SE2151631A1

SE2151631A1 - Method and apparatus for producing a radio-frequency identification (rfid) transponder

Info

Publication number: SE2151631A1
Application number: SE2151631A
Authority: SE
Inventors: Eerik Halonen; Juha Ikonen; Lauri Huhtasalo
Original assignee: Digital Tags Finland Oy
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2021-12-28
Also published as: WO2020240252A1; FI20216339A1; SE545307C2

Abstract

A method for producing radio-frequency identification (RFID) transponders arranged on a carrying substrate is disclosed, comprising: providing two substrate areas, each having at least one antenna element with antenna terminals arranged thereon; and providing a dual-sided integrated circuit (IC) having an antenna contact on each of two opposed external surfaces. The IC is arranged on one of the substrate areas, so that one of the antenna contacts comes in mechanical contact with one of the antenna terminals. The two substrate areas are then brought together, thereby bringing the second antenna contact in mechanical contact with second antenna terminal. Finally, heat is applied to the substrate areas in the vicinity of the IC, heating it to a temperature at least equal to a characteristic melting point of the antenna terminals, thereby forming electric contact between the antenna contacts and the antenna terminals. A corresponding apparatus is also disclosed.

Description

METHOD AND APPARATUS FOR PRODUCING A RADIO-FREQUENCYIDENTIFICATION (RFID) TRANSPONDER Technical ﬁeld of the invention The present invention is related to a method and apparatus forproduction of a radio-frequency identification (RFID) transponder arranged ona carrying substrate.

BackgroundRFID transponders used for a wide variety of purposes, such as for inventory, locate, identify, authenticate, configure, enable/disable and monitoritems to which the tags are attached or in which the tags are embedded.RFID systems may be used in retail applications to inventory and track items,in consumer- and industrial-electronics applications to configure and monitoritems, in security applications to prevent loss or theft of items, in anti-counterfeiting applications to ensure item authenticity, and in many, manyother applications.

In conventional RFID transponders, the integrated circuit (IC) isprovided with 2 to 4 bumps or pads at their bottom side. These pads orbumps are to be connected to the leads of the conductive antenna pattern.There is generally an increasing demand for smaller RFID transponders, andalso an increasing demand for less costly RFID transponders. The RFIDmicrochip is a major cost factor of the transponder, and the microchip cost isproportional to its size, and consequently there is also a need for smallerRFID microchips (IC:s). However, as the size of the IC's decreases, theassembly of the transponder, and in particular the placement of the IC to anantenna pattern, becomes more complicated, tedious and costly. Typically,the bumps or pads may have a size of about 50 or 60 microns, and theseparation gap is typically 0.10-0.20 mm. The connection areas on theantenna conductor need to be equally closely arranged, and acceptabletolerances during manufacturing are extremely low.

Thus, the only available possibility to produce RFID transponders atrelatively low cost is to use rather large lC:s, thereby enabling a relatively longseparation between the bumps/pads, and thus enabling placement of the lC:son the antenna pattern with somewhat less precision and with highertolerances.

Also, if smaller lC:s are used, the gap between the connection areas ofthe antenna also needs to get smaller and this is very difficult and costly toachieve with current etching technology.

These strict requirements, in particular when relatively small lC:s areused, makes it necessary to use highly engineered and specializedautomation equipment, which increases the overall production cost. Also, dueto the strict requirements and low tolerances, it is difficult to obtain a highthroughput, i.e. high UPH (Units Per Hour).

The only solution to this so far has been to use larger lC:s, but thematerial cost is correlated to the size, the cost savings with this approach arevery limited. Further, for many applications there is a strong need for verysmall RFID transponders.

An alternative solution has been suggested in US 2014/0144992 andUS 9489611. These documents disclose a solution where dual-sided lC:s areused, having a contact pad/bump on two different sides. Hereby, the antennamay be connected to the IC on two different sides. This solution reduces thetolerance problems, and enables use of smaller lC:s with relatively highalignment and attachment tolerances. On the other hand, the connection ofthe IC contacts to the antenna structure hereby become very complicated,and the production complexity and production costs are still very high.

There is therefore a need for a method and apparatus enablingproduction of RFID transponders in a less complex, faster and more cost-effective way.

Summarylt is therefore an object of the present invention to provide a method and an apparatus for producing RFID transponders arranged on a carrying substrate, such as RFID tags or labels, or intelligent packaging products,which at least alleviates the above-discussed problems.

This object is obtained by means of a method and an apparatus inaccordance with the appended claims.

According to a first aspect of the invention there is provided a methodfor producing radio-frequency identification (RFID) transponders arranged ona carrying substrate, comprising: providing a first substrate area and a second substrate area, the firstand second substrate areas each having at least one antenna elementformed by an electrically conductive pattern arranged thereon, and preferablyseveral antenna elements arranged sequentially thereon along a longitudinalextension of the first and second substrate areas, wherein a first antennaelement arranged on the first substrate area has a first antenna terminal, anda second antenna element arranged on the second substrate area has asecond antenna terminal; providing a dual-sided integrated circuit (IC) including a first circuitblock electrically coupled to a first antenna contact, disposed on a firstexternal surface of the IC, and a second antenna contact, disposed on asecond external surface of the IC opposite the first external surface of the IC; arranging the IC on the first substrate area, whereby the first antennacontact comes in mechanical contact with the first antenna terminal; bringing the first substrate area and the second substrate areatogether, thereby bringing the second antenna contact in mechanical contactwith the second antenna terminal; heating the first and second substrate areas in the vicinity of the IC to atemperature at least equal to a characteristic melting point of said first andsecond antenna terminals, thereby forming electric contact between the firstantenna contact and the first antenna terminal, and between the secondantenna contact and the second antenna terminal.

Electrically connecting the antenna contacts and the antenna terminalsresults in the antenna elements becoming electrically and operativelyconnected to the integrated circuit that is electrically connected to the contact pad. By "operatively connected" is here meant that the antenna element isoperable as an antenna for the integrated circuit.

By the "characteristic melting point" is here meant the temperature atwhich the material in question begins to behave as a more or less viscousliquid. lf the material starts to melt at a well-defined temperature, then thattemperature is the characteristic melting point. lf the material is a compositewhere two or more constituents remain separate in different particles and/oreven within a single particle, the characteristic melting point is thetemperature at which such a constituent melt that has a predominant effect onthe creation of cohesion within the melt coming from a plurality of moltenparticles. lf the conductive material is homogeneous in composition andconsist only of one metal or alloy that has a well-defined melting temperature,the characteristic melting point is the melting temperature of that metal oralloy. The characteristic melting point should preferably be low enough so thatthe integrated circuit and the first and second substrates are not damagedduring the heating. Typically, the characteristic melting point is less than 300°C, and preferably less than 200 °C, for example in the range from 100 °C to200 °C.

