Patent Publication Number: US-10770397-B2

Title: Semiconductor module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Japanese Patent Application No. 2018-134845, filed Jul. 18, 2018, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a semiconductor module including a vertical power semiconductor device. 
     In recent years, a surface mount integrated power module called POL (Power Over Lay) has been known. A semiconductor module of this type typically includes a dielectric film such as polyimide, a circuit part such as a power semiconductor device and a passive part mounted on one surface of the dielectric film, an electrode layer disposed on the other surface of the dielectric film, a sealing layer that covers the circuit part, and the like. 
     In accordance with the semiconductor module, the circuit part is electrically connected to the electrode layer via the dielectric film, and thus, it is possible to realize a power semiconductor module that achieves high integration of parts and shortening of the wiring length and that can be thinner and miniaturized while securing an insulation withstand voltage. Further, the design freedom of the electrode shape is high, and it is possible to form the electrode terminal in the power semiconductor device that controls passage of a large current into an arbitrary shape and size. 
     For example, Japanese Patent Application Laid-open No. 2015-170855 discloses a semiconductor device package in which a plurality of semiconductor devices are uniformly sealed with an embedding material between first and second dielectric layers each formed of a polyimide layer. In the first dielectric layer and the second dielectric layer, metal interconnects to be electrically connected to the front and rear surfaces of a semiconductor part are formed, thereby providing an electrical and thermal connection/path portion in the package structure. 
     SUMMARY 
     However, with the configuration disclosed in Japanese Patent Application Laid-open No. 2015-170855, in the case of arranging the plurality of semiconductor devices having different thicknesses on the first dielectric layer, it is necessary to match the thickness of each semiconductor device by using a spacer or the like because a gap is generated between a thinner semiconductor device and the second dielectric layer. Meanwhile, in the case of filling the gap with an embedding material and forming a via in the filled area, a problem of the increase in man-hours and complexity of processes occurs. 
     In view of the circumstances as described above, it is desirable to provide a semiconductor module capable of easily performing electrical connection of a semiconductor device having a thickness different from those of other parts to the front and rear surfaces. 
     In accordance with an embodiment of the present disclosure, there is provided a semiconductor module including: a base substrate; a first semiconductor part; and a second semiconductor part. 
     The base substrate includes a first dielectric film and an electrode layer, the first dielectric film having a mounting surface, the mounting surface including a first mounting area and a second mounting area. 
     The first semiconductor part is mounted on the first mounting area. 
     The second semiconductor part is mounted on the second mounting area. The second semiconductor part includes a vertical power semiconductor device, a conductive block, and a wiring substrate. The vertical power semiconductor device has a first surface and a second surface, the first surface including a first terminal to be connected to the electrode layer, the second surface including a second terminal. The conductive block is to be connected to the electrode layer. The wiring substrate electrically connects the conductive block and the second terminal. 
     In the semiconductor module, the second semiconductor part electrically connects the first and second terminal of the vertical power semiconductor device to the electrode layer via the conductive block and the wiring substrate. As a result, even in the case where the second semiconductor part has a thickness different from that of the first semiconductor part, it is possible to easily perform electrical connection to the first terminal and the second terminal. 
     The wiring substrate may include a second dielectric film and a wiring layer provided on the second dielectric film, the second dielectric film supporting the vertical power semiconductor device and the conductive block, the wiring layer connecting the conductive block and the second terminal. 
     The conductive block may include a plurality of conductive blocks that is supported by the second dielectric film and disposed around the vertical power semiconductor device. In this case, at least one of the plurality of conductive blocks may electrically connect the electrode layer and the second terminal. 
     The first dielectric film and the second dielectric film may each be a polyimide film. 
     The vertical power semiconductor device may further include a third terminal. The third terminal is connected to the electrode layer and controls electrical connection between the first terminal and the second terminal. 
     The second semiconductor part may be a package part that includes a package main body, the package main body sealing the vertical power semiconductor device, the conductive block, and the wiring substrate. 
     The semiconductor module may further include a sealing layer that seals at least one of the first mounting area and the second mounting area. 
