Abstract:
A power semiconductor device comprises a lead frame unit, a control die, a first MOSFET die and a second MOSFET die, wherein the lead frame unit comprises at least a die paddle for mounting the first and second MOSFET dies, a first pin and a second pin for connecting to top electrodes of the first and second MOSFET dies, a first row of carrier pins and a second row of carrier pins disposed in-line with the first and second pins respectively for the control die to mount thereon.

Description:
This Patent Application is a Divisional (DIV) Application, thus claiming the priority, of a co-pending application Ser. No. 13/913,717 filed on Jun. 10, 2013 by a common inventor of this Application. The Disclosure made in the patent application Ser. No. 13/913,717 is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention generally relates to a power management device, particularly relating to a power control device including a high-side MOSFET, a low-side MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) and a control integrated circuit (IC) and a preparation method thereof. 
     DESCRIPTION OF THE RELATED ART 
     Due to large power consumption of semiconductor chips in a power control device such as a DC-DC application, the source electrode or the drain electrode of the semiconductor power chip often needs to have good heat dissipation; thus, part of lead frame is exposed from a plastic package body to improve the thermal performance. For example, as shown in  FIG. 1 , a DC-DC converter  10  includes a high-side MOSFET  11 , a low-side MOSFET  13  and a control IC  12 , where the control IC  12  outputs a PWN or PFM signal to MOSFET  11  and MOSFET  13  and receives feedback signals thereof; therefore, some electrode pads of the MOSFET  11  and the MOSFET  13  is electrically connected to I/O pad of the control IC  12  through a plurality of bonding wires. The MOSFET  11  and the MOSFET  13  are respectively attached on a die paddle  21  and a die paddle  23  separated from each other, where the source of the MOSFET  11  is connected to the paddle  23  through a metal clip  15  and the source of the MOSFET  13  is connected with a pin  24  through a metal clip  16 , while the control IC  12  is attached on separate die paddle  22 . The bottom surface of the die paddle  21  and the die paddle  23  are exposed from the plastic package body (not shown) as a terminal for electrical contact with an external circuit and for heat dissipation. The die paddle  21 , the die paddle  22  and the die paddle  23  take large areas, which lead to expensive cost and device big size. US patent publication US2012061813A1 discloses a DC-DC converter, in which the high-side MOSFET and low-side MOSFET are located on two separate die paddles arranged side by side. However, the low-side MOSFET is completely overlapped on the high-side MOSFET and the control device; thus, the height of the bonding wire connecting the high-side MOSFET and the control device must be well controlled to avoid the contact between the bonding wire and the low-side MOSFET. In addition, the heat dissipation of the high-side MOSFET and the low-side MOSFET of this device is poor. 
     It is within this context that embodiments of the present invention arise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       As shown in attached drawing, the embodiment of the invention is more sufficiently described. However, the attached drawings are only used for explaining and illustrating rather than limiting the range of the invention. 
         FIG. 1  is a top view structure of the conventional DC-DC converter  10 . 
         FIGS. 2A-2H  are schematic diagrams illustrating a process forming the power control device of the present invention. 
         FIGS. 3A-3E  are schematic diagrams illustrating a process forming the power control device with a recessed area formed on the die paddle. 
         FIGS. 4A-4C  are schematic diagrams illustrating a process forming the power control device with a recessed area formed on the die paddle and the back surface of the metal clip exposed from the top surface of the plastic package body. 
         FIGS. 5A-5D  are schematic diagrams illustrating a process forming the power control device with a lead frame unit comprising a bypass pin. 
         FIG. 6A  is a schematic diagram of the power control device comprising flipped control die and bonding wires. 
         FIG. 6B  is a schematic diagram of the power control device comprising non-flipped control die and bonding wires. 
         FIGS. 7A-7D  are schematic diagrams illustrating a process forming the power control device utilizing two separate die paddles. 
         FIG. 8A  is a schematic diagram of the power control device with the lead frame comprising two separate die paddles and the bypass pin. 
         FIG. 8B  is a schematic diagram of the power control device having two separate die paddles and the bonding wire. 
         FIG. 8C  is a schematic diagram of the power control device having two separate die paddles and non-flipped control die. 
         FIGS. 9A-9G  are schematic diagrams illustrating a process forming the power control device with the lead frame unit comprising one die paddle and non-flipped low-side MOSFET. 
         FIG. 10A  is a schematic diagram of the power control device including flipped low-side MOSFET and the lead frame unit comprising the bypass pin. 
         FIG. 10B  is a schematic diagram of the power control device including flipped low-side MOSFET and the bonding wire. 
         FIGS. 11A-11B  are schematic diagrams of the power control device including flipped low-side MOSFET and non-flipped control die. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 2A  is a top view of a lead frame unit comprising a die paddle  110  in a rectangular shape regularly and a first pin  111  and a second pin  112 , a first row of carrier pins  113  and a second row of carrier pins  114 . For the convenience to describe the position of the components of the lead frame unit, an X-Y-Z Cartesian coordinate system is defined in  FIG. 2A . The die paddle  110  includes a first transverse edge  110   a  and a second transverse edge  110   b  opposite to each other, and a first longitudinal edge  110   c  and a second longitudinal edge  110   d  opposite to each other. The first pin  111  includes a strip-type bonding area  111   a  adjacent and extending along the first transverse edge  110   a  and external pins  111   b  perpendicular to the bonding area  111   a  and extending along the direction away from the die paddle  110 . The second pin  112  includes a strip-type bonding area  112   a  adjacent and extending along the second transverse edge  110   b  and external pins  112   b  perpendicular to the bonding area  112   a  and extending along the direction away from the die paddle  110 . 
     Each of the first row of carrier pins  113  and second row of carrier pins  114  includes a plurality of carrier pins arranged in parallel to each other with a distance between two adjacent pins either equal or unequal. The first row of the carrier pins  113  and the second row of the carrier pins  114  are positioned at the same side of and parallel to the second longitudinal edge  110   d  of the die paddle  110 , where the carrier pins of the first row of carrier pins  113  extend in Y direction from an extension of the first pin  111  towards a center line  280  between the first transverse edge  110   a  and the second transverse edge  110   b  , and the carrier pins in the second row of carrier pins  114  extend from an extension of the second pin  112  towards the center line  280 . The die paddle  110  also includes a connecting part  115   a  at the corner of the first transverse edge  110   a  and the second longitudinal edge  110   d  for connecting the die paddle  110  to the innermost carrier pin of the first row of carrier pins  113  closest to the second longitudinal edge  110   d.    