The antenna terminals contact can be made of an alloy comprising tinand bismuth. Such materials can be melted and cured quickly and often havecharacteristic melting points that are particularly suitable for the presentinvenﬁon. ln accordance with one embodiment, the other parts of the antennaelements are also made of a material having a melting point at or below saidcharacteristic melting point. For example, the antenna elements can also bemade of an alloy comprising tin and bismuth. Hereby, the soldering togetherof the antenna terminals and the antenna contacts becomes even quicker andeasier.

Thus, the heating of the conductive material to a temperatureexceeding a characteristic melting temperature of the conductive materialresults in a melting and solidification of the conductive material. This may initself be sufficient to form the contact. However, the method may alsocomprise a step of applying a pressure onto the heated conductive material.

This pressure is preferably applied relatively soon after the heating, so thatthe material still remains in a melted or almost melted state. Hereby, a goodadhesion and good continuity of conductivity will be ensured.

It should be noted that the entire contact terminal(s) is not necessarilyheated to a temperature at least equal to the characteristic melting point. ltmay be that only a portion of the contact terminal(s) is heated to such atemperature.

The present invention is based on the realization that dual-sidedintegrated circuits (lCs) including antenna contacts arranged on oppositesurfaces allow connection to antenna elements in a very fast and reliableway, and with significantly reduced need for placement accuracy. This alsoenables use of very small sized lCs, and with significantly lower need forantenna gap resolution. It has further been found that this type of lCs issurprisingly well suited for production and assembling with a heat-inducedattachment process. This process can e.g. be a sheet-to-sheet process, butmay also be performed as a roll-to-roll process. This makes production veryfast, and dramatically increases the throughput. At the same time, theassembly machine can be made simpler and less costly. Overall, this enablesproduction of very small RFID tags and labels to a very low cost.

A factor that contributes to the speed and simplicity of the method isthat the step of operatively connecting the antenna elements to the IC can beperformed with relatively low precision, acceptable tolerances typically beingin the range of 10.5 mm. By comparison, mounting the IC to the antenna in aconventional way must usually be done with very high precision, typically withtolerance requirements of about +/- 50 microns.

The method is easy to integrate with many existing productions lines,especially production lines for producing packaging products because of theequipment typically used in such production lines. Further, since the RFID lCsmay now be connected to the antenna elements close to and just beforeapplication of labels/tags to e.g. a package, or in the formation of a product,the package or product producer obtains greater control of the process. Thus,the method and apparatus of the present invention can e.g. be arranged asan integral part of a packing line, converting line or even into die cutting units.

The production of the antenna elements also becomes faster, simplerand less costly, since relatively large and coarse antenna terminals may beused. The antenna elements can also be produced directly on e.g. apackaging material, whereby no extra layers and the like is needed, incontrast to in current label-based delivery formats.

The connecting of the lCs to the antenna elements in this way is alsovery fast. A connection in the time scale of ms can be achieved, such as inthe range of <1 s, and in particular in the range 1-500 ms, whereas currentlyused boding times are typically in the range 7-9 s.

The mounting and connection of the lCs to the antenna elements isalso made without e.g. the need to flip the lC:s, as in currently used flip-chipprocesses, and there is no need for thermo-compression curing and the like.

The first substrate area may be provided on a first substrate, and thesecond substrate area may be provided on a separate second substrate.However, alternatively, the first and second substrate areas may be providedon the same substrate, wherein the substrate may be folded to bring the firstsubstrate area and the second substrate area together.

The one or more substrate(s) may be provided in the forms of sheetsand/or webs, and may e.g. be provided in the form of a roll of substrate web.

The method may e.g. be a roll-to roll process, in which input rolls areprovided at one end and output rolls are received at the other. Hereby, theprocess is highly suitable for fully automated production. ln such a process,the method/apparatus also preferably comprises re-winding of the assembledweb on an output roll, at a re-winding station.

The roll-to-roll process is highly suitable for production of RFIDtransponders arranged on a carrying substrate forming RFID labels or RFIDtags.

Alternatively, the substrate(s) may form a packaging material, andwherein the RFID transponders arranged on a carrying substrate forms apackaging blank for an intelligent packaging product. This can also be madein a roll-to-roll process, but may alternatively be made in a sheet-to-sheetprocess or in a roll-to-sheet process. Thus, for production of intelligentpackaging products, the antenna elements may be provided directly on a package material, in the form of a sheet or a web, and the lCs may beconnected to the antenna elements e.g. in a packaging converting facility.Hereby, packaging blanks for use as intelligent packages, and with integratedRFID transponders, can be produced in a very efficient way.

The heating may be applied be means of a contactless heatingtechnique. Using such a technique helps to reduce the risk of the antennaelement and/or the contact pads becoming smeared out. Also, suchtechniques typically allow for the heating step to be performed with relativelylow precision, thus helping to make this step simple and fast.

The method may comprise pressing the heated antenna elements, andin particular the antenna terminals, and the corresponding antenna contactsagainst each other. This may further strengthen the mechanical connectionbetween the antenna element and the contacts. The antenna terminals maybe pressed against the corresponding antenna contacts simultaneously withthe heating, and/or after the heating. The pressure may be applied by a nip.ln case heating and pressing should occur simultaneously, the nip may havea surface temperature at or above the characteristic melting point. lf pressureis applied after heating, as a separate step, the surface temperature of the nipis preferably lower than the characteristic melting point.

An adhesive may be arranged on at least one of the first and secondsubstrate areas, the adhesive being arranged to adhere the first and secondsubstrate areas together after the first and second substrate areas have beenbrought in mechanical contact. The adhesive helps to create a strongattachment between the first and second substrate areas. The adhesive mayalso act as dielectric material between the conductor pattern/antenna elementbelow the IC and conductor pattern/antenna element above the IC, and willconsequently also serve the purpose of preventing short-circuiting of thoseantenna elements/conductor patterns. A lamination nip may also be used toapply pressure onto the assembled substrate, to provide an even betterlamination.

The one or more substrate(s) can be made of at least one of: paper,board, polymer film, textile and non-woven material. ln particular, thesubstrate(s) can be made of paper. Thereby, the RFID transponders become particularly suitable for attachment to objects made of paper materials, suchas boxes for packaging.

The RFID transponders may be either passive, i.e. powered by areader's electromagnetic field, or active, i.e. powered by an onboard battery.