     The semiconductor module may further include a partition wall member. The partition wall member is disposed on the mounting surface and divides the first mounting area and the second mounting area. 
     The sealing layer may include a first sealing portion and a second sealing portion, the first sealing portion sealing the first mounting area, the second sealing portion sealing the second mounting area. 
     The first dielectric film may further have an electrode forming surface opposed to the mounting surface. 
     The electrode layer is provided on the electrode forming surface and electrically connected to the first semiconductor part and the second semiconductor part via the first dielectric film. 
     As described above, in accordance with the present disclosure, it is possible to easily perform electrical connection of a semiconductor device having a thickness different from those of other parts to the front and rear surfaces. 
     These and other objects, features and advantages of the present disclosure will become more apparent in light of the following detailed description of best mode embodiments thereof, as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic cross-sectional view showing a configuration of a semiconductor module according to a first embodiment of the present disclosure; 
         FIG. 2  is a schematic plan view of the semiconductor module shown in  FIG. 1 ; 
         FIGS. 3A to 3G  are schematic diagrams showing a configuration example of an internal structure of a second semiconductor part in the semiconductor module; 
         FIG. 4  is a schematic cross-sectional view showing a configuration of a semiconductor module according to a comparative example; 
         FIG. 5  is a schematic cross-sectional view showing a configuration of a semiconductor module according to a second embodiment of the present disclosure; 
         FIG. 6  is a schematic cross-sectional view showing a configuration of a semiconductor module according to a third embodiment of the present disclosure; and 
         FIG. 7  is a schematic plan view of the semiconductor module shown in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 
     First Embodiment 
       FIG. 1  is a schematic cross-sectional view showing a configuration of a semiconductor module  100  according to a first embodiment of the present disclosure.  FIG. 2  is a schematic plan view of the semiconductor module  100  shown in  FIG. 1 . In each figure, the X axis, Y axis, and Z axis represent three axis directions orthogonal to each other, and the Z axis corresponds to the thickness (height) direction of the semiconductor module  100 . 
     The semiconductor module  100  according to this embodiment includes a first semiconductor part  10 , a second semiconductor part  20 , and a base substrate  30  that supports them. 
     The base substrate  30  includes a dielectric film  31  (first dielectric film). The dielectric film  31  is formed of an electrically insulating resin material having flexibility and a predetermined thickness. In this embodiment, the dielectric film  31  includes a polyimide film having a thickness of 25 μm. Polyimide is very advantageous from the viewpoints of processability, insulation withstand voltage characteristics, chemical resistance, and the like. 
     The present disclosure is not limited thereto, and the thickness of the dielectric film  31  can be appropriately set in accordance with the dielectric constant of the material, the necessary magnitude of the insulation withstand voltage, or the like. For example, the thickness of the dielectric film  10  is appropriately selected within the range of not more than 20 μm and not less than 50 μm. The dielectric material is also not limited to polyimide. For example, an appropriate material such as polytetrafluoroethylene (PTFE), polysulfone, and a liquid crystal polymer can be adopted. 
     Also the shape of the dielectric film  31  is not particularly limited. The dielectric film  31  is typically formed in a rectangular shape (see  FIG. 2 ). The size of the dielectric film  31  on the plane is not particularly limited as long as the first semiconductor part  10  and the second semiconductor part  20  can be mounted thereon. For example, the dielectric film  31  has lengths of sides parallel to the X-axis direction and the Y-axis direction of not less than 10 mm and not more than 500 mm. 
     The dielectric film  31  has a mounting surface  31   a  and an electrode forming surface  31   b  opposite to the mounting surface  31   a . The first semiconductor part  10  and the second semiconductor part  20  are to be mounted on the mounting surface  31   a . The mounting surface  31   a  includes a first mounting area a 1  and a second mounting area a 2 . The first semiconductor part  10  is to be mounted on the first mounting area a 1 . The second semiconductor part  20  is to be mounted on the second mounting area a 2 . The part to be mounted on the mounting surface  31   a  is not limited to the first semiconductor part  10  and the second semiconductor part  20 , and may include a control IC that drives them, a passive part such as a capacitor, and the like. Hereinafter, the part to be mounted on the mounting surface  31   a  will be referred to also as “circuit part”. 