     As shown in  FIG. 2B , a first die  101  and a second die  102  are firstly attached on the top surface of the die paddle  110  side by side, where the first die  101  is close to the first transverse edge  110   a  and the second die  102  is close to the second transverse edge  110   b . A control die  103  is flipped and attached on the first row of carrier pins  113  and the second row of carrier pins  114  and partially overlaps on side portions of the first die  101  and the second die  102  close to the second longitudinal edge  110   d.    
     As shown in  FIG. 2C , the first die  101  is a high-side P- type channel MOSFET, the second die  102  is a low-side N-type channel MOSFET. A first electrode  101   a , for example a source electrode, and a second electrode  101   b , for example a gate electrode, are arranged at the front surface of the first die  101 , and a third electrode, for example a drain electrode, is formed by a metal layer at the back surface of the first die  101  (not shown), where the third electrode is attached on the top surface of the die paddle  110  through a conductive adhesive. Similarly, a first electrode  102   a , for example a source electrode, and a second electrode  102   b , for example a gate electrode, are arranged at the front surface of the second die  102 , and a third electrode, for example a drain electrode, is formed by a metal layer at the back surface of the second die  102   a  (not shown), where the third electrode is attached on the top surface of the die paddle  110  through a conductive adhesive. 
       FIG. 2F  is a cross sectional schematic diagram along the line B 1 -B 1  in  FIG. 2D . As shown in  FIG. 2F , each carrier pin of the first row of carrier pins  113  comprises an upper pin  113   a  and a lower pin  113   b  connected together with the plane of upper pin  113   a  higher than the plane of the lower pin  113   b . Similarly, each carrier pin of the second row of carrier pins  114  comprises an upper pin  114   a  and a lower pin  114   b . The top surfaces of the upper pins  113   a  and  114   a  need to be coplanar with the respective front surface of the first die  101  and the second die  102 . 
     For the sake of the clarity, the control die  103  is drawn transparently in  FIG. 2C , with a metal bump  201  deposited on each electrode pad, similar as the electrode pad  103   a  shown in  FIG. 6B , formed at the front surface of the control die  103 . The metal bumps can be solder ball and the likes. The metal bumps  201  arranged on the electrode pads close to the edges of two opposite sides of the control die are aligned with and attached onto the corresponding upper pins  113   a  and  114   a  respectively. The control die  103  is further mounted to partially overlap on side portions of the first die  101  and the second die  102 , where metal bumps  201  deposited on the electrode pads at the front surface of the control die  103  closed to the edge overlapping with the first die  101  and the second die  102  are aligned with and electrically connected with the first electrode  101   a  and of the first die  101  and the first electrode  102   a  of the second die  102  respectively. As an option, the second electrodes  101   b  and  102   b  of the first and second dies  101  and  102  may be aligned and connected to additional electrode pads of control die  103  through metal bumps  201 . As described above, the top surfaces of the upper pins  113   a  and  114   a  and the respective front surfaces of the first die  101  and the second die  102  are coplanar, as such the control die  103  is attached onto the upper pins  113   a  and  114   a  and the respective front surfaces of the first die  101  and the second die  102  horizontally without slanting, which avoids poor soldering joints of the metal bumps. 
     As shown in  FIG. 2D , a first metal clip  211  is mounted on the front surface of the first die  101  and the bonding area  111   a  of the first pin  111  via an adhesive, and a second metal clip  212  is mounted on the front surface of the second die  102  and the bonding area  112   a  of the second pin  112 .  FIG. 2E  is a cross sectional schematic diagram along the line A 1 -A 1  in  FIG. 2D . As shown in  FIG. 2E , the first die  101  and the second die  102  are attached on the die paddle  110  through a conductive adhesive  215 . The first metal clip  211  and the second metal clip  212  are bridge-type clips able to attach on the dies and the pins located on the planes with different heights. The first metal clip  211  comprises a first part  211   b  (bridge part), a second and a third parts  211   a  and  211   c  (valley parts) connected at two sides of the first part  211   b . The first part  211   b , the second part  211   a  and the third part  211   c  locate on three planes with different heights compared to the plane of the lead frame unit, where the first part  211   b  is highest and the second part  211   a  is lowest. The second part  211  a is attached on the top surface of the bonding area  111   a  of the first pin  111 , and the third part  211  c is attached on the first electrode  101   a  of the first die  101  via an adhesive. Similarly, the second metal clip  212  also comprises a first part  212   b  and a second and a third parts  212   a  and  212   c  connected at two sides of the first part  212   b  respectively. The second part  212   a  is attached on the top surface of the bonding area  112   a  of the second pin  112 , and the third part  212   c  is attached on the first electrode  102   a  of the second die  102 .  FIG. 2G  is a cross sectional schematic diagram along the line C 1 -C 1  in  FIG. 2D  showing the structure of the connecting part  115   a  positioned at the second longitudinal edge  110   d  close to the first row of carrier pins  113  for connecting the die paddle  110  to the innermost carrier pin  113 - 1  with the connecting part  115   a  is thinner than the die paddle  110  and the carrier pins  113 . 
     As shown in  FIG. 2H , which shows a bottom view of the power control device, plastic package materials, such as epoxy resin and the like, is deposited to form a plastic package body  225  for encapsulating the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the first metal clip  211  and the second metal clip  201  and the metal bumps  201 , where the bottom surface of the lower pins  113   b  and  114   b , the bottom surface of the die paddle  110 , and the respective bottom surface of the first pin  111  and the second pin  112  are exposed from the bottom surface of the plastic package body  225 . In this embodiment, the top surface of the first die  101 , the second die  102 , the control die  103 , the first metal clip  211 , the second metal clip  212 , and the metal bumps  201  are all completely encapsulated by the plastic package body  225  (not shown). 
     As shown in  FIGS. 2G-2H , the connecting part  115   a  between the die paddle  110  and the carrier pin  113 - 1  is thinner than the die paddle  110  and the carrier pin  113 - 1 , as such the connecting part  115  is also completely encapsulated inside the plastic package body  225 . Alternatively, the connecting part  115   a  can have the same thickness as the die paddle  110  and the carrier pin  113 - 1 , thus the bottom surface of the connecting part  115   a  can be exposed from the bottom surface of the plastic package body  225  (not shown). 
