Patent Publication Number: US-2011068452-A1

Title: Low cost die placement

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of prior U.S. patent application Ser. No. 12/236,972, filed Sep. 24, 2008, which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to assembly of semiconductor devices and, more particularly, to the assembly of integrated circuit elements. 
     BACKGROUND OF THE INVENTION 
     As market demand increases for integrated circuit (IC) products such as RFID tags, and as IC die sizes shrink, high assembly throughput rates for very small die and low production costs are crucial in providing commercially-viable products. For example, the cost of an RFID device still depends on assembly complexity. 
     Conventional methods for assembling IC products include pick and place techniques. Such techniques involve a manipulator, such as a robot arm, to remove IC dies from a wafer and place them into a die carrier. The dies are subsequently mounted onto a substrate with other electronic components, such as antennas, capacitors, resistors, and inductors to form an electronic device. However, these techniques have drawbacks and disadvantages. For example, the pick and place techniques involve complex robotic components and control systems that handle only one die at a time. In addition, pick and place techniques have limited placement accuracy, and have a minimum die size requirement. 
     Thus, there is a need to overcome these and other problems of the prior art and to provide controllable methods for a scalable and low cost assembly in receiving, storing, and releasing electronic device elements. 
     SUMMARY OF THE INVENTION 
     In accordance with the present teachings, a method for assembling integrated circuits is provided. 
     The method can include forming one or more spaced elements on an oxide layer, the oxide layer formed on a silicon substrate; providing a release member comprising a phase-change material; joining the phase change material of the release member with the one or more spaced elements; removing the silicon substrate by etching the oxide layer; and exposing the joined phase change material to an energy for selectively releasing the one or more spaced elements from the release member. 
     In accordance with the present teachings, a method for assembling integrated circuits is provided. 
     The method can include forming one or more spaced IC elements on an oxide layer, the oxide layer formed on a silicon substrate; coupling an intermediate transfer member onto a first surface of the one or more spaced IC elements; removing the silicon substrate by etching away the oxide layer and exposing a second surface of the one or more spaced IC elements, wherein the second surface is substantially parallel to the first surface; coupling a phase change surface of a release member onto the exposed second surface of the one or more spaced IC elements; removing the intermediate transfer member from the first surface of the one or more spaced IC elements; and exposing the coupled phase change material to an energy for selectively releasing the one or more spaced IC elements from the release member. 
     In accordance with the present teachings, a method for assembling integrated circuits is provided. 
     The method can include forming a silicon layer on a phase change material of a release member; forming a plurality of bump bonds on the silicon layer of the release member; forming one or more spaced dies on the phase change material by etching through the silicon layer, wherein each spaced die comprises one or more bump bonds formed on an etched silicon layer; and exposing the phase change material to an energy to induce a phase change for selectively releasing the one or more spaced dies from the release member. 
     In accordance with the present teachings, a method for controlling assembly of IC elements is provided. 
     The method can include coupling one or more IC elements onto a phase change material of a release member; selectively inspecting a group of the one or more IC elements on the phase change material; and selectively applying an energy to a portion of the phase change material to release an inspected IC element for repair. 
     In accordance with the present teachings, an integrated circuit sub-assembly is provided. 
     The sub-assembly can include a release member supporting one or more transferred IC elements; an activatable thermal barrier layer formed on the release member, wherein the activatable thermal barrier material is provided between the one or more IC elements and the release member; and an energy source directed at said activatable thermal barrier layer, wherein said energy source activates said activatable thermal barrier layer and releases each transferred IC element from the release member. 
     Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. 
         FIG. 1  depicts an exemplary method for coupling and releasing IC elements using a phase change material in accordance with the present teachings. 
         FIGS. 2A-2C  depict an exemplary embodiment for assembling IC elements at various stages based on the method depicted in  FIG. 1  in accordance with the present teachings. 
         FIGS. 3A-3D  depict another exemplary embodiment for assembling IC elements at various stages based on the method depicted in  FIG. 1  in accordance with the present teachings. 