     A plurality of circuit parts including the first semiconductor part  10  and the second semiconductor part  20  is mounted on the mounting surface  31   a  via the adhesive layer  33 , and an electrode layer  32  to be electrically connected to the above-mentioned circuit part is disposed on the electrode forming surface  31   b  via the dielectric film  31 . 
     The adhesive layer  33  includes a liquid adhesive, a fluid adhesive, or a film-like adhesive sheet applied to the mounting surface  31   a . The type of the adhesive layer  33  is not particularly limited. The adhesive layer  33  is formed of an appropriate insulating resin material such as an epoxy resin material and an acrylic resin material. The thickness of the adhesive layer  33  is not particularly limited, and is, for example, 15 μm. Further, it is favorable that the adhesive layer  33  has high heat resistance in consideration of temperature rise during driving. Note that the adhesive layer  33  may be provided on the entire surface of the mounting surface  31   a  or may be selectively provided in the mounting area of the circuit part. 
     The electrode layer  32  is disposed on the electrode forming surface  31   b  in the dielectric film  31 , and typically includes a metal plating layer containing copper (Cu) or the like as a main component. The electrode layer  32  includes a via V as an interlayer connection portion to be electrically connected to the above-mentioned circuit part via the dielectric film  31 . 
     When forming the electrode layer  32 , first, laser light is applied from the side of the electrode forming surface  31   b  to the electrode terminal of each circuit part (the first semiconductor part  10  and the second semiconductor part  20 ) mounted on the mounting surface  31   a  of the dielectric film  31 . As a result, the dielectric film  31  and the adhesive layer  33  are drilled, and each electrode terminal is exposed to the side of the electrode forming surface  31   b . Subsequently, a conductor layer to be a seed layer is formed on the electrode forming surface  31   b  by a sputtering method, and then, a cupper plating layer having a predetermined thickness is formed by an electrolytic plating method. As a result, the electrode layer  32  including the via V to be connected to the circuit part is formed. 
     For the formation of the conductor layer to be a seed layer, the sputtering method does not necessarily need to be adopted, and an electroless plating method may be adopted. The thickness (thickness from the electrode forming surface  31   b ) of the electrode layer  32  is not particularly limited, and is, for example, not less than approximately 50 μm and not more than 100 μm. As a result, the current characteristics of the electrode layer  32  and productivity can be secured. Further, the thicker the electrode layer  32  the larger the current that can be handled and the better the heat dissipation. Therefore, it is possible to cause the electrode layer  32  to function as the heat sink for the heat generated from the circuit part and as the heat radiation electrode. 
     Note that in the case where the electrode layer  32  is formed of Cu plating, it is favorable to provide at least one anti-oxidation film on the surface. Examples of the material of the film include Ni, Ni/Au, and Ni/Pd/Au. The electrode layer  32  functions as an eternal terminal to be mounted on a motherboard  50  via a bonding material such as solder. 
     As the plating method to be used for forming the electrode layer  32 , a subtractive method of forming a plating layer on the entire dielectric film  31  and then removing a part thereof other than necessary portions, and an additive method (sub-additive method) of selectively plating only necessary portions via a plating resist formed on the dielectric film  31  can be adopted. The former is used here, and the electrode layer  32  is patterned into a plurality of electrode portions  32 E having a predetermined shape by using a photolithographic technology. 
     The first semiconductor part  10  is mounted on the first mounting area a 1  of the mounting surface  31   a , and held by the adhesive layer  33 . The first semiconductor part  10  typically includes an IC part. The first semiconductor part  10  may be a bare chip part or a package part. On the active surface (surface facing the mounting surface  31   a ) of the first semiconductor part  10 , a plurality of electrode pads P to be connected to the via V of the electrode layer  32  is arranged. 
     On the non-active surface (surface opposed to the active surface) of the first semiconductor part  10 , a heat sink for heat radiation may be bonded via a bonding material such as solder. This heat sink mainly contains a conductive material such as Cu and Al as a main component, and may be a metal plate or a thick metal/alloy film formed by plating or sputtering. Further, for heat radiation, a substrate referred to as DBC (DBA) in which Cu is bonded to a ceramic substrate may be bonded to the above-mentioned non-active surface. 
