Patent Abstract:
A lithography device includes one or more conductive strips monolithically embedded within an insulative structure. A method of manufacturing a lithography device includes monolithically forming a conductive strip through an insulative structure. Monolithically forming such a device includes forming the conductive strip on an mixed conductive-insulative layer, and embedding the conductive-insulative layer layer within the insulative structure. Such a device may readily be manufactured, is reliable, and is capable of various lithography applications and other applications requiring sub-micron and nano-scale electrode devices and electrode arrays.

Full Description:
BACKGROUND  
       [0001]     Lithography is ubiquitous, and there are a multitude of processes and products that rely on lithography as one or more of its processing steps. An obstacle in many lithography systems is the ability to create sub 100 nanometer line width patterns.  
         [0002]     Conventional optical lithographic systems is generally based on directing light beams on a photosensitive surface covered by a mask, whereby a desired pattern is etched on the surface. However, typical optical systems are limited in scale due to optical diffraction. To overcome this, x-ray and electron beam optical sources have been used. However, such optical sources invariably require complex systems. Further, such systems are limited to certain materials consistent with the chemical resist materials.  
         [0003]     Thus, it would be desirable to provide a device that overcomes these obstacles, and a method of manufacturing such a device.  
         [0004]     Such a device should be inexpensive to manufacture, reliable, and capable of various lithography applications and other applications requiring sub-micron and nano-scale devices.  
       SUMMARY  
       [0005]     The above-discussed and other problems and deficiencies of the prior art are overcome or alleviated by the several methods and apparatus of the present invention for a lithography device and a method of manufacturing such a device.  
         [0006]     The lithography device includes one or more conductive strips monolithically embedded within an insulative structure.  
         [0007]     A method of manufacturing a lithography device includes monolithically forming a conductive strip through an insulative structure.  
         [0008]     Monolithically forming such a device includes forming the conductive strip on an mixed conductive-insulative layer, and embedding the conductive-insulative layer layer within the insulative structure.  
         [0009]     Such a device may readily be manufactured, is reliable, and is capable of various lithography applications and other applications requiring sub-micron and nano-scale electrode devices and electrode arrays.  
         [0010]     The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  shows an overview of an embodiment of a lithography system detailed herein;  
         [0012]      FIG. 2  shows a top view of a microchip employed in the system of  FIG. 1 ;  
         [0013]      FIGS. 3A and 3B  show a generalized schematic of an electrochemical lithography system;  
         [0014]      FIG. 4  shows a lithographing tool in the form of an electrode or array of electrodes associated with a substrate;  
         [0015]      FIG. 5  shows a plurality of lithographing tools in the form of electrodes or arrays of electrodes associated with a substrate;  
         [0016]      FIGS. 6A and 6B  show enlarged views of a single tip in certain embodiments;  
         [0017]      FIGS. 7A and 7B  show enlarged views of a single tip in other embodiments  
         [0018]      FIG. 8  shows a device having an array of electrodes suitable for electrochemical lithography associated with a substrate;  
         [0019]      FIGS. 9A-9C  show an array of lithography electrodes associated with an x-y motion device used to form a pattern;  
         [0020]      FIGS. 10A-10I  show an x-y array of electrodes used to form a pattern;  
         [0021]      FIGS. 11A-11C  shows an example of a lithography device formed according to a preferred embodiment herein;  
         [0022]      FIG. 12A  show N layers used to form the lithography device of  FIGS. 11A-11C ;  
         [0023]      FIG. 12B  shown N layers stacked and bonded to form a lithography device of  FIGS. 11A-11C ;  
         [0024]      FIG. 13  shows a device used to form electrode tips in certain embodiments hereof;  
         [0025]      FIGS. 14A,14B  and  15  show an electrochemical method of forming electrode tips;  
         [0026]      FIGS. 16A and 16B  shows a deposition based method of forming electrode tips; and  
         [0027]      FIGS. 17A and 17B  show a subtraction method of forming electrode tips. 
