Patent Publication Number: US-2019198406-A1

Title: Substrate and package module including the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to package technology, and more particularly to a substrate and a package module including the substrate. 
     2. Description of the Related Art 
     The conventional package module is manufactured in a way that a metal ring is disposed on an upper surface of a substrate, a chip is then mounted on the upper surface of the substrate, and finally a solder paste is provided on the metal ring and a cap is attached to the metal ring through the solder paste. However, because the size of the package module is getting smaller, the flexibility of substrate layout will be limited by the metal ring. If the metal ring is too wide, there is insufficient space for better substrate layout, and if the metal ring is too narrow, the solder paste may be gathered in a certain area. As a result, the conventional package module still has drawbacks and therefore needs improvements. 
     SUMMARY OF THE INVENTION 
     It is a primary objective of the present invention to provide a substrate for a package module, which has the advantages of lowering costs, increasing available layout space, and reducing the size of the package module. 
     To attain the above objective, the present invention provides a substrate which includes a substrate body and an interconnection layer disposed on a bearing surface of the substrate body and having an annular portion and a plurality of first protrusions extending outward from an outer periphery of the annular portion. 
     Preferably, the interconnection layer has a plurality of second protrusions extending inward from an inner periphery of the annular portion. 
     Preferably, the annular portion and the first protrusions are formed integrally. 
     Preferably, the annular portion and the first protrusions are manufactured from metal. 
     It is a secondary objective of the present invention to provide a package module which includes the aforesaid substrate, a chip mounted on the bearing surface of the substrate body and surrounded by the annular portion of the interconnection layer, and a cap enclosing the chip and having a bottom thereof adhered to the interconnection layer of the substrate by an adhesive. 
     Preferably, the interconnection layer has a plurality of second protrusions extending inward from an inner periphery of the annular portion. 
     Preferably, the adhesive is solder paste. 
     Preferably, the annular portion and the first protrusions are formed integrally from metal. 
     It can be understood from the above illustration that when the bottom of the cap is attached to the interconnection layer of the substrate, the adhesive can be spread on the annular portion and the first protrusions of the interconnection layer to increase the bonding area of the adhesive, such that the bonding strength between the substrate and the cap can be enhanced, and the adhesive can be effectively gathered on the annular portion and the first protrusions. 
     As a result, by means of the first protrusions of the interconnection layer, the bonding area of the adhesive is enhanced, and the bonding strength between the substrate and the cap is increased. Further, the annular portion can be configured having a width smaller than the width of the conventional metal ring to increase available layout space of the substrate and reduce the size of the package module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a substrate according to a first preferred embodiment of the present invention. 
         FIG. 2  is a sectional view of a package module according to the first preferred embodiment of the present invention, showing the cap is attached to the interconnection layer through the adhesive. 
         FIG. 3  is an exploded perspective view of the package module according to the first preferred embodiment of the present invention. 
         FIG. 4  is a perspective view of the substrate according to a second preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a substrate  10  according to a first preferred embodiment of the present invention includes a substrate body  20  and an interconnection layer  30 . 
     The substrate body  20  in the present embodiment may, but unlimited to, be a printed circuit board (usually referred to as “PCB”), a bismaleimide-triazine (usually referred to as “BT”) substrate, a glass fiber substrate (usually referred to as “FR4”), a ceramic substrate, or a direct bonded copper (usually referred to as “DBC”) substrate. As such, the substrate body  20  has a relatively lower manufacturing cost. The substrate body  20  has a bearing surface  22 . 
     The interconnection layer  30  is disposed on the bearing surface  22  of the substrate body  20 . In the present embodiment, the interconnection layer  30  is a closed circuit; however, the interconnection layer  30  may have an opening according to actual needs. The interconnection layer  30  has an annular portion  38  and a plurality of first protrusions  32  extending outward from an outer periphery of the annular portion  38 . In the present embodiment, the annular portion  38  is a quadrilateral member with four lateral walls  34 . The first protrusions  32  each extend outward and horizontally from the outer periphery of one of the lateral walls  34 , and the first protrusions  32  each have a bottom side thereof fixedly mounted on the bearing surface  22  of the substrate body  20  and a top side thereof flush with the top sides of the lateral walls  34 . Further, each of the outer peripheries of the lateral walls  34  may be provided with one or more first protrusions  32 . Preferably, the outer peripheries of the two opposite lateral walls  34  have the same number of the first protrusions  32 . 
