阅读说明：本技术 半导体装置 (Semiconductor device with a plurality of semiconductor chips ) 是由 大前翔一朗 石野宽 于 2020-02-13 设计创作，主要内容包括：半导体装置具备：半导体元件(40),在一面侧具有第1主电极(41C),在背面侧具有第2主电极(41E)；与一面侧的第1主电极连接的第1散热部件(50C)及背面侧的第2散热部件(50E)；以及引线框(60),包括与第1散热部件连接的第1主端子(61C)以及与第2主电极连接的第2主端子(61E)。第2主端子具有与第2主电极连接的连接部(62E)、从连接部延伸设置且与第1散热部件对置的对置部(64E)、以及与连接部相反地与对置部相连且与第1主端子在正交于厚度方向的一个方向上排列的非对置部(65E)。第2散热部件经由第2主端子而与半导体元件连接。引线框中第1主端子以及第2主端子的非对置部的至少一方具有多个。非对置部以侧面相互对置的方式交替地排列,对置的侧面的组形成有多个。(The semiconductor device includes: a semiconductor element (40) having a 1 st main electrode (41C) on one surface side and a 2 nd main electrode (41E) on the back surface side; a 1 st heat dissipating member (50C) connected to the 1 st main electrode on the one surface side and a 2 nd heat dissipating member (50E) on the back surface side; and a lead frame (60) including a 1 st main terminal (61C) connected to the 1 st heat sink member and a 2 nd main terminal (61E) connected to the 2 nd main electrode. The 2 nd main terminal has a connecting portion (62E) connected to the 2 nd main electrode, an opposing portion (64E) extending from the connecting portion and opposing the 1 st heat dissipating member, and a non-opposing portion (65E) opposite to the connecting portion, connected to the opposing portion, and aligned with the 1 st main terminal in one direction orthogonal to the thickness direction. The 2 nd heat dissipation member is connected to the semiconductor element via the 2 nd main terminal. The lead frame has a plurality of non-opposing portions of the 1 st main terminal and the 2 nd main terminal. The non-facing portions are alternately arranged so that the side surfaces face each other, and a plurality of sets of facing side surfaces are formed.)

1. A semiconductor device is characterized in that a semiconductor element,

the disclosed device is provided with:

at least one semiconductor element (40) having, as a main electrode (41), a 1 st main electrode (41C) on one surface side and a 2 nd main electrode (41E) on the back surface side, the back surface being the surface opposite to the one surface in the thickness direction;

a 1 st heat dissipation member (50C) and a 2 nd heat dissipation member (50E) which are heat dissipation members (50) arranged so as to sandwich the semiconductor element, the 1 st heat dissipation member being arranged on the one surface side and connected to the 1 st main electrode, the 2 nd heat dissipation member being arranged on the back surface side; and

a lead frame (60) including a 1 st main terminal (61C) and a 2 nd main terminal (61E) as main terminals (61) electrically connected to the corresponding main electrodes, the 1 st main terminal being connected to the 1 st heat dissipating member, the 2 nd main terminal being connected to the 2 nd main electrode;

the 2 nd main terminal includes:

a connecting part (62E) connected with the 2 nd main electrode;

an opposing portion (64E) that is a portion extending from the connecting portion, is continuous with the connecting portion, and is opposed to the 1 st heat dissipation member; and

a non-opposing portion (65E) connected to the opposing portion opposite to the connecting portion, and arranged in a direction orthogonal to the thickness direction with respect to the 1 st main terminal;

the 2 nd heat dissipating member is connected to the semiconductor element via the 2 nd main terminal;

a plurality of lead frames, each of which has a plurality of non-opposing portions, at least one of the 1 st main terminal and the 2 nd main terminal;

the non-facing portions of the 1 st main terminal and the 2 nd main terminal are alternately arranged with side surfaces facing each other, and a plurality of sets of the side surfaces facing each other are formed.

2. The semiconductor device according to claim 1,

the 2 nd main terminal includes a plurality of the non-opposing portions and one of the connecting portions integrally provided with the plurality of the non-opposing portions.

3. The semiconductor device according to claim 2,

the facing portion is integrally provided with respect to the plurality of non-facing portions over at least a part of the range in the extending direction.

4. The semiconductor device according to any one of claims 1 to 3,

the semiconductor element has a signal pad (42) formed on the back surface side;

the lead frame includes a signal terminal (67) electrically connected to the pad.

5. The semiconductor device according to claim 4,

the signal terminal is connected to the pad via a bonding member (83).

6. The semiconductor device according to claim 4 or 5,

in the lead frame, the signal terminal is thinner than the 2 nd main terminal;

the facing distance between the signal terminal and the 1 st heat dissipation member is longer than the facing distance between the 2 nd main terminal and the 1 st heat dissipation member.

7. The semiconductor device according to any one of claims 1 to 6,

in a plan view seen from the thickness direction, the 1 st heat dissipation member has an overlapping portion (51C) overlapping with the 2 nd heat dissipation member, and a non-overlapping portion (52C) continuous with the overlapping portion and not overlapping with the 2 nd heat dissipation member;

the 1 st main terminal is connected to the non-overlapping portion of an opposing surface (500C) of the 1 st heat dissipation member that opposes the 2 nd heat dissipation member.

Technical Field

The present invention relates to a semiconductor device.

Background

Patent document 1 proposes a semiconductor device. The semiconductor device includes a semiconductor element having a 1 st main electrode and a 2 nd main electrode, a heat dissipation member disposed so as to sandwich the semiconductor element, and a main terminal electrically connected to the corresponding main electrode.

The semiconductor device includes, as heat dissipation members, a 1 st heat dissipation member disposed on a 1 st main electrode side and a 2 nd heat dissipation member disposed on a 2 nd main electrode side. The semiconductor device includes, as main terminals, a 1 st main terminal electrically connected to a 1 st main electrode and a 2 nd main terminal electrically connected to a 2 nd main electrode.

Documents of the prior art

Patent document

Patent document 1: JP 2015-82614A

Disclosure of Invention

In the semiconductor device of patent document 1, the 1 st main terminal extends from the 1 st heat dissipation member, and the 2 nd main terminal extends from the 2 nd heat dissipation member. The 1 st heat dissipation member is connected to the 1 st main electrode, and the 2 nd heat dissipation member is connected to the 2 nd main electrode via a terminal (terminal). The semiconductor element and the terminal are interposed between the 1 st heat sink member and the 2 nd heat sink member. The semiconductor device has 1 st main terminal and 2 nd main terminal, respectively. A further reduction of the inductance is required.

