Abstract:
The present invention concerns a joining structure and a substrate-joining method using the same. The joining structure comprises a substrate, and comprises a plurality of joining patterns which are located on the said substrate and which are spaced apart from each other. The substrate-joining method using the joining structure can comprise: a stage involving the formation of a plurality of joining patterns which are spaced apart from each other on a first substrate; and a stage of joining a second substrate on the plurality of joining patterns. When the said joining structure is employed, it is possible to reduce or prevent damage due to spreading of the joining substance during joining of the two substrates.

Description:
FIELD OF THE INVENTION 
       [0001]    Embodiments of the present invention relate to a bonding structure and a substrate bonding method using the same. 
       BACKGROUND OF THE INVENTION 
       [0002]    In order to hermetically mount or vacuum mount a semiconductor device, two substrates need to be bonded. When bonding two substrates, a bonding material may be applied to either one or both of the two substrates. As a form of the bonding material changes during bonding, hermetic mounting or vacuum mounting of the two substrates is accomplished. 
         [0003]    A structure, such as a circuit, requiring protection may be located inside the bonding material on the substrates. Moreover, a pad or the like for electrical connection with an external device may be located outside the bonding material. During the bonding of the two substrates, if the bonding material spreads and comes in contact with the structure inside the bonding material or the pad outside the bonding material, this may deteriorate an operation of the structure or the pad. 
       SUMMARY OF THE INVENTION 
       [0004]    Therefore, the present invention provides a bonding structure capable of reducing or preventing damage caused by spreading of a bonding material during the bonding of two substrates, and a substrate bonding method using the same. 
         [0005]    In accordance with an aspect of the present invention, there is provided a bonding structure including: a substrate; and multiple bonding patterns provided on the substrate and spaced apart from each other. 
         [0006]    In accordance with another aspect of the present invention, there is provided a substrate bonding method including: forming multiple bonding patterns spaced apart from each other on a first substrate; and bonding a second substrate on the bonding patterns. 
         [0007]    Using the bonding structure in accordance with one embodiment of the present invention, when bonding a substrate to another substrate or the like, it is possible to reduce or prevent damage to a device on the substrate or to a pad for electrical connection between the substrate and an external device caused by spreading of a bonding material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a top plan view of a bonding structure in accordance with an embodiment of the present invention; 
           [0009]      FIG. 2  depicts a cross-sectional view taken along line A-A′ in  FIG. 1 ; 
           [0010]      FIG. 3  is a schematic view illustrating the separation distance between bonding patterns; 
           [0011]      FIG. 4  is a cross-sectional view showing another structure being bonded to the bonding structure in accordance with the embodiment of the present invention; and 
           [0012]      FIG. 5  is a top plan view showing a bonding structure in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0013]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. 
         [0014]      FIG. 1  is a top plan view of a bonding structure in accordance with an embodiment of the present invention, and  FIG. 2  is a cross-sectional view taken along line A-A′ in  FIG. 1 . 
         [0015]    Referring to  FIGS. 1 and 2 , the bonding structure includes a substrate  10  and multiple bonding patterns  20 . The substrate  10  may be formed of glass, silicon, or other appropriate material. Further, a circuit or device, a mechanical structure and the like may be formed on the substrate  10 . 
         [0016]    The multiple bonding patterns  20  are provided on the substrate  10 . The bonding patterns  20  are provided for bonding the substrate  10  to another structure, and may be formed of a material which is capable of bonding. The bonding patterns  20  may include one or several layers. In an embodiment of the present invention, the bonding patterns  20  are formed in one layer, and the material for the bonding patterns  20  may be a eutectic solder, a high-melting-point solder, a lead-free solder, gold, or a gold alloy. 
         [0017]    In another embodiment of the present invention, the bonding patterns  20  are formed in multiple layers, and the bonding patterns  20  may be formed of two or more combinations of various metals, including the aforementioned materials, copper or a copper alloy, titanium or a titanium alloy, chrome or a chrome alloy, nickel or a nickel alloy, aluminum or an aluminum alloy, vanadium or a vanadium alloy and the like. 
