Abstract:
The invention provides a substrate structure for manufacturing a light-emitting diode and a method for manufacturing the light-emitting diode. The substrate structure comprises a substrate having a first surface and a second surface opposite to the first surface; and a plurality of grooving structure formed on the first surface of the substrate. In which, the light-emitting diode is formed on the first surface of the substrate.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to Taiwan Application Serial Number 102101655 filed Jan. 16, 2013, which is herein incorporated by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a substrate structure used for manufacturing a light-emitting diode and more particularly, to a lift-off substrate structure used for manufacturing a light-emitting diode. 
         [0004]    2. Description of Related Art 
         [0005]    In a conventional manufacturing process for a light-emitting diode, a first substrate is provided, and then a light-emitting diode structure is formed on the first substrate. Afterwards, a second substrate is jointed to the light-emitting diode structure, and the light-emitting diode structure is lifted off from the first substrate. In the conventional process, it further comprises forming a buffer layer or an oxide pattern sandwiched between the first substrate and the light-emitting diode structure. 
         [0006]    When the lift-off process is performed, an etching solution is used to remove the first substrate by way of a chemical etching process, so as to expose the surface of the light-emitting diode structure. In which, the etching solution is needed to permeate between the first substrate and the light-emitting diode structure, such that the lift-off process is accomplished. Nonetheless, in the conventional process, the interspace between the first substrate and the light-emitting diode structure is so narrow that the reactive area for etching is insufficient and the etching rate is slow. The slower etching rate makes the longer etching time, which may damage the light-emitting diode structure in the manufacturing process. 
         [0007]    Further, the light-emitting diode structure provided by the conventional etching process has a smooth surface, which needs performing a surface roughening step to satisfy an average light-emitting efficiency. As such, an additional manufacturing step is required, and thus the cost of production is increased. To solve the problems met in the art, there is a need for an improved substrate structure for manufacturing a light-emitting diode as well as a method for manufacturing the light-emitting diode. 
       SUMMARY 
       [0008]    The present disclosure provides a substrate structure for manufacturing a light-emitting diode and a method for manufacturing the light-emitting diode, so as to solve the problems of the prior art, and an improved manufacturing method is provided. 
         [0009]    One aspect of the present disclosure is to provide a substrate structure for manufacturing a light-emitting diode. The substrate structure comprises a substrate having a first surface and a second surface opposite to the first surface, and a plurality of notch structures forming in the first surface of the substrate. In which, the light-emitting diode is formed on the first surface of the substrate. 
         [0010]    Another aspect of the present disclosure is to provide a method for manufacturing the light-emitting diode. The method comprises the following steps. A first substrate is provided having a first surface and a second surface opposite to the first surface. A plurality of notch structures are formed in the first surface of the substrate. A light-emitting diode structure is formed on the first surface of the substrate. A second substrate parallel to the first substrate is formed on the surface of the light-emitting diode. Then, a lift-off process is performed to separate the first substrate and the light-emitting diode structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0012]      FIG. 1A to 1C  are side views of a substrate structure according to embodiments of the present disclosure; 
           [0013]      FIG. 1D  is a side view of a stacked structure according to one embodiment of the present disclosure; 
           [0014]      FIG. 1E  is a side view of a stacked structure according to one embodiment of the present disclosure; 
           [0015]      FIG. 1F  is a side view of a stacked structure according to one embodiment of the present disclosure; 
           [0016]      FIG. 1G  is a schematic view of a lift-off process according to one embodiment of the present disclosure; 
           [0017]      FIG. 1H  is a side view of a light-emitting diode according to one embodiment of the present disclosure; 
           [0018]      FIG. 2A to 2E  are cross-sectional views of a notch structure according to embodiments of the present disclosure; 
           [0019]      FIG. 3A  is a cross-sectional view of a stacked structure according to one embodiment of the present disclosure; and 
           [0020]      FIG. 3B  is a cross-sectional view of a stacked structure according to one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The a substrate structure used for manufacturing a light-emitting diode and a method for manufacturing the light-emitting diode of the embodiments are discussed in detail below, but not limited the scope of the present disclosure. The same symbols or numbers are used to the same or similar portion in the drawings or the description. And the applications of the present disclosure are not limited by the following embodiments and examples, which the person in the art can apply in the related field. 
