Abstract:
An electrode and a method for forming the electrode. The electrode comprises: a substrate; and a plurality of metal particles adhering to the substrate. The method comprises steps of: providing a substrate; providing a solution including a solvent and a plurality of metal particles on the substrate; removing the solvent; and making the plurality of metal particles adhere to the substrate.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to an electrode and a method for forming the same and, more particularly, to an electrode with a plurality of metal particles and a method for forming the electrode.  
         [0003]     2. Description of the Prior Art  
         [0004]     Electrodes are conventionally manufactured by electroplating or evaporation on rigid substrates using expensive equipments at high temperatures. However, it is not easy for such electrodes to be connected to other materials such as metal wires for module integration.  
         [0005]     A conventional method for forming an electrode is Taiwan Patent Pub. No. 414,951 filed by TSMC, disclosing a method for forming electrodes used in capacitors having dielectric with a high dielectric constant. The method is as described in  FIG. 1  to  FIG. 6 , comprising steps of: providing a substrate  11  (as shown in  FIG. 1 ); forming an electrode defining layer  12  on the substrate  11  (as shown in  FIG. 2 ); forming an opening  14  in the electrode defining layer  12  using photo-lithography with a photo-resist layer  16  (as shown in  FIG. 3 ); filling the opening  14  with a conductive material  18  covering the electrode defining layer  12  (as shown in  FIG. 4 ); removing the conductive material  18  outside the opening  14  (as shown in  FIG. 5 ); and removing the electrode defining layer  12  (as shown in  FIG. 6 ).  
         [0006]     Accordingly, the conductive material is formed by conventional chemical vapor-phase deposition (CVD), physical vapor-phase deposition (PVD) or sputtering so that it has difficulty being connected to other materials such as metal wires for module integration. Meanwhile, the conductive material thus formed cannot be deposited on a flexible substrate due to a mismatched interface between the conductive material (mostly, metal) and polymer. Moreover, the aforementioned process is relatively complicated and costly.  
         [0007]     Therefore, to overcome the aforementioned shortcomings, there is need in providing an electrode and a method for forming the electrode so as to reduce the cost, simplify the process, and make it feasible to form on a flexible substrate at a low temperature the electrode able to be connected to other materials such as metal wires.  
       SUMMARY OF THE INVENTION  
       [0008]     It is a primary object of the present invention to provide an electrode and a method for forming the electrode so as to reduce the cost, simplify the process, and make it feasible to form on a flexible substrate at a low temperature the electrode able to be connected to other materials such as metal wires.  
         [0009]     In order to achieve the foregoing object, the present invention provides a method for forming an electrode, the method comprising steps of: providing a substrate; providing a solution including a solvent and a plurality of metal particles on the substrate; removing the solvent; and making the plurality of metal particles adhere to the substrate.  
         [0010]     Preferably, the plurality of metal particles are bonded with the substrate by chemical bonding.  
         [0011]     Preferably, the substrate is formed of a recrystallizable material.  
         [0012]     Preferably, the recrystallizable material is a conductive polymer material.  
         [0013]     Preferably, the substrate is a flexible substrate.  
         [0014]     Preferably, the solvent comprises methyl benzene, phenol or aldehyde.  
         [0015]     Preferably, the plurality of metal particles comprise nickel (Ni), tin (Sn), silver (Ag) or gold (Au).  
         [0016]     Preferably, the solution is provided on the substrate by spin coating, ink-jet printing, screen printing or imprinting.  
         [0017]     Preferably, the method further comprises a step of: electrically coupling the substrate to a circuit device.  
         [0018]     Preferably, the method further comprises a step of: providing a thermal sensitive polymer material on the substrate.  
         [0019]     The present invention further provides an electrode, comprising: a substrate; and a plurality of metal particles adhering to the substrate.  
         [0020]     Preferably, the plurality of metal particles are bonded with the substrate by chemical bonding.  
         [0021]     Preferably, the substrate is formed of a recrystallizable material.  
         [0022]     Preferably, the recrystallizable material is a conductive polymer material.  
         [0023]     Preferably, the substrate is a flexible substrate.  
         [0024]     Preferably, the plurality of metal particles comprise nickel (Ni), tin (Sn), silver (Ag) or gold (Au).  
         [0025]     Preferably, the plurality of metal particles adhere to the substrate by means of providing a solution comprising a solvent and the plurality of metal particles on the substrate.  
         [0026]     Preferably, the solvent comprises methyl benzene, phenol or aldehyde.  
         [0027]     Preferably, the solution is provided on the substrate by spin coating, ink-jet printing, screen printing or imprinting.  
         [0028]     Preferably, the electrode further comprises: a thermal sensitive polymer material on the substrate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]     The objects, spirits and advantages of the preferred embodiments of the present invention will be readily understood by the accompanying drawings and detailed descriptions, wherein:  
         [0030]      FIG. 1  to  FIG. 6  are schematic diagrams showing a conventional method for forming an electrode in the prior art;  
         [0031]      FIG. 7  is a schematic diagram showing a substrate and a solution;  
         [0032]      FIG. 8  is a schematic diagram showing an electrode according to the present invention;  
         [0033]      FIG. 9  is a flow chart showing a method for forming an electrode according to a first embodiment of the present invention; and  
         [0034]      FIG. 10  is a flow chart showing a method for forming an electrode according to a second embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0035]     The present invention providing an electrode and a method for forming the electrode can be exemplified by the preferred embodiments as described hereinafter.  