         [0018]    The bonding patterns  20  are formed by patterning a layer of a bonding material formed on the substrate  10 . Meanwhile, the number of bonding patterns  20  shown in  FIGS. 1 and 2  are for illustrative purposes, and the number of bonding patterns  20  may vary depending upon a size of a substrate to be bonded, constituent materials or the like. Each of the bonding patterns  20  may be formed in a shape suitable to bond the substrate  10  and another structure. For instance, the bonding pattern  20  may have a shape, such as a straight line, a bent line, or a curve. Further, the bonding pattern  20  may have a shape of a closed curve. For example, the bonding pattern  20  may be formed in a closed curve along the outline of the substrate  10 . 
         [0019]    The bonding pattern  20  having a line shape may be formed with a predetermined height h on the substrate  10 . In addition, the line-shaped bonding pattern  20  may have a predetermined thickness t. The thickness t and height h of the bonding pattern  20  may be determined depending on the process of forming a bonding material. The thicknesses t of the bonding patterns  20  may be identical or different with one another. Likewise, the heights h of the bonding patterns  20  may be identical or different. 
         [0020]    For instance, in an application where the separation height between the two substrates to be bonded is intended to be small, the height h of the bonding pattern  20  may be identical to or smaller than the thickness t. Even when a high aspect ratio of bonding pattern  20  is required, the height h may be less than 10 times the thickness t. In one embodiment, in a case of using multiple bonding patterns  20 , the thickness t of each of the bonding patterns  20  may be about 40 μm, and the height h thereof may be about 30 μm. Meanwhile, each of the bonding patterns  20  may be spaced apart from one another by a predetermined distance d on the substrate  10 . The separation distance d between the bonding patterns  20  may be determined based on the height h and thickness t of the bonding patterns  20  and a process of forming the bonding patterns  20 . 
         [0021]    In one embodiment, the separation distance d between the bonding patterns  20  may be ½ of the sum of the thicknesses t of adjacent bonding patterns  20 . However, in consideration of a process margin, the separation distance d may be less than the sum of the thicknesses t of the adjacent bonding patterns  20 . That is, when the thicknesses t of the adjacent bonding patterns  20  are identical with one another, the separation distance d may be less than two times (2t) the thickness t. 
         [0022]    Additionally, in another embodiment, in case where some of the materials of the bonding patterns  20  are used for bonding, the separation distance d between the bonding patterns  20  may be less than ½ of the sum of the thicknesses t of adjacent bonding patterns  20 . 
         [0023]      FIG. 3  shows a schematic view for explaining the separation distance between bonding patterns in a bonding structure. 
         [0024]    The schematic view of  FIG. 3  is an exemplary one in which an n-number of bonding patterns  20   1  to  20   n  are formed on a substrate. Here, n is an arbitrary natural number, and  FIG. 3  shows only some of the n-number of bonding patterns  20   1  to  20   n  and the number of bonding patterns  20   1  to  20   n  is not limited to a specific number. 
         [0025]    Referring to  FIG. 3 , for instance, the separation distance between an i-th bonding pattern  20   i  and an (i+1)-th bonding pattern  20   i+1  adjacent to each other is denoted by d i , and the thicknesses of the i-th bonding pattern  20   i  and the (i+1)-th bonding pattern  20   i+1  are denoted by t i  and t i+l , respectively. In this case, the i-th bonding pattern  20   i  and the (i+1)-th bonding pattern  20   i+1  may have the same thickness (i.e., t i =t i+1 ), or have a different thickness (i.e., t i ≠t i+1 ). 
         [0026]    Assuming that all the materials of the bonding pattern  20  are used for bonding and spread evenly, the separation distance d i  between the i-th bonding pattern  20   i  and the (i+1)-th bonding pattern  20   i+1  may be equal to ½ of the sum of the thicknesses t i  and t i+1  of the adjacent bonding patterns  20   i  and  20   i+1 . However, in consideration of a process variation in the thicknesses t of the bonding patterns  20   i  and  20   i+1 , the separation distance d i  may be less than the sum of the thicknesses t i  and t i+1  of the bonding patterns  20   i  and  20   i+1 . 
         [0027]    For instance, in one embodiment, in case where the heights of the i-th bonding pattern  20   i  and the (i+1)-th bonding pattern  20   i+1  are commonly about 30 μm, and the thicknesses t i  and t i+1  thereof are about 40 μm and about 30 μm, respectively, if all the materials of both of the bonding patterns  20   i  and  20   i+1  spread to the space between the bonding patterns  20   1  and  20   i+1 , the separation distance d i  between the bonding patterns  20   i  and  20   i+1  may be less than about 70 μm. 
