Abstract:
A method of providing connectivity to a microsized device, the method includes the steps of providing an ablative base material having at least a top surface; providing a die having a first and second surface and having bonding pads at least upon the first surface; placing the die with the at least first surface of the die contacting the at least first surface of the ablative base material; and ablating a channel in the ablative material proximate to the die.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to the field of microsized devices and in particular to processes providing connections to microsized devices, including processes based on the use of ablative films to connect a plurality of microsized devices to one another. More specifically, the invention relates to ablative means for providing fluidic, electrical, photonic, magnetic, and mechanical connections to microsized devices. 
     BACKGROUND OF THE INVENTION 
     Microsized devices include, for example, micro-accelerometers and micro-gyroscopes for detecting linear and angular accelerations as manufactured by Analog Devices, Inc., chemically sensitive field effect transistors, used to detect the presence of certain molecular vapors such as carbon monoxide or ethanol, pressure sensors for measurement of pressures in automotive systems or micro phonic sensors, such as those employed in cell phones to detect and reproduce audio sounds, and optical sensors for detecting the presence of objects by infra-red radiation. These and other microsized devices are well known to practitioners of micro systems technology (MST). Also well known in that art are the difficulties encountered in inexpensive packaging of such microsized devices, in part because their small sizes require accurate positioning of connections and also because the connections may be of many different types, for example electrical, mechanical, or fluidic (vapor). Because the objects are small, many interconnected devices may be incorporated for systems applications. Additionally, since the devices are small, connections must be made so as not to perturb their functionality, for example by mechanical stress, especially in the face of changes in external environment in which collections of devices are operated, such as temperature or humidity. 
     Previous means employed for the connection of microdevices have included the use of automated wire bonding apparatus, use of ball grid arrays technology, fabrication of special packages using materials having temperature matched expansion coefficients, and the use of packages encapsulating devices in inert or chemically controlled atmospheres. Although these techniques offer sophisticated solutions, their implementation is not without expense, as is well known, for example, in the case of the packaging of micromirror devices (MMD) as manufactured by Texas Instruments, Inc. More recently, lower cost solutions have become available for mounting and connecting arrays of microsized devices on polymer films, for example those using films on which are patterned conductive lines, which may be deposited by many techniques, including ink jet printing of fluids. Such fluids may be conductive as deposited or may become conductive upon subsequent processing, for example by thermal annealing. These films are typically flexible and therefore are less likely to perturb the functionality of the microsized devices by mechanical stress. 
     One means of depositing conductive lines, related to the present invention, is by depositing conductive fluids to fill channels made in polymer films, for example channels made by laser ablation of polymer films, hereinafter referred to as ablative films. As is well known in the art of MST, microsized devices may then be placed proximate to the conductive lines; and connections, typically electrical, may be made using a variety of techniques, including wire-bonding, flip chip bonding, electroplating, and deposition of conductive materials, including deposition of conductive fluids by inkjet means, typically to ensure the reliable connection of electric leads to the devices or “die.” 
     Referring to  FIG. 1   a , there is shown a cross-section of a prior art ablative film  5 . The ablative film  5  includes a substrate  10 , typically a flexible polymer such as a polyamide or polycarbonate, and one or more energy-absorbing layers  20  which can be removed, all or in part, by exposure to intense radiation, or in other words, can be ablated, for example by radiation from a near IR laser. Ablative film compositions which can be removed by radiation from a near IR laser are disclosed, for example, by M. Zaki Ali, et al. in US Patent Publication 2005/0227182, which further contemplates using the ablative films, once ablated, as photolithographic masks for subsequent image wise ultraviolet exposure of flexography materials. The ablative films described in US 2005/0227182 may contain additional layers which serve purposes other than of a substrate or of energy absorbing layers, for example release layers used in lamination and surface energy control layers for repelling liquids, so that the ablative films, once ablated, may serve a variety of purposes. Many other material types of polymeric ablative films and laser ablation processes are well known in the art of laser ablation and laser processing for the manufacture of patterns and structures. For example, U.S. Pat. No. 7,115,514 by Richard Stoltz and assigned to Raydiance, Inc., describes a laser ablation process using short pulses at wavelengths shorter than the near IR are described for ablating a wide variety of materials including metals and inorganic materials and for altering their surfaces by ablation. 
