Patent Publication Number: US-10314178-B2

Title: Package module

Description:
RELATED APPLICATIONS 
     This is a continuation application of the U.S. application Ser. No. 15/067,146, filed Mar. 10, 2016, which claims priority to China Application Serial Number 201510333366.5, filed Jun. 16, 2015, which is herein incorporated by reference. 
    
    
     BACKGROUND 
     Field of Invention 
     The present disclosure is related to a package module, and more particularly, to a package module in which the amount of encapsulant can be saved. 
     Description of Related Art 
     High efficiency, high density, and high reliability have been the tendencies toward which the power electronic devices are developed, in order to achieve the objects of energy-saving, cost reduction, and a good lifetime. For example, the integrated power module (IPM), in which multiple semiconductor devices are integrated into a device package, provides the possibility of further improving the space utilization in a package. 
     In a packaging process, it is often necessary to fill protective encapsulant into the housing to electrically isolate inner electronic components and to protect wires or terminals on the electronic components. Because height differences often exist among the electronic components, the protective encapsulant on electronic components with a low height may have an excess thickness, which corresponds to an unnecessary cost. 
     SUMMARY 
     The present disclosure provides a package module, in which a frame is disposed next to at least one side of an electronic component to locally heighten an encapsulant. 
     One embodiment of the present disclosure provides a package module including a circuit board, an electronic component disposed on the circuit board, a frame disposed next to at least one side of the electronic component, and an encapsulant. A gap is formed between the frame and the electronic component, wherein the encapsulant includes a first portion covering at least a part of the circuit board and a second portion filling into at least a part of the gap. The first portion is connected to the second portion. The first portion has a first height relative to the circuit board, and the second portion has a second height relative to the circuit board, wherein the second height is greater than the first height. 
     Another embodiment of the present disclosure is a packaging method for the above-mentioned package module, including disposing the electronic component on the circuit board; disposing the frame next to the at least one side of the electronic component so as to form the gap between the frame and the electronic component; and filling the encapsulant, wherein a portion of the encapsulant covers on at least a part of the circuit board so as to be the first portion, and another portion of the encapsulant fills into at least a part of the gap so as to be the second portion. 
     In this package module which is packaged in a housing, the frame is disposed next to the at least one side of the electronic component, and the encapsulant is filled into the gap between the frame and the electronic component. As a result, the height of the encapsulant covering the electronic component may be higher than that of other portion of the encapsulant (e.g. the encapsulant covering the circuit board), and therefore the amount of the encapsulant is reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
         FIG. 1  to  FIG. 5  are respectively cross-sectional views of different embodiments of a package module of the present disclosure. 
         FIG. 6A  and  FIG. 6B  are respectively a front view and a side view of an embodiment of a package module of the present disclosure, in which a frame is fixed to the circuit board. 
         FIG. 7  is a cross-sectional view of another embodiment of a package module of the present disclosure. 
         FIG. 8A  and  FIG. 8B  are respectively a partial side view and a partial top view of another embodiment of a package module of the present disclosure. 
         FIG. 9A  and  FIG. 9B  are respectively a partial side view and a partial top view of another embodiment of a package module of the present disclosure. 
         FIG. 10A  and  FIG. 10B  are respectively a partial side view and a partial top view of another embodiment of a package module of the present disclosure. 
         FIG. 11  is a partial cross-sectional view of another embodiment of a package module of the present disclosure. 
         FIG. 12  is a partial enlarged view of another embodiment of a package module of the present disclosure. 
         FIG. 13  to  FIG. 17  are respectively schematic views of frames in different embodiments of a package module of the present disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following, the spirit of the present disclosure will be described in detail via the illustration of the figures and the detailed description. Persons having ordinary skills in the art after understanding the preferred embodiments of the present disclosure would be able to modify and change the teaching of the present disclosure, and these modifications and changes do not depart from the spirit and scope of the present disclosure. 
