Patent Publication Number: US-2010122654-A1

Title: Thermally controlled fluidic self-assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application is a Divisional of previously filed U.S. patent application Ser. No. 11/021,120, entitled: THERMALLY CONTROLLED FLUIDIC SELF-ASSEMBLY, filed on Dec. 22, 2004, in the names of Ravi Sharma et al., which is hereby incorporated herein by reference in its entirety. 
     Reference is made to commonly assigned, U.S. patent application Ser. No. 10/849,302, entitled: THERMALLY CONTROLLED FLUIDIC SELF-ASSEMBLY METHOD AND SUPPORT, filed on Sep. 3, 2004, in the names of Daniel D. Haas et al. (which was abandoned on Aug. 5, 2009); and U.S. patent application Ser. No. 10/849,329, entitled: THERMALLY CONTROLLED FLUIDIC SELF-ASSEMBLY AND CONDUCTIVE SUPPORT, filed on Sep. 3, 2004, in the names of Theodore K. Ricks et al. (which has since issued as U.S. Pat. No. 7,251,882, issued on Aug. 7, 2007). 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to methods for fluidic micro-assembled structure and, in particular, to methods and apparatuses for selective fluidic assembly of micro-components. 
     BACKGROUND OF THE INVENTION 
     Micro-assembled devices offer the promise of an entirely new generation of consumer, professional, medical, military, and other products having features, capabilities and cost structures that cannot be provided by products that are formed using conventional macro-assembly and macro-fabrication methods. For example, there is a need, particularly in the field of flat panel displays, smart cards and elsewhere, for microelectronic devices or chips that can be integrated into or assembled as either a system or as an array, in a relatively inexpensive manner. In another example, there is a need for a cost effective method for allowing accurate and cost effective assembly of colored display elements such as electrophoretic beads in specific locations on display panels. 
     One advantage of such micro-assembled devices is that they can utilize different materials and devices (a process generally termed heterogeneous integration) in ways that create new product possibilities. For example, such heterogeneous integration provides the opportunity for relatively rigid structures such as such as silicon transistors or other electronic devices to be assembled into more complex electronic circuits using a flexible substrate as opposed to the rigid silicon substrates currently used for this purpose. In this example, such heterogeneous integration would provide a less expensive means to assemble silicon based integrated circuit components and/or any other kind of circuit components to form integrated circuits on flexible or rigid supports that are not made from silicon. However, it will be appreciated that in providing such heterogeneous integrated circuits, it is necessary that these processes provide for precise placement of multiple types of independent structures on the substrate. Such heterogeneous integration can also be used for other purposes. For example, heterogeneous integration can be used for purposes such as the assembly of pharmaceutical products, advanced materials, optical structures, switching structures, and biological structures. 
     Of particular interest in the electronic industry is the potential for micro-assembly to solve existing problems in the assembly of highly desirable but complex structures used in forming electronic displays. Typical electronic displays use a structure known as a “front plane” as the image forming surface. The “front plane” comprises an arrangement of image forming elements also known as active elements formed from structures such as liquid crystals, electroluminescent materials, organic light emitting diodes (OLEDs), up converting phosphors, down converting phosphors, light emitting diodes, electrophoretic beads, or other materials that can be used to form images. Such active elements typically form images when an electric field or some other stimulus or other field is applied thereto. Such electronic displays also incorporate a structure known as a “back plane” that comprises structures such as electrodes, capacitors, transistors, conductors, and pixel drivers and other circuits and integrating components that are intended to provide appropriate stimulus to the active components to cause the active components to present an image. For example, the active components can react to stimulus by emitting controlled amounts of light or by changing their reflectivity or transmissivity to form an image on the front plane. 
     It is well known to use heterogeneous integration methods to place elements on a substrate. Such heterogeneous integration methods can be generally divided into one of two types: deterministic methods and random methods. Deterministic methods use a human or robotic structure to place individual elements into particular locations on the substrate. Such methods are also known as “pick and place” methods. Such “pick and place” methods offer two advantages: complete control and positive indication that components have been appropriately placed in a desired location. Further, such “pick and place” methods also allow the precise assembly of different types of micro-components to form a micro-assembled structure that integrates different types of materials, micro-assembled structures and components. 
     It will be appreciated that deterministic methods require a high degree of precision by the person or machine executing the deterministic assembly process. Accordingly, such deterministic methods are difficult to apply in a cost effective manner. This is particularly true where the assembly of micro-components is to occur at a high rate of assembly or where large-scale assembly of micro-components is to be performed such as is required in commercial, pharmaceutical, or other applications. 
     Random placement methods such as fluidic self-assembly have been used to integrate electronic devices such as GaAs LEDs onto silicon substrates. Fluidic self-assembly is a fabrication process whereby a large number of individual shaped micro-assembled structures are integrated into correspondingly shaped recesses on a substrate using a liquid medium for transport. This method of self-assembly relies on gravitational and shear forces to drive the self-assembly of micro-components. Examples of this include U.S. Pat. No. 5,545,291, entitled: METHOD FOR FABRICATING SELF-ASSEMBLING MICRO-ASSEMBLED STRUCTURES”, filed on Dec. 17, 1993, in the names of Smith et al.; U.S. Pat. No. 5,783,856, entitled: METHOD FOR FABRICATING SELF-ASSEMBLING MICRO-ASSEMBLED STRUCTURES, filed on May 9, 1995, in the names of Smith et al.; U.S. Pat. No. 5,824,186, entitled: METHOD AND APPARATUS FOR FABRICATING SELF-ASSEMBLING MICRO-ASSEMBLED STRUCTURES, filed on Jun. 7, 1995, in the names of Smith et al.; and U.S. Pat. No. 5,904,545, entitled: APPARATUS FOR FABRICATING SELF-ASSEMBLING MICRO-ASSEMBLED STRUCTURES, filed on Jun. 7, 1995, in the names of Smith et al. 
       FIG. 1A  illustrates, generally, the operation of one type of prior art random placement method. In  FIG. 1A , a substrate  10  is shown having binding sites in the form of recesses  21  that are shaped to accept correspondingly shaped micro-components  47  suspended in a fluid  29 . As is shown in  FIG. 1A , fluid  29  contains micro-components  47  and is applied to substrate  10 . When this occurs, gravity and/or other forces draw micro-components  47  onto substrate  10  and into recesses  21 . This allows for the assembly of micro-components  47  to substrate  10  using a massively parallel process that is more suitable for high volume and/or large-scale assembly processes. 
     Other approaches have been developed for using fluidic self-assembly to build a micro-assembled structure without relying exclusively on gravitational and/or shear forces. Some of these are illustrated in  FIGS. 1B-1E . In each of  FIGS. 1B-1E , a substrate  10  is shown having binding sites  22 - 25 . Binding sites  22 - 25  can take many forms, only some of which are shown in  FIGS. 1B-1E . 
     In  FIG. 1B , a fluidic self-assembly method is shown wherein a substrate  10  is provided having binding sites  22  that are adapted with hydrophobic patches that engage with hydrophobic surfaces  48  on micro-components  49  suspended in fluid  29  and thereby locate the micro-components  49  on substrate  10 . One example of this type is shown and described in U.S. Pat. No. 6,527,964, entitled: METHOD AND APPARATUSES FOR IMPROVED FLOW IN PERFORMING FLUIDIC SELF-ASSEMBLY, filed on Nov. 2, 1999, in the names of Smith et al. The &#39;964 patent describes a substrate that is exposed to a surface treatment fluid to create a surface on the substrate that has a selected one of a hydrophilic or a hydrophobic nature. A slurry is dispensed over the substrate. The slurry includes a fluid and a plurality of the micro-components. Two types of micro-components are provided: one that is designed to adhere to a hydrophilic surface associated with a co-designed receptor site and one that is designed to adhere to a hydrophobic surface associated with a co-designed receptor site. As the slurry is dispensed over the substrate  10 , the selectively hydrophilic surfaces of selected ones of the micro-components adhere to hydrophilic surfaces on substrate  10 , while not adhering to hydrophobic surfaces. Micro-components that have a hydrophilic surface engage hydrophilic patches on the substrate. Thus, micro-components are selectively placed in predefined locations on the substrate. 
