Patent Publication Number: US-10319890-B2

Title: Systems for adhesive bonding of electronic devices

Description:
RELATED APPLICATIONS 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/107,660, filed Jan. 26, 2015, and U.S. Provisional Patent Application No. 62/198,415, filed Jul. 29, 2015, the entire disclosure of each of which is hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     In various embodiments, the present invention generally relates to electronic device mounting, and more specifically to the mounting of electronic devices via pressure-activated adhesives. 
     BACKGROUND 
     A number of attachment methods may be utilized to attach and electrically connect a semiconductor die to a package or directly to a substrate or to attach a packaged semiconductor device to a substrate or printed circuit board. Several common methods include wire bonding, solder, adhesive, conductive adhesive, and anisotropic conductive adhesive (ACA). An ACA is a material that enables electrical coupling in one direction (e.g., vertically between a device contact and a substrate contact), but prevents it in other directions (e.g., horizontally between contacts on a device or between contracts on a substrate). ACA may be utilized in various forms, for example a paste, gel, liquid, or film. 
     There are several approaches to packaging of semiconductor dies. These include mounting the die on a lead frame, either with contacts on the semiconductor die facing up (where the contact pads on the die are typically electrically coupled to the package contacts through wire bonds), or in a flip-chip configuration, in which the contacts on the semiconductor die are facing down and may be electrically coupled to the package contacts more or less directly, for example using solder, conductive adhesive, or ACA. Wire bonding is typically more expensive than flip-chip mounting, and in some configurations may introduce a higher thermal resistance than the flip-chip configuration. 
     Packages are typically mounted to a substrate or circuit board using solder, for example using a reflow solder process. Semiconductor dies may be directly attached to a substrate or circuit board, without a traditional package, for example using solder or conductive adhesive or ACA. In particular, ACA has been widely used in the attachment of chips to RFID substrates, and has recently been developed for use with LEDs, as detailed in U.S. patent application Ser. No. 13/171,973, filed on Jun. 29, 2011 (the &#39;973 application), U.S. patent application Ser. No. 13/784,417, filed on Mar. 4, 2013, and U.S. patent application Ser. No. 13/949,546, filed on Jul. 24, 2013, the entire disclosure of each of which is incorporated herein by reference. 
     ACAs have a number of potential advantages over solder, including the ability to use aluminum rather than copper traces, which may result in reduced cost and the ability to manufacture using a roll-to-roll configuration. High-volume tools for RFID manufacture using ACA are commercially available, for example from Muhlbauer in Roding, Germany. 
     As known in the art, an ACA typically features an adhesive matrix, e.g., an adhesive or epoxy material, containing “particles” (e.g., spheres or particles with other shapes) of a conductive material or of an insulating material coated with a conductive material (such as metal).  FIG. 1A  depicts a typical schematic of the connection of an electronic device to a substrate via ACA. As shown, an electronic device  105  having multiple contacts  110  has been adhered and electrically connected to conductive traces  160  disposed over a substrate  120  of a circuit board  165  (circuit board  165  includes substrate  120  and conductive traces  160 ; in some embodiments circuit board  165  may also include one or more components  105  and other elements) via an ACA  130 . ACA  130  is typically composed of an adhesive matrix  140  containing a dispersion of particles  150  that are at least partially conductive. In some configurations, the use of ACA may require the use of stud bumps  170 ; however, these may not be required, for example as shown in  FIG. 1B  and described in the &#39;973 application. It should be noted that other techniques involving ACAs are possible, and the present invention is not limited by the particular mode of operation of the ACA. 
     Most ACAs are pressure-activated, and thus require application of pressure and temperature to cure the ACA, forming a permanent electrical and/or mechanical connection. The temperature and pressure are typically applied using a thermode, which provides a means to apply a force and heat to a desired temperature. In high-volume manufacture, multiple thermodes are activated simultaneously over a portion of the substrate, curing multiple electronic devices simultaneously.  FIG. 1C  shows a schematic of a thermode configuration that includes bottom and top thermodes  181  and  182  respectively. The thermodes typically apply pressure and heat to device  183  directly in the case of thermode  182  and through substrate  180  (substrate  180  may also include conductive traces and other elements, not shown for clarity in  FIG. 1C , that may affect or hinder the flow of heat to the ACA) in the case of thermode  181 . One issue with this approach is that the thermode field must be reconfigured for each new design—that is, the thermodes must be re-positioned to correspond to the positions of the devices on the substrate. This change-over may be relatively time-consuming and expensive. A second issue is that there is typically a one-to-one correspondence between the number of devices and the number of thermodes required in a given area, i.e., there typically needs to be one thermode for each device within the thermode field area. For systems having very high component counts, this means the curing system must have a very large number of thermodes, which increases cost and configuration time. 
     A third issue with this approach is that the thermodes have a minimum spacing, determined by the actual thermode size and wiring to the thermodes, which may be larger than the desired spacing between devices on the substrate. This may make it impossible to cure both devices  183  and  185  (see  FIG. 1C ) simultaneously, because their spacing is less than the minimum thermode spacing. This size limitation may currently be addressed in two ways. The first is to use multiple cure steps, for example curing every other device, to accommodate the thermode size limitations. This is very costly, as it requires repeating the process at least twice, and may also result in damage to the devices and/or substrate during subsequent cure steps. This is particularly onerous for roll-to-roll manufacture, in which the web would have to be run through the tool more than once. A second challenge with this approach is the possibility of pre-curing the ACA in devices adjacent to those being cured. An example of this would be the ACA for device  185  being partially or fully cured without the application of pressure from a thermode, by heat flow through substrate  180  (including the conductive traces not shown in  FIG. 1C ) from the adjacent thermodes. A second approach is to use a custom thermode system, with fixed position pins that contact each device. Such systems can have a smaller spacing, but require a custom, fixed thermode field for each design, which is expensive and takes a relatively significant time to procure. 
     In view of the foregoing, a need exists for systems and procedures enabling the low cost reliable curing of pressure-activated adhesives (such as ACAs) for various electronic devices, for example packaged devices and semiconductor dies, directly to the electrical traces of a package or to electrical traces on a substrate without the size and throughput limitations of conventional curing systems. 
     SUMMARY 
     In accordance with certain embodiments, one or more semiconductor bare-die devices and/or packaged devices such as light-emitting elements are attached to a substrate with a pressure-sensitive adhesive (e.g., a conductive adhesive or an ACA). The adhesive is activated for all devices substantially simultaneously via fluid pressure applied to a flexible membrane positioned over the devices. The adhesive may be cured during and/or after application of the fluid pressure via application of, e.g., heat. 
     As utilized herein, the term “light-emitting element” (LEE) refers to any device that emits electromagnetic radiation within a wavelength regime of interest, for example, visible, infrared or ultraviolet regime, when activated, by applying a potential difference across the device or passing a current through the device. Examples of light-emitting elements include solid-state, organic, polymer, phosphor-coated or high-flux LEDs, laser diodes or other similar devices as would be readily understood. The emitted radiation of an LEE may be visible, such as red, blue or green, or invisible, such as infrared or ultraviolet. An LEE may produce radiation of a continuous or discontinuous spread of wavelengths. An LEE may feature a phosphorescent or fluorescent material, also known as a light-conversion material, for converting a portion of its emissions from one set of wavelengths to another. In some embodiments, the light from an LEE includes or consists essentially of a combination of light directly emitted by the LEE and light emitted by an adjacent or surrounding light-conversion material. An LEE may include multiple LEEs, each emitting essentially the same or different wavelengths. In some embodiments, a LEE is an LED that may feature a reflector over all or a portion of its surface upon which electrical contacts are positioned. The reflector may also be formed over all or a portion of the contacts themselves. In some embodiments, the contacts are themselves reflective. Herein the term “reflective” is defined as having a reflectivity greater than 65% for a wavelength of light emitted by the LEE on which the contacts are disposed unless otherwise defined. In some embodiments, an LEE may include or consist essentially of an electronic device or circuit or a passive device or circuit. In some embodiments, an LEE includes or consists essentially of multiple devices, for example an LED and a Zener diode for static-electricity protection. In some embodiments, an LEE may include or consist essentially of a packaged LED, i.e., a bare LED die encased or partially encased in a package. In some embodiments, the packaged LED may also include a light-conversion material. In some embodiments, the light from the LEE may include or consist essentially of light emitted only by the light-conversion material, while in other embodiments the light from the LEE may include or consist essentially of a combination of light emitted from an LED and from the light-conversion material. In some embodiments, the light from the LEE may include or consist essentially of light emitted only by an LED. 
     In one embodiment, an LEE includes or consists essentially of a bare semiconductor die, while in other embodiments an LEE includes or consists essentially of a packaged LED. In some embodiments, LEE may include or consist essentially of a “white die” that includes an LED that is integrated with a light-conversion material (e.g., a phosphor) before being attached to the light sheet, as described in U.S. patent application Ser. No. 13/748,864, filed Jan. 24, 2013, or U.S. patent application Ser. No. 13/949,543, filed Jul. 24, 2013, the entire disclosure of each of which is incorporated by reference herein. 
     In an aspect, embodiments of the invention feature an apparatus for bonding a plurality of electronic components each to a connection point on a substrate via an adhesive. The apparatus includes or consists essentially of a platform for supporting the substrate, a membrane for covering the plurality of electronic components, a source of pressure for urging the membrane against the plurality of electronic components, whereby pressure is applied between each electronic component and its corresponding connection point, and a source of energy for at least partially curing the adhesive. 
     Embodiments of the invention may include one or more of the following in any of a variety of combinations. One or more portions, or even all, of the platform may be substantially rigid. The source of pressure may include, consist essentially of, or consist of a source of fluid pressure. The membrane may include, consist essentially of, or consist of a flexible membrane. The source of pressure may include, consist essentially of, or consist of a vacuum pump for inducing a negative pressure between the membrane and the substrate. The source of pressure may include, consist essentially of, or consist of a source of liquid or a source of gas. The source of energy may include, consist essentially of, or consist of a plurality of energy sources. The amount of energy emitted by each energy source may be individually controllable. At least one of the energy sources may include, consist essentially of, or consist of a heat source. The source of energy may include, consist essentially of, or consist of a plurality of heat sources disposed at least partially within and/or on the platform and/or the flexible membrane. 
