Patent Publication Number: US-2019189830-A1

Title: Sputter coating device and method for solar cell

Description:
CROSS REFERENCE 
     This application is based upon and claims priority under 35 U.S.C. § 119(a)-(d) or 35 U.S.C. § 365(b) to Chinese Patent Application No. 201721752635.2, filed on Dec. 14, 2017, the entire contents thereof are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to the art of solar cell processing, in particular to a sputter coating device and method for a solar cell. 
     BACKGROUND 
     The flexible substrate copper indium gallium selenide (CIGS) thin film solar cell has the advantages of light weight, strong radiation resistance, and good stability. Combined with roll-to-roll technology, it is suitable for large-scale production and can significantly reduce material costs and manufacturing costs. 
     The window layer is not only the core part of the CIGS solar cell heterojunction n-type region, but also the main channel of the battery power output. The window layer is the film layer sputtered on the substrate, and the uniformity of the window layer is particularly important for the battery conversion efficiency and product yield. In the actual industrial production process, due to the characteristics of the target material, the distribution of the sputtering gas, and the distribution of the magnetic field in the target, the uniformity of the thickness of the prepared window layer is not ideal. By measuring the thickness of the window layer on the coated substrate, it may be seen that the middle part of the film layer is thicker, the upper and lower sides are thinner, and the uniformity is greatly deviated, which cannot meet the actual needs of industrial production. 
     SUMMARY 
     According to one aspect of the present disclosure, a sputter coating device for a solar cell is used for sputtering a target to a substrate, wherein the sputter coating device for a solar cell comprises a blocking unit between the target and the substrate, and the orthographic projection of the blocking unit on the substrate partially coincides with the orthographic projection of the target on the substrate. 
     According to an embodiment of the present disclosure, the orthographic projection of the blocking unit on the target is located in the middle of the target. 
     According to an embodiment of the present disclosure, the length of the blocking unit accounts for 50% to 75% of the length of the target. 
     According to an embodiment of the present disclosure, four targets are provided and arranged in-line, and the blocking unit is arranged at the target at the end in the arrangement direction. 
     According to an embodiment of the present disclosure, the sputter coating device for a solar cell further includes a fixing device for fixing the target. 
     According to an embodiment of the present disclosure, the fixing device is a target chamber, the target is fixed in the target chamber, an opening is provided on the side of the target chamber near the substrate, and the blocking unit is fixed on the side of the target chamber where the opening is provided. 
     According to an embodiment of the present disclosure, the blocking unit is detachably fixed on the target chamber and covers the middle of the opening. 
     According to an embodiment of the present disclosure, the target chamber is provided with an accommodating slot, and the target is fixed to the accommodating slot, and the opening communicates with the accommodating slot. 
     According to an embodiment of the present disclosure, the width of the blocking unit is equal to or greater than the width of the opening, and the length of the blocking unit accounts for 50%-75% of the length of the opening. 
     According to an embodiment of the present disclosure, the blocking unit is a baffle, and an anti-corrosion film layer is disposed on the baffle. 
     According to another aspect of the present disclosure, a sputter coating method for a solar cell is used for sputtering a target to a substrate, wherein the sputter coating method includes: 
     Providing a blocking unit between the target and the substrate, and the orthographic projection of the blocking unit on the substrate partially coincides with the orthographic projection of the target on the substrate. 
     According to an embodiment of the present disclosure, the orthographic projection of the blocking unit on the target is located in the middle of the target. 
     According to an embodiment of the present disclosure, the length of the blocking unit accounts for 50% to 75% of the length of the target. 
     According to an embodiment of the present disclosure, four targets are provided and arranged in-line, and the blocking unit is arranged at the target at the end in the arrangement direction. 
     According to an embodiment of the present disclosure, the sputter coating method for a solar cell further includes providing afixing device for fixing the target. 
     According to an embodiment of the present disclosure, the fixing device is a target chamber, the target is fixed in the target chamber, an opening is provided on the side of the target chamber near the substrate, and the blocking unit is fixed on the side of the target chamber where the opening is provided. 
     According to an embodiment of the present disclosure, the blocking unit is detachably fixed on the target chamber and covers the middle of the opening. 
     According to an embodiment of the present disclosure, the width of the blocking unit is equal to or greater than the width of the opening, and the length of the blocking unit accounts for 50%-75% of the length of the opening. 
     According to an embodiment of the present disclosure, the target chamber is provided with an accommodating slot, and the target is fixed to the accommodating slot, and the opening communicates with the accommodating slot. 
     According to an embodiment of the present disclosure, the blocking unit is a baffle, and an anti-corrosion film layer is disposed on the baffle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of a sputter coating device for a solar cell according to an embodiment of the present disclosure; 
         FIG. 2  is a front view of a sputter coating device for a solar cell according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary, are used to explain the present disclosure only, and not intended to limit the present disclosure. 
     As shown in  FIG. 1 , also referring to  FIG. 2 , an embodiment of the present disclosure provides a sputter coating device for a solar cell is used for sputtering a target to a substrate, wherein the sputter coating device for a solar cell includes a blocking unit  2 . 
     The blocking unit  2  is located between the target  1  and the substrate  3 , and the orthographic projection of the blocking unit  2  on the substrate  3  partially coincides with the orthographic projection of the target  1  on the substrate  3 . 
     In the sputter coating device for a solar cell provided by the present disclosure, by providing a blocking unit  2  between the target  1  and the substrate  3 , a specific part of the target  1  may be blocked by the blocking unit  2 , so that the thickness of the film layer formed by sputtering at the blocked part on the substrate  3  may be reduced, that is, the part of the target  1  corresponding to the thicker part of the film layer previously formed on the substrate  3  is blocked by the blocking unit  2 , so that the thickness of the film layer formed on the substrate  3  by sputtering the blocked part and the non-blocking part tends to be uniform. 
