Abstract:
A processing method and apparatus uses at least one electric field applicator ( 34 ) biased to produce a spatial-temporal electric field to affect a processing medium ( 26 ), suspended nano-objects ( 28 ) or the substrate ( 30 ) in processing, interacting with the dipole properties of the medium ( 26 ) or particles to construct structure on the substrate ( 30 ). The apparatus may include a magnetic field, an acoustic field, an optical force, or other generation device. The processing may affect selective localized layers on the substrate ( 30 ) or may control orientation of particles in the layers, control movement of dielectrophoretic particles or media, or cause suspended particles of different properties to follow different paths in the processing medium ( 26 ). Depositing or modifying a layer on the substrate ( 30 ) may be carried out. Further, the processing medium ( 26 ) and electrical bias may be selected to prepare at least one layer on the substrate ( 30 ) for bonding the substrate ( 30 ) to a second substrate, or to deposit carbon nanotubes (CNTs) with a controlled orientation on the substrate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 13/823,690, filed May 8, 2013 and titled METHOD AND DEVICE FOR CONTROLLING PATTERN AND STRUCTURE FORMATION BY AN ELECTRIC FILED, which is a National Phase Application of International Application No. PCT/US12/49040 filed Jul. 31, 2012, which claims the benefit of and priority to prior filed Provisional Application Ser. No. 61/514,461 filed Aug. 2, 2011, and Provisional Application Ser. No. 61/664,690 filed Jun. 26, 2012, the disclosures of which are each expressly incorporated herein by reference in their entirety. This application is also related to commonly assigned International Application Serial No. PCT/US12/49056 entitled SYSTEM AND METHOD FOR TISSUE CONSTRUCTION USING AN ELECTRIC FIELD APPLICATOR filed Jul. 31, 2012 by the inventor hereof, hereby expressly incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to the formation of patterns or structures, particularly by film formation on substrates, utilizing nanometer to micron scale objects. More particularly the invention relates to such formation of patterns or structures by the manipulation of such objects and to the use of electric field applicators and to devices and methods utilizing electric field applicators to manipulate nano-to-micrometer scale objects. 
       BACKGROUND OF THE INVENTION 
       [0003]    Developments in nanotechnology, the manipulation of matter on the scale of 1 nm to 100 nm, have yielded materials and devices with applicability in medicine, electronics, and energy production, to name a few. Conventionally, there have been two approaches to continued developments in nanotechnology: bottom-up and top-down. Bottom-up approaches arrange nano-components into complex assemblies and have been useful in molecular assembly, atomic force microscopy, and DNA engineering. Top-down approaches create smaller devices by utilizing the influences of larger devices. For example, atomic layer deposition (“ALD”) is a process by which semiconductor elements are built at atomic-layer scales. 
         [0004]    To further capitalize on the benefits of nanotechnology, the ability to manipulate, activate, measure, characterize, and quantify nano-objects must be controlled with precision and at high-throughput. The human-like, individual interactions of the conventional bottom-up approaches are not suitably efficient for scaling up to mass production. 
         [0005]    However, sufficient control over nano-objects using top-down approaches must include electrodes of similar scale that are also configured to generate forces sufficient to manipulate the nano-objects. Due to the complexities of physics, geometrical factors, and the specificity needed for particular applications, electrode design and processing systems are not straight forward. Therefore, there remains a need to provide specific control in spatially enhancing and/or suppressing interactions between generated fields and nano-objects. Furthermore, it would be beneficial for semiconductor technology to merge with bioelectronics fabrication to develop novel approaches to the manipulation of nano-objects. 
         [0006]    In addition, in semiconductor processing, electric field control has been effective in manipulating the motion of ions or other charged particles, as disclosed in U.S. Pat. No. 7,867,409. Systems employing media or particles that only exhibit dielectrophoretic properties in the presence of electric fields are not well developed. Accordingly, there is a need to better control nano and other small objects in a processing medium during processing structures on substrates. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention overcomes the foregoing problems and other shortcomings and drawbacks of the known, conventional nano-object manipulation and control. While the present invention will be described in connection with certain embodiments, it will be understood that the present invention is not limited to these embodiments. To the contrary, this invention includes all alternatives, modifications, and equivalents as may be included within the scope of the present invention. These alternatives and modifications include, for example, extending the application novel nano-object manipulation and control solutions and their application to semiconductor technology to micro-object manipulation and control and to bioelectronic fabrication and other applications. 
         [0008]    In accordance with the present invention, the processing of a film upon a substrate or the other formation or modification of patterns or objects with the use of micro-or-nano size objects is enhanced by the application and control of temporally and spatially controlled electric fields. 