The antenna elements may be produced in various ways. For example,the forming of the conductive pattern can be made by printing with conductiveink, such as silver ink, i.e. ink comprising conductive silver particles, orparticles of carbon, copper, graphene, etc. The ink may also comprise two ormore different materials, such as particles of different materials, or particlescomprising two or more materials. ln particular, the ink may comprise amaterial having a characteristic melting point being similar, identical or belowthe characteristic melting point of the contact pads. The solvent can beevaporated by means of heating at an elevated temperature, by use ofphotonic curing, or the like. The forming of the conductive pattern can also bemade by first providing a conductive layer on the substrate, and the removingor forming this conductive layer into the desired conductive pattern, e.g. bymeans of grinding, cutting, or the like. This can e.g. be made in the waydisclosed in EP 1 665 912 and WO 2005/027599, said documents herebybeing incorporated in their entirety by reference. ln order for such antennaelements to connect to the IC during heating, it is preferred that at least theink used to form the antenna terminals is thermoplastic, and has a relativelylow characteristic melting point, such as below 300 deg. C, to reduce the riskof damage to the lC:s due to the heat. ln one embodiment, the forming of conductive material in a patterncomprise: transferring a conductive material in a pattern corresponding tosaid electrically conductive pattern to a surface of the substrate; and heatingthe conductive material to a temperature exceeding a characteristic meltingtemperature of the conductive material.

The conductive material is preferably in the form of electricallyconductive solid particles. The transferring of conductive material to thesubstrate surface may e.g. comprise direct printing of electrically conductiveparticles as a part of a compound that contains, in addition of the electricallyconductive solid particles, a fluid or gelatinous substance. However, the electrically conductive solid particles may also be in the form of dry powder.Further, an adhesive area may be created on the surface of the substrateprior to transfer of the particles.

The transfer of the conductive particles and the curing and solidificationmay in particular be made in the way disclosed in one or several of WO2013/113995, WO 2009/135985, WO 2008/006941 and WO 2016/189446, allof said documents hereby being incorporated in their entirety by reference.

Curing may be effected by heating, or by a combination of heat andpressure. ln case both heat and pressure are used, the curing may bereferred to as sintering. During curing, the transferred conductive material,e.g. in the form of particles, is converted into a continuously conductingpattern affixed to the web substrate. The sintering is preferably carried out ina nip comprising two opposing nip members, at least one of which may beheatable, between which the web is fed. Additionally, or alternatively, thecuring may also comprise irradiation of the conductive material, e.g. with UVradiation, e-beam radiation or the like.

The two antenna elements arranged on the two substrate areas maybe identical or symmetrical to each other. Preferably, the two antennaelements have essentially the same size and coverage area. However,alternatively, one of the antenna elements is larger than the other. The twoantenna elements, when electrically connected to the IC, together form anantenna for the RFID transponder, wherein the first antenna element formsX% of the antenna and the second antenna element forms 100-X% of theantenna, where X > 0. X may here be 50, whereby the two antenna elementshave the same size, but X may also be any number between 1-and 99, suchas between 25 and 50.

The dual-sided ICs can e.g. be made and designed in accordance withthe disclosures of US 9489611 and US 2014/0144992, said documentshereby incorporated in their entirety by reference. The internal wirings of themicrochip are designed so that the IC has one antenna contact at one side,and another antenna contact at the other.

The antenna contacts on the IC are preferably relatively large, in termsof the size of the IC. For example, at least one of the first antenna contact and the second antenna contact may include a conductive pad spanningsubstantially an entirety of the first external surface or the second externalsurface of the IC, respectively. However, a bump of smaller length and widthdimensions may also be used, on one or both sides of the IC. Thus, the ICcan be provided with a bump on each of the two opposing sides, or with a padon each of the two opposing sides, or with a bump on one side and a pad onthe other. The bumps/pads could be made of any commonly used material,such as gold, aluminum or copper.

The invention is inter alia based on the surprising realization of thepresent inventors that a label converting process is in many aspects similar tomethods for producing printed electronics. Thus, by means of the presentinvention, an electrically conductive pattern, forming the antenna elements forthe RFID transponder, can be formed as an integral part of a conventionallabel converting process. This enables the production of labels with integratedelectrically conductive patterns in a much faster and more cost-efficient way.lt also enables enhanced control of the entire process, since it is all made atonce, and in a single production line. There is therefore no longer a need toform the electrically conductive patterns separately, and also no need for thedifficult and cumbersome process of connecting the electrically conductivepatterns onto already produced labels. The same process may also comprise,as an integrated step, the arrangement and connection of the integratedcircuit, i.e. the RFID chip. Hereby, many steps that are conventionallyperformed separately in each of these processes, such as insertion of webrolls, threading of webs through the production path, re-winding, etc, canhereby be performed only once, which makes the process much more costand time efficient. lt also reduces the overall need for manufacturingmachinery and production space.

According to another aspect of the invention, there is provided anapparatus for producing a radio-frequency identification transponder on acarrying substrate, comprising: an input station to receive one or more substrate, the substrate(s)having a first substrate area and a second substrate area, the first andsecond substrate areas each having at least one antenna element formed by 11 an electrically conductive pattern arranged thereon, and preferably severalantenna elements arranged sequentially thereon along a longitudinalextension of the first and second substrate areas, wherein a first antennaelement arranged on the first substrate area has a first antenna terminal, anda second antenna element arranged on the second substrate area has asecond antenna terminal; a placement device arranged to place a dual-sided integrated circuit(IC) on the first substrate area, the IC including a first circuit block electricallycoupled to a first antenna contact, disposed on a first external surface of theIC, and a second antenna contact, disposed on a second external surface ofthe IC opposite the first external surface of the IC, and wherein the IC isplaced on the first substrate area in such a way that the first antenna contactcomes in mechanical contact with the first antenna terminal; a transfer device configured to bring the first substrate area and thesecond substrate area together, thereby bringing the second antenna contactin mechanical contact with the second antenna terminal; a heating device configured to heat the first and second substrateareas in the vicinity of the IC to a temperature at least equal to acharacteristic melting point of said first and second antenna terminals,thereby forming electric contact between the first antenna contact and the firstantenna terminal, and between the second antenna contact and the secondantenna terminal.

By this aspect of the invention, similar advantages and preferredfeatures and embodiments as discussed above, in relation to the first aspectof the invention, are obtainable.

The apparatus may be realized based on a conventional labelconverting machine, but with added equipment and stations to form theelectrically conductive pattern, and for connecting an integrated circuit, suchas an RFID chip, to the electrically conductive pattern.

As discussed above, the forming of the conductive pattern can bemade in various ways. According to one embodiment, the pattern formingstation comprises a particle handler for transferring a conductive material in apattern corresponding to the electrically conductive pattern to a surface of the 12 face material web; and a heater for heating the conductive material to atemperature exceeding a characteristic melting temperature of the conductivematerial.

The apparatus may further comprise a pressing device arranged topress the first and second substrate areas against each other over the IC.The pressure may e.g. be applied by a nip, wherein the surface temperatureof the nip may be lower than said characteristic melting point.

