EP3362592A1

EP3362592A1 - Inclusion of chip elements in a core yarn

Info

Publication number: EP3362592A1
Application number: EP16794691.2A
Authority: EP
Inventors: Jean Brun
Original assignee: Commissariat a lEnergie Atomique CEA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2015-10-12
Filing date: 2016-10-10
Publication date: 2018-08-22
Also published as: FR3042203B1; FR3042203A1; US20180355524A1; US10640892B2; WO2017064402A1

Abstract

The invention relates to a method for producing a core yarn which comprises the following steps: moving a core (13) axially through a reaming area (21); winding a sheathing fibre (14) around the core at the reaming area; and presenting, in the reaming area (21), a microelectronic chip (10) attached to the core (13). A polymer material is provided between the microelectronic chip (10) and the core (13) during the reaming step. The polymer material then flows during the reaming step in order to form a protective shell.

Description

INCORPORATION OF CHIP ELEMENTS IN

GUIPE WIRE

Technical field of the invention

The invention relates to microelectronic chip elements and more particularly to microelectronic chips, the largest dimension of which may be less than one millimeter. The invention relates more particularly to a method of packaging such chip elements to facilitate storage and handling.

STATE OF THE ART FIG. 1 schematically represents a miniaturized radiofrequency transmission-reception device, serving for example for a contactless identification (RFID type device). The device comprises a chip element 10, of parallelepipedal general shape, incorporating a chip that integrates all the RFID functions. The device comprises a dipole antenna formed of two sections of conducting wire 11a and 11b. These sections, secured to two opposite faces of the element 10, are connected to terminals of the chip and depart in opposite directions.

The larger side of the chip element 10 may be smaller than 1 mm, these devices are not manufactured and manipulated by the methods used for larger devices.

The patent application WO2009004243 describes an exemplary method for producing RFID devices of the type of FIG. Once realized, these devices must be incorporated into the objects to be identified. This poses handling problems, because the antennas must remain substantially straight, or at least not be twisted to short circuit.

US 2013-0092742 discloses a method of attaching chip elements to a core to form a gimped wire. The chip elements are caught by a cladding fiber which fixes the chip elements on the core by compressing them. Alternatively, GB2472025 proposes to secure a semiconductor chip with a wire. The fastening can be carried out by means of a resin. According to the embodiments, the resin may be applied over the entire length of the wire, on the chip or on a substrate supporting the chip. It is also possible to use an additional element comprising the resin. This additional element is disposed between the wire and the chip.

GB2472026 discloses an assembly of a semiconductor chip provided with conductive elements within a wire. Conductor wires can be introduced to provide power. The chip is inserted inside a carousel whose periphery contains a multitude of thread. The wires can be coated with resin.

GB2426255 also discloses an assembly of a semiconductor chip provided with conductive elements within a wire. The chip is disposed in a volume of resin which is closed at its periphery by contiguous wires.

JP2013-189718 proposes to put an electronic article on a wire and to surround the electronic article and the wire by an additional wire to secure them.

It appears that in these various embodiments and for some applications, the functionality of the covered yarn is reduced in time. Failures are observed which reduces the interest of this innovation for certain applications.

SUMMARY OF THE INVENTION Thus, a solution is needed to increase the durability of the guiped yarn functions while retaining the ability to manipulate group-based or individualized chip elements, in particular when they are very difficult. small size, especially when they are equipped with stretches of wire.

To tend to satisfy this need, there is provided a method of producing a covered yarn, comprising the following steps: • Provide a core and at least one microelectronic chip associated with wire stretches;

• Put the microelectronic chip and the wire sections in contact with the core; · Winding at least one cladding fiber around the microelectronic chip, wire sections and the core at at least one wrapping zone to form the wrapped wire;

The method is remarkable in that a polymeric material is present between the core and the microelectronic chip before winding the cladding fiber around the microelectronic chip and the core and in that the cladding fiber is wrapped around it of the microelectronic chip and the core so as to force the creep of the polymeric material through the turns of the cladding fiber to form a protective coating around the microelectronic chip.