     Reference is made to  FIG. 1 , which is a cross-sectional view of an embodiment of a package module of the present disclosure. The package module  100  includes a circuit board  110 , an electronic component  120  disposed on the circuit board  110 , a frame  130  disposed next to at least one side of the electronic component  120 , and an encapsulant  140 . A gap g is formed between the frame  130  and the electronic component  120 . The encapsulant  140  includes a first portion  142  covering at least a part of the circuit board  110  and a second portion  144  filling into at least a part of the gap g, wherein the first portion  142  has a first height h 1  relative to the circuit board  110 , and the second portion  144  has a second height h 2  relative to the circuit board  110 . The second height h 2  is greater than the first height h 1 . Obviously, the first portion  142  and the second portion  144  of the encapsulant  140  are connected. 
     More specifically, the thickness (height) of a certain portion of the encapsulant  140 , such as the thickness of the second portion  144 , is greater than the thickness of another portion of the encapsulant  140 , such as the thickness of the first portion  142 . This means that the encapsulant  140  is locally thickened by the frame  130  at the proximity of the electronic component  120 , thus saving the amount of the encapsulant  140 . By the capillary action, it would be more easily to achieve the local thickening of the encapsulant  140  at the proximity of the electronic component  120 . 
     The package module  100  is a package module packaged in a housing, that is, the package module  100  includes a housing  150  assembled on the circuit board  110 , while the electronic component  120  and the frame  130  are in the housing  150 . The encapsulant  140  may be poured into the housing  150  to cover the circuit board  110  and to fill the gap g. 
     The electronic component  120  and a pin  160  can be fixed to the circuit board  110  by welding with solder. The encapsulant  140  covering on the circuit board  110  can protect the connections of the pin  160  and the electronic component  120  to the circuit board  110 . 
     The electronic component  120  can include a plurality of bonding regions  122 . The bonding regions  122  are regions for electrical connection and are to be sealed by the encapsulant  140 , but the present disclosure is not limited thereto. The electronic component  120  can be connected to the circuit board  110  via the bonding regions  122  and by welding with solder, and then the bonding regions  122  are encapsulated by the encapsulant  140 . The electronic component  120  can be a capacitor, a resistor, an inductor, a chip, a transformer, a switch, a binding wire or similar devices, but the present disclosure is not limited thereto. The bonding regions  122  of the electronic component  120  can be located at the bottom surface of the electronic component  120 , the side surface of the electronic component  120 , the top surface of the electronic component  120 , or a combination of these, but the present disclosure is not limited thereto. Number of the bonding region  122  for each electronic component  120  can be one or more. In the present embodiment, number of the bonding region  122  in each electronic component  120  can be two, while two bonding regions  122  can be generally located at two opposite sides of the electronic component  120 , and the bonding regions  122  can extend from the side surfaces of the electronic component to the bottom surface and the top surface of the electronic component. 
     In some embodiments, the encapsulant  140  covers the bonding regions  122  on the electronic component  120 . The encapsulant  140  provides, in addition to the function of electrical isolation, insulation against moisture, preventing moisture from affecting the bonding regions  122  of the electronic component  120  and thus protecting the electronic component  120 , but the present disclosure is not limited thereto. 
     The housing  150  can include a through hole  152 , wherein an end of the pin  160  can be fixed to the circuit board  110  and the other end of the pin  160  can pass through the through hole  152  to be exposed from the housing  150  so as to connect to an exterior circuit, but the present disclosure is not limited thereto. 
     The housing  150  can include an encapsulant injection port  154 , wherein the encapsulant  140  is filled into the housing  150  via the encapsulant injection port  154 . The encapsulant  140  can be a gel such as organic silica gel or epoxy resin, etc. 