The invention provides a semiconductor device capable of reducing inductance.

According to one aspect of the present invention, a semiconductor device includes: at least one semiconductor element having, as main electrodes, a 1 st main electrode on one surface side and a 2 nd main electrode on a back surface side, the back surface being a surface opposite to the one surface in a thickness direction; a 1 st heat dissipation member and a 2 nd heat dissipation member arranged to sandwich the semiconductor element, the 1 st heat dissipation member being arranged on one surface side and connected to the 1 st main electrode, the 2 nd heat dissipation member being arranged on the back surface side; and a lead frame including a 1 st main terminal and a 2 nd main terminal as main terminals electrically connected to the corresponding main electrodes, the 1 st main terminal being connected to the 1 st heat dissipating member, the 2 nd main terminal being connected to the 2 nd main electrode.

In the semiconductor device, the 2 nd main terminal has: a connection part connected with the 2 nd main electrode; an opposing portion extending from the connecting portion, connected to the connecting portion, and opposing the 1 st heat dissipating member; and a non-opposing portion connected to the opposing portion opposite to the connecting portion, and arranged in a direction orthogonal to the thickness direction with respect to the 1 st main terminal. The 2 nd heat dissipation member is connected to the semiconductor element via the 2 nd main terminal. In the lead frame, at least one of the non-opposing portions of the 1 st main terminal and the 2 nd main terminal has a plurality of portions. The non-facing portions of the 1 st main terminal and the 2 nd main terminal are alternately arranged with side surfaces facing each other, and a plurality of sets of the side surfaces facing each other are formed.

According to one aspect of the present invention, in the semiconductor device, the lead frame including the main terminal is provided as a member different from the heat dissipation member. The 2 nd main terminal is disposed between the 2 nd heat dissipating member and the semiconductor element, and is connected to the 2 nd electrode. The 1 st heat sink member is a portion having the same potential as the 1 st main electrode. The facing portion of the 2 nd main terminal is closest to the portion of the 1 st heat sink member having the same potential as the 2 nd main electrode. The non-facing portions of the 1 st main terminal and the 2 nd main terminal are alternately arranged so that the side surfaces thereof face each other. The 1 st main terminal and the 2 nd main terminal (non-opposing portion) are formed in sets having a plurality of sets of opposing side surfaces. As a result, a semiconductor device capable of reducing inductance can be provided.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

Fig. 1 is a diagram showing a schematic configuration of a power conversion device to which a semiconductor device according to embodiment 1 is applied.

Fig. 2 is a perspective view showing the semiconductor device.

Fig. 3 is a perspective view showing elements in the sealing resin body.

Fig. 4 is a plan view of fig. 2 viewed from a direction a.

Fig. 5 is a plan view of fig. 3 as viewed from the direction B.

Fig. 6 is a sectional view taken along line VI-VI of fig. 2.

Fig. 7 is a sectional view taken along line VII-VII of fig. 2.

Fig. 8 is a perspective view showing a connection state of the lead frame.

Fig. 9 is a perspective view showing a positional relationship between the heat sinks and the lead frame.

Fig. 10 is a cross-sectional view showing a comparative example.

Fig. 11 is a graph showing the decrease in inductance.

Fig. 12 is a graph showing the decrease in inductance.

Fig. 13 is a plan view showing a modification.

Fig. 14 is a schematic plan view showing a modification.

Fig. 15 is a diagram showing a decrease in thermal resistance.

Fig. 16 is a plan view showing the semiconductor device according to embodiment 2, and corresponds to fig. 5.

Fig. 17 is a cross-sectional view showing the periphery of a semiconductor element in the semiconductor device according to embodiment 3.

Fig. 18 is a cross-sectional view showing a modification.

Detailed Description

Various embodiments are described with reference to the drawings. In various embodiments, functionally and/or structurally corresponding parts are assigned the same reference signs. Hereinafter, the thickness direction of the semiconductor element is referred to as the Z direction, and one direction orthogonal to the Z direction is referred to as the X direction. In addition, a direction orthogonal to both the Z direction and the X direction is represented as a Y direction. Unless otherwise specified, the shape along the XY plane defined by the above-described X direction and Y direction is taken as a planar shape.

(embodiment 1)

First, a power conversion device to which the semiconductor device is applied will be described with reference to fig. 1.

< schematic configuration of Power conversion device >

The power conversion device 1 shown in fig. 1 is mounted on, for example, an electric vehicle or a hybrid vehicle. The power conversion device 1 converts a dc voltage supplied from a dc power supply 2 mounted on a vehicle into a three-phase ac voltage and outputs the three-phase ac voltage to a three-phase ac motor 3. The motor 3 functions as a travel drive source of the vehicle. The power conversion device 1 can convert the electric power generated by the motor 3 into a direct current and charge the direct current power supply 2. The motor 3 having the power generation function is sometimes referred to as a motor generator. The power conversion device 1 can perform bidirectional power conversion.

The power conversion device 1 includes a smoothing capacitor 4 and an inverter 5 as a power converter. The smoothing capacitor 4 has a positive electrode-side terminal connected to a positive electrode, which is a high potential-side electrode of the dc power supply 2, and a negative electrode-side terminal connected to a negative electrode, which is a low potential-side electrode of the dc power supply 2. The inverter 5 converts the input dc power into a three-phase ac power of a predetermined frequency, and outputs the three-phase ac power to the motor 3. The inverter 5 converts the ac power generated by the motor 3 into dc power. The inverter 5 is a DC-AC conversion unit.

The inverter 5 includes a three-phase upper and lower arm circuit 6. Two arms are connected in series between a high potential power supply line 7 as a positive side power supply line and a low potential power supply line 8 as a negative side power supply line to form upper and lower arm circuits 6 of respective phases. In the upper and lower arm circuits 6 of each phase, a connection point of the upper arm and the lower arm is connected to an output line 9 for the motor 3.

