Abstract:
Circuit boards ( 1100, 1400 ) and methods for fabricating circuit boards that include conduits ( 1004 ) are provided. The conduits formed by patterning a metal layer ( 1102 ) are lined by inert coating ( 1106 ) and caped by a photodefinable polymer layer ( 1110 ) that is affixed to the inert coating by with the help of an initially uncured polymer layer ( 1106 ). Holes are formed by patterning the photodefinable polymer layer for admitting and removing fluid from the conduit.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates in general to integrated electromechanical apparatus manufacturing. More particularly, the present invention relates to integrated conduits for printed circuit boards.  
         BACKGROUND OF THE INVENTION  
         [0002]    Advances in semiconductor manufacturing technology have enabled complex electronic systems (e.g., computers, wireless telephones) to be integrated into relatively small size packages. The advances in semiconductor manufacturing technology have been accompanied by advances in circuit board technology. Advanced circuit boards facilitate interconnection of high pin count semiconductor packages.  
           [0003]    Systems that include electrical circuits of varying complexity along with conduits, (e.g., fluid conduits) are used for a variety of applications. Such conduits are typically provided in the form of separate components that assembled with electrical components in an apparatus. Such separate conduits, increase the cost, and increase the space occupied by such apparatus. Given the current trend toward reducing the size of complex apparatus it is preferable to conserve as much space as possible without adversely effecting the cost. For example, reducing the size and cost of medical testing equipment that includes one or more fluid conduits can be expected to lead to proliferation of more advanced diagnostic equipment among doctors. More generally, reducing the size and cost of other types of devices that include conduits generally results in greater convenience for users of the devices. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0004]    The present invention will be described by way of exemplary embodiments, but not limitations, illustrated in the accompanying drawings in which like references denote similar elements, and in which:  
         [0005]    [0005]FIG. 1 is a first part of a flow chart of a method of fabricating a circuit board based integrated heater and fluid conduit according to the preferred embodiment of the invention;  
         [0006]    [0006]FIG. 2 is a second part of the flow chart begun in FIG. 1;  
         [0007]    [0007]FIG. 3 is a fragmentary sectional elevation view at an intermediate stage of the method shown in FIGS. 1-2 at which a dielectric substrate is metallized on both sides;  
         [0008]    [0008]FIG. 4 is a fragmentary sectional elevation view at an intermediate stage of the method shown in FIGS. 1-2 at which passivated contacts have been formed on the dielectric substrate shown in FIG. 3;  
         [0009]    [0009]FIG. 5 is a plan view corresponding to FIG. 4, and showing the layout of the contacts shown in FIG. 4;  
         [0010]    [0010]FIG. 6 is a fragmentary sectional elevation view at an intermediate stage of the method shown in FIGS. 1-2 at which resistive traces have been printed on the dielectric substrate overlapping the passivated contacts shown in FIGS. 4 and 5;  
         [0011]    [0011]FIG. 7 is a plan view corresponding to FIG. 6, and showing the layout of the resistive traces with respect to the passivated contacts;  
         [0012]    [0012]FIG. 8 is a fragmentary sectional elevation view at an intermediate stage of the method shown in FIGS. 1-2 at which a second dielectric layer has been attached over the resistive traces, and thermally conductive patches have been formed on the second dielectric layer aligned with the resistive traces.  
         [0013]    [0013]FIG. 9 is an x-ray plan view corresponding to FIG. 8 and showing the layout of thermally conductive patches with respect to the resistive traces; and  
         [0014]    [0014]FIG. 10 is an x-ray plan view at an intermediate stage of the method shown in FIGS. 1-2 at which a third dielectric layer and a metal layer have been positioned over the second dielectric layer, and a channel etched through the metal layer;  
         [0015]    [0015]FIG. 11 is a fragmentary sectional elevation view of the circuit board based integrated heater and fluid conduit according to the preferred embodiment of the invention;  
         [0016]    [0016]FIG. 12 is a fragmentary sectional elevation view of separate carrier layer bearing polymeric layers that is incorporated into the circuit board based integrated heater and fluid conduit shown in FIG. 11.  