     The source of energy may include, consist essentially of, or consist of a heat source. The source of energy may include, consist essentially of, or consist of an array of individually addressable heating elements. The source of pressure and/or the source of energy may be, in whole or in part, an autoclave chamber for receiving therewithin the substrate, the platform, and the membrane. The source of energy may be disposed at least partially within and/or on the platform. The platform may be substantially rigid in the sense that it resists deformation when pressure is applied by the source of pressure. The source of energy may be disposed at least partially within and/or on the membrane. The source of energy may include, consist essentially of, or consist of an ultraviolet light source. At least one of the electronic components may include, consist essentially of, or consist of a light-emitting element. At least one of the electronic components may include, consist essentially of, or consist of a light-emitting diode. The adhesive may include, consist essentially of, or consist of an anisotropic conductive adhesive and/or an isotropic conductive adhesive. 
     The apparatus may include a supply roll for supplying at least a portion of the substrate to the platform and/or a take-up roll for receiving the at least a portion of the substrate from the platform. The substrate may be flexible and may be a web extending from the supply roll to the take-up roll. The apparatus may include an adhesive dispense station for dispensing adhesive over the substrate, a component placement station for placing the plurality of electronic components over the substrate, and/or a test station for electronically and/or optically testing at least some of the electronic components. The adhesive dispense station may include or consist essentially of a reservoir for containing one or more adhesives. The reservoir may contain one or more adhesives disposed therewithin. The adhesive(s) may include, consist essentially of, or consist of an anisotropic conductive adhesive and/or an isotropic conductive adhesive. 
     In another aspect, embodiments of the invention feature a method of fabricating an electronic device. The electronic device includes or consists essentially of a plurality of electronic components each bonded to a connection point on a substrate. Each of the plurality of electronic components is positioned over a different connection point on the substrate. A pressure-activated adhesive is provided between each electronic component and its connection point (i.e., the connection point over which the electronic component is positioned). A membrane is provided over the plurality of electronic components and the substrate. A pressure is applied, via the membrane, simultaneously or substantially simultaneously between each electronic component and its connection point. The pressure-activated adhesive is cured, thereby bonding each electronic component to its connection point. 
     Embodiments of the invention may include one or more of the following in any of a variety of combinations. Applying the pressure via the membrane may include, consist essentially of, or consist of application of a fluid pressure to the membrane. A region between the membrane and the substrate and/or the plurality of electronic components may be at least partially evacuated (e.g., at least partially emptied of a fluid such as a gas or a liquid). A pressure in a region between the membrane and the substrate may be reduced. The fluid pressure may be at least partially applied to a surface of the membrane opposite the plurality of electronic components by a gas and/or by a liquid. The fluid pressure may be at least partially applied by generating at least a partial vacuum in a region between the membrane and the substrate and/or the plurality of electronic components. The fluid pressure may be at least partially applied by generating a negative pressure between the membrane and the substrate and/or the plurality of electronic components. The value of the negative pressure may be smaller than the value of a pressure on a surface of the membrane opposite the plurality of electronic components. 
     Applying the pressure via the membrane may include, consist essentially of, or consist of at least partially evacuating (i.e., evacuating at least some of a fluid from) a region between the membrane and the plurality of electronic components. The membrane may include, consist essentially of, or consist of a flexible membrane. At least a portion of the membrane may be flexible. Curing the pressure-activated adhesive may include, consist essentially of, or consist of applying heat thereto. At least one connection point may include, consist essentially of, or consist of two conductive traces defining a gap therebetween. At least one electronic component may include two spaced-apart contacts to each be bonded to one of the conductive traces. The pressure-activated adhesive may include, consist essentially of, or consist of an anisotropic conductive adhesive and/or an isotropic conductive adhesive. At least two of the electronic components may have different sizes and/or heights. The electronic components may be positioned over the substrate such that a first pair of electronic components are separated by a first spacing and a second pair of electronic components are separated by a second spacing different from the first spacing. The pressure-activated adhesive may be cured after and/or during application of the pressure. 
     At least one of the electronic components may include, consist essentially of, or consist of a bare-die light-emitting element. At least one of the electronic components may include, consist essentially of, or consist of a packaged light-emitting element (i.e., containing a bare-die light-emitting element and one or more other packaging elements such as a leadframe, lens, etc.). At least one of the electronic components may include, consist essentially of, or consist of a light-emitting diode. At least one of the electronic components may be unpackaged. At least one of the electronic components may be packaged. The substrate may include, consist essentially of, or consist of a flexible web extending from a supply roll (or supply reel) and/or extending to a take-up roll (or take-up reel). Providing the pressure-cured adhesive may include, consist essentially of, or consist of disposing the pressure-cured adhesive over at least a portion of at least one of the connection points. Providing the pressure-cured adhesive may include, consist essentially of, or consist of disposing the pressure-cured adhesive over at least a portion of at least one of the electronic components. The substrate may include thereon a plurality of conductive traces. At least one connection point may include, consist essentially of, or consist of at least a portion of a conductive trace. At least one of the conductive traces may include, consist essentially of, or consist of copper, aluminum, carbon, conductive fibers, gold, silver, one or more transparent conductive materials, and/or one or more conductive inks. substrate may include, consist essentially of, or consist of polyethylene naphthalate, polyethylene terephthalate, polycarbonate, polyethersulfone, polyester, polyimide, polyethylene, plastic, glass, metal, fabric, cloth, fiberglass, FR4, FR2, and/or paper. 
     The membrane may be pliant. When pressure is applied via the membrane, the membrane may substantially conform to the shapes of the underlying electronic components. A force multiplier may be disposed between at least one electronic component and the membrane. The force multiplier may include, consist essentially of, or consist of plastic, glass, metal, and/or paper. The force multiplier may include, consist essentially of, or consist of one or more materials that are less pliant and/or less flexible than the membrane. When pressure is applied via the membrane, the membrane may conform only partially to the shapes of the underlying electronic components. A protective layer may be disposed between at least one electronic component and the membrane. After curing the pressure-activated adhesive, the protective layer may cover or be disposed over at least one electronic component and may be adhered to at least a portion of the substrate. After curing the pressure-activated adhesive, the protective layer may be in contact with or spaced apart from at least one electronic component. 
     A shaped protective layer may be disposed between at least one electronic component and the membrane. After curing the pressure-activated adhesive, the shaped protective layer may cover or be disposed over the at least one electronic component and may be bonded (e.g., adhered) to at least a portion of the substrate. The shaped protective layer may include a curved portion that is disposed over the at least one electronic component. After curing the pressure-activated adhesive, the shaped protective layer may be in contact with or spaced apart from at least one electronic component. A second adhesive may be disposed between at least a portion of the shaped protective layer and at least a portion of the substrate. The second adhesive may be pressure-activated. A second protective layer may be disposed between at least one electronic component and the membrane. After curing the pressure-activated adhesive, the second protective layer may bond (e.g., adhere) the shaped protective layer to the substrate. The second protective layer may be disposed between the shaped protective layer and the substrate. The second protective layer may be disposed between the shaped protective layer and the membrane. The second protective layer may cover or be disposed over the at least one electronic component. The second protective layer may not cover or may not be disposed over the at least one electronic component. The second protective layer may not conformally cover the at least one electronic component. After curing the pressure-activated adhesive, the shaped protective layer may not be optically coupled to the at least one electronic component. The shaped protective layer may defines a plurality of recesses (e.g., bumps). Each recess may be disposed over one or more electronic components. The curved portion of the shaped protective layer may include, consist essentially of, or consist of an optic (e.g., be shaped as or define an optic). The optic may include, consist essentially of, or consist of a reflecting optic, a refracting optic, a total internal reflection optic, and/or a Fresnel optic. The shaped protective layer may include, consist essentially of, or consist of a plurality of curved portions. Each curved portion may be disposed over one or more electronic components. Each curved portion of the shaped protective layer may include, consist essentially of, or consist of an optic (e.g., be shaped as or define an optic). Each optic may include, consist essentially of, or consist of a reflecting optic, a refracting optic, a total internal reflection optic, and/or a Fresnel optic. The shaped protective layer may include one or more portions (e.g. straight and/or flat and/or uncurved portions) connecting the plurality of curved portions. At least two (e.g., all) of the curved portions may be discrete segments that are not connected to each other (i.e., the shaped protective layer may include, consist essentially of, or consist of a plurality of discrete, unconnected segments). 
     These and other objects, along with advantages and features of the invention, will become more apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations. Reference throughout this specification to “one example,” “an example,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one example of the present technology. Thus, the occurrences of the phrases “in one example,” “in an example,” “one embodiment,” or “an embodiment” in various places throughout this specification are not necessarily all referring to the same example. Furthermore, the particular features, structures, routines, steps, or characteristics may be combined in any suitable manner in one or more examples of the technology. As used herein, the terms “about,” “approximately,” and “substantially” mean±10%, and in some embodiments, ±5%. The term “consists essentially of” means excluding other materials that contribute to function, unless otherwise defined herein. Nonetheless, such other materials may be present, collectively or individually, in trace amounts. 