In the present embodiment, an n-channel type insulated gate bipolar transistor 6i (hereinafter, referred to as an IGBT6i) is used as a switching element constituting each arm. Each IGBT6i is connected in antiparallel with the FWD6d as a freewheeling diode. The upper and lower arm circuit 6 of one phase has two IGBTs 6 i. In the upper arm, the collector electrode of IGBT6i is connected to high potential power supply line 7. In the lower arm, the emitter electrode of the IGBT6i is connected to the low-potential power supply line 8. The emitter electrode of the IGBT6i in the upper arm and the collector electrode of the IGBT6i in the lower arm are connected to each other.

The power conversion device 1 may further include a converter as a power converter other than the inverter 5, a drive circuit for the switching elements constituting the inverter 5 and the converter, and the like, in addition to the smoothing capacitor 4 and the inverter 5 described above. The converter is a DC-DC converter that converts a DC voltage into DC voltages of different values.

< semiconductor device >

As shown in fig. 2 to 9, the semiconductor device 20 includes a sealing resin body 30, a semiconductor element 40, a heat sink 50, and a lead frame 60 including a main terminal 61 and a signal terminal 67. Fig. 3 shows elements in the sealing resin body 30, as compared with fig. 2. In fig. 5, the sealing resin body 30 is omitted for convenience and is illustrated. Fig. 8 shows a connection state of the lead frame 60, specifically, a connection state with the semiconductor element 40 and a heat sink 50C described later. In fig. 9, the positional relationship of each heat sink 50 and the lead frame 60 is shown. Fig. 8 and 9 show the lead frame 60 in a state before the tie bar (tie bar) is cut.

The sealing resin body 30 seals a part of other elements constituting the semiconductor device 20. The remaining portions of the other elements are exposed to the outside of the sealing resin body 30. The sealing resin body 30 seals, for example, the semiconductor element 40. The sealing resin body 30 seals a connection portion formed between other elements constituting the semiconductor device 20. The sealing resin body 30 seals the connection portion between the semiconductor element 40 and the lead frame 60. The sealing resin body 30 seals the connection portion of the heat sink 50 and the lead frame 60. The sealing resin body 30 is sometimes referred to as a molding resin.

The sealing resin body 30 is made of, for example, an epoxy resin. The sealing resin body 30 is formed by, for example, transfer molding. As shown in fig. 2, 3, and 4, the sealing resin body 30 has one surface 300 and a back surface 301 opposite to the one surface 300 in the Z direction. The first surface 300 and the rear surface 301 are flat surfaces, for example. The sealing resin body 30 has a side surface connecting the first surface 300 and the rear surface 301. In the present embodiment, the planar shape of the sealing resin body 30 is substantially rectangular. The sealing resin body 30 has a side surface 302 and a side surface 303, the main terminal 61 protrudes outside the side surface 302, and the signal terminal 67 protrudes outside the side surface 303. The side surface 303 is a surface opposite to the side surface 302 in the Y direction.

The semiconductor element 40 is formed by forming elements on a semiconductor substrate of Si, SiC, GaN, or the like. The semiconductor device 20 includes at least one semiconductor element 40. In this embodiment, the IGBT6i and the FWD6d are formed on a semiconductor substrate constituting the semiconductor element 40. As described above, an rc (reverse connection) -IGBT is used as the semiconductor element 40. The semiconductor element 40 constitutes one of the arms described above. Semiconductor element 40 is sometimes referred to as a semiconductor chip.

The semiconductor element 40 has a vertical structure, and a main current flows in the Z direction. Although not shown, the semiconductor element 40 has a gate electrode. The gate electrode is, for example, of a trench configuration. As shown in fig. 6 and 7, the semiconductor element 40 has main electrodes 41 on both surfaces in the thickness direction thereof, i.e., the Z direction. A main current flows between the main electrodes 41. Specifically, the main electrode 41 includes a collector electrode 41C on one surface side and an emitter electrode 41E on the back surface side opposite to the one surface side. The collector electrode 41C also serves as a cathode electrode of the FWD6d, and the emitter electrode 41E also serves as an anode electrode of the FWD6 d. The collector electrode 41C is formed on substantially the entire area of one surface. The emitter electrode 41E is formed on a part of the rear surface. The collector electrode 41C corresponds to the 1 st main electrode, and the emitter electrode 41E corresponds to the 2 nd main electrode.

As shown in fig. 3 and 6, the semiconductor element 40 has a pad 42 serving as a signal electrode on the formation surface of the emitter electrode 41E. The pad 42 is formed at a position different from the emitter electrode 41E. The pad 42 is electrically separated from the emitter electrode 41E. The planar shape of the semiconductor element 40 is substantially rectangular. The pad 42 is formed at an end portion on the opposite side of the formation region of the emitter electrode 41E in the Y direction.

The semiconductor element 40 has, for example, 5 pads 42. Specifically, the pad 42 includes a pad for a gate electrode, a pad for detecting a potential of the emitter electrode 41E, a pad for sensing a current, and a pad for detecting a temperature of the semiconductor element 40. The pad 42 for temperature detection includes a pad for anode potential and a pad for cathode potential of a temperature sensing diode as a temperature detection element. The 5 pads 42 are formed in an array in the X direction.

As a constituent material of the electrodes such as the main electrode 41 and the pad 42, for example, an Al-based material can be used. In the case of bonding with solder or the like, the material preferably contains Cu. For example, AlCuSi may be used.

The heat sink 50 is a heat dissipation member arranged so as to sandwich the semiconductor element 40 in the Z direction. The heat sink 50 functions to dissipate heat generated by the semiconductor element 40. The heat sinks 50 are provided in pairs so as to sandwich the semiconductor element 40 in the Z direction. The semiconductor device 20 includes, as a pair of heat sinks 50, a heat sink 50C disposed on the collector electrode 41C side and a heat sink 50E disposed on the emitter electrode 41E side. The heat sink 50C corresponds to the 1 st heat dissipation member, and the heat sink 50E corresponds to the 2 nd heat dissipation member.