         [0009]    According to certain embodiments of the invention, a processing apparatus is provided having a processing chamber configured to receive a processing medium having dipole properties that are subject to being affected by an electric field while processing a substrate; and a substrate holder for holding a substrate to be processed within the chamber. The apparatus is provided with at least one electric field applicator that is operable to expose the substrate during processing to a spatial-temporal electric field that is capable of affecting the processing medium or the substrate when the electric field applicator is electrically energized by an electrical bias selected to interact with the dipole properties of the medium or particles therein. The electric field applicators may be addressable by a controller and may be interchangeable. A distribution coupling unit is provided that is operable to couple a time-varying electrical bias to the at least one electric field applicator to thereby energize the electric field applicator in a way that will affect the medium or the particles. A controller is provided to operate the apparatus to control temporal and spatial characteristics of the applied electric field to affect the processing medium to achieve a processing effect on the substrate. The processing medium may be a gas or a liquid. An electric field applicator may be located outside the processing chamber and transmit the electric field to the substrate, or be located inside the processing chamber, such as adjacent the substrate. The electric field processing apparatus may be of a size substantially equal to the size of the substrate or of a size smaller than the size of the substrate and configured to be scanned across the substrate. Where substantially equal to the size of the substrate, it may be a stationary part of the apparatus and activated and addressed by grid structure or other logic circuitry according to an appropriate spatial and time-domain algorithm. Where smaller, it may be controlled by some such algorithm as well as motion with respect to the substrate. 
         [0010]    According to certain embodiments of the invention, the electric field processing may include an irradiation source, such as, for example, a microwave radiation source, an ultraviolet radiation source, or an infrared radiation source. Further, the electrical bias may include a DC potential component, an AC or RF potential, a switched DC potential, another time varying waveform, or a combination thereof. The potential may be applied to the electric field by a distribution coupling unit through direct electrical contact, or by capacitive or inductive coupling. The apparatus may include a magnetic field generator, an acoustic field generator, or an optical force generation device to further influence the nano-objects. 
         [0011]    In certain embodiments of the processing apparatus, the processing medium and electrical bias may be configured for selective localized deposition of layers on the substrate. In a specific embodiment, the processing medium and electrical bias are configured for deposition of carbon nanotubes (CNTs) with a controlled orientation. The time-varying electrical bias in many embodiments varies at less than 10,000 Hz, and typically at less than 1,000 Hz. 
         [0012]    According to certain methods of the present invention, electric field processing of a substrate is carried out with a processing apparatus by supporting a substrate to be processed in a chamber, introducing a processing medium into the chamber which may also have particles carried by the medium, with the medium and particles possessing a dipole configuration when subjected to an appropriate electrical field. Then, a time-varying electrical bias is applied to at least one electric field applicator to create the electric field appropriate to affect the processing medium or particles therein in a desired way in the vicinity of or at the surface of the substrate. Then the substrate is processed with the affected processing medium and/or particles. The processing may include constructing one or more layers on the substrate, for example, or controlling the movement of suspended dielectrophoretic particles in the medium or onto the substrate, for example, particularly where the substrate is a semiconductor wafer and the process is etching material on the substrate or depositing a material onto the substrate. In some embodiments, the motion of suspended particles may be affected to cause suspended particles of different properties to follow different paths in the processing medium, which may be used to cause the suspended particles to be sorted. Further, the suspended particles may be bioagents, and the motion of suspended particles may be controlled in part by applying a static or time-varying electrical bias so as to deposit the suspended particles at predetermined locations on the substrate. 
         [0013]    In some embodiments, irradiating of the substrate may be carried out, for example, with microwave radiation, ultraviolet radiation, or infrared radiation sources. Depositing or modifying a layer on the substrate may also be carried out, such as with filament-assisted chemical vapor deposition (FACVD) or initiated chemical vapor deposition (iCVD). Further, the processing medium and electrical bias may be selected to prepare at least one layer on the substrate for bonding the substrate to a second substrate, or, may be selected to deposit carbon nanotubes (CNTs) with a controlled orientation, on the substrate. In some embodiments, the processing medium and electrical bias may be selected to affect the structure, or orientation, or both, of a first deposited layer on the substrate, and may do so differently for different layers on the substrate. 
         [0014]    These and other embodiments of the invention may be readily apparent from the following detailed description in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention. 
           [0016]      FIG. 1  is a schematic cross-sectional view of a processing chamber having an electric field applicator in accordance with one embodiment of the apparatus of the present invention. 
