JP6939679B2 - Semiconductor device - Google Patents

Description

The disclosure herein relates to semiconductor devices.

Patent Document 1 describes a semiconductor element having main electrodes on both sides, a heat radiating portion (heat sink) arranged so as to sandwich the semiconductor element, at least a part of the radiating portion, and a sealing resin body for integrally sealing the semiconductor element. A semiconductor device comprising the above is disclosed.

The semiconductor device has a first heat radiating unit connected to the main electrode on the one side and a second heat radiating part connected to the main electrode on the back surface side as the heat radiating unit. An uneven oxide film is formed on the mounting surface of each heat radiating portion so as to surround the connection portion with the main electrode. The surface of the concavo-convex oxide film is continuously concavo-convex, and the adhesion to the sealing resin body can be improved.

Japanese Unexamined Patent Publication No. 2016-197706

The concave-convex oxide film is an oxide film of the same metal as the main component metal of the metal thin film, which is formed on the metal thin film by irradiating the metal thin film with laser light. Such an uneven oxide film can be formed by irradiating a metal thin film with a laser beam of pulse oscillation at a low energy density (100 J / cm ^{2 or less).} Since the laser beam is used, it can be formed only in a desired portion as compared with a configuration in which a polyamide or the like is formed in order to improve the adhesion to the sealing resin body. The uneven oxide film is formed on the mounting surface of each heat radiating portion in the semiconductor device.

The semiconductor device having the above configuration is laminated alternately with the cooler, for example, and is held between the coolers. The semiconductor device is sandwiched between the coolers in the stacking direction, and stress acts on the semiconductor device in the state of being attached to the cooler. If only the first heat radiation portion is provided with an extension portion that is connected to a side surface in one direction orthogonal to the stacking direction and extends in one direction from this side surface and protrudes from the sealing resin body, the extension portion is provided. The above-mentioned stress is concentrated on the boundary portion between the second heat radiating portion and the sealing resin body which are not connected to each other. Specifically, stress is concentrated on the one-way side surface of the second heat radiating portion, which is the boundary portion between the surface on the extending portion side and the sealing resin body. Due to such stress concentration, cracks may occur in the sealing resin body.

The present disclosure has been made in view of such a problem, and an object of the present disclosure is to suppress the occurrence of cracks in the sealing resin body in a semiconductor device in which stress acts due to lamination with a cooler.

The present disclosure employs the following technical means to achieve the above objectives. The reference numerals in parentheses indicate the correspondence with the specific means described in the embodiment described later as one embodiment, and do not limit the technical scope.

The semiconductor device, which is one of the disclosures, is
A semiconductor device that is laminated with the cooler (50) and is sandwiched and held by the cooler in the stacking direction.
At least one semiconductor element (11H, 11L) having a main electrode (11c, 11e) formed on one surface in the stacking direction and the back surface opposite to one surface, respectively.
It is a heat radiating part arranged so as to sandwich the semiconductor element in the stacking direction, and is electrically connected to the first heat radiating part (14H, 14L) electrically connected to the main electrode on the one side and the main electrode on the back side. With the connected second heat dissipation part (18H, 18L),
A sealing resin body (13) that integrally seals at least a part of the first heat radiating part, at least a part of the second heat radiating part, and a semiconductor element.
The first heat dissipation part of the heat dissipation part, which is connected to the first side surface (14c) in one direction orthogonal to the stacking direction, extends in one direction from the first side surface, and extends from the sealing resin body. Part (22p, 23) and
It is a film (34) formed on the surface of the heat radiating portion and in the sealed portion by the sealing resin body, and is formed on the metal thin film (35) and the metal thin film, and is the same as the metal as the main component of the metal thin film. An uneven oxide film (30), which is a metal oxide film and whose surface is continuously uneven,
With
Uneven oxide film, the mounting surface roughened portion formed so as to surround the connecting portion between the main electrode in the mounting surface of the heat radiation section (31), of the side surface of the second heat radiating unit, corresponding to the first side surface It has a side surface roughened portion (32) formed only on the second side surface (18d, 18e).

