Semiconductor device

Abstract

To provide a semiconductor device in which dimensional defects such as misalignment of semiconductor elements are restrained.SOLUTION: A semiconductor device has a semiconductor element 40 including a first semiconductor element 40H and a second semiconductor element 40L, upper conductors 50H, 50L, lower conductors 60H, 60L, solder 100, a first covering member 110, and a second covering member 120. The solder has upper solders 102H, 102L and lower solders 103H, 103L. The first covering member covers the upper conductor and the lower conductor. The second covering member covers a part of the first covering member, and the upper solder is less likely to wet and spread than the first covering member. The second covering member is placed on the upper solder desired range surfaces 52H, 52L where the upper conductor is desired to be connected to the semiconductor element by the upper solder.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The disclosure provided herein relates to semiconductor devices. [Background technology]

[0002] Patent Document 1 describes a semiconductor device including a semiconductor element constituting an upper arm of an upper and lower arm circuit and a semiconductor element constituting a lower arm. One of the heat sinks is disposed on the back side of the semiconductor element in the Z direction and is electrically connected to the collector electrode via solder. Another of the heat sinks is disposed on the front side of the semiconductor element in the Z direction and is electrically connected to the emitter electrode via solder. It is described that the front side heat sink and the back side heat sink may be provided with a plating film of Ni, Au, or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7111140 Summary of the Invention [Problem to be solved by the invention]

[0004] If the entire backside heat sink is plated with a gold or other plating film, the solder applied between the backside heat sink and the semiconductor element during manufacturing tends to wet and spread over the entire backside heat sink, which can cause dimensional defects such as misalignment of the semiconductor element due to the solder overflowing from the desired connection area.

[0005] Therefore, an object of the present disclosure is to provide a semiconductor device in which dimensional defects such as misalignment of semiconductor elements are suppressed. [Means for solving the problem]

[0006] A semiconductor device according to an aspect of the present disclosure includes: A semiconductor element (40) having an upper electrode (42) and a lower electrode (43), the semiconductor element (40) including a first semiconductor element (40H) and a second semiconductor element (40L) arranged in a lateral direction (X) that is a direction perpendicular to an overlapping direction (Z) in which the upper electrode and the lower electrode overlap; an upper conductor (50H, 50L) having a first upper conductor (50H) overlapping an upper electrode of a first semiconductor element and a second upper conductor (50L) overlapping an upper electrode of a second semiconductor element; a bottom conductor (60H, 60L) having a first bottom conductor (60H) overlapping a bottom electrode of a first semiconductor element and a second bottom conductor (60L) overlapping a bottom electrode of a second semiconductor element; A solder (100) having upper solders (102H, 102L) for connecting an upper electrode of a semiconductor element to an upper conductor, and lower solders (103H, 103L) for connecting a lower electrode of the semiconductor element to a lower conductor; a first covering member (110) that covers the upper conductor and the lower conductor; a second covering member (120) that covers a portion of the first covering member and through which the solder is less likely to spread than the first covering member; A second covering member is placed on the upper solder desired area surfaces (52H, 52L) where connection to the semiconductor element by the upper solder is desired in the upper conductor.

[0007] When the upper conductor (50H, 50L) is joined to the semiconductor element (40) via the upper solder (102H, 102L), the upper solder is contained within the desired area because the second covering member (120) is provided on the desired area of ​​the upper solder (52H, 52L). This suppresses dimensional defects such as misalignment of the semiconductor element.

[0008] It should be noted that the reference numbers in parentheses above merely indicate the corresponding relationship with the configurations described in the embodiments described below, and do not in any way limit the technical scope. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a schematic configuration of a drive system of a vehicle to which a semiconductor device is applied; [Diagram 2] FIG. 1 is a plan view showing a semiconductor device. [Diagram 3] 3 is a plan view of the semiconductor device shown in FIG. 2 with a sealing body removed. [Figure 4] 4 is a plan view of the semiconductor device shown in FIG. 3 with a part of the heat sink removed. [Diagram 5] FIG. 4 is a plan view illustrating a heat sink and a main terminal. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI shown in FIG. 2. [Figure 7] 7 is a cross-sectional view taken along the line VII-VII shown in FIG. 2. [Figure 8] 13 is an enlarged view of a heat sink connected to an emitter electrode of a second semiconductor element. FIG. [Figure 9] 4 is an enlarged view of a heat sink connected to an emitter electrode of a first semiconductor element. FIG. [Figure 10] FIG. 10 is an enlarged view of a joint portion connected to the heat sink in FIG. [Figure 11] FIG. 11 is an enlarged view of a joint portion connected to the heat sink in FIG. [Figure 12] 1 is a flowchart illustrating a manufacturing method. [Figure 13] 10 is a cross-sectional view illustrating a stacking process in the manufacturing process. [Figure 14] FIG. 4 is a cross-sectional view illustrating a layering step in the manufacturing process. [Figure 15] FIG. 11 is a plan view showing a semiconductor device according to a second embodiment. [Figure 16] FIG. 4 is a cross-sectional view showing a semiconductor device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, the other embodiment described previously may be applied to the other parts of the configuration.

[0011] In addition to combinations of parts that are explicitly stated as possible in each embodiment, it is also possible to partially combine embodiments together, embodiments and variations, and variations together, even if not explicitly stated, provided that there are no particular problems with the combination.

[0012] The semiconductor device 20 of this embodiment is applied to, for example, a power conversion device 4 of a moving body using a rotating electric machine as a drive source. The moving body is, for example, an electric vehicle such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), an aircraft such as an electric vertical take-off and landing aircraft or a drone, a ship, a construction machine, or an agricultural machine. An example of application to a vehicle will be described below.

[0013] (First embodiment) First, a schematic configuration of a vehicle drive system 1 will be described with reference to FIG.

[0014] <Vehicle drive system> As shown in FIG. 1, a vehicle drive system 1 includes a DC power supply 2, a motor generator 3, and a power conversion device 4.

[0015] The DC power supply 2 is a DC voltage source composed of a chargeable and dischargeable secondary battery. The secondary battery is, for example, a lithium-ion battery or a nickel-metal hydride battery. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a drive source for the vehicle, that is, an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion device 4 performs power conversion between the DC power supply 2 and the motor generator 3.

[0016] <Power conversion device> Next, the circuit configuration of the power conversion device 4 will be described with reference to Fig. 1. The power conversion device 4 includes a power conversion circuit. As shown in Fig. 1, the power conversion device 4 includes a smoothing capacitor 5 and an inverter 6 which is a power conversion circuit.

[0017] The smoothing capacitor 5 mainly smoothes the DC voltage supplied from the DC power supply 2. The DC power supply 2 corresponds to a battery. The smoothing capacitor 5 is connected to a P line 7, which is a power line on the high potential side, and an N line 8, which is a power line on the low potential side. The P line 7 is connected to the positive electrode of the DC power supply 2, and the N line 8 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 5 is connected to the P line 7 between the DC power supply 2 and the inverter 6. Similarly, the negative electrode is connected to the N line 8 between the DC power supply 2 and the inverter 6. The smoothing capacitor 5 is connected in parallel to the DC power supply 2. The smoothing capacitor 5 may be referred to as an electric component.

[0018] The inverter 6 is a DC-AC conversion circuit. The inverter 6 converts a DC voltage into a three-phase AC voltage in accordance with switching control by a control circuit (not shown) and outputs the voltage to the motor generator 3. This drives the motor generator 3 to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 6 converts the three-phase AC voltage generated by the motor generator 3 upon receiving rotational force from the wheels into a DC voltage in accordance with switching control by the control circuit and outputs the DC voltage to the P line 7. In this way, the inverter 6 performs bidirectional power conversion between the DC power source 2 and the motor generator 3.

[0019] The inverter 6 is configured with upper and lower arm circuits 9 for three phases. The upper and lower arm circuits 9 are sometimes referred to as legs. The upper and lower arm circuits 9 each have an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the P line 7 and the N line 8, with the upper arm 9H on the P line 7 side. A connection point between the upper arm 9H and the lower arm 9L is connected to the winding 3a of the corresponding phase in the motor generator 3 via an output line 10. The inverter 6 has six arms. At least a portion of each of the P line 7, the N line 8, and the output line 10 is formed of a conductive member such as a bus bar.

[0020] The elements constituting each arm include an IGBT 11 which is a switching element, and a freewheeling diode 12. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In this embodiment, an n-channel IGBT 11 is adopted. The diode 12 is connected inversely parallel to the corresponding IGBT 11. In the upper arm 9H, the collector of the IGBT 11 is connected to the P line 7. In the lower arm 9L, the emitter of the IGBT 11 is connected to the N line 8. The emitter of the IGBT 11 in the upper arm 9H and the collector of the IGBT 11 in the lower arm 9L are connected to each other. The anode of the diode 12 is connected to the emitter of the corresponding IGBT 11, and the cathode is connected to the collector.

