Abstract:
A Cu-interconnection etching device includes an etching liquid tank containing therein an etching liquid that is a hydrogen peroxide based solution, a first concentration monitoring device receiving the etching liquid from the etching liquid tank and measuring a copper ion concentration of the etching liquid. The etching liquid is supplied through a filter assembly that filters off copper ions contained in the etching liquid so as to provide a filtered etching liquid. The filter etching liquid is supplied through a second concentration monitoring device that measures a copper ion concentration of the filtered etching liquid and conducts the filtered etching liquid back to the etching liquid tank. A variation between the measurements of the first and second concentration monitoring devices is used to control the operation of the filter assembly in order to maintain a proper level of copper ion concentration in the etching liquid.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a divisional application of co-pending U.S. patent application Ser. No. 14/428,980, filed on Mar. 18, 2015. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to the field of display technology, and more particularly to a method of improving lifetime of etching liquid and yield in Cu-interconnection process and a Cu-interconnection etching device. 
         [0004]    2. The Related Arts 
         [0005]    With the development of the display technology, flat panel devices, such as liquid crystal displays (LCDs), possess advantages of high image quality, power saving, thin body, and wide application scope. Thus, it has been widely applied in various consumer electrical products, such as mobile phones, televisions, personal digital assistants, digital cameras, notebook computers, and laptop computers, and become the major display devices in the market. 
         [0006]    Generally, a liquid crystal panel comprises a color filter substrate, an array substrate, liquid crystal sandwiched between the color filter substrate and the array substrate, and sealant. Metal lines are formed on the array substrate. The resistance and RC delay due to the resistance of the metal lines have a great influence on the performance of the liquid crystal display panel, and this is particularly obvious for large scale and high resolution liquid crystal panels. The array substrates of conventional liquid crystal panels commonly utilize aluminum (Al)-interconnection. The Al-interconnection has higher electrical resistivity and the RC delay coming along therewith is also larger, making it hard to be applied to large scale and high resolution liquid crystal display panels. 
         [0007]    Compared with the Al-interconnection, Cu-interconnection possesses lower electrical resistivity and the RC delay coming along therewith is smaller, making it suit the needs for constant size growing up and high resolution of the liquid crystal display panels. However, in the conventional Cu-interconnection process, a hydrogen peroxide (H 2 O 2 ) based solution is commonly utilized as an etching liquid. Such an etching liquid suffers certain problems. For example, the concentration of copper ions in the etching liquid would increase with an increased number of substrates etched with such a liquid and H 2 O 2  undergoes a chemical change of increased speed of decomposition with the following reaction process: H 2 O 2 -→H 2 +O 2  with the presence of Cu ions. Furthermore, with the progress of the Cu-interconnection etching process, the copper ion concentration of the etching liquid keeps increasing. The decomposition rate of the H 2 O 2  gets faster and faster. When the copper ion concentration exceeds 6000 ppm, the decomposition rate of the H 2 O 2  will rapidly increase and generates a mass of gas, which can cause explosion of the apparatus. Therefore, as the copper ion concentration exceeds 6000 ppm, new etching liquid has to be provided and used and this greatly restricts the usage lifetime of the etching liquid and increases the production cost. Besides, with the increase of the copper ion concentration in the etching liquid, the etching rate of the etching liquid will also change. Thus, the stability and the yield of products are influenced. 
       SUMMARY OF THE INVENTION 
       [0008]    An objective of the present invention is to provide a method of improving lifetime of etching liquid and yield in a Cu-interconnection process, capable of adjusting the copper ion concentration of the etching liquid to promote the usage lifetime of the etching liquid and reduce the production cost for raising the stability and yield of the Cu-interconnection production. 
         [0009]    Another objective of the present invention is to provide a Cu-interconnection etching device, capable of adjusting the copper ion concentration of an etching liquid to promote the usage lifetime of the etching liquid and reduce the production cost for raising the stability and yield of the Cu-interconnection production. 
         [0010]    For realizing the aforesaid objectives, the present invention first provides a method of improving lifetime of etching liquid and yield in Cu-interconnection process, comprising the following steps: 
         [0011]    step  1 , providing an etching spray rising tank and an etching liquid tank connected to the etching spray rising tank, wherein the etching liquid tank contains an etching liquid; 
         [0012]    step  2 , employing a first concentration monitoring device to measure a copper ion concentration of the etching liquid in the etching liquid tank, and employing a filter to perform copper ion filtering to the etching liquid in the etching liquid tank; 
         [0013]    step  3 , employing a second concentration monitoring device to measure a copper ion concentration of the etching liquid after filtering in step  2 , and controlling an amount of the filters employed to perform copper ion filtering in step  2  and reflowing the etching liquid after filtering to the etching liquid tank. 