     Herein, two components such as light-emitting elements and/or optical elements being “aligned” or “associated” with each other may refer to such components being mechanically and/or optically aligned. By “mechanically aligned” is meant coaxial or situated along a parallel axis. By “optically aligned” is meant that at least some light (or other electromagnetic signal) emitted by or passing through one component passes through and/or is emitted by the other. Substrates, light sheets, components, and/or portions thereof described as “reflective” may be specularly reflective or diffusively reflective unless otherwise indicated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which: 
         FIG. 1A  is a schematic illustration of a semiconductor die bonded to stud bumps on a substrate via a pressure-activated adhesive; 
         FIG. 1B  is a schematic illustration of a semiconductor die bonded without stud bumps on a substrate via a pressure-activated adhesive; 
         FIG. 1C  is a schematic illustration of a thermode system for curing a pressure-activated adhesive; 
         FIGS. 2A-2C  are schematic illustrations of curing systems in accordance with various embodiments of the invention; 
         FIG. 3  is a flow chart of a process for curing pressure-activated adhesive in accordance with various embodiments of the invention; 
         FIGS. 4A-4E  are schematic illustrations of various steps utilized to cure pressure-activated adhesives in accordance with various embodiments of the invention; 
         FIGS. 5A and 5B  are schematic illustrations of curing systems in accordance with various embodiments of the invention; 
         FIG. 6  is a schematic illustration of a curing system in accordance with various embodiments of the invention; 
         FIG. 7A  is a schematic plan view of a heater in accordance with various embodiments of the invention; 
         FIG. 7B  is a schematic plan view of an exemplary layout of electronic devices to be cured in accordance with various embodiments of the invention; 
         FIG. 7C  is a schematic plan view of the heater of  FIG. 7A  with selected heating elements activated to cure the electronic devices of  FIG. 7B ; 
         FIG. 8  is a schematic illustration of a curing system in accordance with various embodiments of the invention; 
         FIG. 9A  is a schematic cross-section of a substrate prior to curing in accordance with various embodiments of the invention; 
         FIG. 9B  is a schematic cross-section of the substrate of  FIG. 9A  after curing; 
         FIGS. 9C-9E  are schematic cross-sections of substrates after curing in accordance with various embodiments of the invention; 
         FIG. 9F  is a schematic cross-section of an electronic device incorporating a shaped film in accordance with various embodiments of the invention; 
         FIG. 9G  is a schematic cross-section of a shaped film in accordance with various embodiments of the invention; 
         FIG. 9H  is a schematic cross-section of an electronic device incorporating a shaped film in accordance with various embodiments of the invention; 
         FIG. 10A  is a schematic cross-section of a curing system incorporating a force modifier in accordance with various embodiments of the invention; and 
         FIG. 10B  is a schematic cross-section of a curing system incorporating a force modifier membrane in accordance with various embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2A  is a schematic showing an adhesive curing apparatus in accordance with embodiments of the present invention. In curing processes in accordance with embodiments of the invention, the components or assembly or circuit board to be cured are positioned between a membrane  210  and a base  230 . Herein, the term “circuit board” is utilized to represent any platform or substrate to which devices or components are meant to be attached. A circuit board may, but does not necessarily, have a network of traces or other electrical connections that interconnect such devices into one or more electrical circuits. In various embodiments of the present invention, the basic process may proceed as follows. An adhesive  205  is dispensed, components  280  are placed, flexible membrane  210  is placed over the assembly to be cured, pressure is applied to the components  280  via membrane  210 , and heat is applied to cure the adhesive. The adhesive  205  may include or consist essentially of, e.g., an ACA or another conductive adhesive (e.g., an isotropically conductive adhesive). 
       FIG. 2A  shows a component  280  having electrical contacts  285 , as well as adhesive  205  disposed between the component  280  and conductive traces  160  that are disposed on substrate  120 . The assembly or item to be cured, here including components  280 , adhesive  205 , conductive traces  160 , and substrate  120 , is placed between membrane  210  and base  230 . In various embodiments of the present invention, during the curing process, pressure and heat are applied to adhesive  205 . Pressure is applied to adhesive  205  by membrane  210  applying pressure to components  280 , as will be discussed herein, while heat may be applied using a variety of means, as will be discussed herein, and other elements of the apparatus or assembly may be heated as well during this process. In various embodiments of the present invention, pressure and heat may be applied simultaneously, while in other embodiments the timings of the application of heat and pressure may be different. 
     In various embodiments of the present invention, pressure may be applied to the components by various means, e.g., application of a fluid or gas pressure to the exterior side of membrane  210  (i.e., the side of membrane  210  that is opposite the side adjacent to component  280 ), which is identified as region  211  in  FIG. 2A . In various embodiments, pressure may be applied to the components by evacuating or partially evacuating a region  212  between membrane  210  and the components, for example by pumping the air (or gas or fluid) out of region  212  or partially pumping the air (or gas or fluid) out of region  212 . In various embodiments, this forms a reduced (i.e., negative) pressure in region  212  compared to region  211 , thereby applying pressure to the components via membrane  210 . In various embodiments, pressure may be applied to the exterior side of membrane  210  (region  211 ) and region  212  may be evacuated or partially evacuated. In various embodiments, pressure may be applied to the exterior side of membrane  210  (region  211 ) without evacuating or partially evacuating region  212 . In such cases, in various embodiments, pressure applied to region  211  may force all or substantially all of the air or fluid from region  212 . However, these methods of applying pressure are not a limitation of the present invention, and in other embodiments pressure may be applied in other ways, for example by pulling or stretching the membrane against the components. In various embodiments of the present invention, the pressure that is applied to components  280  is transferred or substantially transferred to adhesive  205 , and not substantially dissipated in other portions of the assembly and/or apparatus. In various embodiments of the present invention, base  230  is rigid or substantially rigid, such that pressure applied to components  280  is transferred or substantially transferred to adhesive  205  and is not dissipated or transferred to other portions of the apparatus. In various embodiments, base  230  is not deformed or substantially deformed during the curing process. 
       FIG. 2B  is a schematic showing an adhesive curing apparatus in accordance with embodiments of the present invention. The apparatus of  FIG. 2B  is similar to that described in reference to  FIG. 2A ; however, the apparatus of  FIG. 2B  incorporates one or more heaters  290  for applying heat to adhesive  205 . In various embodiments of the present invention, heater(s)  290  may be incorporated in or on base  230  or may be disposed on base  230 . In various embodiments, base  230  or heater  290  or other elements of the apparatus may include a system for improving thermal contact between the circuit board and the heater, for example a clamping mechanism to hold the circuit board in contact with the heater and/or a thermal paste or other thermal conductor to facilitate thermal conductivity between the heater  290  and the circuit board. In various embodiments, the circuit board may be held in contact with the heater using a vacuum plate, for example including one or more vacuum holes or ports or a porous vacuum plate or chuck. 
     Various embodiments of the invention beneficially use the membrane  210  to apply pressure to components  280  during the adhesive curing process. By evacuating the air under membrane  210  and/or increasing the gas or fluid pressure above membrane  210 , membrane  210  is pressed against components  280 , applying force to each component. The pressurized membrane replaces the thermodes of the conventional approach discussed in reference to  FIG. 1C . The membrane-pressure cure approach of embodiments of the present invention has a number of significant advantages over conventional approaches. First, pressure is applied uniformly to all components on the circuit board, independent of the size of the circuit board and number of components. Second, the pressure that is applied to each component is determined by the gas, fluid or air pressure above the membrane and/or the vacuum or pressure level under membrane  210  (in region  212 ). 
     In various embodiments, this may simplify setting the pressure for curing, as the pressure experienced by all of the components beneath the membrane is determined by the gas, fluid, or air pressure above the membrane and/or the vacuum or pressure level under the membrane. In contrast, in traditional approaches each thermode typically must be individually calibrated. In conventional systems, one thermode is used for each component; thus, embodiments of the present invention may permit a large reduction in the number of components of the curing system as well as a simplification of the curing equipment, for example elimination of all of the individual thermodes as well as the control and monitoring wiring (electrical and pneumatic) and equipment that is connected to each thermode. Finally, in various embodiments, the present invention may enable an overall reduction in the number of calibrations and settings required for a cure process. 
     Third, the flexible membrane may easily conform to a wide range of components having different sizes, heights, and/or positions. This is particularly important because it permits one system to be used for a wide range of circuit boards without the need to reconfigure a thermode field to accommodate different component heights, different component sizes, and/or different component positions and/or spacings. For example, in conventional thermode systems, each time there is any change in a component position, for example a new layout or a different circuit board, the thermode configuration must be changed, which for large arrays of thermodes, for example arrays numbering in the range of 20-100, can take significant time. In various embodiments of the present invention, different layouts or designs may be cured without any reconfiguration of the curing apparatus. 
     Fourth, membrane  210  may have a relatively high level of flexibility, permitting it to conform to small components and/or components having relatively small inter-component spacing, eliminating the cost and lead time to manufacture a custom thermode, such as a custom pin thermode, and permitting embodiments of the present invention to work with a variety of circuit boards, component heights, sizes, thicknesses, and/or spacings without the need to reconfigure the system between different samples. 
     Fifth, by curing all the components at the same time, the curing system of embodiments of the present invention may eliminate pre-curing (i.e., unintentional curing or partial curing) of the adhesive before curing is desired, and embodiments of the invention may minimize the required processing time and increase throughput because all components are cured simultaneously (in comparison with conventional thermode curing in which multiple sequential cure steps may be required to cure a dense field of components). These advantages result in a significant reduction in cost as well as a significant reduction in set-up time between different designs. 
       FIG. 2C  depicts a more detailed exemplary apparatus  200  for use in various embodiments of the present invention; however, other apparatuses may be utilized within the scope of the invention. As also shown in  FIG. 2A , substrate  120  with conductive traces  160  is placed on base  230 . In the apparatus of  FIG. 2C , heater  290  is incorporated into base  230 ; however, this is not a limitation of the present invention, and in other embodiments other methods and/or systems may be used to provide heat. In various embodiments, membrane  210  may be optionally sealed to base  230  by a seal  220 . In various embodiments, air may be evacuated from the area under membrane  210  using a vacuum source  245  through a valve  243  and a vacuum hose  240 . In various embodiments, pressure may be applied to the interior of chamber  250  (thereby applying pressure to membrane  210 , which imparts pressure to components  280 ) by a pressure source  270  through an optional pressure regulator  272 , a valve  274 , and a pressure hose  275 . The temperature of heater  290  may be monitored by one or more temperature sensors  292  that may be connected to a heater controller  298  by a temperature sensor connection  294 . Power to heater  290  may be applied from heater controller  298  by a heater connection  296 . While  FIG. 2C  shows one temperature sensor  292 , this is not a limitation of the present invention, and in other embodiments multiple temperature sensors  292  may be utilized. While  FIG. 2C  shows temperature sensor  292  mounted between heater  290  and substrate  120 , this s not a limitation of the present invention, and in other embodiments the temperature may be measured in different locations, for example on one or more conductive traces  160 , under component  280 , and/or within ACA  205 . An optional over-pressure release system  255  (e.g., one or more valves configured to open at a particular threshold pressure inside chamber  250 ) may be incorporated to prevent accidental over-pressurization of chamber  250  and concomitant damage to the apparatus and/or to the components being cured. 