[0021] The power conversion device 4 may further include a converter as a power conversion circuit. The converter is a DC-DC conversion circuit that converts a DC voltage into a DC voltage of a different value. The converter is provided between the DC power source 2 and the smoothing capacitor 5. The converter is configured to include, for example, a reactor and the above-mentioned upper and lower arm circuits 9. With this configuration, voltage can be increased and decreased. The power conversion device 4 may include a filter capacitor that removes power supply noise from the DC power source 2. The filter capacitor is provided between the DC power source 2 and the converter.

[0022] The power conversion device 4 may include a drive circuit for a switching element constituting the inverter 6 or the like. The drive circuit supplies a drive voltage to the gate of the IGBT 11 of the corresponding arm based on a drive command from the control circuit. The drive circuit drives the corresponding IGBT 11, i.e., turns it on and off, by applying the drive voltage. The drive circuit is sometimes referred to as a driver.

[0023] The power conversion device 4 may include a control circuit for the switching element. The control circuit generates a drive command for operating the IGBT 11 and outputs it to the drive circuit. The control circuit generates the drive command based on a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. The various sensors include, for example, a current sensor, a rotation angle sensor, and a voltage sensor. The current sensor detects a phase current flowing through the winding 3a of each phase. The rotation angle sensor detects the rotation angle of the rotor of the motor generator 3. The voltage sensor detects the voltage across the smoothing capacitor 5. The control circuit outputs, for example, a PWM signal as the drive command. The control circuit is configured to include, for example, a processor and a memory. ECU is an abbreviation for Electronic Control Unit. PWM is an abbreviation for Pulse Width Modulation.

[0024] <Semiconductor device> Next, a schematic configuration of the semiconductor device 20 will be described with reference to FIGS. 2 to 7. FIG. 2 is a plan view showing the semiconductor device 20. FIG. 3 is a plan view showing the semiconductor device 20 shown in FIG. 2 without the sealing body 30. FIG. 4 is a plan view showing the semiconductor device 20 shown in FIG. 3 without a part of the heat sinks 50 and 60. FIG. 5 is a plan view explaining the heat sinks 60H and 60L and the external connection terminal 90. FIG. 6 is a cross-sectional view taken along the line VI-VI shown in FIG. 2. FIG. 7 is a cross-sectional view taken along the line VII-VII shown in FIG. 2. FIG. 8 is an enlarged view of the heat sink 50L connected to the emitter electrode of the second semiconductor element 41L. FIG. 9 is an enlarged view of the heat sink 50H connected to the emitter electrode of the first semiconductor element 41H. FIG. 10 is an enlarged view of the joint portion 81 connected to the heat sink 50H in FIG. 9. FIG. 11 is an enlarged view of the joint portion 82 connected to the heat sink 50L in FIG. 10. In addition, in FIG. 3, dashed lines are drawn at the same positions as the cross-sectional lines in FIG.

[0025] Some of the elements constituting the semiconductor device 20 are designated by the suffix "H" indicating the upper arm 9H side and "L" indicating the lower arm 9L side. Other elements are designated by the same reference numerals for both the upper arm 9H and the lower arm 9L for convenience.

[0026] In the following, the thickness direction of the semiconductor element (semiconductor substrate) is defined as the Z direction. The direction perpendicular to the Z direction is defined as the X direction. The direction perpendicular to both the Z direction and the X direction is defined as the Y direction. Unless otherwise specified, the shape viewed from the Z direction, in other words the shape along the XY plane defined by the X and Y directions, is defined as the planar shape. The planar view from the Z direction is sometimes simply referred to as planar view. The X direction corresponds to the lateral direction. The Z direction corresponds to the overlap direction. The planar direction corresponds to the first arrangement direction or the second arrangement direction.

[0027] The semiconductor device 20 includes a sealing body 30, two semiconductor elements 40, heat sinks 50 and 60, two conductive spacers 70, joints 80 to 82, and an external connection terminal 90. The semiconductor device 20 further includes a bonding wire 97, solder 100, a first covering member 110, and a second covering member 120. The semiconductor device 20 constitutes the upper and lower arm circuits 9 for one phase described above.

[0028] The sealing body 30 seals a part of the other elements constituting the semiconductor device 20. The remaining parts of the other elements are exposed to the outside of the sealing body 30. The sealing body 30 is made of, for example, a resin. An example of the resin is an epoxy resin. The sealing body 30 is made of a resin and molded by, for example, a transfer molding method. Such a sealing body 30 may be called a sealing resin body, a molded resin, a resin molded body, or the like. The sealing body 30 may be formed by using, for example, a gel. The gel is filled in, for example, the opposing regions of the heat sinks 50 and 60.

[0029] As shown in FIG. 2, the sealing body 30 has a substantially rectangular shape in plan view. The sealing body 30 has one surface 30a and a back surface 30b opposite to the one surface 30a in the Z direction as surfaces forming an outer periphery. The back surface 30b may be referred to as an outer surface. The one surface 30a and the back surface 30b are, for example, substantially flat surfaces. The sealing body 30 also has side surfaces 30c, 30d, 30e, and 30f connected to the one surface 30a and the back surface 30b. The side surface 30c is a surface from which the main terminals 91 to 93 of the external connection terminals 90 protrude. The main terminals 91 to 93 may be simply referred to as the external connection terminals 90. The side surface 30d is a surface opposite to the side surface 30c in the Y direction. The side surface 30d is a surface from which the signal terminals 94 protrude. The side surfaces 30e and 30f are surfaces from which the external connection terminals 90 do not protrude. The side surface 30e is the surface opposite to the side surface 30f in the X direction.

[0030] The semiconductor element 40 includes a semiconductor substrate 41, an emitter electrode 42, a collector electrode 43, and a pad 44. The semiconductor element 40 is sometimes called a semiconductor chip. The semiconductor substrate 41 is made of materials such as silicon (Si) and a wide band gap semiconductor having a wider band gap than silicon, and a vertical element is formed on the semiconductor substrate 41. Examples of wide band gap semiconductors include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond.

[0031] The vertical element is configured to pass a main current in the thickness direction of the semiconductor substrate 41 (semiconductor element 40), i.e., in the Z direction. The vertical element of this embodiment is an IGBT 11 and a diode 12 that form one arm. The vertical element is an IGBT with a diode 12 connected in inverse parallel, that is, an RC-IGBT. RC is an abbreviation for Reverse Conducting. The vertical element is a heat generating element that generates heat when current is applied. A gate electrode (not shown) is formed on the semiconductor substrate 41. The gate electrode has, for example, a trench structure.

[0032] The semiconductor substrate 41 has a generally rectangular shape in plan view. An emitter electrode 42, which is one of the main electrodes, is disposed on one surface of the semiconductor substrate 41. A collector electrode 43, which is the other of the main electrodes, is disposed on the back surface of the semiconductor substrate 41. The one surface of the semiconductor substrate 41 is the surface of the main surface of the semiconductor substrate 41 that faces the one surface 30a of the sealing body 30 in the plate thickness direction. The back surface of the semiconductor substrate 41 is the surface of the main surface of the semiconductor substrate 41 that faces the back surface 30b of the sealing body 30 in the plate thickness direction.

[0033] When the IGBT 11 is turned on, a current (main current) flows between the main electrodes, that is, between the emitter electrode 42 and the collector electrode 43. The emitter electrode 42 also serves as the anode electrode of the diode 12. The collector electrode 43 also serves as the cathode electrode of the diode 12. The collector electrode 43 is formed on almost the entire back surface of the semiconductor substrate 41. The emitter electrode 42 is formed on a portion of one surface of the semiconductor substrate 41. That is, in a plan view, the collector electrode 43 has a larger area than the emitter electrode 42. The emitter electrode 42 corresponds to an upper electrode, and the collector electrode 43 corresponds to a lower electrode.

[0034] The emitter electrode 42 has a Ni layer formed using a material mainly composed of Ni (nickel). The emitter electrode 42 of this embodiment has an Al layer formed using a material mainly composed of Al (aluminum) and a Ni layer laminated on the Al layer. Like the emitter electrode 42, the collector electrode 43 also has an Al layer and a Ni layer.

[0035] The pads 44 are electrodes for signals. The pads 44 are formed in a region on one surface of the semiconductor substrate 41 that is different from the region where the emitter electrode 42 is formed. The pads 44 are formed at an end on the opposite side in the Y direction from the region where the emitter electrode 42 is formed. The pads 44 are provided side by side with the emitter electrode 42 in the Y direction. The number of pads 44 is not particularly limited. The pads 44 include at least a pad for a gate electrode.

