Electrical component assembly on flexible materials

The present invention provides a method and a structure of electrical component assembly on flexible materials. In an exemplary embodiment, the method and the structure include patterning metal on a tape, creating one or more holes in the tape, attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, electrically connecting the one or more electronic devices to the patterned metal, cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions comprises at least one of the one or more electronic devices, attached to the patterned metal, and bonding the one or more component portions to a ribbon.

BACKGROUND

The present disclosure relates to the packaging of several electrical components, and more specifically, to electrical component assembly on flexible materials.

SUMMARY

The present invention provides a method and a structure of electrical component assembly on flexible materials. In an exemplary embodiment, the method includes patterning metal on a tape, creating one or more holes in the tape, attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, electrically connecting the one or more electronic devices to the patterned metal, cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions comprises at least one of the one or more electronic devices, attached to the patterned metal, and bonding the one or more component portions to a ribbon.

In an embodiment, the structure includes a tape, a patterned metal on the tape, one or more holes in the tape, one or more electronic devices attached to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, and one or more electrical connections formed between the patterned metal and the one or more electronic devices.

In an embodiment, the method includes patterning metal on a tape, creating one or more holes in the tape, attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, electrically connecting the one or more electronic devices to the patterned metal, and cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions comprises at least one of the one or more electronic devices attached to the patterned metal, where the patterned metal forms one or more antennas, where the cutting determines a length of the one or more antennas.

DETAILED DESCRIPTION

The present invention provides a method and a structure of electrical component assembly on flexible materials. In an exemplary embodiment, the method includes patterning metal on a tape, creating one or more holes in the tape, attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, electrically connecting the one or more electronic devices to the patterned metal, cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions comprises at least one of the one or more electronic devices, attached to the patterned metal, and bonding the one or more component portions to a ribbon.

In an embodiment, the structure includes a tape, a patterned metal on the tape, one or more holes in the tape, one or more electronic devices attached to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, and one or more electrical connections formed between the patterned metal and the one or more electronic devices.

In an embodiment, the method includes patterning metal on a tape, creating one or more holes in the tape, attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, electrically connecting the one or more electronic devices to the patterned metal, and cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions comprises at least one of the one or more electronic devices attached to the patterned metal, where the patterned metal forms one or more antennas, where the cutting determines a length of the one or more antennas.

Internet of things (IoT) devices have the promise of introducing sensing, computation, storage, and input-output (I/O) communication that can be embedded into many materials to help provide a smarter material. For example, sensors in an IoT device have the ability to sense environmental aspects around the material of interest, such as temperature, humidity, shock, vibrations, pH, and other aspects such as tracking, etc. Embedded computation logic and memory on the same IoT device can interpret the sensors' data and execute “computation at the edge”. Lastly IoT device I/O communication circuitry, such as RF circuitry enabled by onboard antennas, can provide a communication channel for sending/receiving data between IoT devices and/or a more centrally monitored system such as a cloud computing system or a smart phone. To enable these functionalities, the physical form of IoT devices need to be compatible with the many materials that they are embedded in.

Of particular emerging interest are IoT devices that can be embedded into paper based materials, such as banknotes, legal documents, tickets and smart labels, clothing, fabrics or other flexible media. It may be beneficial for IoT devices to be thin, flexible, and small to enable the devices to withstand the rigors of daily use with minimal change (for example, the smallest change realistically possible) to the paper or to the IoT device.

Scaling RF antenna size down to a size suitable for embedding in thin and flexible IoT devices while maintaining transmission reliability can be challenging. It is often beneficial to reduce the size of antenna to decrease costs, improve robustness and reliability, and reduce noticeability in thin materials (i.e. paper). However, to maintain good signal-to-noise integrity at low transmission power levels, antennas maximize signal efficiency at ¼ the wavelength of transmission. Some attempts have been made to reduce the antennas sizes of the IoT devices, but these attempts came at the expense of increased power consumption to overcome reduced antennas efficiency. Many remote scaled IoT devices will rely on harvesting—limited power from incoming RF or other means, and cannot afford any inefficiencies. Other attempts have been made to decrease the wavelength of transmission by increasing the RF transmission frequency. However, higher RF transmission frequencies cause RF communications to become more confined to direct line of sight, or in general, shorter transmission distances. Scaling antenna size for each particular application can be beneficial for certain applications.