         [0028]    In another embodiment, in case where some of the materials of the bonding patterns  20   i  and  20   i+1  are used for bonding and remainders thereof keep the separation distance between the bonding substrates, the separation distance d 1  between the two bonding patterns  20   i  and  20   i+1  may be less than ½ of the sum of the thicknesses t 1  and t i+1  of the two bonding patterns  20   i  and  20   i+1 . For example, if it is assumed that only half parts of the i-th bonding pattern  20   i  and the (i+1)-th bonding pattern  20   i+1 +, whose thicknesses t i  and t i+1  are about 40 μm and about 30 μm, respectively, are used for bonding, the separation distance d i  between the two bonding patterns  20   i  and  20   i+1  may be less than about 35 μm. 
         [0029]      FIG. 4  is a cross-sectional view showing the bonding structure bonded to an external substrate in accordance with the embodiment. 
         [0030]    Referring to  FIG. 4 , a substrate  30  is bonded on top of multiple bonding patterns  20 . For example, the substrate  30  is provided on the bonding patterns  20  and heat and/or pressure is applied between the two substrates  10  and  30  to partially melt the bonding patterns  20 . The metal patterns  20  and the substrate  30  may be bonded together by the molten materials of the bonding patterns  20 . The substrate  30  may include glass, silicon, or other suitable materials. 
         [0031]    Meanwhile, each of the bonding patterns  20  spreads in a horizontal direction on the substrate  10  as it melts. The bonding patterns  20  spread to regions B between the bonding patterns  20  because the bonding patterns  20  are spaced apart from one another. As each of the bonding patterns  20  spreads in the horizontal direction, the bonding patterns  20  can be connected to each other. Since the bonding patterns  20  spread to the regions B between the bonding patterns  20 , the bonding force between the bonding patterns  20  and the substrate  30  may be relatively improved without increasing regions of the bonding patterns  20 . 
         [0032]    Moreover, since the bonding patterns  20  spread to the regions B between the bonding patterns  20 , the amount of the materials of the bonding patterns  20  spreading to regions A outside the regions of the bonding patterns  20  may be relatively reduced. Therefore, it is possible to reduce or prevent deterioration of the operation of a device or pad on the substrate  10  which can be caused by externally spreading of the materials of the bonding patterns  20 . 
         [0033]      FIG. 5  is a top plan view showing a bonding structure in accordance with another embodiment of the present invention. 
         [0034]    Referring to  FIG. 5 , the bonding structure includes a substrate  10  and multiple bonding patterns  41 ,  42 , and  43 . The configuration of the substrate  10  is substantially identical to the previous embodiment described with reference to  FIGS. 1 to 4 . Therefore, a detailed description thereof will be omitted. 
         [0035]    The bonding patterns  41 ,  42 , and  43  are provided on the substrate  10  and are spaced apart from one another. The bonding patterns  41 ,  42 , and  43  may be divided into one first bonding pattern  41  and one or more second bonding patterns  42  and  43  depending on shapes. 
         [0036]    The number of second bonding patterns  42  and  43  shown in  FIG. 5  are for illustrative purposes, and the number of second bonding patterns  42  and  43  may vary depending on a size of a substrate to be bonded, constituent materials and the like. 
         [0037]    The first bonding pattern  41  is provided innermost among the bonding patterns  41 ,  42 , and  43 . Further, the first bonding pattern  41  has a closed curve shape. One or more second bonding patterns  42  and  43  are provided to sequentially enclose the first bonding pattern  41 . Further, the one or more second bonding patterns  42  and  43  may be provided with openings  200  and  300 , respectively. 
         [0038]    Since the bonding pattern  42  is provided with the opening  200 , a gas between the bonding pattern  41  and the bonding pattern  42  can be released from the substrate  10  through the opening  200  even if another structure is bonded onto the bonding patterns  41 ,  42 , and  43 . Likewise, a gas between the bonding pattern  42  and the bonding pattern  43  can be released from the substrate  10  through the opening  300  provided in the bonding pattern  43 . As a result, gases are prevented from being confined in the space between the bonding patterns  41 ,  42 , and  43 , so that a reduction in bonding yield can be avoided. 
         [0039]    While the invention has been shown and described with respect to the particular embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the of the invention as defined in the following claims. 
         [0040]    Embodiments of the present invention may be applied to a bonding structure and a substrate bonding method using the same.