[0036] As an example, the semiconductor element 40 has five pads 44. Specifically, there are pads for a gate electrode, for detecting an emitter potential, for detecting a cathode potential of a temperature sensing diode (not shown) included in the semiconductor element 40, for detecting an anode potential of the same, and for sensing a current. The five pads 44 are aligned along the X direction.

[0037] The semiconductor device 20 includes two semiconductor elements 40. Specifically, the semiconductor element 40H constitutes the upper arm 9H, and the semiconductor element 40L constitutes the lower arm 9L. The semiconductor element 40H may be referred to as a first semiconductor element, an upper arm element, etc. The semiconductor element 40L may be referred to as a second semiconductor element, a lower arm element, etc. The semiconductor elements 40H and 40L have the same specifications, that is, are common members. The semiconductor elements 40H and 40L are aligned in the X direction. The semiconductor elements 40H and 40L are disposed at approximately the same position in the Z direction. The semiconductor elements 40H and 40L are disposed so that one surface of each of the semiconductor elements 40H and 40L, that is, the emitter electrodes 42 of each of the semiconductor elements 40H and 40L are located on the same side in the Z direction.

[0038] The heat sink 50 is electrically connected to the emitter electrode 42 and provides a wiring function. Similarly, the heat sink 60 is electrically connected to the collector electrode 43 and provides a wiring function. The heat sinks 50, 60 provide a heat dissipation function for dissipating heat generated by the semiconductor element 40. For this reason, the heat sinks 50, 60 are sometimes referred to as wiring members, conductive members, heat dissipation members, etc. The heat sinks 50, 60 are arranged to sandwich the semiconductor element 40 in the Z direction. The heat sinks 50, 60 are arranged so that at least a portion of each of them faces each other in the Z direction. The heat sinks 50, 60 contain the semiconductor element 40 in a plan view.

[0039] The heat sinks 50 and 60 are metal plates made of a metal with good electrical conductivity, such as Cu or a Cu alloy. The metal plate is provided, for example, as a part of a lead frame. A first coating member 110 is provided on the surface of the heat sinks 50 and 60. The surface of the heat sink 50 corresponds to the outer surface including the opposing surface 50a, the rear surface 50b, and the side surface 50c connecting the opposing surface 50a and the rear surface 50b, which will be described later. The surface of the heat sink 60 corresponds to the outer surface including the opposing surface 60a, the rear surface 60b, and the side surface 60c connecting the opposing surface 60a and the rear surface 60b, which will be described later.

[0040] The first covering member 110 is formed by performing a plating process or the like on the surfaces of the heat sinks 50, 60. As an example, the first covering member 110 is made of Ni or the like, which is resistant to rust and has good corrosion resistance. Furthermore, the heat sink 50 is provided with a second covering member 120 so as to cover a part of the first covering member 110. The location of the second covering member 120 will be described in detail later.

[0041] The second coating member 120 is formed by performing a plating process or the like on the surface of the first coating member 110. As an example, the second coating member 120 is made of Au or the like, which has a lower solder wettability than Ni. The surface tension of the second coating member 120 is higher than the surface tension of the first coating member 110. Note that the first coating member 110 and the second coating member 120 are not limited to Ni and Au. As long as the solder wettability of the second coating member 120 is lower than the solder wettability of the first coating member 110, a plating material other than Ni and Au may be used.

[0042] The heat sink 50 has an opposing surface 50a, which is the surface on the semiconductor element 40 side, and a back surface 50b, which is the surface opposite to the opposing surface 50a. The opposing surface 50a may be referred to as an upper opposing surface. Similarly, the heat sink 60 also has an opposing surface 60a and a back surface 60b. The back surfaces 50b and 60b of the heat sinks 50 and 60, respectively, are exposed from the sealing body 30. The back surfaces 50b and 60b may be referred to as a heat dissipation surface, an exposed surface, or the like. The back surface 50b of the heat sink 50 is approximately flush with one surface 30a of the sealing body 30. The back surface 60b of the heat sink 60 is approximately flush with the back surface 30b of the sealing body 30.

[0043] The semiconductor device 20 includes two heat sinks 50. Specifically, the semiconductor device 20 includes a heat sink 50H that constitutes the upper arm 9H and a heat sink 50L that constitutes the lower arm 9L. The heat sink 50H corresponds to a first upper conductor, and the heat sink 50L corresponds to a second upper conductor.

[0044] The heat sinks 50H, 50L are generally rectangular in plan view. The heat sinks 50H, 50L are aligned in the X direction. As shown in Figs. 6 and 7, the heat sinks 50H, 50L have substantially the same thickness and are disposed at substantially the same positions in the Z direction. The heat sinks 50H, 50L contain the corresponding semiconductor elements 40 and conductive spacers 70 in plan view. The back surfaces 50b of the heat sinks 50H, 50L exposed from the sealing body 30 are aligned in the X direction.

[0045] The semiconductor device 20 further includes two heat sinks 60. Specifically, the semiconductor device 20 includes a heat sink 60H constituting the upper arm 9H and a heat sink 60L constituting the lower arm 9L. The heat sink 60H corresponds to a first lower conductor, and the heat sink 60L corresponds to a second lower conductor.

[0046] The heat sinks 60H, 60L are generally rectangular in plan view. The heat sinks 60H, 60L are aligned in the X direction. As shown in Figs. 6 and 7, the heat sinks 60H, 60L have substantially the same thickness and are disposed at substantially the same positions in the Z direction. The heat sinks 60H, 60L contain the corresponding semiconductor elements 40 in plan view. The back surfaces 60b of the heat sinks 60H, 60L exposed from the sealing body 30 are aligned in the X direction.

[0047] The conductive spacer 70 is interposed between the semiconductor element 40 and the heat sink 50 in the Z direction. The conductive spacer 70 provides a spacer function that ensures a predetermined distance between the semiconductor element 40 and the heat sink 50. For example, the conductive spacer 70 ensures a height for electrically connecting the corresponding signal terminal 94 to the pad 44 of the semiconductor element 40. The conductive spacer 70 is located midway along the electrical conduction and thermal conduction paths between the emitter electrode 42 of the semiconductor element 40 and the heat sink 50, and provides a wiring function and a heat dissipation function. The conductive spacer 70, together with the heat sink 50, constitutes an upper conductor.

[0048] The conductive spacer 70 is a metal member made of a metal such as Cu having good electrical conductivity and thermal conductivity. The conductive spacer 70 may be called a terminal, a terminal block, a metal block, or the like. The conductive spacer 70 has a first covering member 110 formed on its surface by plating or the like. The conductive spacer 70 has the first covering member 110 on at least the solder joint surface. The conductive spacer 70 of this embodiment is a columnar body having a substantially rectangular shape in plan view and having substantially the same size as the emitter electrode 42.

[0049] The semiconductor device 20 includes two conductive spacers 70. Specifically, the semiconductor device 20 includes a conductive spacer 70H that constitutes the upper arm 9H, and a conductive spacer 70L that constitutes the lower arm 9L.

[0050] The semiconductor device 20 includes a plurality of solders 100 for connecting elements. The solders 100 include solders 101H, 101L, 102H, 102L, 103H, 103L, 104, and 105. The solder 101H is interposed between the emitter electrode 42 of the semiconductor element 40H and the conductive spacer 70H, and joins the emitter electrode 42 and the conductive spacer 70H. The solder 102H is interposed between the conductive spacer 70H and the heat sink 50H, and joins the conductive spacer 70H and the heat sink 50H. The solder 103H is interposed between the collector electrode 43 of the semiconductor element 40H and the heat sink 60H, and joins the collector electrode 43 and the heat sink 60H.

[0051] The solder 101L is interposed between the emitter electrode 42 of the semiconductor element 40L and the conductive spacer 70L, and bonds the emitter electrode 42 and the conductive spacer 70L. The solder 102L is interposed between the conductive spacer 70L and the heat sink 50L, and bonds the conductive spacer 70L and the heat sink 50L. The solder 103L is interposed between the collector electrode 43 of the semiconductor element 40L and the heat sink 60L, and bonds the collector electrode 43 and the heat sink 60L. The solders 103H and 103L correspond to the lower solder. The solders 102H and 102L are sometimes referred to as upper solder.

[0052] The solder 104, together with the joints 80 and 81, electrically connects the heat sink 50H and the heat sink 60L. The solder 104 of this embodiment is interposed between the joint 80 connected to the heat sink 60L and the joint 81 connected to the heat sink 50H, and joins the joints 80 and 81. The solder 105, together with the joint 82, electrically connects the heat sink 50L and the main terminal 92. The solder 105 of this embodiment is interposed between the joint 82 connected to the heat sink 50L and the connection portion 920 of the main terminal 92, and joins the joint 82 and the main terminal 92. The solder 104 may be referred to as relay solder.