     The second semiconductor part  20  is mounted on the second mounting area a 2  of the mounting surface  31   a , and held by the adhesive layer  33 . The second semiconductor part  20  includes a vertical power semiconductor device  21 , a conductive block  22 , and a wiring substrate  23 . 
     The vertical power semiconductor device  21  (hereinafter, also referred to simply as “a semiconductor device”) is a power transistor for large current, which flows current in the thickness direction of the device. However, the vertical power semiconductor device  21  is not limited to thereto, and may be another power semiconductor device such as a power diode. Examples of the power transistor include a bipolar transistor, MOSFET, and IGBT formed of Si, SiC, GaN, or the like. The second semiconductor part  20  may be a bare chip part or a package part. 
     The semiconductor device  21  has a first surface  21   a  and a second surface  21   b  opposed to the first surface  21   a . The first surface  21   a  faces the mounting surface  31   a . The first surface  21   a  includes a the first terminal S to be connected to the electrode layer  32 , and the second surface  21   b  includes a second terminal D that is electrically connectable to the first terminal S. The first surface  21   a  further includes a third terminal G that controls electrical connection between the first terminal S and the second terminal D. 
     Note that the first terminal S and the second terminal D are each a conduction terminal through which large current flows out or flows in, and respectively correspond to a source terminal and a drain terminal. The second terminal D includes a plurality of second terminals D, and the second terminals D are arranged on the second surface  21   b  of the semiconductor device  21 . The third terminal G corresponds to a gate terminal as a control terminal, and is electrically connected to an electrode portion for a gate terminal in the electrode layer  32 . The second terminal D is electrically connected to a part of the plurality of electrode pads P of the first semiconductor part  10  via the wiring substrate  23 , the conductive block  22 , and the electrode layer  32 . 
     The conductive block  22  typically includes a metal block formed of a good electrical conductor such as Cu. 
     The conductive block  22  is disposed around the semiconductor device  21 . On end of the conductive block  22  is connected to a predetermined via V of the mounting surface  31   a , and the other end thereof is connected to a wiring layer  23   w  of the wiring substrate  23 . The conductive block  22  is formed to have a thickness that is the same or substantially the same as that of the semiconductor device  21 . As a result, it is possible to perform electrical connection between the conductive block  22  and the semiconductor device  21  without largely deforming the wiring substrate  23 . 
     The surface of the conductive block  22  is coated with a metal film (plating) formed of Sn, Ni, Ag, or the like. The film is formed on the entire surface of the conductive block  22 . However, the present disclosure is not limited thereto, and the film may be formed on only two surfaces connected to the via V of the mounting surface  31   a  and the wiring layer  23   w  of the wiring substrate  23 . In this case, the conductive block  22  having the film can be prepared by dicing a Cu plate having the film on both surfaces is formed. 
     The wiring substrate  23  has a stacked structure of a dielectric film  23   f  (second dielectric film) and the wiring layer  23   w.    
     The dielectric film  23   f  is formed of an electrically insulating resin material having flexibility and a predetermined thickness, similarly to the dielectric film  31  constituting the base substrate  30 . In this embodiment, the dielectric film  23   f  is formed of a polyimide film having a thickness of 25 μm. Polyimide is very advantageous from the viewpoints of processability, insulation withstand voltage characteristics, chemical resistance, and the like. 
     The present disclosure is not limited thereto, and the thickness of the dielectric film  23   f  can be appropriately set in accordance with the dielectric constant of the material, the necessary magnitude of the insulation withstand voltage, or the like. For example, the thickness of the dielectric film  23   f  is appropriately selected within the range of not more than 20 μm and not less than 50 μm. The dielectric material is also not limited to polyimide. For example, an appropriate material such as polytetrafluoroethylene (PTFE), polysulfone, and a liquid crystal polymer can be adopted. 
