Patent Document

RELATED APPLICATION 
   This application is a division of U.S. patent application Ser. No. 10/422,616, filed Apr. 24, 2003, now U.S. Pat. No. 7,191,507, which claims the benefit of U.S. Provisional Patent Application No. 60/375,249, filed Apr. 24, 2002, both of which are incorporated by reference herein in their entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to a method of manufacturing a wireless communication device for use in communication of information concerning an item containing the wireless communication device. 
   BACKGROUND OF THE INVENTION 
   It is often desired to track and identify items, such as packages, containers, and the like, and to communicate information concerning such items wirelessly. One method of tracking and providing information concerning packages is to attach a wireless communication device, such as a radio frequency identification (RFID) transponder or other identification device, to packages or items. The information communicated concerning the packages or items may include an expiration date, “born on” date or date of manufacture, lot number, tracking information, or other manufacturing information, and the like. A wireless communication device may be attached to an individual package, to a container containing multiple packages, or other item as the situation merits. 
   Recent advances in the miniaturization of wireless communication electronics have enabled the creation of small chips, containing integrated circuits, that are well suited for use in these wireless communication devices. However, these chips still need antennas to communicate to a remotely positioned interrogator. Numerous potential antennas exist that may be coupled to the chip for this purpose. 
   It is expected that the demand for such devices will rapidly increase as industries realize the versatility and utility of the wireless communication devices. To meet this demand, automated manufacturing processes are needed. Further, the process contemplated should provide a wireless communication device well suited for integration with the item to be tracked and one that may have the ability to communicate at multiple frequencies if desired. 
   SUMMARY OF THE INVENTION 
   In a first aspect, the present invention provides a number of embodiments designed to pick up chips from a carrier tape and position the chips on an adhesive production line for later incorporation into a wireless communication device. 
   A second aspect that may be used in conjunction with the first aspect comprises a combination of positioning a conductive material on a roll, cutting the conductive material to the desired shape, and peeling the conductive material from an underlying carrier material. In one embodiment of this aspect, a single roller performs the entire cut. In a second embodiment of this aspect, three separate rollers perform different cuts, allowing the size of the tabs created to be varied as needed or desired. 
   Another aspect comprises using two selectively spaced rollers to adjust the size of the tab created. In an exemplary embodiment, a testing device may assess the capacitance of the elements of the dipole with a ground layer or without a ground layer to give an estimate of the thickness and/or dielectric constant of the substrate to which the chip is being applied. Each roller may be moved independently, increasing or decreasing the size of the tab while assessing the effective capacitance until a desired value is achieved for maximum antenna performance. Upon reaching the desired values, the tabs are cut to create the antenna. 
   As yet another aspect, the present invention may insert a wireless communication chip into a substrate such that the chip does not protrude from the surface of the substrate. An exemplary embodiment includes punching a hole in the substrate, positioning tabs to form a dipole antenna overlapping the newly formed hole, and positioning the chip in the hole. The chip may be attached to the tabs by a low melting point solder, a conductive adhesive, welding, or a mechanical bond. 
