. The voltage created across two output terminals Ts that has a value no less than the threshold corresponds to the exposure detection signal described above.

The present example is adapted to provide a voltage across two output terminals Ts that has a value no less than a threshold when any of photodiodes D1–D4receives light. However, it may be adapted to provide a voltage across two output terminals Ts that has a value no less than the threshold when at least two, at least three or all of photodiodes D1–D4receive light, so that photodiodes D1–D4may individually have a small capacity and can thus be hardly recognized.

While in the present example four photodiodes D1–D4are arranged in parallel, any number of photodiodes may be connected in parallel. Only a single photodiode may also be used.

Furthermore, while in the present example a photodiode is used as a light detecting means, a phototransistor may be alternatively used as the light detecting means. It should be noted that the technique of detecting external light to detect the exposure is not limited to the circuit described above.

FIGS. 5A and 5Billustrate a first modification of exposure sensor84.FIG. 5Ashows a main cross section of IC card30with exposure sensor84in the first modification.FIG. 5Bis a circuit diagram of exposure sensor84.

As shown inFIG. 5B, exposure sensor84is configured of two resistors R2and R3connected in series. As is similar to the example shown inFIG. 4, exposure sensor84receives power supply voltage E from power supply generator circuit72and has two output terminals Ts connected to CPU76.

As shown inFIG. 5A, an electrode46is fixed on an internal side of surface member32and an electrode48is fixed on an internal side of surface member36. Core member34between electrodes46and48is adapted to have a predetermined electrical resistance R2. More specifically, core member34corresponds to resistor R2shown inFIG. 5B. Electrodes46and48are connected to tab40via wires62and64, respectively. Resistor R3is arranged at tab40, as appropriate (not shown).

The voltage across two output terminals Ts is set to have a value no more than a predetermined threshold when the resistance between electrodes46and48is equal to R2. It is also set to have a value no less than the threshold when the resistance between electrodes46and48exceeds R2.

Normally, electrodes46and48adhere to core member34, as shown inFIG. 5A. Thus the voltage across two output terminals Ts is no more than the threshold. However, if IC card30is opened, e.g., by removing surface member36, electrode48adhering to surface member36is removed from core member34and the resistance between electrodes46and48is thus extremely increased. Thus the voltage across two output terminals Ts exceeds the threshold. As is shown in theFIG. 4example, the voltage developed across two output terminals Ts that exceeds the threshold corresponds to the exposure detection signal described above. It should be noted that the technique of detecting a resistance variation to detect the exposure is not limited to the circuit described above.

FIGS. 6A and 6Bshow a second modification of exposure sensor84.FIG. 6Ais a main cross section of IC card30with exposure sensor84in the second modification.FIG. 6Bis a circuit diagram of exposure sensor84therein.

As shown inFIG. 6B, exposure sensor84is configured of a capacitor Cs and a resistor R4connected in series thereto. As is similar to each example above, exposure sensor84receives power supply voltage E from power supply generator circuit72and has two output terminals Ts connected to CPU76.

As shown inFIG. 6A, electrode48adheres to an internal side of surface member32and electrode48to that of surface member36. TheFIG. 6Aexample is similar to theFIG. 5example in that electrodes46and48are connected to tab40via wires62and64, respectively. It should be noted, however, that in exposure sensor84shown inFIG. 6, core member34between electrodes46and48is adapted to have a predetermined dielectric constant. More specifically, electrodes46and48and core member34configure capacitor Cs with a predetermined electrostatic capacitance Cs. Resistor R4is arranged at tab40, as appropriate (not shown).

After power supply E ON, a voltage across two output terminals Ts attains a power supply voltage according to a time constant determined by capacitor Cs and resistor R4. As such, with resistor R4set to have an appropriate value, the voltage across two output terminals Ts is set to have a value no more than a predetermined threshold for electrostatic capacitance Cs between electrodes46and48when a predetermined period of time has elapsed since power-on. It is also set to have a value no less than the threshold for an electrostatic capacitance between electrodes46and48that is smaller than Cs, e.g., for a reduced time constant when the predetermined period of time has elapsed since power-on.

Normally, electrodes46and48adhere to core member34, as shown inFIG. 6. Thus, the voltage across two output terminals Ts has a value no more than the threshold when the predetermined period of time has elapsed since power-on. However, when IC card30is opened, e.g., by removing surface member36, electrode48adhering to surface member36is removed from core member34and also moved farther away from electrode46adhering to surface member32. This results in an electrostatic capacitance smaller than Cs between electrodes46and48and hence a reduced time constant. As a result, the voltage across two output terminals Ts will have a value no less than the threshold when the predetermined period of time has elapsed since power-on. In this example, the voltage across two output terminals Ts that exceeds the threshold when the predetermined period of time has elapsed since power-on, corresponds to the exposure detection signal described above.