     Also the shape of the dielectric film  23   f  is not particularly limited. The dielectric film  23   f  is typically formed in a rectangular shape. The size of the dielectric film  23   f  on the plane is not particularly limited as long as favorable electrical connection between the second surface  21   b  of the semiconductor device  21  and the conductive block  22  can be secured. For example, the dielectric film  23   f  may be a strip-like film that partially connects the second terminal D and the conductive block  22 , or a wide film that comprehensively connects the entire area of the second surface  21   b  and the conductive block  22 . 
     The dielectric film  23   f  holds the semiconductor device  21  via an adhesive layer  25 . The adhesive layer  25  includes a liquid adhesive, a fluid adhesive, or a film-like adhesive sheet applied to the dielectric film  23   f  The type of the adhesive layer  25  is not particularly limited. The adhesive layer  25  is formed of an appropriate insulating resin material such as an epoxy resin material and an acrylic resin material. The thickness of the adhesive layer  25  is not particularly limited, and is, for example, 15 μm. Further, it is favorable that the adhesive layer  25  has high heat resistance in consideration of temperature rise during driving. Note that the adhesive layer  25  may be provided on the entire surface of the dielectric film  23   f  or may be selectively provided in the mounting area of the semiconductor device  21 . 
     The wiring layer  23   w  is provided on the dielectric film  23   f , and electrically connects the conductive block  22  and the second terminal D of the semiconductor device  21 . In this embodiment, the wiring layer  23   w  includes a plurality of vias w 1  and a metal layer w 2 . The plurality of vias w 1  is connected to the semiconductor device  21  and the conductive block  22 , and penetrates the dielectric film  23   f . The metal layer w 2  is provided on the main surface of the dielectric film  23   f , which is opposed to the side of the adhesive layer  25 , and connects the plurality of vias w 1  to each other. 
     The wiring layer  23   w  can be formed by a method similar to the method of forming the electrode layer  32 . Laser light is applied from the surface of the dielectric film  23   f , which is opposed to the side of the adhesive layer  25 , to the second terminal D of the semiconductor device  21  mounted on the adhesive layer  25  of the dielectric film  23   f . As a result, the dielectric film  23   f  and the adhesive layer  25  are drilled, and the second terminal D is exposed. Subsequently, a conductor layer to be a seed layer is formed on the above-mentioned opposed surface of the dielectric film  23   f  by a sputtering method, and then, a cupper plating layer having a predetermined thickness is formed by an electrolytic plating method. As a result, the metal layer w 2  including the vias w 1  to be connected to the semiconductor device  21  is formed. The thickness of the metal layer w 2  is not particularly limited. As the thickness is larger, the function as a heat sink for improving the heat radiation effect of the semiconductor device  21  can be improved. 
     By forming the wiring layer  23   w  including the vias w 1  and the metal layer w 2  on the dielectric film  23   f , the second terminal D of the semiconductor device  21  can be electrically connected to the electrode layer  32  via the wiring layer  23   w  and the conductive block  22 . Further, since the semiconductor device  21  is sandwiched between the electrode layer  32  on the side of the base substrate  30  and the metal layer w 2  on the side of the wiring substrate  23 , it is possible to dramatically improve the heat dissipation of the semiconductor device  21  and stably drive the semiconductor device  21  by forming the electrode layer  32  and the metal layer w 2  to have a relatively large thickness. 
     The conductive block  22  is supported by the wiring substrate  23 . The number of the conductive blocks  22  may be one or two or more. Also the shape of the conductive block  22  is not particularly limited. The conductive block  22  may be a columnar block body such as a prismatic block body and a cylindrical block body, or may be a longitudinal, L-shaped, or annular block body continuous in at least one axis direction. 
       FIGS. 3A to 3G  are schematic plan views showing some examples of the form of the conductive block  22  on the mounting surface. 