The heat sinks 50C, 50E are disposed so as to contain the semiconductor element 40 inside in a plan view viewed from the Z direction. The heat sink 50C has a mounting surface 500C on the semiconductor element 40 side and a heat dissipation surface 501C opposite to the mounting surface 500C in the Z direction. The heat sink 50E has a mounting surface 500E on the semiconductor element 40 side and a heat radiation surface 501E opposite to the mounting surface 500E in the Z direction. The mounting surfaces 500C and 500E face each other in the Z direction. The mounting surfaces 500C, 500E are substantially parallel to each other. The mounting surface 500C corresponds to an opposite surface of the 1 st heat sink member.

In the present embodiment, the planar shape of the heat sinks 50C, 50E is substantially rectangular. The length in the X direction is substantially uniform in the heat sinks 50C and 50E. With respect to the length in the Y direction, the heat sink 50C is longer than the heat sink 50E. As shown in fig. 3, 5, 6, etc., the heat sink 50C straddles the heat sink 50E in the Y direction. The heat sink 50C has an overlapping portion 51C and a non-overlapping portion 52C. The overlapping portion 51C is a portion overlapping with the heat sink 50E in a plan view viewed from the Z direction. The overlapping portion 51C is a region facing the mounting surface 500E of the heat sink 50E in the Z direction. The non-overlapping portion 52C is connected to the overlapping portion 51C on the main terminal 61 side in the Y direction. The non-overlapping portion 52C is a portion that does not overlap with the heat sink 50E.

Collector electrode 41C is connected to mounting surface 500C of heat sink 50C via bonding member 80. Collector electrode 41C is connected to overlapping portion 51C of heatsink 50C. Heat sink 50C is connected to main terminal 61 (main terminal 61C) corresponding to collector electrode 41C. The main terminal 61C is connected to the non-overlapping portion 52C of the heat sink 50C. Main terminal 61C is electrically connected to collector electrode 41C via heat sink 50C. The heat sink 50C functions as a wiring connecting the collector electrode 41C and the main terminal 61C.

Main terminal 61 (main terminal 61E) corresponding to emitter electrode 41E is connected to mounting surface 500E of heat sink 50E via bonding member 81. The main terminal 61E is connected to the emitter electrode 41E via a bonding member 82. The heat sink 50E is connected to the emitter electrode 41E via the bonding members 81 and 82 and the main terminal 61E. The main terminal 61E is electrically connected to the emitter electrode 41E without the heat sink 50E.

At least a part of each of the heat sinks 50C and 50E is sealed by the sealing resin 30. In the present embodiment, the heat dissipation surface 501C of the heat sink 50C is exposed from the sealing resin body 30. The heat dissipation surface 501C is substantially coplanar with the surface 300. The surface of heat sink 50C except for the connection with collector electrode 41C, heat radiation surface 501C, and the connection with main terminal 61C is covered with sealing resin 30. Similarly, the heat radiation surface 501E of the heat sink 50E is exposed from the sealing resin body 30. The heat dissipation surface 501E is substantially coplanar with the back surface 301. The surface of the heat sink 50E except for the connection portion with the main terminal 61E and the heat radiation surface 501E is covered with the sealing resin body 30.

As the heat sink 50, for example, a metal plate, a composite material of a metal body and an insulator can be used. Examples of the composite material include a dbc (direct Bonded coater) substrate. In the heat sink 50C and the heat sink 50E, the same kind of members may be used, or members different from each other may be used. In the present embodiment, as shown in fig. 3, 6, 7, and the like, a DBC substrate is used as the heat sinks 50C and 50E.

The heat sink 50 includes an insulator 50x and metal bodies 50y and 50z arranged to sandwich the insulator 50 x. The insulator 50x is a ceramic substrate. The metal bodies 50y and 50z are formed, for example, by containing Cu. The metal bodies 50y, 50z are directly bonded with respect to the insulator 50 x. The heat sink 50 includes a metal body 50y, an insulator 50x, and a metal body 50z stacked in this order from the semiconductor element 40 side. The heat sink 50 is of a 3-layer construction.

The planar shapes and sizes of the metal bodies 50y and 50z are substantially identical to each other. The planar shape of the insulator 50x as an intermediate layer is similar to the metal bodies 50y, 50 z. The insulator 50c is larger than the metal bodies 50y, 50 z. The insulator 50x extends to the outside of the metal bodies 50y and 50z over the entire circumference. In the heat sinks 50C and 50E, one surface of the metal body 50y serves as the mounting surfaces 500C and 500E. In the heat sinks 50C and 50E, one surface of the metal body 50z serves as heat radiation surfaces 501C and 501E.

The lead frame 60 includes external connection terminals. The external connection terminals electrically connect the arms with the outside of the semiconductor device 20. The outside of the semiconductor device 20 includes, for example, another semiconductor device 20 and the smoothing capacitor 4. The lead frame 60 includes a main terminal 61 and a signal terminal 67 as external connection terminals. The lead frame 60 is configured as a member different from the heat sink 50. The lead frame 60 is disposed between the heat sinks 50C, 50E in the Z direction. The lead frame 60 is formed by pressing a metal plate made of Cu or the like.

The main terminal 61 is an external connection terminal through which a main current flows. The lead frame 60 is provided with a plurality of main terminals 61. The main terminal 61 is electrically connected to the corresponding main electrode 41. As the main terminal 61, the semiconductor device 20 has a main terminal 61C electrically connected to the collector electrode 41C and a main terminal 61E electrically connected to the emitter electrode 41E. The main terminal 61C corresponds to the 1 st main terminal, and the main terminal 61E corresponds to the 2 nd main terminal. The main terminal 61C is sometimes referred to as a collector terminal. The main terminal 61E is sometimes referred to as an emitter terminal.

The main terminal 61 is sealed by the sealing resin 30 at a portion electrically connected to the main electrode 41. The main terminals 61 extend from the portions electrically connected to the main electrodes 41 in the Y direction away from the semiconductor element 40. All the main terminals 61 protrude outward from the side surface 302 of the sealing resin body 30.

As shown in fig. 3, 5, 7, and the like, the main terminal 61C has a connecting portion 62C and an extended portion 63C. The connection portion 62C is a portion of the main terminal 61C connected to the heat sink 50C. The main terminal 61C may be connected to the heat sink 50C via a bonding member such as solder. The main terminal 61C may be directly connected to the heat sink 50C by ultrasonic bonding, friction stir bonding, laser welding, or the like. The extension 63C is a portion extending from the connection portion 62C. The extension 63C is integrally connected to the connection 62C.