It also provides a wrapped wire comprising a core around which is wound at least one cladding fiber, at least one microelectronic chip taken between the core and the cladding fiber. The wrapped yarn is remarkable in that it comprises a polymeric material encapsulating the microelectronic chip, the cladding fiber comprising a peripheral zone devoid of polymeric material.

BRIEF DESCRIPTION OF THE DRAWINGS Other advantages and features will emerge more clearly from the following description of particular embodiments given by way of nonlimiting examples and illustrated with the aid of the appended drawings, in which: FIG. 1, previously described, schematically represents a chip element provided with a dipole antenna; FIGS. 2a, 2b and 2c schematically represent different steps of a wrapping process in a wrapping installation for incorporating chip elements on a wire provided with a sticky zone; FIGS. 3a, 3b and 3c schematically represent different steps of a wrapping process in a wrapping installation used to incorporating chip elements on a wire, the chip element being at least partially covered with a sticky zone; FIG. 4 schematically represents a covering installation for incorporating chip elements on a wire; - Figure 5 schematically shows an alternative covering installation for incorporating chip elements on a wire; FIG. 6 diagrammatically represents yet another variant of a covering installation for incorporating chip elements on a wire; - Figure 7 schematically shows a section of wire covered with the previous Pinstallations facilities.

Description of a preferred embodiment of the invention

In order to facilitate the handling of individual chip elements of very small size (which may be less than 1 mm), it is proposed to incorporate them spaced apart in a gimped wire. The chip elements will be taken between the core of the wire and a cladding fiber wound helically around the core, that is to say in the form of turns. It is also possible to use several different or identical cladding fibers wound successively helically around the core. Coiling fiber turns are made around the assembly formed by the core and the microelectronic chip. The core wire has a longitudinal axis which is identical or substantially identical to the longitudinal axis of the assembly which is not the case of the cladding fiber.

This embodiment is more advantageous than the formation of a sheath around the chip by means of a plurality of cladding fibers without using a core because the position of the chip is better controlled and the behavior over time is improved. . Using a core wire ensures the guidance of the microelectronic chip during the wrapping of the cladding fiber. By guiding the cladding fiber around the chip placed on the core, it is possible to reduce the risk of random winding and the risk of folding antennas when they are present on the chip. So that the chip elements also called microelectronic chips do not tend to escape between the consecutive turns of the cladding fiber, they are advantageously provided with sections of wire also taken between the core and the cladding fiber. These wire segments may advantageously be the dipole chip element antennas integrating radiofrequency or RFID transmission-reception functions.

The wrapped thread, wound on a spool, is easily manipulated. In addition to the fact that the yarn can be used to make fabrics, it can be cut and incorporated into other objects, manually or automatically, limiting the risk of losing the chip elements or twist the dipole antennas.

The core may be formed by a monofilament or by multi-filaments, advantageously the multi-filaments are braided.

As illustrated in FIGS. 2c, 3c and 7, in order to protect the microelectronic chips against the aggressions of the external environment, it is particularly advantageous to protect them by means of a polymer material 12 which will form a protective coating, that is, a carapace.

The polymer material 12 will also ensure the attachment between the microelectronic chip 10, the core 13 and the turns of the cladding fiber 14 which improves the resistance over time of the guiped wire by reducing friction between the turns. This friction can induce damage to the cladding fibers 14, for example a cut. Once the cladding fibers 14 are cut, chip slip may be possible out of the wrapped wire. According to the embodiments, the cladding fiber can completely cover the core 13 or partially so as to define covered areas and open areas. The coated zone advantageously comprises a microelectronic chip.

Particularly advantageously, the protective coating of polymer material 12 is hermetic so as to prevent moisture from reaching the microelectronic chip 10. A simple way to protect the chip 10 is to make the wrapped wire then to come and coat the assembly in the polymer material 12. The coating is then performed after the microelectronic chip 10 is brought into contact with the core 13 and after that the turns of cladding fibers 14 are formed. It has been observed that this type of encapsulation is not completely satisfactory because the polymer material 12 has difficulties to infiltrate through the turns and reach the microelectronic chip 10. Holes exist where the polymer material 12 is absent. which facilitates, for example, the infiltration of moisture. It has also been observed that the level of protection is even lower than the polymer material 12 is disposed, far from the microelectronic chip 10, outside the covered wire and therefore in an area that is particularly subject to the wear.