       FIG. 3A  shows an example in which a conductive block  22  which is longitudinal is disposed along one side of the semiconductor device  21 .  FIG. 3B  and  FIG. 3C  respectively show an example in which one conductive block  22  which is columnar is disposed along one side of the semiconductor device  21  and an example in which two conductive blocks  22  which are columnar are disposed along one side of the semiconductor device  21 .  FIG. 3D  and  FIG. 3E  respectively show an example in which a conductive block  22  which is L-shaped is disposed along two adjacent sides of the semiconductor device  21  and an example in which a plurality of conductive blocks  22  which are L-shaped are disposed along two adjacent sides of the semiconductor device  21 .  FIG. 3F  and  FIG. 3G  respectively show an example in which a conductive block  22  which is rectangular and annular is disposed around the semiconductor device  21  and an example in which a plurality of conductive blocks  22  which are columnar are disposed around the semiconductor device  21 . Note that in each figure, a reference symbol  24  indicates a package main body (described below). 
     Since the conductive block  22  includes a metal block formed of Cu or the like, the conductive block  22  has a function as a heat sink that absorbs heat from the semiconductor device  21  in addition to the function as an electrode. In this case, although  FIGS. 3C, 3E, and 3G  each show an example in which the plurality of conductive block  22  are disposed, the wiring layer  23   w  may be formed so that at least one of the plurality of conductive blocks  22  electrically connects the electrode layer  32  and the second terminal D. In this case, the conductive block  22  that is not connected to the second terminal D functions as a dummy terminal. 
     The second semiconductor part  20  may further include a package main body  24 . As a result, the handleability of the second semiconductor part  20  is improved, and the mountability to the base substrate  30  and the sealability of the semiconductor device  21  can be enhanced. In this case, from the viewpoint of the heat dissipation, the package main body  24  may be formed such that the metal layer w 2  or the conductive block  22  is exposed to the outside. 
     The second semiconductor part  20  is formed to have a thickness larger than that of the first semiconductor part  10  as shown in  FIG. 1 . However, the present disclosure is not limited thereto, and the second semiconductor part  20  may have a thickness smaller than that of the first semiconductor part  10  or a thickness that is the same as that of the first semiconductor part  10 . Further, also the planar shape and size of the second semiconductor part  20  are not particularly limited. As shown in  FIG. 2 , the second semiconductor part  20  may be formed to have the same shape and size as those of the first semiconductor part  10  or a shape different from that of the first semiconductor part  10  and a size larger or smaller than that of the first semiconductor part  10 . 
     The semiconductor module  100  further includes a sealing layer  40  that seals at least one of the first mounting area a 1  and the second mounting area a 2 . In this embodiment, the sealing layer  40  is provided on the entire area of the mounting surface  31   a , which includes the first mounting area a 1  and the second mounting area a 2 . 
     The sealing layer  40  is typically formed of an epoxy synthetic resin material, and inhibits outside air containing water and the like from coming into contact with the first semiconductor part  10  and the second semiconductor part  20 . In this embodiment, the thickness of the sealing layer  40  is larger than the thickness of the first semiconductor part  10 , and the same as or smaller than the thickness of the second semiconductor part  20 . As a result, the sealing layer  40  is formed in the form of overmolding for the first semiconductor part  10 , and exposes the metal layer w 2  for the second semiconductor part  20 , which makes it possible to enhance the heat dissipation of the semiconductor device  21 . 
     The present disclosure is not limited thereto, and the sealing layer  40  may be formed to have such a thickness that the upper surface of the first semiconductor part  10  is exposed (expose molding). In this case, by using the upper surface of the exposed first semiconductor part  10  as a bonding area or the like of the heat sink, the heat dissipation of the first semiconductor part  10  can be enhanced. Further, the present disclosure is not limited to the above-mentioned example, and the sealing layer  40  may be formed to have a thickness capable of covering both the first semiconductor part  10  and the second semiconductor part  20 . 
     In the semiconductor module  100  according to this embodiment configured as described above, the second semiconductor part  20  electrically connects the first and second terminals S and D to the electrode layer  32  via the conductive block  22  and the wiring substrate  23 . As a result, also in the case where the second semiconductor part  20  has a thickness different from that of the first semiconductor part  10 , it is possible to easily perform electrical connection to the first terminal S and the second terminal D. 