         [0017]    [0017]FIG. 13 is a block diagram of a temperature control system according to the preferred embodiment of the invention;  
         [0018]    [0018]FIG. 14 is a fragmentary sectional elevation view of a printed circuit with integrated heater and fluid conduit according to a first alternative embodiment of the invention;  
         [0019]    [0019]FIG. 15 is a fragmentary sectional elevation view of a circuit board with integrated heater, supporting a temperature sensitive component, according to a second alternative embodiment of the invention;  
         [0020]    [0020]FIG. 16 is a fragmentary sectional elevation view of a circuit board based biosensor apparatus including an integrated heater, and biosensor chamber according to a third embodiment of the invention; and  
         [0021]    [0021]FIG. 17 is a partial x-ray perspective view of a circuit board based DNA analysis apparatus according to a fourth alternative embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention.  
         [0023]    [0023]FIGS. 1-2 show a flow chart of a method  100  of fabricating a circuit board based integrated heater and fluid conduit  1100  (FIG. 11) according to the preferred embodiment of the invention, and FIGS. 3-11 shown the integrated heater and fluid conduit  1100  at different stages of fabrication. In the description that follows the leading digit of each reference numeral indicates the FIG. in which the referenced part first appears. The integrated heater and fluid conduit  1100  is fabricated on a portion of a dielectric circuit substrate  302 , shown in FIG. 3-11. Other electrical circuits or fluidic, thermal or mechanical devices that interoperate with, or are independent of the integrated heater and fluid conduit  1100  can be fabricated on other parts of the dielectric circuit substrate  302 . Advantageously, the integrated heater and fluid conduit  1100  is suitable for integration with other components on a circuit substrate  302 .  
         [0024]    In step  102  the dielectric circuit substrate  302  is obtained. The dielectric circuit substrate  302  preferably comprises a base substrate that includes organic resin impregnated fiber glass. The dielectric circuit substrate  302  is alternatively a flexible circuit substrate such as a flexible polyester, or a flexible polyimide circuit substrate.  
         [0025]    In step  104  a first surface  304  of the dielectric circuit substrate  302  is metallized with a first metal film  306  and preferably a second surface  308  of the dielectric circuit substrate is metallized with a second metal film  310 . The first  306  and second  310  metal films are preferably separately manufactured and laminated to the dielectric circuit substrate  302 . An adhesive (not shown) is optionally used to bond the metal films  306 ,  310  to the dielectric circuit substrate. Alternatively, the metal films  306 ,  310  are formed on the substrate  302 , e.g., by electroless, and electro plating processes.  
         [0026]    In step  106  the first metal film  306  is patterned to form a first contact terminal  402 , and a second contact terminal  404  as well as a third contact terminal  502 , a fourth contact terminal  504 , a fifth contact terminal  506 , and sixth contact terminal  508 . The layout of the contact terminals  402 ,  404 ,  502 - 508  is shown in FIG. 5. The contact terminals comprise patches of metal etched from the first metal film  306 . In step  106 , the second metal film  310  is also patterned to form a first metallization trace  408  and a second metallization trace  410  on the second surface  308  of the substrate  302 .  
         [0027]    The contact terminals  402 ,  404 ,  502 - 508  and the metallization traces  408 ,  410  are preferably formed by applying photoresist to the first  306  and second  310  metal films, imagewise exposing the photoresist, developing the photoresist, and thereafter etching the first  306  and second  310  metal films with a liquid etchant using the photoresist as a mask. In step  106  other portions of the first  306  and second  310  metal films (not shown) can also be patterned to form electrical interconnects, or other structures for components that are fabricated on other portions (not shown) of the dielectric circuit substrate  302 .  