           [0017]      FIG. 2  is a diagrammatic view of a computer for use in controlling operation of the processing chamber of  FIG. 1  and in accordance with embodiments of the present invention. 
           [0018]      FIG. 2A  is a logic diagram of an embodiment circuitry for biasing the electric field applicator of the apparatus of  FIG. 1 . 
           [0019]      FIGS. 3A-3H  are diagrammatic views of exemplary electric field zones generated by the electric field applicator within the processing chamber of  FIG. 1 . 
           [0020]      FIGS. 4A-4B  are diagrams illustrating spatial bias functions of which the apparatus of the present invention is capable of producing. 
           [0021]      FIGS. 5A ,  5 B,  6 A,  6 B, and  7 - 9  illustrate grid members suitable for the grid member of the process chamber of  FIG. 1  and according to various embodiments of the present invention. 
           [0022]      FIG. 10  is a schematic cross-sectional view, similar to  FIG. 1 , of a processing chamber having an electric field applicator in accordance with another embodiment of the present invention. 
           [0023]      FIG. 11  is a schematic cross-sectional view of a processing chamber having an electric field applicator in accordance with one embodiment of the present invention. 
           [0024]      FIGS. 12A-12C  and  13 A- 13 B illustrate electrodes in periodic arrays in accordance with various embodiments of the present invention. 
           [0025]      FIG. 14  is a schematic illustration of groups of electrodes from  FIG. 13A  illustrated in a grid-like pattern for providing electric field zones as shown in  FIG. 3A . 
           [0026]      FIGS. 15A-15E  are schematic cross-sectional diagrams, similar to  FIGS. 1 and 10 , of depicting processing chambers having electric field applicators in accordance with alternative embodiments of the present invention. 
           [0027]      FIGS. 16A and 16B  are diagrams illustrating particle motion principles employed by the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    With reference now to the figures, and in particular to  FIG. 1 , a processing chamber  20  suitable for use with one or more embodiments of the present invention is shown and described in detail. The processing chamber  20  includes a chamber wall  22  enclosing a processing space  24 , which may be filled with a processing medium  26  including one or more fluids, solutes, and/or dispersants. Exemplary processing medium  26  may include atmospheric gas, reactive gas, low pressure vapor near vacuum, colloidal organic media, hydrogels, resin, organic solvent, water, alcohol, and so forth, and will be dependent on the particular application for which the processing chamber  20  is being used. The size of the processing space  24  is likewise dependent on the particular application and will vary accordingly; however, a processing space  24  having a volume ranging from about 0.1 L to several liters may be typical. 
         [0029]    One or more nanometer scale objects, which may include any atoms, biological, geological, organic or inorganic molecules, proteins, antibodies, targets, polymer blocks, or other similar materials having a width dimension ranging from less than 100 nm to 50 μm, that generally develop dipole properties, but are referred to, for convenience, as nano-objects  28 , may be suspended in the processing medium. Unlike charged particles, which can be caused to move by application of a uniform electric field, neutral dielectric objects will not similarly respond. Neutral dielectric particles suspended in or part of a medium will develop a dipole polarization when subjected to a uniform DC electric field, but the forces exerted on them will generally cancel. When the electric field is non-uniform, however, dielectrophoretic (DEP) motion occurs. On the other hand, as illustrated in  FIG. 16A , in a non-uniform electric field, where the medium is more polarizable than a particle suspended in it, the particle moves, relative to the medium, away from the stronger electric field (called negative dielectrophoresis (n-DEP). And as illustrated in  FIG. 16B , where the medium instead is less polarizable than the particle suspended in it, the particle moves, relative to the medium, toward the stronger electric field (called positive dielectrophoresis (p-DEP). 
         [0030]    The dielectrophoretic force imposed on a dipolar object is also affected by the frequency or time rate of change of the electric field. Different rates affect the object differently. Elongated objects are affected differently than spherical objects by the electric field, and can be affected by uniform fields, where spherical objects generally are not. Electric fields can also affect the interaction of liquids with solids, modifying hydrophobic and hydrophilic properties, which is a factor in electrowetting on dielectrics. To deal with the complex interactions that determine final motions of these dipolar objects in these electric fields, the EFA embodiments of the present invention provide well developed, flexible platforms that are sophisticated enough to control objects in the micron and sub-micron range onto substrates in the centimeter range with reasonable repeatability, speed, and large scale manufacturing capability. Techniques used for E-field manipulation of charged particles are inadequate for these purposes. 
