Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/821,812, filed Aug. 10, 2015, which is a continuation of U.S. patent application Ser. No. 13/163,770, filed Jun. 20, 2011, each of which is herein incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    I. Field of the Invention 
         [0003]    The present invention relates to a packaging structure, and in particularly, to a metallic frame for packaging and making electrical connections. 
         [0004]    II. Description of the Prior Art 
         [0005]    Lead frame is a material for IC package and can be in variety of forms such as QFP, TSOP, SOT or SOJ. The molded semiconductor devices are constructed by assembling and interconnecting a semiconductor device to a lead frame. The structure is often molded with plastic material. A lead frame is made by a metal ribbon with a paddle (also known as a die paddle, die-attach tab, or island) for attaching a semiconductor device thereto and a plurality of leads arranged in a manner such that the leads do not overlap the paddle on which the semiconductor device is to be mounted. 
         [0006]    Conventionally, lead frame is used for die bond of an IC chip. The process flow includes many stages which are wire bond, molding of IC chip, and the tests after trimming or forming. Various products can be made by integrating or packaging the lead frame with other devices such as inductors or capacitors. It&#39;s one of the main packaging processes in the industry due to its easiness, maturity and better reliability. However, such kind of conventional process has many disadvantages including: a. higher cost and more development works of molding devices; b. poor capability in area design which is only in the form of plane so that product size doesn&#39;t shrink; and c. lacking of modular capability as it is only good for packaging a single device. 
         [0007]    Accordingly, the present invention proposes a stack frame and its manufacturing method to overcome the above-mentioned disadvantages. 
       SUMMARY OF THE INVENTION 
       [0008]    One objective of the present invention is to provide a method of forming a stack frame for manufacturing a structure for electrical connections. By removing one or more portions of the metallic substrate, a metallic frame having a plurality of pins is formed. The conductive pattern is formed on the metallic frame to make a plurality of electrical connections to connect with a plurality of pins. Because metallic frame is metallic, it has better performance in heat dissipation and electrical conductance. 
         [0009]    Another objective of the present invention is to provide a method of forming a lead frame for manufacturing a package structure for electrical connections. The conductive pattern is formed on the lead frame to make the electrical connections to the plurality of pins. Because the lead frame is metallic, it has better performance in heat dissipation and electrical conductance. 
         [0010]    One embodiment in the present invention is to form a recess is in the metallic frame and at least one conductive element is bonded in the recess. I/O terminals of a conductive element can be electrically connected to a conductive layer by conventional technology, such as wire bond, gold-ball bond, conductive wires (by film process, printing process, electroplating) or a combination thereof 
         [0011]    The structure can be used in IC package in which a first conductive element is encapsulated mainly in the metallic frame, not molded with plastic material; and a second conductive element can be mounted on the metallic frame by SMT. The first conductive element and the second conductive element can be active elements, such as IC chip, MOSFET, IGBT or diode, or passive elements, such as resistors, capacitors or inductors. The first conductive element and the second conductive element are directly electrically connected to the metallic frame (or pin), so it doesn&#39;t need additional PCB in order to connect them. Moreover, dispensing or gluing are used to replace molding encapsulation for protection of the first conductive element. Therefore, it does not need additional development of molding devices; it can save time and cost; and it&#39;s easier for design. Compared with lead frame and molding in conventional structure of IC package, the structure can make the shortest electrical path for connecting the components so that it can reduce total impedance and increase electrical efficiency. 
         [0012]    Another embodiment of the present invention is to use both top and bottom surfaces of metallic frame to make another structure for electrical connections. 
         [0013]    In one embodiment, a method for forming a conductive structure is disclosed, the method comprising the steps of: forming a metallic frame having a plurality of metal parts separated from each other; forming an insulating layer on the top surface of the plurality of metal parts; and forming a conductive pattern layer on the insulating layer for making electrical connections with at least one portion of the plurality of metal parts. 