According to this semiconductor device, as a roughened portion by the uneven oxide film, a side roughened portion is provided in addition to the mounted surface roughened portion. The side surface roughened portion is formed on the second side surface corresponding to the first side surface in which the extending portions are connected in the second heat radiating portion. By providing the side surface roughened portion, in the laminated structure with the cooler, the adhesion of the boundary portion between the second side surface where stress is concentrated and the sealing resin body is higher than before. Therefore, it is possible to suppress the occurrence of cracks in the sealing resin body in the semiconductor device in which stress acts due to the lamination with the cooler while locally providing the portion having high adhesion to the sealing resin body. ..

It is a figure which shows the schematic structure of the power conversion apparatus to which the semiconductor apparatus of 1st Embodiment is applied. It is a perspective view which shows the semiconductor device. It is a top view which shows the semiconductor device. It is sectional drawing which follows the IV-IV line of FIG. It is sectional drawing which follows the VV line of FIG. It is a perspective view which shows the lead frame. It is a perspective view which shows the state which mounted the semiconductor element and the terminal. It is a top view which shows the state which mounted the semiconductor element and the terminal. It is an enlarged view of the area IX of FIG. It is a perspective view which shows the state which mounted the 2nd heat sink. It is a perspective view which shows the state which formed the sealing resin body. It is a perspective view which shows the state after cutting. It is a figure which shows the laminated structure with a cooler. It is a perspective view which shows the detailed structure of the 2nd heat sink. It is a perspective view of the 2nd heat sink seen from another angle. It is sectional drawing which follows the XVI-XVI line of FIG. It is a plan view which shows a reference example, and corresponds to FIG. It is a perspective view which shows the side surface roughened part, and corresponds to FIG. It is a perspective view which shows the side surface roughened part in the semiconductor device of 2nd Embodiment, and corresponds to FIG. It is a perspective view which shows the side surface roughened part in the semiconductor device of 3rd Embodiment, and corresponds to FIG. It is a top view which shows another example.

A plurality of embodiments will be described with reference to the drawings. In a plurality of embodiments, the functionally and / or structurally corresponding parts are assigned the same reference numerals. In the following, the thickness direction of the semiconductor element (IGBT) is shown as the Z direction and orthogonal to the Z direction, and the arrangement direction of the semiconductor elements is shown as the X direction. Further, a direction orthogonal to both the Z direction and the X direction is indicated as the Y direction. Unless otherwise specified, the shape when viewed in XY plane (shape along the XY plane) is defined as a plane shape. The XY plane view can also be said to be a projection view in the Z direction. The Z direction corresponds to the stacking direction, and the Y direction corresponds to one direction or the first direction. The X direction corresponds to the second direction.

(First Embodiment)
In the following, H at the end of the reference numeral indicates an element on the upper arm side of the upper and lower arms, and L at the end indicates an element on the lower arm side. H and L are added to the end of some of the elements to clarify the upper arm and the lower arm, and the other part has a common code for the upper arm and the lower arm.

(Outline configuration of power converter)
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 is configured to convert a DC voltage supplied from a DC power supply 2 mounted on a vehicle into a three-phase AC and output it to a three-phase AC motor 3. The motor 3 functions as a traveling drive source for the vehicle. The power conversion device 1 can also convert the electric power generated by the motor 3 into direct current and charge the direct current power supply 2. In this way, the power conversion device 1 is capable of bidirectional power conversion.

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

The inverter 5 includes six arms. The inverter 5 is composed of upper and lower arms for three phases. The upper and lower arms of each phase are formed by connecting two arms in series between a positive electrode side line 6 which is a power supply line on the positive electrode side and a negative electrode side line 7 which is a power supply line on the negative electrode side. The positive electrode side line 6 is also referred to as a high potential power supply line, and the negative electrode side line 7 is also referred to as a low potential power supply line. In the upper and lower arms of each phase, the connection point between the upper arm and the lower arm is connected to the output line 8 to the motor 3.