         [0014]    The etching liquid employed in step  1  is a hydrogen peroxide based etching liquid. 
         [0015]    The filter in step  2  further comprises one or more reverse osmosis membranes connected in series for filtering copper ions, one or more filter fabrics connected in series for filtering copper ions or several reverse osmosis membranes and filter fabrics connected in series for filtering copper ions. 
         [0016]    The number of specific ones of the filters employed to perform copper ion filtering is controlled to be activated by a control device according to a variation of the copper ion concentration of the etching liquid measured by the first concentration monitoring device and the second concentration monitoring device and the filters are connected in series. 
         [0017]    The etching method of Cu-interconnection is employed for manufacturing an array substrate utilizing the Cu-interconnection. The first concentration monitoring device of step  2  further measures a hydrogen peroxide concentration and an additive concentration of the etching liquid. The second concentration monitoring device of step  3  further measures a hydrogen peroxide concentration and an additive concentration of the etching liquid. 
         [0018]    The present invention also provides a Cu-interconnection etching device, which comprises an etching spray rising tank, an etching liquid tank connected to the etching spray rising tank, a liquid pump connected to the etching liquid tank, and one or more filters connected to the liquid pump. The filter is connected to the etching liquid tank and comprises a first concentration monitoring device for monitoring a copper ion concentration of the etching liquid in the etching liquid tank. 
         [0019]    The filter is employed to perform copper ion filtering to the etching liquid to reduce the copper ion concentration of the etching liquid. 
         [0020]    The first concentration monitoring device is located in the etching liquid tank, between the etching liquid tank and the liquid pump, or between the liquid pump and the filter. 
         [0021]    The Cu-interconnection etching device further comprises a second concentration monitoring device, and the second concentration monitoring device is located between the filter and the etching liquid tank and employed to monitor a copper ion concentration of the etching liquid after filtering. The first concentration monitoring device further monitors a hydrogen peroxide concentration and an additive concentration of the etching liquid in the etching liquid tank. The second concentration monitoring device further monitors a hydrogen peroxide concentration and an additive concentration of the etching liquid after filtering. 
         [0022]    The number of the filters involved is plural and they are connected in series. The Cu-interconnection etching device further comprises a control device, and the control device is electrically connected to the first concentration monitoring device, the second concentration monitoring device and each of the filters, to control whether each of the filter performs copper ion filtering or not according to concentration monitoring result. 
         [0023]    Each of filters further comprises one or more reverse osmosis membranes connected in series for filtering copper ions, one or more filter fabrics connected in series for filtering copper ions, or several reverse osmosis membranes and filter fabrics connected in series for filtering copper ions. 
         [0024]    The Cu-interconnection etching device is employed for a process of an array substrate utilizing the Cu-interconnection. 
         [0025]    The present invention further provides a method of improving lifetime of etching liquid and yield in Cu-interconnection process, comprising the following steps: 
         [0026]    step  1 , providing an etching spray rising tank and an etching liquid tank connected to the etching spray rising tank, wherein the etching liquid tank contains etching liquid; 
         [0027]    step  2 , employing a first concentration monitoring device to measure a copper ion concentration of the etching liquid in the etching liquid tank, and employing a filter to perform copper ion filtering to the etching liquid in the etching liquid tank; 
         [0028]    step  3 , employing a second concentration monitoring device to measure a copper ion concentration of the etching liquid after filtering in step  2 , and controlling an amount of the filters employed in step  2  and reflowing the etching liquid after filtering to the etching liquid tank; 
         [0029]    wherein the etching liquid employed in step  1  is a hydrogen peroxide based etching liquid; 
         [0030]    wherein the filter of step  2  further comprises one or more reverse osmosis membranes connected in series for filtering copper ions, one or more filter fabrics connected in series for filtering copper ions, or several reverse osmosis membranes and filter fabrics connected in series for filtering copper ions. 
         [0031]    The benefits of the present invention are as follows. The present invention provides a method of improving lifetime of etching liquid and yield in Cu-interconnection process and a Cu-interconnection etching device. By adding filters in a recycle process of the etching liquid to constantly filter off copper ions of the etching liquid and reflowing the etching liquid after filtering to the etching liquid tank for cyclic utilization, the copper ion concentration of the etching liquid can be reduced to promote the usage lifetime of the etching liquid and reduce the production cost for raising the stability and yield of the Cu-interconnection production. 