It has further been observed that the probability of obtaining a coating reaching the microelectronic chip 10 is even lower as the viscosity of the polymer material is high, for example in the range 5000mP / s - 50000mP / s. Such a viscosity value can be obtained during the deposition of the polymer material 12 which can take place at ambient temperature, for example between 20 ° C. and 30 ° C. The probability of obtaining a coating reaching the microelectronic chip 10 is also a function of the wettability which is a parameter dependent on the surface state of the gimped wire, the core and the microelectronic chip.

As indicated above, the wrapping is made by surrounding the cladding fiber 14 around the assembly formed by the core 13 and the chip 10. This embodiment makes it possible to better control the pressure applied by the cladding fiber and therefore to better control the expulsion of the polymer material. Such mastering of the expulsion of the resin is difficult to obtain in the embodiment of GB2472026 which does not provide for the rotation of the fibers, nor even the use of a core wire.

It has also been observed that in the use of a polymer material 12 comprising fillers, for example metal or alumina fillers, the latter have difficulties in reaching the microelectronic chip 10. The charges are very predominantly present on the surface of the wrapped thread, that is to say around the sheathing fibers 14. The loads have difficulties to pass to through turns to reach the inside of the guiped wire, that is to say the core 13 and the microelectronic chip 10.

In this case, the charges can not perform their function near the microelectronic chip 10 because they are absent or in small quantities. In addition, the pile of loads may form an extra thickness which can be inconvenient for future applications of yarn guiped. This cluster will also be used more quickly because it is in overthickness around the turns. In order to facilitate the penetration of the polymer material 12 as close as possible to the microelectronic chip 10, different paths are possible. A first way is to apply pressure around the wrapped wire covered with polymer material 12 to force its infiltration through the turns. This implementation is particularly complex to achieve and it does not allow to place any charges of the polymer material 12 as close to the microelectronic chip 10.

An advantageous embodiment is to place the polymer material 12 between the core 13 and the microelectronic chip 10 before the wrapping step, that is to say before forming the turns of cladding fiber 14. According to the embodiments of FIG. The cladding fiber is formed by a monofilament or a multi-filament, advantageously the multi-filaments are braided. This embodiment makes it possible to keep a large quantity of the charges in the immediate vicinity of the chip. In such an embodiment, it is possible to obtain a concentration of charges which is decreasing from the chip 10 to the periphery of the assembly.

It may be advantageous to use electrically insulating charges and / or charges formed from oxides.

It is advantageous to choose fillers that are configured to improve the thermomechanical properties of the polymer material 12 and in particular to bring the thermomechanical properties of the polymer material 12 together with its charges to the equivalent thermomechanical properties of the microelectronic chip 10. In this way, by introducing specific charges into the polymer material 12, the assembly formed by the polymer material 12 and the charges has thermomechanical properties closer to those of the microelectronic chip 10. It is particularly advantageous to choose charges which are configured to approximate the coefficient of thermal expansion of the assembly formed by the polymer material 12 and the charges of the thermal expansion coefficient of the microelectronic chip 10. The coefficient of thermal expansion is for example the coefficient of linear thermal expansion. It is also advantageous to provide charges which are configured to bring the coefficient of thermal conduction closer to the assembly formed by the polymer material 12 and the charges of the thermal conduction coefficient of the microelectronic chip 10.

Under these conditions, the protective coating around the chip is able to place charges in the immediate vicinity of the chip to effectively protect against moisture and the loads also reduce mechanical stress when the temperature of the chip and the protective coating evolve.