   The aspects are mutually cooperative and allow a roll-to-roll manufacturing process to be automated for the creation of the wireless communication devices. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a top plan view of a wireless communication device assembled according to the present invention; 
       FIG. 2  illustrates a side elevational view of a carrier tape loaded with wireless communication chips; 
       FIG. 3  illustrates a side schematic view of a first technique to position chips on an adhesive production line; 
       FIG. 4  illustrates a side schematic view of a second technique to position chips on an adhesive production line; 
       FIG. 5  illustrates a more detailed view of the interface between the roller and the carrier tape of  FIG. 4 ; 
       FIG. 6  illustrates a side view of a first cutting technique for creating antenna elements for wireless communication devices; 
       FIG. 7  illustrates a top view of the first cutting technique of  FIG. 6 ; 
       FIG. 8  illustrates a side view of a second cutting technique for creating antenna elements for wireless communication devices; 
       FIG. 9  illustrates a top view of the laminate during different stages of the cutting of  FIG. 8 ; 
       FIG. 10  illustrates a side view of a third cutting technique for creating antenna elements for wireless communication devices; 
       FIG. 11  illustrates a top view of the third cutting technique of  FIG. 10 ; 
       FIG. 12  illustrates a top view of the third cutting technique of  FIG. 10  with the rollers spread; 
       FIGS. 13A and 13B  illustrate top views of the tape before and after cutting in the process of  FIGS. 10-12 ; 
       FIG. 14  illustrates a first cross-sectional view of a positioning technique for a chip to be used in a wireless communication device; 
       FIG. 15  illustrates a top plan view of an antenna element positioned on a substrate; 
       FIG. 16  illustrates a side view of the antenna element of  FIG. 15  with a chip positioned above it prior to positioning; 
       FIG. 17  illustrates a side view of the antenna element of  FIG. 16  with the chip positioned; 
       FIG. 18  illustrates an exemplary roller technique to attach the chips to the substrate of the wireless communication device; 
       FIG. 19  illustrates a more detailed view of the chip being attached to the substrate; and 
       FIG. 20  illustrates an exemplary block diagram of an entire production process using the techniques of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is a method of manufacturing wireless communication devices such as those used in co-pending, commonly assigned U.S. Pat. Nos. 6,501,435 and 6,975,834, entitled “Wireless Communication Device and Method” and “Multi-Band Wireless Communication Device and Method” respectively, both of which were filed on Oct. 3, 2000 and are incorporated herein by reference in their entireties. In particular, the present invention allows variations in the size of the tabs used for antenna elements in the wireless communication devices. 
   Some wireless communications devices have both transmit and receive capability and can be used in the present invention. A typical example of such a device is described in U.S. Pat. No. 5,585,953, entitled “IR/RF radio transceiver and method,” incorporated herein by reference in its entirety. Other wireless communication devices have receive capability and use the energy received to communicate back, such as described in U.S. Pat. No. 6,078,259 entitled “Radio frequency identification tag,” incorporated herein by reference in its entirety. Such passive devices may likewise be used with the present invention. The wireless communication device in the present invention can be any type of device that allows reception of wireless electronic communications and is able to communicate in response thereto. Both types of wireless communication devices are sometimes referred to herein and in the art as transponders. The terms are used equivalently herein. 
     FIG. 1  illustrates a wireless communication device  10 , such as that described in the previously incorporated applications. In particular, wireless communication device  10  comprises a substrate  20 , a wireless communication chip  30 , and one or more tabs  40 , to serve as an antenna  60  for wireless communication device  10 . Tabs  40 A,  40 B may be constructed out of any type of material so long as the material is conductive. Such material may be a ferrous material, including metal, steel, iron, or the material may be aluminum or other type of conducting material. 
   Tabs  40  may also be constructed from a tape impregnated with metal loaded ink, as described in U.S. Pat. No. 5,566,441, entitled “Attaching an electronic circuit to a substrate,” incorporated herein by reference in its entirety. In one embodiment of the present invention, as illustrated in  FIG. 1 , tabs  40 A,  40 B are made from a foil tape  42 ,  52  respectively as is well understood in the art. 
   An optional ground plane (not shown) may be oppositely positioned on substrate  20  if needed or desired. Substrate  20  may be almost any material, but is most likely a plastic or similar material. 
   Wireless communication chip  30  may comprise a device from INTERMEC as used in their Intellitag® labels and those devices from SCS as used in their DL100 label although other devices are certainly possible, especially in light of the present invention&#39;s suitability to both active and passive wireless communication devices  10 . Wireless communication chip  30  may comprise a controller, memory, a battery, a sensor, and other conventional components such as those described in the previously incorporated applications. 
   Tabs  40 A,  40 B together comprise dipole antenna  60 . In this particular embodiment, tabs  40 A,  40 B are asymmetrical with respect to one another to form an asymmetrical dipole antenna. An asymmetrical dipole antenna  60  is an antenna having a first tab  40 A, or first pole, different in shape, including, but not necessarily limited to length, width, volume, and/or density, from the second tab  40 B, or second pole. 
   Tabs  40 A,  40 B may also be coupled to a slot to form a slot antenna (not shown). Alternatively, a single tab  40  may be used as a monopole antenna given the appropriate ground plane (not shown). While the present invention is primarily directed to dipole antenna tab structures, it should be appreciated by those in the art that some of the techniques may be equally applicable to a single tab  40  arrangement, or an arrangement having more than two tabs  40 A,  40 B. 