         [0014]    In one embodiment, the plurality of metal parts comprise a supporting metal body and a plurality of metal pins adjacent to the supporting metal body, wherein each of the plurality of metal pins is spaced apart from the supporting metal body. 
         [0015]    In one embodiment, the method further comprising forming at least one via in the insulating layer, wherein the conductive pattern layer electrically connects with the plurality of metal pins through the at least one via. 
         [0016]    In one embodiment, wherein forming the metallic frame is by removing one or more portions of a metallic substrate so as to form said gap between each of the plurality of metal pins and the supporting metal body. 
         [0017]    In one embodiment, wherein forming a conductive pattern is performed by a film process. 
         [0018]    In one embodiment, wherein forming a conductive pattern is performed by a thin film process. 
         [0019]    In one embodiment, the method further comprising forming a filling layer to fill gaps between the metal body and the plurality of pins, wherein the filling layer is different from the insulating layer. 
         [0020]    In one embodiment, wherein the insulating layer extends into gaps between the metal body and the plurality of pins. 
         [0021]    In one embodiment, wherein the height of the supporting metal body is the same as the height of each of the plurality of metal pins. 
         [0022]    In one embodiment, the method further comprising the step of: placing a first conductive element having a least one first I/O terminal over the metallic frame, wherein the conductive pattern layer further electrically connects with said at least one first I/O terminal of the second conductive element. 
         [0023]    In one embodiment, the method further comprising the steps of: forming a recess in the supporting metal body; and placing a first conductive element having at least one first I/O terminal in the recess, wherein the conductive pattern layer further electrically connects with said at least one first I/O terminal of the first conductive element. 
         [0024]    In one embodiment, the method further comprising the step of: placing a second conductive element having a least one second I/O terminal over the metallic frame, wherein the conductive pattern layer further electrically connects with said at least one second I/O terminal of the second conductive element. 
         [0025]    In one embodiment, wherein a polymer material comprises photoresist material. 
         [0026]    In one embodiment, wherein the metal substrate is made of at least one of Cu, Ag or Sn. 
         [0027]    In one embodiment, wherein the first conductive element comprises at least one of 
         [0028]    IC chip, MOSFET, IGBT, diode, choke, capacitor or resistor. 
         [0029]    In one embodiment, wherein the first conductive element comprises at least one of 
         [0030]    IC chip, MOSFET, IGBT, diode, choke, capacitor or resistor. 
         [0031]    In one embodiment, wherein the second conductive element comprises at least one of IC chip, MOSFET, IGBT, diode, choke, capacitor or resistor. 
         [0032]    In one embodiment, wherein the metal substrate is disposed on a supporting layer, the method further comprising the steps of: removing the supporting layer after the gaps between the supporting metal body and the plurality of metal pins are filled; and forming a second pad underlying the metallic frame. 
         [0033]    In one embodiment, wherein the top surface of the first conductive element and the top surface of the metallic frame are substantially at the same horizontal level. 
         [0034]    In one embodiment, a top surface of the supporting metal body and a top surface of each of the plurality of metal pins are substantially at the same horizontal level. 
         [0035]    In one embodiment, wherein forming the insulating layer on the top surface of the metallic frame further comprising forming at least one via in the insulating layer, wherein the conductive pattern layer electrically connects with at least one of the plurality of metal pins and the at least one first I/O terminal of the first conductive element via the at least one via. 
         [0036]    In one embodiment, wherein forming the insulating layer on the top surface of the lead frame further comprising forming at least one via in the insulating layer, wherein the conductive pattern layer electrically connects with at least one of the plurality of metal pins and the at least one first I/O terminal of the first conductive element via the at least one via. 
         [0037]    The present invention also discloses forming a filling layer to fill a least one vacancy of the metallic frame. The filling layer can be a polymer material layer which can not only fill vacancies of the metallic frame but also cover the metallic frame. Accordingly, the polymer material layer can also be patterned on the stack frame so that the conductive layer can be contacted with the polymer material layer. As a result, it can reduce the overall process cost. 