       FIG. 1C  shows another fluidic self-assembly method. The method illustrated in  FIG. 1C  uses capillary forces for self-assembly. As is shown in  FIG. 1C , binding sites  23  are adapted with drops  32  of a liquid  34 . Capillary attraction between liquid  34  and surface  36  on micro-components  51  causes micro-components  51  suspended in fluid  29  to assemble on binding sites  23 . However, it will be appreciated that this method requires the precise placement of drops of liquid  34  on substrate  10  and does not necessarily provide the discrimination useful in the assembly of components having multiple types of micro-components. Various versions of this method are described generally in Tien et al. (J. Tien et al., “Crystallization of Millimeter-Scale Objects with Use of Capillary Forces”,  J. Am. Chem. Soc.,  Vol. 120, pp. 12670-12671, November 1998.) and U. Srinivasan et al., (U. Srinivasan et al., “Microstructure to Substrate Self-Assembly Using Capillary Forces”,  Journal of Microelectromechanical Systems,  Vol. 10, pp. 17-24, Mar. 2001). 
     In the prior art illustrated in  FIG. 1D , a fluidic self-assembly method is shown wherein binding sites  24  include magnetic patches that attract a magnetic surface  53  on micro-component  52  suspended in fluid  29 . Such an approach is described in Mukarami et al. (Y. Murakami et al., “Random Fluidic Self-Assembly of Microfabricated Metal Particles”,  The School of Materials Science, Japan Advanced Institute of Science and Technology,  1-1,  Asahidai, Tatsunokuchi, Ishikawa,  923-1292, Japan, and in  Proc.  1999  Int. Conf Solid-State Sensors and Actuators,  Sendai, Japan, Jun. 7-10, 1999, pp. 1108-1111.), which describes in greater detail the use of magnetic forces to assemble microscopic metal disks onto a substrate patterned with arrays of nickel dots. However, high cost is encountered in providing the arrays of disks on the substrate. Further such methods are typically limited to applications wherein the micro-assembled structures being assembled each have magnetic characteristics that permit the use of magnetic forces in this fashion. 
     Electrostatic attraction has been proposed for use in positioning micro-components during micro-assembly. U.S. Patent Application Publication No. 2002/0005294, entitled: DIELECTROPHORESIS AND ELECTRO-HYDRODYNAMICS MEDIATED FLUIDIC ASSEMBLY OF SILOCON RESISTORS, in the names of Mayer, et al.; and S. W. Lee et al. (S. W. Lee et al., “Electric-Field-Mediated Assembly of Silicon Islands Coated with Charged Molecules”,  Langmuir  2002, Vol. 18, pp. 3383-3386, January 2002), describe such methods.  FIG. 1E  illustrates a general example of this electrostatic approach. As is shown in  FIG. 1E , substrate  10  has binding sites  25  that are adapted with electrodes  27  that attract oppositely charged micro-components  55  suspended in fluid  29 . However, the use of electrostatically based fluidic micro-assembly can involve high cost associated with providing addressable electrode structures required for long range transport of micro-components by dielectrophoresis. 
     As noted above, many micro-assembled structures incorporate a variety of different types of micro-components. Thus, heterogeneous integration of more than one type of micro-component using such a massively parallel random placement process, such as fluidic micro-assembly, is highly desirable. What is needed therefore is a method for assembling micro-components into a micro-assembled structure on the massive scale enabled by random placement methods such as conventional fluidic assembly but with the precision and selective assembly capabilities of deterministic methods. 
     Modifications to at least one of the fluidic self-assembly methods described above have been proposed in an attempt to meet this need. For example, in one approach, conventional fluidic assembly techniques have evolved that use differently shaped micro-components that are adapted to engage differently shaped receptor sites on a substrate. This requires that the substrate has binding sites that are uniquely shaped to correspond to a shape of a particular type of micro-component. However, the constraints of surface etching techniques, micro-component formation techniques, cost, electrical function, and orientation limit the number of shape configurations that are available for use in discrimination, which in turn limits the number of different components that can be placed on the substrate using such a process. 
     In another approach, Bashir et al. discusses the use of binding between complementary DNA molecules or ligands to discriminate between binding sites. While this approach provides a high degree of differentiation high cost may be encountered in patterning the DNA or ligands on the substrate. (H. McNally et al., “Self-assembly of micro- and nano-scale particles using bio-inspired events”,  Applied Surface Science,  Vol. 214/1-4, pp. 109-119, 2003). 
     Thus, there is a need for a more cost effective method for the high volume heterogeneous assembly of micro-components. 
     SUMMARY OF THE INVENTION 
     In one aspect of the invention, a method is provided for assembling a structure on a support having a pattern of binding sites. In accordance with the method, a first fluid is provided on the surface of the support with the first fluid being of a type that that increases viscosity when cooled, the first fluid having first micro-components suspended therein each adapted to engage the binding sites. First fluid proximate to selected binding sites is cooled to increase the viscosity of the responsive fluid proximate to the selected binding sites so that the first micro-components suspended in the first fluid are inhibited from engaging the selected binding sites. 
     In another aspect of the invention, an apparatus is provided for assembling a micro-assembled structure on a support having binding sites thereon. The apparatus has a fluid source adapted to apply a first fluid having first micro-components therein onto the support, said first micro-components being adapted to engage the binding sites and said first fluid being of a type that increases viscosity when cooled; and a cooling applicator adapted to apply a cooled material to the support so that the support cools the first fluid to increase the viscosity of the first fluid proximate to the selected binding sites so that micro-components are inhibited from engaging the selected binding sites. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1E  illustrate various types of methods that are known in the prior art for fluidic self-assembly; 
         FIG. 2A  is a flow diagram of one embodiment of the method of invention; 
         FIG. 2B  is a flow diagram of another embodiment of the method of the invention for use in assembling several different types of micro-components; 
         FIG. 3A-3C  illustrate fluidic self-assembly in accordance with the method of  FIGS. 2A and 2B ; 
         FIGS. 4A and 4B  illustrate the assembly of a first type of micro-component to a support to form a first micro-assembled structure; 
         FIGS. 4C and 4D  illustrate the assembly of an intermediate type of micro-component to first micro-assembled structure to form an intermediate micro-assembled structure; 
         FIG. 4E  illustrates the assembly of a final type of micro-component to the intermediate micro-assembled structure to form a final micro assembled structure; 
         FIGS. 5A-5G  show embodiments of the invention, wherein a set of coolers are incorporated into a support proximate to selected binding sites; 
         FIGS. 5H-5J  show embodiments of the invention wherein a set of different coolers are incorporated into a support proximate to selected binding sites; 
         FIGS. 5K-5M  illustrate micro-assembly using another embodiment of a support having a set of different coolers; 
         FIGS. 6A-6D  illustrate various other embodiments of the invention wherein energy is selectively applied to cause localized cooling of a carrier fluid; 
         FIG. 7  shows an embodiment of an apparatus for assembling a micro-assembled structure in which portions of a support are selectively cooled and thereby cool a thermally responsive fluid having micro-components therein in order to permit selective assembly; 
         FIG. 8A  shows an embodiment of an apparatus for assembling a micro-assembled structure in which portions of a support are selectively cooled and thereby cool a thermally responsive fluid having micro-components therein in order to permit selective assembly; 
         FIG. 8B  shows an embodiment of a patterned cooler adapted to selectively cool a support; 
         FIG. 9  shows an embodiment of an apparatus for assembling a micro-assembled structure in which cooling can be applied selectively to support and thereby to a thermally responsive fluid having micro-components therein in order to permit selective assembly; 
         FIG. 10  shows an embodiment of an apparatus for assembling a micro-assembled structure in which cooling can be applied selectively to support and thereby to a thermally responsive fluid having micro-components therein in order to permit selective assembly; 
         FIGS. 11A-11H  provide illustrations depicting the application of one embodiment or method and apparatus of the invention in the assembly of a display; and 
         FIG. 12  illustrates the assembly of a first type of micro-component to a support to form a first micro-assembled structure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2A  is a flow diagram of one embodiment of the method of invention.  FIGS. 3A and 3B  illustrate one example of fluidic self-assembly in accordance with the method of  FIG. 2A . As is shown in  FIG. 3A , a support  60  is provided (step  105 ). Support  60  can be, but is not limited to, a flexible support such as polyethylene terephthalate, cellulose acetate, polyethylene, polycarbonate, polymethyl methacrylate, polyethylene napthalate, metal foils, cloth, fabric, woven fiber or wire meshes or rigid supports such as glass and silicon. 