In this embodiment, an insulated gate bipolar transistor (hereinafter referred to as an IGBT) is used as the semiconductor element constituting each arm. The semiconductor device 10 includes two IGBTs 11H and 11L connected in series. FWD12H and 12L, which are diodes for reflux, are connected in antiparallel to each of the IGBTs 11H and 11L. As described above, the upper and lower arms for one phase are configured to have two IGBTs 11H and 11L. Reference numeral 11g shown in FIG. 1 is a gate electrode of IGBT 11H, 11L. As described above, the semiconductor element has a gate electrode of 11 g.

Further, the n-channel type is adopted as the IGBTs 11H and 11L. The collector electrode 11c of the IGBT 11H constituting the upper arm is electrically connected to the positive electrode side line 6. The emitter electrode 11e of the IGBT 11L constituting the lower arm is electrically connected to the negative electrode side line 7. The emitter electrode 11e of the IGBT 11H on the upper arm side and the collector electrode 11c of the IGBT 11L on the lower arm side are connected to each other.

In addition to the smoothing capacitor 4 and the inverter 5 described above, the power conversion device 1 is a gate drive that controls the operation of a boost converter that boosts the DC voltage supplied from the DC power supply 2, the inverter 5, and the semiconductor elements that make up the boost converter. A circuit or the like may be provided.

(Outline configuration of semiconductor device)
As shown in FIGS. 2 to 12, in the semiconductor device 10, the IGBT 11H, 11L, the sealing resin body 13, the first heat sink 14H, 14L, the terminal 16, the second heat sink 18H, 18L, the joint portion 20, the power supply terminal 22, It includes an output terminal 23 and a signal terminal 24. In FIGS. 4 to 11, for convenience, the uneven oxide film 30 (roughened portion) described later is omitted.

The IGBTs 11H and 11L as semiconductor elements are configured on a semiconductor substrate such as Si, SiC, or GaN. In the present embodiment, as described above, the IGBTs 11H and 11L are both n-channel type. FWD12H and 12L are also integrally formed on the IGBTs 11H and 11L. Specifically, FWD12H is formed on the IGBT 11H, and FWD12L is formed on the IGBT 11L. As described above, RC (Reverse Conducting) -IGBT is adopted as the IGBTs 11H and 11L. The IGBT 11H corresponds to the upper arm element, and the IGBT 11L corresponds to the lower arm element.

The IGBTs 11H and 11L have a vertical structure so that a current flows in the Z direction. The gate electrodes 11g described above are also formed on the IGBTs 11H and 11L, respectively. The gate electrode 11g has a trench structure. As shown in FIGS. 4 and 5, in the thickness direction of the IGBTs 11H and 11L, that is, in the Z direction, the collector electrodes 11c are formed on one surface of the IGBTs 11H and 11L, and the emitter electrodes 11e are formed on the back surfaces opposite to the one surface. There is. The collector electrode 11c also serves as the cathode electrode of the FWD 12H, 12L, and the emitter electrode 11e also serves as the anode electrode of the FWD 12H, 12L. The collector electrode 11c corresponds to the main electrode on the one side, and the emitter electrode 11e corresponds to the main electrode on the back side.

The IGBTs 11H and 11L have substantially the same planar shape, more specifically, a substantially rectangular shape, and have approximately the same size and thickness as each other. The IGBTs 11H and 11L have the same configuration as each other. The IGBTs 11H and 11L are arranged so that the collector electrodes 11c of each other are on the same side in the Z direction and the emitter electrodes 11e of each other are on the same side in the Z direction. The IGBTs 11H and 11L are located at substantially the same height in the Z direction and are arranged side by side in the X direction.

As shown in FIG. 9, a pad 11p, which is an electrode for signals, is formed on the back surface of the IGBTs 11H and 11L, that is, on the surface on which the emitter electrode is formed. The pad 11p is formed at a position different from that of the emitter electrode 11e. The pad 11p is electrically separated from the emitter electrode 11e. The pad 11p is formed at an end portion opposite to the forming region of the emitter electrode 11e in the Y direction.