According to the embodiments, the charges have an optionally linear coefficient of thermal expansion and / or a coefficient of thermal conduction which are strictly lower than that of the polymer material and which are advantageously less than or equal to that of the microelectronic chip 10 and even more advantageously which are less than or equal to that of the microelectronic chip 10. It is also possible to provide that the charges are formed by different materials, for example with a first part of the charges which has a coefficient of thermal conduction between that of the polymer material 12 and that of the microelectronic chip 10 and / or a second part which has a coefficient of thermal conduction equal to that of the microelectronic chip 10 and / or a third part which has a coefficient of thermal conduction lower than that of the microelectronic chip 10. It may be the same for the coefficient of thermal expansion. In the case where the chip 10 is formed on a silicon substrate, it is advantageous to use charges which have a coefficient of thermal expansion and / or thermal conduction equal to or substantially equal to those of silicon. In a particular embodiment illustrated in FIGS. 2a, 2b and 2c, the polymer material 12 covers the core 10 and the microelectronic chip 14 is placed on the polymer material 12. Depending on the case, the core 13 may be completely or partially covered by the polymeric material 12. In the case of partial coverage, it is advantageous to use the zone of polymer material 12 as a receiving zone to place the microelectronic chip 10. The cladding fiber 14 is advantageously provided to from a roll 16.

FIG. 2a illustrates the provision of a core partially covered by the polymer material 12 and the provision of a microelectronic chip 10. FIG. 2b illustrates the placement of the chip 10 on the core 13. The chip 10 is fixed by means of of the polymeric material 12 which ensures the bonding between the chip 10 and the core 13. FIG. 2c illustrates the formation of the turns of cladding fibers 14 which will compress the polymer material. The polymeric material will flow to form a protective wrapper around the chip 10.

In an alternative embodiment illustrated in FIGS. 3a, 3b and 3c, the polymer material 12 covers the microelectronic chip 10 and the microelectronic chip 10 covered is placed on the core 13. According to the embodiments, the chip 10 can be completely or partially covered by the polymer material 12.

FIG. 3a illustrates the supply of a core 13 and the supply of a microelectronic chip 10 partially covered by the polymeric material 12. FIG. 3b illustrates the placement of the chip 10 on the core 13. The chip 10 is fixed at means of the polymeric material which ensures the bonding between the chip 10 and the core 13. FIG. 3c illustrates the formation of the turns of cladding fibers 14 which will compress the polymer material. The polymeric material will flow to form a protective wrapper around the chip 10.

It is still possible to provide a combination of these two embodiments, that is to say that the microelectronic chip 10 and the core 13 are covered by a polymer material 12. It is possible to use the same polymeric material or two different polymeric materials for covering the core 13 and the microelectronic chip 10.

The microelectronic chip 10 is placed on the core 13 by means of a polymer material 12 which ensures the retention of these two elements during the formation of the turns. The polymeric material 12 is advantageously an adhesive. The chip 10 may be placed on the core 13 when the core 13 is moving or when the core 13 is stopped.

When the cladding fiber 14 is wrapped around the microelectronic chip 10 and the core 13 at the wrapping zone to form the wrapped wire, the polymer material 12 is present between the core 13 and the microelectronic chip 10 and it will flow through the turns of the cladding fiber 14 so as to form the protective layer. If the cladding fiber 14 is multi-filaments, the polymeric material 12 advantageously flows between the filaments of the fiber 14.

In this configuration, the polymer material 12 is closer to the microelectronic chip and the core. During creep, the polymeric material will coat the core and the chip before or during the infiltration of the polymeric material through the turns of cladding fiber 14. The polymer material advantageously goes between the turns of the cladding fiber 14.