         [0038]    The detailed technology and above preferred embodiments implemented for the present invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0039]    The foregoing aspects and many of the accompanying advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings, wherein: 
           [0040]      FIG. 1  is a process flow of a method for manufacturing a structure for electrical connection. 
           [0041]      FIG. 2A  and  FIG. 2B  illustrate a top view of stack frame with no vacancy and a top view of stack frame with at least one vacancy respectively. 
           [0042]      FIG. 2C  and  FIG. 2D  illustrate a schematic cross-sectional view of of stack frame with no vacancy and a schematic cross-sectional view of stack frame with at least one vacancy respectively. 
           [0043]      FIG. 3A  illustrates a schematic cross-sectional view of the structure of stack frame with no vacancy for electrical connections. 
           [0044]      FIG. 3B  illustrates a schematic cross-sectional view of the structure of stack frame with no vacancy and with a recess in which a conductive element is bonded for electrical connections. 
           [0045]      FIG. 3C  illustrates a schematic cross-sectional view of the structure of stack frame with no vacancy for electrical connections by process both on the top surface and the bottom surface of the structure. 
           [0046]      FIG. 3D  illustrates a product structure with at least one first conductive element on the structure in  FIG. 3A . 
           [0047]      FIG. 4A  illustrates a schematic cross-sectional view of the structure of stack frame with at least one vacancy for electrical connections. 
           [0048]      FIG. 4B  illustrates a schematic cross-sectional view of the structure of stack frame with at least one vacancy and with a recess in which a conductive element is bonded for electrical connections. 
           [0049]      FIG. 4C  illustrates a schematic cross-sectional view of the structure of stack frame with at least one vacancy for electrical connections by process on both the top surface and the bottom surface of the structure. 
           [0050]      FIG. 4D  illustrates another schematic cross-sectional view of the structure of stack frame with at least one vacancy for electrical connections. 
           [0051]      FIG. 4E  illustrates a product structure with at least one first conductive element on the structure in  FIG. 4A . 
           [0052]      FIG. 5A  illustrates a sectional view of the package structure of the embodiment of the present invention. 
           [0053]      FIG. 5B  to  FIG. 5J  illustrates a process flow for manufacturing a package structure of the present invention. 
           [0054]      FIG. 5K  illustrates the top view of the package structure in  FIG. 5A . 
           [0055]      FIG. 5L  illustrates the bottom view of the package structure in  FIG. 5A . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0056]    The detailed explanation of the present invention is described as following. The described preferred embodiments are presented for purposes of illustrations and description, and they are not intended to limit the scope of the present invention. 
         [0057]    The invention discloses a method for manufacturing a stack frame. A stack frame means a frame on which something is constructed to combine some more functionality. 
         [0058]    Please refer to  FIG. 1 , a method for manufacturing a stack frame is achieved by the following steps: 
         [0000]    In step  11 , a metallic substrate is provided.
 
In step  12 , a metallic frame having a plurality of pins is formed by removing one or more portions of the metallic substrate.
 
In step  13 , a conductive pattern is formed on the metallic frame to make a plurality of electrical connections to connect with the plurality of pins.
 
         [0059]    In step  11 , the metallic substrate can be made of any conductive material, such as metallic material which includes and is not limited, Cu, Ag, Sn or a combination thereof. In step  12 , the technology for removing one or more portions of the metallic substrate to form a metallic frame having a plurality of pins can be any known method. A metallic frame has a plurality of pins as I/O terminals, and pads are placed underlying pins for external electrical connection. The metallic frame can be a lead frame or any other equivalent structure. In one embodiment, the metallic frame can have no vacancy or at least one vacancy. Appearance or shape of the metallic frame depends on layout of pads via which the pin of the metallic frame is electrically connected to PCB or another conductive element, such as IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor. In step  13 , a conductive pattern is formed on the metallic frame by known techniques, such as film process, printing process, laser drilling or a combination thereof. The conductive pattern comprises a plurality of electrical connections to connect with the plurality of the plurality of pins. In one embodiment, at least one conductive layer is patterned on the metallic frame to make better performance of the electrical connections to the plurality of pins. 