It should be noted that the technique of detecting a variation in electrostatic capacitance to detect the exposure is not limited to the circuit described above. For example, the exposure may be detected by detecting that variation in the resonance frequency of a resonator circuit, configured of a capacitor and a coil, which is attributed to a variation in the electrostatic capacitance of the capacitor.

It should be noted that although in each of the above embodiments, exposure sensor84is positioned external to IC chip70, as shown inFIG. 3, exposure sensor84may be positioned at any other locations. For example, as shown inFIG. 12, exposure sensor84may be positioned internal to IC chip70. Furthermore, one portion of exposure sensor84may be positioned internal to IC chip70and the other portion of exposure sensor84external to IC chip70.

Exposure sensor84partially or entirely located internal to IC chip70can be less recognizable in the geometry of IC chip70to provide a further enhanced data security. Incorporating a portion or the entirety of exposure sensor84into IC chip70in fabricating IC chip70, can also reduce the cost for manufacturing IC card30. It should also be noted that in the IC chip module described later, exposure sensor84may partially or entirely be provided internal to an IC chip, as in IC card30.

FIGS. 13A and 13Bpartially show a configuration of IC chip70when photodiodes D1–D4configuring the above-described exposure sensor84(shown inFIG. 4) are formed of a portion of an IC circuit provided in IC chip70.FIG. 13Aschematically shows a planar configuration of IC chip70.FIG. 13Bis a main cross section of IC chip70.

As shown inFIG. 13B, IC chip70has a p-type semiconductor substrate100with multiple (in this example, 4) n well regions102formed therein. Each n well region102has a p+region104. Each n well102and each p+region104configure a respective one of photodiodes D1–D4.

P+regions104are mutually connected via an aluminum interconnection108through a contact hole106aprovided in an interlayer film106. Similarly, n well regions102are mutually connected via an aluminum interconnection110(shown inFIG. 13A). As such, aluminum interconnections108and110connect four diodes D1–D4in parallel. They are covered by a passivation film112.

As has been described previously (referring toFIG. 2), when IC card30is opened, e.g., by removing surface member36, light transmitted through passivation film112and interlayer film106is received by photodiodes D1–D4formed close to a surface of IC chip70. Thus a exposure detection signal is produced.

As described above, it is technically, relatively easy to form photodiodes D1–D4of a portion of an IC circuit provided in IC chip70. Furthermore, it is convenient if such multiple small photodiodes are incorporated dispersedly, since the photodiodes are further hardly recognized in the geometry of IC chip70.

It should be noted that while theFIGS. 13A and 13Bexample shows that in p-type semiconductor substrate100a plurality of n well regions102are formed corresponding to photodiodes D1–D4, in p-type semiconductor substrate100a single, common n well region102can be provided for photodiodes D1–D4, as shown inFIGS. 14A and 14B, to conveniently reduce the length of aluminum interconnection110.

An exemplary processing executed by CPU76when IC card30is opened will now be described with reference toFIG. 3or12and theFIG. 7flow chart. As has been described above, IC card30does not have an internal power supply. As such, if IC card30is opened with CPU76not in operation, CPU76does not know that IC card30has been opened.

When a person who has opened IC card30desires to know CPU76operation, obtain non-volatile memory78data or the like and finds a pad for power supply (not shown) of exposed IC chip70and applies a probe or the like on the pad to supply power to IC chip70, then CPU76is initiated (step S1).

After it is initiated, CPU76first checks whether exposure sensor84has output the exposure detection signal (step S2). If the exposure detection signal has not been received, CPU76operates normally.

If IC card30is open, exposure sensor84has already output the exposure detection signal, as has been described above. Accordingly, CPU76erases all data stored in non-volatile memory78(step S3).

Once IC card30has been opened, the data in non-volatile memory78are all erased and no one can thus obtain the data. This can provide an extremely enhanced data security.

It should be noted that while in the present example the data in non-volatile memory78are all erased once IC card30has been opened, the data in non-volatile memory78may only partially be erased once IC card30has been opened, to conveniently, selectively erase only the data that must not be obtained by third parties while maintaining the other data.