         FIG. 4  depicts an exemplary method for assembling IC elements using a phase change material and silicon on insulator (SOI) wafer in accordance with the present teachings. 
         FIGS. 5A-5D  depict an exemplary assembly process based on the method depicted in  FIG. 4  in accordance with the present teachings. 
         FIG. 6  depicts another exemplary method for assembling IC elements using a phase change material, an SOI wafer and an intermediate transfer member in accordance with the present teachings. 
         FIGS. 7A-7E  depict an exemplary assembly process based on the method depicted in  FIG. 6  in accordance with the present teachings. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the invention. The following description is, therefore, merely exemplary. 
     While the invention has been illustrated with respect to one or more implementations, alterations and/or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular function. Furthermore, to the extent that the terms “including”, “includes”, “having”, “has”, “with”, or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.”The term “at least one of” is used to mean one or more of the listed items can be selected. 
     Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of “less than 10” can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of 10, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than 10, e.g., 1 to 5. In certain cases, the numerical values as stated for the parameter can take on negative values. In this case, the example value of range stated as “less that 10” can assume negative values, e.g. −1, −2, −3, −10, −20, −30, etc. 
     Exemplary embodiments provide methods and systems for assembling electronic devices, such as integrated circuit (IC) chips. For example, IC elements/components can be selectively and scalably received, stored, inspected, repaired and released during the assembly of IC chips. As disclosed herein, exemplary IC elements can include, but are not limited to, display elements, detector elements, processor elements, or any other IC elements as would be understood by one of ordinary skill in the art. 
     For ease of illustration, the invention will be described with reference to an assembly of IC chips in an exemplary form of radio frequency identification (RFID) chips. RFID chips can be used in various applications, such as inventory control, airport baggage monitoring, as well as security and surveillance applications for location monitoring and real time tracking of such items. Generally, an RFID chip can include, e.g., a plurality of die elements (dies) mounted onto related electronics that can be located on a chip substrate. The plurality of dies can be an integrated circuit that performs RFID operations known to one of ordinary skill in the art, such as communicating with one or more chip readers according to various interrogation protocols of RFID. 
     As disclosed herein, the assembly of the exemplary RFID chips can include a low cost die placement by using a release member that has a phase-change surface. For example, in some embodiments, the die placement can include a combined use of one or more of the release member, an SOI (silicon on insulator) wafer, and an intermediate transfer member. In other embodiments, the die placement can include a combined use of the release member and a die release wafer. Even further, it will be appreciated the placement of die on a surface can be such that the die are magnetically aligned prior to subsequent processing. An example of the magnetic alignment of the die is disclosed in, for example commonly owned published application number 2006-0131504, and incorporated herein by reference in its entirety. 
     As used herein and unless otherwise specified, the term “release member” refers to a layered structure that includes a phase-change material formed over a release support. The term “release member” can be used to receive dies (i.e., attach dies) and, whenever desired, to release (i.e., detach) the received dies to a subsequent surface. The “release member” can be flexible or rigid and can be in a form of, for example, a web, a film, a plate, a roll, or their various combinations. 
     As used herein, the term “flexible” refers to the ability of a material, structure, device or device component to be deformed into a curved shape without undergoing a transformation that introduces significant strain, such as strain characterizing the failure point of a material, structure, device, or device component. The release member can therefore include, but is not limited to, a flexible web, flexible film, flexible plate, flexible sheet, flexible roll, and their various combinations. The flexibility of the disclosed release member can allow the attached IC elements to be wrapped, for example, around a mandrel and to render curved surfaces for a further storage or a roll-to-roll process. Likewise, the release support of the release member can be flexible or rigid and can be formed with various shapes for the release member. The release support can be formed of a material including, but not limited to, glass, plastic, stainless steel, fabric, paper, a fibrous material, a tape material (as known in the art) or their various combinations. In various embodiments, the release support can be a light weight release support. 