   The present invention focuses on techniques to manufacture these wireless communication devices  10 . There are several different aspects to the manufacturing process. The first is properly positioning the wireless communication chip  30  for later processing, and is discussed in the chip positioning section below. The second is the creation of the tabs  40  that form the antenna  60 , addressed in a separate section below. The last is the merging of the chip  30  with the antenna  60  to form the wireless communication device  10 , discussed in the mounting techniques section below. 
   Chip Positioning Techniques 
     FIG. 2  illustrates an exemplary carrier tape  100  comprising an adhesive sealing layer  102  and a container layer  104 . Container layer  104  comprises a plurality of containers or pockets  106  having wireless communication chips  30  disposed therein. Carrier tape  100  may be made from any number of materials and is available from a number of manufacturers such as Tek Pak. Details can be found at www.tekpak.com. Adhesive sealing layer  102  initially seals the chips  30  within the containers  106 , protecting them from environmental vagaries. Subsequently, when desired, adhesive sealing layer  102  peels off of container layer  104 , leaving the contents of the containers  106  exposed for further processing. 
   There are two specifically contemplated techniques to remove the chips  30  from the carrier tape  100  for later mounting on the wireless communication device  10 . Other techniques are also contemplated to enable the roll-to-roll continuous automation process of the present invention. 
   A first technique is illustrated in  FIG. 3 . Chip positioning system  110  comprises a waste roller  112 , a first roller  114 , and a second roller  116 . Carrier tape  100  is fed to rollers  114 ,  116  simultaneously with an adhesive line  111 . Waste roller  112  wraps adhesive sealing layer  102  therearound, exposing chips  30  within the containers  106  ( FIG. 1 ). Rollers  114 ,  116  may be oval shaped and rotate at a frequency so as to space chips  30  appropriately on adhesive line  118 . The proximity of the roller  114  to roller  116  pushes the chip  30  out of the container  106  and to the sticky surface of the adhesive line  118 . This removes the chip  30  from the container  106  and allows the adhesive line  118  with the chips  30  to be passed downstream for further processing. 
   A second technique is illustrated in  FIGS. 4 and 5 . As illustrated in  FIG. 4 , chip positioning system  110 A comprises a waste roller  112 , a toothed roller  120  having teeth  122  and may have an optional second roller (not shown) comparable to second roller  116 . Carrier tape  100  is fed to the roller  120  with waste roller  112  removing the adhesive sealing layer  102  as previously described. Now with reference to  FIG. 5 , wherein a more detailed view of the interface between the teeth  122 , the containers  106 , the chips  30 , and the adhesive line  118  is illustrated, it can be seen that a tooth  122  pushes through the floor  105  of the container  106 , pushing chip  30  upwardly to contact the adhesive line  118 . Again, this removes the chip  30  from the container  106  and allows the adhesive line  118  with the chips  30  to be passed downstream for further processing. 
   Manufacture of Tabs For Antenna 
   Concurrent to the positioning of the chips  30  on the adhesive line  118 , tabs  40  may be created for the wireless communication device  10 . This section focuses on techniques by which the tabs  40  may be created that are again well suited for use in the roll-to-roll automated manufacturing process of the present invention. 
   A first technique for the creation of tabs  40 A,  40 B is illustrated in  FIGS. 6 and 7 .  FIG. 6  illustrates a tab production system  100 , comprising a pair of rollers  132 ,  134  oppositely positioned on either side of a production line  140 . Top roller  132  may comprise a die cutting roller while bottom roller  134  may be a driving roller to push material though rollers  132 ,  134 . It should be appreciated that rollers  132 ,  134  may be reversed if production line  140  is inverted. Production line  140  may also comprise a backing layer  142 , an adhesive (not shown explicitly) and a conductive foil  144 , such as a copper foil, an aluminum foil, or the like. As production line  140  passes through rollers  132 ,  134 , die cutting roller  132  cuts conductive foil  144  into one or more tabs  40 . In this particular embodiment, die cutting roller  132  cuts conductive foil  144  into two tabs  40 A,  40 B. Waste foil  146  is peeled from backing layer  142  while tabs  40 A,  40 B and backing layer  142  continue for further processing. Tabs  40  are then used to form antenna elements for antenna  60  on the wireless communication device  10  as explained below. 