As shown in fig. 3, 5, 6, and the like, the main terminal 61E has a connecting portion 62E and an extended portion 63E. The connection portion 62E is a portion of the main terminal 61E connected to the emitter electrode 41E. As described above, the connection portion 62E of the main terminal 61E is connected to the emitter electrode 41E via the bonding member 82. The connection portion 62E is a portion overlapping with the emitter electrode 41E in a plan view viewed from the Z direction. The main terminal 61E includes a connection portion 62E and is connected to the heat sink 50E. In the connecting portion 62E, a joining member 81 is disposed on one surface side, and a joining member 82 is disposed on the opposite side of the one surface. At least a part of the engaging members 81, 82 overlap each other in a plan view seen from the Z direction.

The extension portion 63E is a portion extending from the connection portion 62E. The extension 63E is integrally connected to the connecting portion 62E. The extension portion 63C includes an opposing portion 64E and a non-opposing portion 65E. The opposing portion 64E is a portion opposing the heat sink 50C. The opposing portion 64E is opposed to the mounting surface 500C of the heat sink 50C in the Z direction. One end of the opposing portion 64E is connected to the connecting portion 62E, and the other end is connected to the non-opposing portion 65E.

The non-opposing portion 65E is a portion that does not oppose the heat sink 50C. The non-facing portion 65E extends from the facing portion 64E in a direction away from the semiconductor element 40. The non-facing portion 65E and the extended portion 63C of the main terminal 61C are arranged in a direction orthogonal to the Z direction. The extended portion 63C of the main terminal 61C and the non-opposing portion 65E of the main terminal 61E are disposed so that the side surfaces 610C and 610E face each other. A part of the extension portion 63C and a part of the non-opposing portion 65E are provided as connecting portions to be connected to the outside. The extension portion 63C and the non-opposing portion 65E are sometimes referred to as terminal portions. The lead frame 60 includes a plurality of main terminals 61C and/or non-opposing portions 65E.

The main terminals 61C and the non-opposing portions 65E are alternately arranged in the array direction. The alternation is an arrangement in which the main terminal 61C and the main terminal 61E are adjacent to each other in the arrangement direction. The main terminal 61C and the non-opposing portion 65E do not have plate surfaces opposing each other, but have side surfaces 610C and 610E opposing each other. By alternating the arrangement, the lead frame 60 has a plurality of sets of opposing side surfaces 610C, 610E. The side surfaces 610C and 610E may face at least a part of the main terminal 61 in the plate thickness direction. For example, the plate may be offset in the plate thickness direction. Preferably, one and the other of the side surfaces 710C, 710E facing each other are disposed so as to face each other over the entire region in the thickness direction.

In addition, the alternate minimum structure is a combination of two main terminals 61C and 1 non-opposing portion 65E, or a combination of 1 main terminal 61C and two non-opposing portions 65E. For example, in the case of two main terminals 61C and 1 non-opposing portion 65E, the main terminals 61C, the non-opposing portions 65E, and the main terminals 61C are arranged in the array direction. Two sets of mutually opposing side surfaces 610C, 610E are formed.

In the present embodiment, the lead frame 60 has 4 main terminals 61C and 5 non-opposing portions 65E. The thickness of the lead frame 60 is substantially uniform over the entire area. The plurality of main terminals 61C have substantially the same structure. The connection portion 62C of the main terminal 61C is ultrasonically bonded to the non-overlapping portion 52C in the mounting surface 500C of the heat sink 50C. The connection portion 62C is connected to the metal body 50y constituting the heat sink 50C. The connection portion 62C is connected to the mounting surface 500C near one end in the Y direction.

The extension setting portion 63C extends along the Y direction in a plan view in the Z direction. That is, the main terminal 61C extends in the Y direction in the plan view. The main terminal 61C extends to have a substantially constant width. The extension 63C has a curved portion. The extension 63C protrudes from the sealing resin body 30 at a position closer to the mounting surface 500E than the connection portion 62C in the Z direction. The main terminal 61C has a crank (crank) shape in the YZ plane.

The main terminal 61E has only one connection portion 62E. The main terminal 61E has a common connecting portion 62E integrally provided with the plurality of non-facing portions 65E. The lead frame 60 has 5 extending portions 63E. The extension portions 63E including the non-facing portion 65E are extended from the common one of the connection portions 62E. The plate surface of the extension 63E extending substantially parallel to the mounting surfaces 500C and 500E faces the mounting surfaces 500C and 500E. The plurality of facing portions 64E are arranged apart from each other in the X direction. The opposing portion 64E extends with a predetermined gap from the mounting surface 500E of the heat sink 50E. The sealing resin body 30 is provided between the facing portion 64E and the mounting surface 500E.

The plurality of non-facing portions 65E have substantially the same structure. The non-facing portion 65E is provided to extend in the Y direction with a substantially constant width. The width of the non-facing portion 65E is substantially the same as the width of the main terminal 61E. The non-facing portions 65E and the main terminals 61 are alternately arranged in the X direction. The non-facing portions 65E are disposed at both ends in the arrangement direction. The main terminal 61C and the non-opposing portion 65E are arranged at substantially the same position in the Z direction on the tip end side of the bent portion of the main terminal 61C. Substantially the entire surfaces of the side surfaces 610C and 610E face each other. As shown in fig. 4, the lead frame 60 has 8 sets of the side surfaces 610C and 610E facing each other. The facing distance between the side surfaces 610C and 610E, in other words, the pitch between the main terminal 61 and the non-facing portion 65E (2 nd main terminal 61E) is substantially constant.

As shown in fig. 8, the main terminals 61C and 61E are arranged line-symmetrically with respect to a center line CL passing through the center of the semiconductor element 40 in the X direction. The element center is the center of the semiconductor element 40 when there is one semiconductor element 40 as in the present embodiment. When there are two semiconductor elements 40, for example, the semiconductor elements are located at the center between the centers of the two semiconductor elements 40 in the arrangement direction. The center line CL is an imaginary line that is orthogonal to the X direction and passes through the center of the element.