     The release member can include phase-change materials. As used herein, the term “phase change materials” refers to materials that can be switched between “phases”, for example, between generally amorphous and generally crystalline states. These materials can absorb energies such as optical, electrical, thermal, radiative or other energy that can induce and switch the material between its different states. The “phase-change materials” can be used as a functional interface between dissimilar materials, for example, between the release member and any IC elements. Specifically, when IC elements contact a phase-change material, the phase-change material can be adhesive to allow IC elements to be held in place, and can later allow the IC elements to be released from the release member using various energy sources, for example, optical beams from sources, such as UV, or IR lasers. When releasing, the IC elements can be transferred onto a subsequent surface and the phase-change material can be removed from the release support. Such release support (e.g., glass) can often be reused, for example, by forming (e.g., depositing) a “new” layer of phase-change material thereon to form a “new” release member. Therefore, the phase-change material can provide reworkability, ease of handling, and not require a cure in a high volume setting for IC elements. 
     In various embodiments, the phase change material can be designed according to the type and power of the energy sources that can be used to induce the phase change. For example, one or more metal elements can be included in the phase change material, such as, for example, tin, palladium, aluminum, silicon, germanium, tellurium, antimony, indium, silver, tellurium, antimony, gallium, lanthanide, and chalcogenide. The phase change material can therefore include various metals, metal alloys and/or metal compounds of a combination to trip at a predetermined temperature to conduct the phase change. Tolerances of ±1-2° C. can be obtained. For example, metal compounds can include compounds of Ga, La, and S (GLS), as well as related compounds in which there is substitution of S with 0, Se and/or Te. 
     By using the phase-change material, the release member can be used to receive IC elements, and to further release IC elements to any desired subsequent receiving surface (e.g., an intermediate transfer type surface or a final chip surface). In addition, the release member can be used to store the received IC elements in various flexible or rigid forms. For example, the release member can be used for a display including, but not limited to, TV screen, radiographic detector, and/or sensor array. Such display can be flat or arcuate, and can be used, e.g., to emit, detect and/or collect energy. 
       FIG. 1 ,  FIGS. 2A-2C , and  FIGS. 3A-3C  depict various embodiments for transferring IC elements using a release member having a phase change surface in accordance with the present teachings. Specifically,  FIG. 1  depicts an exemplary method  100  for coupling and releasing IC elements using the release member, while  FIGS. 2A-2C  and  FIGS. 3A-3C  depict various exemplary embodiments for assembling IC elements at various stages based on the method  100  depicted in  FIG. 1 . Although the method  100  will be described in reference to  FIGS. 2A-2C  and/or  FIGS. 3A-3C  for illustrative purposes, the process of method  100  is not limited to the structures shown in  FIGS. 2A-2C  and  FIGS. 3A-3C . 
     The method  100  begins at  110  in  FIG. 1 . At  120 , IC elements can be coupled with a release member through a phase change material formed on a release support. For example, a plurality of RFID dies can be coupled with the release member at the surface of the phase change material. In various embodiments, the phase change material can be patterned on the release support of the release member. Each patterned phase change material can be selectively used to couple one of the plurality of RFID dies. 
     Each exemplary RFID die can further include a plurality of contacts to provide an electrical connection of the RFID die with the related electronics for the RFID chips. The plurality of contacts can include, for example, conductive traces, such as conductive ink traces, or conductive bumps or bumps attached to a strap. In various embodiments, the exemplary conductive bumps can be formed on a die support, such as silicon. The conductive bumps can further be built up, if required by the assembly process, by the deposition of additional materials, such as gold and solder flux. Such “bumping” processes are known to one of ordinary skill in the relevant arts. 
     The plurality of dies (e.g., wherein each die includes a plurality bumps) can therefore be mounted in either a “bump side up” or “bump side down” orientation. As used herein the terms “bump side up” and “bump side down” denote alternative implementations of the plurality of dies. In particular, these terms designate the orientation of connection bumps in relation to a subsequent surface, such as a chip substrate. That is, in a “bump side up” orientation, the plurality of dies can be transferred to the subsequent surface with bumps facing away from the subsequent surface. In a “bump side down” orientation, the plurality of dies can be transferred to the subsequent surface with bumps facing towards, and in contact with the subsequent surface. 