     In the sputter coating device for a solar cell provided by the present disclosure, by flexibly setting the position of the blocking unit  2 , the thickness of the film layer formed by sputtering on the substrate  3  is consistent and the uniformity of the film layer is improved, so as to meet the actual needs of industrial production. 
     In an embodiment, the blocking unit  2  is fixed with respect to the target  1 , and the orthographic projection of the blocking unit  2  on the target  1  is located in the middle of the target  1 . In an embodiment, the blocking unit  2  is disposed close to the target  1 , and faces the middle of the target  1 . In an embodiment, the length of the blocking unit  2  accounts for 50% to 75% of the length of the target  1 . 
     Wherein, in the embodiment of the present disclosure, the blocking unit  2  is disposed close to the target  1 , and it may also not be disposed close to the target  1 , but only the projection is located in the middle of the target  1  so as to block the middle of the target  1 . Generally, the length of the blocking unit  2  accounts for 70% of the length of the target  1 , i.e., 15% at both ends are not blocked, so that the middle part (where the thickness was previously thicker) of the film layer formed on the substrate  3  may be heavily blocked, so that the thickness of the film layer at the part is reduced, and the overall thickness of the film layer is uniform. The shapes of the target  1  and the blocking unit  2  are not limited, as long as the blocking unit  2  may partially block. 
     Optionally, the blocking unit  2  may also be disposed close to the substrate  3 , and the blocking unit  2  faces the middle part of the substrate  3 . In an embodiment, the length of the blocking unit  2  accounts for 50%-75% of the length of the substrate  3 . In the same way, in the embodiment of the present disclosure, the blocking unit  2  may also be disposed close to the substrate  3 , and the purpose of making the overall thickness of the film layer uniform may also be achieved. 
     In the embodiment of the present disclosure, in an embodiment, four targets  1  are provided and arranged in-line, and the blocking unit  2  is arranged at the target  1  at the end in the arrangement direction. In an embodiment, four targets  1  are sequentially arranged in parallel, and the blocking unit  2  is arranged at the fourth target  1  or the first target  1 . Blocking one of the four targets  1  may generally make the thickness of the sputtered film layer uniform. Obviously, those skilled in the art understand that the number of targets  1 , the number of blocked targets  1 , and the number of blocking units  2  are not limited, and may be flexibly set according to actual conditions. 
     In an embodiment, the sputter coating device for a solar cell further includes a fixing device for fixing the target  1 , the fixing device, for example, is a target chamber. In an embodiment, an accommodating slot for accommodating the target  1  is provided in the target chamber  4 , and the side of the target chamber near the substrate  3  is provided with an opening  40  communicating with the accommodating slot. The target  1  is sputtered to the substrate  3  through the opening  40 . In an embodiment, the blocking unit  2  is fixed on the side of the target chamber  4  where the opening  40  is provided, and the blocking unit  2  covers the middle of the opening  40 . In an embodiment, the blocking unit  2  is detachably fixed to the target chamber  4  by a detachable connector such as a screw  5 . In an embodiment, the width of the blocking unit  2  is equal to or greater than the width of the opening  40 , and the length of the blocking unit  2  accounts for 50%-75%, such as 55%, 60%, 65%, and 70% of the length of the opening  40 . 
     Wherein, the target  1  has a variety of shapes, such as a cylindrical shape or a cuboid shape, or the like, and correspondingly, an accommodating slot having the same shape is provided in the target chamber  4 , into which the target  1  may be directly inserted. In order to reserve a channel for direct sputtering of the target  1  to the substrate  3 , an opening  40  is formed on the target chamber  4 , and the opening  40  is generally located between the target  1  and the substrate  3 . The width of the opening  40  is less than or equal to the width of the target  1  to prevent the target  1  from leaking out of the opening  40 , and the width of the blocking unit  2  is greater than or equal to the width of the opening  40 , so as to ensure complete blocking of a specific part of the target  1 . Corresponding position on the target chamber  4  is provided with a pin hole, which may cooperate with the screw  5  to fix the blocking unit  2 . 
     In an embodiment, the blocking unit  2  is a baffle, and an anti-corrosion film layer is disposed on the baffle. 
     Wherein, the baffle is 304 austenitic stainless steel, which has extremely strong rust and corrosion resistance, but also excellent plasticity and toughness, and is easy to manufacture. The size and the shielding position of the baffle may be changed according to actual needs so as to achieve a uniform coating of a large area on the substrate  3 . The anti-corrosion layer is generally made of titanium. 
     The sputter coating method for a solar cell according to the present disclosure is used for sputtering a target  1  to a substrate  3 , wherein the sputter coating method includes: 
     Providing a blocking unit  2  between the target  1  and the substrate  3 , and the orthographic projection of the blocking unit  2  on the substrate  3  partially coincides with the orthographic projection of the target  1  on the substrate  3 . The orthographic projection of the blocking unit  2  on the target  1  is located in the middle of the target  1 . The length of the blocking unit  2  accounts for 50% to 75% of the length of the target. In an embodiment, the blocking unit  2  is a baffle, and an anti-corrosion film layer is disposed on the baffle. 
     In an embodiment, the sputter coating method for a solar cell further includes providing a fixing device for fixing the target  1 . 
     In an embodiment, the fixing device is a target chamber  4 , an opening  40  is provided on the side of the target chamber  4  near the substrate  3 , and the blocking unit  2  is fixed on the side of the target chamber  4  where the opening  40  is provided. The target chamber  4  is provided with an accommodating slot, the target  1  is fixed to the accommodating slot, and the opening  40  communicates with the accommodating slot. 
     The blocking unit  2  is detachably fixed to the target chamber  4 , for example, it is detachably fixed to the target chamber  4  by a screw  5 . The blocking unit  2  covers the middle of the opening  40 . 
     The width W 1  of the blocking unit  2  is equal to or greater than the width W 2  of the opening  40 , and the length L 1  of the blocking unit  2  accounts for 50%-75%, such as 55%, 60%, 65%, and 70% of the length L 2  of the opening  40 . 
     In an embodiment, four targets  1  are provided and arranged in-line, and the blocking unit  2  is arranged at the target  1  at the end in the arrangement direction. 
     In the embodiment of the present disclosure, the conditions before and after disposing the blocking unit  2  are respectively tested, and the specific results are as follows: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Test results before disposing the blocking unit 
               