         [0060]      FIG. 2A  and  FIG. 2B  illustrate a top view of metallic frame  31  with no vacancy and a top view of metallic frame  32  with at least one vacancy  33  respectively. Metallic frame having a plurality of pins  34  can be in any suitable appearance or shape for subsequent processing.  FIG. 2C  and  FIG. 2D  illustrate a schematic cross-sectional view of a metallic frame  31  with no vacancy and a schematic cross-sectional view of a metallic frame  32  with a vacancy  33  respectively. In reference to both  FIG. 2A  and  FIG. 2C  together, sections A-A′ in  FIG. 2C  are taken along line A-A′ shown in  FIG. 2A . In reference to both  FIG. 2B  and  FIG. 2D  together, sections B-B′ in  FIG. 2D  are taken along line B-B′ shown in  FIG. 2B . The preferred structures and manufacturing method are described in the following embodiments. 
       First Embodiment 
       [0061]      FIG. 3A  illustrates a schematic cross-sectional view of a structure  100  of stack frame with no vacancy for electrical connections. In one embodiment, the structure  100  includes a metallic frame  101  with no vacancy, a dielectric layer  102  and a conductive layer  103 . The dielectric layer  102  is disposed on the metallic frame  101 . The conducted layer  103  is formed on the dielectric layer  102  and filled into vias which are formed inside of the dielectric layer  102 . The structure  100  can include any other equivalent structure for electrical connections as well; and the structure can be made of any suitable material by any suitable process. In another embodiment, as illustrated in  FIG. 3B , a recess  118  is formed in the metallic frame  101  and a conductive element  111  (e.g., IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor) is bonded in the recess  118  by conventional techniques (e.g., Ag gluing  119 ). There are many different ways to locate the recess, for example, in one embodiment the recess is formed inside of the metallic frame; in another embodiment the recess is formed with one side aligned with one edge of the metallic frame; and in yet another embodiment the recess is formed with two sides aligned with two edges of the metallic frame respectively. In one embodiment, the recess can be formed in the metallic frame which comprises a plurality of sub metallic frames, wherein a plurality of sub metallic frames are joined together. In one embodiment, at least one conductive element is bonded in the recess. I/O terminals of the conductive element  111  can be electrically connected to the conductive layer  103  by conventional technology, such as wire bond, gold-ball bond, conductive wires (by film process, printing process or electroplating) or a combination thereof. In one embodiment, the top surface  112  of the conductive element and the top surface  113  of metallic frame are at the same horizontal level. In yet another embodiment, as illustrated in  FIG. 3C , the process can be performed on both top surface  113  and bottom surface  114  of metallic frame. The features described above can also be applied to the structure in  FIG. 3C . 
         [0062]      FIG. 3D  illustrates a product structure  150  with a first conductive element  105  on the structure  150  in  FIG. 3A . A first pad  104  can be formed on the conductive layer  103  so that a conductive element  105  (e.g., IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor) can be placed on the first pad  104 . A second pad  106  can be formed underlying the pins of the stack frame. The second pad  106  can be made of any conductive material, such as Sn, Ni/Au or the like. The structure  150  can be mounted on PCB or electrically connected to another conductive element (not shown) (e.g., IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor) so that the conductive element  105  can be electrically connected to PCB or another conductive element (not shown) via the conductive path including the first pad  104 , the conductive layer  103 , metallic frame (or pin)  101  and a second pad  106 . It should be noted that the way to make electrical connections varies with different kinds of products and process performed on the metallic frame. It can include many ways and is not limited to the ways described above. It can be readily appreciated by those skilled in the art and thus will not be further described herein. 