     Referring to  FIG. 1   b , there is shown a cross-section of another prior art ablative film  5  of a more complex structure. The ablative film  5  includes a substrate  10 , and multiple layers  30 , some of which are energy absorbing layers. These layers can be removed, all or in part, by exposure to intense radiation. Other layers may provide desired colors or surface properties, such as hydrophobicity, or may comprise release layers to allow separation of the layers, and may be removed (ablated) when nearby underlying or overlying energy absorbing layers absorb radiation. 
     Referring to  FIGS. 2   a - 2   b , there is illustrated in cross-section and top-view, respectively, prior art formation of a channel  40  in an ablative film  5  of  FIG. 1   a . The ablative film  5  includes the two energy-absorbing layers  20  and the substrate  10  as described above. The base  50  of the channel  40  may be altered by the ablation process, for example its surface may be rendered hydrophilic. 
     Among the many known uses for ablative films, subsequent to patterning by ablation, are those relying on the geometry and surface properties of the ablated film to confine deposited fluids, such as fluids containing conductive materials such as metallic particulates. These fluids are typically deposited by well-known techniques such as ink-jetting or immersion in fluid baths followed by removal, for example by mechanical wiping blades, of excess fluid not in the ablative channels. Referring to  FIG. 2   c , there is illustrated in cross-section a prior art process for forming an electrically conductive material  60  in an ablated channel  40  in the ablative film  5 . For example, the conductor  60  may be formed by jetting (preferably by inkjet printing means) a liquid containing a metallic precursor into the channel  40  and then annealing the liquid to form the conductor  60 . The conductor  60 , as commercialized, for example by Dimatix, Inc. and Cabot Corporation. 
     The deposition of conductors in channels formed in polymeric films has further been employed to connect together microsized devices electrically, for example by positioning microsized devices on the top surface of polymer films having conductors patterned in channels or on the film surface, the positioning means being one of mechanical placement or, alternatively self assembly, as practiced by Alien Technologies, Inc. The microsized devices are positioned in an approximate way near the conductors and then one or more conductive metal strips are deposited which extend from the microsized device(s) to the conductor(s) to establish electrical connections. Methods of self-aligned positioning include alignment by matching geometrical features built into both the microsized devices and the substrate or the use of chemical constituents deposited pattern wise on the substrate which attract matching chemical constituents applied to the microsized devices as referenced in Sharma, et al., US Patent Publication 2006/0134799 and Sharma, et al., US Patent Publication 2006/0057293. For example, optically emitting diodes arrays may be so formed for display applications. 
     Although such prior art techniques can provide useable arrays of interconnected devices, the process of placement of the microsized devices must be sufficiently accurate to allow for the cost effective provision of connections, for example connections made of conductive metal strips to establish electrical connections. Such accuracy is generally difficult to achieve for self-aligned processes and expensive to achieve by precision pick and place technologies. Moreover, the deposition of conductive strips is expensive; time consuming and problematic as to reliability if the connection is to be robust on flexible substrates. Additionally, such techniques are not generally applicable to connection types other than electrical, for example connections of the fluidic, magnetic, optical, or mechanical types or connections of mixed types. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, the invention resides in a method of providing connectivity to a microsized device, the method comprising the steps of providing an ablative base material having at least a top surface; providing a die having a first and second surface and having bonding pads at least upon the first surface; placing the die with the at least first surface of the die contacting the at least top surface of the ablative base material; and ablating a channel in the ablative material proximate to the die. 
     ADVANTAGEOUS EFFECT OF THE INVENTION 
     The present invention has the following advantage of expanding use of ablative material to include having microsized devices thereon. 