     Support  60  has pattern of binding sites shown in  FIGS. 3A-3C  as binding sites  62 ,  64 ,  66 , and  68 . Each binding site  62 ,  64 ,  66 , and  68  is adapted so that a micro-component can be assembled thereon, such as by shaping binding sites  62 ,  64 ,  66 , and  68  to receive the micro-component. Alternatively, support  60  can have binding sites  62 ,  64 ,  66 , and  68  that are adapted to engage micro-components using, for example, shape matching, magnetic force, electrical force, hydrophobic attraction, hydrophilic attraction, molecular recognition, and/or capillary attraction as described in the prior art. 
     In operation, a thermally responsive fluid  72  is applied to support  60  (step  106 ). In the embodiments shown in FIGS.  2  and  3 A- 3 B, this is done by flowing a thermally responsive fluid  72  across support  60 . However, in other embodiments, thermally responsive fluid  72  can be applied to support  60  in other ways such as by immersing support  60  in a bath of thermally responsive fluid  72 . 
     As used herein, the term thermally responsive fluid is used to mean a fluid that increases its viscosity upon cooling. Examples of useful thermally responsive fluids include, but are not limited to, aqueous solutions of polymers, polyelectrolytes, polyampholytes (e.g. gelatin solutions), gums, polysaccharides (e.g. gellan, carregeenan, and agarose) or combinations thereof that increase viscosity upon cooling. The useful range of any of these thermally responsive fluids depends on factors that can include the gel transition temperature required and that, in turn, depends upon the concentration of polymer, ionic strength, type of ions, pH, and molecular weight of polymer and the distribution of charged groups of the polymer. For example, a useful thermally-responsive solution includes an aqueous gelatin solution between 1-20% gelatin for a gelatin molecular weight of 120K Daltons. 
     Still other examples of a thermally responsive fluid include aqueous solutions 0.1 wt % or higher of agarose, 0.4 wt % gellan or higher. The gel transition temperature of these solutions is approximately 15 C. 
     In still other embodiments, a thermally responsive fluid can comprise solutions of any polymer that interacts with a colloid to form a thermally responsive liquid that gels upon cooling. For example, the thermally responsive fluid can comprise a mixture of gelatin and, for example, colloidal silicas such as Ludox® sold by W. R. Grace &amp; Co., Davison Silica Products Division, East Chicago, Ill., U.S.A. 
     In yet another embodiment, a thermally responsive fluid can comprise an aqueous solution of xanthan gum with trivalent metal ions. For example, a gel transition temperature of between 25-75 C is achievable with 0.5 wt % xanthan combined with Aluminum ions as is described in A. B. Rodd et al., “Gel Point Studies For A Novel Biopolymer-crosslinker Gelling System”,  Proceedings of the  13 th    International Congress on Rheology ”, Cambridge, United Kingdom, Vol. 4, pp. 389, 2000. 
     The aqueous solutions described herein can include but are not limited to alcohols and polyethylene glycol. Non-aqueous solutions can also be used. For example, a thermally responsive fluid can be provided that incorporates chlorinated solvents and other non-aqueous solvents. 
     In application, thermally responsive fluid  72  is cooled in areas in and/or near selected binding sites on support  60 , shown in the embodiment  FIGS. 3A and 3B  as binding sites  62  and  66  (step  107 ). Thermally responsive fluid  72  is typically cooled in an indirect fashion.  FIGS. 3A-3C  illustrate an example of indirect cooling of thermally responsive fluid  72 . In the example shown in  FIG. 3A , a cooling material  90  is applied to support  60  in areas proximate to selected binding sites  62  and  66 . In response to the application of the cooling material  90 , support  60  is cooled in areas proximate to selected binding sites  62  and  66 . When thermally responsive fluid  72  comes into contact with cooled areas of support  60 , the viscosity of thermally responsive fluid  72  increases. This creates barrier zones  92  and  94  within thermally responsive fluid  72 . Barrier zones  92  and  94  have a viscosity that is higher than the viscosity of other areas of thermally responsive fluid  72 . Barrier zones  92  and  94  in certain embodiments can comprise fluid, gelatinous, or solid forms of first thermally responsive fluid  72 . Barrier zones  92  and  94  interfere with the ability of first type of micro-components  80  to engage binding sites  62  and  66 . 
     Accordingly, as is shown in  FIG. 3B , after barrier zones  92  and  94  have been formed at binding sites  62  and  66 , a first slurry  70  of a carrier fluid  73  and a first type of micro-components  80  are applied to support  60  (step  108 ). Carrier fluid  73  can comprise any fluid that can carry first type of micro-components  80  to support  60  and be usefully applied for fluidic self-assembly. In one embodiment, carrier fluid  73  comprises a thermally responsive fluid. In one embodiment, the step of applying a thermally responsive fluid (step  106 ), cooling the thermally responsive fluid to form barrier zones (step  107 ) and applying a first slurry (step  108 ) can be integrated such that the first slurry is applied by introducing first type of micro-components  80  into the thermally responsive fluid  72  already applied in step  106 . However, this is not necessary and carrier fluid  73  does not, in itself, have to comprise a thermally responsive fluid. This can be done where the barrier zones  92  and  94  formed in first thermally responsive fluid  72  will persist during application of carrier fluid  73 . 
     A first type of micro-components  80  can include, but are not limited to, integrated circuits on silicon, nanowires, beads, rods, cubes, disks, buckey balls, capsules, electrophoretic beads, LEDs, light emitting materials, light reflecting materials, light absorbing materials, conductive materials, magnetic materials, dielectric materials, aerogels, biological cells, DNA and DNA derivatives, and DNA templated structures. A first type of micro-components  80  can be sized within any range of sizes that can effectively be suspended in solution in the thermally responsive fluid. In this regard, in selected embodiments, first type of micro-components  80  can be sized as small as 1 nanometer, and as large as several millimeters. 
     The first type of micro-components  80  are adapted to engage binding sites  62 ,  64 ,  66 , and  68  as is known generally in the art described above. However, in the illustration of  FIGS. 3A-3C , it is not intended that the first type of micro-components  80  engage selected binding sites shown in this illustration as binding sites  62  and  66 . Accordingly, barrier zones  90  and  92  inhibit such engagement. Specifically, it will be appreciated that a first type of micro-components  80  typically follow a path of least resistance as they move about in carrier fluid  73 . Accordingly, where a first type of micro-components  80  encounter barrier zones  92  and  94  of higher viscosity, a first type of micro-components  80  will be deflected away from barrier zones  92  and  94  and therefore will not engage binding sites  62  and  66 . However, a first type of micro-components  80  are able to engage binding sites  64  and  68  which are not protected by barrier zones  92  and  94 . 