[0053] The heat sinks 50H and 50L have grooves 51H and 51L recessed from the opposing surface 50a toward the back surface 50b. The grooves 51H and 51L are sometimes referred to as upper grooves. The grooves 51H and 51L are provided so as to surround the desired area surfaces 52H and 52L of the heat sinks 50H and 50L in an annular shape, where solder connection with the conductive spacers 70H and 70L is desired. In other words, the grooves 51H and 51L are provided so as to surround the desired area surfaces 52H and 52L of the heat sinks 50H and 50L in an annular shape, where electrical connection with the semiconductor elements 40H and 40L is desired. The desired area surfaces 52H and 52L are surfaces where the solder 102H and 102L are desired to spread. The desired area surfaces 52H and 52L are substantially rectangular in plan view. As an example, the desired range surfaces 52H, 52L are included within the Z-direction projection areas of the conductive spacers 70H, 70L. The desired range surfaces 52H, 52L may be provided beyond the Z-direction projection areas of the conductive spacers 70H, 70L. The desired range surfaces 52H, 52L may be referred to as upper solder desired range surfaces.

[0054] The grooves 51H, 51L are holes for retaining the solder 102H, 102L to prevent the solder 102H, 102L from spreading beyond the desired area surfaces 52H, 52L. The grooves 51H, 51L are sometimes referred to as notches cut into the heat sinks 50H, 50L.

[0055] In the heat sink 50H, 50L, the portion having the desired range surface 52H, 52L on the surface may be referred to as the desired range portion 53H, 53L. The desired range portion 53H, 53L may also be referred to as the upper solder desired range portion. The desired range portion 53H, 53L is adjacent to the groove 51H, 51L in the planar direction. The desired range portion 53H, 53L defines a part of the groove 51H, 51L. The desired range portion 53H, 53L has the desired range surface 52H, 52L and the side surface 54H, 54L that defines a part of the groove 51H, 51L on the opposing surface 50a side. The angle of the corner portion 55H, 55L formed by the side surface 54H, 54L and the desired range surface 52H, 52L in the desired range portion 53H, 53L is a right angle. The angle of corners 55H, 55L is not limited to 90 degrees, and may be approximately right angles such as 89 degrees, 91 degrees, etc. Corners 55H, 55L may be referred to as upper solder desired area corners.

[0056] The grooves 51H and 51L are substantially trapezoidal with respect to the XZ plane. The grooves 51H and 51L are defined by side surfaces 54H and 54L, opposing side surfaces 56H and 56L that face the side surfaces 54H and 54L in the planar direction, and bottom surfaces 57H and 57L that connect the side surfaces 54H and 54L and the opposing side surfaces 56H and 56L. The bottom surfaces 57H and 57L face the openings 58H and 58L of the grooves 51H and 51L in the Z direction. The side surfaces 54H and 54L, the opposing side surfaces 56H and 56L, and the bottom surfaces 57H and 57L may be collectively referred to as the surfaces of the grooves 51H and 51L. The surfaces of the grooves 51H and 51L are all part of the heat sinks 50H and 50L. The heat sinks 50H, 50L have side surfaces 54H, 54L, opposing side surfaces 56H, 56L, and bottom surfaces 57H, 57L on the opposing surface 50a side. The bottom surfaces 57H, 57L may be referred to as first bottom surfaces. The openings 58H, 58L may be referred to as first openings.

[0057] Only the first covering member 110 is provided on the surfaces of the grooves 51H, 51L. The second covering member 120 is not provided on the surfaces of the grooves 51H, 51L. The second covering member 120 is not provided on the surfaces of the grooves 51H, 51L. Since the second covering member 120 is not provided on the surfaces of the grooves 51H, 51L, the solder 102H, 102L pooled in the grooves 51H, 51L does not easily spread in a direction away from the desired range surfaces 52H, 52L.

[0058] Furthermore, the width L2 of the openings 58H, 58L of the grooves 51H, 51L in the arrangement direction in which the side surfaces 54H, 54L and the opposing side surfaces 56H, 56L are arranged is smaller than twice the width L1 of the bottom surfaces 57H, 57L in the arrangement direction. The width L2 of the openings 58H, 58L in the arrangement direction is set to be larger than the width L1 of the bottom surfaces 57H, 57L in the arrangement direction. It is desirable that the width L1 of the bottom surfaces 57H, 57L in the arrangement direction is 0.2 mm or more in consideration of mold manufacturability. Furthermore, in order to ensure the mold can be removed from the grooves 51H, 51L, an incline is provided on the opposing corners 59H, 59L that face the corners 55H, 55L in the arrangement direction. The incline of the opposing corners 59H, 59L is a taper to ensure the mold can be removed. In order to ensure the storage of solder 102H, 102L and the manufacturability of the mold, it is desirable that corners 55H, 55L are right angles and opposing corners 59H, 59L are tapered. The depth of grooves 51H, 51L in the Z direction may be deep enough to capture solder 102. Opposing corners 59H, 59L are sometimes referred to as first opposing corners.

[0059] The joints 80-82 connect the elements that make up the upper and lower arm circuits 9. The joints 80-82 connect the elements that make up the semiconductor device 20. The joints 80-82 are metal members made of a metal such as Cu that has good electrical and thermal conductivity. The joints 80-82 have a first coating member 110 formed on the surface thereof by plating or the like. The joints 80-82 have the first coating member 110 at least on the solder joint surface.

[0060] The joint part 80 is connected to the heat sink 60L. The joint part 80 extends from the heat sink 60L toward the heat sink 50H. The thickness of the joint part 80 is thinner than that of the heat sink 60L. The joint part 80 is connected to the opposing surface (side surface) of the heat sink 60H, for example, in a state where it is substantially flush with the opposing surface 60a of the heat sink 60L. The joint part 80 has two bent parts, and thus forms a substantially crank shape in the ZX plane. The joint part 80 is covered by the sealing body 30.

[0061] The joint portion 80 may be continuous and integral with the heat sink 60L, or may be provided as a separate member and connected by bonding. The joint portion 80 of this embodiment is integral with the heat sink 60L as a part of the lead frame. The first covering member 110 is continuous and integral with the heat sink 60L and the joint portion 80.

[0062] The joints 81, 82 are connected to the corresponding heat sink 50. The joint 81 is connected to the heat sink 50H. The joint 82 is connected to the heat sink 50L. The joint 81 extends from the heat sink 50H toward the heat sink 50L. The joint 82 extends from the heat sink 50L toward the heat sink 50H. The joints 81, 82 are thinner than the corresponding heat sink 50. The joints 81, 82 are covered by the sealing body 30.

[0063] The joints 81 and 82 may be connected by being provided continuously and integrally with the heat sink 50, or may be provided as separate members and connected by bonding. The joints 81 and 82 of this embodiment are provided integrally with the corresponding heat sinks 50H and 50L. The joints 81 and 82 extend in the X direction from the opposing side surfaces of the heat sinks 50H and 50L. The length of the joint 81 in the X direction is almost equal to the length of the joint 82 in the X direction. The first covering member 110 is provided continuously and integrally with the heat sink 50H and the joint 81. The first covering member 110 is provided continuously and integrally with the heat sink 50L and the joint 82.

[0064] As an example, the heat sink 50H including the joint portion 81 and the heat sink 50L including the joint portion 82 are common components. The arrangement of the heat sink 50H including the joint portion 81 and the heat sink 50L including the joint portion 82 are two-fold symmetric with the Z axis as the rotation axis. Solder 104 is interposed between the opposing surfaces of the joint portion 80 and the joint portion 81 to form a solder joint. The joint portions 81 and 82 are arranged between the heat sinks 50H and 50L in a plan view. The joint portions 81 and 82 are lined up in the Y direction between the heat sinks 50H and 50L. The joint portion 81 corresponds to the first extension portion. The joint portion 80 corresponds to the second extension portion. The joint portion 82 corresponds to the third extension portion.

[0065] <Groove in the joint connected to the heat sink on the upper arm side> The joint part 81 has an opposing surface 81a, which is the surface on the semiconductor element 40 side, and a back surface 81b, which is the surface opposite to the opposing surface 81a. The joint part 81 has a groove 131 recessed from the opposing surface 81a toward the back surface 81b. The groove 131 may be called an extended groove. The opposing surface 81a may be called an extended opposing surface. The groove 131 is provided so as to surround a desired range surface 132 in the joint part 81 where a solder connection with the joint part 80 is desired. The solder 104, together with the joint parts 80 and 81, electrically connects the heat sink 50H and the heat sink 60L. The solder 104 is interposed between the joint part 80 connected to the heat sink 60L and the joint part 81 connected to the heat sink 50H, and joins the joint parts 80 and 81. The groove 131 is a hole for retaining the solder 104 to prevent the solder 104 from spreading beyond a desired area surface 132. The groove 131 may also be referred to as a notch cut into the joint portion 81.