       Second Embodiment 
       [0063]      FIG. 4A  illustrates a schematic cross-sectional view of the structure  200  of stack frame with at least one vacancy  221  for electrical connections. In one embodiment, the structure includes a metallic frame  201  with at least one vacancy  221 , a dielectric layer  202  and a conductive layer  203 . The filling layer  222  is filled with a least one vacancy  221  of the metallic frame. The dielectric layer  202  is disposed on the metallic frame  201  and the conducted layer  203  is formed on the dielectric layer  202  and filled into vias which are formed inside of the dielectric layer  202 . The structure  200  can include any other equivalent structure for electrical connections. The structure can be made of any suitable material and can be made by any suitable process. In another embodiment, as illustrated in  FIG. 4B , a recess  218  is formed in the metallic frame  201  and at least one conductive element  211  (e.g., IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor) is bonded in the recess  218  by conventional techniques (e.g., Ag gluing  219 ). There are many different ways to locate the recess, for example, in one embodiment the recess is formed inside of the metallic frame; in another embodiment the recess is formed with one side aligned with one edge of the metallic frame; and in yet another embodiment the recess is formed with two sides aligned with two edges of the metallic frame respectively. In one embodiment, the recess can be formed in the metallic frame which comprises a plurality of sub metallic frames, wherein a plurality of sub metallic frames are joined together. In one embodiment, at least one conductive element is bonded in the recess. I/O terminals of the conductive element  211  can be electrically connected to the conductive layer by conventional technology, such as wire bond, gold-ball bond, conductive wires (by film process, printing process or electroplating) or a combination thereof. In one embodiment, the top surface  212  of the conductive element and the top surface  213  of metallic frame are at the same horizontal level. In yet another embodiment, as illustrated in  FIG. 4C , the process can be performed on top surface  213  and bottom surface  214  of metallic frame. 
         [0064]    Please refer back to  FIG. 3A , there is a structural difference between  FIG. 3A  and  FIG. 4A . The metallic frame of the structure  100  in  FIG. 3A  has no vacancy; whereas the metallic frame of the structure  200  in  FIG. 4A  has at least one vacancy  221  which can be filled by the filling layer  222 . In one embodiment, the filling layer can fill at least one vacancy  202  of the metallic frame  201  and cover the metallic frame  201 . The filling layer  222  includes any suitable material, such as a polymer material or the like. The polymer material includes a photoresist. In one embodiment, underlying the metallic frame is a supporting layer (not shown), such as polyimide film (PI film), which can support the filling layer  222 . At the end of the overall process, the supporting layer can be removed. In one embodiment, supporting layer is not necessary. In one embodiment, please refer to  FIG. 4D , the filling layer and the dielectric layer can be a single layer  223 . In one preferred embodiment, the single layer  223  is a polymer material layer (e.g., photoresist or negative photoresist). The polymer material layer not only can fill the vacancies but also can be patterned on the metallic frame by some known techniques, such as lithography process, laser drilling or the like, so that the conductive layer  203  can be contacted with the polymer material layer. Accordingly, the overall processing cost can be reduced. Furthermore, the features described above in  FIG. 4B  and  FIG. 4D  can also be applied to the structure in  FIG. 4C  as well. 
         [0065]      FIG. 4E  illustrates another product structure  250  with a first conductive element  205  on the structure  200  in  FIG. 4A . A first pad  204  is formed on the conductive layer  203  so that a conductive element  205  (e.g., IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor) can be placed on the first pad  204 . A second pad  206  can be formed underlying the pins of the stack frame. The second pad  206  can be made of any conductive material, such as Sn, Ni/Au or the like. The structure  250  can be mounted on PCB or electrically connected to another conductive element (not shown) (e.g., IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor) so that the first conductive element  205  can be electrically connected to a PCB or another conductive element (not shown) via the conductive path including the first pad  204 , the conductive layer  203 , metallic frame (or pin)  201  and a second pad  206 . It should be noted that the way to make electrical connections varies with different kinds of products and process performed on the metallic frame. It can include many ways and is not limited to the ways discussed above. It can be readily appreciated by those skilled in the art and thus will not be further described herein. 
         [0066]    The following embodiment discloses a package structure and its manufacturing method. In the embodiment, the metallic frame is a lead frame and the lead frame is the main constituent of the package structure. 