       FIG. 3A  is a top view of an alternative lead frame unit according to another embodiment of the present invention. The die paddle shown in  FIG. 3A  is similar with that shown in  FIG. 2A  except that a recessed area  1100  roughly in rectangular shape is formed on the top surface of the die paddle  110  by etching or stamping and each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114  is of a strip-type structure. The depth of the recessed area  1100  can be adjusted, so that the front surfaces of the first die  101 , the second die  102 , after attached on the recessed area  1100  of the die paddle  110 , and each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114  are coplanar as shown in  FIG. 3C  that is a cross sectional schematic diagram along the line A 2 -A 2  in  FIG. 3B . In this embodiment, as shown in  FIG. 3D  that is a cross section schematic diagram along line B 2 -B 2  in  FIG. 3B , the control die  103  is flipped and mounted on the first row of carrier pins  113  and the second row of carrier pins  114  and partially overlapped with side portions of the first die  102  and the second die  103 , where some metal bumps  201  formed on electrode pads positioned close to two opposite edges at the front surface of the control die  103  is aligned with and electrically connected with the first electrode  101   a  and the second electrode  101   b  at the front surface of the first die  103  and the first electrode  102   a  and the second electrode  102   b  at the front surface of the second die  102 , while the remaining of the metal bumps  201  of the control die  103  are aligned with and electrically connected with each carrier pin of the first row of carrier pins  113  and the second row of the carrier pins  114 . As shown in  FIG. 3C , both the first die  101  and the second die  102  are attached on the recessed area  1100  of the die paddle  110  via an adhesive  215 . In this embodiment, as shown in  FIG. 3E  that is a bottom view of the device package, the bottom surface of each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114  is exposed from the bottom surface of the plastic package body  225 , while the first die  101  and the second die  102 , the control die  103 , the first metal clip  211  and the second metal clip  212  and the metal bumps  225  are completely encapsulated inside the plastic package body  225  (not shown). 
     In another embodiment as shown in  FIG. 4A , a first metal clip  2110  and a second metal clip  2120  are not a bridge-type clip. As shown in  FIG. 4B , which is a cross sectional schematic diagram along the line A 3 -A 3  in  FIG. 4A , the first metal clip  2110  comprises a first part  2110   b  and a second part  2110   a  connected at one side of the first part  2110   b , where the plane of the first part  2110   b  is higher than that of the second part  2110   a , and a third part  2110   c  connected at the other side of the first part  2110   b , extending downward and attached on the first electrode  101   a  of the first die  101 , while the second part  2110   a  is attached on the bonding area  111   a  of the first pin  111  by the adhesive  215 . The second metal clip  2120  comprises a first part  2120   b  and a second part  2120   a  connected at one side of the first part  2120   b  and a third part  2120   c  connected at the other side of the first part  2120   b , extending downward and attached on the first electrode  102   a  of the second die  102  while the second part  2120   a  is attached on the bonding area  112   a  of the second pin  112  by the adhesive  215 . Due to the factors of preparation technology, for example punching or stamping, the first part  211   b  (or  212   b ) of the first bridge metal clip  211  (or the second bridge metal clip  212 ) shown in  FIG. 3B  is not completely flat, the top surface of the first part  211   b  (or  212   b ) cannot be exposed from the plastic package body  225 ; thus, the first metal clip  211  (or the second metal clip  212 ) is often encapsulated by the plastic package body  225 . In this embodiment, the top surfaces of the first part  2110   b  and the first part  2120   b  of the first and second metal clips  2110  and  2120  respectively are completely flat so they can be exposed from the top surface of the plastic package body  225  as shown in  FIG. 4C  that is a top view of the device package. Alternatively, if the top surfaces of the first parts  211   b  and  212   b  of the metal clips  211  and  212  are absolutely flat surfaces, the first parts  211   b  and  212   b  can also be exposed from the top surface of the plastic package body  225 . The cross section along the line B 3 -B 3  in  FIG. 4A  is the same as that in  FIG. 3D , so that the back surfaces of the flipped control die  103  and the respective top surface of the first part  2110   b  and the first part  2120   b  can be coplanar; thus, the back surfaces of the flipped control die  103  can also be exposed from the top surface of the plastic package body  225  for further improvement of the heat dissipation of the power device. In this embodiment, the bottom surface of each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114 , the bottom surface of the die paddle  110 , and the respective bottom surface of the first pin  111  and the second pin  112  are exposed from the bottom surface of the plastic package body  225 , which is similar as that shown in  FIG. 3E . Alternatively, the first metal clip  2110 , the second metal clip  2120  and the control die  103  can also be completely covered by the plastic package body  225 . 
     In an embodiment as shown in  FIG. 5A , the length L 1  of the first pin  111  extending along the first transverse edge  110   a  is less than the length L 2  of the first transverse edge  110   a  and the length L 3  of the second pin  112  extending along the second transverse edge  110   b  is less than the length L 4  of the second transverse edge  110   b , thus the lead frame unit also includes a first bypass pin  121  and a second bypass pin  122 . The first bypass pin  121  is positioned side by side with the first pin  111 , close to the first transverse edge  110   a  and between the innermost carrier pin  113 - 1  of the first row of carrier pins  113  and the first pin  111  and is connected with the innermost carrier pin  113 - 1  by a connecting part  115   c  with the thickness of the connecting part  115   c  less than or the same with that of the first bypass pin  121  and the carrier pin  113 - 1 . Similarly, the second bypass pin  122  is positioned side by side with the first pin  112 , close to the second transverse edge  110   b  and between an innermost carrier pin  114 - 1  of the second row of carrier pins  114  and the second pin  112  and is connected with the innermost carrier pin  114 - 1  by a connecting part  115   d  with the thickness of the connecting part  115   d  either less than or the same as that of the second bypass pin  122  and the carrier pin  114 - 1 . In  FIG. 5A , the third electrodes of the first die  101  and the second die  102  at the back surfaces are attached on the top surface of the die paddle  110 . The first electrode  101   a  of the first die  101  is electrically connected with the first pin  111  through the first metal clip  211 , and the first electrode  102   a  of the second die  102  is electrically connected with the second pin  112  through the second metal clip  212 . The control die  103  is flipped and attached on the first row of carrier pins  113  and the second row of carrier pins  114 . In this embodiment, the control die  103  does not overlaps with the first die  101  and the second die  102  and the metal bumps  201  deposited on electrode pads at the front surface and close to two opposite edges of the control die  103  are aligned with and electrically connected to the carrier pins of the first row of carrier pins  113  of the second row of carrier pins  114  respectively. In  FIG. 5A , the die paddle is mechanically and electrically connected with any carrier pin of the first row of carrier pins  113  or second row of carrier pins  114  excepting the innermost carrier pin  113 - 1  or  114 - 1  by an L-shaped connecting structure  117 , for example the carrier pin  114 - 2  positioned adjacent to the innermost carrier pin  114 - 1  in the second row of carrier pins  114 . The connecting structure  117  comprises a transversely section  117   b  and a longitudinal section  117   a  connected together and positioned in the same plane. As shown in  FIGS. 5C-5D , which is cross sectional schematic diagrams along lines E 1 -E 1  and E 2 -E 2  of  FIG. 5A  respectively, one end of the transversely section  117   b  is connected with the second longitudinal edge  110   d  of the die paddle  110  and one end of the longitudinal section  117   a  is connected with the carrier pin  114 - 2 . The connecting structure  117  is usually thinner than the die paddle  110  and the carrier pin  114 - 2 , as shown in  FIGS. 5C-5D , thus the connecting structure  117 , after completing the plastic package process, will be encapsulated in the plastic package body  225 . Alternatively, the connecting structure  117  may have same thickness as the die paddle  110  and the carrier pin  114 - 2 , thus, the bottom surface of the connecting structure  117  will be exposed from the bottom surface of the plastic package body  225  (not shown). 