[0066] In the joint portion 81, a portion having the desired range surface 132 on its surface may be referred to as the desired range portion 133. The desired range portion 133 is adjacent to the groove 131 in the planar direction. The desired range portion 133 defines a portion of the groove 131. The desired range portion 133 has the desired range surface 132 and a side surface 134 that defines a portion of the groove 131 on the opposing surface 81a side. The angle of the corner portion 135 formed by the side surface 134 and the desired range surface 132 in the desired range portion 133 is a right angle. The angle of the corner portion 135 is not limited to 90 degrees, and may be an approximately right angle, such as 89 degrees or 91 degrees.

[0067] The groove 131 is substantially trapezoidal with respect to the XZ plane. The groove 131 is defined by a side surface 134, an opposing side surface 136 that faces the side surface 134 in a planar direction, and a bottom surface 137 that connects the side surface 134 and the opposing side surface 136. The bottom surface 137 faces an opening 138 of the groove 131 in the Z direction. The side surface 134, the opposing side surface 136, and the bottom surface 137 may be collectively referred to as the surface of the groove 131. All of the surfaces of the groove 131 are part of the joint portion 81. The joint portion 81 has the side surface 134, the opposing side surface 136, and the bottom surface 137 on the opposing surface 81a side. The bottom surface 137 may be referred to as a second bottom surface. The opening 138 may be referred to as a second opening.

[0068] Only first covering member 110 is provided on the surface of groove 131. Second covering member 120 is not provided on the surface of groove 131. Second covering member 120 is not provided on the surface of groove 131. Since second covering member 120 is not provided on the surface of groove 131, solder 104 pooled in groove 131 does not easily wet and spread in a direction away from desired area surface 132.

[0069] Moreover, the width L4 of the opening 138 of the groove 131 in the arrangement direction in which the side surface 134 and the opposing side surface 136 are arranged is smaller than twice the width L3 of the bottom surface 137 in the arrangement direction. The width L4 of the opening 138 in the arrangement direction is set to be larger than the width L3 of the bottom surface 137 in the arrangement direction. The width L3 of the bottom surface 137 in the arrangement direction is desirably 0.2 mm or more in consideration of mold manufacturability. Furthermore, in order to ensure the mold can be removed from the groove 131, an inclination is provided at the opposing corner 139 that faces the corner 135 in the arrangement direction. The inclination of the opposing corner 139 is a taper to ensure the mold can be removed from the mold. In order to ensure the storage property of the solder 104 and the mold manufacturability, it is desirably that the corner 135 is a right angle and the opposing corner 139 is tapered. The depth of the groove 131 in the Z direction may be deep enough to capture the solder 104. The opposing corner 139 may be called a second opposing corner. The opposing corners 139 may be referred to as corners of the desired solder joint area.

[0070] <Groove on the joint connected to the heat sink on the lower arm side> Similarly, the joint part 82 has an opposing surface 82a, which is the surface on the semiconductor element 40 side, and a back surface 82b, which is the surface opposite to the opposing surface 82a. The joint part 82 has a groove 141 recessed from the opposing surface 82a toward the back surface 82b. The groove 141 is provided so as to surround a desired range surface 142 in which a solder connection with the connection part 920 in the joint part 82 is desired in an annular shape. The solder 105 electrically connects the heat sink 50L and the main terminal 92 together with the joint part 82. The opposing surface 82a may be referred to as a terminal opposing surface. The solder 105 may be referred to as a terminal connection solder. The solder 105 is interposed between the joint part 82 connected to the heat sink 50L and the connection part 920 of the main terminal 92, and joins the joint part 82 and the main terminal 92. Groove 141 is a reservoir hole for solder 105 to prevent solder 105 from spreading beyond desired range surface 142. Groove 141 may be referred to as a notch cut into joint portion 82. Groove 141 may be referred to as a terminal facing groove. Desired range surface 142 may be referred to as a terminal connection solder desired range surface.

[0071] In the joint portion 82, a portion having the desired range surface 142 on its surface may be referred to as the desired range portion 143. The desired range portion 143 may be referred to as the terminal connection solder desired range portion. The desired range portion 143 is adjacent to the groove 141 in the planar direction. The desired range portion 143 defines a part of the groove 141. The desired range portion 143 has the desired range surface 142 and a side surface 144 that defines a part of the groove 141 on the opposing surface 82a side. The angle of the corner portion 145 formed by the side surface 144 and the desired range surface 142 in the desired range portion 143 is a right angle. The angle of the corner portion 145 is not limited to 90 degrees, and may be approximately a right angle such as 89 degrees or 91 degrees. The corner portion 145 may be referred to as the terminal connection solder desired range corner portion.

[0072] The groove 141 is substantially trapezoidal with respect to the XZ plane. The groove 141 is defined by a side surface 144, an opposing side surface 146 that faces the side surface 144 in the planar direction, and a bottom surface 147 that connects the side surface 144 and the opposing side surface 146. The bottom surface 147 faces an opening 148 of the groove 141 in the Z direction. The side surface 144, the opposing side surface 146, and the bottom surface 147 may be collectively referred to as the surface of the groove 141. All of the surfaces of the groove 141 are part of the joint portion 82. The joint portion 82 has the side surface 144, the opposing side surface 146, and the bottom surface 147 on the opposing surface 82a side.

[0073] Only first covering member 110 is provided on the surface of groove 141. Second covering member 120 is not provided on the surface of groove 141. Second covering member 120 is not provided on the surface of groove 141. Since second covering member 120 is not provided on the surface of groove 141, solder 105 pooled in groove 141 does not easily wet and spread in a direction away from desired area surface 142.

[0074] Furthermore, the width L6 of the opening 148 of the groove 141 in the arrangement direction in which the side surface 144 and the opposing side surface 146 are arranged is smaller than twice the width L5 of the bottom surface 147 in the arrangement direction. The width L6 of the opening 148 in the arrangement direction is set to be larger than the width L5 of the bottom surface 147 in the arrangement direction. The width L5 of the bottom surface 147 in the arrangement direction is desirably 0.2 mm or more in consideration of mold manufacturability. Furthermore, in order to ensure the mold can be removed from the groove 141, an inclination is provided at the opposing corner 149 that faces the corner 145 in the arrangement direction. It is desirable that the inclination of the opposing corner 149 is such that the corner 145 is a right angle and the opposing corner 149 is tapered in order to ensure the mold can be removed. The depth of the groove 141 in the Z direction may be deep enough to capture the solder 105.

[0075] <External connection terminal> The external connection terminals 90 are terminals for electrically connecting the semiconductor device 20 to an external device. The external connection terminals 90 are formed using a metal material with good conductivity, such as copper. The external connection terminals 90 are, for example, a plate material. The external connection terminals 90 are sometimes called leads. The external connection terminals 90 include main terminals 91, 92, and 93, and a signal terminal 94. The main terminals 91, 92, and 93 are external connection terminals 90 electrically connected to main electrodes of the semiconductor element 40.

[0076] The main terminal 91 is electrically connected to the collector electrode 43 of the semiconductor element 40H. The main terminal 91 is electrically connected to the positive terminal of the smoothing capacitor 5. The main terminal 91 may be referred to as a P terminal, a high potential power supply terminal, or the like. The main terminal 91 is connected to the collector electrode 43 of the semiconductor element 40H via the heat sink 60H. The main terminal 91 is connected to one end of the heat sink 60H in the Y direction. The thickness of the main terminal 91 is thinner than that of the heat sink 60H. The main terminal 91 is connected to the heat sink 60H so as to be substantially flush with the opposing surface 60a, for example. The main terminal 91 may be connected to the heat sink 60H by being provided integrally and continuously with the heat sink 60H, or may be provided as a separate member and connected by joining.

[0077] The main terminal 91 in this embodiment is provided integrally with the heat sink 60H as a part of the lead frame. The main terminal 91 extends in the Y direction from the heat sink 60H and protrudes to the outside from the side surface 30c of the sealing body 30. The main terminal 91 has a bent portion midway through the portion covered by the sealing body 30, and protrudes from near the center in the Z direction on the side surface 30c.