In this embodiment, each IGBT 11H, 11L has six pads 11p, respectively. Specifically, the six pads 11p are for the gate electrode 11g, for the dummy gate electrode, for the Kelvin emitter that detects the potential of the emitter electrode 11e, for the current sense, and for the temperature sensor (temperature sensitive diode) that detects the temperature of the IGBTs 11H and 11L. It has an anode potential and a cathode potential. The six pads are collectively formed on one end side in the Y direction and arranged side by side in the X direction in the IGBTs 11H and 11L having a substantially rectangular plane. The dummy gate electrode is a gate electrode that does not contribute to the generation of the inversion layer (channel).

The sealing resin body 13 seals the IGBTs 11H and 11L. The sealing resin body 13 is made of, for example, an epoxy resin. The sealing resin body 13 is molded by, for example, a transfer molding method. The sealing resin body 13 has a side surface 13a orthogonal to the Z direction, a back surface 13b opposite to the one surface 13a, and a side surface connecting the one surface 13a and the back surface 13b. The front surface 13a and the back surface 13b are, for example, flat surfaces.

The first heat sinks 14H and 14L have a function of dissipating the heat of the corresponding IGBTs 11H and 11L to the outside of the semiconductor device 10. The first heat sinks 14H and 14L also function as wiring. Therefore, it is formed by using at least a metal material in order to secure thermal conductivity and electrical conductivity. In the present embodiment, the first heat sinks 14H and 14L are provided so as to include the corresponding IGBTs 11H and 11L in the projection view from the Z direction. The first heat sinks 14H and 14L are arranged on one surface 13a side of the sealing resin body 13 with respect to the corresponding IGBTs 11H and 11L.

The first heat sinks 14H and 14L are connected to the collector electrodes 11c of the corresponding IGBTs 11H and 11L via the solder 15. The first heat sinks 14H and 14L correspond to the first heat radiating portion. Most of the first heat sinks 14H and 14L are covered with the sealing resin body 13. Of the surfaces of the first heat sinks 14H and 14L, the solder 15 is connected to the mounting surface 14a, and the heat radiating surface 14b opposite to the mounting surface 14a is exposed from the sealing resin body 13. The heat radiating surface 14b is substantially flush with the surface 13a. Of the surfaces of the first heat sinks 14H and 14L, a part of the mounting surface 14a and a portion other than the heat radiating surface 14b are covered with the sealing resin body 13.

Specifically, the collector electrode 11c of the IGBT 11H is connected to the mounting surface 14a of the first heat sink 14H via the solder 15. The collector electrode 11c of the IGBT 11L is connected to the mounting surface 14a of the first heat sink 14L via the solder 15. The first heat sinks 14H and 14L are arranged side by side in the X direction and are arranged at substantially the same position in the Z direction. The heat radiating surfaces 14b of the first heat sinks 14H and 14L are exposed from one surface 13a of the sealing resin body 13 and are aligned with each other in the X direction.

The terminal 16 is interposed between the corresponding IGBTs 11H and 11L and the second heat sinks 18H and 18L. Since the terminal 16 is located in the middle of the heat conduction and electric conduction paths between the IGBTs 11H and 11L and the second heat sinks 18H and 18L, it is formed by using at least a metal material in order to secure the heat conduction and the electric conductivity. There is. The terminal 16 is arranged to face the emitter electrode 11e and is connected to the emitter electrode 11e via a solder 17. Terminals 16 are provided for each IGBT 11H and 11L.

Like the first heat sinks 14H and 14L, the second heat sinks 18H and 18L also function to dissipate the heat of the corresponding IGBTs 11H and 11L to the outside of the semiconductor device 10. The second heat sinks 18H and 18L also function as wiring. In the present embodiment, the second heat sinks 18H and 18L are provided so as to include the corresponding IGBTs 11H and 11L in the projection view from the Z direction. The second heat sinks 18H and 18L are arranged on the back surface 13b side of the sealing resin body 13 with respect to the corresponding IGBTs 11H and 11L in the Z direction.