FIG. 8is a flow chart representing another specific, exemplary processing executed by CPU76when IC card30is opened. The process until CPU76detects that IC card30has been opened (steps S11, S12) is similar to that represented in theFIG. 7example (steps S1, S2). In the present example, however, CPU76disables reading any of the data stored in non-volatile memory78once CPU76detects that IC card30has been opened (step S13).

The present example is also distinguished from theFIG. 7example in that non-volatile memory78data that have been rendered unreadable can also be re-read by applying a particular processing.

More specifically, CPU76monitors whether a predetermined pad (not shown) provided on IC chip70has received a predetermined enable signal (a read enable signal) (step S14). When the enable signal has been received, CPU76again enables reading non-volatile memory78data (step S15). Coding the enable signal can more or less prevent third parties from reading the data.

It is convenient if opening IC card30disables reading any of the data in non-volatile memory78and applying a particular processing allows the data to be obtained, since the possibility that third parties obtain the data can be reduced and the data can also be extracted later as required.

It should be noted that while in the present example, opening IC card30disables reading any of the data in non-volatile memory78, opening IC card30may alternatively only disable reading a portion of the data in non-volatile memory78.

In the above, inputting the enable signal again enables reading any of the non-volatile memory78data having been rendered unreadable. In contrast, inputting the enable signal may again only enable reading a portion of non-volatile memory78data having been rendered unreadable. This is a preferable configuration in terms of data security because no one can read the data which absolutely should not be obtained by third parties.

FIG. 9represents still another specific exemplary process provided by CPU76when IC card30is opened. The process until CPU76detects that IC card30has been opened (steps S21, S22) is similar to that in each specific example above. In the present example, however, CPU76renders itself inoperable once CPU76detects that IC card30has been opened (step S23).

Once IC card30has been opened, CPU76does not function. Thus, it is extremely difficult to find its data processing function if the IC card or IC chip module is improperly obtained and opened.

As in theFIG. 8example, in the present example also CPU76once rendered non-operable can again be operated by applying a particular processing. More specifically, CPU76can again be operated only when a predetermined pad (not shown) provided on IC chip70receives a predetermined enable signal (a CPU operation enable signal) (steps S24, S25).

In the present example, opening IC card30disables the entire function of CPU76. In contrast, opening IC card30may stop only a portion of the CPU76function while not stopping the remainder of the CPU76function. This is a convenient configuration since it can stop only the processing function(s) which should not be known to third parties while not stopping the other, general function(s).

In the present example, inputting an enable signal enables all of the functions of CPU76that have been stopped. In contrast, inputting the enable signal may again enable only a portion of the stopped CPU76functions. This is a preferable configuration in terms of data security because no one can obtain the processing function(s) which absolutely should not be known to third parties.

While the present example a stopped CPU76function is again enabled in response to a predetermined enable signal, it may be adapted to never operate again once it has been stopped.

Second Embodiment

FIG. 10Ais an exploded perspective view of an IC chip module92in a second embodiment of the present invention. IC chip module92is incorporated in an IC card used for pre-paid cards, automatic ticket-gates for ski lifts, railroads and the like, automatic freight-sorting, and the like.

IC chip module92is formed by bonding IC chips86and88to an anisotropic conductor90. In the present embodiment, a CPU, a modulator/demodulator circuit, a power supply generator circuit and other main circuits (not shown) are mounted to IC chip86, and a non-volatile memory (not shown) is mounted to IC chip88. IC chip86has an upper surface provided with a plurality of terminals86a,86b, . . . , and IC chip88has a lower surface provided with terminals88a,88b, . . . positionally opposite to terminals86a,86b. . . .

Anisotropic conductor90is an adhesive conductor which is conductive only in one direction. It may be, for example, anisolum (available from Hitachi Chemical Co., Ltd.), a thermosetting adhesive. Such anisotropic conductor90allows IC chips86and88to firmly adhere thereto to thereby electrically connect together terminals86a,86b, . . . and terminals88a,88b, . . . positionally opposite to terminals86a,86b, . . . to form IC chip module92.

Terminals86c,86d, . . . and terminals88c,88d, . . . that are electrically connected together allow electrical connection between the main circuits provided in IC chip86and the non-volatile memory provided in IC chip88. IC chip module92thus fabricated and a resonator circuit (not shown) including an antenna are sealed into a housing body (not shown) to complete a non-contact IC card.

IC chip module92includes exposure sensor84.FIG. 10Bis a circuit diagram of exposure sensor84in the present embodiment. As shown inFIG. 10B, exposure sensor84is configured by connecting an interconnection89and a resistor R5in series. Similar to each exposure sensor84described above (shown inFIG. 5B, for example), exposure sensor84receives power supply voltage E from a power supply generator circuit (not shown) provided in IC chip86and has two output terminals Ts connected to a CPU (not shown) provided in IC chip86.