     The placement of microsized devices may precede the patterning of the primary routes for connections to or between the devices, including mechanical, optical, magnetic, fluidic, or electrical. 
     The connections may be combinations of the types above, achieved without substantial process complexity over the individual connection types. 
     The alignment of the microsized devices to the connections may be of a self-aligned nature without the complexity heretofore required of self-aligned connections to microsized devices. 
     Records of the position and alignment of microsized devices are included in the manufacturing process. 
     These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  is a cross-section of a prior art ablative film; 
         FIG. 1   b  is a cross-section of a prior art ablative film; 
         FIGS. 2   a - 2   b  illustrate in cross-section and top-view, respectively, prior art formation of a channel in an ablative film; 
         FIG. 2   c  illustrates in cross-section a prior art process for forming an electrically conductive material in an ablated channel in an ablative film; 
         FIG. 2   d  illustrates schematically in cross-section an embodiment of ablative film  70  of the present invention; 
         FIG. 3   a - b  shows top and cross-sectional views of the microsized device of the present invention having two contact regions; 
         FIG. 3   c  shows a top view of a microsized device having three contact regions; 
         FIG. 3   d  is an alternative embodiment of  FIGS. 3   a - b  showing a top view of a microsized device of the present invention having two contacts; 
         FIG. 3   e  shows a cross-section of a microsized device (die) having a contact region (solid fill) partially extending from the top of the die over its left edge; 
         FIG. 4   a  shows a view of a microsized device (die) having three contact regions (dotted lines) placed with its top-side down on the top surface of an ablative film; 
         FIG. 4   b  shows a view of two microsized devices (die) having contact regions (dotted lines) placed top-side down on the top surface of an ablative film; 
         FIG. 4   c  shows the two die of  FIG. 4   b  including channels formed by laser ablation of the ablative film extending to the contact regions; 
         FIGS. 4   d - 4   e  illustrate a process for forming the channels of  FIG. 4   c  in a self-aligned manner to the die; 
         FIGS. 5   a - 5   b  illustrate deposition by inkjet printing means and by dropper or dipping means of a fluid, for example a conductive ink, into the ablated channels of  FIG. 4   c , as is well known in the arts of inkjet printing and of fluid coating; 
         FIG. 6   a  illustrates one technique for removal of excess fluid deposition by dropper means of a fluid using a flexible blade; 
         FIG. 6   b  shows a cross-sectional view of a die, channel, and deposited fluid as in  FIG. 2   d  but in more detail; 
         FIG. 7   a - 7   c  shows a cross-sectional view of a die, channel, and deposited fluid as in  FIG. 2   d  but in more detail for the case in which the connection to the die is a photonic connection; 
         FIG. 8   a - 8   c  shows a cross-sectional view of a die, channel, and deposited fluid as in  FIG. 2   d  but in more detail for the case in which the connection to the die is a magnetic connection; 
         FIG. 9   a - 9   c  shows a cross-sectional view of a die, channel, and deposited overlayer for the case in which the connection to the die is a fluidic connection; 
         FIG. 10   a - 10   f  shows a cross-sectional view of a die, channel, and deposited overlayer for another exemplary case in which the connection to the die is a fluidic connection; 
         FIG. 11   a - 11   c  shows a cross-sectional view of a die, channel, and channel material for another exemplary case in which the connection to the die is a mechanical connection; 
         FIG. 12   a - 12   b  shows a top and cross-sectional view of a die, channel, and channel material for the case in which the connection to the die is remote, that is the material in the channel is close to the contact region of the die but not in physical contact; and 