     In this embodiment, the control die  103  is electrically connected with the second electrode  101   b  at the front surface of the first die  101  via the bypass pin  121 , which is connected with the innermost pins  113 - 1  by the connecting parts  115   c , by a conductive structure  311 . Similarly, the control die  103  is electrically connected with the second electrode  102   b  at the front surface of the second die  102  via the bypass pin  122 , which is connected with the innermost pins  114 - 1  via a connecting part  115   d , by a conductive structure  312 . The conductive structures  311  and  312  can be metal clips, conductive bands or bonding wires, and the likes.  FIG. 5B  is a cross sectional schematic diagram along the line D 2 -D 2  in  FIG. 5A . As shown in  FIG. 5B , the conductive structures  311  and  312  are bridge metal clips. The bridge clip  311  includes second and third parts  311   a  and  311   c  connected at two sides of the first part  311   b , where the third part  311   c  is mounted on the second electrode  101   b  at the top surface of the first die  101  and the second part  311   a  is mounted on the top surface of the first bypass pin  121 . Similarly, the bridge clip  312  includes second and third parts  312   a  and  312   c  connected at two sides of the first part  312   b , where the third part  312   c  is mounted on the second electrode  102   b  at the top surface of the second die  102  and the second part  312   a  is mounted on the top surface of the bypass pin  122 . After plastic package process, the bottom surfaces of the die paddle  110 , the first pin  111  and the second pin  121 , the first bypass pin  121  and the second bypass pin  122 , and the bottom surface of each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114  are exposed out of the bottom surface of the plastic package body  225 , while the first die  101 , the second die  102 , the control die  103 , the first metal clip  211 , the second metal clip  212 , the metal bumps  201  and conductive structures  311  and  312  are completely encapsulated inside the plastic package body  225 . 
     In  FIG. 6A , the first die  101  and the second die  102  are firstly attached on the top surface of the die paddle  110 , where the third electrodes at the respective back surfaces of the first die  101  and the second die  102  are attached on the top surface of the die paddle  110 . The control die  103  is flipped and attached on the first row of carrier pins  113  and the second row of carrier pins  114 . The first electrode  101   a  of the first die  101  is electrically connected with the first pin  111  through the first metal clip  211  and the first electrode  102   a  of the second die  102  is electrically connected with the second pin  112  through the first metal clip  212 . The control die  103  does not overlap the first die  102  and the second die  103  and the metal bumps  201  arranged on certain pads positioned close to two opposite edges of the control die  103  are aligned with and electrically connected with the carrier pins of the first row of carrier pin  113  and the second row of the carrier pins  114  respectively. 
     The second electrode  101   b  at the front surface of the first die  101  is electrically connected with any carrier pin of the first row of carrier pins  113  with a bonding wire  119 , preferably to the innermost carrier pin  113 - 1  for a shortest length of the bonding wire  119 . Similarly, the second electrode  102   b  at the front surface of the second die  102  is electrically connected with any carrier pin of the second row of carrier pins  114 . The top surface of the die paddle  110  is electrically connected with any the carrier pin of the second row of carrier pins  114 , which is not connected with the second electrode  102   b  of the second die  102 , through the bonding wire  119 ; for example, the second electrode  102   b  is electrically connected with the innermost carrier pin  114 - 1 , thus the die paddle  110  is electrically connected with the carrier pin  114 - 2  adjacent to the carrier pin  114 - 1  for a shortest bonding wire  119 . After the plastic package process, the bottom surface of the substrate  110 , the first pin and the second pin and the bottom surface of each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114  is exposed from the bottom surface of the plastic package body  225 , while the first die  101 , the second die  102 , the control die  103 , the first metal clip  211  and the second metal clip  212 , the metal bumps  201  and the bonding wires  119  are completely encapsulated inside the plastic package body  225 . 
     In another embodiment as shown in  FIG. 6B , the control die  103  is attached on the first row of carrier pins  113  and the second row of carrier pins  114  without flipping thus the back surface of the control die  103  is attached on the first row of carrier pins  113  and the second row of carrier pins  114 . In addition, the control die  103  also does not overlap the first die  102  and the second die  103 . The second electrode  101   b  of the first die  101 , the second electrode  102   b  of the second die  102  and the top surface of the die paddle  110  are electrically connected with the corresponding electrode pads  103   a , without a metal bump  201  formed on the electrode pad  103   a , at the front surface of the control die  103  by a bonding wire  119  respectively. The other pads  103   a , which are not connected to the second electrodes  101   b  and  102   b  and the die paddle  110 , positioned close to two opposite edges of the control die  103  are electrically connected with the top surface of corresponding carrier pins of the first row of carrier pins  113  and the second row of carrier pins  114  respectively. In order to shorten the length of the bonding wire  119 , the electrode pads  103   a  connected to the second electrodes  101   b  and  102   b  and the die paddle  110  are preferably positioned close to the edge of the control die  103  that is close to the die paddle  110 . After plastic package process, the bottom surfaces of the die paddle  110 , the first pin and the second pin and the bottom surface of each carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114  are exposed from the bottom surface of the plastic package body  225 , while the first die  101  and the second die  102 , the control die  103 , the first metal clip  211 , the second metal clip  212 , and the bonding wires  119  are completely encapsulated inside the plastic package body  225 . 