   To accommodate substrates  20  that may have varying dielectric constants and/or thicknesses (such as may occur when switching materials having different dielectric constants forming substrate  20 ) variations may need to be made to the dimensions of tabs  40 A,  40 B to produce the optimum read range at the desired operating frequency. To ensure optimal antenna  60  performance using tabs  40 A,  40 B with chip  30 , energy transfer should be maximized between chip  30  and tabs  40 A,  40 B to maximize emitted radiation from tabs  40 A,  40 B. To ensure maximum energy transfer, the impedance of tabs  40 A,  40 B must be substantially matched to the impedance of chip  30 . 
   Further information on impedance matching between wireless communication devices and antennas is described in the previously incorporated U.S. Pat. Nos. 6,501,435 and 6,975,834, and co-pending U.S. Pat. No. 6,642,897 entitled “Tuning Techniques for a Slot Antenna,” filed on Apr. 18, 2002, by the same assignee as that of the present application and incorporated herein by reference in its entirety. 
   A first technique to address this situation is illustrated in  FIGS. 8 and 9 . In this technique, a plurality of rollers  200 ,  202 ,  204  is used. In particular, tab production system  130 A receives production line  140 . A first roller  200  makes an initial cut  206  in conductive foil  144 . This initial cut  206  comprises the inner portions of tabs  40 A,  40 B. A second roller  202  makes a second cut  208  in conductive foil  144  that completes the creation of one of tabs  40 A,  40 B (in this case tab  40 A). Second cut  208  overlaps to a certain extent initial cut  206  of first roller  200 . A third roller  204  makes a third cut  210  in conductive foil  144  that completes the creation of the other one of tabs  40 A,  40 B (in this case tab  40 B). Third cut  210  overlaps to a certain extent the initial cut  206  of first roller  200 . Note that the precise order of the cutting by rollers  200 ,  202 ,  204  may be varied. For example, a first cut could begin on the left edge, beginning tab  40 A, a second cut ends tab  40 A and begins tab  40 B, and the third cut ends tab  40 B. Other variations are also contemplated. 
   The technique of  FIGS. 8 and 9  allows the sizes of the tabs  40 A,  40 B to be varied by varying the phases of rollers  202 ,  204  with respect to first roller  200 . Thus, if a longer tab  40 A is desired, second roller  202  is phased such that there is little overlap between the cuts  206 ,  208 . If a shorter tab  40 A is desired, second roller  202  is phased such that there is substantial overlap in the cuts  206 ,  208 . The same principle applies to the size of tab  40 B, but the phase of third roller  204  is modified to achieve the desired amount of overlap between the cuts  206 ,  210 . Allowing for differently sized tabs  40 A,  40 B allows optimal antenna  60  performance as previously explained. It should be appreciated that rollers  200 ,  202 ,  204  rotate at the same rate to avoid undesired phase changes between rollers  200 ,  202 ,  204 . This technique is especially well suited for situations in which substrate  20  varies between wireless communication devices  10 . In one embodiment, it is expected that at a 200 ft/min rate of movement of production line  120 , and an antenna  60  dimension of approximately 68 mm×16 mm outside dimensions, thus giving about 60 antennas 60 per foot, approximately 12,000 antennas may be made per minute. 
   An alternate technique to provide variations in the size of tabs  40 A,  40 B is illustrated in  FIGS. 10-13B . In this technique, production system  130 B comprises a first roller  300  and a second roller  302 , each of which is independently movable relative to one another. This technique is better suited for situations in which substrate  20  on which wireless communication device  10  is to be placed varies, as this technique allows testing on the fly to get the desired impedance for antenna  60  in conjunction with substrate  20 . Rollers  300 ,  302  receive a production line  140 A (illustrated in  FIG. 13A ) comprising a backing material  130  with tabs  40 A,  40 B, and chip  30  disposed thereon. In contrast to the other techniques previously discussed, this technique positions, but does not specifically require, chip  30  mounted with the elements that form tabs  40 . 