       FIG. 3  depicts a flowchart of an exemplary process  300  in accordance with various embodiments of the invention. Process  300  is shown having eight steps; however, this is not a limitation of the present invention, and in other embodiments the invention has more or fewer steps and/or the steps may be performed in different order. In step  310 , a circuit board is provided. In various embodiments, the circuit board may be rigid or flexible and in various embodiments may include or consist essentially of substrate  120  with conductive traces  160 , as shown in  FIG. 2A . In step  320 , an adhesive is provided or dispensed over the substrate and/or the components to be attached to the substrate. In step  330 , the components, chips, or devices are placed on the substrate. In step  340 , a membrane is provided. In step  350 , the membrane is positioned over the substrate and components. In step  360 , air is evacuated from between the membrane and substrate. In step  370 , pressure, for example gas or fluid pressure, is applied to the membrane. In step  380 , which may take place substantially concurrently (or overlapping in time) with steps  360  and/or  370 , the adhesive is cured. In various embodiments of the present invention, pressure is applied to the adhesive in steps  360  and  370 . In various embodiments of the present invention, either step  360  may be performed without step  370 , or step  370  may be performed without step  360 , or pressure may be applied by other means. In various embodiments heat may be applied in steps  360  and/or  370 . 
       FIGS. 4A-4E  depict one embodiment of process  300  of  FIG. 3 . In the depicted embodiment, a circuit board  165  is provided according to step  310  of process  300  as shown in  FIG. 4A . In various embodiments of the present invention, circuit board  165  includes or consists essentially of a base or substrate  120  over and/or in which are disposed multiple conductive elements  160 . In various embodiments of the present invention, circuit board  165  is flexible, while in other embodiments circuit board  165  may be rigid or semi-rigid. The rigidity of circuit board  165  is not a limitation of the present invention. In various embodiments of the present invention, substrate  120  may include, consist essentially of, or consist of one or more of the following: fiberglass, FR4, FR2, acrylic, cloth, polyester, polyimide, polyethylene, polyethersulfone, polyethylene napthalate (PEN), polyetherimide (PEI), polyethylene terephthalate, aluminum, metal, metal core printed circuit board, (MCPCB), fabric, paper, or glass. In various embodiments of the present invention, conductive elements  160  may include, consist essentially of, or consist of one or more of the following: copper, aluminum, carbon, conductive fibers, gold, silver, transparent conductive materials (e.g., transparent conductive oxides such as indium tin oxide), conductive nanocomposites, or conductive ink. The materials of substrate  120  and conductive elements  160  are not limitations of the present invention. In various embodiments of the present invention, as shown in  FIG. 4A , conductive elements  160  may be separated by a gap  410 . 
     In step  320  of process  300 , the adhesive is provided and formed or dispensed in the appropriate locations on the circuit board.  FIG. 4B  shows various examples of how the adhesive may be deposited; however, these are not limitations of the present invention, and in other embodiments adhesive may be dispensed in other ways and/or patterns. In various embodiments of the present invention, a single volume of adhesive may be dispensed over a portion of gap  410  and a portion of conductive traces  160  on either side of gap  410 , for example as shown for adhesive  205 . In various embodiments of the present invention, two or more separate volumes of adhesive may be dispensed for each component to be bonded to circuit board  165 . In various embodiments of the present invention, a volume of adhesive may be dispensed over a portion of conductive trace  160 , next to gap  410 , for example as shown for adhesive  205 ″ in  FIG. 4B . In various embodiments of the present invention, a volume of adhesive may be dispensed over a portion of conductive trace  160  and a portion of gap  410 , for example as shown for adhesive  205 ′ in  FIG. 4B . These examples are not meant to be limiting, and in other embodiments other adhesive-dispense geometries may be utilized, for example one or more volumes may be dispensed on substrate  120  within gap  410 , or two or more volumes may be dispensed perpendicular to the plane of the drawing of  FIG. 4B , or any other dispense geometry. 
     In various embodiments, the adhesive may be provided by dispensing, by jetting, by pressurized syringe dispense, printing, screen printing, ink jet printing, or the like. In some embodiments, the adhesive may be formed manually or in an automated or semi-automated fashion. The method of adhesive dispense is not a limitation of the present invention. In various embodiments of the present invention, adhesive  205  may be applied or dispensed on to the entirety of or only one or more portions of each of the components. For example, adhesive  205  may be applied to the entirety of or only a portion of one or more of the contacts of the component rather than or in addition to being dispensed on the circuit board. In various embodiments of the present invention, adhesive  205  may be applied to or dispensed on the entirety of or only one or more portions of each of the component(s) and/or on the circuit board. 
     In various embodiments, adhesive  205  includes, consists essentially of, or consists of an ACA. In various embodiments, the adhesive or ACA may include, consist essentially of, or consist of a liquid, a gel, a paste, or a film (e.g., anisotropic conductive film, ACF); the form of the adhesive or ACA is not a limitation of the present invention. In various embodiments, adhesive  205  may include, consist essentially of, or consist of a conductive adhesive (e.g., an isotropically conductive adhesive). ACAs may be utilized with or without stud bumps, and embodiments of the present invention are not limited by the particular mode of operation of the ACA. Furthermore, various embodiments may utilize one or more other electrically conductive adhesives, e.g., isotropically conductive adhesives, non-conductive adhesives, in addition to or instead of one or more ACAs. In various embodiments, the adhesive may be pre-dispensed on component  280 , for example over all, substantially all or a portion of the bottom contact-containing face of component  280  (that is the face of component  280  that includes contacts  285 ), for example as described in U.S. patent application Ser. No. 13/784,417, filed on Mar. 4, 2013, U.S. patent application Ser. No. 13/784,419, filed on Mar. 4, 2013, and/or U.S. patent application Ser. No. 13/949,546, filed on Jul. 24, 2013, the entire disclosure of each of which is incorporated by reference herein, which, in various embodiments, eliminates the need for step  320 . 
     In various embodiments of the present invention, adhesive  205  may be cured by application of one or more of heat, pressure, electromagnetic waves, microwaves, magnetic field, or optical radiation (for example UV radiation). 
     In step  330  of process  300 , component  280  is positioned over substrate  120 , conductive traces  160 , and adhesive  205  as shown in  FIG. 4C . In various embodiments of the present invention, component  280  is a bare (i.e., unpackaged) die, for example a bare semiconductor die, e.g., an integrated circuit, a transistor, a resistor, a capacitor, a diode, a light-emitting diode (LED), a laser, a solar cell, a light detector, or any other bare semiconductor die, also known as a semiconductor chip. In various embodiments of the present invention, component  280  is a packaged device, for example a packaged semiconductor device, e.g., a packaged integrated circuit, a packaged transistor, a packaged diode, a packaged LED, a packaged laser, a packaged solar cell, a packaged light detector, a packaged resistor, a packaged capacitor, a packaged inductor, or any other packaged device. In various embodiments of the present invention, component  280  is a packaged surface mount device (SMD); however, the specific package type is not a limitation of the present invention. In various embodiments, packaged components may utilize one or more different package types, for example molded packages, leaded packages, leadless packages, chip scale packages (CSP), plastic leaded chip carrier (PLCC), or the like. The specific type of bare die or packaged device is not a limitation of the present invention. 
     As shown in  FIG. 4C , component  280  may have one or more contacts  285 , and in various embodiments of the present invention, at least a portion of contact  285  is positioned over at least a portion of conductive trace  160 , such that after curing, an electrically conducting pathway is formed from conductive trace  160  to contact  285 , for example through adhesive  205 . In various embodiments of the present invention, one or more stud bumps, as described in reference to  FIG. 1A , may also be incorporated into the structure between the trace  160  and the contact  285  (e.g., in contact with or as part of the trace  160  and/or in contact with or as part of the contact  285 ). 
     Components  280  may be placed on circuit board  165  by a number of means, for example using die bonders, pick-and-place tools, manual placement, semi-automated placement, fully automated placement, or the like. The method of component placement is not a limitation of the present invention. 
     While  FIG. 4C  shows two components  280 , this figure is meant to be exemplary and the number of components is not a limitation of the present invention. In various embodiments, this technique may be applied to tens, hundreds, thousands, or more components serially or substantially simultaneously. While  FIG. 4C  shows two of the same components  280 , this is not a limitation of the present invention, and in other embodiments different components, for example having different areas, heights, pad configurations, or the like, may be processed serially or simultaneously. The quantity, type, and spacing of components are not limitations of the present invention. Indeed, as described herein, one advantage of embodiments of the present invention is the ability to substantially simultaneously treat two or more different types and/or sizes of components. 
     In step  340 , a membrane is provided. In step  350 , membrane  210  is placed over the circuit board and components, for example as shown in  FIG. 4D . One purpose of membrane  210  is to distribute the gas or fluid pressure that is applied to membrane  210  to components  280  in a uniform or substantially uniform fashion. In various embodiments, the pressure is applied to components  280  substantially independently of component height, shape, and/or spacing. In various embodiments of the present invention, membrane  210  may cover all components  280 ; however, this is not a limitation of the present invention, and in other embodiments membrane  210  may only cover one or some of components  280  on circuit board  165 . For example, in various embodiments of the present invention, the components on a circuit board may be cured in more than one step, that is some of the components may be cured, and then a second (or more) group may be subsequently cured. 