The voltage across two output terminals Ts is set to have a value no more than a predetermined threshold when interconnection89allows conduction between two output terminals Ts. It is also set to have a value no less than the threshold when conduction (connection) fails between two output terminals Ts.

Normally, IC chips86and88are connected together via anisotropic conductor90and conduction is thus achieved between two output terminals Ts. Thus the voltage across two output terminals Ts is no more than the threshold. However, when IC chip module92is opened or IC chips86and88are separated from each other, conduction fails between terminals86aand86band the voltage across two output terminals Ts has a value no less than the threshold. The voltage created across two output terminals Ts that has a value no less than the threshold corresponds to the exposure detection signal described above.

It should be noted that the technique of detecting disconnection of the interconnection to detect the exposure is not limited to the circuit described above.

Furthermore, as an alternative to anisotropic conductor90, other techniques, such as soldering, a bumping technique using eutectic bonding, may be used to electrically connect terminals86a,86b, . . . and terminals88a,88b, . . . together.

Third Embodiment

FIG. 11Ais an exploded perspective view of an IC chip module98in a third embodiment of the present invention. IC chip module98includes an IC chip94and a seal member96stuck on an upper surface of IC chip94. The present embodiment differs from IC chip module92(shown inFIG. 10A) described above in that a CPU, a modulator/demodulator circuit, a power supply generator circuit and other main circuits, and a non-volatile memory are mounted to a single IC chip94.

IC chip94has an upper surface provided with two terminals94aand94band a pad95used to check a non-volatile memory. Seal member96is stuck to cover terminals94aand94band pad95. Seal member96on its adhesive side at at least that portion in a strip facing terminals94aand94b, provides a strip of interconnection97formed of a conductive material.

FIG. 11Bis a circuit diagram of exposure sensor84of IC chip module98. The circuit of exposure sensor84of the present embodiment is similar to that shown inFIG. 10B. More specifically, as shown inFIG. 11A, terminals94aand94bprovided to IC chip94are electrically connected together by the strip of interconnection97formed on seal member96.

Seal member96normally stuck on an upper surface of IC chip94allows conduction between two output terminals Ts, as in IC chip module92described above. Thus the voltage across two output terminals Ts has a value no more than a threshold. However, when IC chip module98is opened or seal member96on the upper surface of IC chip94is removed to apply a probe or the like on pad95, conduction fails between terminals94aand94band the voltage across two output terminals Ts has a value no less than the threshold. As with IC chip module92described above, the voltage created across two output terminals Ts that has a value no less than the threshold corresponds to the exposure detection signal. Receiving the exposure detection signal, the CPU is notified that IC chip module98is in opened condition.

While in theFIGS. 10A and 11Aembodiments, disconnection (non-conduction) of an interconnection is detected to detect that an IC chip module is in opened condition, external light entering when the IC chip module is opened may be detected to detect that the module is in opened condition, as is with IC card30described above. Furthermore, a variation in electrostatic capacitance introduced when the IC chip module is opened may be detected to detect that the module is in opened condition, or a variation in resistance introduced when the module is opened may be detected to detect that the module is in opened condition.

When the exposure detection signal is received, the CPU incorporated in IC chip86(shown inFIG. 10A) or94(shown inFIG. 11A) provides a processing similar to that with IC card30described above, e.g., a processing to render the CPU inoperable (FIG. 9).

It should be noted that when a CPU and a non-volatile memory are provided to a single IC chip, as in IC chip module98(shown inFIG. 11A), other types of processing can also be provided, such as erasing a portion or the entirety of the data stored in the non-volatile memory (FIG. 7), prohibiting reading a portion or the entirety of the data therein (FIG. 8).

Although in each embodiment above, the present invention is applied to a 1-coil, non-contact IC card, the present invention is also applicable to so-called multi-coil, non-contact IC cards. The present invention is also applicable to contact IC cards. Furthermore, the present invention is generally applicable to IC cards with a IC chip mounted thereto. It should be noted that an IC card referred to herein is a housing body with an IC chip housed therein and may have any shapes and sizes. The housing body includes a box-like member, as well as a generally plate-like member. The present invention is applicable not only to IC cards but also to IC chip modules including a member with an IC chip circuit.

INDUSTRIAL APPLICABILITY

Thus the present invention allows manufacturing an IC card with enhanced security and is thus advantageously applicable to any industries manufacturing and utilizing such IC card.