         [0028]    In step  108  a passivation coating  406  is applied to the contact terminals  402 ,  404 ,  502 - 508 . The passivation coating  406  aids in maintaining low resistance electrical contact between the contact terminals  402 ,  404   502 - 508  and a resistive ink, that is subsequently applied, during a process of curing the resistive ink and thereafter. The passivation coating  406  preferably comprises nickel, tin, gold, silver or a combination thereof. Alternatively, the passivation coating  406  is not used.  
         [0029]    In step  110  resistive traces including a first set of resistive traces  602 , a second set of resistive traces  702 , and a third set of resistive traces  704  are formed on the first surface  304  overlapping the contact terminals  402 ,  404 ,  502 - 508 . The first set of resistive traces  602  extends between the first contact terminal  402 , and the second contact terminal  404 . The second set of resistive traces  702  extends between the third contact terminal  502 , and the fourth contact terminal  504 , and similarly the third set of resistive traces  704  extends between the fifth contact terminal  506  and the sixth contact terminal  508 . The resistive traces  602 ,  702 ,  704  are conductors used for controlled heating. The resistance of the traces within each set of traces  602 ,  702 ,  704  is preferably chosen to obtain a certain heating power. The resistance can be controlled by controlling the thickness, width, length or resistivity of the resistive traces  602 ,  702 ,  704 . Alternatively, the resistance of all the traces  602 ,  702 ,  704  is the same and heating power is controlled by selecting voltages applied to the resistive traces  602 ,  702 ,  704 . The resistive traces  602 ,  702 ,  704  are preferably formed by printing a resistive ink. More preferably, the resistive traces  602 ,  702 ,  704  are formed by screen printing. The resistive ink composition preferably comprises conductive particles such as silver or carbon particles in a polymeric binder, along with a solvent. The solvent is driven off in a subsequent curing step. Alternatively, an ultraviolet curable polymeric binder is employed. In the latter case the process of curing comprises exposure to ultraviolet light. Examples of suitable resistive inks are carbon filled phenolic resins such as that sold under the trade name “TU-00-8” by Asahi corporation of Tokyo, Japan, or resistive ink sold under the trade name Electrad&#39; or by Electra corporation of Kent, England.  
         [0030]    Alternatively, the resistive ink comprises a positive temperature coefficient of resistance (PTCR) material. Resistive traces that include a PTCR material are, to a degree, self regulating, in so far as they tend to maintain a stable temperature, even when thermally coupled to variable heat sinks or sources, and supplied by a varying voltage supply. Suitable PTCR resistive inks include that sold under the trade designation “7282 PTC ink” by Dupont MCM of Research Triangle Park, N.C.  
         [0031]    Referring again to FIG. 1, in step  112  the resistive traces are cured. Curing preferably comprises ultraviolet exposure and/or heating.  
         [0032]    According to an alternative embodiment the resistive traces  602 ,  702 ,  704  are formed from nickel phosphorous alloy. Alternatively, resistive traces  602 ,  702 ,  704  and their associated contact terminals  402 ,  404 ,  502 - 508  are integrally formed from a single metal layer such as for example nickel phosphorous alloy.  
         [0033]    In step  114  a first via  608  is drilled through the first metallization trace  408 , the dielectric circuit substrate  302 , and the first terminal contact  402 , and a second via  610  is drilled through the second metallization trace  410 , the dielectric circuit substrate  302 , and the second contact terminal  404 . A third  706 , a fourth  708 , a fifth  710 , and a sixth  712  via that are used to couple additional metallization traces (not shown) to the third  502 , fourth  504 , fifth  506 , and sixth  508  contact terminals respectively are also drilled. Other vias used to interconnect other traces, and contact terminals (not shown) on different parts of the dielectric circuit substrate are also preferably be drilled at this time.  