     
    
     DETAILED DESCRIPTION  
       [0028]     Referring now to  FIG. 1 , a lithography system  100  is shown. The system generally includes a substrate  102  (e.g., to be lithographically patterned), a lithography electrode device  104  and a microchip  106  in electrical communication, optical communication, or other suitable form of connectivity with electrode tips of the lithography electrode device  104 . The assembly of the lithography electrode device  104  and the microchip  106  may be positionally controlled, e.g., with a suitable x-y motion device  110 . The microchip  106  is connected to a suitable controller  108 , e.g., shown with suitable wires. Of course, other controller sub-systems may be employed, including wireless (e.g., RF) transmitter-receiver sub-systems, optical transmitter-receiver sub-systems, pre-programmed or programmable integrated microprocessors within microchip  106 , micro-electro-mechanical, and/or other suitable controller sub-systems integrated in or associated with the microchip  106 . Note the controller  108  may be integral with microchip  106  (e.g., wherein controller functionality is integrated in microchip  106 ) or a separate sub-system in suitable communication as described herein.  
         [0029]     Referring to  FIG. 2 , a top view of the microchip  106  is depicted. The microchip  106  includes plural switches or other devices  112  for selectively activating associated electrodes (not shown). These switches or other devices  112  are operably connected to the controller  108 .  
         [0030]     Referring now to  FIGS. 3A and 3B , a generalized schematic depiction of an electrochemical lithography system  200  is provided. In general, electrodes  202 ,  204  are separated by an electrolyte  214 . The polarity of the electrodes  202 ,  204  depend on the type of electrochemistry undertaken by the system  200 . As used herein, electrochemical lithography may refer to oxidation or reduction. Upon application of a voltage differential or field between the electrodes, a lithography mark  250  will be formed. Alternatively, as will be apparent to one skilled in the art, a current source may be used to apply current through the lithography electrodes  204 .  
         [0031]     For example, in certain embodiments, where lithography occurs by oxidizing the workpiece or substrate, electrode  202  serves as the positive electrode or cathode, and electrode  204  serves as the negative electrode or anode, whereby the electron flow is between the lithographing tool negative electrode  204  to the substrate positive electrode  202 .  
         [0032]     In other embodiments, where lithography occurs by reducing a workpiece or substrate, electrode  202  serves as the negative electrode or anode, and electrode  204  serves as the positive electrode or cathode, whereby the electron flow is between the substrate positive electrode  202  to the lithographing tool negative electrode  204 . In this embodiment, the substrate positive electrode may be electroplated, e.g., by depositing metal ions from the electrolyte solution  214 .  
         [0033]     Referring now to  FIG. 4 , a system  300  is depicted including a lithographing tool in the form of an electrode or array of electrodes  304  lithographing on a workpiece or substrate as an electrode  302 .  
         [0034]     Referring now to  FIG. 5 , a system  500  is depicted including a plurality of lithographing tools in the form of electrodes or arrays of electrodes  404 ( 1 ) and  404 ( 2 ). These electrodes or arrays  404 ( 1 ) and  404 ( 2 ) lithograph a workpiece or substrate, which operates as an electrode  402  for the electrochemical lithography processes described herein. These may each be connected, for example, to a separate x,y motion device  410 ( 1 ) and  410 ( 2 ), respectively. The operation of each lithographing tool is similar to that described above with respect to  FIGS. 3 and 4 .  
         [0035]     Referring now to  FIGS. 6A and 6B , an enlarged view of a single tip  516  of an electrode  504  is shown. Tip  516  is contiguous with a conductor  518 , which is adjacent to insulative material  520 . Tip  516  may be fabricated in very small dimensions, approaching the order of 10s of nanometers in cross-sectional area.  
         [0036]     Referring now to  FIGS. 7A and 7B , an enlarged view of a single tip  616  of an electrode  604  is shown. Tip  616  is adjacent to insulative material  620 . Tip  616  may be fabricated in very small dimensions, approaching the order of 10s of nanometers in area. Note that the tip  616  is contiguous with a conductor  518 , which is larger in cross-sectional dimension than the tip  616 . This facilitates formation of smaller size marks or traces (e.g.,  250  as shown with respect to  FIGS. 3A and 3B  described above).  
         [0037]     Referring now to  FIG. 8 , a device  700  includes an array of electrodes  704  suitable for electrochemical lithography upon a substrate  702 , the electrodes  704  operably associated with controller  706 . As shown, the electrodes  704  have tips  716  of smaller diameter than the remaining body of the electrodes  704 , as in electrodes  604  of  FIG. 7 , however, electrodes  504  shown in  FIG. 6  may also be employed.  