Another challenge to integrating IoT devices into paper is the package integration of an antenna that have scaling limitations with a scalable IoT device that continues to scale with technology iterations. The assembly process for these devices may require different assembly tools of different tolerances. For example, a single electronic device or chip could be used for several different applications, but with traditional processing, modifying the antenna size could require significant modifications to the assembly process.

In an embodiment of the present invention, an electronic device is attached to a film (e.g., a flexible photographic or video film) and a metal antenna is printed onto the film. The flexibility of the film can increase the robustness of the device/antenna. In an embodiment, the film is processed with a reel to reel process. In an embodiment, the reel to reel process includes transferring tape wound on a first reel to a second reel by winding the tape on the second reel and unwinding it from the first reel. In an embodiment, the method includes transferring the tape from a first reel to a second reel. In an embodiment, a reel is processed with a reel to reel process at a first station and transferred to a second station for a second reel to reel processing. In an embodiment, a reel is run through several processing stations during one reel to reel transfer. In an embodiment, an antenna could be printed in such a way that a continuous cutting of the film by an adjustable cutting implement could produce antenna of various lengths.

In an embodiment, a location of the cutting determines a length of the patterned metal on both the one or more component portions and the one or more excess portions of the tape. Further, it may be advantageous in some applications to have more than one antenna printed with each IoT device, to enable, for example, transmission at one or more frequencies (wavelengths) and/or reception at one or more frequencies (wavelengths). One such application would enable cross-talk free communication with different sources and/or different IoT devices communicating in different frequencies. The present embodiment allows multiple antennas per IoT device to also be printed in such a way that a cutting or stamping of the film produces several antennas of different lengths.

In an embodiment, a film is used to process electronic devices. For example, a 35 mm film, similar to those used for motion pictures, could be used to make an RF transmitter and antenna. Other commonly used films may include 45 mm and 70 mm, or any other width. In an embodiment, a film is a tape. In an embodiment, a tape is a film. In an embodiment, a reel is a canister in which a tape or a film is wound. In an embodiment, reel to reel processing is removing a film or tape from one reel, processing the tape, and winding the tape on another reel.

Referring toFIGS. 1A and 1B, in an embodiment, a film110with feeder holes170is used. In an embodiment, film110is one section of a longer strip of film. In an embodiment, film110is wound on a reel. In an embodiment, the film is transferred from one reel to another during processing. In an embodiment, the tape has holes along at least one edge of the tape for advancing the tape. In an embodiment, feeder holes170are used to advance the film through various processing techniques. For example, feeder holes170could be used to control the flow of the film through a metal deposition process by using a wheel with teeth (i.e., sprockets) designed to fit in feeder holes170. The sprocket could stop the film for a prescribed time during the processing of one area of the film. The wheel could then advance the film such that the next area of the film to be processed is in the correct position for processing. In an embodiment, the reel could be loaded into a chamber with a controlled atmosphere, processed, and removed from the chamber.

Referring toFIGS. 1C and 1D, in an embodiment, a metal pattern140is deposited or printed on film110. In an embodiment, the metal is deposited as a blanket over the surface of film110and a portion of the metal is removed to form pattern140. For example, a photolithography/etching process could be used to form the metal pattern. In an embodiment, antennas132and130are printed or deposited as part of metal pattern140. In an embodiment, parts of metal pattern140that are not part of antennas132and130are present for other functions, such as electrostatic discharge protection or testing of the device. For example, electronic probes could contact various portions of metal pattern140to ensure that there are no conductivity breaks in the pattern.

Referring toFIGS. 1E and 1F, in an embodiment, holes125,127, and120are created in film110. For example, the holes could be cut, punched, or etched into film110. In an embodiment, hole120is sized for the placement of an electronic component. In an embodiment, holes125and127are created to size a dimension190.

Referring toFIGS. 1G and 1H, in an embodiment, an electronic device150is placed in hole120. In an embodiment, electronic device150is soldered to a portion of metal pattern140. For example, electronic device could be soldered to antennas130and132. The soldering could form a mechanical bond as well as an electrical connection. In an embodiment, electronic device150is bonded to film110. In an embodiment, the one or more electronic devices are bonded to the tape (film). In an embodiment, the one or more electronic devices comprises a two-chip stack. In an embodiment, the two-chip stack comprises two chips connected using flip chip bonding. For example, an epoxy could be used to bond electronic device150in hole120. In another example, solder could be used to bond the electronic device150to antennas130and132.