         FIG. 13  illustrates by top view multiple connections of multiple types, including connections of the electrical, photonic, magnetic, mechanical, and fluidic types, to multiple types of microsized devices, including devices that generate and respond to electrical, photonic, magnetic, mechanical, and fluidic signals. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Microsized means devices whose features critical to functionality are typically 1 to 100 microns in linear dimension and which are made in processes involving photolithographic exposure of layers of materials to be patterned by subsequent processing. A micro-fluidic device means a microsized device whose principal functionality is the transport, analysis, and dispensation of fluid materials (gases and liquids) or information concerning the nature of the analyzed fluidic materials, such as, but not limited to sensors of chemical or biological materials and their physical and chemical properties. Micro-fluidic microdevices may also receive information in analog or digital form including electrical or optical information and produce fluidic signals such as pressure changes or changes in chemical composition in fluid connections in analog or digital form as output. A microsized photonic device receives, processes, and/or transmit information in the form of optical data, including trains of optical pulses, or analog input or output of light including wavelength optical signals and may respond to optical stimulation in a variety of ways, including electrical and mechanical output. Optical microdevices may also receive information in analog or digital form including electrical or mechanical information and produce optical signals in analog or digital form as output. Mechanical microsized devices are sensitive to and can produce mechanical stimuli in analog or digital form including quasi-static mechanical motion as well as acoustic waves and pulses and may a respond to mechanical stimulation in a variety of ways, including electrical and optical output. Mechanical microdevices may also receive information in analog or digital form including electrical and optical information and produce mechanical or acoustical signals in analog or digital form as output. Magnetic microdevices sense magnetic stimuli in analog or digital form including quasi-static magnetic fields as well as time varying fields and may respond to magnetic stimulation in a variety of ways, including producing electrical and optical output. Magnetic microdevices may also receive information in analog or digital form including electrical and optical information and produce magnetic signals in analog or digital form as output. 
     Referring to  FIG. 2   d , there is shown one embodiment of ablative film  70  of the present invention. The ablative film  70  includes a substrate  80  and two energy-absorbing layers  75  in which a microsized device (die)  90  has been positioned on the top surface of the ablative film  70  and a self-aligned channel  100  is formed in proximity to one edge of the die  90  by laser ablation. As is well known in the art of laser ablation, energy absorbed in one or more energy absorbing layers  75  results in the removal of material from the energy-absorbing layer and, depending on the chemical nature of the surrounding layers, removal of material from adjacent layers. The die  90  in  FIG. 2   d  is provided with one or more contact regions comprising metallic bond pads  110  on the side facing the ablative film. A liquid  120  containing a metallic precursor has been jetted, for example by inkjet printing means, into the channel  100 . A metallic precursor is a fluid which, when dried or annealed, is an electrical conductor, as is well know in the art of printed electronics. The liquid  120  containing a metallic precursor in  FIG. 2   d  fills the channel  100  and has flowed under portions of the die  90  adjacent the channel, thereby providing, when annealed, an electrical and mechanical connection to the die  90  by direct contact to the metallic bond pad  110 . Advantageously, the electrical connection to the die  90  is made simultaneously with the process of deposition of the fluid into channel  100 . 
     Referring to  FIGS. 3   a - 3   b , there is shown top and cross-sectional views of the microsized device  90  (die). The microsized device  90  includes two contact regions  130  (disposed symmetrically) partially protected by protective layers  135  and having a raised support structure  140  between and along the sides of the contact regions  130 . Provision of the die  90  with support structure  140  is advantageous in making various types of connections to the die  90 , as will be described. 
     Referring to  FIG. 3   c , there is shown a top view of an alternative embodiment of the microsized device  90  (die) having three contact regions  130  partially protected by protective layers  135  and having a raised support structure  140  separating some of the contact regions  130 . 
     Referring to  FIG. 3   d , there is shown a top view of an alternative embodiment of the microsized device  90  (die) having two contact regions  130  (disposed non-symmetrically) partially protected by protective layers  135  and having a raised support structure  140  separating the contact regions. The protective layers  135  do not extend to the edge of the die  90  in portions of the contact regions  130  in order to provide a more direct path for liquids subsequently deposited near the edge of the die  90  to flow to the contact regions  130 . 
