Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
1999-04-13
2001-01-30
Niebling, John F. (Department: 2812)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
C438S108000
Reexamination Certificate
active
06180434
ABSTRACT:
FIELD OF THE INVENTION
The present invention refers to a method of producing a contactless chip card which is supplied with energy and which communicates by means of electromagnetic waves.
1. Description of Background Art
Lately, it has become much more common to use contactless chip cards e.g. as car keys or as door keys. Such contactless chip cards permit a fast and contact-free opening of doors or also a fast identification of a specific person.
Contactless chip cards normally comprise on a chip-card substrate a microchip and an antenna structure. Normally, the chip card is not provided with an internal power supply so as to prevent the chip card from becoming ineffective when the battery has run down. The chip card is supplied with electric power in the form of electromagnetic waves from a base station, this being one reason for the fact that induction antennae or coil antennae are normally used for chip cards. In contrast to dipole antennae, loop antennae permit a more effective coupling in of electromagnetic power in the antenna on the chip. This power coupled into the antenna is rectified for supplying the microchip, which is provided on the chip card as well, with electric power so that said microchip can transmit a special code e.g. to the door lock of a car or to an identification means so as to accomplish an act coded by said code.
The operating principles of coupling electric power into the chip card and of communication between the microchip and a stationary or mobile station are known to those skilled in the art and described e.g. in U.S. Pat. No. 5,473,323. This patent describes a method for contactless data and power transmission between a stationary microstation comprising a pair of coils and a means for providing an oscillating clock signal and a mobile microunit comprising one or two coils.
In addition, U.S. Pat. No. 5,449,894 describes a method for operating a contactless chip card which is not provided with a battery and which is supplied with power via a power-transmitting alternating field from a write/read unit. The bidirectional data transmission is accomplished by modulation of the power-transmitting alternating field by means of an antenna coil, said power-transmitting field producing a coil current in the coil and a coil voltage at the coil; an input circuit is coupled to ends of the coil for generating a supply voltage from the current in the coil and a voltage detector is coupled to the ends of the coil for detecting specific properties of the power-transmitting alternating field.
U.S. Pat. No. 5,440,302 describes a device for contactless data and power transmission, which comprises a stationary part and a mobile part.
2. Description of Prior Art
For producing contactless chip cards, an insulating chip-card substrate is normally used on which a microchip that is capable of carrying out the desired functions is placed. At a point of the chip-card substrate which is remote from the microchip or on a separate substrate, the necessary antenna structures, which are substantially implemented as coils, are additionally applied e.g. by means of known photolithograhic techniques. For connecting the coil structures to the microchip, bonding wires can be used in the case of known contactless chip cards. The bonding wires extend from a connection point of a coil to a connection point on the microchip, said bonding wires being produced in the manner known by means of a bonding device so as to interconnect the coil structure and the microchip in an electrically conductive manner.
This method of producing known contactless chip cards is disadvantageous insofar as expensive bonding devices are required for connecting the microchip to the antenna structure. In the case of a mass product, and a contactless chip card is such a mass product beyond all doubt, even small cost advantages of the product decide whether said product will gain acceptance in comparison with a more expensive competing product.
EP 0756244 A2, which has been published after the priority date of the present application, discloses a circuit module and a method of producing a circuit module. For embedding an integrated circuit into a supporting substrate, a suitable recess can either be provided or the integrated circuit can be pressed into the supporting substrate by applying heat and pressure.
DE 4416697 A1 discloses a data carrier provided with an integrated circuit. The integrated circuit is connected to at least one coil via contact elements, said integrated circuit and said contact elements forming a module and the coil being arranged on a card body. The coil is arranged on an inner layer of the card body, said inner layer being also provided with an opening for receiving the module therein. The module, which comprises at least one integrated circuit with two connections, is introduced in a previously produced recess of the inner layer.
DE 4431606 A1 discloses a chip-card module for a contactless chip card and a method of producing the same. A semiconductor chip is arranged on a flexible, non-conductive supporting chip, two ends of an enamelled-wire coil being electrically connected to the semiconductor chip so as to establish a direct connection between said semiconductor chip and the coil ends. The chip is placed on the carrier body and is then contacted.
DE 44 10 732 A1 discloses both a method of producing a chip card and a chip card. The chip card comprises a chip and a coil, said chip and said coil being arranged on a common substrate and the coil being formed by laying a coil wire. The chip is incorporated into the surface of the substrate by thermocompression, i.e. by making the surface of the substrate soft by means of heat and by pressing the chip into said surface, or by “rubbing in” by means of ultrasonic action.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide an economy-priced and reliable method of producing a contactless chip card.
This object is achieved by a method of producing a contactless chip card, comprising the steps of: holding a chip, which is provided with terminal pads on a surface thereof, in a mould defining a chip-card substrate, in such a way that the chip surface provided with said terminal pads is located substantially in the same plane as a chip-card substrate surface defined by the mould; introducing a chip-card substrate material into the mould; and applying a coil structure by screen-printing a conductive paste onto the chip-card substrate in such a way that the coil structure extends up to the terminal pads on the chip.
The present invention is based on the finding that the connection of the coil structure to the microchip, which has to be carried out in a separate step, can be dispensed with, when a coil structure as well as a chip are arranged on a common insulating chip-card substrate. By realizing the coil structure by the application of a conductive paste, after arranging the chip on the chip-card substrate, in such a way that the coil structure extends up to the terminal pads on the chip, it is no longer necessary to carry out a separate bonding step, since the coil structure is already connected to the chip.
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patent: 5969415 (1999-10-01), Pranez
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patent: 6031278 (2000-02-01), Onoda et al.
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patent: 6093584 (2000-07-01), Fjelstad
Azdasht Ghassem
Lange Martin
Glenn Michael A.
Gurley Lynne A.
Niebling John F.
Zakel Elke
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