     In various embodiments, the subsequent surface can be an intermediate transfer surface, or an actual final chip substrate to which the dies can be permanently attached. If the subsequent surface is not a final surface, the plurality of dies can be transferred to an intermediate surface, such as the surface of an intermediate transfer member as disclosed herein. In various embodiments, the subsequent surface can be rigid or flexible and can be formed from various materials chosen from, for example, plastic, fibrous material, glass, silicon wafer, etc., for either the intermediate surface or final chip substrate. 
     For example, in  FIG. 2A , device  200 A can allow for a “bump side up” release. As shown, the device  200 A can include a plurality of dies  250  formed on a release member  202  that can include a phase-change material  206  formed on a release support  204 . Each die  250  can include a plurality of bumps  255   a - d.    
     In another example, as shown in  FIG. 3A , device  300 A can allow for a “bump side down” release. As shown, the device  300 A can include a plurality of dies  350  formed on a release member  302 , wherein each die  350  can include a plurality of bumps  355   a - d , and the release member  302  can include a phase-change material  306  formed on a release support  304 . 
     Note that the plurality of bumps  255   a - d  in device  200 A and the plurality of bumps  355   a - d  in device  300 A are shown in a cross section view, wherein contact bumps  255   a - d  and/or  355   a - d  can be arranged in a rectangular shape that allows for flexibility in die placement, and good mechanical adherence between surfaces. In various embodiments, any number of contact bumps can be formed for devices  200 A and  300 A, depending on a particular application. In addition, contact bumps  255   a - d  and/or  355   a - d  can be laid out in other shapes in accordance with the present teachings. 
     Referring back to  FIG. 1 , at  130 , the release member that is coupled with IC elements can be exposed to an energy source to induce a phase change of the phase-change material, and thus to release the IC elements from the release member leaving the release support to be, for example, reused. And the method  100  concludes at  140 . 
     In the first exemplary embodiment of the method  100 , as shown in  FIG. 2A , in order to release the plurality of dies  250 , the device  200 A can be flipped upside down to have the bumps  255  face “up” with respect to the die  250  as shown in  FIG. 2B . The device  200 B can then be placed close to a subsequent surface  290  and/or in contact with the subsequent surface  290  as shown in  FIG. 2C . 
     In the second exemplary embodiment of the method  100 , as shown in  FIG. 3A , in order to release the plurality of dies  350  in  FIG. 3A , the device  300 A can be flipped upside down to have the bumps  355  face “down” with respect to the die  350  as shown in  FIG. 3B . The device  300 B can then be placed close to and/or in contact with a subsequent surface  390  as shown in  FIG. 3C . 
     The device  200 B (see  FIG. 2B ) and the device  300 B (see  FIG. 3B ) can then be exposed to an energy to induce a phase change of the phase-change material (e.g.,  206  or  306 ) of the release member (e.g.,  202  or  302 ). Because of the induced phase change, the plurality of dies can be released from the release member ( 202  or  302 ) (e.g., onto a prepared subsequent surface  290  or  390 ). In various embodiments, the energy source can be, for example, an optical source such as a laser beam of UV or IR. In the case when an optical energy is used, the release member (e.g.,  202  or  302 ), including the release support (e.g.,  204  or  304 ) can be at least partially transparent in order to transmit the optical signal onto the phase change material (e.g.,  206  or  306 ). 
     Specifically, in  FIG. 2C , the device  200 C can be exposed to, e.g., an IR laser beam  270 . When the IR laser beam  270  hits the phase-change material  206  of the release member  202 , the phase-change material  206  can absorb this laser energy by design and induce a phase change between its different states to release each of the plurality of dies  250  from the device  200 B (i.e., from the release support  204 ) to the subsequent surface  290 . Similarly, in  FIG. 3C , the device  300 C can be exposed to, e.g., an IR laser beam  370 . When the IR laser beam  370  hits the phase-change material  306  of the release member  302 , the phase-change material  306  can absorb this laser energy by design and induce a phase change between its different states to release each of the plurality of dies  350  from the device  300 B (i.e., from the release support  304 ) to the subsequent surface  390 . 