     Referring to  FIG. 3   e , there is shown a cross-sectional view of an alternative embodiment of the microsized device  90  (die) having a contact region  130  disposed partially extending from the top of the die  90  over its left edge, in order to provide a more direct path for liquids subsequently deposited near the edge of the die  90  to flow to the contact regions  130 . Although  FIG. 3   d  illustrates electrical connection to the die  90 , the location of protective layer  135  as shown in  FIG. 3   d  and the use of the raised support structures  140  are useful in providing all types of contacts to the die  90 . 
     Referring to  FIG. 4   a , there is shown a top view of the microsized device  90  (die) having three contact regions  130  placed with its top-side down on the top surface of an ablative film  70 . The die  90  has been lightly affixed to the ablative film  70 , for example by pressing into the film  70  under heat or by depositing a small amount of adhesive (not shown) to portions of the die  90 , for example to the raised support structure  140  (not visible in this top view as it lies adjacent the top surface of the substrate) separating some of the contact regions  130 . Note the die  90  is not placed with precision; that is, the die center and the angle of the die  90  with respect to the ablative film  70  are not precisely controlled. 
     Referring to  FIG. 4   b , there is shown a view of two microsized devices  90  (die) having contact regions  130  placed top-side down on the top surface of an ablative film  70 . The die  90  has been lightly affixed to the ablative film  70 , for example by pressing into the film  70  under heat or by depositing a small amount of adhesive to portions of the die  90 . It is noted the die  90  are not placed with precision; that is, the die centers and the angles of the die  90  with respect to the ablative film  70  and to one another are not precisely controlled. 
     Referring to  FIG. 4   c , there is shown the two die  90  of  FIG. 4   b . Channels  150  are preferably formed by laser ablation of the ablative film  70  extending to the contact regions  130 . The channels  150  are formed in a manner such that the channel direction is aligned with the direction of the chip, that is, in  FIG. 4   c , the channel  150  is formed perpendicular to the edge of the chip nearest the contact region  130 , despite the fact that the chip has been oriented at an angle to the edge of the ablative film  70 . 
     Referring to  FIGS. 4   d - 4   e , there is shown a process for forming the channels  150  of  FIG. 4   c  in a self-aligned manner to the die  90 . It is noted that although  FIGS. 4   d - 4   e  illustrate the embodiment having two energy absorbing layers  75  covering the substrate  80 , a single energy-absorbing layer is also generally adequate. A scanned source of radiation, for example a laser beam, ablates portions of the ablative film  70  until it reaches the edge of the die  90  where its energy is reflected away from the film  70 , thereby stopping formation of the channel  150  precisely at the die edge, regardless of the position and angle of orientation of the die  90 . If required, the positions of the non-precisely placed die  90  are detected with a camera and stored in a memory file. This file is interrogated upon scanning the energy beams and used to control the scanner to move beams toward the desired locations on the die  90  (typically the locations of the contact pads and typically perpendicular to the edge of the chip nearest the contact region, despite the fact that the chip may be oriented at an angle to the edge of the ablative film  70 ). It is noted that the die  90  are principally supported by the raised support structure  140  separating the contact regions  130  so that there is some space between the contact region  130  and the top surface of the ablative film  70 . 
     Referring to  FIGS. 5   a - 5   b , there is illustrated deposition by inkjet printing means and by dropper or dipping means of a fluid  160 , for example a conductive ink  160   a  (shown later), into the ablated channels  150  of  FIG. 4   c , as is well known in the arts of inkjet printing and of fluid coating.  FIG. 5   a  illustrates the process of dropping the conductive fluid  160  while it is actually occurring and  FIG. 5   b  illustrates the final position of the deposited conductive fluid  160  which has been deposited by multiple drops. As is well known in the art of conductive fluid, the fluid typically hardens to form a solid, also denoted as  161 . Hereafter, the shading of the figures does not differentiate between the fluid and the hardened fluid. 
     Referring to  FIG. 6   a , there is illustrated one technique for removal of excess fluid  161  deposition by dropper means of a fluid using a flexible blade  170 . 