         [0034]    In step  116  the first  608  and second  610  vias are plated to form a first conductive connection between the first metallization trace  408 , and the first contact terminal  402 , and a second conductive connection between the second metallization trace  410 , and the second contact terminal  404 . In step  116  the third through sixth vias  706 - 712  are also plated to form conductive connections to metallization traces (not shown) on the second surface  308  of the dielectric circuit substrate  302 .  
         [0035]    In step  118  a first organic resin coated foil is laminated on the first surface  304  of the dielectric circuit substrate  302  over the contract terminals  402 ,  404 ,  502 - 508  and the resistive traces  602 ,  702 ,  704 . An organic resin layer  802  of the first organic resin coated foil faces the first surface  304 . A foil  801  of the first organic resin coated foil preferably comprises copper. The organic resin layer  802  of the organic resin coated foil is a dielectric and preferably comprises a partially cured epoxy. Alternatively, in lieu of laminating an organic resin coated foil in step  118  and step  122  described below, separate organic insulator and metal layers are applied sequentially.  
         [0036]    In step  120 , the foil  801  of the first organic resin coated foil is patterned to form a first thermally conductive patch  804 , a second thermally conductive patch  902 , and a third thermally conductive patch  904 , which respectively overlie the first set of resistive traces  602 , the second set of resistive traces  702 , and the third set of resistive traces  704 . Each particular thermally conductive patch serves to laterally distribute heat generated by the set of resistive traces that the particular conductive thermally conductive patch overlies. The thermally conductive patches  804 ,  902 ,  904  thereby, establish zones of relatively uniform temperature. Such zones are useful in maintaining the temperature of temperature sensitive apparatus that are positioned within them. The thermally conductive patches  804 ,  902 ,  904  are preferably not connected to metallization traces which could dissipate heat. The foil  801  of the first organic resin coated foil can be patterned to form the thermally conductive patches  804 ,  902 ,  904  in the same manner used to pattern the metal films  306 ,  310  as described above.  
         [0037]    In step  122  a second organic resin coated foil that comprises a foil  1102 , and: a organic resin layer  1101  is laminated over the first organic resin coated foil with the organic resin layer  1101  of the second organic resin coated foil facing the foil layer  801  of the first organic resin coated foil. The method  100  then continues with step  202  shown in FIG. 2.  
         [0038]    In step  202  the foil layer  1102  of the second organic resin coated foil is patterned to define the outline of a conduit  1004  that pass over the thermally conductive patches  804 ,  902 ,  904 . The conduit  1004  pass through the zones of relatively uniform temperature established by the three thermally conductive patches  804 ,  902 ,  904 . Embodiments are described below with reference to FIGS. 12-17, in which temperature sensitive apparatus other than conduits are located in a zone of relatively uniform temperature established by a thermally conductive patch.  
         [0039]    In step  204  at least a portion of the foil  1102  of the second organic resin coated foil, including the area of the conduit  1004  is coated with a polymeric coating  1106 . The polymeric coating  1106  is preferably chemically inert, in particular inert with respect to a genetic material that the integrated heater and fluid conduit  1100  is used to process according to the preferred embodiment. The polymeric coating  1106  preferably comprises a liquid epoxy such as that sold under the trade name “Probelec CFP” by Vantico corporation of Los Angeles, Calif.  
         [0040]    In step  205  the polymeric coating  1106  is exposed to ultraviolet to partially cure the polymeric coating  1106 .  
         [0041]    In step  206  a separate carrier  1108  is coated with a photodefinable polymer layer  1110 . The photodefinable polymer layer  1110  is preferably the same material coated on the foil  1102  of the second organic resin coated foil in step  204 . The separate carrier  1108  is preferably a piece of copper foil. The separate carrier is also shown in FIG. 12.  
         [0042]    In step  208  the photodefinable polymer layer  1110  on the separate carrier  1108 , and the polymeric coating  1106  on the second foil  1102  are dried, to at least partially drive off a solvent.  