     After first type of micro-components  80  have been assembled to each of the non-selected binding sites  64  and  68 , first carrier fluid  73  and any non-engaged first type of micro-components  80  are removed from first micro-assembled structure  100  (step  109 ). This can be done by mechanical action, by vacuum, or by rinsing, for example. In one embodiment, a liquid such as thermally responsive fluid  72  is rinsed over support  60  to remove any of the first type of micro-components  80  that remain on support  60  and that are not bound to one of binding sites  62 ,  64 ,  66  or  68 . During removal of first slurry  70 , cooling material  90  remains in contact with support  60  proximate to the selected binding sites  62  and  66  so that barrier zones  92  and  94  remain in place to prevent any non-engaged first type of micro-components  80  of the first type from binding to the selected sites  62  and  66  during removal of first slurry  70 . The cooling material  90  can be removed from support to stop the cooling of support  60  proximate to binding sites  62  and  66  after removal of the first slurry  70  is complete (step  110 ). When cooling material  90  is removed from support  60 , the temperature of support  60  increases and barrier zones  92  and  94  that are created as a result of such local temperature decreases also dissipate. A first micro-assembled structure  100  is formed as a result of the union of the first type of micro-components  80  with support  60 . This first micro-assembled structure  100  can, in some embodiments such as the embodiment of  FIG. 2A , comprise a final micro-assembled structure  104 . 
     Additional micro-components can also be assembled to first micro-assembled structure  100 . FIGS.  2 B and  3 A- 3 C illustrate on embodiment of a method for assembling more than one micro-component to a support. The embodiment of  FIG. 2B  incorporates the method steps of  FIG. 2A  and adds additional steps  112 - 122 . In accordance with the method of  FIG. 2B , steps  105 - 110  are performed as described above. Then additional micro-components can be provided that are adapted to engage binding sites on support  60  in order to form an intermediate micro-assembled structure  102  or final micro-assembled structure  104  as described below. Such additional components can be the first type of micro-components  80  or, as shown in  FIG. 3C , a final type of micro-components  84 . 
     When it is determined that only one further assembly step is necessary to create a final micro-assembled structure  104  (step  112 ), a final slurry  76  of carrier fluid  73  having a final type of micro-component  84  is applied to first micro-assembled structure  100  (step  115 ). This enables a final type of micro-components  84  to engage binding sites  62  and  66  and thus form a final micro-assembled structure  104  as illustrated in  FIG. 3C . Carrier fluid  73  and any final micro-components  84  are removed to create a final micro-assembled structure  104 . Optionally, thermally responsive fluid  72  can be applied to first micro-assembled structure  100  (step  113 ), and first micro-assembled structure  100  can be selectively cooled by the application of cooling material  90  so that thermally responsive fluid  72  is cooled to form barrier zones (not shown). Such barrier zones can be used to leave select binding sites unoccupied. The cooling material  90  is removed so that the cooling applied in optional step  114  is then stopped (step  117 ). 
     When it is determined that more than two micro-assembly steps are to be performed (step  112 ), such as for example, where more than two different types of micro-components are to be joined to support  60 , additional steps  118 - 122 , shown in  FIG. 2B  are performed.  FIGS. 4A-4D  illustrate the operation of the method of  FIG. 2B  wherein these additional steps are performed. 
       FIGS. 4A and 4B  illustrate the assembly of a first type of micro-components  80  to a support  60  to form a first micro-assembled structure  100  in the same manner as is described above with reference to  FIGS. 3A-3B  (steps  105 - 110 ). As shown in  FIG. 4C , a thermally responsive fluid  72  is applied to micro-assembled structure  100  (step  118 ) and a cooling material  90  is applied support  60  to form at least one barrier zone  98  (step  119 ). As shown in  FIG. 4D , at least one intermediate slurry  74  comprising, a carrier fluid  73  and an intermediate type of micro-components  82  is then applied to support  60  (step  120 ). Further cooling materials  96  are also applied to cause thermally responsive fluid  72  of the intermediate slurry  74  to form at least one further barrier zone  98  proximate to, for example, binding site  62  (step  119 ). Because binding site  62  is insulated by barrier zone  98  and binding sites  66  and  68  are already engaged each with a first type of micro-component  80 , only binding site  66  is available for fluidic assembly with intermediate type of micro-components  82 . This forms an intermediate micro-assembled structure  102 . The intermediate slurry  84  is then removed from support  60  (step  121 ) and energy is then removed (step  122 ). The process then returns for more assemblies of intermediate micro-components or for assembly of final micro-components  84  (steps  113 - 117 ). 
     Steps  111 - 122  can be repeated as necessary to permit many cycles of micro-assembly to occur, each with an additional application of an intermediate slurry  74  of a carrier fluid  73  bearing intermediate type micro-components  82  to a previously formed micro-assembled structure. In any of these additional steps, support  60  or intermediate micro-assembled structure  102  can be cooled as necessary to form barrier zones. When it is determined that only one further assembly step is to be performed (step  112 ) steps  113 - 117  are performed to yield a final micro-assembled structure  104  as shown in  FIG. 4E . 
     As used herein, the first, intermediate, and final types of micro-components can comprise the same structures and can be different as necessary to permit formation of a heterogeneous micro-assembled structure. 
     Cooling of Support 
     The steps of cooling support  60  (steps  107 ,  114 , and  119 ) can be performed in a variety of ways. As noted above, the thermally responsive fluid  72  is cooled indirectly by applying a cooling material  90  to support  60  or to some component of support  60  so that support  60  cools thermally responsive fluid  72 . A cooling member  91  is typically used to perform this function, in various embodiments described herein. In particular, as will be described in greater detail below, cooling member  91  can comprise a pattern cooler or pattern roller that moves a cooled structure to apply a cooling material  90  to support  60 . In other embodiments cooling member  91  can comprise a source of a cooling material in the form of a fluid such as a liquid or a gas and a nozzle to controllably deliver the fluid cooling member  91  to support  60 . In still other embodiments cooling member  91  can comprise a control system for selectively electrical signals that actuate coolers in support  60 . 
     In certain embodiments, a cooling material  90  is broadly applied to support  60  using, for example, a cooling plate or other surface of cooling material  90  and support  60  is adapted to react this in a selective way, and to thereby selectively cool the thermally responsive fluid  72 . In other embodiments, cooling material  90  is selectively applied to selectively cool support  60  and to thereby selectively cool thermally responsive fluid  72 . 
       FIG. 5A-5G  show embodiments of the invention, wherein a support  60  is adapted with a set of coolers  132 ,  134 ,  136 , and/or  138  that are positioned in association with support  60  proximate to selected binding sites shown as binding sites  62 ,  64 ,  66 , and  68 . Coolers  132 ,  134 ,  136 , and  138  have different thermal response when cooled than the material forming support  60 . When a cooling material  90  is broadly applied to support  60 , coolers  132 ,  134 ,  136 , and  138  can, for example, be cooled to a greater extent than surrounding material  60 , or can be adapted to absorb energy from thermally responsive fluid  60  in an advantageous manner such as at a faster rate, or in a more localized manner than is possible by selectively cooling support  60 . 
     Coolers  132 ,  134 ,  136 , and  138  can comprise any of a variety of forms. In the example shown in  FIG. 5A , a cooling material  90  is applied to support  60  proximate to binding sites  62  and  66 , coolers  132  and  136  are cooled and, in turn, cool thermally responsive fluid  72  proximate to binding sites  62  and  66  to create barrier zones  92  and  94 . 
       FIG. 5B  shows another embodiment of a support  60  having an arrangement of coolers  132 ,  134 ,  136 , and  138 . In this embodiment, coolers  132 ,  134 ,  136 , and  138  are positioned around and proximate to binding sites  62 ,  64 ,  66 , and  68 . A cooling material  90  is shown to be selectively applied to support  60  proximate to coolers  132  and  136  in the manner described above with respect to  FIG. 4A  to achieve the formation of barrier zones  92  and  94 . 