     In the embodiments shown in  FIGS. 5A ,  6 A and  6 B, the first die  101  is a vertical P-type channel MOSFET and the second die  102  is a vertical N-type channel MOSFET. The first electrode  101   a  is a source electrode and the second electrode  101   b  is a gate electrode. The third electrode at the back surface of the first die  101  is a drain electrode formed by a metal layer (not shown). Similarly, the first electrode  102   a  is a source electrode and the second electrode  102   b  is a gate electrode. The third electrode at the back surface of the second die  102  is a drain electrode formed by a metal layer. 
     In another embodiment, as shown in  FIG. 7A , the lead frame unit includes a first die paddle  110 - 1  and a second die paddle  110 - 2 , for example in rectangular shape, adjacent to each other, where the first pin  111  and the first row of carrier pins  113  are positioned close to the first die paddle  110 - 1  while the second pin  112  and the second row of carrier pins  114  are positioned close to the second die paddle  110 - 2 . The first die paddle  110 - 1  includes two opposite first and second transverse edges  110 - 1   a  and  110 -lb and two opposite first and second longitudinal edges  110 - 1   c  and  110 - 1   d . Similarly, the second die paddle  110 - 2  includes two opposite first and second transverse edges  110 - 2   a  and  110 - 2   b  and two opposite first and second longitudinal edges  110 - 2   c  and  110 - 2   d . The first die paddle  110 - 1  and the second die paddle  110 - 2  are arranged side by side with the first transverse edge  110 - 2   a  of the second die paddle  110 - 2  close to the second transverse edge  110 - 1   b  of the first die paddle  110 - 1 . Preferably, the second longitudinal edge  110 - 1   d  is substantially aligned with the second longitudinal edge  110 - 2   d , and the first longitudinal edge  110 - 1   c  is substantially aligned with the second longitudinal edge  110 - 2   c.    
       FIG. 7C  is a cross sectional schematic diagram along the line A 4 -A 4  in  FIG. 7B . Referring to  FIGS. 7A ,  7 B and  7 C, the first pin  111  is close to the first transverse edge  110 - 1   a  of the first die paddle  110 - 1 , and the strip-type bonding area  111   a  of the first pin  111  extends along the first transverse edge  110 - 1   a  of the first die paddle  110 - 1 , while the second pin  112  is close to the second transverse edge  110 - 2   b  of the second die paddle  110 - 2  and the strip-type bonding area  112   a  of the second pin  112  extends along the second transverse edge  110 - 2   a  of the second die paddle  110 - 2 . Furthermore, the first row of carrier pins  113  are positioned along the side of the second longitudinal edge  110 - 1   d  of the first die paddle  101 - 1  with each carrier pin of the first row of carrier pins  113  being parallel to the second longitudinal edge  110 - 1   d  of the first die paddle  110 - 1  and longitudinally extending from the first pin  111  to a transverse scribe line  380  between the first die paddle  110 - 1  and the second die paddle  110 - 2 . The second row of carrier pins  114  are positioned along the side of the second longitudinal edge  110 - 2   d  of the second die paddle  110 - 2  with each carrier pin of the second row of carrier pins  114  being parallel to the second longitudinal edge  110 - 2   d  of the second die paddle  110 - 2  and longitudinally extending from the second pin  112  to the transverse scribe line  380 . The first die  101  is attached on the top surface of the first die paddle  110 - 1  and the second die  102  is attached on the top surface of the second die paddle  110 - 2 , where the third electrodes at the back surfaces of the first die  101  and the second die  102  are directly attached on the top surface of the first die paddle  110 - 1  and the second die paddle  110 - 2  respectively, while the control die  103  is flipped and attached on the first row of carrier pins  113  and the second row of carrier pins  114 . 
     As shown in  FIG. 7A , the second pin  112  and the innermost carrier pin  114 - 1  are connected together with a connecting part  115   b . Similar to  FIG. 2F , each carrier pin of the first row of carrier pins  113  comprises an upper pin  113   a  and a lower pin  113   b  and each carrier pin of the second row of carrier pins  114  comprises an upper pin  114   a  and a lower pin  114   b , where the top surfaces of the upper pins  113   a  and  114   a  of all carrier pins are coplanar with the front surfaces  101   a  and  102   a  of the first die  101  and the second die  102  respectively after the dies are mounted on the first and second die paddles, as shown in  FIG. 7B , thus the control die  103  is flipped and attached on the first row of carrier pins  113  and the second row of carrier pins  114  and also is partially overlapped on the first die  101  and the second die  102   a  with the plurality metal bumps  201  deposited on the plurality of electrode pads at the front surface of the control die  103  at the overlapping area being respectively aligned with and mounted on the first electrode  101   a  and the second electrode  101   b  at the front surface of the first die  101  and the first electrode  102   a  and the second electrode  102   b  at the front surface of the second die  102 . The other metal bumps  201  deposited on the remained electrode pads of the control die  103  are respectively aligned with and electrically connected to each corresponding upper pin of the first row of carrier pins  113  and the second row of carrier pins  114 , which is similar as that shown  FIG. 2C . However, the control die  103  cannot be contacted with the metal clip  250 . In  FIGS. 7B-7C , the first electrode  101   a  of the first die  101  and the first electrode  102   a  of the second die  102  are electrically connected with the second pin  112  through a metal clip  250  that has a wave shape including a plurality of first parts  250   b  and  250   d  (bridge part) and a plurality of second parts  250   a ,  250   c  and  250   e  (valley part), where the plane of the first part  250   b  or  250   d  is higher than that of the second part  250   a ,  250   c  or  250   e . The second parts  250   c  and  250   e  of the metal clip  250 , which are mounted on the first electrode  101   a  of the first die  101  and the first electrode  102   a  of the second die  102 , are coplanar, while the second part  250   a  at one end of the metal clip  250 , which is mounted on the second pin  112 , is located in a plane lower than that of the second parts  250   c  and  250   e . The first part and the second part are alternatively formed in a metal clip  250  with both sides of each first part being connected with two second parts and vice versa. As shown in  FIG. 7C , the second part  250   a  is mounted on the top surface of the bonding area  112   a  of the second pin  112  with a conductive adhesive, while the second parts  250   c  and  250   e  are mounted on the first electrodes  102   a  and  102   a  of the second die  102  and first die  101  respectively with an adhesive. 