         [0043]    In step  210  the photodefinable polymer layer  1110  on the separate carrier  1108  is patterned, by patternwise exposure to optical radiation, followed by development. Patterning performed in step  210  forms a first opening  1112  in the photodefinable polymer layer  1110  that is used to introduce a solution of biochemicals or other fluid into the conduit  1004 , a second opening  1114  that is used to extract the solution of biochemicals or other fluid from the conduit  1004 , and an opening over each thermally conductive patch for accommodating a temperature sensor. A third opening  1118  that is subsequently used to accommodate a temperature sensor  1120  over the first thermally conductive patch  804  is visible in FIGS. 11, 12. Alternatively, a surface mount temperature sensor such as a surface mount packaged diode is used.  
         [0044]    In step  212 , the photodefinable polymer layer  1110  on the separate carrier is cured, by exposure to ultraviolet, elevated temperature, or a combination thereof.  
         [0045]    In step  214  the photodefinable polymer layer  1110  on the separate carrier is coated with an additional layer of polymer  1116 , which is preferably the same material as the photodefinable polymer layer  1110 . The additional layer  1116  is applied thinly so that it need not be patterned to form the orifices aligned with openings  1112 ,  1114 ,  1118  in the photodefinable polymer layer  1110 .  
         [0046]    In step  215  the photodefinable polymer layer  1110 , and the additional layer  1116  are blanket exposed to ultraviolet light to partially cure the layers  1110 ,  1116 . Alternatively, the additional layer  116  is patternwise exposed to ultraviolet radiation according to the same pattern used to expose the photodefinable polymer layer  1110 .  
         [0047]    In step  216 , the additional layer of polymer  1116  on the separate carrier  1108  is brought into contact with the layer of polymer  1106  on the second foil  1102 , and the separate carrier  1108  with the layers of polymer  1110 ,  1116  is laminated to the layer of polymer  1106  on the second foil  1102 , thereby closing off the top of the conduit  1004 . The additional layer of polymer  1116  which is not fully uncured at the time of lamination aids in bonding the layer of polymer  1110  on the separate carrier  1108 , with the layer of polymer  1106  on the second foil  1102 .  
         [0048]    In step  218  polymer layers  1106 ,  1110 ,  1116  are subjected to a thermal curing step for the purpose of curing and bonding.  
         [0049]    In step  220  the carrier  1108  (now a part of the integrated heater and fluid conduit  1100 ) is patterned to define: openings aligned with the openings (e.g.,  1112 ,  1114 ,  1118 ) in the polymer layer  1110 , interconnect traces for electrical components, and optionally other thermal, fluidic, and/or mechanical structures.  
         [0050]    In step  222  plated vias (not shown) are formed through the circuit board based integrated heater and fluid conduit  1100 .  
         [0051]    In step  224  electrical components are mounted on the interconnect traces formed from the carrier  1108 . The temperatures sensor  1120  is located in the opening  1118  and is surrounded by a silicone fill  1122 . Leads of the temperature sensor  1120  are attached to a third metallization trace  1124 , and a fourth metallization trace  1126  that are formed from the carrier  1108 . A feedback temperature controller integrated circuit  1128  is coupled to the temperature sensor  1120  by the third  1124 , and fourth  1126  metallization traces. The integrated circuit  1128  is also coupled to at least a fifth metallization trace  1134 . At least the fifth metallization trace  1134  is coupled to the first metallization trace  408  or the second metallization trace  410  that are located on the second surface  308  of the substrate  302 , by vias (not shown) that pass through the integrated heater and fluid conduit  1100 . Alternatively, other arrangements of interlayer vias and traces at different metallization layers are used to couple the resistive traces with the integrated circuit  1128 , or to couple the temperature sensor  1120  to the integrated circuit. The temperature controller integrated circuit  1128  is electrically coupled to the first set of resistive traces  602 . The temperature controller integrated circuit  1128  controls a voltage or current supplied to the first set of resistive traces  602 , based on temperature measurements made with the temperature sensor  1120 , in order to maintain the temperature in the zone of relatively uniform temperature above the first thermally conductive patch  804 . Additional temperature controllers (not shown) are preferably provided for controlling the temperature above the second  902  and third  904  thermally conductive patches. The additional temperature controllers can be integrated with the temperature controller integrated circuit  1128 , or provided in separate integrated circuits. Alternatively, the integrated circuit is located in a separate assembly that is coupled to the integrated heater and fluid conduit  1100  through a connector e.g., a board edge connector.  