         [0031]    A substrate  30  is supported on a substrate support  32  such that the substrate  30  is exposed to the processing space  24  and processing medium  26 . While not required, one exemplary substrate  30  may be  300  mm in diameter with a thickness of about 800 μm or prefabricated wafer with thinned area(s) across it. 
         [0032]    An electric field applicator (hereafter “EFA”  34 ) with associated bias connections  36  (also referred to as a distribution coupling unit), may be operatively coupled to the substrate  30 , such as being coupled to the chamber wall  22  of the processing chamber  20  proximate the substrate support  32 , in the substrate support  32 , or on the substrate  30 . The EFA  34 , along with the bias connections  36 , may be a permanent fixture coupled to the processing chamber  20  or releaseably coupled thereto for interchangeability for particular use and applications. The EFA  34 , along with the bias connections  36 , provide E-field control at the surface of the substrate  30 . By way of the bias connections  36 , an EFA  34  may be operatively coupled to a voltage generator  38  that is configured to generate an alternating current (AC) voltage having a selected waveform, or some other time-varying voltage that varies according to some selected bias algorithm. More voltage generators may be employed for applying more complex and sophisticated bias algorithms to the EFAs, for example, variable phase across different ones of the generators. 
         [0033]    In another embodiment, E-field is controlled by digitally formed bias at the electrode. Such approaches provide increased flexibility in creating and changing bias algorithms through programming tools. Different electric field algorithms may be required for different specific process applications. A typical practical range for electric field strength is from 7×10 3  V/m up to 2×10 5  V/m, though the range is not limited to these values. 
         [0034]    The processing chamber  20  of  FIG. 1  has the E-field control at the bottom of the processing chamber  20 .  FIG. 10 , as described below, depicts an alternative processing chamber  20 ′ having the E-field control at the top of the processing chamber  20 .  FIGS. 15A-15E  compare various modes of E-field control, including that for an alternative embodiment of the processing chamber  20 ′, which has the E-field control distributed at both the top and bottom of the chamber, shown in  FIGS. 15C-15E , or in other configurations in which multiple EFAs are used. Furthermore, EFAs configured for more or less permanent installation are provided with circuitry sufficiently sophisticated to individually bias different areas to produce field patterns described more fully below. On the other hand, externally mounted interchangeable EFAs can be in whole or in part hard wired to produce one or a limited number of patterns for the processing of a limited number of substrates, then exchanged with another EFA to produce field patterns suitable for processing another substrate. 
         [0035]    In some embodiments, and as shown in  FIG. 1 , the processing chamber  20  may further include a radiation source  40  configured to provide in situ irradiation and/or post-radiation to the processing medium  26  and/or substrate  30 . Additionally or alternatively, the substrate  30  may include an internal EFA  42  (shown in phantom) that is configured to be biased in a manner that is similar to the external EFA  34 . 
         [0036]    The EFA  34  (external as well as the internal) may, in typical embodiments, be generally planar, generally congruent to the size of the substrate  30 , and may be operable to a plurality of zones  44 , each zone  44  being an area in which the EFA  34  may generate a discrete force as compared to adjacent zones  44 . Two or more adjacent zones  44  having the same bias algorithm to create a spatio-temporal electric field (generating the same force effect) define a subgroup (referenced generally as groups  46  and illustrated as subgroups  46   a - 46   h  in  FIGS. 3A-3C ). In  FIG. 3A , all zones  44  have the same bias algorithm applied to form spatio-temporal distribution of the electric field, defining a single group  46   a.    FIG. 3B  includes four subgroups: a first subgroup  46   b  comprising “A” spatio-temporal distribution of the electric field, a second subgroup  46   c  comprising “B” spatio-temporal distribution of the electric field, a third subgroup  46   d  comprising “C” spatio-temporal distribution of the electric field, and a fourth subgroup  46   e  comprising no applied electric field. However, subgroups need not be homogeneous; in fact, in  FIG. 3C  a first heterogeneous subgroup  46   f  of 5×5 zones includes an alternating sequence of “A” spatio-temporal distribution of the electric fields and “B” spatio-temporal distribution of the electric fields while a second heterogeneous subgroup of 4×4 zones alternates between alternating rows of “A” and “C” spatio-temporal distribution of the electric fields and “A” and “B” spatio-temporal distribution of the electric fields. Still other subgroups  46   h  need not be limited to a particular grid-like area. For example, the E-field control of the apparatus of the present invention is capable of providing the spatial distributions illustrated in  FIGS. 3D-3H . As a result, a time dependent, macro-pattern  110   a,    110   b,    110   c,    110   d,    110   e,    110   f,  may be generated.  FIGS. 3D-3H  illustrate macro-patterns in accordance with various embodiments of the present invention and in which open pixels indicate no voltage potential, darkened pixels indicate a positive voltage potential, and shaded pixels indicate a negative voltage potential. The macro-pattern  110   a,    110   b,    110   c,    110   d,    110   e,    110   f  is operable to generate time-variant electric fields to manipulate cells according to a selected model by imposing a dielectrophoretic force. The cells accordingly move and align into an optimal position, bringing groups of cells into closer proximity, and resulting in faster agglomeration and adhesion to facilitate rapid growing of the tissue. 