The signal terminals 67 are electrically connected to the corresponding pads 42 of the semiconductor element 40. The lead frame 60 has a plurality of signal terminals 67. The signal terminals 67 are connected to the pads 42 inside the sealing resin body 30. The 5 signal terminals 67 connected to each pad 42 extend in the Y direction away from the semiconductor element 40. The signal terminals 67 are arranged in the X direction. All the signal terminals 67 protrude outward from the side surface 303 of the sealing resin body 30.

In the present embodiment, as shown in fig. 6, the signal terminal 67 is connected to the pad 42 via a bonding member 83. As the bonding members 80, 81, 82, 83, solder or conductive paste containing Ag or the like can be used. In the present embodiment, solder is used as the bonding members 80, 81, 82, and 83.

The lead frame 60 has suspension conductors 68. The lead frame 60 shown in fig. 8 and 9 has an outer peripheral frame 69 and tie bars 70 and 71 in a state before the tie bars are cut. The outer peripheral frame 69 is sometimes referred to as an outer peripheral frame. The connecting rod 70 extends in the X direction and is connected at both ends thereof to the outer peripheral frame 69. The plurality of signal terminals 67 are supported by the outer peripheral frame 69 by the connection bar 70. The suspension conductor 68 has one end connected to the connecting portion 62E and the other end connected to the connecting rod 70. Two suspension conductors 68 are provided so as to sandwich the signal terminal 67 in the X direction.

The tie bar 71 is provided on the opposite side of the tie bar 70 from the semiconductor element 40 so that the semiconductor element 40 is arranged between the tie bar 70 and the tie bar 71 in the Y direction. The connecting rod 71 extends in the X direction and is connected at both ends thereof to the outer peripheral frame 69. The plurality of main terminals 61C are supported by the outer peripheral frame 69 by tie bars 71. The connecting rod 71 is connected to the extension set portion 63C. The plurality of non-facing portions 65E are supported by the outer peripheral frame 69 by the connecting rods 71. The distal ends of the extension portions 63C, 63E of the main terminals 61C, 61E are connected to the outer peripheral frame 69 in the Y direction. The connection portion 62E is connected to the tie bar 70 via the suspension conductor 68, and is connected to the tie bar 71 via the extension portion 63E.

After the molding of the sealing resin body 30, unnecessary portions of the lead frame 60 such as the outer peripheral frame 69 and the tie bars 70 and 71 are removed. Thus, in the semiconductor device 20, the main terminals 61C, 61E are electrically separated from each other. Further, the plurality of signal terminals 67 are also electrically separated. The semiconductor device 20 has the main terminal 61, the signal terminal 67, and the suspension conductor 68 as the lead frame 60 without the outer frame 69 and the tie bars 70 and 71.

In the semiconductor device 10 configured as described above, the semiconductor element 40, a part of the heat sink 50, a part of the main terminal 61, and a part of the signal terminal 67 are integrally sealed by the sealing resin body 30. That is, the elements constituting 1 arm are sealed. Such a semiconductor device 20 is sometimes referred to as a 1in1 package.

Further, the heat radiation surface 501C of the heat sink 50C is substantially coplanar with the one surface 300 of the sealing resin body 30. The heat radiation surface 501E of the heat sink 50E is substantially coplanar with the back surface 301 of the sealing resin body 30. The semiconductor device 20 has a double-sided heat dissipation structure in which both heat dissipation surfaces 501C and 501E are exposed from the sealing resin body 30. Such a semiconductor device 20 can be formed by, for example, cutting the heat sink 50 together with the sealing resin body 30. The sealing resin body 30 may be molded in a state where the heat dissipation surfaces 501C and 501E are in contact with a cavity wall surface of a mold for molding the sealing resin body 30.

< summary of embodiment 1 >

Fig. 10 shows a comparative example of the semiconductor device. In the comparative example, the related elements are represented by adding r to the end of the mark added to the element of the present embodiment. As shown in fig. 10, the semiconductor device 20r of the comparative example includes a bonding wire 85r and a terminal 90 r. The signal terminal 67r is connected to a pad, not shown, of the semiconductor element 40r via a bonding wire 85 r. The terminal 90r is interposed between an unillustrated emitter electrode of the semiconductor element 40r and the heat sink 50 Er. The terminal 90r functions as a spacer that ensures the height of the bonding wire 85 r.

The heat sink 50Er is thermally and electrically connected to the emitter electrode via the terminal 90 r. The main terminal 61Er is connected to the heat sink 50 Er. The main terminal 61Er is connected to the heat sink 50Er, for example. The heat sink 50Er functions to dissipate heat generated in the semiconductor element 40 and to serve as a wiring connecting the emitter electrode and the main terminal 61 Er.

In such a structure, the heat sink 50Er is mainly opposed to the heat sink 50Cr having the same potential as the collector electrode as the portion having the same potential as the emitter electrode. The mounting surface 500Er of the heat sink 50Er faces most of the mounting surface 500Cr of the heat sink 50 Cr. As indicated by the broken-line arrows in fig. 10, the directions of the main currents are substantially reversed in the heat sinks 50Cr, 50 Er. This can cancel magnetic fluxes generated when the main current flows, thereby reducing inductance. The opposing distance Dr contributing to the reduction in inductance is the distance between the mounting surfaces 500Cr, 500 Er.

In contrast, in the present embodiment, the lead frame 60 including the main terminal 61 is provided as a member different from the heat sink 50. Main terminal 61E is disposed between heat sink 50E and semiconductor element 40, and is connected to emitter electrode 41E. Thus, as shown in fig. 6, the facing portion 64E of the main terminal 61E is closest to the portion facing the heat sink 50C and having the same potential as the emitter electrode 41E. The main terminal 61E is mainly opposed to the heat sink 50C as a portion having the same potential as the emitter electrode. The opposing distance D1 between the opposing portion 64E and the mounting surface 500C of the heat sink 50C is shorter than the opposing distance Dr described above. This can improve the effect of magnetic flux cancellation as compared with the comparative example. As a result, as shown in fig. 11, the inductance can be reduced as compared with the comparative example. Fig. 11 shows the result of magnetic field analysis (simulation) of the inductance of the opposing portion of the heat sink 50C (50Cr) and the emitter potential side.