         [0052]    In step  226  a first fluid coupling fitting  1130  is attached over the first opening  1112 , and a second fluid coupling fitting  1132  is attached over the second opening  1114 . The fluid coupling fittings  1130 ,  1132  are preferably attached by adhesive, and are alternatively coupled mechanically.  
         [0053]    The circuit board based integrated heater and fluid conduit  1100  is particularly suitable for processing a liquid by cycling its temperature between temperatures corresponding to the temperature zones corresponding to the three thermally conductive patches  804 ,  902 ,  904 . One process that involves such temperature cycling is chemical amplification of deoxyribonucleic acid (DNA) by polymerase chain reaction (PCR). In conducting a PCR reaction using the circuit board based integrated heater and fluid conduit  1100 , a PCR reaction mixture is introduced into the conduit  1104  through the first opening  1112 , and flows through the conduit  1004  cyclically reaching the different temperature zones corresponding to the thermally conductive patches  804 ,  902 ,  904 , and is extracted through the second opening  1114 . The conduit  1104  can be extended to include more or less segments depending on the degree of DNA amplification required. A series of short zig-zag segments can be included to cause the PCR reaction mixture to dwell in a particular temperature zone as desired.  
         [0054]    The conduit  1104  fabricated as described above is alternatively used for other applications such as for example circulating a cooling liquid near semiconductor components, and coupling light signals from a first device to a second device. The conduit  1104  is alternatively fabricated according to the steps described above on a base that does not include the resistive traces  602 ,  702 ,  704 , or the thermally conductive patches  804 ,  902 ,  904 . The conduit  1104  has utility beyond use in conjunction with thermal elements. The method for forming the conduit  1104  described above with reference to steps  202 - 218  of FIG. 2 is well suited to mass production, and is capable of manufacture conduits having widths at least as small as 100 microns. Small widths are advantageous in that they allow small volumes of fluid (e.g., PCR reaction mixture), the availability of which may be limited, to be processed using the integrated heater and fluid conduit  1100 .  
         [0055]    Alternatively, conduits fabricated by methods others than that described above are mounted on a base that includes the resistive traces  602 ,  702 ,  704 , and the thermally conductive patches  804 ,  902 ,  904 .  
         [0056]    [0056]FIG. 13 is a block diagram of a temperature control system  1300  that is embodied in the integrated heater and fluid conduit  1100  according to the preferred embodiment of the invention. A temperature setting signal source  1302  and the temperature sensor  1120  are electrically coupled to inputs of the feedback temperature controller  1128 . The temperature setting signal source  1302  can for example comprise a voltage divider, a potentiometer or a microprocessor controlled voltage source. An output of the feedback temperature controller  1128  is electrically coupled to the first set of resistive traces  602 . The feedback temperature controller  1128  supplies power to the set of resistive traces  602 . Power supplied to the first set of resistive traces  602  is derived from a power source, e.g., battery (not shown). The set of resistive traces  602  are thermally coupled through the first thermally conductive patch  804  to the temperature sensor  1120 , and what is designated in FIG. 13 as a temperature sensitive apparatus  1304 . In the integrated heater and fluid conduit  1100 , the temperature sensitive apparatus  1304  is embodied by the fluid conduit  1004  and a fluid (e.g., PCR reaction mixture) passing through the fluid conduit  1004 . Other types of temperature sensitive apparatuses can be supported over the thermally conductive patch  804 , as for example described below with reference to FIGS. 15, 16.  