         [0037]    To generate the appropriate zones  44  and to effectuate the particular movement of nano-objects  28 , one or more of the voltage generator  38 , bias connections  36 , EFA  34 , internal EFA  42 , and/or the radiation source  40  may be operatively coupled to a computer  48  that is configured to control operation thereof.  FIG. 2  illustrates one computer  48  that may be considered to represent any type of computer, computer system, computing system, server, disk array, or programmable device such as multi-user computers, single-user computers, handheld devices, networked devices, or embedded devices, etc., suitable for use in accordance with embodiments of the present invention. The computer  48  may be implemented with one or more networked computers  50  using one or more networks  52 , e.g., in a cluster or other distributed computing system through a network interface (illustrated as “NETWORK I/F”  54 ). The computer  48  will be referred to as “computer” for brevity&#39;s sake, although it should be appreciated that the term “computing system” may also include other suitable programmable electronic devices consistent with embodiments of the invention. 
         [0038]    The computer  48  typically includes at least one processing unit (illustrated as “CPU”  56 ) coupled to a memory  58  along with several different types of peripheral devices, e.g., a mass storage device  60  with one or more databases, an input/output interface (illustrated as “I/O I/F”  62 ), and the Network I/F  54 . The memory  58  may include dynamic random access memory (“DRAM”), static random access memory (“SRAM”), non-volatile random access memory (“NVRAM”), persistent memory, flash memory, at least one hard disk drive, and/or another digital storage medium. The mass storage device  60  is typically at least one hard disk drive and may be located externally to the computer  48 , such as in a separate enclosure or in one or more networked computers  50 , one or more networked storage devices (including, for example, a tape or optical drive), and/or one or more other networked devices (including, for example, a server  64  as illustrated herein). 
         [0039]    The CPU  56  may be, in various embodiments, a single-thread, multi-threaded, multi-core, and/or multi-element processing unit (not shown) as is well known in the art. In alternative embodiments, the computer  48  may include a plurality of processing units that may include single-thread processing units, multi-threaded processing units, multi-core processing units, multi-element processing units, and/or combinations thereof as is well known in the art. Similarly, the memory  58  may include one or more levels of data, instruction, and/or combination caches, with caches serving the individual processing unit or multiple processing units (not shown) as is well known in the art. 
         [0040]    The memory  58  of the computer  48  may include one or more applications (illustrated as “PROGRAM CODE”  66 ), or other software program, which are configured to execute in combination with the Operating System  68  and automatically perform tasks necessary for controlling the voltage generator  38 , the bias connections  36 , and/or the radiation source  40 , with or without accessing further information or data from the database(s) of the mass storage device  60 . 
         [0041]    Those skilled in the art will recognize that the environment illustrated in  FIG. 2  is not intended to limit the present invention. Indeed, those skilled in the art will recognize that other alternative hardware and/or software environments may be used without departing from the scope of the present invention. 
         [0042]    Using the computer  48 , the EFA  34  may be operated so as to provide a spatio-temporal distribution of the electric field over one or more zones  44  or subgroups  46  as desired. In that regard, the EFA  34  may comprise at least one grid member  70 , a first embodiment of which is shown in  FIG. 4A  and includes a plurality of electrodes  72  arranged in a parallel array. Each electrode  72  may have a cross-sectional dimension ranging from about 0.1 mm 2  to about 1 mm 2  and is separated from an adjacent electrode  72  by distance that ranges from about 1 mm to about 50 mm. While the inter-electrode spacing of the grid member  70  as shown is constant, it would be readily appreciated that uneven spacing may also be used. The grid member  70  may be biased, as a whole, or subgroups thereof, by an output voltage from the voltage generator  38  (for example, 100 V peak-to-peak), at a particular phase offset and timing and in accordance with a selected waveform. The waveform may be generated by a function generator (not shown) or the computer  48  and, if necessary, the output voltage may be stepped using a transformer (not shown). 