     The subsequent surface  290  or  390  can include an adhesive substance (not shown) formed on a substrate of the subsequent surface. The adhesive substance can be known to one of ordinary skill in the art and can be sufficient to hold the released elements in place on the subsequent surface and can also be easily transported carrying the attached IC elements. The subsequent surface can be an intermediate substrate and/or a final chip substrate. 
     In various embodiments, prior to releasing, the subsequent surface  290  or  390  can be placed in contact with the die elements and be pressed against the die elements that reside on the release member (e.g.,  202  in  FIG. 2C  or  302  in  FIG. 3C ) causing the elements to attach to the adhesively coated subsequent surface. When exposed to releasing energy, the phase change material (e.g.,  206  or  306 ) can undergo a phase change to release the die elements and can be removed, leaving the dies  250  or  350  attached to the subsequent surface (e.g.  290  or  390 ). In various embodiments, a conductive metal coating having, for example, a plastic or dielectric overlay can be formed on the subsequent surface, the metal coating electrically connecting with the bump bonds  355 . 
     In addition to that disclosed in connection with  FIGS. 3A-3C , the exemplary embodiment  300 D depicted in  FIG. 3D , indicates that one or more released IC elements  350  can be transferred onto an exemplary antenna substrate  318  or otherwise metal coated substrate  318 . 
     The released (i.e., detached) one or more dies  350 , e.g.,  350 B and  350 C shown in  FIG. 3D , transferred onto the antenna substrate  318  can have an electrically conductive contact with a plurality of antennas  315  through a plurality of bump bonds  355  of each transferred die  350 B or  350 C. 
     In various embodiments, a conductive adhesive or an activatable thermal barrier layer can be disposed between the antenna  315  of the chip substrate  310  and the bump bonds  355  of each die  350 B or  350 C. 
     As shown in  FIG. 3D , the transferred dies can be bonded with the antenna substrate  318  by using various application rollers  360 A/B to form bonded dies (e.g.,  350 B or  350 C) on the antenna substrate  318 . 
     In one embodiment, at least one pressure roller such as  360 A can be used to apply pressure to each transferred die  350  to provide a compressive pressure for bonding the bump bonds  355  of the die  350  with the underlying antenna substrate  318 . In various embodiments, more pressure rollers can be used. For example, a second pressure roller, feed, or idler roller  360 B can oppose the roller  360 A and be positioned on an opposite side of the chip substrate  310  to assist in bonding each die (e.g.,  350 B/C) with the antenna substrate  318 . 
     In another embodiment, at least one heating roller  360 A can be used to roll over each transferred die  350  to provide a thermal energy for bonding each transferred die with the underlying antenna substrate  318 . In various embodiments, more heating rollers can be used. For example, a second heating roller, feed, or idler roller  360 B can oppose the roller  360 A and be positioned on an opposite side of the chip substrate  310  to assist in bonding each die (e.g.,  350  B/C) with the antenna substrate  318 . 
     In an additional embodiment, each transferred die  350  can be bonded with the underlying antenna substrate  318  by applying both a compressive pressure and thermal energy using one or more of an exemplary roller  360 A and an exemplary roller  360 B. In addition, the compressive pressure and the heat can be applied by, for example, one or more pressure rollers and one or more heating rollers. In the event of multiple rollers formed in series, pressure and heat can then be applied either sequentially or simultaneously according to a positioning of rollers. 