         [0057]    The temperature control system  1300  beneficially maintains the operating temperature of the temperature sensitive apparatus  1304  at a desired value.  
         [0058]    In the alternative case that the resistive traces  602  comprise a PTCR material, then the resistive traces are preferably directly coupled to a power source. Optionally the feedback temperature controller  1128  is used in conjunction with PTCR resistive traces as well.  
         [0059]    [0059]FIG. 14 is a fragmentary sectional elevation view of a printed circuit with integrated heater and fluid conduit  1400  according to a first alternative embodiment of the invention. In the embodiment shown in FIG. 14, the dielectric circuit substrate  302  includes an extending portion  1402  that extends beyond the periphery of overlying layers, and contact terminals suitable for connecting to a board edge connector are formed on the extending portion  1402 . For example as seen in the sectional elevation view of FIG. 14, the second contact terminal  404  for the first set of resistive traces  602  is extended to form a contact terminal  1404  for connection to an external board edge connector (not shown). Other contact terminals (i.e.,  402 ,  502 ,  504 ,  506 ,  508 ) are also connected by metallization traces formed from the first metal film  306  to contact terminals on the extending portion  1402 . In the first alternative embodiment  1400 , the third  1124  and fourth  1126  metallization traces are also extended to form contact terminals e.g.,  1406  disposed proximate an edge  1408  of the carrier  1108 . The latter contact terminals are also suitable for coupling to a board edge connector. The first alternative embodiment is suitable for use in as system in which other electrical components e.g., the integrated circuit temperature controller  1128  is located in a separate apparatus that is coupled to the printed circuit with integrated heater and fluid conduit  1400  through one or more board edge connectors.  
         [0060]    [0060]FIG. 15 is a fragmentary sectional elevation view of a second alternative circuit board with integrated heater  1500 , supporting a temperature sensitive component  1502  according to the second alternative embodiment  1500 , rather than using the foil layer  1102  of the second organic resin coated foil to form the conduit  1004 , the foil layer  1102  is used to form a metal interconnect layer  1504  for electrical components, including the temperatures sensitive component  1502 . There are a variety of types of temperature sensitive electrical components that can be advantageously mounted on the circuit board with integrated heater  1500 . The temperature sensitive electrical component  1502  comprises, for example, a temperature controlled crystal oscillator, a ceramic filter such as a surface acoustic wave device, or a crystal based filter. Temperature controlled crystal oscillators, and surface acoustic wave devices are two types of frequency selective devices. Alternatively, non-electrical temperature sensitive components are advantageously mounted on the circuit board with integrated heater  1500 . For example the temperature of temperature sensitive electro-optical devices such as optical attenuators can advantageously be controlled by mounting on the circuit board with integrated heater  1500 . Such components can interact e.g., through an attenuated light beam with optoelectronic components e.g., photodiodes mounted on the circuit board with integrated heater  1500 . In the second alternative embodiment it is optional but not necessary to provide more than one set of resistive traces  602 , or one thermally conductive patch  804 .  
         [0061]    A first plated via  1506 , and a second plated via  1508  are provided for electrically connecting the first contact terminal  402 , and the second contact terminal  404  with the interconnect layer  1504  formed from the foil  1102 .  
         [0062]    [0062]FIG. 16 is a fragmentary sectional elevation view of a circuit board based biosensor apparatus  1600  according to a third alternative embodiment of the invention. In the biosensor apparatus  1600  the foil  1102  of the second organic resin coated foil is patterned to define a number of pads  1602 . The pads  1602  are plated with gold  1604 , and thereafter a bioactive self assembled monolayer  1606  that includes DNA capture probes, insulator molecules, and conductive molecules is formed on the gold  1604 . An inverted cup  1608  that is attached to the resin layer  1101  by an adhesive  1610  surrounds the pads  1602 . The cup  1608  includes openings  1612  for admitting or extracting solutions including genetic material to be tested. Metallization traces (not shown) extend from the pads through the adhesive  1610  to a measurement circuit such as a voltammetry circuit (not shown).  