         [0043]    The applied voltage produces attractive or repulsive forces when electric field interacts with nano-objects in the form of a traveling wave on the surface of the substrate  30 . Nano-objects  28  within the processing medium  26  and proximate the surface of the substrate  30  are influenced by the traveling wave and respond (e.g., align and/or travel) according to one or more electrokinetics principles, such as electrophoresis or dielectrophoresis. According to electrokinetics principles, a force (or torque) applied to the nano-object  28  is induced by the interaction of an induced dipole (due to polarization of the dielectric nano-object  28 ) with the imposed time-varying electric fields. When the electric field is uniform, an induced Coulombic attraction between accumulated charge of the nano-object  28  and the grid member  70  is cancelled (assuming symmetric distribution of the charge at a spherical nano-object) and the net force on the nano-object is zero. When the electric field is non-uniform, a resultant net force (i.e., non-zero) is induced and causes the nano-object  28  to undergo motion in dependence on the electric field configuration (translational motion, rotation, attraction, etc.). This latter effect occurs with AC or pulsed DC bias potentials and is known as dielectrophoresis, which is dependent on the applied frequency (ranging from about 100 Hz to about 100 MHz, more commonly in the 1 kHz to 10 kHz range). For nano-objects  28  that are in solution and have maximum width dimensions that are greater than 1 μm, dielectrophoretic behavior may be described by the Clausius-Mossotti factor model; nano-objects  28  in solution and having a maximum width dimension that is less than 1 μm exhibit greater surface charge effects such that an electrical double layer occurs and the nano-object&#39;motion is more complex, due to the electric double layer and electro-osmotic transport. 
         [0044]    By appropriately phasing the voltage potential of successive electrodes  72 , for instance, in accordance with Equation 1, the traveling wave may be generated by in-phase and out-of-phase interferences and is effective to induce movement (rotational and/or translational) of the nano-objects  28 . 
         [0000]        V   i   =V   0 sin (ω i   t+iΔφ )  (1)
 
         [0045]      FIG. 4B  illustrates a grid member  74  in accordance with another embodiment of the present invention that includes the electrodes  72  of  FIG. 4A  and a second plurality of electrodes  76 , the electrodes  76  of the second plurality being aligned in a parallel array relative to itself and angularly oriented with respect to the first plurality of electrodes  72 . The first plurality of electrodes  72  may be phase shifted in accordance with Equation 1 while the second plurality of electrodes  76  may be shifted in accordance with Equation 2. 
         [0000]        V   j   =V   0 sin (ω j   t+jΔφ )  (2)
 
         [0046]    While the electrodes  72 ,  76  are shown to be generally orthogonal, the angular displacement between the first and second electrodes  72 ,  76  need not be so limited. Yet, the particular illustrative arrangement may provide a focusing effect when aligning or assembling nano-objects  28  into a point, a line, or other geometric design. 
         [0047]    Grid members  78 ,  80 , shown in  FIGS. 5A and 5B  respectively, are similar to the grid members  70 ,  74  of  FIGS. 4A and 4B  but further include an areal electrode  82  that is separated from other electrodes  72 ,  76  by a properly insulating layer (not shown). When an alternating or pulsing voltage potential is applied to the areal electrode  82 , with or without phase shifted voltage potentials applied to the first and/or second electrodes  72 ,  76 , the resultant electric field may provide agitating or mixing force configured to stir the nano-objects  28  within the processing medium  26 . The areal electrode  82  may also be used in a manner to provide specific transport of the nano-objects  28  at the surface of the substrate  30 . 
         [0048]    Electrodes of a grid member comprising the EFA  34  need not be linear nor arranged into arrays. For example, in other embodiments of the present invention, the electrodes  84  may be oriented in a concentric-shaped grid member  88  as shown in  FIG. 6A  or electrodes  86  may be oriented in an axial or arcuate-shaped grid member  90  as shown in  FIG. 6B . The concentric and axial electrodes  84 ,  86  may be used separately or in conjunction with other electrodes  72 ,  74 ,  82 , including those described herein and may, in fact, be biased in accordance with Equation 1. 
         [0049]    Still other grid members  92 ,  94  may include one or more interdigitated, planar electrodes  96 ,  98  as shown in  FIG. 7  and in which the fingers  100 ,  102  of the electrodes  96 ,  98  are off-set and insulated to avoid electrical crossing. Electrodes  104 ,  106 ,  108 ,  110  of the grid member  94  shown in  FIG. 8  are intertwining and again may be appropriately insulated. 