         [0032]    In order to better understand the characteristics and technical aspect of the invention, please refer to the following detailed description of the present invention is concerned with the diagrams, however, provide reference to the accompanying drawings and description only and is not intended to be limiting of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    The technical solution and the beneficial effects of the present invention are best understood from the following detailed description with reference to the accompanying figures and embodiments. 
           [0034]    In the drawings: 
           [0035]      FIG. 1  is a flowchart of an etching method of Cu-interconnection according to the present invention; and 
           [0036]      FIG. 2  is a structural diagram of an etching device of Cu-interconnection according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0037]    For better explaining the technical solution and the effect of the present invention, the present invention will be further described in detail with the accompanying drawings and the specific embodiments. 
         [0038]    Referring to  FIG. 1  in conjunction with  FIG. 2 , the present invention first provides a method of improving lifetime of etching liquid and yield in Cu-interconnection process, which comprises the following steps: 
         [0039]    step  1 , providing an etching spray rising tank  1  and an etching liquid tank  2  connected to the etching spray rising tank  1 , wherein the etching liquid tank  2  contains an etching liquid. 
         [0040]    Specifically, the etching liquid employed in the step  1  is a hydrogen peroxide based etching liquid. 
         [0041]    step  2 , employing a first concentration monitoring device  4  to measure a copper ion concentration of the etching liquid in the etching liquid tank  2 , and employing a filter  5  to perform copper ion filtering to the etching liquid in the etching liquid tank  2 . 
         [0042]    Specifically, the filter  5  of step  2  further comprises one or more reverse osmosis membranes connected in series for filtering copper ions, one or more filter fabrics connected in series for filtering copper ions, or several reverse osmosis membranes and filter fabrics connected in series for filtering copper ions copper ions. In step  2 , several filters  5  can be utilized, and the filters  5  are connected in series. Furthermore, a method of setting a cyclic tank can be employed to collect the copper ions after filtering for recycling of the copper ions. 
         [0043]    The first concentration monitoring device  4  can be directly located in the etching liquid tank  2 , between the etching liquid tank  2  and the liquid pump  3 , and respectively connected to the etching liquid tank  2  and the liquid pump  3 , or between the liquid pump  3  and the filter  5 , and respectively connected to the liquid pump  3  and the filter  5 , and can be employed to monitor the copper ion concentration in the etching liquid tank  2  in order to ensure a normal use of the etching liquid in the etching liquid tank  2 . Besides, the first concentration monitoring device  4  further measures a hydrogen peroxide concentration and an additive concentration of the etching liquid for adding the additive in time to ensure the quality of the etching liquid and the etching result of the Cu-interconnection. 
         [0044]    step  3 , employing a second concentration monitoring device to measure a copper ion concentration of the etching liquid after filtering in step  2 , and controlling a number of specific ones of the filters  5  to perform copper ion filtering in step  2  and reflowing the etching liquid after filtering to the etching liquid tank  2 . 
         [0045]    Specifically, in the step  3 , the number of the specific ones of the filters  5  employed to perform copper ion filtering is controlled to be activated by a control device according to a variation of the copper ion concentration of the etching liquid measured by the first concentration monitoring device  4  and the second concentration monitoring device  6 . If the copper ion concentration of the etching liquid after filtering is lower than a demanded copper ion concentration of the etching liquid, the number of the filters  5  employed to perform copper ion filtering is decreased. If the copper ion concentration of the etching liquid after filtering is higher than the demanded copper ion concentration of the etching liquid, the number of the filters  5  employed to perform copper ion filtering is increased. Furthermore, the program can be set in the control device to realize the automatic adjustment to maintain the copper ion concentration at the best stable value. 
         [0046]    The step  3  further comprises a step of measuring a hydrogen peroxide concentration and an additive concentration of the etching liquid after filtering with the filter  5  by a second concentration monitoring device  6 , wherein the copper ion concentration of the etching liquid after filtering is monitored to ensure the filtering result and the hydrogen peroxide concentration and the additive concentration of the etching liquid are monitored for adding the additive in time to ensure the quality of the etching liquid and the etching result of the Cu-interconnection when the filter causes the additive concentration loss. 
         [0047]    At last, the Cu-interconnection etching method is employed for manufacturing an array substrate utilizing the Cu-interconnection. 
