Abstract:
A method for producing an ITO transparent substrate with a high resistance at a low-temperature sputtering process is provided for mass production. The method is characterized by: a film of ITO mixed with metallic-oxide target and coated with multiple layers provides a transparent capacity. The film can be produced via a production line and further heated and annealed for stabilizing the high resistance thereof.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an ITO transparent substrate with a high resistance at a low-temperature sputtering process and a method for producing the same, and particularly relates to a layer of metal oxide doped ITO, and mated with multiple depositing layers that overlap each other.  
         [0003]     2. Description of the Related Art  
         [0004]     In the optoelectronical raw material industry, ITO (layer) with high resistance is an important raw material and the process of producing the ITO layer is a key component of producing a panel. As the raw material industry is becoming more and more important, the requirements of high yield, precise control, low cost, and fast fabrication method for the row material production are increasing in importance also. The high-resistance ITO layer can be applied to touchpanel techniques, such as capacitive touchpanels and resistive touchpanels.  
         [0005]     As is commonly known, the ITO layer plays a major role in touchpanels. For example, in resistive touchpanels, an ITO layer with high resistance replaces conductive glass or plastics with low resistance. In regard to capacitive touchpanels, an ITO layer with high resistance is necessary thereto. Therefore, the ITO layer with high light transmittance and high resistance are preferable to the touchpanel applications.  
         [0006]     As showed in  FIGS. 1A and 1C , a transmission layer  22   a  of a resistive touchpanel is illustrated. When the transmission layer  22   a  is produced via the sputtering process by the pure ITO target to form the high resistance, poor stability product is obtained. For a high classic and high definition product, the characteristic resistance and the stability of ITO film are both required to be high. For example, when a touch panel  13   a  contacts the resistive screen  12   a,  a pressure is forced near a spacer  26   a.  The transmission layer  22   a  of a contact layer  34   a  disposed over a glass layer  20   a  forces the glass layer  20   a  thereby, so that a location signal of a panel  24   a  is transmitted via a connection device  32   a  of a separation layer  30   a.  That means the conventional process stability is bad and specific resistances of the resistive touchpanel produced thereby are not easily achieved.  
         [0007]     Reference is made to  FIGS. 1B and 1D , in which a capacitive touchpanel is illustrated. The capacitive touch panel is coated with transparent electrodes that store electrical charges. When a panel  14   a  is touched by a finger  21   a,  a small amount of charge is drawn to the point of contact. Circuits located at each corner of the panel  14   a  measure the charge and send the data information to a controller.  
         [0008]     A cross-sectional profile of the capacitive touchpanel is shown in  FIG. 1D . A transmission layer  16   a  is coated on a glass  17   a  and further covered by an electrode layer  18   a  and a protection layer  19   a  sequentially. A conduction layer  15   a  is used to shield against electromagnetic waves. The design and the structure of the capacitive touchpanel can be complicated with high associated costs.  
         [0009]     Therefore, an ITO transparent substrate being generally multi-layered that has a high resistance produced via a low-temperature sputtering process that can be formed quickly and reliably is greatly desired by the panel producing industry. In particular, a substrate made of polymer materials, (such as PMMA,) or glass, is needed in order to provide the desired stable characteristics.  
       SUMMARY OF THE INVENTION  
       [0010]     An ITO transparent substrate with a high resistance at a low-temperature sputtering process and a method for producing the same are provided. The substrate has a stable nature and is easily manufactured. Conventional fabrication equipment, with some alterations and improvements can be used to produce the substrate of the present invention.  
         [0011]     The ITO transparent substrate with a high, stable resistance such as a resistive touchpanel of above 800 ohm/sq or a capacitive touchpanel of above 1500 ohm/sq at a low-temperature sputtering process is provided. The method includes steps of providing some refraction layers on a substrate base and further covered by a metallic oxide doped ITO top layer in order to be highly transparent and anti-reflective. A production line can be applied to the conventional manufacturing process, which is free of complex methods and procedures.  
         [0012]     The method for producing an ITO transparent substrate includes: providing a transparent substrate base; sputtering the transparent substrate base with plasma, which is composed of ITO target mixed with metallic oxide target in order to produce at least one film. The ITO transparent substrate includes a transparent substrate base, and at least one film with metallic oxide doped ITO on the substrate base.  