       Third Embodiment 
       [0067]      FIG. 5A  illustrates a sectional view of the package structure  300 . The package structure  300  includes a lead frame  301 , a filling layer  306 , a first conductive element  304 , a conductive pattern  312 , a protective layer  311 , a conductive pad  313 , and at least one second conductive element  314 . A lead frame has a plurality of pins  315  which can be in many forms, such as I/O terminals or pads (not shown) which are placed underlying pins  315  for external electrical connection. The appearance or shape of the lead frame depends on the layout of the pads via which the structure  300  is electrically connected to PCB or a third conductive element (not shown), such as IC chip, MOSFET, IGBT, diode, resistor, choke or capacitor. In one embodiment, the lead frame  301  can have no vacancy or at least one vacancy. The structure  300  can include any other equivalent structure for a package structure, and it can be made of any suitable material and manufactured by any suitable process. A lead frame  301  can be made of conductive material, such as Ag, Cu, Sn or a combination thereof. A conductive pattern  312  is formed on the lead frame  301  by some known techniques, such as film process, printing process, laser drilling or a combination thereof. In one embodiment, at least one conductive layer is patterned on the lead frame  301  to make better performance of a plurality of electrical connections to the pins  315 . 
         [0068]    One aspect of structural difference between lead frames lies in whether it has vacancy or not. Besides that, the remaining of the structure of lead frame are almost the same. The preferred structures and manufacturing method in the following description refer to performing the film process on the lead frame which has at least one vacancy. 
         [0069]      FIG. 5B  to  FIG. 5H  illustrate a sectional view of process flow for manufacturing the package structure  300 . 
         [0070]    As illustrated in  FIG. 5B , a recess  303  is formed in the lead frame  301  with at least one vacancy  302 . The recess  303  can be formed by a known technology, such as etching or surface coarsening. There are many different ways to locate the recess, for example, in one embodiment the recess is formed inside of the lead frame; in another embodiment the recess is formed with one side aligned with one edge of the lead frame; and in yet another embodiment the recess is formed with two sides aligned with two edges of the lead frame respectively. In one embodiment, the recess can be formed in the lead frame which comprises a plurality of sub lead frames, wherein a plurality of sub lead frames are joined together. 
         [0071]    Next, as illustrated in  FIG. 5C , a first conductive element  304 , such as IC chip, MOSFET, IGBT or diode, is bonded in the recess  303  by conventional techniques (e.g., Ag gluing  305 ). In one embodiment, at least one first conductive element is bonded in the recess. 
         [0072]    Next, as illustrated in  FIG. 5D , the filling layer  306  is filled into at least one vacancy  302  of the lead frame  301 . In one embodiment, the filling layer can fill at least one vacancy  302  of the lead frame  301  and cover the lead frame  301 . A supporting layer, such as polyimide film (PI film), is attached underlying the lead frame  301  to support the filling layer  306 . At the end of the overall process, the supporting layer can be removed. In one embodiment, supporting layer is not necessary. The filling layer  306  includes any suitable material, such as a polymer material or the like. The polymer material can be a photoresist. In the preferred embodiment, the filling layer  306  is a polymer material layer (e.g., photoresist or negative photoresist). The polymer material layer not only can fill a plurality of vacancies but also can be patterned on the lead frame  301  by known techniques, such as lithography process, laser drilling, so that the conductive pattern  312  can be contacted with the polymer material layer. 
         [0073]    Please refer to  FIG. 5E , a polymer material (e.g., photoresist or negative photoresist) layer  306  is patterned to expose the I/O terminals of the first conductive element  304  by a known process, such as lithography process, laser drilling or the like. A conductive pattern  312 , which will be discussed in next stage, is formed on the lead frame. 