         [0038]     Referring now to  FIGS. 9A-9C , an array of lithography electrodes is shown associated with an x-y motion device. As shown in  FIG. 9A , the first and third electrodes (as viewed in the Figure from left to right) are activated to form associated marks.  FIGS. 9B and 9C  shows motion to the right, e.g., of a suitable amount to form a mark contiguous with the previously formed mark. Of course, other sutiable X-Y motion may be provided, and other electrodes may be operably activated to form marks in any desired pattern. For example,  FIGS. 10A-10I  show an example of a lithographic pattern formed with a system  700  including an x-y array of electrodes (viewing the electrode tips of the system  700 ).  
         [0039]     Referring now to  FIGS. 11A-11C , a lithography device  804 , and in preferred embodiments a nanolithography device, is generally depicted.  FIG. 11A  shows the device  804 .  FIG. 11B  shows that upon formation of a device  804  (or a device  804 ′ as described herein), it is possible to cut the device into plural devices, each having an array of exposed electrode tips  816  (or ends of conductors  818  not formed into tips  816 ).  FIG. 11C  shows an enlarged view of a portion of the device  804 .  
         [0040]     The device  804  includes a plurality of tips  816 . Each tip  816  is formed as described further herein, and is a monolithic portion of a conductive strip  818 . Electrochemical lithographic processing is accomplished, e.g., upon application of a voltage or field between tip(s)  816  and a substrate, as described generally with respect to  FIGS. 3A and 3B  herein.  
         [0041]     Notably, the dimensions of the tip  816  d 3  is less than the dimension of the conductive strip  818  d 4 . As shown, the width dimension of each strip  818  is substantially greater than the width of the tips  816 . Accordingly, losses associated with resistivity of the conductors used for lithographic processing is minimized. Note that while  FIGS. 11A-11C  depict tips  816  arranged in a staggered fashion, it will be appreciated by one skilled in the art that the pattern of tips  816  on device  804  may be any desired pattern to achieve appropriate lithographic processing, and the manufacturing methods described herein may be readily adapted to accomplish such desired patterns.  
         [0042]     In a preferred embodiment of manufacturing the device  804 , and referring now to  FIG. 12A , N layers  822  used to form a device  804  are shown. Each layer  822  generally includes a “striped” layer  824  and an insulator layer  826 . As shown, strips  828  are patterned on striped layer  824  in a staggered fashion with respect to sequential layers  822 . Insulative strips  830  are disposed between plural conductive strips  828 . A total of M conductive strips  828  and insulative strips  830  may be provided, ultimately resulting in a device  804  having approximately M×N tips  816 .  
         [0043]     During fabrication of the layered structure, each layer may be polished to a substantially uniform thickness, depending on the tolerances of the desired system. Know techniques such as grinding, polishing; chemical-mechanical polishing; polish-stop, or combinations including at least one of the foregoing techniques may be used.  
         [0044]     It should be appreciated that a particular pattern of tips  816  may be manufactured by varying: 
        the horizontal period of conductive strips  828  and insulative strips  830 ;     the pattern between sequential layers  822 ;     the thickness of different layers  822 ;     the thickness of different conductive strips  828  and/or insulative strips  830 ; and/or     the thickness of different insulative layers  826 .        
 
         [0050]     Conductive strips  828  may be formed of any suitable electrically conductive materials including, but not limited to, platinum, palladium, gold, silver, copper, brass, tin, ferrous metals such as stainless steel, nickel, carbon, electrically conducting polymers, electrically conducting ceramics, or combinations and alloys comprising at least one of the foregoing materials. In general, the conductive material should be chosen so that it is electrochemically compatible with chosen substrate (e.g., workpiece  302  shown in  FIG. 4 ), and stable without generating impurities. In certain embodiments, the material should be oxidizable yet capable of oxidizing other materials.  
         [0051]     Insulative strips  830  and insulative layers  826  may be formed of the same or different materials, depending on the application thereof. Such insulative materials include, but are not limited to, electrically insulating plastics or polymers, ceramics, or glass materials, MgO, ZnO, TiO, other known oxides, nitrides of metals, SiN, or any other suitable insulative material.  