       FIG. 5C  shows another embodiment of a support  60  having an arrangement of coolers  132 ,  134 ,  136 , and  138 . Specifically, in the embodiment shown in  FIG. 5C , each of binding sites  62 ,  64 ,  66 , and  68  have an associated cooler  132 ,  134 ,  136 , and  138  that is located in a portion of support  60  that is at a bottom most portion of binding sites  62 ,  64 ,  66 , and  68 . In this embodiment, when support  60  is cooled proximate to coolers  132 ,  134 ,  136  or  138  any thermally responsive fluid  72  in binding site  60 ,  62 ,  64 , and  66  is cooled. This increases the viscosity of the thermally responsive fluid  72  in the binding sites to form for example, barrier zones  92  and  94  that can interfere with the ability of a first type of micro-components  80  to be assembled to binding sites  62  and  66  respectively. 
       FIG. 5D  shows still another embodiment of a support  60  having an arrangement of coolers  132 ,  134 , and  136 . In this embodiment, support  60  has an arrangement of binding sites  62 ,  64 , and  66  each having a liquid  140  that is adapted to engage a liquid engagement surface  88  of a first type of micro-components  80 . Coolers  132 ,  134 , and  136  are positioned on support  60  proximate to binding sites  62 ,  64 , and  66 . When support  60  is cooled proximate to binding site  62  cooler  132  is cooled which, in turn, causes support  60  proximate to cooler  132  to cool fluid  140 . Fluid  140 , likewise, cools first thermally responsive fluid  72  to form a barrier zone  92  inhibits a first type of micro-components  80  from engaging liquid  140 . 
       FIG. 5E  shows another embodiment wherein support  60  has binding sites  62 ,  64 , and  66  each having a liquid  140  associated therewith to engage a liquid engagement surface  88  of a first type of micro-components  80 . As is shown in  FIG. 5E , in this embodiment, coolers  132 ,  134 , and  136  are positioned around and proximate to binding sites  62 ,  64 , and  66  in direct contact with binding sites  62 ,  64 , and  66  and directly cool liquid  140 . 
       FIG. 5F  shows still another embodiment wherein a support  60  is used having binding sites  62 ,  64 , and  66  each having a liquid  140  associated there with and provided to engage in liquid engagement surface  88  of a first type of micro-components  80 . As is shown in  FIG. 5F  coolers  132 ,  134 , and  136  are positioned at binding sites  62 ,  64 , and  66  respectively and are in direct contact with or immediately proximate to liquid  140 . In this embodiment, when any of coolers  132 ,  134 , and  136  are chilled, liquid  140  is cooled to form a barrier zone  92  as described above. 
     In any of  FIG. 5D ,  5 E or  5 F, the coolers can cool liquid  140  so that a barrier zone is formed based at least in part upon the cooling of liquid  140 . In still another embodiment shown in  FIG. 5G , deposits of liquid  141  operate as a cooler. This can be done by applying a pattern of liquid  141  prior to introduction of thermally responsive fluid  72 , with the liquid  141  being cooled, or super cooled, or that will react when applied to the support  60  or to thermally responsive fluid  72  in a manner that provides a cooling effect. In such an embodiment, fluid  141  can be used to comprise cooling material  90 . 
     It will be appreciated that cooling liquid  141 , such as acetone or methylene chloride, can be applied patternwise to the surface of a support  60 . 
     It will also be appreciated that cooling material  90  can similarly be applied to support  60  in a fluidic form such as a liquid or gaseous form. For example, a liquid cooling material  90  can be applied to support  60  uniformly or it can be applied in a pattern-wise fashion using among other things printing, drop on demand ink jet technology, masking, continuous ink jet technology, or printing technologies that use super critically cooled carbon dioxide as a solvent to deliver materials such as cooling material  90 . 
     Cooling material  90  can be applied to support  60  before thermally responsive fluid  72  is introduced and when applied in this fashion, cooling material  90  can be applied directly to a side of support  60  having binding sites on support  60  or cooling material  90  can be applied to an opposite side. Where cooling material  90  is applied to support  60  before introduction of thermally responsive fluid  72 , cooling material  90 , support  60  and or coolers such as coolers  132 , and  134  can be provided that ensure that any binding sites that are to be protected by a barrier zone will be cooled in a manner that does not allow the barrier zone to dissipate while a first slurry  70  having micro-components is applied to support  60 . Coolers  132  and  134  can be specially adapted for such a controlled cooling response. 
       FIGS. 5H-5L  show embodiments wherein support  60  is adapted with binding sites  62 ,  64 ,  66 , and  68  that are associated with coolers  132 ,  134 , and  136  that have a different thermal response to a uniform application of a cooling material to support  60 . 
     In  FIGS. 5H-5L , this difference is used to enable selective micro-assembly at selected binding sites  62 ,  64 ,  66 , and  68  on support  60 . In particular, this efficiency difference causes different ones of coolers  132 ,  134 , and  136  to attain the temperature for forming a barrier zone, while other ones of coolers  132 ,  134 , and  136  do not dissipate heat rapidly enough to attain an appropriate temperature for forming a barrier zone, in response to the application of the same energy. Controlling the characteristics of coolers  132 ,  134 , and  136  enables selecting which binding sites are filled and which form barrier zones to remain empty without specifically cooling some sites, such as by a scanning system or mask, as will be described in greater detail below, thereby allowing uniform energy delivery to all binding sites while providing discrimination. 
       FIGS. 5H-5J , illustrate how this can be done. In  FIGS. 5H-5J , coolers  134  have a different thermal response when cooled by the application of a cooling material  90  than coolers  132  and  136  have when exposed to the same amount of cooling.  FIG. 5H  depicts a first step of an assembly process having this arrangement of coolers  132 ,  134 , and  136  on a support  60 . As is shown in  FIG. 5H , a support  60  is uniformly cooled proximate to binding sites  62 ,  64 ,  66 , and  68  of support  60  either before or during exposure of support  60  to first slurry  70  of thermally responsive fluid  72  having first type of micro-components  80  therein. This cooling, which can be measured as the temporal rate of energy flow from an area of support  60 , is established so that less efficient coolers  132  and  136  form barrier zones  92  and  96  and so that the efficient coolers  134  also form barrier zones  94 . Accordingly, first type of micro-components  80  engage only binding sites  66  lacking coolers. 
       FIG. 5I  illustrates a second assembly step. In this assembly step, support  60  an exposure to a second cooling material  90  that is adequate for the more efficient coolers  134  to form a barrier zone  96  but that is inadequate for the less efficient coolers  132  and  136  to form barrier zones so that introduction of an intermediate slurry  74  having second or intermediate type of micro-components  82  therein allows the intermediate type of micro-components  82  to engage binding sites  62  and  68  that correspond to the less efficient coolers  132  and  136 . 
       FIG. 5J  illustrates yet another assembly step, such as a final assembly step. In this step, the exposure of support  60  to energy is too low to cause the more efficient coolers  134  to form barrier zones and allows a final slurry comprising final type of micro-component  84  in a carrier fluid final slurry  76  to attach to binding sites  64  corresponding to those more efficient coolers  134 . 
     It will be appreciated that, in certain embodiments of the invention, it is not necessary to introduce a second cooling material, and that in such embodiments, the flow of first slurry  70  will be timed to occur during a time when an initial amount of cooling sufficient to cause formation of barrier zones  92 ,  94 , and  98  at binding sites  62 ,  64 , and  66 , while the introduction of second intermediate slurry  74  can be timed to occur at a time after the cooling supplied by less efficient coolers  132  and  136  has diminished sufficiently to allow barrier zones  92  and  98  to dissipate, at the less efficient coolers  132  and before the cooling supplied by more efficient cooler  134  has diminished sufficiently to allow barrier zone  94  to dissipate. Similarly, in this embodiment, a final slurry can be introduced after the cooling supplied by more efficient cooler  134  has diminished sufficiently to allow barrier zone  94  to dissipate. 
     Discrimination can be conferred upon binding sites by making at least two types of coolers with differing thermal absorption characteristics or differing thermal release characteristics. 