     Referring to  FIG. 6   b , there is shown a cross-sectional view of the die  90 , channel  150 , and deposited fluid  161  as in  FIG. 5   a  but in more detail. In accordance with the present invention, the fluid  161  has wicked underneath a portion of the die  90  and has made physical contact with the contact region  130  of the die  90 . This embodiment illustrates the case in which the connection to the die  90  is an electrical connection. For example, as is well know in the thin film materials art, an electrical connection can be formed from a deposited fluid  161   a  if the fluid contains a metallic precursor or is an electrically conductive polymeric material. The material in the channel  150 , after annealing, is in electrical contact with contact region  130   a . A connection so formed to the microsized device  90  enables the device to send and receive data in the form of digital or analog electrical signals. It is not necessary that the conductive material physically contact the contact region  130   a  as long as it is closely disposed, as is well know in the art of dielectric current detection. The contact regions  130   a  in  FIG. 6   b  may include electrically responsive elements such as voltage or current sources or voltage or current detectors, well known in the art of MST devices. The supportive structure  140  in  FIG. 6   b  aids wicking of the fluid  161   a  to the contact region, since it ensures that there is space between the top surface of the ablative film and the protective coating  135 , as well as between the top surface of the ablative film and the contact region  130   a . The supportive structure  140  in  FIG. 6   b  also helps prevent wicking of the fluid  161   a  to the contact region  130   a  on the right side of the die due to its contact with the top surface of the ablative film. 
     Referring to  FIGS. 7   a - 7   c , there is shown a cross-sectional view of the die  90 , channel  150 , and deposited fluid  160  as in  FIG. 5   a  but in more detail for the case in which the connection to the die  90  is a photonic connection. In this case, the material  160  deposited in the channel  150  is optically transparent (designated by  161   b ). In accordance with the present invention, the fluid  161   b  has wicked underneath a portion of the die  90  and has made physical contact with the contact region  130   b  of the die  90 . In the case that the fluid  161   b  is an optically transparent material, for example a polymer such as polycarbonate or benzo chlorohexal borene, the material  161   b  in the channel  150 , after hardening or annealing, is in optical contact with the contact region  130   b  on the die. In this case, the contact region  130   b  comprises optically responsive elements, for example LED optical sources made from organic polymers, or photodetectors, made, for example, form deposited films such as ZnSe or doped silicon semiconductor junctions. A connection so formed to the microsized device  90  enables the device to send and receive data in the form of digital or analog optical signals. It is not necessary that the optically transmissive material physically contact the contact region  130   b  as long as it is closely disposed since light can travel across the gap between the transmissive material and the optical sensor. The supportive structure  140  in  FIG. 7   c  aids wicking of the fluid  161   b  to the contact region on the left of the die, since it ensures that there is space between the top surface of the ablative film and the contact region  130   b . The supportive structure  140  in  FIG. 7   c  additionally prevents wicking of the fluid to the contact region  130   b  on the right side of the die due to its contact with the top surface of the ablative film. 
     It is noted that electrical contacts  130   a  may be disposed on the left portion of the die  90  and are connected as disclosed above. 
     Referring to  FIGS. 8   a - 8   c , there is shown a cross-sectional view of a die  90 , channel  150 , and deposited fluid  161   c  as in  FIG. 5   a  but in more detail for the case in which the connection to the die  90  is a magnetic connection. In this case, the material  161   c  deposited in the channel  150  is a magnetically active material having a high magnetic permittivity (designated as  161   c ). In accordance with the present invention, the fluid  161   c  has wicked underneath a portion of the die  90  and has made physical contact with the contact regions  130   c  of the die  90 , which regions are shown as a pair of channels which serve to conduct a magnetic field to and from a contact region  130   c  which is sensitive to an applied field, for example, contact region  130   c  could be a Hall type magnetic field sensor. In the case that the fluid  161   c  is a magnetically active material, for example iron or iron alloys, the material in the channel  150 , after hardening or annealing, is in magnetic communication with the contact regions  130   c  on the die  90 . In this case, the contact regions  130   c  comprise a magnetically responsive circuit, for example a Hall sensor, or, a source of magnetic fields, for example, a moveable mechanical transducer having a magnetic portion, as is well known in the art of MST devices. A connection so formed to the microsized device  90  enables the device to send and receive data in the form of digital or analog magnetic signals. It is not necessary that the magnetically active material physically contact the contact regions  130   c  as long as it is closely disposed to the contact regions  130   c , since a magnetic field can be sensed across a gap between the material and the field sensor. 