[0078] The main terminal 92 is electrically connected to the emitter electrode 42 of the semiconductor element 40L. The main terminal 92 is electrically connected to the negative terminal of the smoothing capacitor 5. The main terminal 92 may be referred to as an N terminal, a low potential power supply terminal, or the like. The main terminal 92 is connected to the emitter electrode 42 of the semiconductor element 40L via the joint portion 82, the heat sink 50L, and the conductive spacer 70L. The main terminal 92 extends in the Y direction and protrudes outside the sealing body 30 from the same side surface 30c as the main terminal 91.

[0079] The main terminal 92 has a connection portion 920 with the joint portion 82 near one end in the Y direction. A portion of the main terminal 92 including the connection portion 920 is covered by the sealing body 30, and the remaining portion protrudes from the sealing body 30. The connection portion 920 has a plate thickness greater than the portion protruding from the sealing body 30. The plate thickness of the connection portion 920 is, for example, approximately the same as that of the heat sink 50L. The main terminal 92 also has a bent portion like the main terminal 91, and protrudes from near the center in the Z direction on the side surface 30c. The main terminal 92 has a first coating member 110 formed on the surface by plating or the like. The main terminal 92 has the first coating member 110 at least on the solder joint surface of the connection portion 920.

[0080] The main terminal 93 is connected to a connection point between the upper arm 9H and the lower arm 9L. The main terminal 93 is electrically connected to the emitter electrode 42 of the semiconductor element 40H and the collector electrode 43 of the semiconductor element 40L. The main terminal 93 is electrically connected to the winding 3a of the corresponding phase of the motor generator 3. The main terminal 93 may be referred to as an output terminal, an AC terminal, an O terminal, etc. The main terminal 93 is electrically connected to the emitter electrode 42 of the semiconductor element 40H via the heat sink 60L, the joint parts 80 and 81, the heat sink 50H, and the conductive spacer 70H. The main terminal 93 is connected to the collector electrode 43 of the semiconductor element 40L via the heat sink 60L.

[0081] The main terminal 93 is connected to one end of the heat sink 60L in the Y direction. The thickness of the main terminal 93 is thinner than that of the heat sink 60L. The main terminal 93 is connected to the heat sink 60L so as to be substantially flush with the opposing surface 60a, for example. The main terminal 93 may be connected by being integrally provided continuously with the heat sink 60L, or may be provided as a separate member and connected by joining.

[0082] The main terminal 93 in this embodiment is provided integrally with the heat sink 60L as a part of the lead frame. The main terminal 93 extends in the Y direction from the heat sink 60L and protrudes out of the sealing body 30 from the same side surface 30c as the main terminal 91. The main terminal 93 also has a bent portion like the main terminal 91, and protrudes from near the center in the Z direction on the side surface 30c. The three main terminals 91 to 93 are arranged in the X direction in the order of main terminal 91, main terminal 92, and main terminal 93.

[0083] The signal terminals 94 are electrically connected to the corresponding pads 44 of the semiconductor element 40. In this embodiment, the signal terminals 94 are electrically connected to the pads 44 via bonding wires 97. The signal terminals 94 extend in the Y direction and protrude from the side surface 30d of the sealing body 30 to the outside. The semiconductor device 20 includes five signal terminals 94 for one semiconductor element 40, that is, a total of ten signal terminals 94. The multiple signal terminals 94 are arranged side by side in the X direction. The signal terminals 94 are formed on a lead frame common to the heat sink 60 and the main terminals 91 to 93, for example.

[0084] The semiconductor device 20 includes a hanging lead 95. The heat sink 60 (60H, 60L), the joint portion 80, the main terminals 91 to 93, and the signal terminal 94 are configured in a lead frame, which is a common member. The lead frame has an irregular shape with thicknesses varying in parts. Before being cut, the signal terminal 94 is supported by the hanging lead 95 via a tie bar (not shown). Unnecessary portions of the lead frame, such as the tie bar and the peripheral frame, are cut (removed) after the sealing body 30 is formed.

[0085] As described above, in the semiconductor device 20, the multiple semiconductor elements 40 that configure the upper and lower arm circuits 9 for one phase are encapsulated by the encapsulant 30. The encapsulant 30 integrally encapsulates the multiple semiconductor elements 40, parts of the heat sinks 50, parts of the heat sinks 60, the conductive spacer 70, the joints 80-82, the main terminals 91-93, and parts of the signal terminals 94.

[0086] <Method of Manufacturing Semiconductor Device> Next, a method for manufacturing the semiconductor device 20 will be described. The method for manufacturing the semiconductor device 20 is composed of a plurality of steps. The semiconductor device 20 is manufactured through a preparation step, a stacking step, a layering step, a sealing step, and a frame cutting step. First, the preparation step will be described.

[0087] Fig. 12 is a flow chart for explaining the manufacturing method. Fig. 13 is a cross-sectional view for explaining the stacking step in the manufacturing process. Fig. 14 is a plan view for explaining the stacking step in the manufacturing process.

[0088] The preparation step prepares the elements that make up the semiconductor device 20. The heat sinks 60H, 60L, the joint portion 80, the main terminals 91 to 93, the signal terminal 94, the suspension lead 95, and a lead frame including tie bars (not shown) that connect these are prepared.

[0089] After the preparation process, a stacking process is performed. In the stacking process, the semiconductor elements 40H, 40L are placed on the mounting surfaces of the heat sinks 60H, 60L via the solders 103H, 103L. The semiconductor elements 40H, 40L are placed on the solders 103H, 103L so that the collector electrodes 43 are on the mounting surface side. Next, the conductive spacers 70H, 70L are placed on the emitter electrodes 42 via the solders 101H, 101L. The solders 102H, 102L are placed on the surfaces of the conductive spacers 70H, 70L opposite to the semiconductor elements 40H, 40L. The solders 102H, 102L may be provided in advance as back-up solder on the conductive spacers 70H, 70L. Although not shown, the solder 104 is placed on the same side of the connecting portion 920 as the mounting surface.

[0090] In this laminated state, a first reflow is performed. As a result, the collector electrodes 43 of the semiconductor elements 40H, 40L are connected to the heat sinks 60H, 60L via the solders 103H, 103L. Also, the emitter electrodes 42 of the semiconductor elements 40H, 40L are connected to the corresponding conductive spacers 70H, 70L via the solders 101H, 101L. That is, a first connection body 150 in which the lead frame, the semiconductor elements 40H, 40L, and the conductive spacers 70H, 70L are integrated can be obtained. The solders 102H, 102L in the first connection body 150 become the receiving solder to be used in a later process.

[0091] Although not shown, in the stacking process, the pads 44 of the semiconductor elements 40H, 40L are electrically connected to the signal terminals 94. In this embodiment, the pads of the semiconductor elements 40H, 40L are connected to the signal terminals 94 by bonding wires 97.

[0092] After the stacking step, a layering step is performed. In the layering step, the heat sinks 50H, 50L are placed on a pedestal (not shown). Then, the first connection body 150 is placed on the heat sinks 50H, 50L so that the mounting surface on the conductive spacers 70H, 70L side faces downward. In this arranged state, a second reflow is performed. The heat sinks 50H, 50L are integrated with the first connection body 150 by the second reflow. The heat sinks 50H, 50L are integrated with the first connection body 150 to form the second connection body 160.

[0093] After the overlapping step, a sealing step is performed. In the sealing step, the sealing body 30 is formed. In this embodiment, a transfer molding method is adopted. The second connector 160 is placed in a mold, and the sealing body 30 is molded. In this embodiment, the sealing body 30 is molded so that the rear surfaces 50b, 60b of the heat sinks 50, 60 are exposed to the outside.

[0094] After the sealing process, a frame cutting process is performed in which unnecessary parts of the lead frame, such as the outer frame and tie bars, are removed from the second connection body 160. In this manner, the semiconductor device 20 can be obtained.

[0095] <Action and effect> The semiconductor device 20 includes semiconductor elements 40H and 40L, heat sinks 50 and 60, solder 100, a first covering member 110, and a second covering member 120. The semiconductor elements 40H and 40L are aligned in the X direction. The heat sink 50 is electrically connected to the emitter electrodes 42 of the semiconductor elements 40H and 40L via solders 102H and 102L. The heat sink 60 is electrically connected to the collector electrodes 43 of the semiconductor elements 40H and 40L via solders 103H and 103L. The surfaces of the heat sinks 50 and 60 are covered by the first covering member 110. The heat sinks 50H and 50L are further covered by the second covering member 120 so as to cover a part of the first covering member 110. More specifically, desired area surfaces 52H, 52L of the heat sinks 50H, 50L where solder connection to the semiconductor elements 40H, 40L is desired are covered with the second covering member 120. The second covering member 120 is made of a material having lower wettability with the solder 100 than the first covering member 110.