       FIGS. 5K-5M  depict another embodiment of a support  60  having an arrangement of coolers  132 ,  134 ,  136 , and  138  that respond to the uniform cooling in different ways. In this embodiment, coolers  132 ,  134 , and  136  can be provided on support  60  that are formed from a common material having a common thermal response and a common thickness as applied to the support, but can still provide discrimination. This simplifies the production of the coolers and control of the location of their mounting to the support  60 . 
     Specifically, discrimination is accomplished in this embodiment by using an arrangement of coolers having different sizes to selectively control the thermal cooling that cooler  134  can provide as compared to coolers  132  and  136 . This limits the rate and/or amount of cooling that can be thermally provided to thermally responsive fluid  72  in a slurry to produce a barrier zone. The spatial distribution of area cooled by coolers  132 ,  134 , and  136  into cooler regions of the slurry determines the profile of reduced temperature areas surrounding each coolers  132 ,  134 , and  136 . Sufficient exposure cooling material  90  can cause a coolers  132 ,  134 , and  136  to produce a barrier beyond the lateral extent of cooler  132 ,  134 , and  136 . 
       FIGS. 5K-5M  show one embodiment of this arrangement of coolers  132 ,  134 , and  136 . In the embodiment shown in  FIGS. 5K-5M , coolers  132  and  136  are shown that cover substantially all of the bottom surfaces of binding sites  62  and  68 , while cooler  134  covers only a fraction of the lateral extent of coolers  132  and  136 . Binding site  66  has no coolers  134 . In a first step of an assembly process using support  60  shown in  FIG. 5L , a first uniform exposure of energy cooling material  90  is provided that is sufficient for smaller cooler  134  to produce a barrier zone  94  of adequate extent to protect its corresponding binding site  64  from attaching a first type micro-components  80  upon introduction of first slurry  70 , while the wider coolers  132  and  136  form barrier zones  92  and  96  to protect associated binding sites  62  and  68 , so that only binding site  66  with no cooler is filled with first micro-components  82 . 
       FIG. 5L  shows support  60  of  FIG. 5K  exposed to a second intermediate slurry  74  having a second type of micro-components  82  therein, with and exposed to a second, lower exposure to cooling material  90  that is adequate for the wider coolers  132  and  136  to form intermediate barrier zone  98 . However, the laterally smaller energy absorbing cooler  134  does not provide sufficient cooling to cause a barrier zone to form or may form a barrier zone that is too small to prevent adhesion of the intermediate type of micro-components  84  to binding site  64 , so each site associated with a laterally smaller coolers  134  can be filled by the intermediate type of micro-components  84  upon introduction of second intermediate slurry  74 . 
       FIG. 5M  shows the application of a final slurry  76  having final micro-components  84  applied to support  60 , while support  60  is not exposed to energy or is exposed to a level of energy (not shown) that is insufficient for any cooler to produce a barrier zone. This allows each binding sites  62  and  68  associated with the widest coolers  132  and  136  to receive final type of micro-components  86  upon introduction of final slurry  76 . 
       FIGS. 6A-6D  illustrate various other embodiments of the invention wherein energy as is selectively applied to cause localized cooling of a thermally responsive fluid  72 . As is shown in  FIG. 6A , a support  60  is provided having binding sites  62 ,  64 ,  66 , and  68 . In this embodiment, support  60  is cooled by applying a cooling material in solid form such as using a contact cooler  148  comprising a patterned cooling block  150  with projections  152  in contact with support  60  proximate to selected binding sites  62  and  66 . Projections  152  of patterned cooling block  150  selectively cool support  60  proximate to binding sites  62  and  66  to enable the formation of barrier zones  92  and  94  as described above. 
       FIG. 6B  illustrates the cooling of a selected binding site  62  using contact cooler  148  comprising a patterned cooling block  150  with projections  152  to cool a support  60  having binding sites  62 ,  64 , and  66  each associated with a liquid  140 . 
     It will be appreciated that such a contact cooler  148  can take many forms. For example, a cooling block  150  of the type shown in  FIGS. 6A and 6B  take the form of a platen, roll, or other cooled surface having projections  152  in the form of raised areas adapted to contact support  60  and to cool support  60  using a fixed pattern of projections  152 . 
       FIG. 6C  shows a different embodiment of a cooling block  150  having projections  152  in contact with support  60  and proximate to binding sites  62  and  66 . In this embodiment, projections  152  have selectively addressable actuators  154  that bring projections  152  into and out of contact with support  60  on demand. In this way, during multiple assembly cycles, support  60  can be cooled in a pattern that is dynamically adjusted without moving either cooling block  150  or support  60 . In the embodiment shown, projections  152  have selectively addressable actuators such as electrically actuatable micro-motors or piezoelectric actuators that can selectively bring projections  152  into or out of contact with support  60  on demand. 
       FIG. 6D  illustrates the cooling of selected sites using a cooling block  150  having projections  152 . In this embodiment, projections  152  are adapted to incorporate a selectively actuatable cooler  156  so as to permit dynamic adjustment of the pattern of cooled areas on support  60 . 
       FIG. 7  shows an embodiment of an apparatus  158  for assembling a structure in which cooling can be applied selectively to support  60  and thereby to a thermally responsive fluid  72  in order to allow the formation of barrier zones to permit selective assembly as described above.  FIG. 7  also shows using a web based continuous manufacturing process suitable for high-volume production. In this embodiment, a supply  160  provides a continuous web of support  60  having an arrangement of binding sites (not shown) thereon. The web of support  60  is passed across a first roller  162 . First roller  162  is a thermal transfer roller and capable of cooling selected areas of support  60  when in contact. In this regard, first roller  162  is adapted to be selectively cooled by a first pattern cooler  164  such as a Peltier type cooler or other source of cooling that can provide a desired pattern of chilled areas on first roller  162 . In operation, first pattern cooler  164  supplies energies of pattern of chilled areas  90   a  to first roller  162  as first roller  162  rotates. When web of support  60  engages first roller  162 , a corresponding pattern of cooled areas  90   b  is transferred from first roller  162  to web of support  60 . 
     After support  60  has been cooled, support  60  is passed through a first bath  165 . First bath  165  contains thermally responsive fluid  72 . As thermally responsive fluid  72  is cooled by support  60 , barrier zones are formed as described above. Support  60  with certain sites blocked by the barrier zones is passed through a first slurry bath  166 . Alternatively, support  60  can be cooled as it is passed through first bath  165  as described above. 
     First slurry bath  166  contains a first slurry  70  having micro-components, such as first type of micro-components  80 , within carrier fluid  73  such as thermally responsive fluid  72 . The barrier zones inhibit the first type of micro-components  80  from engaging selected binding sites. A first type of micro-components  80 , engage binding sites not protected by barrier zones to form a micro-assembled structure  100 . As support  60  continues to move through the system  158  shown in  FIG. 7 , support  60  passes through a rinsing device  168  that removes residual amounts of first slurry  70  from support  60 . 
     The web of support  60  then passes over at least one intermediate roller  170 . In the embodiment shown, intermediate roller  170  comprises another thermal transfer roller that is adapted to receive pattern of chilled areas  90   a  from an intermediate pattern cooler  172  and to selectively cool web of support  60 . After support  60  has been cooled support  60  is passed through an intermediate slurry bath  174 . Intermediate slurry bath  174  has a carrier fluid  73 , comprising in this embodiment, a thermally responsive fluid  72  containing intermediate type of micro-components  82 . Intermediate type of micro-components  84 , are then permitted engage binding sites on micro-assembled structure  100  to form an intermediate micro-assembled structure  102 . The type of thermally responsive fluid  72  used in the intermediate slurry bath  174  can be the same as or can be different than the type of thermally responsive fluid used in carrier fluid that is used in the first slurry bath  166 . 