The apparatus may further comprise an adhesive applicator, arrangedto provide an adhesive on at least one of the first and second substrate areas,the adhesive being arranged to adhere the first and second substrate areastogether after the first and second substrate areas have been brought inmechanical contact.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

Brief description of the drawinqs For exemplifying purposes, the invention will be described in closerdetail in the following with reference to embodiments thereof illustrated in theattached drawings, wherein: Fig 1 is a schematic illustration of a production line for producing RFIDlabels or RFID tags in accordance a method and apparatus of an embodimentof the present invention; Fig 2 is a schematic illustration of a production line for producing RFIDlabels or RFID tags in accordance with another embodiment of the presentinvention; Fig 3 is a schematic illustration of a production line for producing RFIDlabels or RFID tags in accordance with still another embodiment of thepresent invention; Fig 4a-c are schematic illustrations of RFID transponders producible bythe present invention, where Fig 4a illustrate top views of two substrate websprovided with complementary antenna elements, Fig 4b illustrate a top view ofthe antenna elements of Fig 4a assembled together with lC:s, where the 13 substrate webs are shown as fully transparent, and Fig 4c is a side view ofone of the transponders in Fig 4b; Fig 5 is a schematic illustration of a substrate web provided with twocomplementary antenna elements, intended to be folded over each other toform the antenna; Fig 6 is a schematic illustration of second embodiment of a foldablesubstrate web; Fig 7 is a schematic illustration of third embodiment of a foldablesubstrate web; Fig 8 is a schematic illustration of fourth embodiment of a foldablesubstrate web; and Fig. 9a and b are schematic illustrations of a production line forproducing RFID labels or RFID tags in accordance with yet another embodiment of the present invention.

Detailed description of preferred embodiments ln the following detailed description preferred embodiments of theinvention will be described. However, it is to be understood that features ofthe different embodiments are exchangeable between the embodiments andmay be combined in different ways, unless anything else is specificallyindicated. It may also be noted that, for the sake of clarity, the dimensions ofcertain components illustrated in the drawings may differ from thecorresponding dimensions in real-life implementations of the invention, suchas the thickness of various layers, etc. Further, the invention will in thefollowing primarily be exemplified in relation to a roll-to-roll process, where thesubstrates are provided in the form of webs arranged on rolls. However, it isto be appreciated by the skilled reader, that the process may also be used forsubstrates of other types, such as sheets. Thus, the process may also beembodied as a sheet-to-sheet process or a roll-to-sheet process.

With reference to Fig 1, a production method and apparatus for formingRFID transponders, such as RFID labels or tags, will now be discussed inmore detail. 14 The system 100 comprises a first input or unwind station 101a,provided with a reel holder for receiving rolls 102a of a substrate web 200a.The substrate web can e.g. be paper.

The substrate material is preferably a fibrous web, and can be of any ofa wide variety of materials, widths and thicknesses. Paper and polymer films(plastics) are suitable, but other similar non-conductive surfaces may be alsoused. The substrate material may also be coated, and a multilayered webmay also be used.

The substrate web is transferred to a particle handler 103a, arrangedto transfer a conductive material in a pattern onto a surface of the substrateweb. The pattern corresponds to the electrically conductive pattern of one ofthe antenna elements to be provided in the RFID transponder.

Prior to the particle transfer, an adhesion area may be formed in thesurface of the web, as is per se known in the art, in order to maintain theparticles in the desired place until melting and pressing has occurred.However, depending on the materials used, etc, this step may also beomitted. The adhesion area may be formed in correspondence with theintended pattern for the electrically conductive pattern to be formed, and maye.g. be formed by dispersive adhesion (i.e. gluing) or electrostatic adhesion.This may e.g. be performed by an adhesive printing or lacquering section (notseparately shown) that is configured to spread an adhesive or lacquer ontothe substrate to create an adhesion area of predetermined form, or by anelectric charger section that is configured to create a spatial distribution ofstatic electric charge in the web material to create an adhesion area ofpredetermined form. However, additionally or alternatively, the particles maydirectly be transferred onto the web in correspondence with the electricallyconductive pattern to be formed. lt is also possible to transfer electrically conductive solid particles ontothe surface of the substrate with a method that involves simultaneouslycreating the necessary adhesion. For example, the electrically conductivesolid particles may come as a part of a compound that contains, in addition tothe electrically conductive solid particles, a fluid or gelatinous substance that has adhesive properties. ln that case, the preparatory creation of adhesionareas may be omitted.

The conductive material is then cured to form a solidified, morecompact pattern. This can e.g. be made by application of heat with a heater104a. Hereby, the conductive material is preferably heated to a temperatureexceeding a characteristic melting temperature of the conductive material.

The heating is preferably a non-contacting heating, which reduces therisk of smearing or unwanted macroscopic changes in the spatial distributionof conductive material on the surface of the web. However, heating methodsthat are contacting may also be used. Especially if heating is made with lowor very low contact pressure, it may well have the same advantageous non-smearing characteristics. As a result of the heating, a melt is created.

Non-contacting heating may e.g. be obtained by infrared radiation,laser heating, or heating with other types of radiation, inductive heating,streaming with hot gas, etc. However, heating may also be made by bringingthe substrate web or the conductive material into contact with a heated body,such as a heated nip.

The heating of the conductive material to a temperature exceeding acharacteristic melting temperature of the conductive material results in amelting and solidification of the conductive material. This may in itself besufficient to form the electrically conductive pattern, in particular if the heatingalso involves contacting the transferred particles with pressure.

However, the method may also comprise a step of applying a pressureonto the heated conductive material, subsequent to the heating but prior tolamination. This pressure may be applied by a nip (not shown), and preferablythe surface temperature of the nip is lower than the characteristic meltingtemperature. This pressure is preferably applied relatively soon after theheating, so that the material still remains in a melted or almost melted state.Hereby, the pressure will cause the previously melted material to solidify inthe form of an essentially continuous, electrically conductive layer that coversan area on the face material web corresponding to the intended electricallyconductive pattern. 16 The nip may be a non-heated nip. However, preferably, the nip isheated to a temperature only somewhat lower than the characteristic meltingtemperature, such as 30-60 degrees C lower. This ensures for example thatthe melt will not solidify prematurely, before it would become pressed againstthe substrate. The nip will cause the previously molten material of theoriginally solid electrically conductive particles to solidify again, but this timenot in the form of separate particles but in the form of an essentiallycontinuous, electrically conductive layer, arranged in the predeterminedpattern.

However, in other embodiments, the nip temperature may be equal oralmost equal to the characteristic melting temperature of the used electricallyconductive material.

Further, as already discussed, the pressing step may in someembodiments be omitted. Still further, other nips used in the process, e.g. thelamination nip discussed in more detail below, may be arranged to provide apressure sufficient also for solidifying the melted particles, even without anyadditional pressing step prior to lamination.