     In various embodiments of the present invention, membrane  210  may include, consist essentially of, or consist of one or more of the following materials: nylon, polyethylene, polyester, or silicone. In various embodiments of the present invention, membrane  210  may be stretchable, for example able to stretch up to at least about 50% of its original length, up to at least about 100% of its original length, up to at least about 250% of its original length, up to at least about 500% of its original length, or more. Examples of suitable membranes include Stretchlon 200 and Stretchlon 800 manufactured by Airtech International. In various embodiments of the present invention, membrane  210  may be used only once, for example for only one cure process; however, this is not a limitation of the present invention, and in other embodiments membrane  210  may be used multiple times. In various embodiments of the present invention, membrane  210  may be clear or transparent; however, this is not a limitation of the present invention, and in other embodiments membrane  210  may be translucent or opaque. In various embodiments of the present invention, membrane  210  may include, consist essentially of, or consist of one material or multiple materials; for example, membrane  210  may include, consist essentially of, or consist of a film having layers of multiple different materials, in which each layer or material may have different mechanical and/or thermal properties. In various embodiments of the present invention, different materials of construction of membrane  210  may be utilized to meet different process and manufacturing needs, for example process temperatures, process duration, flexibility, cost, and/or membrane longevity. In some embodiments, a flexible membrane  210  is configurable to a radius of curvature of about 1 m or less, or about 0.5 m or less, or even about 0.1 m or less. In some embodiments, flexible membrane  210  has a Young&#39;s Modulus less than about 100 N/m 2 , less than about 1 N/m 2 , less than about 0.1 N/m 2 , or even less than about 0.05 N/m 2 . In some embodiments, a flexible membrane  210  has a Shore A hardness value less than about 100; a Shore D hardness less than about 100; and/or a Rockwell hardness less than about 150. 
     In various embodiments of the present invention, circuit board  165  may be positioned over or on a base, for example base  230  as shown in  FIG. 4D . While circuit board  165  is shown being positioned on base  230  in step  340 , this is not a limitation of the present invention, and in other embodiments circuit board  165  may be positioned on base  230  during a different stage of the process, or base  230  may not be utilized. In various embodiments, base  230  may incorporate a means of providing heat to circuit board  165 , and in particular to providing heat to adhesive  205  for the curing process.  FIG. 4D  shows base  230  incorporating heater  290 , although in other embodiments base  230  may incorporate more than one heater, or one or more heaters may be incorporated in other portions of the apparatus, or a heater may not be part of the apparatus. For example, in various embodiments of the present invention the structure of  FIG. 4D , but without heater  290 , may be placed in an autoclave, an oven, or a similar apparatus that provides a means for heating of (and even, in various embodiments, application of pressure to) membrane  210 . In various embodiments of the present invention, curing may be performed using other energy sources (e.g., UV lamps or other UV light sources), as described herein, and in such cases appropriate equipment may be utilized for such cure processes. 
     In various embodiments of the present invention, membrane  210  may be sealed to base  230 , for example to permit evacuation of air between circuit board  165  and membrane  210  in step  360 , as described herein.  FIG. 4E  shows seal  220  providing a seal between membrane  210  and base  230 ; however, this is not a limitation of the present invention, and in other embodiments seal  220  may be between membrane  210  and other elements of the system, for example substrate  120 , one or more conductive traces  160 , or the like. In various embodiments of the present invention, seal  220  may not be utilized. In various embodiments of the present invention, seal  220  may be a one-time seal, for example an adhesive, glue, tape, or sealant tape, for example Gray or Yellow sealant tape from Fiberglast Development Corporation. In various embodiments of the present invention, seal  220  may be reusable. Examples of reusable seals include o-rings, gaskets, or the like. 
     In step  360 , the air may be evacuated from between membrane  210  and the circuit board, for example the air or fluid may be evacuated from region  212  of  FIG. 2A .  FIG. 4E  shows a port  241  attached to membrane  210 , to which is attached a hose or tube  240  coupling the region between membrane  210  and circuit board  165  to vacuum source  245 . A valve  243  may be optionally positioned between vacuum source  245  and port  241  to permit control of the application of vacuum from vacuum source  245  to the region under membrane  210 . In various embodiments of the present invention, membrane  210  may be sealed to a base, for example base  230  as shown in  FIG. 4E ; however, this is not a limitation of the present invention, and in other embodiments seal  220  may not be present or membrane  220  may seal itself to base  230  or another portion of the apparatus by the application of vacuum. In various embodiments of the present invention, vacuum source  245  may include one or more of the following: vacuum pump, vacuum generator, house vacuum source, or the like. The means of generating a vacuum or negative pressure is not a limitation of the present invention. While the apparatus of  FIG. 4E  shows port  241  attached to or formed within membrane  210 , this is not a limitation of the present invention, and in other embodiments the air or fluid may be evacuated or partially evacuated through other parts of the apparatus, for example through base  230 . 
     In various embodiments of the present invention, the air or fluid may be evacuated from under membrane  210 , and vacuum source  245  may be removed (e.g., valve  243  and/or port  241  may be closed) prior to curing the adhesive. In various embodiments of the present invention, the atmosphere under membrane  210  may be continuously evacuated by vacuum source  245  during the curing stage. In various embodiments of the present invention, a separate vacuum source may be part of a pressure chamber, for example a pressure chamber (as described herein) used to apply pressure to the exterior of membrane  210 . 
     In various embodiments of the present invention, heater  290  may be on or part of base  230  and may be a thin-film heater, for example including one or more resistive heater traces on a heater substrate. In various embodiments, the heater substrate may include or consist essentially of silicone, polyimide (e.g., Kapton), or the like. Other means of heating may also be utilized, for example induction heating, lamp heating, infrared (IR) lamp heating, radio frequency (RF) induction heating, thermoelectric heating, rapid thermal heating (e.g., using induction or radiation), microwave heating, fluid heating, or the like. In various embodiments of the present invention, a fluid may be used to apply pressure (i.e., positive pressure) to the exterior of membrane  210 . In various embodiments, the fluid may be heated, resulting in heating of membrane  210  and adhesive  205 . In various embodiments of the present invention, one or more heaters may be incorporated within or as part of membrane  210 . For example, one or more resistive heater traces may be incorporated on or within membrane  210 . 
     In various embodiments of the present invention, adhesive  205  is an ACA and the ACA cure process first applies pressure and then cures the adhesive to lock or freeze the conductive particles in place, such that after removal of the pressure, there is little or no movement of the conductive particles within the adhesive matrix of the ACA. This maintains an electrically conducting pathway between conductive trace  160  through the conductive particle(s) to contact  285 . In such embodiments, it may be preferable to first apply the pressure and then to cure the adhesive, for example by application of heat, UV radiation, or the like; however, this is not a limitation of the present invention, and in other embodiments other temperature-pressure-time cure profiles may be used. For example, in various embodiments it may be advantageous to heat the adhesive to a temperature below the cure point prior to or while applying pressure, for example to achieve a reduction in viscosity of the adhesive, before applying pressure and curing the adhesive. In various embodiments, the temperature and/or pressure may be constant or substantially constant during the cure process, while in other embodiments the temperature and/or pressure may change during the cure process. For example, in various embodiments of the present invention, the adhesive may be cured using the following process conditions: a force in the range of about 0.5 N to about 10 N, a cure time in the range of about 5 seconds to about 360 seconds, and a cure temperature in the range of about 60° C. to about 350° C. In various embodiments, the adhesive may be Delo  265  and the cure process includes a force of about 1.3 N to about 10 N, a time in the range of about 5 seconds to about 30 seconds, and a temperature in the range of about 150° C. to about 210° C. 
     In step  370 , pressure is applied to the membrane. For example, in various embodiments pressure may be applied over membrane  210 , which forces membrane  210  onto components  280 , which applies the pressure to the adhesive. In various embodiments of the present invention, pressure may be applied by placing the system (or parts of the system) of  FIG. 4E  into a pressure chamber, for example pressure chamber  250  as shown in  FIG. 2B . The pressure within chamber  250  is controlled by pressure source  270  which is applied to pressure chamber  250  through pressure regulator  272 , valve  274 , and tube  275 . In various embodiments, pressure chamber  250  may include a pressure relief valve  255 , to prevent over-pressure of chamber  250 . 
     In various embodiments of the present invention, the pressure in the chamber may be increased by applying a pressurized fluid from pressure source  270  to the interior of chamber  250 . In various embodiments of the present invention, the pressurized fluid may be a gas, for example nitrogen, argon, air, or the like. In various embodiments of the present invention, the pressurized fluid may be a liquid, for example water, ethylene glycol, silicone oil, or the like. In some embodiments of the present invention, the pressurized fluid may also be heated to aid in heating or provide the heat for curing the adhesive. 
     In various embodiments of the present invention, pressure may be applied solely by evacuating or partially evacuating the air or fluid under membrane  210 . In various embodiments of the present invention, evacuating the air under membrane  210  may result in a pressure substantially equal to atmospheric pressure, for example in the range of about 14 to about 15 pounds per square inch. In various embodiments of the present invention, pressure may be applied by a combination of by evacuating or partially evacuating the air or fluid under membrane  210  and application of pressure over membrane  210 . 
     In step  380 , the adhesive is cured. In various embodiments, the adhesive is cured by application of heat, as described herein; however, this is not a limitation of the present invention, and in other embodiments curing may be accomplished by other means, for example exposure to other forms of energy, moisture, radiation (e.g., UV radiation), or the like. In various embodiments, curing may be accomplished using more than one means, for example heat and UV radiation or moisture and heat. In various embodiments, heat may be introduced by various means, for example electrical heaters, infrared radiation, microwave radiation, induction heating, thermoelectric heating, or the like. In various embodiments, the cure profile (time and temperature) is dependent on the characteristics of the adhesive. In various embodiments, the temperature may be in the range of about 50° C. to about 350° C. In various embodiments, the cure temperature may be reduced by increasing the cure time. The cure temperature and time are not limitations of the present invention. 
     In various embodiments of the present invention, heat is applied before the pressure is applied, while in other embodiments heat and pressure are applied simultaneously or substantially simultaneously, or heat may be applied after pressure is applied. In various embodiments of the present invention, the temperature of the adhesive ramps up from its starting value over a period of time, and the heater may be turned on at the same time or substantially the same time as the pressure is applied, such that the desired pressure is reached before the final cure temperature is reached. 
     After the adhesive is cured, the circuit board with associated components and cured adhesive may be removed from the pressure curing system. 