The main terminal 61C (extension portion 63C) and the non-opposing portion 65E of the main terminal 61E are alternately arranged. The side surfaces 610C and 610E of the adjacent main terminals 61C and the non-opposing portions 65E face each other. In the main terminal 61C and the non-opposing portion 65E, the direction of the main current is substantially reversed. This can cancel magnetic fluxes generated when the main current flows, thereby reducing inductance. However, the side faces are smaller than the plate face. In contrast, the lead frame 60 has a plurality of sets of opposing side surfaces 610C, 610E. Thus, the inductance can be effectively reduced. The same type of main terminal 61C and the same type of opposing portion 65E are arranged in a plurality. This also reduces the inductance.

As described above, according to the semiconductor device 20 of the present embodiment, the inductance can be reduced.

Fig. 12 shows the effect of having a plurality of sets of opposing side surfaces 610C, 610E. Fig. 12 shows the magnetic field analysis result showing the relationship between the total number of terminal portions of the main terminal 61 and the inductance. As described above, the terminal portion is a portion of the main terminal 61 provided for connection to the outside. The lead frame 60 includes, as terminal portions, an extended portion 63C of the main terminal 61C and a non-opposing portion 65E of the main terminal 61E.

The reference is made to a structure in which two terminal portions are provided, that is, one main terminal 61C and one non-opposing portion 65E are provided. As shown in fig. 12, it is clear that if the total number of terminal portions is 3 or more, the inductance can be reduced as compared with two. In the present embodiment, since at least one of the main terminal 61C and the non-opposing portion 65E has a plurality of pieces, inductance can be reduced. Further, it is clear that the inductance can be reduced as the number of terminal portions is increased. In the present embodiment, the non-opposing portion 65E has 4 main terminals 61C and 5 main terminals 61E. This can effectively reduce the inductance.

The configuration of the main terminal 61 is not limited to the example of the non-opposing portion 65E having 4 main terminals 61C and 5 main terminals 61E. The number of main terminals 61C may be larger than the number of main terminals 61E (non-opposing portions 65E). For example, the number of main terminals 61C may be 5, and the number of non-opposing portions 65E may be 4. In this case, the main terminals 61C are disposed at both ends in the arrangement direction. The total number of terminal portions is not limited to an odd number. Or may be even. In the modification shown in fig. 13, the number of main terminals 61C is 3, and the number of non-opposing portions 65E is 3, for a total of 6.

The main terminal 61E may have a plurality of connection portions 62E. For example, if the number of the connecting portions 62E is the same as the number of the non-opposing portions 65E, the main terminals 61E have a structure independent of 1 main terminal 61C. In the modification shown in fig. 14, the main terminal 61E has 4 non-opposing portions 65E. The main terminal 61E has two connecting portions 62E, and two extending portions 63E extend from the respective connecting portions 62E. The two connection portions 62E are arranged in the X direction, and are connected to the emitter electrode 41E of the semiconductor element 40 in this arrangement state.

In contrast, in the present embodiment, the main terminal 61E has only one connection portion 62E. Since the connection portion 62E is provided in one piece, it is easy to position the connection portion with respect to the emitter electrode 41E of the semiconductor element 40. When one connection portion 62E is positioned, all of the opposing portions 64E are in a desired positional relationship with respect to the heat sink 50C. This can effectively reduce the inductance. Further, in the heat transfer path from the emitter electrode 41E to the heat sink 50E, the thermal resistance can be reduced as compared with the structure in which the connection portion 62E is divided into a plurality of portions. Further, productivity can be improved.

The connection portion 62E of the lead frame 60 may be treated to have good wettability such as Au plating. For example, by applying Au plating to the face on the semiconductor element 40 side, the semiconductor element 40 is self-aligned with respect to the lead frame 60. Thus, the manufacturing process can be simplified.

Although not shown, the signal terminal 67 may be electrically connected to the pad 42 of the semiconductor element 40 via a bonding wire. In this case, the height of the bonding wire can be realized by making the thickness of the lead frame 60 thick. However, since the opposing portion 64E is close to the mounting surface 500C of the heat sink 50C, the inductance can be reduced as compared with the above-described comparative example.

In contrast, in the present embodiment, the signal terminal 67 is connected to the pad 42 via the bonding member 83. The semiconductor device 20 has a non-bonded structure. The height of the bonding wire may not be ensured between the semiconductor element 40 and the heat sink 50E. Since the lead frame 60 is thin, the distance from the emitter electrode 41E to the heat sink 50E can be shortened as compared with the comparative example. Thereby, as shown in fig. 15, the thermal resistance can be reduced as compared with the comparative example. That is, heat dissipation can be improved.

Since the lead frame 60 is thin, the facing distance D2 between the mounting surfaces 500C and 500E shown in fig. 6 is shorter than the facing distance Dr of the reference example. Therefore, the semiconductor device 20 can be miniaturized in the Z direction. Further, since no bonding wire is required, the joint members 80, 81, 82, 83 can be collectively reflowed. Thus, the manufacturing process can be simplified. Fig. 15 shows the results of thermal analysis (simulation).

The connection position of the main terminal 61C with respect to the heat sink 50C is not particularly limited. For example, the main terminal 61C may be connected to a side surface of the heat sink 50C. In the present embodiment, the heat sink 50C is longer in the Y direction than the heat sink 50E. Thus, the heat sink 50C has the overlapping portion 51C and the non-overlapping portion 52C. The connection portion 62C of the main terminal 61C is connected to the non-overlapping portion 52C on the mounting surface 500C of the heat sink 50C. Thus, the main terminal 61C can be connected to the heat sink 50C after reflow. A connecting method without using a joining member such as solder can be adopted. The occurrence of electromigration can be suppressed.

In the present embodiment, the main terminals 61C and 61E are arranged line-symmetrically with respect to the center line CL of the semiconductor element 40 in the X direction. Thereby, the main current flows in line symmetry with respect to the center line CL. The main current flows substantially equally to the left and right of the center line CL. This can further reduce the inductance. In addition, local heat generation can be suppressed.

(embodiment 2)

This embodiment is a modification of the above embodiment. In the above embodiment, the facing portions 64E of the main terminals 61E are completely separated for each non-facing portion 65E. Alternatively, at least a part of the facing portion 64E may be integrated between the plurality of non-facing portions 65E.