     In addition, as shown in  FIGS. 7A-7C , the first die paddle  110 - 1  includes a connecting part  116  extending from the first transverse edge  110 - 1   a  of the first die paddle  110 - 1  to the first pin  111  and connecting to the first pin  111 . The connecting part  116  is preferably thinner than the first die paddle  110 - 1  for clamping with the plastic package body  225 .  FIG. 7D  is a bottom view of the power control device of  FIGS. 7A-7C  after the packaging process. As shown in  FIG. 7D , the power control device further comprises a plastic package body  225  that encapsulates the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  250  and the metal bumps  201  with the bottom surfaces of the lower pins  113   b  and  114   b , the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the bottom surface of the first pin  111  and the second pin  112  being exposed from the bottom surface of the plastic package body  225 . 
     In another embodiment as shown in  FIG. 8A , the control die  103  is flipped and attached on the first row of carrier pins  113  and the second row of carrier pins  114 , but not overlapped with the first die  101  and the second die  102 . The metal bumps  201  formed on the electrode pads at two opposite edges of the control die  103  are respectively aligned with and attached on the corresponding carrier pins of the first row of carrier pins  113  and the second row of carrier pins  114  carrier. The first die paddle  110 - 1  does not include the connecting part  116  as that shown in  FIG. 7A , thus it is separated from the first pin  111 . Similar as  FIG. 5A , the length of the first pin  111  is less than the length of the first transverse edge  110 - 1   a  of the first die paddle  110 - 1  and the length of the second pin  112  is less than the length of the first transverse edge  110 - 2   b  of the second die paddle  110 - 2 . As such, the lead frame unit further includes the first bypass pin  121  positioned between the innermost carrier pin  113 - 1  of the first row of carrier pins  113  and the first pin  111  close to the first transverse edge  110 - 1   a  of the first die paddle  110 - 1 , which includes a connecting part  115   c  connecting to the carrier pin  113 - 1 . Similarly, the lead frame unit further includes the second bypass pin  122  positioned between the innermost carrier pin  114 - 1  of the second row of carrier pins  114  and the second pin  112  close to the second transverse edge  110 - 2   b  of the second die paddle  110 - 2 , which includes a connecting part  115   d  connecting to the carrier pin  114 - 1 . The second electrode  101   b  at the front surface of the first die  101  is electrically connected with the first bypass pin  121  through a conductive structure  311  and the second electrode  102   b  at the front surface of the second die  102  is electrically connected with the second bypass pin  122  through a conductive structure  312 . In this embodiment, the second pin  112  is electrically connected with any carrier pin of the second row of carrier pins  114 , excepting the innermost carrier pin  114 - 1  and preferably the carrier pin  114 - 2  closer to the second pin  112 , via a bonding wire  119 . In addition, the first electrodes  101   a  and  101   b  at the front surfaces of the first die  101  and the second die  102  are electrically connected with the first pin  111  and the second pin  112  via a metal clip  251  having a wave shape as shown in  FIG. 11B , which includes a plurality of first parts  251   b ,  251   d  and  251   f  (bridge part) and a plurality of second parts  251   a ,  251   c ,  251   e  and  251   g  (valley part), where the plane of each first part is higher than that of each second part and the first part and the second part are alternatively formed in the metal clip  241  with both sides of each first part are connected with two second parts and vice versa. The second parts  251   a  and  251   g  at both ends of the metal clip  251  are coplanar and are mounted on the top surfaces of the bonding area  112   a  of the second pin  112  and the bonding area  111   a  of the first pin  111  respectively via a conductive adhesive. The second parts  251   c  and  251   e  are also coplanar and are mounted on the first electrode  102   a  of the second die  102  and the first electrode  101   a  of the first die  101  via an adhesive. The plane of the second parts  251   a  and  251   g  is lower than the plane of the second parts  251   c  and  251   e . The power control device further comprises a plastic package body  225  (not shown) encapsulating the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  251 , metal bumps  201 , the bonding wire  119  and the conductive structures  311  and  312 , where the bottom surfaces of lower pins, the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the bottom surface of the first pin  111  and the second pin  112 , and the bottom surfaces of the first bypass pin  121  and the second bypass pin  122  are exposed from the bottom surface of the plastic package body  225 , while the first die  101  and the second die  102 , the control die  103 , the metal clip  251 , the bonding wire  119  and the conductive structures  311  and  312  are completely encapsulated by the plastic package body  225 . 
       FIG. 8B  shows an alternative power device similar as that of  FIG. 8A  excepting that the lead frame does not include the first bypass pin  121  and the second bypass pin  122 , the connecting parts  115   c  and  115   d  and the conductive structures  311  and  312 . As such, the second electrode  101   b  at the front surface of the first die  101  is electrically connected with any carrier pin of the first row of carrier pins  113  via a bonding wire  119 , preferably with the innermost carrier pin  113 - 1  for a shortest bonding wire  119 . Similarly, the second electrode  102   b  at the front surface of the second die  102  is electrically connected with any carrier pin of the second row of carrier pins  114  and the first electrode  102   a  of the second die  102  is electrically with any carrier pins of the second row of carrier pins  114  that are not connected with the second electrode  102   b  via the bonding wire  119 , for example, the second electrode  102   b  is electrically connected with the innermost carrier pin  114 - 1  and the first electrode  112   a  is electrically connected with the carrier pin  114 - 2  closest to the carrier pin  114 - 1  carrier, thus the length of bonding wire  119  is optimized. The power control device further comprises a plastic package body  225  (not shown) covering the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  251 , the metal bumps  201 , and the bonding wires  119 , where the bottom surfaces of lower pins, the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the bottom surface of the first pin  111  and the second pin  112  are exposed from the bottom surface of the plastic package body  225 , while the first die  101  and the second die  102 , the control die  103 , the metal sheet  251 , the bonding wire  119  and the metal bumps  201  are completely encapsulated by the plastic package body  225 . 