[0096] The semiconductor device of this embodiment is formed by stacking the heat sinks 50H, 50L via the solder 102H, 102L on a structure in which the semiconductor elements 40H, 40L and the heat sinks 60H, 60L are soldered together. In this embodiment, the second coating member 120 is provided only on the desired area surfaces 52H, 52L of the heat sinks 50H, 50L, so that the solder 102H, 102L is contained within the desired area surfaces 52H, 52L. This suppresses the spread of the solder 102H, 102L. It is possible to suppress the occurrence of dimensional defects such as misalignment of the semiconductor elements 40H, 40L.

[0097] The heat sinks 50H and 50L have grooves 51H and 51L recessed from the opposing surface 50a toward the back surface 50b. The grooves 51H and 51L are provided so as to surround the desired range surfaces 52H and 52L in an annular shape. The parts having the desired range surfaces 52H and 52L on their surfaces may be referred to as desired range portions 53H and 53L. The desired range portions 53H and 53L are adjacent to the grooves 51H and 51L in the planar direction. The desired range portions 53H and 53L define a part of the grooves 51H and 51L. The angles of the corners 55H and 55L formed by the side surfaces 54H and 54L and the desired range surfaces 52H and 52L in the desired range portions 53H and 53L are right angles. In addition, only the first covering member 110 is provided on the surfaces of the grooves 51H and 51L. The second covering member 120 is not provided on the surfaces of the grooves 51H and 51L.

[0098] Since the corners 55H, 55L are right angles and the second coating member 120 is not provided on the surfaces of the grooves 51H, 51L, the solder 102H, 102L does not easily spread to the side surfaces 54H, 54L on the corners 55H, 55L side. Therefore, the movement of the solder 102H, 102L is easily stopped. Also, the solder 102H, 102L that remains in the grooves 51H, 51L is not easily creeping up to the opposing side surfaces 56H, 56L. Therefore, the solder 102H, 102L is easily retained in the grooves 51H, 51L. In this way, in this embodiment, the solder 102H, 102L that overflows by a predetermined amount or more is retained in the grooves 51H, 51L, and the semiconductor elements 40H, 40L can be solder-connected to the heat sinks 50H, 50L by the predetermined amount of the solder 102H, 102L. It is possible to suppress the occurrence of dimensional defects such as misalignment of the semiconductor elements 40H, 40L.

[0099] The joint portion 81 is connected to the heat sink 50H. The joint portion 81 extends from the heat sink 50H toward the heat sink 50L. The joint portion 80 is connected to the heat sink 60L. The joint portion 80 extends from the heat sink 60L toward the heat sink 50H. The joint portion 81 and the joint portion 80 are connected via the solder 104. A desired area surface 132 of the joint portion 81 where a solder connection with the joint portion 80 is desired is covered with the second covering member 120. In this embodiment, since the second covering member 120 is provided only on the desired area surface 132 of the joint portion 81, the solder 104 is contained within the range of the desired area surface 132. This suppresses the spread of the solder 105.

[0100] The joint part 81 has a groove 131 recessed from the opposing surface 81a toward the back surface 81b. The groove 131 is provided so as to surround a desired range surface 132 in an annular shape where a solder connection with the joint part 80 in the joint part 81 is desired. In the joint part 81, a portion having the desired range surface 132 on its surface may be referred to as a desired range portion 133. The desired range portion 133 may be referred to as a relay solder desired range portion. The desired range portion 133 is adjacent to the groove 131 in the planar direction. The desired range portion 133 defines a part of the groove 131. The angle of the corner portion 135 formed by the side surface 134 and the desired range surface 132 in the desired range portion 133 is a right angle. In addition, only the first covering member 110 is provided on the surface of the groove 131. The second covering member 120 is not provided on the surface of the groove 131. The desired area surface 132 may be referred to as the relay solder desired area surface.

[0101] Since the corner 135 is a right angle and the second covering member 120 is not provided on the side surface 134, the solder 105 does not easily spread to the side surface 134 on the corner 135 side. Therefore, the movement of the solder 104 is easily stopped. Furthermore, the solder 104 that remains in the groove 131 is also not easily creeping up to the opposing side surface 136. Therefore, the solder 104 is easily retained in the groove 131. Since the overflowing solder 105 can be retained in the groove 131 and the joint portion 80 and the joint portion 81 can be soldered and connected by a predetermined amount of solder 105, the occurrence of dimensional defects such as misalignment can be suppressed. The semiconductor elements 40H, 40L are connected to the heat sinks 50H, 50L via a predetermined amount of solder 102H, 102L, and the joint portion 81 is connected to the joint portion 80 via a predetermined amount of solder 105. This makes it possible to prevent dimensional defects such as misalignment in the height direction between the heat sinks 50H, 50L and the joint portion 81. The semiconductor device 20 is prevented from tilting in the height direction.

[0102] Unlike the present embodiment, when the grooves 51H, 51L are U-shaped and the second covering member 120 covers the entire surface including the grooves 51H, 51L, the solder 102H, 102L tends to actively enter and exit the grooves 51H, 51L. In that case, the solder 102H, 102L tends to spread in the planar direction beyond the desired range surface 132, and the thickness of the solder 102H, 102L is unlikely to differ significantly, so that the Z-direction positional deviation of the semiconductor elements 40H, 40L is unlikely to occur for each semiconductor device 20. However, since the solder 102H, 102L wets and spreads in the planar direction, there is a concern that the semiconductor elements 40H, 40L may be misaligned in the planar direction, and it has been difficult to suppress dimensional defects such as misalignment of the semiconductor device 20.

[0103] In contrast, in this embodiment, the solders 102H, 102L are unlikely to spread beyond the desired range surface 132 in the planar direction. As a result, the semiconductor elements 40H, 40L are unlikely to be misaligned in the planar direction. Furthermore, in this embodiment, the thicknesses of the solders 102H, 102L are unlikely to differ significantly. As a result, the semiconductor elements 40H, 40L are unlikely to be misaligned in the Z direction for each semiconductor device 20. In this embodiment, dimensional defects such as misalignment of the semiconductor device 20 can be suppressed in any direction.

[0104] Also, unlike this embodiment, in the case where the U-shaped grooves 51H, 51L and the rectangular groove 131 are provided and the second covering member 120 covers the entire surface including the grooves 51H, 51L, 131, the thickness of the solder 104 may be thinner than the thickness of the solder 102H, 102L. In that case, the joint portion 82 may tilt so as to rise up from the heat sink 50H. In this embodiment, the grooves 51H, 51L, 131 and the application range of the second covering member 120 are limited, so that the thicknesses of the solder 104, 102H, 102L are designed to be predetermined. Therefore, in this embodiment, the semiconductor device 20 is prevented from tilting in the height direction.

[0105] As described above, the opposing corners 59H, 59L of the heat sinks 50H, 50L facing the corners 55H, 55L in the arrangement direction are inclined. The opposing corners 139 facing the corners 135 of the joint portion 81 in the arrangement direction are inclined. The widths L2, L4 of the openings 58H, 58L of the grooves 51H, 51L in the arrangement direction are shorter than twice the widths L1, L3 of the bottom surfaces 57H, 57 of the grooves 51H, 51L in the arrangement direction. The width L6 of the opening 138 of the groove 131 in the arrangement direction is shorter than twice the width L5 of the bottom surface 137 of the groove 131 in the arrangement direction. This prevents the opposing corners 59H, 59L from being less than 45 degrees. The draft angle of the opposing corners 139 is prevented from being less than 45 degrees. Therefore, the solder that has dropped into the grooves 51H, 51L, and 131 is less likely to creep up the walls of the opposing corners 59H, 59L, and 139. The solder is prevented from creeping up the walls of the opposing corners 59H, 59L, and 139 and overflowing from the grooves 51H, 51L, and 131.

[0106] The joint portion 82 is connected to the heat sink 50L. The joint portion 82 extends from the heat sink 50L toward the heat sink 50H. The joint portion 82 and the main terminal 92 are connected via solder 105. A desired area surface 142 of the joint portion 82 where a solder connection with the main terminal 92 is desired is covered with the second covering member 120. In this embodiment, since the second covering member 120 is provided only on the desired area surface 142 of the joint portion 82, the solder 105 is contained within the range of the desired area surface 142. This suppresses the solder 105 from spreading.

[0107] The joint part 82 has a groove 141 recessed from the opposing surface 82a toward the back surface 82b. The groove 141 is provided so as to surround a desired range surface 142 in an annular shape where a solder connection with the main terminal 92 of the joint part 82 is desired. In the joint part 82, a portion having the desired range surface 142 on its surface may be referred to as a desired range part 143. The desired range part 143 is adjacent to the groove 141 in the planar direction. The desired range part 143 defines a part of the groove 141. The angle of the corner part 145 formed by the side surface 144 and the desired range surface 142 in the desired range part 143 is a right angle. In addition, only the first covering member 110 is provided on the surface of the groove 141. The second covering member 120 is not provided on the surface of the groove 141.