     In the present embodiment, the position of the encapsulant injection port  154  is not overlapped with that of the electronic component  120 , that is, the vertical projection of the encapsulant injection port  154  onto the circuit board is not overlapped with the electronic component, but the present disclosure is not limited thereto. For example, in another embodiment, the position of the encapsulant injection port  154  can be overlapped with that of the electronic component  120 . The encapsulant  140  may have at least two portions. The encapsulant  140  can cover on at least a part of the circuit board  110  to form the first portion  142 . The first height h 1  of the first portion  142  may be greater than the distance between the bottom end of the frame  130  and the circuit board  110 , so that the encapsulant  140  can climb up, by the capillary action, from the bottom of the gap g to fill into the gap g and thus form the second portion  144 , but the present disclosure is not limited thereto. As a result, the encapsulant  140  can cover the bonding regions  122  of the electronic component  120  and form the second portion  144  of the encapsulant  140 . The second portion  144  has a larger height (e.g. the second height h 2 ) while the first portion  142  has a smaller height (e.g. the first height h 1 ). 
     Reference is made to  FIG. 2 , which is a cross-sectional view of another embodiment of a package module of the present disclosure. In the present embodiment, the position of the encapsulant injection port  154  of the housing  150  is overlapped with that of the electronic component  120 , that is, the vertical projection of the encapsulant injection port  154  onto the circuit board  110  is overlapped with the electronic component  120 . In this situation, after filled into the housing  150  from the encapsulant injection ports  154 , the encapsulant  140  would flow from top ends of the electronic component  120  and the frame  130  downward to cover the circuit board  110 . The frame  130  has an opening  132  over the electronic component  120 , wherein the encapsulant  140  can flow via the opening  132  into the gap g between the frame  130  and the electronic component  120 . The excess portion of the encapsulant  140  outside of the frame  130  would flow downward by the action of the gravity, while the portion of the encapsulant  140  inside of the frame  130  (i.e. the second portion  144  of the encapsulant  140  in the gap g) would be retained in the gap g by the action of surface tension. 
     As a result, the bottom end of the frame  130  can be higher than the first portion  142  of the encapsulant  140 , as shown in  FIG. 2 . Alternatively, the bottom end of the frame  130  can be embedded in the first portion  142  of the encapsulant  140 , as shown in  FIG. 1 . 
     The distance of the gap g (i.e. the distance between the frame  130  and the electronic component  120 ) can be obtained by specific design. In an embodiment, the minimum distance of the gap g is preferably less than or equal to 2 mm; for example, it can be 0.5 mm, 1 mm, 1.5 mm, etc., but the present disclosure is not limited thereto. 
     Reference is made to  FIG. 3 , which is a cross-sectional view of another embodiment of a package module of the present disclosure. In the present embodiment, the frame  130  and the housing  150  are connected. Material for the frame  130  and that for the housing  150  can be both plastics, but the present disclosure is not limited thereto. The frame  130  and the housing  150  can be integrally formed by, for example, injection molding, and the position and the dimensions of the frame  130  can be determined by the distribution and the size of the electronic components  120  on the package module  100 , but the present disclosure is not limited thereto. 
     In other embodiments, the frame  130  can also be assembled to the housing  150  by any other appropriate method. As shown in  FIG. 4 , the frame  130  and the housing  150  can be combined by hooking, clipping, screwing, etc. Specifically, a recess  158  can be formed on the inner wall at the top of the housing  150 , and the frame  130  includes a flange  134  corresponding to the recess  158 . By inserting the flange  134  into the recess  158 , the frame  130  can be combined with the housing  150 . 
     Alternatively, as shown in  FIG. 5 , the frame  130  and the housing  150  can also be combined by glue  170 . In this situation, the housing  150  preferably has a position mark so that the frame  130  can be combined to the housing  150  at the correct position. 
     In other embodiments, the frame  130  can also be fixed to, for example, the circuit board  110 , as shown in  FIG. 6A  and  FIG. 6B , wherein  FIG. 6A  is a front view of the frame  130  fixed to the circuit board  110 , and  FIG. 6B  is a side view of the frame  130  fixed to the circuit board  110 . The frame  130  may be fixed to the circuit board  110  by the glue  170 , but the present disclosure is not limited thereto. The frame  130  may have an opening  132  at the top of the electronic component  120  (see  FIG. 1 ), and the encapsulant may be filled via the opening  132  into the gap between the frame  130  and the electronic component (not shown in the figures). Alternatively, via holes  137  can be formed on the sidewall of the frame  130 , so that the encapsulant can flow via the via holes  137  into the gap between the frame  130  and the electronic component. 