         [0022]    The present disclosure provides a substrate structure used for manufacturing a light-emitting diode and a method for manufacturing the light-emitting diode. In which, the substrate structure comprises a plurality of notch structures, so as to increase the efficiency of a lift-off process. 
         [0023]      FIG. 1A to 1C  are side views of a substrate structure according to embodiments of the present disclosure. In  FIG. 1A , the first substrate  110  is provided, wherein the first substrate  110  has a first surface  112  and a second surface  114 . According to one embodiment of the present disclosure, the material of the first substrate is selected from a group comprising of sapphire, silicon, silicon carbide (SiC), lithium aluminate (LiAlO 2 ), lithium gallate (LiGaO 2 ), zinc oxide (ZnO), gallium arsenide (GaAs), gallium phosphide (GaP), and a combination thereof. 
         [0024]    In  FIG. 1B , a plurality of notch structures  116  are formed in the first surface  112  of the first substrate  110 . In which, the notch structures  116  are crisscrossed as a network. According to one embodiment of the present disclosure, the notch structures  116  are parallel as shown in  FIG. 1C . 
         [0025]    The notch structures  116  are a plurality of hollow recess structures formed by a dry etching method or a wet etching method, and are expended to the edges of the first substrate  110  to form a plurality of openings. 
         [0026]      FIG. 2A to 2E  are cross-sectional views of a notch structure according to embodiments of the present disclosure. In  FIG. 2A to 2E , the first substrate  210  has a plurality of notch structures  212 , and the cross section of the notch structures  212  is rectangle  212   a,  semicircle  212   b,  arc  212   c,  triangle  212   d,  trapezoid  212   e,  or a combination thereof. According to one example of the present disclosure, the depth of the notch structures  212  is in a range of 0.1 μm to 50 μm. 
         [0027]      FIG. 1D  is a side view of a stacked structure according to one embodiment of the present disclosure. Followed by  FIG. 1B , a light-emitting diode structure  120  is formed on the first surface  112  of the first substrate  110 . In which, the light-emitting diode structure  120  comprises an N-type semiconductor layer, a light-emitting layer, a P-type semiconductor layer and a conductive layer. The N-type semiconductor layer, the light-emitting layer the P-type semiconductor layer and the conductive layer is sequentially formed on the first surface  112  of the first substrate  110  to form a stacked structure  100   a.  According to one example of the present disclosure, the components of the light-emitting diode structure  120  comprise III-V semiconductor, such as gallium nitride (GaN) or indium phosphide (InP). According to one example of the present disclosure, the N-type semiconductor layer, the light-emitting semiconductor layer and the P-type semiconductor layer are formed by epitaxy methods. According to one example of the present disclosure, the conductive layer is formed by an electroplating or a deposition, and the method of the conductive layer is copper (Cu), nickel (Ni), molybdenum (Mo), aluminum (Al), or a combination thereof. 
         [0028]      FIG. 1E  is a side view of a stacked structure according to one embodiment of the present disclosure. In  FIG. 1E , the stacked structure  100   b  further comprises a buffer layer  130  formed between the first surface  112  of the first substrate  110  and the light-emitting diode structure  120 . In which, the buffer layer  130  is formed by an epitaxy method to provide the stacked structure  100   b.  Compared to the method of the N-type semiconductor layer in the light-emitting diode structure  120 , the material of the buffer layer  130  has better etching rate, and may improve the lift-off process of the first substrate  110 . However, according to one embodiment of the present disclosure, the lift-off process of the first substrate  110  is performed even the buffer layer  130  is lacked, and the light-emitting diode structure  120  may not be damaged. 
         [0029]    According to one example of the present disclosure, the depth of the buffer layer  130  is equal to or less than 100 nm. According to another example of the present disclosure, the material of the buffer layer  130  is silicon oxide (SiOx), silicon nitride (SiNx) or chromium nitride (CrN). 