         [0048]    Referring to  FIG. 2 , the present invention also provides a Cu-interconnection etching device, which comprises an etching spray rising tank  1 , an etching liquid tank  2  connected to the etching spray rising tank  1 , a liquid pump  3  connected to the etching liquid tank  2 , and one or more filters  5  connected to the liquid pump  3 . The filter(s)  5  are connected to the etching liquid tank  2  and further comprise a first concentration monitoring device  4 , which is employed to monitor a copper ion concentration of the etching liquid in the etching liquid tank  2 . The filter(s)  5  are employed to perform copper ion filtering to the etching liquid to reduce the copper ion concentration of the etching liquid. 
         [0049]    The first concentration monitoring device  4  can be directly located in the etching liquid tank  2 , between the etching liquid tank  2  and the liquid pump  3 , and respectively connected to the etching liquid tank  2  and the liquid pump  3 , or between the liquid pump  3  and the filter  5 , and respectively connected to the liquid pump  3  and the filter  5 , and employed to monitor the copper ion concentration in the etching liquid tank  2  in order to ensure a normal use of the etching liquid in the etching liquid tank  2 . Besides, the first concentration monitoring device  4  further measures a hydrogen peroxide concentration and an additive concentration of the etching liquid for adding the additive in time to ensure the quality of the etching liquid and the etching result of the Cu-interconnection. 
         [0050]    Particularly, the filter  5  is employed to filter the copper ions of the etching liquid to reduce the copper ion concentration of the etching liquid. The filter  5  can be any device that filters off copper ions. Specifically, the filter  5  can comprise one or more reverse osmosis membranes connected in series for filtering copper ions to realize rapid copper ion filtering. The reverse osmosis membranes can be regularly replaced according to the usage efficiency to ensure the filtering quality. Moreover, the filter  5  can comprise one or more filter fabrics connected in series for filtering copper ions. The filter  5  also can comprise several reverse osmosis membranes and filter fabrics connected in series for filtering copper ions. Besides, the filter  5  can further comprise a cyclic tank (not shown), which is employed to collect the filtered copper ions after filtering for recycling of the copper ions. 
         [0051]    The Cu-interconnection etching device further comprises a second concentration monitoring device  6 , and the second concentration monitoring device  6  is connected to the filter  5  and the etching liquid tank  2  to monitor the copper ion concentration of the etching liquid after filtering to ensure the filtering result. Meanwhile, the second concentration monitoring device  6  can further monitor a hydrogen peroxide concentration and an additive concentration of the etching liquid for adding the additive in time according to the monitor data when the filter  5  causes the additive concentration loss. 
         [0052]    Besides, the number of the filters  5  can be increased or decreased according to the copper ion concentration demand of the etching process. Preferably, the Cu-interconnection etching device further comprises a control device, and the control device is electrically connected to the first concentration monitoring device  4 , the second concentration monitoring device  6 , and each filter  5  to control whether each filter  5  performs copper ion filtering or not according to concentration monitoring result. Specifically, the control device obtains the copper ion concentration data of the etching liquid before filtering from the first concentration monitoring device  4 , and obtains the copper ion concentration data of the etching liquid after filtering from the second concentration monitoring device  6 , and monitors whether the filtering result reaches a target or not according to a variation of the copper ion concentration of the etching liquid before and after filtering and the copper ion concentration data of the etching liquid demanded by the etching process. If the copper ion concentration of the etching liquid after filtering is lower than the demanded copper ion concentration of the etching liquid, the number of the filters  5  employed to perform copper ion filtering is decreased. If the copper ion concentration of the etching liquid after filtering is higher than the demanded copper ion concentration of the etching liquid, the number of the filters  5  employed to perform copper ion filtering is increased. Thus, real-time adjustment of the copper ion concentration of the etching liquid can be achieved. Furthermore, the program can be set in the control device to realize the automatic adjustment to maintain the copper ion concentration at the best stable value. 
         [0053]    At last, the Cu-interconnection etching device is employed for a process of an array substrate utilizing the Cu-interconnection. 
         [0054]    In conclusion, the present invention provides a method of improving lifetime of etching liquid and yield in Cu-interconnection process and a Cu-interconnection etching device. By adding filters in a recycle process of an etching liquid to constantly filter copper ions of the etching liquid and reflowing the etching liquid after filtering to the etching liquid tank for cyclic utilization, the copper ion concentration of the etching liquid can be reduced to promote the usage lifetime of the etching liquid and reduce the production cost for raising the stability and product yield of the Cu-interconnection production. 
         [0055]    The above provides only specific embodiments of the present invention, and the scope of the present invention is not limited to such embodiments. Those skilled in the art would appreciate change or replacement, which can be easily derived from the above, should be covered by a protection scope of the invention. Thus, the protection scope of the invention should be defined by the appended claims.