Fig. 16 is a diagram showing the semiconductor device 20 of the present embodiment, and corresponds to fig. 5. Like fig. 5, the sealing resin body 30 is omitted for convenience. The main terminal 61E includes a common portion 640E and a branch portion 641E as the opposing portion 64E. The main terminal 61E has one connecting portion 62E as in the previous embodiment. The common portion 640E is connected to the connection portion 62E. The common portion 640E is provided at the root of the extended portion 63E on the side of the connection portion 62E. A portion of the extension portion 63E within a predetermined range from the connection portion 62E in the extension direction is referred to as a common portion 640E.

The common portion 640E is shared by the plurality of non-facing portions 65E. The common portion 640E extends from the connection portion 62E in the Y direction as one plate portion, and does not extend from the connection portion 62E in a plurality of portions. The common portion 640E is provided so as not to interfere with the connection of the main terminal 61C and the heat sink 50C. The connection portion 62C is connected to the non-overlapping portion 52C of the mounting surface 500C of the heat sink 50C, as in the previous embodiment. The common portion 640E is provided in a range overlapping with the heat sink 50E in a plan view viewed from the Z direction. The common portion 640E is opposed to the overlapping portion 51C of the heat sink 50C.

The branch portion 641E is a portion branched from the common portion 640E into a plurality of branches. The branch portion 641E connects the common portion 640E to the non-opposing portion 65E. The branch portions 641E are provided in the same number as the non-opposing portions 65E. The branch portion 641E extends in the Y direction integrally with the corresponding non-facing portion 65E. The branch 641E is opposed to at least the non-overlapping portion 52C of the heat sink 50C.

< summary of embodiment 2 >

In the present embodiment, the main terminal 61E has a common portion 640E as the opposing portion 64E. Therefore, the area of the main terminal 61E along the XY plane is enlarged as compared with the structure without the common portion 640E as in the previous embodiment. This can increase the area of the heat sink 50C facing the main terminal 61E, thereby further reducing the inductance. Further, the thermal resistance can be reduced. This can improve heat dissipation.

The common portion 640E may be provided in a part of the opposing portion 64E in the extending direction of the extending portion 63E. For example, the common portion 640E may be provided at a position away from the connection portion 62E. In the present embodiment, the common portion 640E is connected to the connection portion 62E. That is, the area of main terminal 61E is enlarged in the vicinity of emitter electrode 41E. This can further improve heat dissipation.

(embodiment 3)

This embodiment is a modification of the above embodiment. In the above embodiment, the thickness of the lead frame 60 is substantially constant over the entire area. Alternatively, the thickness of the lead frame 60 may be locally different. The lead frame 60 may also be used as a shaped strip.

Fig. 17 is a cross-sectional view showing the periphery of the semiconductor element 40 in the semiconductor device 20 of the present embodiment. In fig. 17, the sealing resin body 30, the main electrode 41, and the pad 42 are omitted for convenience. As shown in fig. 17, in the lead frame 60, the signal terminals 67 are thinner than the main terminals 61E. The facing distance D3 between the signal terminal 67 and the mounting surface 500C of the heat sink 50C is longer than the facing distance D1 between the main terminal 61E and the mounting surface 500C. In the lead frame 60, the signal terminals 67 are thin portions, and the portions other than the thin portions are thick portions. The plate surface of the signal terminal 67 is substantially coplanar with the main terminal 61E on the heat sink 50E side.

< summary of embodiment 3 >

In the present embodiment, the signal terminal 67 portion of the lead frame 60 is locally made thin. This ensures electrical insulation between heat sink 50C connected to collector electrode 41C and signal terminal 67. In this way, by using the lead frame 60 as the irregular strip, insulation between different potentials can be ensured.

The lead frame 60 as the shaped bar is not limited to the above example. For example, as in a modification shown in fig. 18, the connection portion 62E of the main terminal 61E in the lead frame 60 may be locally made thick. In the lead frame 60, the connection portion 62E is a thick portion, and the other portion is a thin portion. The plate surface of the connection portion 62E is substantially flush with the extension portion 63E and the like on the semiconductor element 40 side.

Thus, the facing distance D4 between the lead frame 60 and the mounting surface 500E of the heat sink 50E can be made longer than in the example shown in the previous embodiment. Therefore, when the sealing resin body 30 is molded, the resin easily flows into between the lead frame 60 and the mounting surface 500E. This can suppress molding failure of the sealing resin body 30 while exhibiting an effect of reducing inductance. In addition, the present invention can also be applied to a structure in which the signal terminal 67 is connected to the pad 42 via a bonding wire.

The plate surface of the connection portion 62E may be substantially flush with the extension portion 63E and the like on the heat sink 50E side. In this case, the main terminal 61E is located farther from the mounting surface 500C, but the inductance can be reduced as compared with the comparative example described above. Further, the resin easily flows into between the lead frame 60 and the mounting surface 500C, and molding defects can be suppressed.

(other embodiments)

An example in which the semiconductor device 20 is applied to the inverter 5 is shown, but the present invention is not limited thereto. For example, the present invention can also be applied to a converter. The present invention can also be applied to both the inverter 5 and the converter.

The example in which the IGBT6i and the FWD6d are formed in the semiconductor element 40 is shown, but the present invention is not limited thereto. It is also possible to make the FWD6d a separate chip.

The example of the IGBT6i is shown as the switching element, but the switching element is not limited to this. For example, MOSFETs may also be used.

The heat dissipation surfaces 501C and 501E are exposed from the sealing resin body 30, but the present invention is not limited thereto. At least one of the heat dissipation surfaces 501C and 501E may be covered with the sealing resin body 30. The sealing resin body 30 may be covered with an insulating member, not shown, other than the insulating member.

Although not shown, a through hole may be provided in the lead frame 60 at a portion facing the heat sink 50. This can suppress molding defects. The main terminal 61 may be provided with a through hole. For example, the common portion 640E may be provided. The signal terminal 67 may be provided with a through hole. The suspension conductor 68 may be provided with a through hole.

While the embodiments, structures, and aspects of the semiconductor device according to the aspect of the present invention have been described above, the embodiments, structures, and aspects of the present invention are not limited to the above-described embodiments, structures, and aspects. For example, embodiments, structures, and aspects obtained by appropriately combining the disclosed technical features with different embodiments, structures, and aspects are also included in the scope of the embodiments, structures, and aspects of the present invention.