         [0050]      FIG. 9  illustrates another grid member  112  in accordance with still another embodiment of the present invention. The grid member  112  includes an areal electrode  114  with a plurality of openings  116  extending therethrough and in vertical alignment (i.e., interdigitated) with a corresponding plurality of post electrodes  118 . Depending on the polarization ratio between the processing medium and the nano-object, this configuration will support increased densification of the nano-objects above the post electrodes  118 , and slightly between them in the case of positive dipoles (DP). In the case of negative DPs, the depleted nano-object areas will be just above the post electrodes  118 . The nano-objects will be forced into suspended positions above the substrate and will facilitate the forming of a specific structure. The actual effect will depend on geometrical relations in grid member  112 . Implementing stabilization of such pre-structured nano-object distribution by proper radiation in specific media will generate a structurally or geometrically patterned chain structure on the surface of the substrate. 
         [0051]    One of ordinary skill in the art with the benefit of the teachings herein would readily appreciate that the processing chamber need not be limited to the configuration shown in  FIG. 1 . In that regard, and as shown in  FIG. 10 , a processing chamber  20 ′ in accordance with another embodiment of the present invention having particular applicability to thick substrates (for example, substrates  30  having a thickness greater than about 1 mm). The processing chamber  20 ′ is similar to the processing chamber of  FIG. 1  (like reference numerals referring to similar parts); however, the EFA  34  is positioned above the substrate  30  so as to apply the electric field from above the substrate  30 .  FIG. 15A  shows the E-field control of the processing chamber  20  of  FIG. 1  having a single or similarly configured EFAs at the bottom of the chamber, while  FIG. 15B  shows the E-field control of the processing chamber  20 ′ of  FIG. 10  having a single or similarly configured EFAs at the top of the chamber. Although not specifically shown herein, other processing chambers may be envisaged that incorporate the top and bottom approaches to the electric field applicator. 
         [0052]      FIGS. 15A and 15B  illustrate ways of controlling E-fields at the surface of a substrate with a single planar bias applied, showing the EFAs arranged as in the processing chamber of  FIG. 1 , at the bottom of the chamber, and  FIG. 10 , at the top of the chamber.  FIGS. 15C-15E  illustrate ways of controlling E-fields using multiple EFAs, preferably located at different levels or in different planes; those illustrated being depicted at the top and the bottom of the processing chamber  20 ′. 
         [0053]      FIG. 11  illustrates a processing chamber  120  in accordance with yet another embodiment of the present invention having a chamber wall  122  enclosing a processing space  124  containing a processing medium  126  with one or more nano-objects  28  therein. A substrate  128  is supported within the processing space  124  and exposed to the processing medium  126 . The electrical field applicator  130  that is specifically shown herein includes a plurality of periodically arranged electrodes  132  with associated bias connections  134 , is configured to generate an alternating current having a selected waveform, and may be operated in a manner similar to the processing chamber  20  of  FIG. 1 . The electrodes  132 , having a selected geometric shape, are spaced in the y-axis direction in a periodic nature such that the distance between adjacent electrode members along the y-axis, 2d ty , ranges from about 50 μm to about 1 mm. 
         [0054]    The shape and size of the electrodes may vary, a few examples of which are shown in  FIGS. 12A-12C .  FIG. 12A  illustrates electrodes  134   a,    134   b  having a stem  136  and a circular portion  138   a,    138   b  of which the radius may be selected and for which the radius, R 1 , of electrodes  134   a  is greater than the radius, R 2 , of electrodes  134   b  and adjacent ones of the electrodes  134   a,    134   b  are spaced with a periodicity, 2d ty , which may range from 50 μm to about 1 mm interelectrode distance.  FIG. 12B  illustrates pyramidal electrodes  140   a,    140   b,  again spaced with selected periodicity,  2 d ty , but with a base length varying such that the electrode  140   a  has a base length, B 1 , greater than the base length, B 2 , of the electrode  140   b.    
         [0055]    Yet another example, electrodes  142   a,    142   b  may vary in concavity, such as C 1  and C 2  shown in  FIG. 12C . The shape, size, and periodicity of the electrode may be selected on desired movement of the nano-objects  28  and the in-plane resolution of the zones  44  and thus should not be limited to the particular shapes, sizes, and configurations as shown herein. 