     For example, as schematically shown  FIG. 4 , in a semiconductor module  1  in which two semiconductor devices SD 1  and SD 2  are sandwiched by a first dielectric film F 1  and a second dielectric film F 2 , in the case where the semiconductor device SD 2  is a vertical power semiconductor device, a wiring layer EL 2  for drawing out via the via V 1  to the terminal portion of the upper surface of the semiconductor device SD 2  and an interlayer via V 2  for connecting the wiring layer EL 2  to an electrode layer EL 1  on the first dielectric film F 1  are provided on the second dielectric film F 2 . At this time, if the semiconductor device SD 2  is thinner than the semiconductor device SD 1 , it is necessary to provide a spacer (shim SH) between the terminal portion of the upper surface of the semiconductor device SD 2  and the second dielectric film F 2  to match the thickness with the thickness of the semiconductor device SD 1  because a gap is generated between the semiconductor device SD 2  and the second dielectric film F 2 . Therefore, in the semiconductor module  1  having such a structure, in the case where the thicknesses of the semiconductor devices SD 1  and SD 2  differ, a problem of the increase in the number of wiring-forming steps of forming wiring for the electrode layer EL 1  and complexity of processes occurs. 
     Meanwhile, in the semiconductor module  100  according to this embodiment, the second semiconductor part  20  includes the conductive block  22  and the wiring substrate  23  for electrically connecting the second terminal D of the vertical power semiconductor device  21  to the mounting surface  31   a  of the base substrate  30 , which makes it easy to perform electrical connection of each terminal of the second semiconductor part  20  even in the case where the thickness of the second semiconductor part  20  is different from that of the first semiconductor part  10 . 
     Further, by preparing the second semiconductor part  20  having the above-mentioned configuration in advance, it only needs to mount the second semiconductor part  20  and the first semiconductor part  10  on the base substrate  30  to produce the semiconductor module  100 . Therefore, it is possible to simplify the configuration of the entire module, drastically reduce the number of production steps, and improve the yield because it is unnecessary to perform the process of forming wiring after mounting. 
     Further, in accordance with this embodiment, since the second semiconductor part  20  includes the wiring substrate  23  including the metal layer w 2 , the heat generating semiconductor device  21  mounted on the base substrate  30  can be sandwiched between the electrode layer  32  and the metal layer w 2 , and it is possible to improve the heat dissipation of the semiconductor device  21 , enhance the deformation resistance of the semiconductor device  21  against the external stress or thermal stress, and secure stable driving of the semiconductor device  21 . 
     Second Embodiment 
       FIG. 5  is a schematic cross-sectional view showing a configuration of a semiconductor module  200  according to a second embodiment of the present disclosure. Hereinafter, the configuration different from that in the first embodiment will be mainly described, and the same configuration as that of the first embodiment will be denoted by the same reference symbol, and description thereof will be omitted or simplified. 
     The semiconductor module  200  according to this embodiment is different from the semiconductor module  100  according to the first embodiment in the configuration of a second semiconductor part  220 . Specifically, in the second semiconductor part  220  according to this embodiment, the wiring layer  23   w  includes the metal layer w 2  disposed between the dielectric film  23   f  and the semiconductor device  21 , thereby connecting the wiring layer  23   w  directly to the second terminal D (drain terminal) of the semiconductor device  21  without vias. As a result, the metal layer w 2  can be brought closer to the semiconductor device  21 , and thus, it is possible to enhance the heat dissipation of the semiconductor device  21 . 
     Third Embodiment 
       FIG. 6  is a schematic cross-sectional view showing a configuration of a semiconductor module  300  according to a third embodiment of the present disclosure.  FIG. 7  is a schematic plan view of the semiconductor module shown in  FIG. 6 . Hereinafter, the configuration different from that in the first embodiment will be mainly described, and the same configuration as that of the first embodiment will be denoted by the same reference symbol, and description thereof will be omitted or simplified. 
     The semiconductor module  300  according to this embodiment includes the first semiconductor part  10 , the second semiconductor part  20 , and the base substrate  30  similarly to the semiconductor module  100  according to the first embodiment. The third embodiment is different from the first embodiment in that the semiconductor module  300  includes a partition wall member  60 . 