     Subsequently, the bonded IC elements on the antenna substrate can be encapsulated in place using an encapsulating material, which can be a curable material including, but not limited to, polyurethane, polyethylene, polypropylene, polystyrene, polyester, and epoxy, and combinations thereof. The encapsulating material can be generally deposited over electronic components (e.g., dies  350 B or  350 C in  FIG. 3D ) mounted on a chip substrate (e.g., the antenna substrate  318 ) using, for example, a syringe-type dispenser moved over the chip substrate. For example, dams (e.g.,  375  in  FIG. 3D ) of high viscosity encapsulating material  380  can be first deposited around areas where components are bonded and then the areas within the dams can be cured by, for example, applying pressure, heat or radiation depending on the chosen encapsulating material. As still shown in  FIG. 3D , the exemplary bonded die  350 C can be locked in place on the antenna substrate  318  within the cured encapsulating material  375 . 
     In various embodiments, the acts of releasing, transferring, bonding, and encapsulating of the one or more IC elements illustrated in  FIG. 3D  can be performed simultaneously in a successive manner using, for example, a flexible sheet to sheet process or flexible roll to roll process. In this manner, a large amount of dies can be released, transferred, bonded and encapsulated selectively, successively, and simultaneously. 
     It is noted that the method  100  and the processes  200  and  300  can be implemented on any portion of, or all of the dies on the release member. For example, the method and processes can be accomplished in one or more iterations, using one or more strips of an adhesive coated on the subsequent substrate that each adhere to and carry away a group of dies from the release member. Alternatively, a sheet sized adhesive coated subsequent surface can be used to adhere to and carry away multiple groups or any size array of the dies from the release member. 
     In this manner, as described in  FIGS. 1-3 , the disclosed release member can provide a “controllable” technique for selectively receiving, storing, screening (inspecting), repairing, and/or releasing IC elements. First, the release member can provide a scalable high volume assembly of IC elements. For example, when glass is used for the release member, a glass release member can be formed having dimensions on an order of meters (e.g., about 2×2 square meters) or larger, while a traditional silicon wafer generally has a maximum diameter of, for example, about 8 inches. Second, the release member can have various flexible (e.g., curved) shapes and provide conformability for storing or further usage. Third, by using the release member, the assembly process of IC elements can be controlled. That is, a selective inspection and/or a selective repair can be performed prior to releasing of the IC elements from the release member. For example, a group of the IC elements on the phase change material can be selectively inspected using a test circuit based on specific applications. An inspected IC element that needs to be repaired can then be determined and selectively released from the release member by applying energy to a selected portion of the phase change material, to which the determined IC element is coupled. Fourth, when releasing, by using the phase change material, one or more selected IC elements or multiple IC elements can be released at a time. In addition, the disclosed releasing process of the IC elements can be performed continuously for all of the IC elements at a time or flexibly for a portion of the IC elements at a time. Finally, the geometry and distribution of the released IC elements can be selectively changed when transferring to the subsequent surface after releasing. 
     In various embodiments, the method  100  can be used to transfer IC elements between any two surfaces during the IC processes by using the phase change material on various surfaces. The transfer between any two surfaces can include, for example, transferring IC elements from a release member to an intermediate surface, transferring IC elements between multiple intermediate surfaces, transferring IC elements between an intermediate surface and the final substrate surface, and transferring IC elements from the release member to the final substrate surface. 
     In addition, the method  100  can be applicable and employed for a desired bump side up release or bump side down release according to a particular application. In various embodiments, the release member of the method  100  can be used in combination with an intermediate transfer member, an SOI wafer, and/or a release wafer for a desired release. 
       FIG. 4  and  FIGS. 5A-5D ,  FIG. 6 , and  FIGS. 7A-7E  depict various embodiments for releasing IC elements using the release member in accordance with the present teachings. For example,  FIG. 4  and  FIGS. 5A-5D , as well as  FIG. 6  and  FIGS. 7A-7E  show methods and processes for releasing IC elements using an SOI wafer and/or intermediate transfer member in accordance with the present teachings. 