In this way, the protective layer around the microelectronic chip 10 and around the core 13 is of better quality because it is more continuous. The probability of having a hole favoring the arrival of moisture or impurities is reduced. This effect is particularly pronounced when the polymer material 12 has a high viscosity, for example in the range indicated above. It also appears that when the polymer material 12 comprises charges, for example the charges indicated above, the latter are mainly concentrated around the microelectronic chip and the core 13 because the spiral-shaped cladding fiber 14 slows down their progression towards the outside of the gimped yarn. In this configuration, the extra thicknesses are reduced or non-existent. In these cases, the polymeric material 12 fixes the microelectronic chip 10 with the core 13 and the turns which allows to increase the service life of the covered yarn. In a particular embodiment, the voltage applied by the cladding fiber 14 during the formation of the turns and the polymer material 12 are configured to flow a portion of the polymer material 12 through the turns during the step of forming the turns. turns. In an alternative embodiment, the turn applies a stress on the assembly formed by the core 13, the microelectronic chip 10 and the polymer material 12. Annealing may be applied to the assembly so as to fluidize the polymer material 12 which will flow more easily through the turns. The increase in temperature will accentuate the phenomenon of infiltration of the polymer material 12 in a manner analogous to an improvement in the wettability. Tests have been carried out with the EPOTECHNY E505 glue. It has been observed, during the rise in temperature up to 160 ° C, that the glue becomes more fluid and that it wets the core 13 and the microelectronic chip 10 more. The sheath fiber 14 is at a first temperature in the coil 16 and wound on the core 13 at a second temperature which may be the same or different from the first temperature. The annealing step advantageously results in an increase of the temperature of at least 5 ° C, preferably at least 10 ° C.

In an advantageous embodiment, an annealing step is performed after the formation of the covered yarn. The annealing is configured so as to cause the polymerization of the polymer material which will permanently fix the microelectronic chip 10 with the core 13 and the turns. Annealing may also be used to accelerate the polymerization. The annealing step advantageously results in an increase of the temperature of at least 5 ° C, preferably at least 10 ° C. This embodiment is particularly advantageous for crosslinking or accelerating the crosslinking of the polymer material 12 and preventing its deformation over time. The polymer material 12 is for example a partially cross-linked thermosetting material or an adhesive. The polymer material may for example be an epoxy adhesive capable of being shaped twice, for example with a hot impregnation followed by an annealing step. This type of epoxy glue is used for example to form high density printed circuits. Alternatively, it is also possible to use a UV adhesive which polymerizes on the surface during an exposure and then to the heart during a posterior annealing. In another embodiment, it is still possible to anneal the polymer material at a temperature close to the glass transition temperature to reduce its viscosity and make it less tacky to the touch. The term "temperature close to the glass transition" advantageously means a temperature of between + 10 ° C. and -10 ° C. with respect to the glass transition temperature and even more advantageously a temperature of between + 5 ° C. and -5 ° C. compared to the glass transition temperature. A second anneal at a higher temperature is carried out so as to finalize the crosslinking.

The polymerization of the adhesive is advantageously carried out between 130 ° C. and 220 ° C. The adhesive may be an epoxy adhesive, for example a TC420 epoxy adhesive marketed by Polytech PT or an epoxy adhesive E514 sold by EPOTECNY.

Moreover, after the formation of the covered yarn, it is particularly advantageous to wind the wrapped yarn to form a coil. In this configuration, it is particularly advantageous to perform a first annealing after the formation of the covered yarn and before reeling. This first annealing is intended to achieve a partial polymerization of the polymer material for example glue. This first annealing is advantageously carried out in a temperature range of between 130 ° C. and 200 ° C. After this first annealing, the covered yarn may be reeled and a second annealing is preferably performed on the spool of yarn. This second annealing is configured to complete the polymerization of the adhesive and preferably to obtain a total polymerization of the adhesive. The second annealing is advantageously carried out in a temperature range of between 150 ° C. and 220 ° C. The temperature of the second annealing is greater than the temperature of the first annealing. It is particularly advantageous to carry out the first annealing during the winding phase, which allows a better management of the viscosity. This embodiment is particularly advantageous for epoxy glues whose viscosity decreases during a rise in temperature, for example from 40 ° C. to 80 ° C., for a few seconds before increasing again under the effect of crosslinking. There is then increased impregnation of the glue in the inner part of the yarn then a blocking of diffusion towards the outside because the polymer material reacted.

In an alternative embodiment, the polymer material 12 is a thermoplastic material. It is particularly advantageous to heat the thermoplastic material before placing the microelectronic chip on the core by means of of a first annealing. Heating the thermoplastic material makes it softer and increase its tackiness. Thus, the microelectronic chip 10 is bonded to the core 13 by means of the polymer material 12 during the covering step, which is particularly advantageous for ensuring proper placement of the microelectronic chip 10 on the core 13. The first annealing is advantageously carried out in a temperature range of between 150 ° C. and 200 ° C. The annealing can be carried out by heating the coil 16 or advantageously by heating the polymer material 12 between the exit of the coil and the securing with the core. A second annealing is then performed after the covering step, so as to flow the polymer material around the microelectronic chip 10 and around the core 13 to reach the cladding fiber 14. The second annealing is advantageously achieved in a temperature range between 160 ° C and 240 ° C. The temperature of the second annealing may be higher or lower than the temperature of the first annealing because the objective is to put the polymer material in the pasty state. The temperature difference between the two anneals is advantageously at least 5 ° C, preferably at least 10 ° C.

The polymer material 12 may be chosen from polyurethanes or silicones. In an even more specific embodiment, the core 13 and the polymer material 12 are made of thermoplastic materials or comprise a thermoplastic material. According to the embodiments, the same thermoplastic material or two different thermoplastic materials can be used to form the core 13 and the polymer material 12. If the core 13 is a multi-filament, it is advantageous to provide at least one filament in thermoplastic material and advantageously in the same thermoplastic material as that used for the polymer material 12. It is also advantageous to use different materials, for example different thermoplastic materials that will flow differently, which preserves the mechanical properties of the soul 13 or polymer during the realization.

It is still possible to provide a core of a first material covered by a thermoplastic material different from the material of the core. In a variant, the soul 13 can be formed completely by a thermoplastic material. In this case, it is advantageous to make the core 13 in a thermoplastic material having a glass transition temperature greater than that of the thermoplastic material forming the polymeric material in order to maintain the mechanical integrity of the assembly during annealing. For example, a temperature difference of 10 ° C is advantageously chosen.

The second annealing may be configured to flow the polymer material 12 and a portion of the core 13 around the microelectronic chip 10 until it reaches the cladding fiber 14. In yet another embodiment, the core 13 is formed by thermosetting material filaments and the polymeric material 12 is formed in the core 13 by thermoplastic filaments. The thermoplastic material is present in the core 13 and also at its periphery. During the two previous anneals, the thermoplastic material reacts to stick the microelectronic chip and then to encapsulate it.

The core 13 is for example made of multi-filaments Co-Polyester (Co PES) or Co-Polyamide (Co PA), such a yarn is for example sold by the company DISTRICO under the name GRILON® thermocollant thread. It is possible to use yarns formed by a polyamide / polyester core associated with a Co-Polyester (Co PES) or Co-Polyamide sheath. These yarns are sold under the name GRILON® two-component yarns. It is still possible to use a core 13 for example made of multi-filaments Co-Polyester (Co PES) or Co-Polyamide (Co PA) associated with a non-fusible core wire and sold under the name GRILON® combi wire fusible . Placing the polymer material in direct contact with the microelectronic chip 10 before the formation of the turns reduces the amount of polymer material 12 used while ensuring optimal protection of the chip 10. This makes it possible to reduce or even avoid clusters of material around the guiped thread. Reducing the amount of polymer material also makes it possible to reduce the differences in mechanical behavior between the zones with chip and polymer material and the zones without chip and without polymer material.

It is then possible to choose the amount of polymer material 12 so that the polymer material 12 does not overflow beyond the last layer of cladding fiber turns 14 during creep. It is even more advantageous to choose the amount of polymer material 12 so that the polymer material 12 leaves, on the different turns surrounding the microelectronic chip 10, an outer zone devoid of polymeric material 12. For example, for a unit of given length, the volume of polymer material 12 is less than the volume of wrapping fiber 14 wound. This outer zone may have the shape of a continuous ring around the chip 10.

To attach the microelectronic chip 10 to the core 13, it seems advisable to use several bonded bonding areas. That is to say at least two zones provided with polymer material 12 separated by a zone devoid of polymer material 12.