The electrically conductive solid particles may be of any metal, andmay e.g. be of pure metal. However, the particles are preferably formed ofalloys, and most preferably non-eutectic alloys. ln particular, it is preferred touse particles of metallic compounds that are - or resemble - so-called lowtemperature solders. The alloys preferably comprise tin and bismuth.

A non-limiting example list of such metallic compounds includes(indicated percentages are weight percentages): o tin /silver (3.43 percent) /copper (0.83 percent)o tin / silver (2-2.5 percent) /copper (0.8 percent) / antimony (0.5-0.6 percent)o tin / silver (3.5 percent) / bismuth (3.0 percent)o tin /zink (10 percent) 17 o tin / bismuth (35-58 percent) o tin / indium (52 percent) o bismuth (53-76 percent) / tin (22-35 percent) / indium (2-12percent) o tin (35-95 percent) / bismuth (5-65 percent) / indium (0-12percent).

At room pressure, the first four listed examples melt between 180 and220 degrees centigrade, while the four Iast-mentioned may melt atsignificantly lower temperatures, even below 100 degrees centigrade.

Preferably, the particle-type conductive matter consists essentially ofmetal or metal alloy particles. The metal or metal alloy preferably has anatmospheric-pressure characteristic melting temperature of less than 300degrees C, and more preferably less than 250 degrees C, and mostpreferably less than 200 degrees C, such as in the range 50-250 deg. C, orpreferably within the range 100-200 deg. C, which makes the methodsuitable, for example, for conventional paper, the physical properties of whichmay permanently change at too high temperatures. Suitable metals include,e.g. tin, bismuth, indium, zinc, nickel, or similar, used as single metals or incombinations. For example, tin-bismuth, tin-bismuth-zinc, tin-bismuth-indiumor tin-bismuth-zinc-indium in different ratios may be used. ln tin-containingalloys, the ratio of tin in the alloy is preferably 20 - 90 wt- percent, and mostpreferably 30 - 70, wt- percent of the total weight of the components in thealloy.

One possible embodiment for transferring the conductive material tothe substrate web has been discussed in detail above. However, other waysof obtaining this conductive material transfer are also feasible. The materialtransfer may e.g. be obtained by: - Transfer roll having electrodes, which are in different potential than the particle deposited on the surface of the transfer roll.

- Electro-photographic transfer, where the particles may be depositedin a solvent. The solvent is evaporated or absorbed by thesubstrate (in particular paper or board), where after the sintering iscarried out for (almost) dry particles. 18 - Screen printing, where particles in liquid form (i.e. where particlesare arranged in solvent or suspension) are transferred to thesubstrate through a web-like screen means (cloth or metal) orthrough a stencil.

- Gravure printing, flexographic printing, offset printing, ink-jet printingor the like of particles dissolved or suspended in carrier medium.

Further, other ways of forming the conductive material in a pattern canalso be used. For example, the forming of the conductive pattern can bemade by printing with silver ink, i.e. ink comprising conductive silver particles.The solvent can then be evaporated by means of heating at an elevatedtemperature, by use of photonic curing, or the like. The forming of theconductive pattern can also be made by first providing a conductive layer onthe web, and the removing or forming this conductive layer into the desiredconductive pattern, e.g. by means of grinding, cutting, or the like.

At a second input or unwind station 101b, a second roll 102b ofasecond substrate web 200b is provided on a second reel holder. The secondsubstrate web may e.g. be a paper material, and may e.g. be the samematerial as in the first substrate web 200a. However, it is also possible to usedifferent material in the two substrates. The second substrate web can be ofany width and thickness. However, the width preferably corresponds to thewidth of the first substrate web.

The second substrate web is also provided with electrically conductingpattern, to form second antenna elements to be provided in the RFIDtransponder. To this end, there is, similar to the discussion above in relationto the first web, provided a particle handler 103b, arranged to transfer aconductive material in a pattern onto a surface of the substrate web.

The conductive material is then cured to form a solidified, more compactpattern. This can e.g. be made by application of heat with a heater 104b.Hereby, the conductive material is preferably heated to a temperatureexceeding a characteristic melting temperature of the conductive material.The forming of the second antenna elements can be made in the same wayas for the first antenna elements, or alternatively be varied and different inaccordance with the discussion above. 19 The first antenna elements and the second antenna elements arecomplementary to each other, and thereby together, when combined, formthe entire antenna of the RFID transponder. Each antenna is further providedwith an antenna terminal, to be electrically connected to a correspondingantenna contact of an IC. This will be discussed in more detail in thefollowing.

When the antenna elements have been provided on the first substrateweb, the first substrate web continues to an adhesive applicator 105,providing a layer of adhesive on a surface of the substrate web. The adhesivemay e.g. be a pressure sensitive adhesive (PSA) or a pressure sensitive hotmelt adhesive. Further, the adhesive is preferably a non-conductive adhesive,such as a non-conductive paste (NCP), or an anisotropic conductive paste(ACP). The adhesive/paste is preferably arranged for thermal compressionbonding. The adhesive is preferably applied in liquid form, and cured/solidifiedwhen heated. However, acrylic adhesive,, hot-melt adhesive or any othersuitable adhesive may also be used. The adhesive can, additionally oralternatively, be provided after placement of the IC.

Thereafter, the first substrate is brought to a transfer device 106arranged to place IC:s at suitable positions on the first substrate. The IC:s aredual-sided lC:s, each having a circuit block electrically coupled to a firstantenna contact, disposed on a first external surface, and a second antennacontact, disposed on second, opposite external surface of the IC. The IC:smay e.g. be of any of the types disclosed in US 9489611 and US2014/0144992, said documents hereby incorporated in their entirety byreference.

The IC:s are placed over the antenna elements of the first substrateweb, and more particularly so that the first antenna contacts of the IC:s comein mechanical contact with the first antenna terminals of the first antennaelements.

The transfer device may comprise a pick-and-place equipment or thelike, picking the IC:s from a storage supply, such as a stack, a container, abatch hopper, a wafer or the like, and placing the IC:s at the intended position on the first substrate web. The picking tool may e.g. operate by vacuum.However, due to the relatively large tolerances allowed, the placement of thelC:s on the first web can also be obtained in simpler ways. For example, thelC:s may simply be dropped onto the first substrate web from a short height,and at controlled times.

Due to the high tolerances, placement of the lC:s can be made whilethe web is moving. However, if there is need for higher precision, the webmay alternatively be brought to intermittent quick halts during the placement.