     Specifically,  FIG. 4  depicts an exemplary method  400  for receiving and releasing IC elements using an SOI wafer and a release member, while  FIGS. 5A-5D  depict an exemplary process based on the method  400  in  FIG. 4  in accordance with the present teachings. Although the method  400  will be described in reference to  FIGS. 5A-5D  for illustrative purposes, the process of method  400  is not limited to the structures shown in  FIGS. 5A-5D . Beginning at  410  of the method  400 , at  420 , multiple spaced IC elements can be produced on an oxide insulator layer that is disposed on a silicon substrate. In various embodiments, an SOI wafer can be used to form the multiple separated die elements. 
     For example, as shown in  FIG. 5A , the device  500 A can include a silicon substrate  510  having an overlying oxide insulator  520  and a thin silicon semiconductor layer  530  formed above the oxide layer  520 . The upper thin silicon layer  530  can have a thickness of about 5 microns or less by, for example, removing/etching a portion of silicon from an upper silicon layer of an SOI wafer as is recognized in the art. 
     IC elements can then be formed from the thin silicon layer  530  of the device  500 A. For example, a plurality of bumps  555  can be formed on the thin silicon layer  530  to form a plurality of dies  550 . The plurality of dies  550  can be further separated from one another on the oxide layer  520  (see device  500 B of  FIG. 5B ). The separation between the dies  550  can be performed by suitable patterning and etching processes known to one of ordinary skill in the art to remove portions of silicon (that are located between any two adjacent dies  550 ) through the thin silicon layer  530 . 
     At  430  in  FIG. 4 , a release member can then be coupled with the multiple separated IC elements (e.g., dies) by laminating the phase change material of the release member onto the surface (defined as “first surface”) of the exemplary multiple die elements. 
     As shown in  FIG. 5C , a release member  502  can be positioned in contact with a first surface of the device  500 B that has a plurality of dies  550 . For example, the phase-change material  506  of the release member  502  can contact the plurality of dies  550  and hold the plurality of dies  550  in place as shown in  FIG. 5C . 
     At  440 , the silicon substrate can then be removed by etching away the oxide insulator layer that is disposed between the multiple separated IC elements and the silicon substrate. 
     For example, as in  FIGS. 5C-5D , the silicon substrate  510  can be removed by etching away the oxide layer  520  using suitable etching techniques known to one of ordinary skill in the art and exposing a second surface of the plurality of dies  550 . Consequently, the device  500 D can include the release member  502  attached on the first surface of the plurality of dies  550 , which dies can be subsequently released, for example, onto an intermediate or final substrate, in a bump side up manner. 
     At  450  of  FIG. 4 , the device (e.g.,  500 D), having a similar structure as that shown in  FIG. 2B , can be processed by using the method  100  as described in  FIG. 1  and/or  FIGS. 2B-2C . For example, the device  500 D can be exposed to an energy beam  570  to induce the phase change of the phase change material  506  and further to release the plurality of dies  550  from the release member  502 . As similarly described in  FIGS. 2-3 , the released plurality of dies  550  can be transferred onto a subsequent surface for further processes depending on various specific applications. The method  400  concludes at  460  for further processes as known in the art. 
       FIG. 6  depicts another exemplary method  600  for receiving and releasing IC elements using an SOI wafer and an intermediate transfer member in accordance with the present teachings. For illustrative purposes, the method  600  will be described in reference to  FIGS. 7A-7E , although the method  600  is not limited to the structures shown in  FIGS. 7A-7E . 
     The method  600  begins at  610 . At  620 , one or more spaced IC elements can be formed on an oxide layer that is formed on a silicon substrate. In various embodiments, the one or more spaced IC elements can be formed from the upper silicon layer of an SOI wafer as is known to one of ordinary skill in the art. 
     For example, as shown in  FIG. 7A , a plurality of separated die elements  750  can be formed on an oxide layer  720  on a silicon substrate  710 . Each die element  750  can include a plurality of bumps  755  formed on a portion of a thin silicon layer  730 . Each portion of the thin silicon layer  730  can be formed by etching through an upper silicon layer that is formed on an oxide layer  720  on a silicon substrate  710 , for example, of an SOI wafer. The thin silicon layer  730  can have a thickness of, for example, about 5 microns. 