         [0013]     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. Other advantages and features of the invention will be apparent from the following description, drawings and claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:  
         [0015]      FIG. 1A  is a perspective view of a conventional resistive touchpanel;  
         [0016]      FIG. 1B  is a perspective view of a conventional capacitive touchpanel;  
         [0017]      FIG. 1C  is a cross-sectional profile of the conventional resistive touchpanel;  
         [0018]      FIG. 1D  is a cross-sectional profile of the conventional capacitive touchpanel;  
         [0019]      FIG. 2  is a sketch of an ITO substrate line according to the present invention;  
         [0020]      FIG. 3A  is a perspective view of a first embodiment of the ITO substrate according to the present invention;  
         [0021]      FIG. 3B  is a perspective view of a second embodiment of the ITO substrate according to the present invention; and  
         [0022]      FIG. 4  is a flow chart according to the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0023]     Reference is made to  FIGS. 2, 3A  and  3 B, which show a glass treated as a substrate being adapted for a conventional simple manufacturing process for a production line. In a first embodiment, a transparent substrate base  10  is sputtered with plasma  40 . Referring to  FIG. 2 , a sketch of the ITO substrate according to the present invention, the substrate base  10  in its initial condition is sputtered with at least one film of metallic oxide  20  or non-metallic oxide  30  (as mentioned in step S 103  in  FIG. 4 ). Furthermore, the substrate base  10  is processed with plasma  40 . After the plasma  40 , the substrate base  10  is processed in a predetermined auxiliary process. The substrate base  10  is heated above 300° C. (a predetermined temperature) for 30 minutes (a first predetermined period) and is further cured by an annealing process at 150˜200° C. (a predetermined range at a low temperature) for 30 minutes (a second predetermined period) in order to produce a finished product. The curing that is produced via the annealing process is described in greater detail in S 107  and illustrated in  FIG. 4 .  
         [0024]     In a second embodiment, the substrate base  10  is heated above 300° C. (the predetermined temperature) but the curing process is omitted to produce a stable resistance thereof. In addition, the substrate base  10  can be PMMA or other plastic materials (such as polymer materials) but with lower heated temperature.  
         [0025]     Furthermore, at least one silicon-oxide layer is piled with the film  24 , which is produced by sputtered with ITO mixed with metallic-oxide (such as Nb 2 O 5 ) target, shown in  FIGS. 3A and 3B . Naturally, a total quantity of the layers on the substrate base  10  may be 3 to 5 in order to be a multi-layered substrate. The present embodiments show the arrangement of the layers of the substrate is flexible.  
         [0026]      FIGS. 3A and 3B  illustrate a first embodiment of the layers, including a refraction layer with a high refraction index  22 , a refraction layer with low refraction index  32 , another refraction layer with high refraction index  22 , another refraction layer with low refraction index  32 , and further covered with a metallic oxide doped ITO layer  24  in  FIG. 3A . A second embodiment of the layers, can include a refraction layer with high refraction index  22 , a refraction layer with low refraction index  32 , and a metallic oxide doped ITO layer  24  as is illustrated in  FIG. 3B . The refraction layer with high refraction index  22  is made of metallic oxide  20 , but the refraction layer with low refraction index  32  is made of non-metallic oxide  30 .  
         [0027]     With reference in  FIG. 4 , the method includes steps of: providing the substrate base  10  (step S 101 ), coating multiple layers on the base  10  (step S 103 ), sputtering the substrate base  10  with plasma  40  that is a mixture of ITO and metallic oxide (Nb 2 O 5 ) (step S 105 ), and further heating and annealing the substrate base  10 .  
         [0028]     The mixed plasma is generated by a dual gun sputtering system or a single mixed gun sputtering system. In addition, the substrate base  10  can be processed in workstations continuously connected to one another in order to guarantee a delay time controlled for a predetermined range. The transparent substrate base  10  is made of a polymer material or a glass material. Furthermore, the steps mentioned are implemented in a clean room. The transparent substrate base  10  is transited between workstations via a conveyer belt or an automatic trolley. Experimentally, these embodiments according to the present invention can provide stable resistance.  
         [0029]     There are some advantages to the present invention:  
         [0030]     1. The amount of Nb 2 O 5  in ITO can vary the resistance thereof.  
         [0031]     2. ITO with Nb 2 O 5  can be further processed with another material to achieve high transmission.  
         [0032]     3. The resistance thereof is more stable than that of the layer made only of ITO.  
         [0033]     4. Not only Nb 2 O 5  but also non-conductive metallic oxide material or non-metallic oxide material can be adapted thereto.  
         [0034]     Although the present invention has been described with reference to the preferred embodiments thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.