The two webs, the first substrate web with the first antenna elementsand the lC:s placed in contact with the first antenna elements, and theadhesive, and the second substrate web with the second antenna elementsare then brought together, and laminated in a lamination nip 109. The websare brought together so that the second antenna contact of the lC:s, arrangedon the opposite side of the lC:s, and facing away from the first substrate web,towards the second substrate web, are brought into contact with the secondantenna terminals, provided on the second antenna elements. The laminationnip 109 exerts a pressure towards the webs, thereby effecting lamination.However, the lamination nip may also optionally be a heated nip, thereby alsoeffecting lamination by additional heating.

The substrates are further heated to a temperature exceeding thecharacteristic melting point of the material forming the antenna elements, andin particular at the areas corresponding to the first and second antennaterminals. The heat can be applied by the nip 109. However, additionally oralternatively, heat can be provided upstream or downstream from thelamination nip 109. The heating of the antenna terminals makes the materialsolder into contact with the antenna contacts of the IC, thereby forming anelectrical contact between the first antenna contact and the first antennaterminal, and between the second antenna contact and the second antennaterminal, respectively.

After lamination, a die cutter 110 or the like may be provided in order toseparate the labels/tags from each other, and to provide the desired shapeand dimensions of the labels/tags. The die cutting station may e.g. be used toperforate the web, or completely cut through the web material along cutting 21 lines. The die cutting station is preferably held in registration with the insertionstations so that the Iaminated label web may be cut without cutting through anelectrically conductive pattern. The die cutting station may comprise cuttingelements, e.g. in the form of one or more rotary die or other types of toolingfor cutting or perforating used for forming labels or tags. The die cuttingstation may also comprise a monitor or sensor to identify the location of theelectrically conductive pattern, to ensure that cutting does not occur over theelectrically conductive patterns.

Further, a waste matrix removal station 110 may be provided, and theremoved matrix may be rolled onto a waste roll 111.

The finished, Iaminated web may then be re-winded onto a third roll113 at a re-winding station 112.

The labels may also be provided with an additional layer of adhesiveon an outer surface, useable to adhere the label to packages, containers andthe like. ln that case, the labels may further comprise an easily removablerelease liner to cover the adhesive.

The labels may further comprise printed information, in the form of text,digits, bar codes, etc. To this end, the system may further comprise a printingstation, e.g. for printing the first substrate web. The printing station (notshown) can e.g. be arrange prior to the particle handler 103. However, the roll102 of substrate web may also comprise pre-printed label stock. The printingcan be made by flexographic printing, off-set printing or any other printingmethod.

The re-winding station 113 may also comprise post-processing meansthat are configured to post-process the final web, for example by cooling,removing static electric charge, coating, evaporation of volatile components ofsubstances present within or on the web, or the like.

One or more tensioning devices (not shown) may also be providedalong the production line, to control the tension of the webs, as is per seknown in the art. ln the above-discussed method and apparatus, the complete RFIDtransponders are formed within a single process, including formation of theantenna elements, placement of the lC:s and connecting the lC:s to the 22 antenna elements. However, alternatively, the antenna elements may beprovided on the substrate webs in a separate procedure, and the rolls ofsubstrate webs already containing the antenna elements may be used asinput material for a process in which the lC:s are brought into place and thewebs are laminated. Such an embodiment is illustrated in Fig. 2.

Additionally, a programming and/or testing station may be provided. Atthe programming and/or testing station, the RFID transponders may beprogrammed, in case they are not preprogrammed before placement on thelabels, and the function of each RFID transponder may be tested and verified.The programming and/or testing station may comprise an interrogator systemcomprising an RFID antenna or multiple antenna arrays for checking andtesting the functionality of each RFID transponder. More specifically, thestation may comprise an RFID reader or an RFID reader/writer. ln the process of Fig. 2, rolls 102a' and 102b' of substrate websalready having antenna elements are provided at a first and second input orunwind stations 101a' and 101b', provided with reel holders. The antennaelements on these substrates may e.g. be produced in the same way asdiscussed above in relation to the first embodiment.

One of the substrate webs then passes an adhesive applicator 105,and an IC placement device 106, in the same way as discussed above. Thetwo webs are then brought together, to form contact between the antennaelements and the lC:s, and heat and pressure is applied by the lamination nip109, and the final web is assembled on an output roll 113.

Pre-forming of the antenna elements on the substrate webs, as in theFig 2 embodiment, is particularly advantageous if the same type of antennaelements is used on the two webs. ln this case, the two substrate webs canbe formed in the same process, and using the same production equipment.

Similar to the first embodiment, the lamination and the forming of theelectric contact to the IC can be made by hot nips. However, it is alsopossible to use multiple hot nips, a pre-heater unit in combination with a coldnip, etc. ln an alternative solution, as illustrated in Fig 3, the heating is providedby a hot roller 109' with defined web tension. The web tension hereby presses 23 the IC antenna contacts and the antenna terminals together, and this, incombination with the heating, makes appropriate bonding to occur. Suchbonding can be done at very high speed, since only a short time (typicallyless than 1 s) is needed.

The electrical connection between the antenna contacts and theantenna terminals are, as discussed previously, formed by the heat andoptional pressure applied, thereby soldering the antenna terminals onto theantenna contacts. However, in particular if relatively large antenna contacts,such as pads extending over a substantial part of the IC surface, are used,the need for heat and pressure is lowered, since the electric contact may alsobe formed by capacitive coupling between the antenna contact and theantenna terminal. ln particular, it may be advantageous to use such relativelylarge antenna contacts, e.g. in the form of pads, at the antenna contactarranged towards the substrate web on which the IC is first placed. Hereby,the electrical connection becomes less sensitive to disturbances caused bythe adhesive and the like.

The connection of the antenna elements and the IC:s will now bediscussed in more detail, with reference to the embodiment illustrated in Fig.4 a-c. ln Fig. 4, the first and second substrate webs 200a and 200b areillustrated. Each comprises a plurality of antenna elements 201a, 201 b. Theantenna elements form part of a dipole antenna, and each terminates in anantenna terminal 204a, 204b. The antenna elements are producible in theways discussed in the foregoing, and the antenna elements may take manydifferent shapes and dimensions, as will be discussed in further detail in thefollowing.

An IC is placed over each antenna terminal 204a on the first substrateweb 200a, and the second substrate web 200b is then laminated over the firstsubstrate web, as discussed above. Hereby, the antenna terminals 204a and204b are connected to the antenna contacts 203a, 203b arranged on eachside of the IC, thereby together forming an antenna for the RFID transponder.This is illustrated in Fig 4b and Fig 4c. 24 ln the previously discussed embodiments, the first antenna elementsare provided on a first substrate, and the second antenna elements areprovided on a second substrate, being separate from the first substrate.However, it is also possible to provide the first antenna elements on a firstsubstrate area on a substrate, and to provide the second antenna elementson a second substrate area on the same substrate. After placement of thelC:s on the antenna terminals on the antenna elements on the first substratearea, the substrate is folded, so that the second substrate area is placed overthe lC:s in the intended position, to be laminated and electrically connected.