   Production line  140 A passes under first roller  300  and second roller  302  to deposit the tabs  40  and the chip  30  onto the substrate  20 . Rollers  300  and  302  may initially be close together as illustrated by dimension ‘X’ in  FIGS. 10 and 11 . During the deposit of tabs  40 A,  40 B on substrate  20 , a low signal level and low frequency radiator  138 , operating at, for example, 125 khz, assesses the capacitance of tabs  40 A,  40 B in conjunction with substrate  20  and with or without ground plane  306  ( FIG. 10 ). This provides an estimate of the thickness and dielectric constant of substrate  20 . Tabs  40 A,  40 B may be sized appropriately to provide the desired capacitance by moving the rollers  300 ,  302  to insure optimal antenna  60  performance as previously discussed. 
   As illustrated by the difference between  FIGS. 11 and 12 , rollers  300 ,  302  may be spread if larger tabs  40 A,  40 B are required. After the testing equipment determines that the tabs  40  are appropriately sized to give the desired performance to antenna  60 , a cut is made and tabs  40 A,  40 B are mounted on substrate  20 . This cut may be made with a die, a knife, a laser, or other appropriate cutting tools (none shown). It may be desirable to test capacitance by changing one and then the other tab  40 A,  40 B as needed or desired. As can be seen in  FIG. 13B , the cut removes tabs  40 A,  40 B and a portion of the backing material  130  to create hole  121 , leaving tab residuals  40 ′,  50 ′. 
   As previously noted, some of the above techniques may be occurring concurrently with the positioning of the chips  30  on the adhesive line  118 . The following section deals with mounting the chips  30  on the wireless communication device  10  after the antenna  60  has been positioned thereon. 
   Mounting Techniques 
   One technique is illustrated in  FIG. 14 . In particular, a hole  22  is punched into substrate  20 . Hole  22  is any type of cavity in substrate  20  or any type of geometry such that wireless communication chip  30  may be wholly or partially placed inside such cavity. Hole  22  may have tapered top edges  24  that taper from a wide opening  26  to a narrow mouth  28 , The size of narrow mouth  28  may be the same or smaller in size than the width of wireless communication chip  30 , so that wireless communication chip  30  rests in hole  22  at the point where narrow mouth  28  begins. 
   Foil tape  42 ,  52  overlaps edges  24  so that tape  42 ,  52  extends partially into hole  22 . Chip  30  is then inserted in the direction of the arrow into the hole  22 . Hole  22  may be designed to allow chip  30  to sit flush with upper surface  21  of substrate  20  without substantially protruding therefrom, as is illustrated in  FIG. 14 . This reduces the profile of substrate  20  and protects chip  30  from some inadvertent harm. Hole  22  may also be designed to allow chip  30  to sit fully below upper surface  21  or to protrude slightly from hole  22  depending on the design and size of hole  22 , edges  24 , and mouth  28 . 
   A number of techniques exist to attach chip  30  to tabs  40 A,  40 B. A first technique comprises using a low melting point solder. Tape ends  44 ,  54  of foil tape  42 ,  52  may be pre-loaded with a solder paste. Chip  30  is then simply dropped onto the paste (not shown), and the solder (not shown) is melted to form connectivity between tabs  40 A,  40 B and chip  30 . Appropriate methods to form the solder joint comprise the use of infrared radiation to heat the joint locally, or pushing chip  30  into the paste with pins  32  of chip  30  preheated. Preheating of pins  32  allows the solder to remain in a liquefied state longer after initial melting so that solder may more easily flow to more surface area of tabs  40 A,  40 B and around pin  32  to form a stronger bond. Such preheating may be accomplished by any technique, including use of a preheating tool that emits heat such as a hot gas jet or the like. 
   An alternative technique for attaching chip  30  to tabs  40 A,  40 B comprises the use of a conductive adhesive (not shown). The adhesive forms a bond between tabs  40 A,  40 B and chip  30 , and the conductivity of the adhesive ensures electrical continuity between tabs  40 A,  40 B and chip  30 . Either a suitable conductive adhesive can be applied by printing to ends  44 ,  54  of tape  42 ,  52  prior to assembly, or chip  30  may be pushed onto a pressure sensitive conductive adhesive on top surfaces  46 ,  56  of tape  42 ,  52  It may be advantageous, but not required to use an adhesive that can be cured rapidly. For example, an adhesive cured by a flash of ultraviolet (UV) light would be appropriate. Examples of conductive adhesives include isotropic conductive adhesives, conductive silicones, and anisotropic conductive adhesives. The interested reader is directed to  Electrically Conductive Adhesives Characteristics and Applications , a Loctite Corporation publication available at www.loctite.com that is hereby incorporated by reference in its entirety. Further information may also be found at the following website: www.chemical,felpro.com/electronics/elec_tech_index.html#eleccond. 