     In the present embodiment, the first protrusions  32  and the annular portion  38  are formed integrally, and more specifically, the first protrusions  32  and the lateral walls  34  are formed integrally to reduce production process and manufacturing costs. In other embodiment, the annular portion  38  can be first formed, and then the first protrusions  32  are formed on the outer peripheries of the lateral walls  34 . Besides, the annular portion  38  and the first protrusions  32  are manufactured from metal. In the present embodiment, since the annular portion  38  and the first protrusions  32  are formed integrally, they are made from the same material. In other embodiment, the annular portion  38  and the first protrusions  32  may be made from different metal according to actual needs. 
     Moreover, the shape of the annular portion  38  may be modified according to different requirements. For example, the annular portion  38  may be triangular, polygonal or irregular. 
     As shown in  FIG. 4 , in a second preferred embodiment, the interconnection layer  30  has a plurality of second protrusions  36 . The second protrusions  36  each extend inward and horizontally from an inner periphery of one of the lateral walls  34 , and the second protrusions  36  each have a bottom side thereof fixedly mounted on the bearing surface  22  of the substrate body  20  and a top side thereof flush with the top sides of the lateral walls  34 . The second protrusions  36  and the annular portion  38  are formed integrally from the same or different metal, and furthermore, each of the inner peripheries of the lateral walls  34  may be provided with one or more second protrusions  36 . Preferably, the inner peripheries of the two opposite lateral walls  34  have the same number of the second protrusions  36 . 
     As shown in  FIGS. 2-3 , a package module  40  of the present invention includes the aforesaid substrate  10 , a chip  50 , and a cap  60 . 
     The chip  50  is mounted on the bearing surface  22  of the substrate body  20  and surrounded by the annular portion  38  of the interconnection layer  30 . In the present embodiment, the chip  50  is an electric component or semiconductor component for receiving and processing electrical signals. Further, the chip  30  may be optionally and electrically connected to the interconnection layer  30  to prevent damage from static electricity. 
     The cap  60  is mounted on the bearing surface  22  of the substrate body  20  to define an accommodation chamber  70  with the substrate body  20  for enclosing the chip  50 . In the present embodiment, the cap  60  has a top plate  62 , an annular wall  64  extending downward from an outer periphery of the top plate  62 , and a bottom  66  formed at a bottom end of the annular wall  64 . The bottom  66  of the cap  60  is attached to the annular portion  38  and the first protrusions  32  of the interconnection layer  30  by an adhesive  80 . In the present embodiment, the adhesive  80  is solder paste. Further, since the two opposite lateral walls  34  have the same number of the first protrusions  32 , the adhesive  80  is spread evenly on the two opposites lateral walls  34 , such that the stresses generated between the cap  60  and the two opposite lateral walls  34  are equal to each other. 
     In the second preferred embodiment, in addition to the annular portion  38  and the first protrusions  32 , the bottom  66  of the cap  60  is attached to the second protrusions  36  of the interconnection layer  30  by the adhesive  80 . Further, since the two opposite lateral walls  34  have the same number of the second protrusions  36 , the adhesive  80  is spread evenly on the two opposites lateral walls  34 , such that the stresses generated between the cap  60  and the two opposite lateral walls  34  are equal to each other. 
     In summary, when the bottom  66  of the cap  60  is adhered to the interconnection layer  30  by the adhesive  80 , the adhesive  80  is spread on the top side of the annular portion  38 , the top sides of the first protrusions  32 , and the top sides of the second protrusions  36 , such that the bonding area of the adhesive  80  is enhanced, thereby increasing the bonding strength between the substrate  20  and the cap  60  and concentrating the adhesive  80  in the annular portion  38 , first protrusions  32 , and second protrusions  36 . Further, by means of the first and second protrusions  32 ,  36 , each of the lateral walls  34  can be designed having a width smaller than the width of the conventional metal ring to increase available layout space of the substrate  20  and reduce the size of the package module  40 , thereby enabling the package module  40  to achieve a lightweight design.