         [0074]    Next, as illustrated in  FIG. 5F  and  FIG. 5I , a thin copper layer  308  is sputtered over the polymer material layer  306 , a portion of pins of the lead frame  315  and I/O terminals of the first conductive element  304 . A thin copper layer  108  and a thick copper layer  310  (shown in  FIG. 50  are combined into a conductive pattern  312  to make two groups of electrical connections. The first group of electrical connections is between a portion of pins of lead frame  315  and I/O terminals of the first conductive element  304 . The second group of electrical connections is between the second conductive element  314  and I/O terminals of the first conductive element  304 . A thin copper layer  308  is used to contact I/O terminals of the first conductive element  304  to reduce the contact resistance between I/O terminals of the first conductive element  304  and the conductive pattern  312 . 
         [0075]    Please continuously refers to  FIG. 5F  and FIG. SI. A photoresist layer  309  (e.g., positive photoresist) is patterned on a portion of thin copper layer  108  to expose the remaining portion of thin copper layer  308 . Then a thick copper layer  310  is formed on the remaining portion of thin copper layer  308  by a known process, such as electroplating. As a result, a thin copper layer  308  and a thick copper layer  310  (shown in  FIG. 50  are combined into a conductive pattern  312  to make two groups of electrical connections described above. 
         [0076]    In one embodiment, I/O terminals of the first conductive element  304  can be electrically connected to the conductive pattern  312  by conventional technology, such as wire bond, gold-ball bond, conductive wires (by film process, printing process, or electroplating) or a combination thereof.  FIG. 5H  and  FIG. 5G  illustrate electrical connections between the I/O terminal of the first conductive element  304  and the conductive pattern  312  by way of wire bonds  316  or gold ball bonds  317 . A gold-ball bond is used to contact I/O terminals of the first conductive element  304  to reduce contact resistance between I/O terminals of the first conductive element  304  and the conductive pattern  312 . 
         [0077]    Next, as illustrated in  FIG. 5J  and  FIG. 5A , the photoresist layer  309  is removed. In one embodiment, the thick copper layer  310  can be trimmed to a suitable thickness. Then, a protective layer  311  is selectively patterned to expose a portion of the conductive pattern  312 . A first pad  313  can be formed on the portion of the conductive pattern  312  by a known process, such as printing solder, to connect with a second conductive element  314 , such as choke, capacitor or resistor. Then a second pad  318  can be formed underlying the lead frame to further connect to PCB. The second pad  318  can be made of any conductive material, such as Sn, Ni/Au or the like.  FIG. 5A  illustrates a product structure  300  of the embodiment of the present invention. 
         [0078]      FIG. 5K  and  FIG. 5L  illustrate the top view and bottom view of the product structure  300  in  FIG. 5A . In reference to both  FIG. 5A  and  FIG. 5K  together, sections C-C′ in  FIG. 5A  are taken along line C-C′ shown in  FIG. 5K . In reference to both  FIG. 5A  and  FIG. 5L  together, sections C-C′ in  FIG. 5A  are taken along line C-C′ shown in  FIG. 5L . As illustrated in  FIG. 5K , the top view of the product structure  300  mainly includes a lead frame  301  and a second conductive element  314  in  FIG. 5A . As illustrated in  FIG. 5L , the bottom view of the product structure  300  mainly includes a lead frame  301  and a second pad  318  in  FIG. 5A . The first conductive element (not shown)  304  is embedded in the product structure  300 . It should be noted that the way to make electrical connections varies with different kinds of products and process performed on the metallic frame. It can include many ways and is not limited to the ways discussed above. It can be readily appreciated by those skilled in the art and thus will not be further described herein. 
         [0079]    It follows from description of the above embodiments that the structure in the present invention and the method for manufacturing the same can offer many advantages including: 1. Better performance of heat dissipation and electrical conductance as the metallic frame is metallic. 2. Smaller size by forming a recess in the metallic frame and using conventional technology and process, such as film process, printing process or electroplating, to connect all the conductive elements by a conductive pattern with the metallic frame. 3. Versatile applications including active devices such as IC chip, MOSFET, IGBT or diode, or passive devices such as resistors, capacitors or inductors. 
         [0080]    The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.

Technology Category: 5