            
           
           
               
               
               
            
               
                   
                 Measuring position 
                 Thickness of the window film before 
               
               
                   
                 (cm) 
                 improvement (nm) 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Upper 
                 7.5 
                 408.5 
               
               
                   
                   
                 15 
                 421.4 
               
               
                   
                 Middle 
                 29 
                 444.9 
               
               
                   
                   
                 43 
                 446.6 
               
               
                   
                   
                 57 
                 445.4 
               
               
                   
                   
                 71 
                 441.5 
               
               
                   
                 Lower 
                 85 
                 416 
               
               
                   
                   
                 92.5 
                 405.6 
               
            
           
           
               
               
               
            
               
                   
                 Uniformity 
                 90.44% 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Test results after disposing the blocking unit 
               
            
           
           
               
               
               
            
               
                   
                 Measuring 
                 Thickness of the window film after 
               
               
                   
                 position (cm) 
                 improvement (nm) 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Upper 
                 7.5 
                 419.9 
               
               
                   
                   
                 15 
                 424.9 
               
               
                   
                 Middle 
                 29 
                 429.7 
               
               
                   
                   
                 43 
                 433.1 
               
               
                   
                   
                 57 
                 432.9 
               
               
                   
                   
                 71 
                 428.3 
               
               
                   
                 Lower 
                 85 
                 422.4 
               
               
                   
                   
                 92.5 
                 417.5 
               
            
           
           
               
               
               
            
               
                   
                 Uniformity 
                 96.34% 
               
               
                   
                   
               
            
           
         
       
     
     Through research, it has been found that the present disclosure may significantly improve the uniformity of the film layer on the substrate  3 , and its uniformity increases from 90.44% to 96.34%, which may meet the actual needs of industrial production. 
     The structures, features, and effects of the present disclosure are described in detail based on the embodiments shown in the drawings. The above description is only the preferred embodiments of the present disclosure, but the present disclosure does not limit the scope of implementation as shown in the drawings. Any changes made according to the concept of the present disclosure, or equivalent embodiments that are modified to equivalent changes, should still fall within the protection scope of the present disclosure if they do not go beyond the spirit covered by the description and the drawings.