         [0030]      FIG. 1F  is a side view of a stacked structure according to one embodiment of the present disclosure. In  FIG. 1F , a second substrate  140  followed by  FIG. 1D  is formed on the light-emitting diode structure  120  to form the stacked structure  100   c.  The second substrate  140  is parallel to the first substrate  110 . According to one embodiment of the present disclosure, the second substrate  140  is annealed with the light-emitting diode structure  120  by pressing on the second substrate  140 . According to one embodiment of the present disclosure, the second substrate  140  is a transparent substrate. According to another example of the present disclosure, the material of the second substrate  140  is selected from a group comprising of sapphire, silicon (Si), silicon carbide (SiC), lithium aluminate (LiAlO 2 ), lithium gallate (LiGaO 2 ), zinc oxide (ZnO), gallium arsenide (GaAs), gallium phosphide (GaP), and a combination thereof. 
         [0031]      FIG. 1G  is a schematic view of a lift-off process according to one embodiment of the present disclosure. In  FIG. 1G , the stacked structure  110   c  in  FIG. 100   c  is immersed in the etching solution  160  to isolate the first substrate  110  and the light-emitting diode structure  120 , so as to explode a surface of the light-emitting structure  120 . Since the etching solution  160  can flow into the first surface  112  of the first substrate  110 , the reactive rate of the etching solution  160  may be increased, so as to increase the etching rate. 
         [0032]      FIG. 1H  is a side view of a light-emitting diode according to one embodiment of the present disclosure. In  FIG. 1H , after the first substrate  110  in  FIG. 1G  is removed, the light-emitting diode structure  120  and the second structure  140  are reversed  180  degrees to provide the light-emitting diode  100   d,  wherein the light-emitting diode  120  is positioned on the second substrate  140 . According to one embodiment of the present disclosure, after the lift-off process, the exploded surface of the light-emitting diode  120  is rough, which may increase the light-emitting efficiency of the light-emitting diode  100   d.    
         [0033]      FIG. 3A  is a cross-sectional view of a stacked structure according to one embodiment of the present disclosure. In  FIG. 3A , the stacked structure  300   a  includes a first substrate  310 , a light-emitting diode structure  320   a  and a second substrate  330 . The first substrate  310  has a plurality of notch structures  312   a,  wherein the opening width (W 1 ) of the notch structure  312   a  is less than 10 μm. It is noteworthy that, when the opening width (W 1 ) of the notch structure  312   a  is less than 10 μm, the light-emitting diode structure  320   a  may be performed lateral epitaxy on the notch structure  312   a  to form a continuous light-emitting diode structure  320   a.  And the second substrate  330  is formed on the light-emitting diode structure  320   a  to provide the stacked light-emitting diode structure  300   a.    
         [0034]      FIG. 3B  is a cross-sectional view of a stacked structure according to one embodiment of the present disclosure. In  FIG. 3B , the stacked structure  300   b  includes a first substrate  310 , a light-emitting diode structure  320   b  and a second structure  330 . The first substrate  310  has a plurality of notch structures  312   b,  wherein the opening width (W 2 ) of the notch structure  312   b  is larger than 10 μm. It is noteworthy that, when the opening width (W 2 ) of the notch structure  312   a  is large than 10 μm, the light-emitting diode structure  320   a  cannot be performed lateral epitaxy on the notch structure  312   a,  and is formed a discontinuous light-emitting diode structure  320   b.  And the second substrate  330  is formed on the light-emitting diode structure  320   b  to provide the stacked light-emitting diode structure  300   b.    
         [0035]    In embodiments of the present disclosure, the etching solution flows into the notch structures formed on the first substrate, which may increase the reactive area for etching, and increase the etching rate to prevent the damage of the light-emitting diode structure. Therefore, the method for manufacturing the light-emitting diode provided by the present disclosure may solve the problems met in the art. 
         [0036]    On the other hand, after the lift-off process, the first substrate and the light-emitting diode structure are isolated, and the rough surface of the light-emitting diode is exploded. Therefore, there is no need an extra surface roughening step to improve the light-emitting efficiency of the light-emitting diode. Known as the above, the method for manufacturing the light-emitting diode provided by the present disclosure may simplify the process for manufacturing a light-emitting diode to decrease the producing cost. 
         [0037]    Although embodiments of the present disclosure and their advantages have been described in detail, they are not used to limit the present disclosure. It should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the present disclosure. Therefore, the protecting scope of the present disclosure should be defined as the following claims.