Referring toFIGS. 1I and 1J, in an embodiment, film110is cut along lines180and182such that a component portion115is separated from the film110. In an embodiment, component portion115includes the electronic device150and at least part of antennas132and130. In an embodiment, cut lines180and182are placed such that they align up with the edges of a ribbon160. In an embodiment, cut lines180and182are placed such that they determine a length of antennas132and130by adjusting dimension165. In an embodiment, the ribbon is a polyimide film. In an embodiment, the ribbon is any long and narrow object. For example, the ribbon could be a strand, a string, a fiber, a cloth, a metal fiber, a filament, an oval shaped string, or a film. In an embodiment, film110is moved from a first reel to a second reel during processing. In an embodiment, ribbon160is advanced from a first reel to a second reel during processing. In an embodiment, the advancement of ribbon160is used to determine the spacing of component portion115and any similar component portions attached to ribbon160. In an embodiment, an advancement of the ribbon during the bonding determines a spacing of the one or more component portions on the ribbon. Also, the reel-to-reel processing movement of ribbon160can be perpendicular (or any other angle) to the reel-to-reel processing movement of film170. To this end, the reel-to-reel speed of ribbon160relative to the reel-to-reel speed of film170determines the pitch placement of component portion115onto the ribbon160. In an embodiment, the method further includes transferring the ribbon from a first reel to a second reel.

Referring toFIGS. 1K and 1L, in an embodiment, component portion115is attached to ribbon160. For example, component portion115could be epoxied, molded, or embossed onto ribbon160. In an embodiment, multiple component portions similar to component portion115are attached to ribbon160. In an embodiment, portions of film110that are not component portion115are not attached to ribbon160. In an embodiment, ribbon160is a section of a larger ribbon. In an embodiment, ribbon160is processed using a reel to reel process used in conjunction with the reel to reel process used for processing film110. In an embodiment, multiple components (such as component portion115) are attached to ribbon160. For example, in an assembly process, multiple components, such as component portion115, could be transferred to ribbon160during processing with either substantially the same spacing that they are produced on film210or spaced according to need during processing by controlling the reel-to-reel ribbon160speed relative to the reel-to-reel film110speed.

In an embodiment, component portions similar to component portion115contain multiple electronic devices similar to electronic device150. For example, a component portion may contain two electrical devices, electronic device150attached to antenna132and130and an electrical device (not shown) not directly attached to antenna132and130. In an embodiment, the antennas can be oriented in any desired direction with respect to the ribbon160. For example, the antennas132and130could be perpendicular to ribbon160as shown, or there could be one or more antennas at angles other than perpendicular to the ribbon. In an embodiment, there are multiple antennas at multiple angles with multiple lengths. For example, the electronic device150could have an antenna off of each side, each antenna having a different length. In an embodiment, the length of one or more antennas is selected based on expected operational wavelengths of the electronic device.

Referring toFIGS. 2A and 2B, in an embodiment, antenna232, and230are to the length of film210. Thus, the lengths of antennas232and232are determined by the cutting of holes232and230and independent of cut lines280and282.

Referring toFIGS. 2C and 2D, in an embodiment, a component portion215of film210is bonded to a ribbon260such that a printed metal240side of component portion215is towards ribbon260. In an embodiment, antennas230and232are sandwiched between component portion215and ribbon260. For example, epoxy could be used to bind component portion215to ribbon260such that the majority of the antennas are not exposed. Cut lines280and282can define a dimension265of component portion215. In an embodiment, bonding an electronic device250in a hole is done at the same time as bonding component portion215to ribbon260.

Referring toFIG. 3, in an embodiment, station300is a reel to reel processing station. In an embodiment, station300depicts one portion of a larger processing system, where reel310is attached to station300for processing before or after the film330is processed at a different station. In an embodiment, a reel310is placed in station300for processing. During processing, the film is moved from reel310to reel320after going through processing points340,350,360, and370. In an embodiment, station300has more or fewer processing points than depicted. In an embodiment, each processing point340,350,360, or370is selected from a group consisting of creating holes, depositing or printing metal, attaching a chip, soldering, cutting film330, or bonding a component portion of film330to a ribbon.

Referring toFIGS. 4A and 4B, in an embodiment, testing pads490and495are produced during the depositing of conductive pattern440. In an embodiment, the testing pads490and495are used to test electronic device450through antennas430and432. In and embodiment, more test pads are produced on the tape. For example, the additional test pads could facilitate functionality testing on tape. For example, test pads can also provide electrical access for burn-in or programming of fuses, EPROMS, EEPROMS, FLASH or any other type of write once or write many times non-volatile memory. In an embodiment, a hole for electronic device450is created in a first step, and holes425and427are created in a second step. In an embodiment, the creation of holes425and427removes testing pads490and495from film410.

Referring toFIG. 5, in an embodiment, an increment567of one or more component portions516,517, and518on a ribbon560is dictated by the desired application. For example, if currency is a desired application, increment567of one or more component portions516,517, and518on a ribbon could be the width of the currency such that one component portion516,517, or518is on every piece of currency after ribbon560is incorporated into the currency. Similarly, increment567could be half the width of the currency if two component portions516,517, or518are to be included on every piece of currency. In an embodiment, an increment569of component portions (such as component portions516,517, and518) on tape510is dictated by processing parameters (such as the spacing of components required for the final product) of tape510. In an embodiment, tape510and ribbon560are advanced in increments. For example, tape510is advanced forward by increment569, ribbon560is advanced by increment567, a component portion (such as component portion517) is cut from tape510, leaving hole585on tape510, and bonded to ribbon560. Tape510is advanced by increment569, ribbon560is advanced by increment567again and a new component portion (such as component portion518) is cut from tape510, leaving a hole (where component portion518is shown) on tape510, and bonded to ribbon560. In an embodiment, an area529is where a component portion519will be bonded after component portion519is removed from tape510. In an embodiment, an increment is a spacing.

Referring toFIGS. 6A and 6B, in an embodiment, a ribbon660with one or more component portions is incorporated into a piece of paper611. In an embodiment, ribbon660is woven into the piece of paper611. For example, solid rectangles of ribbon660show the portions of ribbon660that are visible above piece of paper611. Dashed portions of ribbon660show the area of660that is not visible on the front side of the piece of paper. In an embodiment, a dashed line of ribbon660inFIG. 6Bshows that piece of paper is not visible from a surface of piece of paper611. In an embodiment, ribbon660may be partially visible from both sides of piece of paper611. In an embodiment, ribbon660may be partially visible from one side of piece of paper611and not visible from the other side of piece of paper611. In an embodiment, ribbon660may be substantially obscured from sight on both sides of piece of paper611. For example, the ribbon could be integrated into a bill similar to how a security strip is integrated into the United States $100 bill. In an embodiment, not visible does not necessarily mean that scrutinizing the bill would not reveal ribbon the presence of660, but instead indicates that ribbon660generally blends into paper611.

Referring toFIG. 7, in an embodiment, a method700of the present invention is configured to perform an operation710of patterning metal on a tape, an operation720of creating one or more holes in the tape, an operation730of attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, an operation740of electrically connecting the one or more electronic devices to the patterned metal, an operation750of cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions have at least one electronic device, among the one or more electronic devices, attached to the patterned metal, and an operation760of bonding the one or more component portion to a ribbon. In an embodiment, the threshold is a desired thickness of the component portion. For example, where the profile of the tape and the one or more electronic devices is less than a threshold, the threshold is a desired thickness of the component portion as determined by the final product the component portion/ribbon will be attached to.

Referring toFIG. 8, in an embodiment, a method800of the present invention is configured to perform an operation810of patterning metal on a tape, an operation820of creating one or more holes in the tape, an operation830of attaching one or more electronic devices to the tape in the one or more holes such that a profile of the tape and the one or more electronic devices is less than a threshold, an operation840of electrically connecting the one or more electronic devices to the patterned metal, and an operation850of cutting the tape, resulting in one or more component portions of the tape and one or more excess portions of the tape, where the one or more component portions have at least one electronic device, where the patterned metal forms one or more antennas, where the cutting determines a length of the one or more antennas, among the one or more electronic devices, attached to the patterned metal. In an embodiment, the patterned metal forms an antenna.