     As thermally responsive fluid  72  cooled by support  60 , barrier zones are formed as described above. These barrier zones inhibit intermediate type of micro-components  84  from engaging selected binding sites. Intermediate type of micro-components  84  engage binding sites not protected by barrier zones to form a micro-assembled structure  100 . As support  60  continues to move through the system  158  shown in  FIG. 7 , support  60  passes through an intermediate rinsing device  176  that removes residual amounts of the first slurry from support  60 . 
     Web of support  60  then passes over final roller  180 . In the embodiment shown, final roller  180  comprises another thermal transfer roller that is adapted to receive pattern of chilled areas  90   a  from a final pattern cooler  182  and to selectively cool web of support  60 . After support  60  has been cooled by final roller  180 , web of support  60  is passed through a final slurry bath  184 . Final slurry bath  184  contains at least one final type of micro-components  86  within a carrier fluid  73  such as thermally responsive fluid  72 . It will be appreciated however that the thermally responsive fluid  72  can be used in the intermediate slurry bath  184  can be the same as or can be different than the carrier fluid that is used in the first slurry bath  166  or in the second intermediate slurry bath  174 . 
     As thermally responsive fluid  72  is cooled by support  60 , barrier zones are formed as described above. These barrier zones inhibit the final type of micro-components  86  from engaging selected binding sites. Intermediate type of micro-components  84 , engage binding sites not protected by barrier zones, to form a final micro-assembled structure  104 . As support  60  continues to move through the system  158  shown in  FIG. 7 , support  60  passes through a final rinsing device  186  that removes residual amounts of the first slurry from final micro-assembled structure  104 . Support  60  and final micro-assembled structure  104  then pass to a post-assembly processing station  220  wherein support  60  and final micro-assembled structure  104  are further processed for use, for example, by separating support  60  from final micro-assembled structure  104  or by otherwise packaging or processing final micro-assembled structure  104 . 
     It will be appreciated that once a pattern of energy is transferred to support  60 , “cool spots” are formed on support  60  that have a finite lifetime because they are heated by their surroundings. A cool spot is heated at a rate that depends primarily on the temperature difference between the cool spot and its surroundings including the thermally responsive fluid  72 . In order to prolong the lifetime of a hot spot, a thermally responsive fluid  72  may be advantageously supplied at a temperature slightly above a transition temperature at which the viscosity of the thermally responsive carrier fluid  72  undergoes meaningful change or transition of viscosity, such as a transition temperature at which thermally responsive carrier fluid  72  transitions from a liquid to a gel so as to minimize the amount of cooling required to form a barrier zone  92  while at the same time reducing the temperature difference between the chilled spot and its surroundings. 
     Another embodiment that selectively cools a support  60  to form barrier zones corresponding to selected binding sites on a support, is shown in  FIGS. 8A-8B . As is shown in  FIG. 8A , in this embodiment a continuous process is provided that does not include thermal transfer rollers  162 ,  170 , and  180 . Instead, in this embodiment, first pattern cooler  164 , intermediate pattern cooler  172 , and final pattern cooler  182  are adapted to directly cool support. As is also shown in  FIG. 8A , in this embodiment, intermediate pattern cooler  172  is shown directly cooling a support  60  so that a thermally responsive fluid  72  contained in intermediate slurry can form desired barrier zones. 
     Alternatively, any of the patterned coolers  164 ,  172 , or  182  can also comprise an array of electrically addressable cooling elements. For example, a typical array of electrically addressable cooling elements for use in the method of the present invention contains a plurality of adjacent, microscopic Peltier type cooling elements, which convert electrical energy via a joule effect into a cooling effect. Such thermal heads can be used in contact or, in close proximity with support  60  so as to transfer heat from support  60  to cool support  60  in a pattern-wise fashion as support  60  passes across a thermal transfer roller such as first roller  162 , intermediate roller  170 , or final roller  180 . 
       FIG. 8B  shows one embodiment of pattern cooler such as first pattern cooler  164  comprising a roller  191  that is adapted to directly cool support  60 . As is shown in  FIG. 8B , in this embodiment, roller  191  is adapted with a pattern of selectively addressable coolers  193   a  and  193   b  such as Peltier type cooling elements positioned near a surface  195  of roller  191 . Surface  155  of roller  191  contacts support  60  before or as support  60  passes through first fluid bath  165 . In the embodiment shown, coolers  193   a  are active and produce cool support  60  while coolers  193   b  are interactive and do not cool support  60 . Accordingly, as support  60  is passed into first fluid bath  165 , thermally responsive fluid  72  in first fluid bath  165  areas of support  60  that were cooled form barrier zones as described above, while in other areas, no barrier zones are formed. 
     In still other embodiments, any of pattern coolers  164 ,  172 , and  182  can be provided across a path of movement comprise a linear array cooler elements disposed across a pathway used by support  60  such as an array of Peltier type coolers, or another array of coolers. It will be appreciated that the methods described with respect FIGS.  7  and  8 A- 8 B can also be performed in a non-continuous process. For example, as is shown in  FIG. 9 , individual sheets of sections of support  60  can be provided on platen  190  that are passed through system  158  in a sequential or non-sequential process. Platens  190  can comprise any rigid or flexible structure that can hold and position a support  60  during micro-assembly. Platens  190  can be moved by a conveyor system or can be self-propelled and/or self-guiding. In the embodiment shown, energy is applied to support  60 , micro-assembled structure  100 , and at least one intermediate micro-assembled structure  102 , by way of a pattern cooler that directly cools the top surface of platen  192 ,  194 , and  196  respectively. 
     However, in another embodiment shown in  FIG. 10 , platens  190  can be adapted with a patterned contact cooler  206  that applies different amounts of cooling to support  60 , micro-assembled structure  100 , and at least one intermediate micro-assembled structure  102 , to cool a back surface of platen  198 ,  200  or  202  respectively which then cools thermally responsive fluid to form barrier zones as described above when exposed to a thermally responsive fluid to allow the formation of selected arrangements of barrier zones. 
     In another embodiment, individual sheets of support  60  can be passed through any of the above-described embodiments of an apparatus  158  for forming a micro-assembled structure without platens  190 . For example, the individual sheets can be passed through apparatus  158  using any known conveyor system including but not limited to a belt drum or other conveying system. 
       FIGS. 11A-11H  illustrate the application of one embodiment of an apparatus  158  for forming a color display having color display elements comprising, in this embodiment, a combination of red, green, and blue colored electrophoretic beads or bichromic beads.  FIG. 11A  illustrates the movement of a support  60  through micro assembly process while  FIG. 11B  illustrates a top down view of a section  212  of support  60  before the assembly of the support  60  and a first type of micro-component  80 , an intermediate type of micro-component  84 , and an intermediate type of micro-component  86 .  FIG. 11C  illustrates a top down view of a section  212  of support  60  after a first processing step. 
     Referring to  FIG. 11A , in a first step of the assembly process, support  60  is passed through a first fluid bath  165  containing a thermally responsive fluid. A pattern cooler (not shown) applies a pattern of energy proximate to each of the green micro-cup sites  216 , and blue micro-cup sites  218 . This causes the formation of a pattern of barrier zones  92  and  94  proximate to the green micro-cup sites  216  and blue micro cup sites  218  as seen on  FIG. 11C . 
     A first slurry bath  166  applies first slurry  70  of carrier fluid  73  having red micro-beads  230  to support  60 . When the first slurry bath  166  is applied, red micro-beads  230  bind to red micro-cup sites  214 .  FIG. 11D  shows a top view of a completed first micro-assembled structure  100  having an array of red micro-beads  230  filling each of red micro-cup sites  214 . 
     In this way a first micro-assembled structure  100  is formed. Micro-assembled structure  100  is then rinsed in a rinsing device  168  to remove any residual unbound red micro-beads  230 . The energy that allowed the formation of barrier zones  92  and  94  is then removed or allowed to dissipate so that other barrier zones can be subsequently applied to first micro-assembled structure  100 . 