   Yet another alternative is illustrated in  FIGS. 15-17 . In this embodiment, the tape  42  has one end sliced into a plurality of fingers  43 . Note that the fingers  48  are made from the same material as the tape  42 , but include cuts  49  between the fingers  48 . The fingers are then placed proximate the hole  22 . A top view of the tape  42 , the fingers  48 , and an exemplary positioning relative to the hole  22  is illustrated in  FIG. 15 . With that arrangement in place, it is now possible to mount the chip  30 . 
   Chip  30 , and particularly pins  32  thereof, are heated above the yield point of substrate  20  and positioned over substrate  20  ( FIG. 16 ). Pins  32  are then forced into substrate  20  with fingers  48  wrapping around pins  32 , as illustrated in  FIG. 17 . The heat of pins  32  melts substrate  20 , which then cools around tape  42  and pins  32  forming an effective mechanical bond. Also note that this technique could also be done on the other tab  40 B (not shown) in a similar fashion. Note that both tabs  40 A,  40 B should be in place prior to this insertion. 
   Still another alternative would be to weld or tack pins  32  to tape  42 ,  52  using a suitable tool. The tool presses chip  30  into surface  21  of substrate  20 . A high current may be passed through pins  32 , using a low voltage pulse therethrough to form the weld. A lower voltage pulse is desirable so as to not apply a damaging voltage to chip  30 . A modified chip  30  with a single thin foil (not shown) rather than multiple pins  32  may also be used for this technique. This technique may be better suited for chips  30  having an aluminum thin foil rather than a copper thin foil, since aluminum has a melting point temperature lower than copper thereby allowing use of a current that is lower in Amperes. 
   With all of these embodiments, a sealing layer (not shown) may also be placed onto substrate  20  and over chip  30  to hold chip  30  firmly in its desired location. This sealing layer may be an epoxy, but may instead be a robust plastic such as polyimide, Mylar, or polypropylene. These plastics may be attached by adhesives or by thermal welding as needed or desired. 
   It should be noted that extra layers may be added to wireless communication device  10  after or in place of the sealing layer. For example, a paper layer for printing or plastic layers may be added to the structure. Such sealing layer or layers may be applied onto substrate  20  using any type of label printing machine. 
   For almost any of the above styled processes, the chip  30  may be positioned on the substrate  20  with rollers as illustrated in  FIGS. 18 and 19 . Chip merging system  160  is illustrated schematically in  FIG. 18  and comprises a first and second heat and pressure roller  162 ,  164 . These rollers  162 ,  164  may perform the thermal welding alluded to above. Adhesive line  118  with chips  30  disposed thereon passes between rollers  162 ,  164  and mates with substrate  20 , and particularly hole  22  of substrate  20  as better seen in  FIG. 19 . Tabs  40  have been pre-positioned on substrate  20  prior to the introduction of the chip  30  thereto. Chip  30  may be secured to the tabs  40  and the substrate  20  by any of the means previously discussed as needed or desired. 
   The above-mentioned techniques are useful with a number of other manufacturing techniques. Of particular interest is the creation of tabs  40 A,  40 B. This may be done before, concurrently with, or after the creation of hole  22  in substrate  20  as needed or desired. 
   The present invention is well suited for “roll to roll” processes, making the automation of the present invention easy. As illustrated in  FIG. 20 , the chip  30  positioning process may be occurring concurrently with the tab  40  creation process. The tabs are then positioned on the substrate  20  through an appropriate means as is well understood. Finally the two production lines merge and the chip  30  may be positioned on the substrate  20 . Furthermore, the automation may test and mark defective parts as needed or desired. 
   The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments are therefore to be construed in all aspects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Technology Category: 4