     In another embodiment shown in  FIG. 8C , the structure of the power device is similar as that shown in  FIG. 8B  excepting that the control die  103  is mounted on the first row of carrier pins  113  and the second row of carrier pins  114  without flipping, where the back surface of the control die  103  is directly attached on the first row of carrier pins  113  and the second row of carrier pins  114  through a non-conductive adhesive. The second electrode  101   b  at the front surface of the first die  101  and the first electrode  102   a  and the second electrode  102   b  of the second die  102  are electrically connected with the corresponding electrode pads  103   a , without the metal bumps formed on top of the electrode pads, formed at the front surface of the control die  103  with bonding wires  119 . The other electrode pads  103   a  on the control die  103 , excepting the electrode pads connected to the second electrode  101   b  and  102   b  and the first electrode  102   a , positioned at two opposite edges of the control die  103  are electrically connected with the carrier pins of the first row of carrier pin  113  and the second row of carrier pin  114 . The electrode pads  103   a  for connecting with the second electrodes  101   b  and  102   b  and the first electrode  102   b  are positioned close to the die paddle  110 - 1  and  110 - 2  for shortest bonding wires  119 . The power control device further comprises a plastic package body  225  (not shown) that covers the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  251  and the bonding wire  119  with the bottom surfaces of lower pins, the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the bottom surface of the first pin  111  and the second pin  112  being exposed from the bottom surface of the plastic package body  225 , while the first die  101  and the second die  102 , the control die  103 , the metal clip  251  and the bonding wire  119  are completely encapsulated by the plastic package body  225 . 
     In the embodiments shown in  FIGS. 7B ,  8 A- 8 C, the first die  101  is an N-type channel MOSFET with top source and bottom drain, while the second die  102  is an N -type channel MOSFET with top drain and bottom source. The first electrode  101   a  of the first die  101  is the source electrode and the second electrode  101   b  is the gate electrode. The third electrode at the back surface of the first die is the drain electrode formed by a metal layer (not shown). The first electrode  102   a  of the second die  102  is the drain electrode and the second electrode  102   b  is the gate electrode. The third electrode at the back surface of the second die  102  is the source electrode formed by a metal layer. 
     The lead frame unit as shown in  FIG. 9A  is similar as that shown in  FIG. 7A , excepting that the second die paddle  110 - 2  includes a rectangular notch at the corner of the first transverse edge  110 - 2   a  and the second longitudinal edge  110 - 2   d  and an island pad  113   d  is formed in the notch. The lead frame unit further comprises a connecting structure  113   c  comprising a longitudinal section  113   c - 1  parallel to the second longitudinal edges  110 - 1   d  and  110 - 2   d  and a transverse section  113   c - 2  perpendicular to the longitudinal section  113   c - 1 , with the longitudinal section  113   c - 1  abutted on the upper part of any carrier pin of the first row of the carrier pins  113  and the second row of the carrier pins  114  excepting the innermost carrier pin  114 - 1  of the second row of carrier pins  114  that is connected to the second pin  112 . Preferably, one end of the longitudinal section  113   c - 1  is abutted with one end of the upper pin  113   a  of the innermost carrier pin  113 - 1  close to the second longitudinal edge  110 - 1   d  and both of the longitudinal section  113   c - 1  and the carrier pin  113 - 1  are coplanar. The transverse section  113   c - 2  of the connecting structure  113   c  and the horizontal plane of the island pad  113   d  forms an angle with one end of the transverse section  113   c - 2  connected with the longitudinal section  113   c - 1  and the other end connected with the island pad  113   d  as shown in  FIG. 9D  that is a cross section schematic diagram along the dotted line C 2 -C 2  in  FIG. 9A . Thus, the longitudinal section  113   c - 1  and the transverse section  113   c - 2  are not coplanar, where the transverse section  113   c - 2  is bent downward between the plane of the upper pin of the carrier pin and the plane of the island pad  113   b . In addition, the second pin  112  includes a connecting part  115   b , which is described above in  FIG. 7A , for connecting the second pin  112  with the innermost carrier pin  114 - 1  the second row of carrier pins  114 . Generally, the connecting part  115   b  is thinner than that the second pin  112  as shown in  FIG. 9E  that is the cross sectional schematic diagram along the dotted line C 3 -C 3  in  FIG. 9B . Alternatively, the connecting part  115   b  may have the same thickness as the second pin  112  and the carrier pin  114 - 1 . As shown in  FIG. 9B , the first die  101  is attached on the first die paddle  110 - 1 , so that the third electrode at the back surface thereof is directly attached on the top surface of the first die paddle  110 - 1 . The second die  102  is flipped and attached on the second die paddle  110 - 2  and the island pad  113   d , so that the first electrode  101   a  is attached on the top surface of the second die paddle  110 - 2  and the second electrode  102   b  is attached on the top surface of the island pad  113   d;  thus, the front surface of the first die  101  and the back surface of the second die  102  are coplanar with the top surfaces of the upper pins  113   a  and  114   a  of all carrier pins, such as the control die  103  is flipped and mounted on the first row of carrier pins  113  and the second row of carrier pins  114  and also partially overlapped on the first die  101  and the second die  102 . Metal bumps  201  are deposited on the electrode pads formed at the front surface of the control die  103  close to opposite edges and are aligned with and attached to the corresponding upper pins  113   a ,  114   a  of the first row of carrier pins  113  and the second row of carrier pins  114 . In the overlapping part of the control die  103  and the first die  101  and the second die  102 , the metal bumps  201  arranged on the plurality of pads arranged at the front surface at the overlapping part and positioned close to an edge of the control die  103  are respectively aligned with and attached on the first electrode  101   a  and the second electrode  101   b  of the first die  101  and the third electrode  102   c  at the back surface of the second die  102  as shown  FIG. 9C  that is the cross sectional schematic diagram along the line D 1 -D 2  in  FIG. 9B . 
     In  FIGS. 9F-9G , the first electrode  101   a  of the first die  101  and the third electrode  102   c  of the second die  102  are electrically connected with the second pin  112  with the metal clip  250  as described above. However, in this embodiment, the second part  250   a  is mounted on the top surface of the bonding area  112   a  of the second pin  112  through a conductive adhesive, while the second part  250   c  is mounted on the third electrode  102 C of the second die  102  through the an adhesive, which is different from the device structure of  FIGS. 7B-7C , and the second part  250   e  is mounted on the first electrode  101   a  of the first die  101  through an adhesive. The power control device further comprises a plastic package body  225  (not shown) that covers the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  250  and metal bumps  201 , with the bottom surfaces of the lower pins  113   b  and  114   b , the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the bottom surface of the first pin  111  and the second pin  112  and the bottom surface of the island pad  113   d  being exposed from the bottom surface of the plastic package body  225 . 