     In the embodiment shown, after red micro-beads  230  are removed from first micro-assembled structure  100 , a new pattern of chilled areas formed on first micro-assembled structure  100  and first micro-assembled structure  100  is exposed in an intermediate slurry bath  174  having, in this embodiment, intermediate micro-components comprising green micro-beads  232  in a thermally responsive fluid  72  causing the formation of intermediate barrier zone  96  proximate to blue micro-cup sites  218  as is shown on  FIG. 11D . 
     Green micro-beads  232  are barred from engaging red micro-cup sites  214  because red micro-cup sites  214  are occupied by red micro-beads  230  and are also barred from engaging blue micro-cup sites  218  because blue micro-cup sites  218  are shielded by barrier zone  96 . Accordingly, as is shown in  FIGS. 11E-11G , while intermediate slurry  74  is applied to first micro-assembled structure  100  and barrier zone  96 , green micro-beads  232  engage green micro-cup sites  216  to form a pattern of green micro-beads on support  60  to yield an intermediate micro-assembled structure  102  shown in section  212  of  FIG. 11G . 
     As is also shown in  FIG. 11G , after assembly intermediate micro-assembled structure  102  is then rinsed by intermediate rinsing device  176  to remove any unbound green micro-beads  232 . During the rinse the intermediate barrier zone  96  are preserved so that unbound green micro-beads  232  do not engage blue micro-cup sites  218  during the rinse. The pattern of chilled areas formed on support  60  is removed or allowed to dissipate so that barrier zone  96  can to dissipate enabling binding sites blue micro-cup sites  218  to receive blue micro-beads  234 . 
     A final slurry bath  184  applies a final slurry  76 , having blue micro-beads  234  and a carrier fluid  73 , to intermediate micro-assembled structure  102 . Blue micro-beads  234  are blocked from engaging red micro-cup sites  214 , and green micro-cup sites  216  as they are occupied by, respectively, red micro-beads  230  and green micro-beads  232 . Accordingly, as is shown in  FIG. 11H , pattern of blue micro-beads  234  engage remaining unoccupied micro-cup sites, blue micro-cup sites  218  to form a pattern of blue micro-beads  234  on support  60  thus, a final micro-assembled structure  104  is formed. Final micro-assembled structure  104  is then rinsed to remove any residual unbound blue micro-beads  234  and then submitted for post-assembly processing station  220 , which can includes step such as drying, binding, laminating, or assembling final micro-assembled structure  104  well for use as an integrated display component. 
     In any embodiment of the invention, cooling of a thermally responsive fluid can be performed at any time before or during an assembly process and/or before or during a rinsing process so long as the cooling is performed under circumstances that will allow the formation of barrier zones while there is a meaningful risk that micro-components will be positioned to engage the binding sites. Thus, for example in the embodiment of  FIG. 12 , where a first slurry  70  is applied that has a carrier fluid  73  comprising a thermally responsive fluid  72  and first type of micro-components  80 , the step of applying a thermally responsive fluid to the provide support (step  105 ) can be omitted. This is because, in this embodiment, support  60  is selectively cooled (step  107 ) before first slurry  70  is applied (step  108 ). This allows barrier zones to form before there is a meaningful risk that first micro-components  80  will bind to the selected binding sites. In this way, steps  113  and  118  can also be integrated with steps  115  and  120  respectively, so as to shorten the intermediate assembly and final processes. 
     In various illustrations shown above, barrier zones  92 ,  94 , and  96  have been shown having shapes defined for illustrative purposes and these shapes are not limiting. It is sufficient that a barrier zone provide only the minimum resistance to the binding of micro-components to a selected binding site to inhibit such binding. For example, in certain embodiments, a partial blockage of a binding site can be sufficient. In another example, where ligands or other biological binding sites are used, it can be sufficient merely to block or mask the receptor sites of the ligand. 
     Further, in the embodiments illustrated above, barrier zones have been shown as being provided only for open binding sites that do not have micro-components bound thereto. This too is not limiting and the invention can be practiced in a manner that allows the formation of barrier zones proximate to binding sites that are occupied by micro-components. 
     This can be done, for example, to protect such micro-components from damage during subsequent assembly steps. 
     It will further be appreciated that the terms cool, cooling and selectively cooling as used in the present invention are relative measures of a temperature gradient that exists on the support  60 . In this regard areas that are described as being cooled in accordance with the method herein can be provided by applying heat other areas of the support, so that the selected areas for cooling will be cool relative to the elevated temperatures of other portions of the support. 
     The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
     PARTS LIST 
     
         
           10  substrate 
           21  binding sites in the form of recesses 
           22  binding site 
           23  binding site 
           24  binding site 
           25  binding site 
           27  electrodes 
           29  fluid 
           32  drops 
           34  liquid 
           36  surface 
           47  micro-components 
           48  hydrophobic surfaces 
           49  micro-components 
           51  micro-components 
           52  micro-component 
           53  magnetic surface 
           55  oppositely charged micro-components 
           60  support 
           62  binding site 
           64  binding site 
           66  binding site 
           68  binding site 
           70  first slurry 
           72  thermally responsive fluid 
           73  carrier fluid 
           74  intermediate slurry 
           76  final slurry 
           80  first type of micro-component(s) 
           82  intermediate type of micro-component(s) 
           84  intermediate type of micro-component(s) 
           86  final type of micro-component(s) 
           88  liquid engagement surface 
           90  cooling material 
           90   a  pattern of chilled areas 
           90   b  pattern of cooled areas 
           91  cooling member 
           92  barrier zone 
           94  barrier zone 
           96  barrier zone 
           98  barrier zone 
           100  micro-assembled structure 
           102  intermediate micro-assembled structure 
           104  final micro-assembled structure 
           105  provide support step 
           106  provide carrier fluid step 
           107  cool carrier fluid step 
           108  apply first slurry step 
           109  remove first slurry step 
           110  discontinue cooling step 
           111  further assembly determining step 
           112  last assembly determining step 
           113  apply thermally responsive fluid step 
           114  cool thermally responsive fluid step 
           115  applied final slurry step 
           116  remove thermally responsive fluid step 
           117  discontinue cooling step 
           118  apply thermally responsive fluid step 
           119  cool step 
           120  apply intermediate slurry step 
           121  remove intermediate slurry step 
           122  discontinue cooling step 
           132  cooler 
           134  cooler 
           136  cooler 
           138  cooler 
           140  liquid 
           141  liquid cooler 
           142  cooler 
           143  inductor 
           144  capacitor 
           145  inductor 
           146  cooler 
           147  capacitor 
           148  contact cooler 
           150  cooling block 
           152  projections 
           154  selectively addressable actuators 
           156  selectively actuatable cooler 
           158  apparatus for assembling a micro-assembled structure 
           160  supply 
           162  first roller 
           164  first pattern cooler 
           165  first bath containing thermally responsive carrier liquid 
           166  first slurry bath 
           168  rinsing device 
           170  intermediate roller 
           172  intermediate pattern cooler 
           173  intermediate fluid bath 
           174  intermediate slurry bath 
           176  intermediate rinsing device 
           180  final roller 
           182  final pattern cooler 
           183  final fluid bath 
           183   a, b, c  laser thermal printhead 
           184  final slurry bath 
           185   a, b, c  channels 
           186  final rinsing device 
           188  post-assembly processing station 
           190  platen(s) 
           191  roller 
           192  top surface of platen 
           139   a  cooler 
           139   b  cooler 
           194  top surface of platen 
           196  top surface of platen 
           198  back surface of platen 
           200  back surface of platen 
           202  back surface of platen 
           206  patterned contact cooler 
           210  micro-cup sites 
           212  section 
           214  red micro-cup sites 
           216  green micro-cup sites 
           218  blue micro-cup sites 
           220  post-assembly processing station 
           230  red micro-beads 
           232  green micro-beads 
           234  blue micro-beads