         [0036]     Please refer to  FIG. 7 , which is a schematic diagram showing a substrate and a solution. In one embodiment, the substrate  71  is a flexible substrate. Preferably, the substrate  71  is formed of a recrystallizable material such as a conductive polymer material. The solution comprises a solvent  72  and a plurality of metal particles  73 . Preferably, the solvent  72  is an organic solvent comprising methyl benzene, phenol or aldehyde. The plurality of metal particles  73  comprise nickel (Ni), tin (Sn), silver (Ag) or gold (Au).  
         [0037]      FIG. 8  is a schematic diagram showing an electrode according to the present invention. As the solvent  72  is provided on the substrate  71  by spin coating, ink-jet printing, screen printing or imprinting, the coated region (not shown) on the substrate  71  is dissolved to recrystallize. Accordingly, the plurality of metal particles  73  adhere to the substrate  71  by means of being introduced into the recrystallized region. A conductive region is thus formed as an electrode on the substrate  71 . Alternatively, the conductive region can be defined on the substrate  71  using photo-lithography. Afterwards, the substrate  71  can be electrically coupled to a circuit device (not shown). Furthermore, a thermal sensitive polymer material (not shown) can also be provided on the substrate  71  so that the substrate  71  provides heat conductivity and thermal conductivity.  
         [0038]      FIG. 9  is a flow chart showing a method for forming an electrode according to a first embodiment of the present invention. In Step  91 , a substrate is provided. In the present embodiment, the substrate is a flexible substrate. Preferably, the substrate is formed of a recrystallizable material such as a conductive polymer material.  
         [0039]     In Step  92 , a solution comprising a solvent and a plurality of metal particles is provided on the substrate. In the present embodiment, the solvent comprises methyl benzene, phenol or aldehyde. Preferably, the plurality of metal particles comprise nickel (Ni), tin (Sn), silver (Ag) or gold (Au).  
         [0040]     Then, the solvent is heated or air-dried to be removed from the substrate, as described in Step  93 .  
         [0041]     In Step  94 , the metal particles adhere to the substrate.  
         [0042]     More particularly, since the substrate is dissolvable using a solvent, the metal particles in the dissolved region of the substrate can be introduced into the substrate during recrystallization. Consequently, the metal particles are bonded with the substrate by chemical bonding.  
         [0043]     The electrode of the present invention is thus formed. The method of the present invention further comprises a Step  95  of electrically coupling the substrate to a circuit device so that the substrate is used as an electrode.  
         [0044]     Furthermore,  FIG. 10  is a flow chart showing a method for forming an electrode according to a second embodiment of the present invention. Similarly, In Step  91 , a substrate is provided. In the present embodiment, the substrate is a flexible substrate. Preferably, the substrate is formed of a recrystallizable material such as a conductive polymer material.  
         [0045]     In Step  92 , a solution comprising a solvent and a plurality of metal particles is provided on the substrate. In the present embodiment, the solvent comprises methyl benzene, phenol or aldehyde. Preferably, the plurality of metal particles comprise nickel (Ni), tin (Sn), silver (Ag) or gold (Au).  
         [0046]     Then, the solvent is heated or air-dried to be removed from the substrate, as described in Step  93 .  
         [0047]     In Step  94 , the metal particles adhere to the substrate.  
         [0048]     More particularly, since the substrate is dissolvable using a solvent, the metal particles in the dissolved region of the substrate can be introduced into the substrate during recrystallization. Consequently, the metal particles are bonded with the substrate by chemical bonding.  
         [0049]     The electrode of the present invention is thus formed. The method of the present invention further comprises a Step  96  of providing a thermal sensitive polymer material on the substrate so that the substrate is used as a sensor device. In other words, the substrate can provide various characteristics such as electric conductivity, thermal conductivity, light conductivity, magnetism permeability, or EMI immunity using different polymer materials.  
         [0050]     Compared to the method of the present invention, the conventional method requires electrode pattern defining, photo-lithography, metallization using CVD, PVD or sputtering, and chemical-mechanical polishing (CMP).  
         [0051]     Therefore, the method of the present invention has advantages in:  
         [0052]     (1) wide applications for both rigid substrates and flexible substrate;  
         [0053]     (2) lower temperature and lower cost without conventional CVD, PVD or sputtering;  
         [0054]     (3) feasibility to form on a flexible substrate an electrode able to be connected to other materials such as metal wires and devices.  
         [0055]     According to the above discussion, it is apparent that the present invention discloses an electrode and a method for forming the electrode so as to reduce the cost, simplify the process, and make it feasible to form on a flexible substrate at a low temperature the electrode able to be connected to other materials such as metal wires. Therefore, the present invention is novel, useful and non-obvious.  
         [0056]     Although this invention has been disclosed and illustrated with reference to particular embodiments, the principles involved are susceptible for use in numerous other embodiments that will be apparent to persons skilled in the art. This invention is, therefore, to be limited only as indicated by the scope of the appended claims.