         [0063]    In operation, DNA to be tested along with signaling probe molecules that include DNA segments complementary to DNA being tested for and electrochemically oxidizable or reducible groups (e.g., ferrocene) are introduced through one of the openings  1612 . The signaling probes selectively bond to complementary first segments of DNA being tested. Second segments of the DNA being tested selectively bonds to the capture probes included in the self assembled monolayer  1606 , thereby electrically coupling the signaling probes to the pads  1602 . The foregoing processes are temperature sensitive and are preferably performed at between 37 and 40 C. When a signal is applied by the voltammetry circuit to the pads  1602 , a current will be detected in the case that the DNA being test for is present, because such DNA will have bonded to the signaling probes that include the electrochemically oxidizable or reducible groups to the capture probes, and a current related to oxidation of the ferrocene groups will be induced. Further details of the self assembled monolayer  1606 , and the voltammetry technique which are outside the main focus of the present invention are known to persons of ordinary. skill in the genomics arts.  
         [0064]    [0064]FIG. 17 is a partial x-ray perspective view of a circuit board based DNA analysis apparatus  1700  according to a fourth alternative embodiment of the invention. A first section  1702  of the apparatus  1700  includes resistive traces, (not shown), thermally conductive patches (not shown), and a conduit  1704  constructed in similar fashion to the embodiments shown in FIGS. 11, 14. The fluid conduit  1704  passes back and forth through three different temperature zones, the temperatures of which are chosen to cause repeated cycles of the PCR reaction to occur. A fluid coupling fitting  1706  is provided over a first opening (not shown) of the conduit  1704 , and is used to introduce a PCR reaction mixture into the conduit  1704 . Temperature sensors  1708  are used to sense the temperature of three different temperature zones established by thermally conductive patches underlying the conduit  1704 . Metallization traces  1710  formed from a patterned carrier are connected to the temperature sensors  1708  and extend to end portions that serve as a first set of board edge connector terminals. A second set of board edge connector terminals  1726  formed from a metal layer located on a dielectric circuit substrate  1728  are used to connect contact terminals (not shown) for resistive traces (not shown) for the three temperature zones to an external power source.  
         [0065]    A second section includes a biosensor apparatus  1712  constructed in similar fashion to that shown in FIG. 16. The biosensor apparatus  1712  comprises a plurality of exposed pads  1714  located under an inverted cup  1716 . The cup  1716  is bonded to a polymer layer  1718  by an adhesive  1720 . Metallization traces  1722  extend from the exposed pads  1714  through the adhesive  1720  to a third set of board edge connector terminals  1724 . The exposed pads  1714  are preferably gold plated, and are covered with a self assembled monolayer of the type discussed above with reference to FIG. 16.  
         [0066]    A second opening  1730  of the conduit  1704  is located under the cup  1716  such that reaction products pass from the conduit  1704  into a space under the cup  1716  that includes the exposed pads  1714 . The cup  1716  includes vent  1719  to prevent pressure build up.  
         [0067]    In use the apparatus  1700  is connected through a board edge connector to external circuits that: supply power for heating the three temperature zones through the second set of board edge connector terminals  1726 , read the temperatures of the three different temperature zones through the metallization traces  1710 , and apply voltammetry signals to the pads  1714  through the third set of board edge connector terminals  1724 .  
         [0068]    In operation a PCR mixture is introduced through the fluid coupling fitting  1706 , flows through the conduit  1704  while a PCR reaction takes place to amplify DNA in the PCR mixture, and flows into the biosensor apparatus  1712 , where voltammetry is performed to test for the presence of specific DNA sequences.  
         [0069]    While the preferred and, other embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those of ordinary skill in the art without departing from the spirit and scope of the present invention as defined by the following claims.