This embodiment is particularly advantageous when the microelectronic chip 10 comprises an RFID device provided with an antenna. The antenna is fixed to the core by means of a specific zone of polymer material 12.

Figure 4 schematically shows a conventional covering installation that can be used to incorporate chip elements 10 in a wire covered with simple modifications.

A core 13 unwinds from a supply spool 15, axially passes through two successive rollers, 16 and 17, and ends wound on a take-up spool 18. Each of the rollers 16 and 17 stores a cladding fiber and is associated with a mechanism turning around the soul being scrolled, and wrapping around it the sheathing fiber. The two winding mechanisms rotate in opposite directions, from which it follows that the outgoing guiped yarn comprises two layers of cladding fiber, formed of helices of opposite directions. The ratio of the running speeds of the core and the rotation of the winding mechanisms defines the pitch of the propellers.

As shown, it is conventional to work vertically from bottom to top, i.e., the feed reel 15 is at the bottom, and the reel 18 at the top. The winding mechanisms are, in Figure 4, provided for winding the cladding fiber around the core 13 at the exit of the rollers (in the running direction of the core). However, a horizontal configuration is not prohibited. In order to incorporate chip elements in the wire being formed, an insertion device 19 is provided, preferably at the level of the first roller 16. This insertion device 19, for example in the form of a tube of diameter adapted to the chip elements 10, guides them to an attachment zone 20 where the chip is fixed on the core 13.

The chip fixed on the core 13 then arrives at a wrapping area 21 where the cladding fiber of the roll 16 is wrapped around the core 13. This tube passes through the roll 16 from bottom to top and opens near the area 21. Alternatively, the guide tube may be replaced by a chute, that is to say a half-tube in the longitudinal direction, or by a roller guide system.

The individual elements are, for example, projected with compressed air through the tube 19 to bond to the core by means of the polymeric material. The core then moves to the area 21 where the chips 10 and the core 13 are compressed by the cladding fiber during winding. Advantageously, the microelectronic chip 10 is brought parallel to the core 13.

Figure 5 shows another possible configuration of the roller 16 with its winding mechanism. The winding of the cladding fiber around the core 13 takes place at the entrance of the roll (in the running direction of the core 13). The wrapping area 21 is therefore located at the entrance of the roll 16. This configuration makes it possible to use a shorter insertion device 19 since it no longer has to traverse the roll 16. This facilitates the feeding of the device. insertion into chip elements 10.

In order to make it possible to feed the insertion device 19 by gravity, which would further simplify the process, it is possible to envisage reversing the installation, that is to say scrolling the core 13 from the top to the bottom. .

FIG. 6 shows yet another possible configuration where a coil of cladding fiber moves around the core wire 13 by unwinding itself so that the cladding fiber wraps around the core 13. The movement of the coil 16 around the soul 13 is represented by the arrow.

In a first embodiment illustrated in FIG. 4, the core 13 leaves the coil 15 devoid of polymeric material 12. A zone for depositing the material polymer is present between the coil 15 and the zone 20 where the chip 10 is fixed to the core 13. The deposition machine 22 comes to deposit polymer material on the core 13.

The deposition of the polymer material 12 can be carried out according to any known technique. The polymeric material 12 may be continuously deposited to cover the entire length of the core 13 or discontinuously to form zones of polymer material 12 separated by zones devoid of polymeric material 12.

The discontinuous deposit can be made by depositing one or more drops of polymer material 12 on the core 13. It is also possible to deposit the polymer material 12 on the core 13 by projection, for example by means of a jet of polymeric material 12. A discontinuous deposition of polymeric material 12 can be further achieved by coating.

The deposition of material 12 or the formation of drops can be obtained by means of equipment marketed by the company Nordson Asymtek. The formation of drops can also be obtained by dipping a tip in the polymer material 12 in the liquid state and then transfer on the core 13 by contact between the core 13 and the tip or possibly the liquid polymer material 12. The polymer material 12 may be deposited on the moving core 13 or the core 13 is stopped in order to place the polymer material 12.

