FLEXIBLE POWERED CARDS AND DEVICES, AND METHODS OF MANUFACTURING FLEXIBLE POWERED CARDS AND DEVICES

A flexible device, such as a powered card or processor based system, may include a flexible assembly. The flexible assembly may include a die adhered to a flexible substrate (e.g., a PCB) by a flexible adhesive. The die may be stacked with other dies that may be adhered to each other with a flexible adhesive. A conductive pad may be between a flexible substrate and a flexible adhesive. Bond wires may interconnect one or more dies and the flexible substrate via bond pads. In a stacked die configuration, the dies may be thinned using a thinning and/or a polishing process. Such thinned dies may be flexible. The flexible assembly may be flexibly encapsulated.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows card100. Referring toFIG. 1, a card100may include, for example, a dynamic number that may be entirely, or partially, displayed using a display (e.g., display106). A dynamic number may include a permanent portion such as, for example, permanent portion104and a dynamic portion such as, for example, a number displayed by display106. Card100may include a dynamic number having permanent portion104and permanent portion104may be incorporated on card100so as to be visible to an observer of card100. For example, labeling techniques, such as printing, embossing, laser etching, etc., may be utilized to visibly implement permanent portion104.

Card100may include a second dynamic number that may be entirely, or partially, displayed via a second display (e.g., display108). Display108may be utilized, for example, to display a dynamic code such as a dynamic security code. Card100may also include third display122that may be used to display, for example, graphical information, such as logos and barcodes. Third display122may also be utilized to display multiple rows and/or columns of textual and/or graphical information.

Persons skilled in the art will appreciate that any one or more of displays106,108, and/or122may be implemented as a bi-stable display. For example, information provided on displays106,108, and/or122may be stable in at least two different states (e.g., a powered-on state and a powered-off state). Any one or more of displays106,108, and/or122may be implemented as a non-bi-stable display. For example, the display is stable in response to operational power that is applied to the non-bi-stable display. Other display types, such as LCD or electrochromic, may be provided as well.

Other permanent information, such as permanent information120, may be included within card100, which may include user specific information, such as the cardholder's name or username. Permanent information120may, for example, include information that is specific to card100(e.g., a card issue date and/or a card expiration date). Information120may represent, for example, information that includes information that is both specific to the cardholder, as well as information that is specific to card100.

Card100may accept user input data via any one or more data input devices, such as buttons110-118. Buttons110-118may be included to accept data entry through, for example, mechanical distortion, contact, and/or proximity. Buttons110-118may be responsive to, for example, induced changes and/or deviations in light intensity, pressure magnitude, or electric and/or magnetic field strength. Such information exchange may then be determined and processed by a processor of card100as data input.

Card100may be flexible. Card100may, for example, contain hardware and/or software (e.g., flex code stored in memory152) that when executed by a processor of card100may detect when card100is being flexed. Flex code may be, for example, processor executable applications and/or may be one or more application specific integrated circuits, that may detect a change in operation of card100based on the flexed condition of card100and may alter functions of card100based on the detected change in operation.

According to at least one example embodiment, a processor of card100may receive a signal from a distortion detection element indicating an amount of flexure of card100. A distortion detection element may be, for example, a microelectricalmechanical system (MEMS), such as a MEMS capacitor. A degree of flexure may be determined according to a signal from the MEMS (e.g., a signal representing a capacitance of the MEMS capacitor). Light Source123may provide an indication to a user of the level of flexure of card100based on the MEMS signal. For example, light source123may be a multicolored light emitting diode (LED) emitting light during flexure of card100. A color of light source123may indicate whether a degree of flexure may result in damage to card100(e.g., green for acceptable flexure, yellow for borderline flexure and red for potentially damaging flexure).

FIG. 1shows architecture150, which may include one or more processors (e.g., processor154which may be a plurality of stacked processors). Processor154may be configured to utilize external memory152, internal memory of processor154, or a combination of external memory152and internal memory for dynamically storing information, such as executable machine language (e.g., flex code), related dynamic machine data, and user input data values. Processor154may, for example, execute code contained within memory152to detect when a card (e.g., card100ofFIG. 1) is being flexed. The executed code may, for example, change the operation of a card (e.g., card100ofFIG. 1) based on the detected change in operation and/or indicate a flexure state to a user (e.g., light source123ofFIG. 1).