[0108] Since the corner 145 is a right angle and the second covering member 120 is not provided on the side 144, the solder 105 does not easily spread to the side 144 on the corner 145 side. Therefore, the movement of the solder 105 is easily stopped. Furthermore, the solder 105 that remains in the groove 141 is also not easily creeping up to the opposing side 146. Therefore, the solder 105 is easily retained in the groove 141. Since the overflowing solder 105 can be retained in the groove 141 and the joint portion 82 and the main terminal 92 can be soldered and connected by a predetermined amount of solder 105, the occurrence of dimensional defects such as positional deviation can be suppressed. Since the joint portion 82 is connected to the main terminal 92 via a predetermined amount of solder 105, the occurrence of dimensional defects such as positional deviation between the joint portion 82 and the main terminal 92 can be suppressed.

[0109] Second embodiment Fig. 15 is a plan view showing the semiconductor device 20 of the second embodiment. Fig. 16 is a cross-sectional view showing the semiconductor device 20 of the second embodiment. The desired range surfaces 52H, 52L are surfaces on which the wetting and spreading of the solders 102H, 102L is desired. In the first embodiment, the desired range surfaces 52H, 52L are included within the Z-direction projection areas of the conductive spacers 70H, 70L. In the second embodiment, the desired range surfaces 52H, 52L are provided beyond the Z-direction projection areas of the conductive spacers 70H, 70L.

[0110] As an example, the desired range surfaces 52H, 52L are expanded toward the signal terminal 94 in the Y direction. This makes the thickness of the solder 102H, 102L on the signal terminal 94 side thinner than the thickness of the solder 102H, 102L on the main terminal 91 side. The swelling of the solder 102H, 102L on the signal terminal 94 side is suppressed. In addition, the solder 102H, 102L on the signal terminal 94 side overlaps with the bonding wire 97 in the Z direction. In the second embodiment, since the thickness of the solder 102H, 102L on the signal terminal 94 side is thin, the bonding wire 97 is unlikely to come into contact with the solder 102H, 102L. In this way, the desired range surfaces 52H, 52L can be appropriately changed according to the design.

[0111] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more than one, or less than one element are also within the scope and concept of the present disclosure. [Explanation of symbols]

[0112] 100 solder, 102H, 102L upper solder, 103H, 103L lower solder, 104 relay solder, 105 terminal connection solder, 110 first covering member, 120 second covering member, 131 extension groove, 132 relay solder desired area surface, 133 relay solder desired area portion, 137 second bottom surface, 138 second opening, 139 relay solder desired area corner portion, 139 second opposing corner portion, 141 terminal facing groove, 142 terminal connection solder desired area surface, 143 terminal connection solder desired area portion, 145 terminal connection solder desired area corner portion, 40 Semiconductor element, 40H First semiconductor element, 40L Second semiconductor element, 42 Upper electrode, 43 Lower electrode, 5 Electrical component, 50H First upper conductor, 50H upper conductor, 50L second upper conductor, 50L upper conductor, 50a upper opposing surface, 51H, 51L upper groove, 52H, 52L upper solder desired area surface, 53H, 53L upper solder desired area portion, 55H, 55L upper solder desired area corner portion, 57H, 57L first bottom surface, 58H, 58L first opening, 59H, 59L first opposing corner portion, 60H 1st bottom conductor, 60H bottom conductor, 60L 2nd bottom conductor, 60L bottom conductor, 80 2nd extension part, 81 1st extension part, 81a extension opposing surface, 82 3rd extension part, 82a terminal opposing surface, 92 main terminal, L1, L2, L3, L4 width, X horizontal direction, Z overlapping direction.

Claims

1. A semiconductor element (40) including a first semiconductor element (40H) and a second semiconductor element (40L) having an upper electrode (42) and a lower electrode (43), the first semiconductor element (40H) and the second semiconductor element (40L) arranged in a lateral direction (X) that is a direction perpendicular to an overlapping direction (Z) in which the upper electrode and the lower electrode overlap; an upper conductor (50H, 50L) having a first upper conductor (50H) overlapping the upper electrode of the first semiconductor element and a second upper conductor (50L) overlapping the upper electrode of the second semiconductor element; a bottom conductor (60H, 60L) having a first bottom conductor (60H) overlapping the bottom electrode of the first semiconductor element and a second bottom conductor (60L) overlapping the bottom electrode of the second semiconductor element; A solder (100) having an upper solder (102H, 102L) that connects the upper electrode of the semiconductor element and the upper conductor, and a lower solder (103H, 103L) that connects the lower electrode of the semiconductor element and the lower conductor; a first covering member (110) covering the upper conductor and the lower conductor; a second coating member (120) that covers a portion of the first coating member and through which the solder is less likely to spread than the first coating member; The semiconductor device, wherein the second covering member is placed on an upper solder desired area surface (52H, 52L) where connection to the semiconductor element by the upper solder is desired in the upper conductor.

2. The upper conductor has the upper solder desired area surface, and has an upper opposing surface (50a) facing the semiconductor element, and an upper groove (51H, 51L) recessed from the upper opposing surface, the upper groove is adjacent to the upper solder desired area surface and extends annularly so as to surround the upper solder desired area surface; an upper solder desired area portion (53H, 53L) of the upper conductor overlapping the upper solder desired area surface in the overlapping direction defines a part of the upper groove; The angle of the upper solder desired area corner portion (55H, 55L) which is a corner that defines the upper groove in the upper solder desired area portion is a right angle, The semiconductor device according to claim 1 , wherein the second covering member is not provided in the upper groove.

3. a first extension portion (81) extending from the first upper conductor toward the second upper conductor; a second extension portion (80) extending from the second lower conductor toward the first upper conductor and connected to the first extension portion, The solder further includes a relay solder (104) that connects the first extension portion and the second extension portion, 3. The semiconductor device according to claim 2, wherein the second coating member is disposed on a desired relay solder area surface (132) of the first extension portion where connection with the second extension portion by the relay solder is desired.

4. The first extension portion has the relay solder desired area surface, and has an extension groove (131) that is a groove recessed from the extended opposing surface (81a) that is a surface facing the second extension portion, The extension groove is adjacent to the relay solder desired area surface and extends annularly so as to surround the relay solder desired area surface, A relay solder desired area portion (133) of the first extension portion overlapping the relay solder desired area surface in the overlapping direction defines a part of the extension groove, The angle of the relay solder desired area corner portion (139), which is a corner that defines the extension groove in the relay solder desired area portion, is a right angle, The semiconductor device according to claim 3 , wherein the second covering member is not provided in the extension groove.

5. a first opposing corner portion (59H, 59L) of the upper conductor that faces the upper solder desired area corner portion in a first arrangement direction in which the upper groove and the upper solder desired area are arranged is inclined; A second opposing corner portion (139) of the first extension portion that faces the corner portion of the relay solder desired area in a second arrangement direction in which the extension groove and the relay solder desired area are arranged is inclined, A width (L2) of a first opening (58H, 58L) of the upper groove in the first arrangement direction is shorter than twice the width (L1) of a first bottom surface (57H, 57L) of the upper groove in the first arrangement direction. The semiconductor device of claim 4, wherein a width (L3) of a second opening (138) of the extension groove in the second alignment direction is shorter than twice a width (L4) of a second bottom surface (137) of the extension groove in the second alignment direction.

6. a third extension (82) extending from the second upper conductor toward the first upper conductor; and a main terminal (92) for connecting the semiconductor element and an electrical component (5), The solder further includes a terminal connection solder (105) that connects the third extension portion and the main terminal, 6. The semiconductor device according to claim 5, wherein the second covering member is disposed on a terminal connection solder desired area surface (142) where connection with the main terminal by the terminal connection solder is desired in the third extension portion.

7. The third extension portion has the terminal connection solder desired area surface, and has a terminal facing surface (82a) facing the main terminal, the terminal facing surface having a terminal facing groove (141) recessed from the terminal facing surface, The terminal facing groove is adjacent to the terminal connection solder desired area surface and extends annularly so as to surround the terminal connection solder desired area surface, A terminal connection solder desired area portion (143) of the third extension portion overlapping the terminal connection solder desired area surface in the overlapping direction defines a part of the terminal facing groove, The angle of the terminal connection solder desired area corner portion (145), which is a corner that defines the terminal facing groove in the terminal connection solder desired area portion, is a right angle, The semiconductor device according to claim 6 , wherein the second covering member is not provided in the terminal facing groove.

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