         [0056]    Furthermore, and regardless of the particular electrode shape and size selected, the electrodes  134   a  may also be arranged linearly in the y-axis direction, as shown in  FIG. 13A , or may also be offset in the x-axis direction, as shown in  FIG. 13B . By off-setting the electrodes  134   a,  one or more groups of the electrodes  134   a  may be arranged, such as is shown in  FIG. 14 , each group being separately biased in a manner similar to the electrodes  72 ,  76  ( FIG. 4B ) above, so as to define the zones  44  ( FIG. 3A ) with a selected spatial resolution. 
         [0057]    While the term “nano-objects” has been defined more broadly above to apply to multi-micron sized objects, object size smaller than 100 nm is suitable for most semiconductor applications of the invention. Semiconductor applications of the invention include, for example, cleaning a wafer, e.g., to locally force flow of a liquid or other fluid in a cleaning process. Another semiconductor application of the invention is applying fluid agitation, for example, ultrasonic agitation, to a cleaning fluid or other medium. The nano-objects may, in such cases, be the molecules of such fluids. Further, a time varying change in a field gradient may be applied to move particles (considered as “nano-objects”) from the semiconductor substrate into the fluid. 
         [0058]    In general, as explained above, the time-varying change in electric field can be AC. Where DC is applied, at least temporarily, particles tend to move toward an electrode or one of the areas of a given potential bias. In general, where the particles are more polarizable than the medium, they move toward the higher E-field, but where the medium is more polarizable than the particle, the particles move toward the weaker E-field. With AC, for example, simple sinusoidal AC, particles can be made to collect between such electrodes. The time varying function to use for various purposes depends on the physical and electrical properties of the particle or nano-object, as well as to the properties of the medium (the viscosity or electrical properties of the medium, for example). In various plasma assisted coating or etching processes in semiconductor manufacture, the present invention is useful for controlling charged particles, such as by moving ions to the surface of a substrate, etc. The concept can be used in deposition to change deposition rates in local areas of a semiconductor substrate. In structures with areas of high electric field concentrations, such as around corners or features of varying geometry or conductivity, the invention can be used to even out the electric field on the substrate. 
         [0059]    Further applications of the invention to semiconductor manufacture include “self-assembly” and surface preparation for grid structure, moving polymers into a lower energy state, changing critical dimensions, electrically charging during etching, etc. 
         [0060]    The invention can be used to transport particles in a highly viscous fluid, such as a hydrogel, which can be highly viscous. For example, it can be used to first move one type of particle, then different types of particles, selecting the voltage and timing or special configuration of the areas to facilitate particle selection. Or, it can be used to affect motion of a fluid, or to manipulate a medium. Primarily, selective motion of different particles or media can be done sequentially, but it can be done simultaneously by application of different signals, although this would make the apparatus and its control more complex. There can be more than one grid or one grid with more than one field pattern applied. The time varying factor can be in the form of DC switching, on and off, at, for example, 100s or 1000s of Hz, as well as a continuous waveform. 
         [0061]    The circuits needed to apply potential to a grid are known technology. Several of the known schemes used to energize pixels on a display may be used to apply potentials to the areas. For example, the electrodes of the EFA  34  may be selectively operable to define a plurality of zones  44  by circuitry  49  as diagrammatically illustrated in  FIG. 2A . The circuitry  49  may include a programmable controller, which may be in the form of a computer  48 . Each zone  44  may be an individual electrode or an area influenced by several electrodes in which a discrete force may be applied to a particle and/or the medium. If desired, two or more adjacent zones  44  having the same (homogeneous) or different (heterogeneous) electric fields may define a subgroup that is operable to generate a selected force onto the particles. By specifying the function to be achieved, an electrical design engineer would be able to provide the appropriate logic. Therefore such control schemes are not described here in detail. 
         [0062]    Other structural details and alternatives to the processing apparatus of this invention and other applications of the general concepts set forth herein are set forth in the related and commonly assigned International Application Serial No. PCT/US2012/049056 (Attorney Docket No. TDCT-034WO) entitled SYSTEM AND METHOD FOR TISSUE CONSTRUCTION USING AN ELECTRIC FIELD APPLICATOR filed on even date herewith by the inventor hereof, hereby expressly incorporated herein by reference. This international application describes use of the present invention in the construction of tissue in which individual cells in the range of 1 to 10 microns in size, or clusters of cells that make up the particles or objects of interest in the 50-100 micron size range. 
         [0063]    The temporal or time-varying factor refers to changes of a short term nature. For example, while layers of cells are processed with grids changed from layer to layer or within a layer, it is during the application of a layer in which potentials are temporally varied to move or orient cells or cell clusters, or to control charge build up in one layer during its construction and before going to another layer. In tissue construction, for example, field strength must be limited to prevent damage to the tissue. 
         [0064]    While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.