Thus, the production apparatus for such an embodiment may berealized in a similar way as in the previously discussed embodiments, but withonly one input substrate web.

Such a substrate web, to be used in a folding substrate, is illustrated inFig. 5. ln this embodiment, the same type of antenna elements as discussedin relation to Fig. 4 are used. However, in this embodiment, a single substrateweb is provided, comprising a first substrate area 200a' and a secondsubstrate area 200b'. The first and second substrate areas are separated bya folding line 205. The first antenna elements 201a are provided on the firstsubstrate area 200a', and the second antenna elements 201 b are provided onthe second substrate area 200b'.

After placement of the lC:s on the antenna elements on the firstsurface area 200a', the substrate is folded, in a folding station, so that thesecond surface area 200b' comes into contact with the lC:s. The antennaelements are then heated to laminate the surface areas together, and to formthe electrical contact between the antenna terminals and the antennacontacts in the same way as in previously discussed embodiments.

The antenna elements may be designed and dimensioned in manydifferent ways. ln the previously discussed embodiment, the antennaelements are extending symmetrically outwards from a centrally arranged IC.ln another embodiment, as illustrated in Fig. 6, the antenna elements 201a'and 201 b' are arranged in a side-by-side arrangement, with the antennaterminals provided on the same side of the antenna, and both the antennaterminals extending in the same direction in relation to IC 202. ln the illustrative example, the antenna elements are arranged on a single substrate,foldable along a folding line 205, but the same principle may be used in a twosubstrate embodiment. ln the embodiment of Figs. 5 and 6, the antenna elements extend in adirection along the width direction of the substrate. However, the antennaelement may also extend along the longitudinal direction of the substrate, asillustrated in Fig. 7, where the antenna elements 201a" and 201b" extend inthe length direction of the substrates, and are foldable over each other. Again,the same principle may be used in a two substrate embodiment. ln the above-discussed embodiments, the substrate is provided in aroll, to be used in a roll-to-roll process or a roll-to-sheet process. However, theinput substrate(s) may also be provided in the form of sheets. The sheetsmay e.g. be die-cut blanks for packages.

The previously discussed antennas, having antenna elements ofessentially the same size, and being symmetrical to each other, are inparticular suited for use at rather high frequencies, such as the UHF (UltraHigh Frequency) band, e.g. in the range 800-1000 MHz.

However, the first and second antenna elements may also bedifferently sized and shaped. Thus, the first antenna element may form X% ofthe antenna, whereas the second antenna element forms 100-X% of theantenna, where X is any number between 1 and 99. Such antennas are forexample well suited for lower frequencies, such as antennas for use in the HF(High Frequency) band, e.g. at 13.6 MHz.

One such asymmetric embodiment is illustrated in Fig. 8. Here, one ofthe antenna elements 201a"', to be arranged on either the first or the secondsubstrate or substrate areas, is shaped as a helix. The helix may havecircular coils, but other shapes, such as hexagonal, octagonal, rectangular,triangular, and similar, may also be contemplated. ln the illustrative example,a rectangular helix is provided. The helix extends in widening coils from aninner first antenna terminal 204a"'. The second antenna element 201 b"' ishere in the form of a bridge, connecting the outer end of the helix to a secondantenna terminal 204b"'. 26 ln this embodiment, a foldable substrate is used, and the bridge isconnected to the helix, and extends into the other substrate area, crossing afolding line 205.

The IC is placed on either the first or the second antenna terminal, andthe substrate is then folded so that the IC also comes into contact with theother antenna terminal. ln this embodiment, the heating and optional pressing may occurlocally, only to create an electrical contact between the antenna contact of theIC and the antenna terminals, and to avoid short circuiting between the helixand the strap. However, in order to further avoid such short circuiting, theadhesive may in this embodiment be of a kind providing a dielectric layerbetween the HF antenna helix and the bridge. The bridge pattern may alsohave adhesive coating of the area that needs to be electrically insulated fromthe helix pattern. ln this embodiment, the lamination is preferably made withno or relatively low heating, such as by using a cold nip.

However, the bridge may also, alternatively, be provided on a separatesubstrate, as illustrated schematically in Fig. 8. Fig. 8a illustrates the twosubstrate webs, a first substrate web 200a being provided with a helixantenna pattern 201a"", and a second substrate web 200b being providedwith a bridge antenna pattern 201 Again, an adhesive providing dielectricproperties may be used to avoid short circuiting.

After placement of an IC between the antenna terminals, a localheating may be applied, connecting the ends of the bridge to the IC antennacontact at one end, and to the outer end of the helix at the other end. Thismay e.g. be accomplished by a fork-like heating element 109', as illustrated inFig 8b. ln this embodiment, depending on the adhesive used, there may beno need for a nip or any application of pressure.

Specific embodiments of the invention have now been described.However, several alternatives are possible, as would be apparent forsomeone skilled in the art. For example, various ways of providing thetransfer and curing of the conductive material for obtaining the electricallyconductive pattern is feasible. Further, the electrically conductive pattern mayfunction as different types of antennas, and not only dipole antennas. Further, 27 lamination may be obtained by use of a pressure sensitive adhesive, andapplication of a pressure to the webs to be Iaminated, but other ways oflaminating the webs are also feasible. Further, placement and attachment ofthe integrated circuit to the electrically conductive pattern can be provided asintegrated steps in the process of forming the labels, but may alternatively beprovided in a separate process. Such and other obvious modifications mustbe considered to be within the scope of the present invention, as it is definedby the appended claims. lt should be noted that the above-mentionedembodiments i||ustrate rather than limit the invention, and that those skilled inthe art will be able to design many alternative embodiments without departingfrom the scope of the appended claims. ln the claims, any reference signsplaced between parentheses shall not be construed as limiting to the claim.The word "comprising" does not exclude the presence of other elements orsteps than those listed in the claim. The word "a" or "an" preceding anelement does not exclude the presence of a plurality of such elements.Further, a single unit may perform the functions of several means recited inthe claims.