     The power device shown in  FIG. 10A  is similar as that shown in  FIG. 9A  excepting that the length of the first pin  111  extending along the first transverse edge  110 - 1   a  of the first die paddle  110 - 1  is smaller than that of the first transverse edge  110 - 1   a , and thus the first bypass pin  121  is formed adjacent to the first transverse edge  110 - 1   a  of the first die paddle  110 - 1  and positioned between the innermost carrier pin  113 - 1  of the first row of carrier pins  113  and the first pin  111 , which is similar as that shown in  FIG. 5A . The first bypass pin  121  includes a connecting part  115   c  for connecting the bypass pin  121  with the innermost carrier pin  113 - 1 . The second electrode  101   b  at the front surface of the first die  101  is electrically connected with the first bypass pin  121  through the conductive structure  311 . Each carrier pin of both the first row of carrier pins  113  and the second row of carrier pins  114  has strip shape. In addition, the island pad  113  is mechanically and electrically connected with any carrier pin of the first row of carrier pins  113  and the second row of carrier pins  114 , excepting the innermost carrier pins  113 - 1  and  114 - 1 , by a L-shaped connecting structure  117 ′ including a transverse section  117 ′ b  connecting to a longitudinal section  117 ′a. For example, in  FIG. 10A , one end of a transverse section  117 ′ b  is connected with the island  113   d  and one end of the longitudinal section  117 ′ a  is abutted with one end of the carrier pin  114 - 2 . Generally, the connecting structure  117 ′ is thinner than the island pad  113  and the carrier pins; thus, the connecting structure  117 ′ is covered by the plastic package body  225  after completing the plastic packaging process. Alternatively, the connecting structure  117 ′ may have the same thickness as the island pad  113  and the carrier pins; thus the bottom surface of the connecting structure  117 ′ is also exposed from the bottom surface of the plastic package body  225  (not shown). In addition, both the first electrode  101   a  of the first die  101  and the third electrode  102   c  of the second die  102  are electrically connected with the first pin  111  and the second pin  112  through the metal clip  251  as described above. In  FIG. 10A , the second part  251   a  is attached on the top surface of the bonding area  112   a  of the second pin  112  through a conductive adhesive, while the second part  251   c  is attached on the third electrode  102   c  of the second die  102  through an adhesive, the second part  250   e  is attached on the first electrode  101   a  of the first die  101  through an adhesive, and the second part  251   g  is attached on the top surface of the bonding area  111   a  of the first pin  111  through a conductive adhesive. The power control device further comprises a plastic package body  225  (not shown) that covers the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  251  and the conductive structure  311 , metal bumps  201 , the island pad  113   d  and the first bypass pin  121 , with the bottom surfaces of the carrier pins, the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the respective bottom surface of the first pin  111  and the second pin  112 , the bottom surface of the island pad  113   d  and the bottom surface of the first bypass pin  121  exposed from the bottom surface of the plastic package body  225 . 
       FIG. 10B  is a top view of an alternative power device that is similar to that of  FIG. 10A  excepting that the second electrode  101   b  at the front surface of the first die  101  is electrically connected with any carrier pin of the first row of carrier pins  113  via a bonding wire  119 , preferably the innermost carrier pin  113 - 1  for a shortest bonding wire  119 , as such the bypass pin  121  and the conductive structure  311  are omitted. As a result, the plastic package body  225  (not shown) also covers the bonding wire  119 . 
       FIG. 11A  is a top view of another alternative power device that is similar to that of  FIG. 10B  excepting that the control die  103  is mounted on the first row of carrier pins  113  and the second row of carrier pins  114  via a non-conductive adhesive without flipping, thus the connecting structure  117 ′ is omitted. The second electrode  101   b  of the first die  101  and the island pad  113   d  are electrically connected with the corresponding electrode pads  103   a  at the front surface of the control die  103  through the bonding wires  119 , preferably, the pads  103   a  positioned close to the first and second die paddles  110 - 1  and  110 - 2  for shortest bonding wires  119 . In addition, the other electrode pads  103   a , which are not connected with the second electrode  101   b  and the island pad  113   d , positioned close to two opposite edges of the control die  103  are electrically connected with the carrier pins of the first row of carrier pins  113  and the second row of carrier pins  114  through the bonding wires  119 . As shown in  FIG. 11B , which is a cross sectional schematic diagram of the device of  FIG. 11A  along the lined A 6 -A 6 , the second part  251  a is attached on the top surface of the bonding area  112   a  of the second pin  112  through a conductive adhesive, while the second part  251  c is attached on the third electrode  102   c  of the second die  102  through an adhesive (since the second die  102  is flipped), the second part  250   e  is attached on the first electrode  101   a  of the first die  101  through an adhesive, and the second part  251   g  is attached on the top surface of the bonding area  111   a  of the first pin  111  through a conductive adhesive. The power control device further comprises a plastic package body  225  (not shown) that covers the lead frame unit, the first die  101  and the second die  102 , the control die  103 , the metal clip  251  and bonding wires  119  with the bottom surfaces of the carrier pins, the bottom surfaces of the first die paddle  110 - 1  and the second die paddle  110 - 2 , the respective bottom surface of the first pin  111  and the second pin  112  and the bottom surface of the island pad  113   d  exposed from the bottom surface of the plastic package body  225 . 
     In the embodiments shown in  FIGS. 9B ,  10 A- 10 B and  11 A, the first die  101  is an N channel-type MOSFET and the second die  102  is an N channel-type MOSFET. The first electrode  101   a  of the first die  101  is the source electrode and the second electrode  101   b  is the gate electrode. The third electrode at the back surface of the first die is the drain electrode formed by a metal layer. Similarly, the first electrode  102   a  of the second die  102  is the source electrode and the second electrode  102   b  is the gate electrode. The third electrode at the back surface of the second die  102  is the drain electrode formed by a layer. 
     The above detailed descriptions are provided to illustrate specific embodiments of the present invention and are not intended to be limiting. Numerous modifications and variations within the scope of the present invention are possible. The present invention is defined by the appended claims.