Processor154may be a single die, or a combination of two or more die stacked on top of one another. A die may be a thin die attached to a thin and flexible substrate and/or to another die. For example, stacked dies may be flexibly adhered to a mechanical carrier (e.g., a flexible printed circuit board (PCB)), and to each other, using flexible, non-anaerobic, low ionic adhesive. A low ionic adhesive may be an adhesive that includes relatively little (e.g., less than about 20 ppm) or no ionic species that may affect device operation (e.g., migratory species in semiconductor devices) and/or that acts as a barrier to such ionic species.

In the case of a stacked arrangement, a bottom die may exhibit a larger diameter than a die stacked on top of the bottom die. Accordingly, for example, interconnections (e.g., wire bonds) may be placed from one die to another die and/or from each die to the underlying PCB. According to some example embodiments, processor154may be a flip-chip combination, where die-to-die and/or die-to-PCB connections may be established using through-die connections and associated interconnections (e.g., a ball grid array (BGA)) with a flexible adhesive between bumps. In so doing, for example, each of the stacked die may exhibit the same or different diameters.

A flexible adhesive may mechanically connect surfaces, or mechanically and electrically connect surfaces, as desired. For example, a conductive, flexible adhesive may electrically connect a die to a conductive pad of a flexible substrate for bulk or body biasing of the die. As another example, an insulating, flexible adhesive may electrically isolate components of a die-to-substrate interface (e.g., BGA isolation).

One or more of the components shown in architecture150may be configured to transmit information to processor154and/or may be configured to receive information communicated by processor154. For example, one or more displays156may be coupled to receive data from processor154. The data received from processor154may include, for example, at least a portion of dynamic numbers and/or dynamic codes.

One or more displays156may be, for example, touch sensitive, signal sensitive and/or proximity sensitive. For example, objects such as fingers, pointing devices, and the like may be brought into contact with displays156, or in proximity to displays156. Objects such as light and/or sound emitting device may be aimed at displays156. Detection of signals, object proximity or object contact with displays156may be effective to perform any type of function (e.g., communicate data to processor154). Displays156may have multiple locations that are able to be determined as being touched, or determined as being in proximity to an object. As one non-limiting example, display156may be a thin film transistor (TFT) array (e.g., semiconductor oxide TFT array) configured to receive and emit light.

Input and/or output devices may be implemented on architecture150. For example, integrated circuit (IC) chip160(e.g., an EMV chip) may be included within architecture150, that may communicate information to a chip reader (e.g., an EMV chip reader). Radio frequency identification (RFID) module162may be included within architecture150to enable the exchange of information with an RFID reader/writer.

Other input and/or output devices may be included within architecture150, for example, to provide any number of input and/or output capabilities. For example, input and/or output devices may include an audio and/or light device operable to receive and/or communicate audible and/or light-based information. Input and/or output devices may include a device that exchanges analog and/or digital data using a visible data carrier. Input and/or output devices may include a device, for example, that is sensitive to a non-visible data carrier, for example, an infrared data carrier or an electromagnetic data carrier.

Persons skilled in the art will appreciate that a card (e.g., card100ofFIG. 1) may, for example, include components (including other die components) on a mechanical carrier other than processor154. RFID162, IC chip160, memory153, a charge coupled device (CCD) (not shown), a semiconductor sensor (e.g., a complementary oxide semiconductor (CMOS) sensor) (not shown), a transducer (not shown), an accelerometer (not shown) and/or flex detector168may, for example, each be flexibly adhered with a flexible adhesive to a flexible substrate, and/or to another component.

Flex detector168may detect flexure of a device (e.g., card100). For example, flex detector168may include a distortion detection element operable to detect an amount of flexure of a device. Flex detector168may be, for example, a MEMS detector, piezoelectric element, detection circuitry, and/or the like.