     Referring to  FIGS. 9   a - 9   c , there is shown a cross-sectional view of a microsized device or die  90 , channel  150 , and an overlying conformal laminate film  180  for the case in which the connection to the die  90  is a fluidic connection. It is noted in the figures that color does not differentiate a channel  150  which is empty and a channel which is filled with externally sampled fluid  161   d . In this case, the contact region  130   d  includes means responsive to the chemistry or rheology of the fluid  161   d  present in the channel  150 , for example the contact region  130   d  may be a chemically sensitive field effect transistor (CHEM-FET) sensitive (which is designated as  130   d ), for example, to the ionic content of the externally sampled fluid  160   d  (for example a gas or liquid); or the contact region  130   d  may be a conductivity detector, a humidity detector, a gas sensor, or a molecularly specific sensor such as a MIP resonator. The contact region  130   d  may also be a fluidic opening built into the microdevice itself, to convey fluids to the device for biological analysis or processing. In this case, the microdevice may include pump means for drawing or dispensing the externally sampled fluid  161   d  in the channels  150 . Externally sampled fluids  160   d  may include either liquids or gases. In one embodiment of this case, there is no material deposited in the channel  150  but a conformal laminate film  180  ( FIG. 9   c ) has been placed at least over those portions of the die  90  where channels  150  have been formed to serve as a cap to the channel. 
     It is noted the left portion of the die  90  may include electrical contacts  130   a  which are connected as described above. 
     Alternatively ( FIGS. 10   a - 10   f ), a sacrificial material may be placed in the channels  150 , for example a phase change liquid such as a wax may be deposited in the channels and hardened by cooling. In accordance with this embodiment, the sacrificial fluid  161   e  may wick underneath a portion of the die  90  and make physical contact with the contact region  130   d  of the die  90 . A fluid sealant may then be coated, for example by dip or spray coating over the entire ablative film or at least the portion having die and channels, and the sacrificial material  161   e  subsequently removed to form channels  150  for the externally sampled fluid  161   d . The sacrificial material  161   e  may be removed (indicated by  161   d ), for example, by chemical dissolution or by heating to vaporize the material. In accordance with either procedure, a fluid channel  150  is formed in the ablative film in fluid communication with the contact region(s) of the die  90 . A connection so formed to the microsized device enables the device  90  to respond to chemical content, for example the presence of salt in a fluid already present in the channel, or to fluid introduced and/or removed from the channel, as sensed, for example, by the pressure or the dielectric constant of the fluid. Similarly if the fluid is a gas, the sensor may detect molecular species such as ethane that diffuse or circulate in the channels. 
     Referring to  FIGS. 10   a - 10   f , there is shown a cross-sectional view of a die  90 , channel  150 , and deposited overlayer for another exemplary case in which the connection to the die  90  is a fluidic connection. In this case, the contact region  130  is a fluidic opening built into the end of the microdevice itself, rather than an opening or a sensor defined on the surface of the device, to convey fluids to the device for biological analysis or processing. The microdevice may include pump means for drawing or dispensing fluid in the channels  150  and data analysis means to analyze chemical or biological properties of fluids in the microdevice, such fluid functions being well known in the field of micro total analysis system. In  FIGS. 10   a - 10   c , provision is also included on the right of the microdevice for channel connections that are electrical in nature, as discussed in association with  FIG. 6   a - 6   c . In fact, the present invention envisions the use of multiple types of connections to single die and between die  90 , including connections of the electrical, photonic, magnetic, and fluidic types. In  FIG. 10   a - 10   c , the fluidic channels are formed using the process of fluid deposition of a sacrificial material followed by coating of a sealing layer and then removal of the sacrificial material, as discussed above. 