     Accordingly, the frame  130  can be combined to the housing  150 , to the circuit board  110 , or to both of the housing  150  and the circuit board  110  by several methods such as by integrally formed with the housing  150  and/or the circuit board  110 , by connected with glue, by clamping, or by locking with screw, etc. The frame  130  can have a different shape as long as the function described herein can be realized. In other embodiments, the frame  130  is not limited to be connected with the housing  150  or the circuit board  110 , as long as the frame  130  can be fixed. 
     Reference is made to  FIG. 7 , which is a cross-sectional view of another embodiment of a package module of the present disclosure. In some embodiments, there may be a situation where two electronic components  120  disposed on the circuit board  110  are closely adjacent. In such a situation where the space is limited, the two electronic components  120  can share a frame. For example, a T shape frame  130 ′ is disposed between the two electronic components  120 . If the distance between the electronic components  120  is further reduced, it is also possible to directly use the gap formed between the electronic components  120 . In other words, in an embodiment, frames such as L shape frames  130  can be disposed at only one side (the outer side) of two adjacent electronic components  120 , while at the other side (the inner side of two adjacent electronic components  120 ), a T shape frame  130 ′ is disposed or no frame is disposed. 
     Reference is made to  FIG. 8A  and  FIG. 8B , which are respectively a partial side view and a partial top view of another embodiment of a package module of the present disclosure. In some embodiments, the bonding region  122  of one or more electronic components  120  can be disposed at the top surface (i.e. the surface opposite and parallel to the circuit board) of the electronic component  120 . A gap g may be formed between the frame  130  and the top surface of the electronic component  120 , and the encapsulant  140  fills the gap g. To cover the bonding region  122  by the encapsulant  140 , the outer edge of the frame  130  preferably extends beyond the outer edge of the electronic component  120  by a distance d 1 . The distance d 1  for example can be greater than 0.2 mm, but the present disclosure is not limited thereto. 
     In other embodiments, the frame  130  can have a distributed structure. For example, the frame  130  may include a plurality of sheets  136 , as shown in  FIG. 9A  and  FIG. 9B . A bonding region  122  is disposed on the top surface of the electronic component  120 , and the sheets  136  can be paralleled arranged in array on the top surface of the electronic component  120  and can be fixed over the electronic component  120  by, for example, connecting to the housing, but the present disclosure is not limited thereto. The sheets  136  can also be disposed at other surfaces of the electronic component  120 . A gap g is also formed between the sheets  136  and the electronic component  120 , and the encapsulant  140  is filled in the gap g. The distance d 2  between the adjacent sheets  136  may be less than 1.5 mm, to ensure the encapsulant  140  still covers the bonding region  122  at the center point of the two adjacent sheets  136  and thus provides effects of electrical isolation and protection, but the present disclosure is not limited thereto. Similarly, the outer edge of the frame  130  preferably extends beyond the outer edge of the electronic component  120  by a predetermined distance d 1 , but the present disclosure is not limited thereto. 
     In other embodiments, the frame  130  is not limited to blocks or sheets. As shown in  FIG. 10A  and  FIG. 10B , the frame  130  can includes a plurality of columns  138 . To cover the bonding region  122  by the encapsulant  140 , the distance d 2  between the adjacent columns  138  can be preferably less than or equal to than 1.5 mm, but the present disclosure is not limited thereto. The cross-section of each column  138  can be square, circular or in other shapes. The outer edge of the frame  130  can extend beyond the outer edge of the electronic component  120  by a predetermined distance d 1 , but the present disclosure is not limited thereto. 
     Reference is made to  FIG. 11 , which is a partial cross-sectional view of another embodiment of a package module of the present disclosure. The bonding regions  122  of the electronic component  120  are disposed at two sides of the electronic component  120 , and parts of the bonding regions  122  are disposed at the top surface and the bottom surface of the electronic component  120 . An outer edge of the frame  130  can extend beyond an edge of the bonding region  122  at the top surface of the electronic component  120  by a distance d 3 . The distance d 3  is, for example, at least 0.2 mm, so that the encapsulant  140  filled into the gap g between the frame  130  and the electronic component  120  covers the bonding region  122  at the top surface of the electronic component  120 , but the present disclosure is not limited thereto. 