     At  630  in  FIG. 6 , an intermediate transfer member can be attached to the (first) surface of the one or more IC elements that is formed on the oxide layer of the exemplary SOI wafer. 
     As shown in  FIG. 7B , an intermediate transfer member  780  can be positioned to couple with a first surface of the device  700 A (see  FIG. 7A ) that has a plurality of dies  750  attached thereto. The intermediate transfer member  780  can be rigid or flexible to receive, release and/or transfer the plurality of dies  750 . The intermediate transfer member  780  can include an adhesive surface  786  formed on a transfer support  784 . In various embodiments, the transfer support  784  can be similar to the release support (e.g.,  204  in  FIG. 2 ,  304  in  FIG. 3 , or  504  in  FIG. 5 ) used for the disclosed release member (e.g.,  202  in  FIG. 2 ,  302  in  FIG. 3 , or  502  in  FIG. 5 ). In other embodiments, the transfer support  784  can use different materials from the release support of the release member. In yet other embodiments, the transfer support  784  can be flexible. The adhesive surface  786  can include one or more adhesive materials, such as, for example, an epoxy, glue, or wax applied thereto, to provide surface adhesiveness. In various embodiments, the intermediate transfer member  780  can be, for example, a green tape or a blue tape as known in the industry. In one embodiment when coupling, the intermediate transfer member  780  can be pressed against the plurality of separated dies  750  causing the dies  750  to attach thereto. The intermediate transfer member  780  can be moved away with the attached dies  750 . 
     At  640 , the silicon substrate can be removed by etching away the overlaying oxide layer and exposing a second surface of the one or more spaced IC elements. 
     For example, as shown in  FIG. 7B , the silicon substrate  710  can be removed by etching away the oxide layer  720  using suitable etching techniques known to one of ordinary skill in the art. This removal of the silicon substrate  710  and the oxide layer  720  can expose a second surface that is substantially parallel to the first surface of the plurality of dies  750  (see device  700 C in  FIG. 7C ). Consequently, the device  700 C can include an intermediate transfer member  780  attached to the first surface of the plurality of dies  750 . 
     At  650 , a release member having a phase change material formed on a release support can be provided. The phase change material can then be attached to the exposed second surface of the plurality of dies  750 . 
     As shown in  FIG. 7D , a release member  702  can be attached onto the second surface of the plurality of dies  750  (see device  700 C), wherein the second surface of the plurality of dies  750  joins and adheres with the phase-change material  706 , and subsequently can be released via an energy exposure as shown at  770 . 
     At  660 , the intermediate transfer member can be removed leaving the one or more IC elements attached to the release member. 
     As shown in  FIG. 7E , the intermediate transfer member  780  can be removed from the first surface of the plurality of dies  750  and the bump bonds  755  of each die  750  can be exposed (see  FIG. 7E ). As shown, the device  700 E can be similar to the device  300 A of  FIG. 3A . 
     At  670 , the one or more IC elements can then be released from the release member by applying an energy source to the phase-change material disposed between the one or more IC elements and the release support of the release member. 
     For example, as similarly described in  FIG. 1  and  FIGS. 3B-3C , the device  700 E can be flipped upside-down for a further releasing process, which can be, for example, a bump side down release. In an exemplary embodiment, the flipped device  700 E can be exposed to an energy beam  770  to induce the phase change of the phase change material  706  and further to release the plurality of dies  750  from the release member  702 . The released plurality of dies  750  can then be transferred onto a subsequent surface for further processes depending on various specific applications as described in  FIG. 1 . 
     The method  600  concludes at  680 . In various embodiments, the method and process in  FIG. 6  and  FIGS. 7B-7E  can be repeated as desired to receive, release and transfer IC elements. For example, the plurality of dies  750  can be transferred to any two surfaces for either a bump side up or a bump side down orientation by using one or more intermediate transfer members  780  and at least one release member  702 . 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.