     Referring to  FIGS. 11   a - 11   c , there is shown a cross-sectional view of a die  90 , channel  150 , and channel material  161   f  for another exemplary case in which the connection to the die  90  is a mechanical connection. In this case, the contact region  130   f  is mechanically responsive and therefore capable of sensing or producing static motion of the channel material (strain) or sensing or producing oscillatory motion, i.e. acoustic waves. Many microdevices are known in the art of MST technology, such as piezo cantilevers and electrostatic actuators, that are capable of all such functions. In  FIG. 11   a - 11   c , provision is also included on the right of the microdevice for channel connections that are electrical in nature, as discussed in association with  FIG. 6   a - 6   c . The present invention envisions the use of multiple types of connections to and between multiple types of die, including connections of the electrical, photonic, magnetic, mechanical, and fluidic types. 
     Referring to  FIGS. 12   a - 12   b , there is shown a top and cross-sectional view of a die  90 , channel  150 , and channel material  160  for the case in which the connection to the die  90  is remote, that is the material in the channel  150  is close to the contact region  130  of the die  90  but not in physical contact. As shown in  FIG. 12   b , which contemplates the case of a fluid  160  deposited in the channel  150 , no wicking of the fluid  160  has occurred under the die  90 . This may be accomplished by choosing the surface of the die  90  and the fluid  160  so that the interfacial surface tension is low and does not favor wicking, for example aqueous based fluids will not generally wick under a die that is Teflon coated. In this case, the contact region  130  is still capable of sensing or receiving or sending electrical, photonic, magnetic, mechanical, and fluidic connections but at a reduced sensitivity. Many microdevices are know in the art of MST, such as magnetic detectors and temperature sensors that can detect small changes in fields, produced by say a current flow depicted on the right side of  FIG. 12   a , or by small changes in temperature, produced, say, by the flow of a warm fluid as depicted on the left side of  FIG. 12   a.    
     Finally, referring to  FIG. 13 , there is illustrated a top view of an ablative film  70  having multiple microsized devices with multiple connections of multiple types, including connections of the electrical, photonic, magnetic, mechanical, and fluidic types. Such arrays of interconnected microsized devices, including devices that generate and respond to electrical, photonic, magnetic, mechanical, and fluidic signals, function as microsystems, as is well known in the MST art. As has been discussed, and as shown in  FIG. 13 , the present invention contemplates that the connections are made to devices that are not precisely positioned on the ablative film. Channels  150  can be formed in a self aligned manner by focused radiation (e.g. lasers) by detecting, for example with a digital camera, the positions of the microsized devices, storing this information in a memory file, and using the information from such files to scan the focused radiation beams toward the desired locations on the die. (typically the locations of the contact pads). 
     The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention. 
     PARTS LIST   
     
         
           5  ablative film 
           10  substrate 
           20  energy-absorbing layer 
           30  multiple layers 
           40  channel 
           50  base 
           60  conductor 
           70  ablative film 
           75  energy-absorbing layer 
           80  substrate 
           90  die 
           100  channel 
           110  metallic bond pads 
           120  liquid 
           130  contact regions 
           130   a  conductive contacts 
           130   b  optical contacts 
           130   c  magnetic contacts 
           130   d  external contacts 
           130   f  mechanical contact 
           135  protective layers 
           140  raised support structure 
           150  channels 
           160  fluid 
           160   a  conductive ink 
           160   d  externally sampled fluid 
           161  hardened liquid (solid) 
           161   a  conductive material/deposited fluid 
           161   b  optical connection 
           161   c  magnetic connection 
           161   d  external connection 
           161   e  sacrificial connection 
           161   f  mechanical connection 
           170  flexible blade 
           180  conformal laminate film