The invention generally relates to an encapsulated chip and specifically to an encapsulated transponder chip in a smart label.
The cost of producing integrated circuits has fallen considerably in the past few years. As a consequence, a considerable range of new application fields has opened up for integrated circuits. Examples of this are the so-called smart labels for marking goods and for the identification of goods. Smart labels consist of a transponder chip in which the product-relevant information is stored, and an aerial to couple it to a reading device, which enables non-contact reading of the data stored in the transponder chip.
In the case of many smart labels, the transponder chip is built onto a base substrate that surrounds the aerial in the form of a conductive layer. The aerial is connected to the transponder chip. For these applications, the chips may be packed into a housing of, for example, plastic, or they may be directly built onto the base substrate, for example by means of flip-chip technology.
The invention provides a new type of encapsulated chip, particularly suitable for smart label applications, which has a housing-that may be of flexible construction and which, at the same time, facilitates external contacting of the chip, and which can be produced by a simple and cost-effective process, whereby the chip is exposed to very little mechanical stress during the production process of the housing.
According to an embodiment of the invention, the chip is built onto a baseplate, on which the chip is located in such a way that its contact surfaces face away from the baseplate, where a layer of conductive material arranged around the chip is applied to the baseplate, which serves to connect the chip, is at least exactly as high as the chip, and functions as support for a cover plate arranged on the layer, one side of which, opposed to the chip, being provided with conductive surfaces that are arranged in such a way as to form a connection between the chip and the layer.
The chip according to and embodiment of the invention is of particularly simple construction that makes possible a cost-effective production process, consisting of only a few process steps, which is of particular importance when mass products, such as smart labels, are to be manufactured. The cover plate fulfils a dual function in this case. It allows the encapsulation of the chip and, at the same time, the establishment of electrical contact between the chip and the conductive layer that may consist, for example, of a transponder aerial. The chip is also mechanically stress-relieved in that the conductive layer is at least as high as the chip, or higher than the chip. This fact is particularly useful when the chip is integrated in a smart label.
The requirement of the invention is met, according to the invention, by several processes for the manufacture of encapsulated chips.
According to a first method for the manufacture of an encapsulated chip according to the invention, the chip is attached to a baseplate in such a way that its contact surfaces face away from the baseplate, and a conductive layer, that serves to connect the chip and that is at least as high as the chip, is applied around the chip onto the baseplate. Furthermore, a cover plate is provided where on one of its sides one or more conductive surfaces are arranged in such a way that they can form a connection between the chip and the layer. An anisotropically conductive film is then applied to one side of the cover plate and the cover plate is then aligned over the baseplate so that the side with the conductive surface or the conductive surfaces, respectively, is arranged over the chip so as to enable a connection between the chip and the layer to be formed. The cover plate is finally pressed onto the layer, under application of heat, in such a way that the anisotropically conductive film forms a mechanical and an electrical connection between the contact surfaces of the chip and the conductive surface or the conductive surfaces, respectively, of the cover plate and, at the same time, an electrical and a mechanical connection between the conductive surface or the conductive surfaces, respectively, of the cover plate and the layer.
According to a second method for the manufacture of an encapsulated chip according to the invention, a conductive layer which serves to connect the chip and that is at least as high as the chip itself, is applied to a baseplate around an area intended for the chip. Then one or more conductive surfaces are arranged on one side of a cover plate in such a way that they can form a connection between the chip and the layer, and an anisotropically conductive film is applied over the conductive film on one side of the cover plate. The chip is then positioned on the anisotropically conductive film so that its contact surfaces point towards the cover plate, and the cover plate is positioned on the baseplate in such a way that the chip comes to rest on the surface area intended for it and a connection between the chip and the layer can be formed. The cover plate is finally pressed onto the layer, under application of heat, in such a way that the anisotropically conductive film forms a mechanical and an electrical connection between the contact surfaces of the chip and the conductive surface or the conductive surfaces, respectively, of the cover plate and, at the same time, an electrical and a mechanical connection between the conductive surface or the conductive surfaces, respectively, of the cover plate and the layer.
Advantageous further developments of the invention are characterized in the sub-claims.
The invention shall now be explained in exemplified form with reference to the drawing, where
a to 3g sectional side views of the parts of an encapsulated chip produced during the individual manufacturing stages in a first procedure according to the invention for the production of an encapsulated chip, and
a to 4g sectional side views of the parts of an encapsulated chip produced during the individual manufacturing stages in a second procedure according to the invention for the production of an encapsulated chip.
An electrically conductive layer 14 that can consist of, for example, aluminum or copper, is applied to the baseplate 12. This layer 14 serves to connect the chip 10 to other component parts arranged on the baseplate 12, which are not represented in the
The chip 10 is surrounded by filling material 26. This may consist, for example, of two different glues: A conductive glue that is applied to the contact surfaces 20 and which connects the conductive surfaces 18 of the cover plate 16 with the contact surfaces 20 of the chip 10, as well as a non-conductive glue that surrounds the chip 10. In order to establish an electrical connection between the contact surfaces 20 of the chip and the conductive surfaces 18 of the cover plate 16, an anisotropically conductive film (ACF) can also be used, that is a material that has a very low electrical resistance in only one direction whilst it is virtually non-conductive in the direction perpendicular to the other. The anisotropically conductive film 26 may consist, for example, of an epoxy resin containing a very large number of electrically conductive particles, which are-arranged so as to touch each other only along the direction in which electrical conductivity is desired. The epoxy resin also serves as the filling material that fully encloses the chip 10 and protects it from external influences, such as touch contact or humidity.
The conductive layer 14 on the baseplate 12 can be contact-bonded to the conductive surfaces 18 of the cover plate 16 by purely mechanical means, such as by crimping. The electrical connection can also be achieved by means of an electrically conductive glue or an anisotropically conductive film.
The transponder chip 30, together with the aerial and the casing, can be embodied as a so-called smart label, where, for example, in the memory of the transponder chip 30, information is stored that represents the characteristics of an object to which the smart label is attached. Several of these smart labels may, for example, be attached to a paper strip, which then may be coiled up for compact transport and easy handling of the smart labels. In the case of these coiled rolls, which may contain thousands of coiled-up smart labels, enormous pressure is exerted on some of the individual smart labels and, in consequence, on the delicate transponder chips 30. The transponder chips 30 are well able to resist this pressure, since they are pressure-relieved by the conductive surfaces 14 that are as high or higher than the transponder chips 30, and occupy a relatively large surface area as compared with the transponder chip.
A procedure according to the invention for the manufacture of an encapsulated chip 10 shall be explained in the following, with reference to the
As can be appreciated in
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Then, as may be appreciated in
In the last step, as shown in
A second procedure according to the invention for the manufacture of an encapsulated chip is represented in the
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Procedures for the manufacture of an encapsulated chip 10, which may be modified in a plurality of ways, have been described by giving two concrete examples. The anisotropically conductive film 26 may be applied, for example, to only a smaller surface, whereby the conductive layer 14 and parts of the conductive surfaces 18 will not be covered. Then, before pressing the cover plate 16 onto the baseplate 12, the conductive layer 14 on the baseplate 12 and the conductive surfaces 18 on the cover plate 16 can be connected by crimping. The crimping connection can be achieved, for example, by a mechanical deformation process or by means of ultrasound. The connection can, of course, also be made by means of the anisotropically conductive film.
Number | Date | Country | Kind |
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102 35 771.4 | Aug 2002 | DE | national |
Number | Date | Country | |
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Parent | 10629095 | Jul 2003 | US |
Child | 11025245 | Dec 2004 | US |