What has been presented for the deposition of the polymer material 12 on the core 13 can also be realized for the deposition of the polymer material 12 on the chip 10.

As indicated above, if anneals are used to promote the polymerization of the polymer material 12, it is advantageous to place an oven 23, 24 after the roll 16, for example between the roll 16 and the roll 17 or after the roll 17. In the example illustrated in Figure 4, a first oven 23 is disposed between the rollers 16 and 17 and a second oven 24 is arranged to anneal the coil 18. Figure 7 shows a section of guiped wire obtained at the output of the first roller 16, illustrating a chip element 10, with its wire sections 11a and 11b, taken between the core 13 and the spirally wound cladding fiber, coming from the roller 16. It is sought to have the wire sections 1 1a and 1 1b substantially parallel to the core 13, as shown.

For this type of microelectronic chip 10, it is advantageous to use several different zones of polymeric material in order to fix the chip to the core in the desired configuration. For example, three separate areas of polymeric material are used. A first zone of polymeric material is used to fix and encapsulate the chip 10. Two additional zones of polymeric material are preferably used at the ends of the wire sections 11a and 11b in order to fix the orientation of the chip antennas. 10. The amount of polymer material can be reduced which limits the final volume occupied by the polymeric material.

Claims

claims

1. A method of producing a covered yarn, comprising the following steps:

• Provide a core (13) and at least one microelectronic chip (10) associated with wire sections (1 1 a, 1 1 b), · Connect the microelectronic chip (10) and the wire sections (1 1 a, 1 1 b) with the soul (13);

• Wrap at least one cladding fiber (14) around the microelectronic chip (10), wire strands (11a, 11b) and the core at at least one wrapping zone to form the guiped thread; characterized in that a polymeric material (12) is present between the core (13) and the microelectronic chip (10) before winding the cladding fiber (14) around the microelectronic chip (10) and the and that the cladding fiber (14) is wrapped around the microelectronic chip (10) and the core so as to force the flow of the polymeric material (12) through the turns of the cladding fiber (14). ) to form a protective coating around the microelectronic chip (10).

2. Method according to claim 1, wherein the core (13) is provided covered by the polymeric material (12).

3. The method of claim 2, wherein the core (13) is partially covered by the polymeric material (12), the covered areas defining the receiving areas for the microelectronic chip (10).

4. Method according to one of the preceding claims, wherein the microelectronic chip (10) is provided covered by the polymeric material (12).

5. Method according to one of the preceding claims, wherein the polymeric material (12) comprises charges preferably metal material or alumina.

6. Method according to one of the preceding claims, wherein the polymeric material (12) is a thermoplastic material (12).

7. Method according to one of the preceding claims, wherein an annealing step is performed on the guiped wire to polymerize the polymer material (12) and fasten together the core (13), the microelectronic chip (10) and the cladding fiber (14).

8. The method of claim 7, wherein an additional annealing step is performed before contacting the microelectronic chip (10) with the core (13) so as to soften the polymer material (12) and stick microelectronic chip (10).

9. The method of claim 8, wherein the core (13) and the polymeric material (12) respectively comprise a first and a second thermoplastic materials, the first thermoplastic material of the core (13) partially flowing through the turns the cladding fiber (14).

The method of claim 8, wherein the polymeric material (12) is formed by a plurality of braided filaments with the core (13).

The method according to one of the preceding claims, wherein a plurality of cladding fibers (14) are wound superimposed around the microelectronic chip (10) and wherein the amount of polymer material (12) and the amount of cladding fibers (14) are chosen so that an outer portion of the cladding fibers (14) is free of polymeric material (12) after creep.

12. Method according to one of the preceding claims, wherein the microelectronic chip (10) comprises at least two areas in contact with the polymeric material (12) separated by a zone free of contact with the polymeric material (12).

13. Gimped yarn comprising a core (13) around which is wrapped at least one cladding fiber, at least one microelectronic chip (10) taken between the core (13) and the cladding fiber (14), characterized in that it comprises a polymeric material (12) encapsulating the microelectronic chip (10), the cladding fiber (14) having a peripheral zone devoid of polymeric material (12).