Claims

1. A method for producing radio-frequency identification (RFID)transponders arranged on a carrying substrate, comprising: providing a first substrate area (200a; 200a') and a second substratearea (200b; 200b'), the first and second substrate areas each having at leastone antenna element formed by an electrically conductive pattern arrangedthereon, and preferably several antenna elements arranged sequentiallythereon along a longitudinal extension of the first and second substrate areas,wherein a first antenna element (201a; 201a'; 201a”; 201a'”, 201B””) arrangedon the first substrate area (200a; 200a') has a first antenna terminal (204a;204a”'), and a second antenna element (201 b; 201 b'; 201b”; 201b”'; 201b””)arranged on the second substrate area (200b; 200b') has a second antennaterminal (204b; 204b”'); providing a dual-sided integrated circuit (IC) (202) including a firstcircuit block electrically coupled to a first antenna contact (203a), disposed ona first external surface of the IC, and a second antenna contact (203b),disposed on a second external surface of the IC opposite the first externalsurface of the IC; arranging the IC on the first substrate area (200a; 200a'), whereby thefirst antenna contact (203a) comes in mechanical contact with the firstantenna terminal (204a; 204a”'); bringing the first substrate area (200a; 200a') and the second substratearea (200b; 200b') together, thereby bringing the second antenna contact(203b) in mechanical contact with the second antenna terminal (204b;204b”y heating the first and second substrate areas in the vicinity of the IC(202) to a temperature at least equal to a characteristic melting point of saidfirst and second antenna terminals, thereby forming electric contact betweenthe first antenna contact (203a) and the first antenna terminal (204a; 204a”'),and between the second antenna contact (203b) and the second antennaterminal (204b; 204b”').

2. The method of claim 1, wherein said heating is provided using acontactless heating technique.

3. The method of claim 1 or 2, further comprising pressing the firstand second substrate areas against each other over the IC (202), during orafter said heating.

4. The method of any one of the preceding claims, wherein anadhesive is arranged on at least one of the first and second substrate areas,the adhesive being arranged to adhere the first and second substrate areastogether after the first and second substrates have been brought together.

5. The method of any one of the preceding claims, wherein at leastone of the first and second substrate areas are made of at least one of:paper, board, polymer film, textile and non-woven material.

6. The method of any one of the preceding claims, wherein the firstand second antenna terminals are made of an alloy comprising tin andbismuth.

7. The method of any one of the preceding claims, wherein thecharacteristic melting point is less than 300 °C, and preferably less than 200°C, for example in the range from 100 °C to 200 °C.

8. The method of any one of the preceding claims, wherein the firstsubstrate area (200a) is provided on a first substrate, and the secondsubstrate area (200b) is provided on a separate second substrate.

9. The method of any one of the claims 1-7, wherein the first andsecond substrate areas (200a'; 200b') are provided on the same substrate,wherein the substrate is folded to bring the first substrate area and thesecond substrate area together.

10.and second substrate areas are provided on at least one web, the web(s)being provided in the form of roll(s) (102a; 102b; 102a'; 102b'), and whereinthe method is a roll-to-roll process.

11.RFID transponders arranged on a carrying substrate forms RFID labels orRFID tags. The method of any one of the preceding claims, wherein the first The method of any one of the preceding claims, wherein the

12. The method of any one of the preceding claims, wherein the firstantenna element (201a; 201a'; 201a”; 201a'”, 201B””) and the secondantenna element (201b; 201b'; 201b”; 201b”'; 201b””) when electricallyconnected to the IC together form an antenna for the RFID transponder,wherein the first antenna element forms X% of the antenna and the secondantenna element forms 100-X% of the antenna, where X > 0. 13.one of the first antenna contact (203a) and the second antenna contact

13. The method of any one of the preceding claims, wherein at least (203b) includes a conductive pad spanning substantially an entirety of the firstexternal surface or the second external surface of the IC, respectively. 14.one of the first and second antenna elements are formed by conductive

14. The method of any one of the preceding claims, wherein at least material in the form of electrically conductive solid particles.15.forming of the conductive material in a pattern in at least one of the first and

15. The method of any one of the preceding claims, wherein the second antenna elements comprises: transferring a conductive material in a pattern corresponding to saidelectrically conductive pattern to a surface of a substrate; and heating the conductive material to a temperature exceeding acharacteristic melting temperature of the conductive material. 16.material to the surface of the substrate comprises direct printing of electrically

16. The method of claim 15, wherein the transferring of conductive conductive particles as a part of a compound that contains, in addition ofelectrically conductive solid particles, a fluid or gelatinous substance. 17.applying a pressure onto the heated conductive material prior to arranging theIC (202) on the first substrate area (200a; 200a') and bringing the firstsubstrate area and the second substrate area (200b; 200b') together. 18.(109; 109'), wherein the surface temperature of the nip is lower than said

17. The method of claim 15 or 16, further comprising a step of

18. The method of claim 17, wherein pressure is applied by a nip characteristic melting temperature.19.transponder on a carrying substrate, comprising:

19. An apparatus for producing a radio-frequency identification an input station (101a; 101a') to receive one or more substrate, thesubstrate(s) having a first substrate area (200a; 200a') and a secondsubstrate area (200b; 200b'), the first and second substrate areas eachhaving at least one antenna element formed by an electrically conductivepattern arranged thereon, and preferably several antenna elements arrangedsequentially thereon along a longitudinal extension of the first and secondsubstrate areas, wherein a first antenna element (201a; 201a'; 201a”; 201a”',201 B””) arranged on the first substrate area (200a; 200a') has a first antennaterminal (204a; 204a”'), and a second antenna element (201 b; 201 b'; 201b”;201b”'; 201b””) arranged on the second substrate area (200b; 200b') has asecond antenna terminal (204b; 204b'”); a placement device (106) arranged to place a dual-sided integratedcircuit (IC) (202) on the first substrate area (200a; 200a'), the IC (202)including a first circuit block electrically coupled to a first antenna contact(203a), disposed on a first external surface of the IC, and a second antennacontact (203b), disposed on a second external surface of the IC opposite thefirst external surface of the IC, and wherein the IC (202) is placed on the firstsubstrate area (200a; 200a') in such a way that the first antenna contact(203a) comes in mechanical contact with the first antenna terminal (204a;204a”y a transfer device configured to bring the first substrate area (200a;200a') and the second substrate area (200b; 200b') together, thereby bringingthe second antenna contact (203b) in mechanical contact with the secondantenna terminal (204b; 204b'); a heating device configured to heat the first and second substrateareas in the vicinity of the IC (202) to a temperature at least equal to acharacteristic melting point of said first and second antenna terminals,thereby forming electric contact between the first antenna contact (203a) andthe first antenna terminal (204a; 204a”'), and between the second antennacontact (203b) and the second antenna terminal (204b; 204b”').

20. The apparatus of claim 19, further comprising a pressing devicearranged to press the first and second substrate areas against each otherover the IC.

21. The apparatus of claim 20, wherein the pressure is applied by anip (109), wherein the surface temperature of the nip is lower than saidcharacteristic melting point.

22. The apparatus of any one of the claims 19 to 21, furthercomprising an adhesive applicator (105), arranged to provide an adhesive onat least one of the first and second substrate areas, the adhesive beingarranged to adhere the first and second substrate areas together after the firstand second substrate areas have been brought in mechanical contact.