     In various embodiments, the time for one cure cycle may be in the range of about 5 seconds to over 2 hours. In various embodiments, the cure cycle time is dependent on the rate of heating and cooling. In systems having relatively large thermal mass, such as an autoclave, the cycle time may be about two hours or more, or about one hour or less, or about 30 minutes or less. For systems having relatively lower thermal mass, the cycle time may be less than about 10 minutes, or less than about 1 minutes, or less than about 30 seconds, or less than about 10 seconds. In various embodiments, the cure system may incorporate thermal insulation and/or active or passive cooling to aid in quickly attaining the desired process conditions and/or to reduce cycle time. For example, in various embodiments, cooling, for example air, water, fluid, thermoelectric, or other means of cooling, may be utilized to reduce the cooling time of the system. In various embodiments, insulation may be utilized to reduce the heating time of the system, for example to reduce heating of portions of the system outside of the cure region (i.e., the region containing the adhesive being cured).  FIG. 2C  shows an apparatus that may be used in accordance with embodiments of the present invention; however, this is not a limitation of the present invention, and in other embodiments other apparatuses may be used. For example, in one embodiment of the present invention, the process may take place in an autoclave. In such embodiments, the pressure within the chamber is increased and the entire chamber is heated, for example using heaters within the chamber, but not necessarily under the circuit board and associated components. In various embodiments of the present invention, the circuit board and associated components may be heated from above, or from both above and below, to cure the adhesive. 
     It will be understood by those skilled in the art that the cure conditions involve a combination of factors, e.g., the time-temperature and time-pressure profile, and that these may be varied to find suitable conditions for curing without undue experimentation. For example, in various embodiments of the present invention the cure time may be reduced by increasing the cure temperature, while in other embodiments the cure temperature may be reduced by increasing the cure time. In various embodiments of the present invention, the applied pressure profile may also affect the temperature profile. 
       FIG. 5A  shows an apparatus used in accordance with embodiments of the present invention. The apparatus of  FIG. 5A  is similar to that of  FIG. 2C ; however, in  FIG. 5A  pressure chamber  250  and heater  290  are replaced by a chamber  510  that provides both pressure and heat, for example an autoclave-type chamber (the means for applying and controlling the pressure and heat in chamber  510  are not shown in  FIG. 5A , but such systems are commercially available and such means are well understood). In various embodiments, chamber  510  may be relatively large and multiple circuit boards or items may be cured simultaneously. For example, many circuit boards with membrane  210  on base  230  may be placed in chamber  510  for simultaneous curing, for example on racks or shelves within chamber  510 . Multiple such circuit boards may be disposed beneath a single membrane  210  and/or on a single base  230 , or each circuit board may have its own dedicated membrane  210  and/or base  230 . 
     In various embodiments, additional elements may be added to the system and process, for example to increase throughput or control of the process. For example, in various embodiments, one or more pressure sensors may be positioned within chamber  250  or chamber  510  to measure and/or control the pressure. In various embodiments, the pressure may be changed in the chamber in a step-wise or relatively step-wise fashion, while in other embodiments the pressure may be more gradually changed, or continuously or substantially continuously changed over a period of time. As discussed herein, one or more temperature monitors may be placed within chamber  250  or chamber  510 , for example in the chamber, on one or more conductive traces  160 , for example near adhesive  205  or in other locations, to measure and/or control the temperature during the process. In various embodiments, the temperature may be changed in the chamber in a step-wise or relatively step-wise fashion, while in other embodiments the temperature may be more gradually, continuously, or substantially continuously increased over a period of time. In various embodiments, a means for cooling the sample and/or chamber after curing may be incorporated, for example to increase throughput. For example, in various embodiments, cooling may be accomplished using gas or air cooling, water cooling, thermo-electric cooling, liquid nitrogen cooling, or the like. In various embodiments, the heating, pressure, and cooling characteristics as a function of time may be optimized for desired processing conditions and high throughput. In various embodiments, the entire cure process may take place in less than 2 minutes, or less than 1 minute, or less than 30 seconds, or less than 15 seconds. 
     In various embodiments, circuit boards may be cured using the process of the present invention in a batch process. For example a circuit board may be loaded into the system, for example as shown in  FIG. 2C  or  FIG. 5A , and the adhesive cured and the circuit board removed. However, in various embodiments the circuit board may include or consist essentially of a web supplied from a supply roll for roll-to-roll processing.  FIG. 5B  shows an exemplary embodiment of a roll-to-roll system for package and/or die attach using the pressure cure process of embodiments of the present invention.  FIG. 5B  shows a system  501  including a web  580  that is supplied from a supply roll  520  and taken up on a take-up roll  530 , as well as various process stations, including an adhesive dispense station  540 , a component placement station  550 , a pressure cure station  560 , and an optional test station  570  (for, e.g., electronically testing one or more of the bonded components after the adhesive is cured). 
     The pressure cure station  560  may include or consist essentially of, e.g., any of the components described herein in conjunction with pressure-application and curing. The adhesive dispense station  540  may include a reservoir for containing the adhesive and from which the adhesive may be dispensed. The adhesive dispense station  540  may also include one or more mechanisms for dispensing the adhesive, e.g., one or more jets, one or more syringes, one or more print heads (e.g., ink jet print heads), etc. The component placement station  550  may include or consist essentially of one or more mechanisms for placing the components over their respective connection points, e.g., one or more die bonders, one or more pick-and-place tools, etc. The test station  570  may include or consist essentially of, for example, one or more testing-station components as detailed in U.S. patent application Ser. No. 14/949,089, filed on Nov. 23, 2015, the entire disclosure of which is incorporated by reference herein. For example, the test station  570  may include a power source for applying power (e.g., current and/or voltage) to one or more of the bonded components, one or more electrical probes for electrically contacting the components (e.g., a probe card), as well as one or more analyzers for analyzing electrical and/or optical output of the components, e.g., a spectrometer, an integrating sphere, a voltmeter, an ammeter, a source measure unit (i.e., a unit capable of sourcing (providing power to) and measuring (for example measuring a voltage or current of) one or more components at the same time), and/or a still and/or video camera. 
     In various embodiments, membrane  210  may include or incorporate one or more heating elements that may be used to provide heat to cure adhesive  205 .  FIG. 6  shows a schematic of an embodiment of the present invention in which a membrane  610  incorporates one or more heating elements. In this embodiment, one or more heating elements within or part of membrane  610  provide the heat for curing, while pressure applied via membrane  610  provides the pressure for curing. In various embodiments, membrane  610  may include, consist essentially of, or consist of silicone, silicone rubber, polyester, Kapton, polyimide, or the like. The heating elements incorporated into the membrane  610  may include, consist essentially of, or consist of, for example, wires or other resistive heating elements. 
     In various embodiments of the present invention, heater  290  may include or consist essentially of an array of addressable heating elements, such that heat may be applied selectively to various regions of the circuit board or assembly containing material to be cured.  FIG. 7A  shows a schematic top view of one embodiment of an addressable heater featuring multiple heating elements  760  on base  230 . While  FIG. 7A  shows each individual heating element  760  as having a square shape, this is not a limitation of the present invention, and in other embodiments heating elements  760  may have different shapes, for example triangular, circular, hexagonal, rectangular, or any other shape or any arbitrary shape. While  FIG. 7A  shows heating elements  760  arranged in a regular periodic array, this is not a limitation of the present invention, and in other embodiments heating elements  760  may be arranged in different patterns.  FIG. 7B  shows a schematic of a circuit board  710  having four components  720 ,  730 ,  740 , and  750  that are to be cured.  FIG. 7C  shows a schematic of the heater of  FIG. 7A , with some of heating elements  760  activated for applying heat in the regions of components  720 ,  730 ,  740 , and  750 , while other heating elements  760  are not activated (i.e., not actively applying heat). In  FIG. 7C  activated heating elements  760  are indicated by a grey color. In various embodiments, the area of heating elements  760  that are activated may be larger than the corresponding component, for example as shown for components  730  and  750 , or may be smaller than the component, for example as shown for component  740 , or may be substantially the same size, as shown for component  720 . In various embodiments, heating elements  760  may be programmed to be activated or deactivated based on a drawing, picture, CAD file, or file or other representation of the position of the components to be cured. Such representations may be stored as digital information in a computer memory incorporated within or in communication with a computer-based control system that controls the activation of the heating elements  760 . In various embodiments, circuit board  710  may be imaged or scanned and the appropriate heating elements determined from the image or scan. In various embodiments, a heating element  760  may be off or on, while in other embodiments the temperature for different heating elements  760  may be different (and/or each heating element  760  may be programmed to apply heat at any one of multiple different levels), for example to provide different amounts of heat to different components, or to provide specific lateral or vertical thermal profiles. In various embodiments, all heating elements  760  may be activated or deactivated simultaneously; however, this is not a limitation of the present invention, and in other embodiments various heating elements may be activated at different times, for example to provide different amounts of heat to different components, or to provide specific lateral or vertical thermal profiles. In various embodiments of the present invention, various components may have different thermal conductivities, different thicknesses, different contact areas or have other differences that may result in different heating rates, and in some embodiments curing may be accomplished using one temperature/time profile, for example as described with respect to  FIG. 3 , while in other embodiments it may be advantageous to provide different temperature/time profiles for different areas of the circuit board or assembly to be cured. 
     In various embodiments, mechanical movement of the heater and/or the component to be cured may be utilized to provide a relative increase in heating and/or cooling rates, for example by bringing the assembly or circuit board to be cured into contact with a relatively hot heater to increase the heating rate and/or by separating the assembly or circuit board from the heater after curing is complete to increase the cooling rate. For example,  FIG. 8  shows an embodiment of a curing apparatus incorporating a heater portion  810  and a mounting portion  820  in accordance with embodiments of the present invention. In the apparatus shown in  FIG. 8 , heater portion  810  may be kept relatively hot and then be mated with or brought into proximity to mounting portion  820  to provide an increased heating rate to achieve the desired curing temperature more quickly. After curing is complete, heater portion  810  may be separated from mounting portion to provide relatively fast cooling. In various embodiments, heater portion  810  may move while mounting portion  820  is fixed, or heater portion  810  may be fixed and mounting portion  820  may move, or both heater portion  810  and mounting portion  820  may be movable. In various embodiments, a support  830  may be provided as part of mounting portion  820  to provide support for substrate  120 .  FIG. 8  shows mounting support  830  extending across all of substrate  120 ; however, this is not a limitation of the present invention, and in other embodiments support  830  may support only one or more portions of substrate  120 , for example to provide reduced thermal resistance between heater  290  and substrate  120 . 