     The partition wall member  60  is disposed on the mounting surface  31   a  of the base substrate  30 , and divides the first mounting area a 1  and the second mounting area a 2 . As shown in  FIG. 7 , the partition wall member  60  includes a rectangular frame including a first opening  60   a  and a second opening  60   b . The first opening  60   a  houses the first semiconductor part  10 . The second opening  60   b  houses the second semiconductor part  20 . The partition wall member  60  is supported by the mounting surface  31   a  via the adhesive layer  33 . A sealing portion may be selectively provided in any one of the first and second openings  60   a  and  60   b , or a first sealing portion  41  and a second sealing portion  42  may respectively be provided in the first opening  60   a  and the second opening  60   b . Alternatively, the first and second openings  60  and  60   b  do not necessarily need to be filled with a sealing portion, and may form a space. 
     For example, in a power semiconductor device formed of a semiconductor material such as Si, GaN, SiC, Ga 2 O 3 , and diamond, the device characteristics deteriorate due to the cure shrinkage stress of a resin forming the sealing layer, and it is difficult to secure desired module characteristics in some cases. Meanwhile, if the sealing layer is omitted or the sealing layer is formed of a soft resin material, it is difficult to suppress a warp of the base substrate  30 . 
     In this regard, in this embodiment, by mounting the frame-shaped partition wall member  60  on the mounting surface  31   a , the rigidity of the partition wall member  60  is used to suppress a warp and deformation of the base substrate  30 . As a result, even in the case of providing no sealing portion, it is possible to effectively suppress a warp and deformation of the base substrate  30  by the partition wall member  60 . 
     The material forming the partition wall member  60  is not particularly limited as long as it has such a rigidity that a warp of the first mounting area a 1  can be suppressed. The material forming the partition wall member  60  may be a conductor or a non-conductor. The conductor is typically formed of a metal material. As a result, a heat radiation path of the circuit part (particularly, the power second semiconductor part  20  in this embodiment) can be formed. The metal material is not particularly limited, and a material such as copper (Cu) having a high thermal conductivity and a small thermal expansion coefficient is favorable. As the partition wall member  60 , a metal having a high hardness or high melting point such as tungsten (W) and molybdenum (Mo) or an alloy material such as Cu—W and Cu—Mo may be adopted. As a result, it is possible to easily secure desired rigidity. Meanwhile, ceramic materials such as alumina, silica, and boron nitride are favorable as the non-conductor. 
     The shape of the partition wall member  60  is not limited to the rectangle shape, and may be a circular or elliptical frame shape. Further, the shape of the partition wall member  60  is not limited to the frame shape. An appropriate shape such as a linear shape, an L-shape, and a cross shape can be adopted. By forming the partition wall member  60  so that it is exposed from the side surface of the module, it is possible to form a semiconductor module having excellent heat dissipation. 
     For the first sealing portion  41 , a general-purpose epoxy synthetic resin material can be used. Meanwhile, for the second sealing portion  42 , an epoxy synthetic resin material that is softer (having a lower elastic modulus) than the first sealing portion  41 , e.g., a silicone resin or an epoxy resin having a low stress may be used. As a result, it is possible to inhibit the semiconductor device  21  that is a power semiconductor device from deteriorating due to the cure shrinkage stress of a resin. A gel-like material having the Young&#39;s modulus of not more than 0.01 MPa at room temperature or a material having a Tg close to room temperature can be used as the resin material forming the second sealing portion  42 . 
     As described above, also in the semiconductor module  300  according to this embodiment, effect similar to those in the first embodiment can be achieved. In accordance with this embodiment, it is possible to suppress degradation of the device characteristics of the semiconductor parts  10  and  20  due to the stress of a sealing resin while suppressing a warp of the base substrate  30 . 
     Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-mentioned embodiments, and various modifications can be made. 
     For example, although in the above-mentioned embodiments, the semiconductor modules  100  and  200  in which the first and second semiconductor parts  10  and  20  are mounted on the base substrate  30  have been described as examples, parts to be mounted are not limited thereto, and an IC part and a passive part such as a capacitor for control may be mounted together. 
     Further, although the partition wall member  60  has included a common frame member surrounding the first and second mounting areas in the above-mentioned third embodiment, separate frame members may be used. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.