     The bottom end of the frame  130  can be embedded into the encapsulant  140  or not. If the bottom end of the frame  130  is not embedded into the encapsulant  140 , the distance d 4  between the bottom end of the frame  130  and the encapsulant  140  may less than or equal to 1 mm, so that the encapsulant  140  can flow into the gap g by the adhesion force between the encapsulant  140  and the sidewall of the electronic component  120 , but the present disclosure is not limited thereto. 
     Reference is made to  FIG. 12 , which is a partial enlarged view of another embodiment of a package module of the present disclosure. The shape of the frame  130  may be in accordance to the surface of the electronic component  120 , so as to form a gap g between the frame  130  and the electronic component  120 . For example, if the surface of the electronic component  120  is in irregular shape as shown in  FIG. 12 , the corresponding frame  130  can be in a corresponding irregular shape, to ensure the gap g stable between the frame  130  and the electronic component  120 . 
     Reference to  FIG. 13 , the frame  130  can be in a reversed L shape and can be disposed at a side of the electronic component  120 . The frame  130  can include a vertical portion  131  and a horizontal portion  133  connected together, wherein an angle between the vertical portion  131  and the horizontal portion  133  is approximately (but not limited to) 90 degree. A part of the gap g may be formed between the vertical portion  131  and electronic component  120 , and another part of the gap g may be formed between the horizontal portion  133  and the electronic component  120 . The vertical portion  131  and the horizontal portion  133  can be integrally formed and can include an insulation material, but the present disclosure is not limited thereto. For example, the vertical portion  131  and the horizontal portion  133  may also be comprised by the distributed structures, such as that shown in  FIG. 9A  to  FIG. 10B . 
     Both the vertical portion  131  and the horizontal portion  133  can be flat plates. As shown in  FIG. 13 , the facing sides to the electronic component  120  of the vertical portion  131  and the horizontal portion  133  are both flat. 
     Alternatively, in other embodiments, as shown in  FIG. 14 , the frame  130  further includes a protrusion  135  connected to the inner surface of the vertical portion  131 . The protrusion  135  can be integrally formed with the vertical portion  131 , and at least a part of the gap g is also formed between the protrusion  135  and the electronic component  120 . The protrusion  135  can be a rib, a column, a bump, a projection, or in other shapes. In this situation, the minimum distance of the gap g may be achieved between the protrusion  135  and the electronic component  120 . The minimum distance is less than or equal to 1 mm, but the present disclosure is not limited thereto. In other embodiments, the protrusion  135  can also be disposed on the horizontal portion  133  of the frame  130 , as shown in  FIG. 15 . 
     Alternatively, via holes  137  can be disposed at the vertical portion  131  of the frame  130 , as shown in  FIG. 16 , to save the material of the frame  130  and facilitate the encapsulation of the bonding region  122 . Size of via holes  137  and the ratio of via holes  137  to the vertical portion  131  can be controlled in certain range to ensure that the bonding region  122  on the electronic component  120  would not be exposed from the encapsulant. In other embodiments, the frame  130  may include a plurality of L shape sheets  136 , as shown in  FIG. 17 . Each sheet  136  includes connected or adjacent vertical portions  131  and horizontal portions  133 . The distance d 2  between the adjacent two sheets  136  is less than or equal to 1.5 mm, but the present disclosure is not limited thereto. 
     Accordingly, the embodiments of the present disclosure provides a package module packaged in a housing, in which the frame is disposed next to the at least one side of the electronic component, and the encapsulant is filled into the gap between the frame and the electronic component. As a result, the height of the encapsulant covering the electronic component is higher than that of another portion of the encapsulant (e.g. the encapsulant covering the circuit board), and therefore the amount of the encapsulant is saved. 
     Although the present disclosure has been described in considerable details with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.