     In various embodiments, pressure cure systems in accordance with embodiments of the present invention may be used to manufacture lighting systems that include, for example, light-emitting elements (LEEs) disposed on a rigid or flexible circuit board. In various embodiments, the pressure cure system may be used to cure ACA for LEE applications as described in the &#39;973 application. In various embodiments, such lighting systems may include an array of LEEs and optionally one or more control elements, for example to control or regulate the current to the LEEs, for example as described in U.S. patent application Ser. No. 13/799,807, filed on Mar. 13, 2013, and U.S. patent application Ser. No. 13/970,027, filed on Aug. 19, 2013, the entire disclosure of each of which is incorporated by reference herein. In various embodiments, the LEEs may include, consist essentially of, or consist of light-emitting diodes (LEDs) that may emit light in a relatively narrow spectral range to produce various colors such as red, green or blue, or that may emit white or substantially white light, for example having a correlated color temperature in the range of about 1800K to about 20,000K. 
     In various embodiments of the present invention, one or more additional materials may be positioned between the membrane and the assembly (e.g., the components being bonded and the substrate to which they are being bonded). For example, in various embodiments one or more films may be positioned between the membrane and the assembly, such that after curing, the film is adhered to and disposed over the assembly (e.g., disposed over the components on the circuit board). In various embodiments of the present invention, the film may cover one or more or all components and/or all or substantially all or one or more portions of the substrate. In various embodiments, the film may include, consist essentially of, or consist of one sheet of material before curing; however, this is not a limitation of the present invention, and in other embodiments the film may include, consist essentially of, or consist of two or more sheets or layers. For example, the film may include, consist essentially of, or consist of two or more sheets positioned adjacent to each other and/or more than one sheet positioned over all or a portion of another sheet. In various embodiments, the film may provide various advantageous attributes to the assembly after curing. For example, the film may facilitate the ability to achieve a specific stiffness or flexibility level of the assembly, to achieve a desired flammability rating of the assembly, to achieve a desired level of protection of the assembly (e.g., protection from mechanical forces such as impact, shear, abrasion, and the like), and/or to provide ingress protection (e.g., from dirt, particles, liquid, water, water vapor, and the like). In various embodiments of the present invention, the film may conformally or substantially conformally cover the assembly after curing. For example, the film may conformally cover one or more components on or in the assembly; however, this is not a limitation of the present invention, and in other embodiments the film may not be conformal or may not be substantially conformal. 
       FIG. 9A  shows a schematic of one embodiment of the present invention prior to curing. The configuration shown in  FIG. 9A  is similar to that shown in  FIG. 2A , but with the addition of a film  910  positioned under membrane  210 . As shown in  FIG. 9A , film  910  is positioned over at least a portion of one or more components  280 , conductive traces  160 , and substrate  120 ; however, as discussed herein, this is not a limitation of the present invention, and in other embodiments film  910  may have different relationships to the positions of components  280 , conductive traces  160 , and/or substrate  120 . Below film  910  is a region  911 .  FIG. 9B  shows the structure of  FIG. 9A  after curing and after removal of membrane  210 . As shown, after curing the file  910  may substantially conformally coat at least a portion of one or more components  280 , and/or at least a portion of one or more conductive traces  160 , and/or at least a portion of substrate  120 . 
     In various embodiments of the present invention, film  910  may be a curable film. In various embodiments of the present invention, film  910  and adhesive  205  may be cured together in a single cure cycle. For example, in various embodiments, adhesive  205  may be cured to adhere and electrically couple a component to an underlying circuit board and, within the same cure cycle, film  910  may be cured to form a layer (e.g., a protective layer) over the components and the circuit board. 
     In various embodiments curing of film  910 , for example with heat, radiation (e.g., infrared or ultraviolet or visible radiation or the like), or by other means, may induce physical or chemical cross-linking within film  910 . In various embodiments, film  910  may be a thermoset material, while in other embodiments film  910  may be a thermoplastic material. In various embodiments curing of film  910  may include melting or partial melting and subsequent solidification. In various embodiments, film  910  may be flexible or substantially flexible, while in other embodiments film  910  may be rigid or substantially rigid. In various embodiments, film  910  may be transparent to a wavelength of light emitted by a light-emitting component (e.g., an LEE) below the film  910 . In various embodiments, film  910  may have a transmittance greater than about 50%, or greater than about 75%, or greater than about 90%, or greater than about 95%, to a wavelength of light emitted by the light-emitting component. In various embodiments, the temperature for curing of a structure including film  910  may occur in a temperature range of about 50° C. to about 250° C., or in the range of about 80° C. to about 170° C., or in the range of about 100° C. to about 150° C. In various embodiments, the time for curing of a structure including film  910  may be in the range of about 1 minute to about 2 hours, or in the range of about 5 minutes to about 1 hour, or in the range of about 7 minutes to about 45 minutes. 
     In various embodiments of the present invention, film  910  may include, consist essentially of, or consist of one or more of the following materials: ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), ethylene tetrafluoroethylene (ETFE), polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate, polyethersulfone, polyimide, polyethylene, acrylic, plastic, or the like. In various embodiments, film  910  may include, consist essentially of, or consist of an aromatic TPU or an aliphatic TPU. 
     While  FIG. 9B  shows film  910  having a thickness that is relatively small compared to the height of the components on the circuit board, this is not a limitation of the present invention, and in other embodiments, film  910  may have any thickness. For example, in various embodiments, film  910  may have a thickness greater than the height of one or more of the components on the circuit board. In various embodiments, film  910  may act to planarize or substantially planarize the surface of the structure, for example as shown in  FIG. 9C . In various embodiments, film  910  may have a thickness in the range of about 10% to about 500% of the thickness of a component on the circuit board. In various embodiments, film  910  may have a thickness in the range of about 10 μm to about 10 mm, or in the range of about 100 μm to about 1 mm; however, in other embodiments film  910  may have a different thickness or may have a variable thickness across its area. 
     In various embodiments of the present invention, film  910  may be configured to protect the underlying components, e.g., components  280  or other components and/or the circuit board or substrate itself, for example to provide mechanical protection, protection from dust, water, etc. One method for rating different levels of environmental protection is an IP rating as specified by International Protection Marking in International Electrotechnical Commission (IEC) standard 60529, providing classification of degrees of protection provided by enclosures for electrical equipment, the entirety of which is hereby incorporated by reference herein. In various embodiments of the present invention, the structures of  FIGS. 9B and 9C  may have any IP rating, for example from IP00 to IP 69k, or any other IP rating. In various embodiments of the present invention, the structures of  FIGS. 9B and 9C  may have an IP 44 rating, an IP65 rating, an IP66 rating, an IP67 rating, or an IP68 rating. In general for an IP XY rating, “X” indicates the level of protection for access to electrical parts and ingress to solid foreign objects, while “Y” indicates the level of protection for ingress of harmful water. For example, an IP44 rating provides access and ingress protection for objects greater than about 1 mm and protection from water splashing on the system. In another example, an IP66 rating provides a dust-tight enclosure and protection from water jets incident on the system. Specific details of the requirements and test method are detailed within the IP specification. After provision of the film  910 , the substrate  120  and the components bonded thereto may be separated from base  230 . 
     In various embodiments, a film  920  may be disposed on the back of the structure (e.g., on the surface of substrate  120  opposite the surface on which the components  280  are bonded), for example to provide additional protection or to meet certain aesthetic or handling concerns. For example, in  FIG. 9D  film  920  is disposed on the back of the substrate while film  910  is disposed on the front of the substrate. In various embodiments, film  910  may have the same or substantially the same thickness as film  920 ; however, this is not a limitation of the present invention, and in other embodiments film  910  may be thicker or thinner than film  920 . In various embodiments, the substrate may be enclosed or encapsulated by films  910  and  920 , as shown in  FIG. 9E . In various embodiments, film  910  may cover less area of the substrate than film  920 , as shown in  FIG. 9D ; however, this is not a limitation of the present invention, and in other embodiments film  910  may cover the same, substantially the same or more area of the substrate than is covered by film  920 . The type of material, thickness, cure temperature, hardness, transmittance, and color of films  910 ,  920  are not limitations of the present invention. 
     In various embodiments, film  910  and/or  920  may have features formed in or on them before being attached to the circuit board. For example film  910  may have bumps, protrusions, recesses, or other features which may fit over one or more components  280 . For example,  FIG. 9F  shows film  910  having bumps  914  after curing. In various embodiments, the shape of the bumps may be the same or substantially the same after curing as before curing; however, this is not a limitation of the present invention, and in other embodiments the shape may change during and/or after curing. In various embodiments, shaped films such as shown in  FIG. 9F  may include, consist essentially of, or consist of at least one of the following: ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), ethylene tetrafluoroethylene (ETFE), polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate, polyethersulfone, polyimide, polyethylene, acrylic, plastic, or the like. While  FIG. 9F  shows bumps  914  having a dome shape this is not a limitation of the present invention, and in other embodiments bumps  914  may have other shapes, for example cubic, that of a rectangular solid, or the like. While  FIG. 9F  shows the interior surfaces of bumps  914  not in contact with components  280 , this is not a limitation of the present invention, and in other embodiments all or a portion of the inner surface of bumps  914  or film  910  may contact components  280 . 
     In various embodiments of the present invention, regions  914  (containing the shapes or bumps) and/or regions  915  (not containing the shapes or bumps) of film  910  may have additional features. For example, a material  916  may be applied to either the top and/or bottom surface of film  910  in either or both of portions of regions  914  and  915 .  FIG. 9G  shows material  916  applied to the bottom surface of film  910  in regions  915 . In various embodiments, material  916  may include, consist essentially of, or consist of an adhesive, for example a material used to adhere film  910  to the underlying substrate such as an epoxy, glue, or other bonding agent. In various embodiments of the present invention, material  916  may include, consist essentially of, or consist of an ink, for example a colored ink, to provide the finished product with a specific color or appearance. For example, in various embodiments material  916  may include, consist essentially of, or consist of a white ink. In various embodiments, inks may be applied to the top and/or bottom surface of film  910 . In various embodiments, material  916  may be applied to all or portions of the interior and/or outer surface of the shaped regions  914 . For example, in various embodiments material  916  may include, consist essentially of, or consist of a diffusing material, for example a diffusing ink, to diffuse the light from light-emitting components  280 . In various embodiments of the present invention, material  916  may have holes defined therein at one or more of the positions of components  280 , such that material  916  does not cover such components  280 . 