Two or more device components may be stacked and interconnected. For example, two or more die may be flexibly adhered to each other and interconnected via wire-bonding, ball grid array, or other connection types. Accordingly, for example, surface area on the PCB may be conserved by adding components in vertical fashion rather than adding components laterally across the surface area of the PCB.

Persons skilled in the art will further appreciate that a card (e.g., card100ofFIG. 1) may, for example, be a self-contained device that derives its own operational power from one or more batteries158. One or more batteries158may be included, for example, to provide operational power for a period of time (e.g., approximately 2-4 years). One or more batteries158may be included, for example, as rechargeable batteries.

Electromagnetic field generators170-174of dynamic magnetic stripe communications device176may be included within architecture150to communicate information to, for example, a read-head of a magnetic stripe reader via, for example, electromagnetic signals. For example, electromagnetic field generators170-174may be included to communicate one or more tracks of electromagnetic data to read-heads of a magnetic stripe reader. Electromagnetic field generators170-174may include, for example, a series of electromagnetic elements. Each electromagnetic element may be implemented as a coil encircling one or more materials (e.g., a magnetic material and/or a non-magnetic material). Additional materials may be outside the coil (e.g., a magnetic material and/or a non-magnetic material).

Electrical excitation by processor154of one or more coils of one or more electromagnetic elements via, for example, driving circuitry164may generate electromagnetic fields from the one or more electromagnetic elements. One or more electromagnetic field generators170-174may be utilized to communicate electromagnetic information to, for example, one or more read-heads of a magnetic stripe reader.

Timing aspects of information exchange between architecture150and the various I/O devices implemented within architecture150may be determined by processor154. Detector166may be utilized, for example, to sense the proximity and/or actual contact, of an external device, which in turn, may trigger the initiation of a communication sequence. The sensed presence and/or touch of the external device may then be communicated to a controller (e.g., processor154), which in turn may direct the exchange of information between architecture150and the external device. The sensed presence and/or touch of the external device may be effective to, for example, determine the type of device or object detected.

For example, the detection may include the detection of a read-head of a magnetic stripe reader. In response, processor154may activate one or more electromagnetic field generators170-174to initiate a communications sequence with, for example, one or more read-heads of a magnetic stripe reader. The timing relationships associated with communications between one or more electromagnetic field generators170-174and one or more read-heads of a magnetic stripe reader may be based on a detection of the magnetic stripe reader.

Persons skilled in the art will appreciate that processor154may provide user-specific and/or card-specific information through utilization of any one or more of buttons110-118, RFID162, IC chip160, electromagnetic field generators170-174, and/or other input and/or output devices.

Die component220may include, for example, a thin monocrystalline semiconductor chip in packaged or unpackaged form. Die component220may be, for example, a processors, ASIC, mixed-signal device, transistor device, and any other device. Die component220may be thinned to increase flexibility and/or decrease thickness (e.g., by a grinding or polishing process). A thinning process may reduce a thickness of die component220to a thickness of about 20 microns to 0.00025 inches. A thickness of die component220in a stacked configuration may be, for example, about 0.00025 inches to 0.008 inches (e.g., approximately 0.004 inches). A thickness of an unstacked die may be about 0.0018 inches to about 0.0065 inches.

Flexible substrate210may be a flexible printed circuit board (PCB) with, for example, a thickness of about 0.001 inches to about 0.003 inches (e.g., without PIC coatings). A material of flexible substrate210may include, for example, polyimide, polyester, an organic polymer thermoplastic, laminate material (e.g., FR-4), a liquid crystal polymer, a combination of these materials and/or the like.

Die cracks may be a mode of device failure during flexure. Die cracks may occur due to, for example, flexing of dies adhered to substrates, wrinkled substrates causing uneven force transfer during device flexure and/or a failure to achieve a solid cure/bond between a die and a substrate.

Die component220may be adhered to flexible substrate210by flexible adhesive250. Properties of flexible adhesive250may include no/low ionic contamination (e.g., less than about 20 ppm for anions or cations, for example, Na+, K+, Cl−, F− and the like), low modulus (e.g., about 0.2 to about 0.05 GPa at 25 degrees centigrade), high stability (e.g., a coefficient of thermal expansion of about 20 to about 100 ppm per degree centigrade) and robust glass transition properties (e.g., a TGof below about 0 degrees centigrade). Flexible adhesive250may be non-anaerobic. A non-anaerobic adhesive may be an adhesive with a bonding strength that is generally independent of oxygen contaminants at a bonding surface. Flexible adhesive250may be conductive and/or non-conductive, and may be, for example, about 0.0008 to about 0.0012 inches thick.

Flexible adhesive250may flexibly adhere die component220(or a non-die component) to flexible substrate210such that force transfer to die component220may be attenuated during bending of a device including flexible assembly200(e.g., a powered card and/or flexible mobile phone).

A material of flexible adhesive250may change physical state (e.g., change from a liquid substance to a solid substance) when cured by one or more conditions (e.g., air, heat, pressure, light, and/or chemicals) for a period of time. Flexible adhesive250may be cured, but may remain flexible, so that flexible substrate210may be flexed to exhibit either of a convex or concave shape, while returning to a substantially flat orientation once flexing ceases. Flexure of die component220and/or force transfer by flexible substrate210to die component220, may be reduced.

Mechanical and/or electrical interconnections between die component220and flexible substrate210may, for example, include bond wires230. Bond wires230may be connected to, for example, bond pads240on flexible substrate210, and bond pads240on die component220. Electrical and/or mechanical interconnections between die component220and flexible substrate210may, for example, include solder balls (not shown). Electrical and/or mechanical interconnections between die component220and flexible substrate210may, for example, include flip-chip solder balls of a ball grid array.

Bond pads240may include a conductive material. For example, bond pads240may include aluminum, nickel, gold, copper, silicon, palladium silver, palladium gold, platinum, platinum silver, platinum gold, tin, kovar (e.g., nickel-cobalt ferrous alloy), stainless steel, iron, ceramic, brass, conductive polymer, zinc and/or carbide. The conductive material of a bond pad210may be a solder, a flexible printed circuit board trace and/or the like. According to one non-limiting example embodiment, bond pads240may be a multi-layer structure (not shown) including a copper (Cu) layer on flexible substrate210, a nickel (Ni) layer on the Cu layer and a gold (Au) layer on the Ni layer.

Bond wires230may be wire bonded to bond pads240. Wire bonding may be performed using any wire bonding method. For example, wire bonding may include hand bonding, automated bonding, ball bonding, wedge bonding, stitch bonding, hybrid bonding, a combination of bonding methods and/or the like. Bond wires230may each include a same or different material. A material of a bond wire230may be the same or different from a material of a bonding pad240. Each of bond wires230may include one or more materials and/or layers.

Through-die vias may, for example, provide electrical connectivity between die component220, flexible substrate210and other components (not shown). For example, electrical signals may be communicated between die component220, flexible substrate210and other components using conductive vias that may extend through die component220.

Flexible assembly200may include encapsulant260, which may include a layer of material (e.g., a material including one or more polyurethane-based and/or silicon-based substances). A material of encapsulant260may be a substance that changes its physical state (e.g., changes from a liquid substance to a solid substance) when cured by one or more conditions (e.g., air, heat, pressure, light, and/or chemicals) for a period of time. Encapsulant260may be hardened, but may remain flexible, so that flexible assembly200may be flexed to exhibit either of a convex or concave shape, while returning to a substantially flat orientation once flexing ceases.

FIG. 3shows device300. Referring toFIG. 3, device300may, for example, be a laminated assembly including flexible substrate336, top and bottom layers of a material (e.g., polymer top and bottom layers), and components302,304and306.

Components302-306may be dies (e.g., stacked or non-stacked dies) and/or other components (e.g., a photosensitive device, a sensor, a transducer and/or an accelerometer). Components302-306may be flexibly adhered to flexible substrate336and/or encapsulated with a flexible material. The encapsulant and/or adhesive may be cured (e.g., hardened) such that device300may be rigid, yet flexible, while attenuating force transfer to components302-306during flexure.

Components302-306may be thinned components. Thinning of components302-306(e.g., via a grinding or polishing process) may increase the flexibility of components302-306and may, for example, decrease a bend radius at which damage to a component begins to occur.

When device300is flexed, an amount of force exerted on components302-308may be less than an amount of force exerted on flexible substrate336and/or outer layers of device300. When device300is flexed, an amount of flexure of components302-308may be less than an amount of flexure of flexible substrate336and/or outer layers of device300.

One or more detectors (not shown) may be placed within device300to detect an amount of flexure of device300and generate a signal in response. Based on the signal, a light source may be turned on or off, and/or operation of device300may be altered.

Device300may be flexed in direction328and/or330to bend device300into a concave orientation having minimum bend radius324. Components302-306may assume positions308-316, respectively, and flexible substrate336may assume position338, as a result of such flexing. Components302-306may be flexibly adhered to flexible substrate336, encapsulated with a flexible material and/or thinned such that flexing may not destroy the operation of components302-306, and a change in the operation of components302-306due to flexure may be reduced.

Device300may be flexed in direction332and/or334to bend device300into a convex orientation having minimum bend radius326. Components302-306may assume positions310-318, respectively, and flexible substrate336may assume position340, as a result of such flexing. Components302-306may be flexibly adhered to flexible substrate336, encapsulated with a flexible material and/or thinned such that flexing may not destroy the operation of components302-306, and a change in the operation of components302-306due to flexure may be reduced.

Die component420may include, for example, a semiconductor chip in packaged or unpackaged form. Die component420may be, for example, a processors, ASIC, mixed-signal device, thin-film transistor device, and any other device. Die component420may be thinned, for example, by a grinding or polishing process. A thinning process may reduce a thickness of die component420to a thickness of about 20 microns to 0.00025 inches. A thickness of die component420in a stacked configuration may be, for example, about 0.00025 inches to 0.008 inches (e.g., approximately 0.004 inches). Die component420may be attached to a mechanical carrier.

Flexible substrate410may be a flexible printed circuit board (PCB). A material of flexible substrate410may include, for example, polyimide, polyester, an organic polymer thermoplastic, laminate material (e.g., FR-4), liquid crystal polymer, a combination of these materials and/or the like. Conductive pad460may be on flexible substrate410, and may include one or more conductive materials. For example, conductive pad460may be a multi-layer structure (not shown) including a copper (Cu) layer on flexible substrate410, a nickel (Ni) layer on the Cu layer and a gold (Au) layer on the Ni layer.

Die component420may be adhered to conductive pad460by flexible adhesive450. Properties of flexible adhesive450may include no/low ionic contamination, low modulus, high stability and robust glass transition properties.

Flexible adhesive450may flexibly adhere die component420(or a non-die component) to conductive pad460such that force transfer may be attenuated during bending of a device including flexible assembly400(e.g., a flexible computing device). Flexible adhesive450may be conductive and/or non-conductive. For example, die component420may be a body/bulk biased component conductively adhered to conductive pad460by a conductive flexible adhesive450.

A material of flexible adhesive450may change physical state (e.g., change from a liquid substance to a solid substance) when cured by one or more conditions (e.g., air, heat, pressure, light, and/or chemicals) for a period of time. Flexible adhesive450may be cured, but may remain flexible, so that flexible substrate410may be flexed to exhibit either of a convex or concave shape, while returning to a substantially flat orientation once flexing ceases. Flexure of die component420and/or force transfer by flexible substrate410to die component420, may be reduced.

Mechanical and/or electrical interconnections between die component420and flexible substrate410may, for example, include bond wires430. Bond wires430may be connected to, for example, bond pads440on flexible substrate410and die component420. Electrical and/or mechanical interconnections between die component420and flexible substrate410may, for example, include solder balls (not shown). Electrical and/or mechanical interconnections between die component420and flexible substrate410may, for example, include flip-chip solder balls of a ball grid array.

Through-die vias may, for example, provide electrical connectivity between die component420, flexible substrate410and other components (not shown). For example, electrical signals may be communicated between die component420, flexible substrate410and other components using conductive vias that may extend through die component420, and may be electrically interconnected via solder balls of a ball grid array. Flexible assembly400may include an encapsulant (not shown).

FIG. 5shows a flexible assembly500of a flexible device (e.g., a flexible processing device). Referring toFIG. 5, flexible assembly500may, for example, include a flexible substrate510, stacked components520and560(e.g., stacked dies), bond wires530,533and535, bond pads540, and flexible adhesives550and570.

Flexible assembly500may include stacked components520and560(e.g., stacked dies). Stacked components520and560may, for example, include one or more processors, ASICs, mixed-signal devices, transistor devices, light sensing devices, wafer sensors, transducers, accelerometers and the like. Stacked components520and560may, for example, be thinned (e.g., via a grinding or polishing process). Such a thinning process may reduce a thickness of stacked components520and560to a thickness of about 20 microns to 0.010 inches. A thickness of a component (e.g., a die) may be thinned to about 0.00025 inches to 0.008 inches (e.g., approximately 0.004 inches).

Flexible substrate510may be, for example, a flexible printed circuit board (PCB). A material of flexible substrate510may include, for example, polyimide, polyester, an organic polymer thermoplastic, laminate materials (e.g., FR-4), liquid crystal polymer, a combination of these materials and/or the like.

Stacked component520may or may not be a flexible component, and may be adhered to flexible substrate510by flexible adhesive550. Flexible adhesive550may be a flexible, non-anaerobic, low ionic, flexible adhesive. Properties of flexible adhesive550may include no/low ionic contamination, low modulus, high stability and robust glass transition properties. Stacked component560may or may not be a flexible component, and may be adhered to stacked component520by flexible adhesive570. Flexible adhesive570may be the same adhesive as, or a different adhesive from, flexible adhesive550, and may be a flexible, non-anaerobic, low ionic, flexible adhesive.

Mechanical and/or electrical interconnections between stacked components520and560, and flexible substrate510may, for example, include bond wires530and533. Mechanical and/or electrical interconnections between stacked component520and stacked component560may, for example, include bond wires535.

Stacked component560may be of a smaller diameter as compared to stacked component520. Bond wire connections between stacked components520and560, between stacked component520and flexible substrate510, and between component560and flexible substrate510may be facilitated. A plan view (not shown) of component520, component560, and flexible substrate510may, for example, illustrate that bond pads540associated with bond wires530,533and535may be staggered so as to substantially reduce a possibility of shorting bond wires to interconnect pads not associated with such bond wires.

Electrical and/or mechanical interconnections between stacked component520, stacked component560and flexible substrate510may, for example, include solder balls (not shown), conductive pads (not shown) and/or the like. Accordingly, for example, stacked components520and560may be of the same, or different, diameters. Persons of ordinary skill in the art in possession of example embodiments will appreciate that althoughFIG. 5shows two stacked components, example embodiments are not so limited. Any number of components may be stacked and flexibly adhered.

Through-component vias (e.g., through-die vias) may, for example, provide electrical connectivity between any one or more of stacked components520and560, and flexible substrate510. For example, electrical signals may be communicated between stacked components520and560, and between any one or more of stacked components520and560, and flexible substrate510, using conductive vias that may extend through components520and560.

Flexible assembly500may include a flexible encapsulant (not shown). Accordingly, for example, flexible assembly500may be cured, but may remain flexible, so that a flexible device including flexible assembly500may be flexed to exhibit either a convex or concave shape, while returning to a substantially flat orientation once flexing ceases, and reducing and/or eliminating damage to components.

FIG. 6shows a flow diagram of process sequences. Referring toFIG. 6, step611of sequence610may include, for example, depositing a flexible, non-anaerobic, low ionic adhesive on a flexible substrate. For example, the material of the flexible adhesive may be deposited as a glob top material on the flexible substrate and/or by selectively depositing the flexible adhesive on the flexible substrate. According to some example embodiments, the flexible adhesive may be deposited onto a die and not the flexible substrate, or onto the die and the flexible substrate.

A die may be placed onto the flexible substrate (e.g., using pick and place) as in step612. The flexible adhesive between the flexible substrate and the die may not extend beyond the edges of the die after placement. The die may be connected to the flexible substrate via bond pads and wires, and/or solder bumps as in step613.

Step621of sequence620may, for example, include depositing a first flexible, non-anaerobic, low ionic adhesive onto a flexible substrate. For example, the material of the first flexible adhesive may be deposited as a glob top material on the flexible substrate and/or by selectively depositing the first flexible adhesive onto the flexible substrate. According to some example embodiments, the first flexible adhesive may be deposited onto a first die and not the flexible substrate, and/or onto the first die and the flexible substrate.

A first die may be placed onto the flexible substrate (e.g., using pick and place) as in step623. The flexible adhesive between the flexible substrate and the first die may not extend beyond the edges of the die after placement.

A second flexible, non-anaerobic, low ionic adhesive may be deposited onto the first die as in step625. For example, the material of the second flexible adhesive may be deposited as a glob top material onto an opposite side of the first die from the first flexible adhesive and/or by selectively depositing the second flexible adhesive onto the opposite side. According to some example embodiments, the second flexible adhesive may be deposited onto a second die and not the first die, and/or onto the first die and the second die.

A second die, of a smaller width than a width of the first die, may be placed onto the first die (e.g., using pick and place), within the footprint of the first die, as in step627. The flexible adhesive between the first die and the second die may not extend beyond the edges of the second die after placement. The first die, second die and flexible substrate may be interconnected via bond pads and wires, and/or solder bumps as in step629.

According to some example embodiments, stacked dies may be of reduced thickness (e.g., by utilizing a grinding and/or polishing process) to accommodate stacking. For example, a die containing a processor may be placed onto the flexible substrate and another die containing an ASIC may be stacked on top of the die containing the processor. Yet another die (e.g., a die containing mixed-mode electronics or other circuitry) may be stacked onto the die containing the ASIC to yield a three-die stack. Accordingly, for example, by stacking die, surface area of the PCB may be conserved. Such a stacked-die arrangement may be used to produce devices, such as a powered card, a telephonic device (e.g., a cell phone), an electronic tablet, a watch, or any other device. Such a stacked-die arrangement may be encapsulated between two layers of laminate material (e.g., polymer material), injected with an encapsulant, and hardened to produce a rigid, yet flexible device.

Each of the stacked die may be interconnected to each other and/or one or more of the stacked die may be interconnected to signal traces on the flexible substrate. By way of example, such interconnections may be implemented via wire bonds, whereby wires may be attached to interconnect pads of each die. Such wire bonding may be facilitated by placing larger diameter die at the bottom of the stack while placing smaller diameter die in order of decreasing diameter on top of the larger diameter die. In addition, interconnect pads may be staggered (e.g., no interconnect pads of any die or substrate may be directly adjacent to one another in a plan view) to reduce a possibility that wire bonds may make electrical contact with interconnect pads not intended for that wire bond. According to at least one example embodiment, for example, each stacked die may be substantially the same diameter and may be interconnected to each other and the PCB using through-die vias and ball grid array interconnections.

Step631of sequence630may, for example, include depositing a flexible, non-anaerobic, low ionic adhesive onto a conductive pad of a flexible substrate. For example, the material of the flexible adhesive may be deposited as a glob top material on the conductive pad and/or by selectively depositing the flexible adhesive on the conductive pad. According to some example embodiments, the flexible adhesive may be deposited onto a die and not the conductive pad, and/or onto the die and the conductive pad.

A die may be placed onto the conductive pad of the flexible substrate (e.g., using pick and place) as in step633. The flexible adhesive between the conductive pad and the die may not extend beyond the edges of the die after placement. The die may be connected to the flexible substrate away from the conductive pad via bond pads and wires, and/or solder bumps as in step635.

Persons skilled in the art will appreciate that the present invention is not limited to only the example embodiments described. Instead, the present invention more generally involves dynamic information and the exchange thereof. Features described with respect to one example embodiment may be utilized in a different example embodiment. Persons skilled in the art will also appreciate that the apparatus of the present invention may be implemented in other ways than those described herein. All such modifications are within the scope of the present invention, which is limited only by the claims that follow.