         [0052]     Referring now to  FIG. 12B , N layers  822  are stacked and bonded to form a device  804 ′. This device  804 ′ will be used to ultimately form the lithographic writing structure or device  804  shown in FIGS.  11 A-C. Note that the device  804 ′ may be suitable for certain lithography procedures, wherein the tip dimension d 3  ( FIG. 11A ) need not be reduced from the width dimension of the conductor  818 .  
         [0053]     Formation of tips  816  may be accomplished my various methods. For example, as described herein with respect to  FIGS. 13-15 , the tips  816  may be formed by electrochemical oxidation. One of skill in the art may appreciate that the exposed electrode ends may be polished, depending on the tolerances of the desired system. Know techniques such as grinding, polishing; chemical-mechanical polishing; polish-stop, or combinations including at least one of the foregoing techniques may be used.  
         [0054]     Referring now to  FIG. 13 , a device  832  is shown. Device  832  generally includes plural layers, each layer having a relatively thin insulative layer  834  and a thicker conductive layer  836 . In preferred embodiments, there are provided at least M layer. In other embodiments, the number of insulative layers  834  is at least equal to the greatest number of conductive strips  828  across device  804 ′.  
         [0055]     Referring now to  FIGS. 14A and 15 , device  832  is shown interposed adjacent device  804 ′. By maintaining contact between conductive portions  836  and the edge of strips  828 , and application of a voltage by conductive portions  836 , the tips  816  of  FIG. 11A -C may be formed, shown in  FIG. 14B . This is accomplished generally by known electrochemical oxidation principles, whereby the conductive materials of the strips  828  are oxidized. By controlling the voltage or current, the depth t of the tip  816  (relative the remainder of the body of conductive strips  828 ) may be controlled.  
         [0056]     Alternatively, sufficient proximity may be maintained between conductive portions  836  and the edge of strips  828 , whereupon impression of an electric field by conductive portions  836  forms the tips  816 . By controlling the electric field, the depth t of the tip  816  may be controlled.  
         [0057]     Referring now to  FIGS. 16A and 16B , another method of forming tips  816  is shown. For example, material  842  may be deposited at the edges of the strips  828 . Material  842  may be deposited  840  by suitable nozzle structures, vapor deposition, solid deposition, or other deposition methods. In certain embodiments, it may be desirable to etch or otherwise remove the edges of strips  828  prior to depositing material  842 .  
         [0058]     Referring now to  FIGS. 17A and 17B , another method of forming tips  816  is shown. For example, material  846  may be removed at the edges of the strips  828 . Material  846  may be removed  844  by suitable nozzle structures, focused ion beam systems, electron beam systems, x-ray systems, other oxidation/anodization methods, or any other suitable subtractive processing methods.  
         [0059]     There herein described systems may be used to write lithographic patterns, to read patterns and to erase patterns. As described above, lithographic patterns may be written by oxidizing or reducing the workpiece or substrate. For example, suitable voltages are used sufficient to oxidize or reduce the substrate. However, with the same or a substantially similar lithography device, the patterns may be read. For example, when indication of a mark or pattern that is read is provided by completion of a circuit at the area of the mark or pattern. Further, to erase lithographic patterns or marks, the electrochemical processes used to write the patterns may be reversed.  
         [0060]     With the herein lithography device including an of electrode ends (in certain embodiments having smaller tips), other lithography operations are also possible. One operation includes electrostatic xerography (whereby material traces or marks may be deposited and charged to facilitate electrostatic lithography). Another possible operation includes formation of  
         [0061]     A key benefit of the presently described lithography device and methods of manufacturing lithography devices is the ability to fabricate devices with very small tip dimensions. For example, as shown in  FIG. 11A , the thickness dimension d 1  may be on the order of nanometers, which is realizable since current technology allows for deposition of layers of 10s of nanometers.  
         [0062]     Further, the width dimension d 3  as shown in  FIG. 11A  may also be on the order of nanometers, as the present methods and device departs from traditional reliance on trace widths (e.g., whereby presently available technology is on the order of 0.1 microns). This is realizable as the dimension d 3  depends on the thickness the insulative layer  836  between conductive layers  834 , rather than a horizontal width dimension.  
         [0063]     While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.

Technology Classification (CPC): 8