     In various embodiments, shapes or bumps  914  may be shaped as or may include, consist essentially of, or consist of an optical element, for example a refractive optic, a reflective optic, a total internal reflection optic, a Fresnel optic, or other types of optics. Such optics may be utilized to modify the spatial light distribution pattern of one or more light-emitting components  280 , for example to form a collimated beam, to form a wide angle beam, or to form any other spatial light distribution pattern. In various embodiments of the present invention, the optical elements may be coupled into or parts of a continuous material or film, for example as shown in  FIG. 9G , or they may be separate optical elements that are positioned over components  280 , for example as shown in  FIG. 9H . In  FIG. 9H , optical elements  917  are attached to the circuit board using material  918 , which may be similar to film  910  and in various embodiments may include, consist essentially of, or consist of one or more of the following: ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), ethylene tetrafluoroethylene (ETFE), polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate, polyethersulfone, polyimide, polyethylene, acrylic, plastic, or the like. In various embodiments, material  918  may include, consist essentially of, or consist of an aromatic TPU or an aliphatic TPU. In various embodiments of the present invention, optical elements  917  may be held in place with a local adhesive, that is an adhesive that is disposed only in the region of optical elements  917  and that does not cover all or substantially all of the substrate. While  FIG. 9H  shows discrete optical elements  917 , this is not a limitation of the present invention, and in other embodiments optical elements  917  may be part of a larger element, for example similar to material  910  shown in  FIG. 9G . 
     In various embodiments of the present invention, optical elements  917  or bumps  914  may be separated from components  280 , such that they are not optically coupled to component  280 . For example, in various embodiments component  280  may include, consist essentially of, or consist of an LEE and optical element  917  or bump  914  may be shaped and disposed over LEE  280  such that optical element  917  or bump  914  is not optically coupled to LEE  280  or to the emission area of LEE  280 . However, this is not a limitation of the present invention, and in other embodiments optical element  917  or bump  914  may be coupled to component  280  or to LEE  280  or to the emission area of LEE  280 . 
     In various embodiments of the present invention, the force applied to component  280  may be determined from the pressure within the chamber (or the pressure applied to membrane  210 ) and the surface area over which the pressure is applied or partially applied, for example the top surface area of component  280  or the area of contact(s)  285 . For example, if the desired force on the component is given by about F gm, and the top area of component  280  is about A cm 2 , then the force per unit area desired on component  280  is approximately F/A gm/cm 2 . In various embodiments, this force may be achieved on the component by applying a gas or fluid pressure of approximately F/A gm/cm 2 , e.g., in chamber  250 , for example when membrane  210  conforms or substantially conforms to the shape of the component. For example, in one embodiment of the present invention, component  280  is a 3014 SMD LED module, and the desired curing force is about 300 gm. The LED has a length of about 0.3 cm and a width of about 0.14 cm. The top area of the LED is about 0.042 cm 2 . Thus, the desired pressure on the LED is about 7140 gm/cm 2 . Converting this to pounds per square (psi) inch gives a value of about 100 psi of gas pressure that may be applied in chamber  250  to achieve the desired force of about 300 gm on the LED. In various embodiments of the present invention, the pressure applied within chamber  250  may be in the range of about 5 psi to about 1000 psi, or in the range of about 15 psi to about 300 psi, or in the range of about 80 to about 200 psi; however, the pressure applied in the chamber is not a limitation of the present invention, and in other embodiments the pressure may have any value. In various embodiments of the present invention, component  280  is a chip-scale package (CSP) LED having two rectangular contacts each about 0.05 cm by about 0.02 cm in size. The total contact area is 2×0.5×0.2 cm 2 , or about 0.002 cm 2 . Assuming the desired curing force is about 5 gm, the pressure is about 5 gm/0.002 cm 2  or about 2500 gm/cm 2 , or about 36 psi. While the preceding discussion utilizes pressure applied above or to membrane  210 , such pressure may also be applied by introducing a negative pressure (e.g., vacuum) under the membrane, for example in region  212 , alone or in combination with a pressure above membrane  210 . 
     As discussed herein, in various embodiments of the present invention, for a pliant or conforming membrane  210 , the force applied to a component may be determined approximately by multiplying the pressure applied to membrane  210  by the component surface area or top area. In various embodiments of the present invention, the force applied to a component may be increased by modifying the properties of membrane  210  and/or by interposing a force modifier between membrane  210  and the component. In various embodiments of the present invention, the force modifier is rigid and does not deform during the curing process. In various embodiments of the present invention, the force modifier may partially deform during the cure process.  FIG. 10A  shows a schematic of an adhesive curing apparatus in accordance with embodiments of the present invention that includes a force modifier  1010 . In various embodiments of the present invention, force modifier  1010  has a surface area A fm  larger than the surface area A c  of an underlying component, in this example component  281 . When pressure is applied to membrane  210 , the force on component  281  is given approximately by P×A fm , while the force on component  280  is given approximately by P×A c . Thus, the force applied to component  281  is larger than the force applied to component  280  by approximately the ratio A fm /A c . The use of force modifiers may permit a decoupling of the force applied to a component from the component&#39;s surface area or may permit an increase in force applied to one or more components without increasing the pressure on membrane  210  and/or on other components. In various embodiments of the present invention, force modifier  1010  may include, consist essentially of, or consist of plastic, glass, PET, paper, fabric, or the like. In various embodiments, force modifier  1010  may have a Young&#39;s modulus in the range of about 0.01 N/m 2  to about 200 N/m 2 . In various embodiments, the force modifier may be attached to, adhered to, or placed on the component before formation of membrane  210  over the assembly to be cured. In various embodiments of the present invention, one or more force modifiers may be part of membrane  210 , for example adhered or attached to membrane  210 , or part of membrane  210 , and aligned with the desired component or components when membrane  210  is disposed over the assembly to be cured. In various embodiments of the present invention, the force modifier is not part of the final product (and may thus be removed after curing); however, in other embodiments the force modifier may remain on the component. 
     In various embodiments, a force modifier membrane  1020  having a stiffness larger than that of membrane  210  may be interposed between membrane  210  and the component to provide the same function as force modifier  1010 .  FIG. 10B  is a schematic showing an adhesive curing apparatus in accordance with embodiments of the present invention that includes a force modifier membrane  1020 . In various embodiments of the present invention, force modifier membrane  1020  may flex or partially conform to the shape of the components, but because force modifier membrane  1020  does not fully or substantially conform to the shape of the components, the effective area over which the pressure is applied is larger than for the compliant membrane  210  (e.g., as shown in  FIG. 2A ). In various embodiments of the present invention, membrane  210  may be used in conjunction with force modifier membrane  1020 , for example to aid in sealing of region  212 ; however, in other embodiments, force modifier membrane  1020  may be used without membrane  210 . In various embodiments, the properties of membrane  210  may be varied to achieve a force multiplication, for example by using a stiffer material and/or a thicker layer for membrane  210 . 
     In various embodiments, the force modifier  1010  or force modifier membrane  1020  may have a relatively low thermal conductivity, for example to prevent heat dissipation through membrane  210  (e.g., when the heat source is below the assembly to be cured). In various embodiments, the force modifier may have a relatively high thermal conductivity, for example to aid in heat transfer to the component and adhesive (e.g., when the heat source surrounds or is over the assembly to be cured). 
     In various embodiments, substrate  120  may include, consist essentially of, or consist of a semicrystalline or amorphous material, e.g., polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polycarbonate, polyethersulfone, polyester, polyimide, polyethylene, plastic, glass, metal, fabric, cloth and/or paper. Substrate  120  may have multiple layers, e.g., a deformable layer over a rigid layer, for example, a semicrystalline or amorphous material, e.g., PEN, PET, polycarbonate, polyethersulfone, polyester, polyimide, polyethylene, and/or paper formed over a rigid substrate for example comprising, acrylic, aluminum, steel and the like. Depending upon the desired application for which embodiments of the invention are utilized, substrate  120  may be substantially optically transparent, translucent, or opaque. For example, substrate  120  may exhibit a transmittance or a reflectivity greater than 80% for optical wavelengths ranging between approximately 400 nm and approximately 600 nm. In some embodiments, substrate  120  may exhibit a transmittance or a reflectivity of greater than 80% for one or more wavelengths emitted by an LEE attached thereto. Substrate  120  may also be substantially insulating, and may have an electrical resistivity greater than approximately 100 ohm-cm, greater than approximately 1×10 6  ohm-cm, or even greater than approximately 1×10 10  ohm-cm. In various embodiments substrate  120  may be flexible, while in other embodiments substrate  120  may be rigid or semi-rigid. The flexibility of substrate  120  is not a limitation of the present invention. In various embodiments, substrate  120  may include, consist essentially of, or consist of fiberglass, FR4, FR2, or a metal core printed circuit board (MCPCB). In various embodiments, the substrate  120  is “flexible” in the sense of being pliant in response to a force such that the substrate may be easily bent or otherwise deformed without damage thereto. The substrate  120  may also be resilient, i.e., tending to elastically resume an original configuration upon removal of the force. In some embodiments, a flexible substrate  120  is configurable to a radius of curvature of about 1 m or less, or about 0.5 m or less, or even about 0.1 m or less. In some embodiments, flexible substrate  120  has a Young&#39;s Modulus less than about 100 N/m 2 , less than about 50 N/m 2 , or even less than about 10 N/m 2 . In some embodiments, a flexible substrate  120  has a Shore A hardness value less than about 100; a Shore D hardness less than about 100; and/or a Rockwell hardness less than about 150. The substrate material is not a limitation of the present invention. 
     In various embodiments, conductive traces  160  may include or consist essentially of silver, gold, aluminum, chromium, copper, and/or carbon, or a conductive ink, which may include one or more elements such as silver, gold, aluminum, chromium, copper, and/or carbon. The conductive trace material is not a limitation of the present invention. 
     The terms and expressions employed herein are used as terms and expressions of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive.