Patent Publication Number: US-2023143351-A1

Title: Display panel

Description:
TECHNICAL FIELD 
     The present disclosure relates to the display technology field, and in particular, to a display panel. 
     BACKGROUND 
     To reduce reflectivity of a display panel, a darkening layer can be added on a surface of a metal. In general, material of the darkening layer is metal oxynitride. In order to achieve patterning, a photoresist is coated on a surface of the darkening layer. Usually, the photoresist has a good adhesive force to a surface of a metal, especially copper, but a poor adhesive force to the surface of the darkening layer. During a photoetching process, the photoresist is used for two wet etching and two dry etching processes. The poor adhesive force will cause the photoresist to peel off during a second wet etching process, resulting in abnormal display. 
     SUMMARY 
     Embodiments of the present disclosure provide a display panel to solve a technical problem of the poor adhesive force between the photoresist and the darkening layer of the existing display panel during manufacture. 
     An embodiment of the present disclosure provides a display panel comprising a substrate, at least one metal layer disposed on the substrate, a darkening layer covering the at least one metal layer, and a functional layer covering the darkening layer, wherein an adhesive force of a photoresist to the functional layer is greater than an adhesive force of the photoresist to the darkening layer and an adhesive force of the functional layer to the darkening layer is greater than the adhesive force of the photoresist to the darkening layer, a material of the functional layer comprises a transparent conductive material, silicon nitride, or a metal with a thickness less than a skin depth, and the display panel further comprises a protecting layer covering the functional layer. 
     In a display panel according to an embodiment of the present disclosure, a thickness of the protecting layer ranges from 900 Å to 3000 Å. 
     In a display panel according to an embodiment of the present disclosure, a material of the darkening layer comprises one or any combination of metal oxide, metal nitride, metal oxynitride, molybdenum carbide alloy, and tungsten molybdenum alloy. 
     In a display panel according to an embodiment of the present disclosure, a thickness of the darkening layer ranges from 30 nm to 150 nm and a thickness of the functional layer ranges from 10 nm to 70 nm. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer comprises a copper layer, the darkening layer comprises molybdenum oxide, and the functional layer comprises indium tin oxide, wherein the thickness of the darkening layer ranges from 60 nm to 150 nm and the thickness of the functional layer ranges from 15 nm to 60 nm. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer comprises a copper layer, the darkening layer comprises molybdenum oxide, and the functional layer comprises silicon nitride, wherein the thickness of the darkening layer ranges from 30 nm to 70 nm and the thickness of the functional layer ranges from 10 nm to 50 nm. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer is a gate metal layer or a source drain metal layer. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer comprises two layers, one layer of the metal layer is a gate metal layer and the other layer of the metal layer is a source drain metal layer. 
     An embodiment of the present disclosure provides a display panel comprising a substrate, at least one metal layer disposed on the substrate, a darkening layer covering the at least one metal layer, and a functional layer covering the darkening layer, wherein an adhesive force of a photoresist to the functional layer is greater than an adhesive force of the photoresist to the darkening layer and an adhesive force of the functional layer to the darkening layer is greater than the adhesive force of the photoresist to the darkening layer. 
     In a display panel according to an embodiment of the present disclosure, a material of the functional layer comprises a transparent conductive material, silicon nitride, or a metal with a thickness less than a skin depth. 
     In a display panel according to an embodiment of the present disclosure, the display panel further comprises a protecting layer covering the functional layer. 
     In a display panel according to an embodiment of the present disclosure, a thickness of the protecting layer ranges from 900 Å to 3000 Å. 
     In a display panel according to an embodiment of the present disclosure, the transparent conductive material comprises one of indium tin oxide, indium zinc oxide, and indium gallium zinc oxide. 
     In a display panel according to an embodiment of the present disclosure, a material of the darkening layer comprises one or any combination of metal oxide, metal nitride, metal oxynitride, molybdenum carbide alloy, and tungsten molybdenum alloy. 
     In a display panel according to an embodiment of the present disclosure, a thickness of the darkening layer ranges from 30 nm to 150 nm and a thickness of the functional layer ranges from 10 nm to 70 nm. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer comprises a copper layer, the darkening layer comprises molybdenum oxide, and the functional layer comprises indium tin oxide, wherein the thickness of the darkening layer ranges from 60 nm to 150 nm and the thickness of the functional layer ranges from 15 nm to 60 nm. Alternatively, the thickness of the darkening layer is 70 nm and the thickness of the functional layer is 50 nm. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer comprises a copper layer, the darkening layer comprises molybdenum oxide, and the functional layer comprises silicon nitride, wherein the thickness of the darkening layer ranges from 30 nm to 70 nm and the thickness of the functional layer ranges from 10 nm to 50 nm. Alternatively, the thickness of the darkening layer is 50 nm and the thickness of the functional layer is 20 nm. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer is a gate metal layer or a source drain metal layer. 
     In a display panel according to an embodiment of the present disclosure, the at least one metal layer comprises two layers, one layer of the metal layer is a gate metal layer and the other layer of the metal layer is a source drain metal layer. 
     In the display panel provided in the embodiments of the present disclosure, the functional layer is provided on the darkening layer so that the adhesive force of the photoresist to the functional layer is greater than the adhesive force of the photoresist to the darkening layer in the prior art, and the adhesive force of the functional layer to the darkening layer is greater than the adhesive force of the photoresist to the darkening layer in the prior art, during the photoetching process of the metal layer, thereby improving the adhesive force of the photoresist and reducing a peeling risk of the photoresist. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To describe the technical solutions of the embodiments of the present disclosure more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments of the present disclosure. The accompanying drawings described below illustrate only some exemplary embodiments of the present disclosure, and persons skilled in the art may derive other drawings from the drawings without making creative efforts. 
         FIG.  1    is a schematic structural diagram illustrating a display panel according to a first embodiment of the present disclosure; 
         FIG.  2    is a relational diagram illustrating reflectivities of different layer structures at different wavelengths; 
         FIG.  3    is a relational diagram illustrating reflectivities of different layer structures at different wavelengths and wide viewing angels; and 
         FIG.  4    is a schematic structural diagram illustrating a display panel according to a second embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The technical solutions in the embodiments of the present disclosure will be described clearly and completely hereafter with reference to the accompanying drawings. Apparently, the described embodiments are only a part of but not all embodiments of the present disclosure. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure. 
     In description of the disclosure, it should be understood that orientational or positional relationships represented by directional terms mentioned in the present disclosure, such as central, longitudinal, lateral, length, width, thickness, up, down, front, rear, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, anticlockwise, etc., are orientational or positional relationships based on the drawings, and are merely for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element is intended to have a particular orientation, or is constructed and operated in a particular orientation, and therefore, should not be interpreted as a limitation of the application. In addition, terms such as “first” and “second” are used herein for purposes of description, and should not be interpreted as indication or implication of relative importance, or implied indication of a number of the technical features. Therefore, features limited by terms such as “first” and “second” can explicitly or impliedly include one or more than one of these features. In description of the disclosure, “a plurality of” means two or more than two, unless otherwise specified. 
     In the present disclosure, it is stated that, unless specified or limited otherwise, the terms “mounted,” “connected,” “coupled,” “fixed” and the like are interpreted broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections; may also be direct connections or indirect connections via intervening structures; may also be inner communications of two elements, which can be understood in the present disclosure by those skilled in the art according to specific situations. 
     In the present disclosure, unless specified or limited otherwise, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on,” “above,” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature; while a first feature “below,” “under,” or “on bottom of” a second feature may include an embodiment in which the first feature is right or obliquely “below,” “under,” or “on bottom of” the second feature, or just means that the first feature is at a height lower than that of the second feature. 
     Various embodiments and examples are provided in the following description to implement different structures of the present disclosure. In order to simplify the present disclosure, certain elements and settings will be described. However, these elements and settings are only by way of example and are not intended to limit the present disclosure. In addition, reference numerals may be repeated in different examples in the present disclosure. This repeating is for the purpose of simplification and clarity and does not refer to relations between different embodiments and/or settings. Furthermore, examples of different processes and materials are provided in the present disclosure. However, it would be appreciated by those skilled in the art that other processes and/or materials may be also applied. 
     Please refer to  FIG.  1    which is a schematic structural diagram illustrating a display panel according to a first embodiment of the present disclosure. 
     The embodiment of the present disclosure provides a display panel  100  comprising a substrate  11 , at least one metal layer  12 , a darkening layer  13 , a functional layer  14 , and a protecting layer  15 . 
     The at least one metal layer  12  is disposed on the substrate  11 , the darkening layer  13  covers the at least one metal layer  12 , the functional layer  14  covers the darkening layer  13 , and the protecting layer  15  covers the functional layer. 
     Specifically, in the display panel  100  according to the first embodiment, a number of the metal layer  12  is one and the metal layer  12  is a source drain metal layer  12 . Therefore, the display panel  100  also comprises a gate metal layer  16 , a first insulation layer  17 , an active layer  18 , and a second insulation layer  19  arranged on the substrate  11  in sequence. The source drain metal layer  12  (metal layer) is arranged on the second insulation layer  19 . The source drain metal layer  12  (metal layer) comprises data lines, sources, and drains. 
     Wherein an adhesive force of a photoresist to the functional layer  14  is greater than an adhesive force of the photoresist to the darkening layer  13  and an adhesive force of the functional layer  14  to the darkening layer  13  is greater than the adhesive force of the photoresist to the darkening layer  13 . 
     A patterning process of the source drain metal layer  12  (metal layer) according to the first embodiment comprises forming the darkening layer  13  on the source drain metal layer  12  firstly, wherein the darkening layer  13  can be formed by performing sputtering on a corresponding target material through physical vapor deposition or can also be formed by inputting oxygen, nitrogen or carbon dioxide when performing physical vapor deposition on a metal or metal alloy target material, then forming the functional layer  14  on the darkening layer  13 , forming the photoresist layer on the function layer  14  and exposing and developing the photoresist layer, and etching the source drain metal layer  12 , the darkening layer  13 , and the function layer  14  with the patterned photoresist layer as a shield to obtain the patterned source drain metal layer  12 . 
     A process of the source drain metal layer in the prior art comprises forming the darkening layer on the source drain metal layer, then forming the functional layer on the darkening layer, exposing and developing the photoresist layer, and etching the darkening layer and the source drain metal layer to obtain the patterned source drain metal layer. However, a poor adhesive force of the photoresist to the darkening layer will cause the photoresist to peel off during the etching process, thereby affecting a quality of the process. 
     Therefore, in the first embodiment, the functional layer  14  is added on the basis of prior art, and the adhesive force of the photoresist to the functional layer  14  is greater than the adhesive force of the photoresist to the darkening layer  13  and the adhesive force of the functional layer  14  to the darkening layer  13  is greater than the adhesive force of the photoresist to the darkening layer  13 . This configuration improves the adhesive force of the photoresist layer and reduces a peeling risk of the photoresist during the etching process. 
     Alternatively, a material of the functional layer  14  comprises a transparent conductive material, silicon nitride (SiN x ) or a metal with a thickness less than a skin depth, but not limited hereto, wherein the transparent conductive material comprises one or any combination of indium tin oxide (ITO), indium zinc oxide (IZO), and indium gallium zinc oxide (IGZO). When the material of the functional layer  14  comprises the metal, the thickness of the functional layer  14  should be less than the skin depth, so that the functional layer  14  has a property of light transmission, so as to reduce the reflectivity to external light. 
     In the first embodiment, a thickness of the protecting layer  15  ranges from 900 Å (comprising 900 Å) to 3000 Å (comprising 3000 Å), and the thickness of the protecting layer  15  in the first embodiment is not limited hereto. Alternatively, a material of the protecting layer  15  can comprise silicon nitride (SiN x ), silicon oxide (SiO x ), or silicon oxynitride (SiN x O y ), but not limited hereto. 
     In the first embodiment, a material of the darkening layer  13  comprises one or any combination of metal oxide, metal nitride, metal oxynitride, molybdenum carbide alloy, and tungsten molybdenum alloy. 
     Alternatively, the material of the darkening layer  13  comprises Mo a X b O c N d , Mo a X b W c , Mo a X b C c , or Al a O b N c , wherein a is a rational number greater than 0, b is a rational number greater than or equal to 0, c and d are rational numbers greater than or equal to 0, and X is at least one metal element of tantalum, vanadium, nickel, niobium, zirconium, tungsten, titanium, rhenium, and hafnium. In the first embodiment, the material of the darkening layer  13  is not limited hereto. 
     Alternatively, Mo a XbO c N d  comprises at least one of O and N and b is a rational number greater than 0, that is, Mo a XbO c N d  is molybdenum oxide alloy, molybdenum nitride alloy, or molybdenum oxynitride alloy. In Mo a X b W c , Mo a X b C c , and Al a O b N c , b and c are rational numbers greater than 0, that is, Mo a X b W c  is tungsten molybdenum alloy, Mo a X b C c  is molybdenum carbide alloy, and Al a O b N c  is aluminum oxynitride. 
     In the display panel  100  according to the first embodiment, a thickness of the darkening layer  13  ranges from 30 nm (comprising 30 nm) to 150 nm (comprising 150 nm) and the thickness of the functional layer  14  ranges from 10 nm (comprising 10 nm) to 70 nm (comprising 70 nm), wherein the above thicknesses of the darkening layer  13  and the functional layer  14  are restricted to reduce the reflectivity to external light. 
     Specifically, the metal layer  12  (the source drain metal layer) comprises a copper (Cu) layer, the darkening layer  13  comprises molybdenum oxide (MoO x ), and the functional layer  14  comprises indium tin oxide (ITO), that is, a structure in the first embodiment is Cu+MoO x +ITO+PV, wherein the PV is the protecting layer  15 . The thickness of the darkening layer  13  ranges from 60 nm (comprising 60 nm) to 150 nm (comprising 150 nm) and the thickness of the functional layer  14  ranges from 15 nm (comprising 15 nm) to 60 nm (comprising 60 nm). 
     Alternatively, the thickness of the darkening layer  13  is 70 nm and the thickness of the functional layer  14  is 50 nm. In this case, please refer to table 1, a reflectivity of a Cu+MoO x +ITO+PV structure is very close to that of a Cu+MoO x +PV structure and a reflectivity of a Cu+PV structure is 48.83%. Therefore, the reflectivity of the Cu+MoO x +ITO+PV structure in the first embodiment can be reduced from 48.83% to 7.35%. 
     
       
         
           
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Cu +  
                 Cu +  
                 Cu +  
                   
               
               
                   
                 Layer 
                 MoO x  +  
                 MoO x  +  
                 MoO x  + 
                 Cu +  
               
               
                   
                 structure 
                 PV 
                 ITO + PV 
                 SiN x  + PV 
                 PV 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Reflectivity/% 
                 7.3 
                 7.35 
                 7.33 
                 48.83 
               
               
                   
                   
               
            
           
         
       
     
     Specifically, please refer to  FIG.  2    which is a relational diagram illustrating reflectivities of different layer structures in table 1 at different wavelengths. According to  FIG.  2   , the reflectivities of the Cu+MoO x +ITO+PV structure in the first embodiment are close to that of the Cu+MoO x +PV structure at all wavelengths. 
     Refer to  FIG.  3    which is a relational diagram illustrating reflectivities of different layer structures in table 1 at different wavelengths and wide viewing angels. According to  FIG.  3   , the reflectivities of the Cu+MoO x +ITO+PV structure in the first embodiment are close to that of the Cu+MoO x +PV structure at all wavelengths and wide viewing angles. 
     Therefore, according to  FIG.  2    and  FIG.  3   , the Cu+MoO x +ITO+PV structure in the first embodiment is similar to the Cu+MoO x +PV structure in the prior art in terms of reflectivity. Therefore, the functional layer  14  added in the first embodiment not only improves the adhesive force of the photoresist, but also guarantees an effect of reducing reflectivity. 
     Alternatively, the metal layer  12  (the source drain metal layer) comprises a copper (Cu) layer, the darkening layer  13  comprises molybdenum oxide (MoO x ), and the functional layer  14  comprises silicon nitride (SiN x ), that is, a structure in the first embodiment is Cu+MoO x +SiN x +PV, wherein the PV is the protecting layer  15 . The thickness of the darkening layer  13  ranges from 30 nm (comprising 30 nm) to 70 nm (comprising 70 nm) and the thickness of the functional layer  14  ranges from 10 nm (comprising 10 nm) to 50 nm (comprising 50 nm). 
     Alternatively, the thickness of the darkening layer  13  is 50 nm and the thickness of the functional layer  14  is 20 nm. In this case, please refer to table 1, a reflectivity of a Cu+MoO x +SiN x +PV structure is very close to that of a Cu+MoO x +PV structure and a reflectivity of a Cu+PV structure is 48.83%. Therefore, the reflectivity of the Cu+MoO x +SiN x +PV structure in the first embodiment can be reduced from 48.83% to 7.33%. 
     Specifically, please refer to  FIG.  2    which is a relational diagram illustrating reflectivities of different layer structures in table 1 at different wavelengths. According to  FIG.  2   , the reflectivities of the Cu+MoO x +SiN x +PV structure in the first embodiment are close to that of the Cu+MoO x +PV structure at all wavelengths. 
     Please refer to  FIG.  3    which is a relational diagram illustrating reflectivities of different layer structures in table 1 at different wavelengths and wide viewing angels. According to  FIG.  3   , the reflectivities of the Cu+MoO x +SiN x +PV structure in the first embodiment are close to that of the Cu+MoO x +PV structure at all wavelengths and wide viewing angles. 
     Therefore, according to  FIG.  2    and  FIG.  3   , the Cu+MoO x +SiN x +PV structure in the first embodiment is similar to the Cu+MoO x +PV structure in the prior art in terms of reflectivity. Therefore, the functional layer  14  added in the first embodiment not only improves the adhesive force of the photoresist, but also guarantees an effect of reducing reflectivity. 
     While the first embodiment only recites the examples of above two structures, it is not limited hereto. 
     As shown in  FIG.  4   , a display panel  200  in a second embodiment differs from the display panel  100  in the first embodiment in that a number of the metal layer  22  is one and the metal layer  22  is the gate metal layer. 
     Therefore, the display panel  200  comprises the gate metal layer  22 , the darkening layer  23 , the functional layer  24 , and the protecting layer  25  arranged on the substrate  21  in sequence. The gate metal layer  22  (metal layer) comprises scan lines and gates. 
     In the display panel  200  in the second embodiment, structures and combination structures of the darkening layer  23 , the functional layer  24 , and the protecting layer  25  are similar to or same as that of the darkening layer  23 , the functional layer  24 , and the protecting layer  25  in the display panel  100  in the first embodiment. Reference may be made to the display panel  100  in the description in the first embodiment and details are not further described herein. 
     In some embodiments, the metal layer  22  comprises two layers, one layer of the metal layer is a gate metal layer and the other layer of the metal layer is a source drain metal layer, wherein the darkening layer, the functional layer, and the protecting layer are respectively arranged on the gate metal layer and the source drain metal layer. In the embodiment, the structure of the darkening layer, the functional layer, and the protecting layer arranged on the gate metal layer is similar to or same as that in the second embodiment, and please refer to the description of the second embodiment for details. In the embodiment, the structure of the darkening layer, the functional layer, and the protecting layer arranged on the source drain metal layer is similar to or same as that in the first embodiment, and please refer to the description of the first embodiment for details which are not further described herein. 
     In the display panel provided in the embodiments of the present disclosure, the functional layer is provided on the darkening layer so that the adhesive force of the photoresist to the functional layer is greater than the adhesive force of the photoresist to the darkening layer in the prior art, and the adhesive force of the functional layer to the darkening layer is greater than the adhesive force of the photoresist to the darkening layer in the prior art, during the photoetching process of the metal layer, thereby improving the adhesive force of the photoresist and reducing a peeling risk of the photoresist. 
     The display panel provided in the embodiments of the present disclosure is described in detail above. The principle and implementations of the present disclosure are described in this specification by using specific examples. The description about the foregoing embodiments is merely provided to help understand the method and core ideas of the present disclosure. Persons of ordinary skill in the art should understand that they may still make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements to some or all technical features thereof, without departing from the scope of the technical solutions of the embodiments of the present invention.