The second heat sinks 18H and 18L are electrically connected to the emitter electrodes 11e of the corresponding IGBTs 11H and 11L. Specifically, the second heat sinks 18H and 18L are electrically connected to the corresponding emitter electrodes 11e via the solder 17, the terminal 16, and the solder 19. The second heat sinks 18H and 18L correspond to the second heat radiating portion. Most of the second heat sinks 18H and 18L are covered with the sealing resin body 13. Of the surfaces of the second heat sinks 18H and 18L, the solder 19 is connected to the mounting surface 18a, and the heat radiating surface 18b opposite to the mounting surface 18a is exposed from the sealing resin body 13. The heat radiating surface 18b is substantially flush with the back surface 13b. Of the surfaces of the second heat sinks 18H and 18L, a part of the mounting surface 18a and a portion other than the heat radiating surface 18b are covered with the sealing resin body 13.

Specifically, the terminal 16 corresponding to the IGBT 11H is connected to the mounting surface 18a of the second heat sink 18H via the solder 19. A terminal 16 corresponding to the IGBT 11L is connected to the mounting surface 18a of the second heat sink 18L via a solder 19. A groove 18c for absorbing the overflowing solder 19 is formed on each mounting surface 18a. The groove 18c is formed in an annular shape so as to surround the emitter electrode 11e, that is, the terminal 16 in the projection view from the Z direction.

The second heat sinks 18H and 18L are arranged side by side in the X direction and are arranged at substantially the same positions in the Z direction. The heat radiating surfaces 18b of the second heat sinks 18H and 18L are exposed from the back surface 13b of the sealing resin body 13 and are aligned with each other in the X direction. In the present embodiment, the second heat sinks 18H and 18L are common members, and the arrangement of the second heat sink 18H and the second heat sink 18L is quadratic symmetrical with the Z axis as the rotation axis. The second heat sinks 18H and 18L have side surfaces 18d and 18e in the Y direction. In the second heat sink 18H, the side surface 18d corresponds to the side surface 14c, and in the second heat sink 18L, the side surface 18e corresponds to the side surface 14c. Therefore, the side surface 18d of the second heat sink 18H and the side surface 18e of the second heat sink 18L correspond to the second side surface. The side surface 18d of the second heat sink 18H and the side surface 18e of the second heat sink 18L are surfaces on the same side as the side surface 14c in the Y direction, and the members extending in the Y direction are not connected.

The joint portion 20 has a first joint portion 20a, a second joint portion 20b, and a third joint portion 20c. The first joint portion 20a and the third joint portion 20c electrically connect the second heat sink 18H on the upper arm side and the first heat sink 14L on the lower arm side. As shown in FIGS. 5 and 10, the second joint portion 20b electrically connects the second heat sink 18L on the lower arm side and the negative electrode terminal 22n.

In the present embodiment, the first joint portion 20a is integrally provided with the second heat sink 18H by processing the same metal plate. Further, the second joint portion 20b is integrally provided with the second heat sink 18L by processing the same metal plate. The second heat sink 18H including the first joint portion 20a and the second heat sink 18L including the second joint portion 20b are common members, and in the semiconductor device 10, these arrangements are twice symmetrical with the Z axis as the rotation axis. It has become.

The first joint portion 20a is provided thinner than the second heat sink 18H so as to be covered with the sealing resin body 13. The first joint portion 20a is connected to the second heat sink 18H so as to be substantially flush with the mounting surface 18a of the second heat sink 18H. The first joint portion 20a has a thin plate shape and extends in the X direction from the side surface of the second heat sink 18H on the second heat sink 18L side. In the member having the first joint portion 20a and the second heat sink 18H, the second heat sink 18H corresponds to a thick portion that is connected to the emitter electrode 11e and performs a heat dissipation function, and the first joint portion 20a is from the thick portion. Is also thinned and corresponds to a thin-walled part that fulfills an electrical relay function. The thin-walled first joint portion 20a extends in the X direction from the side surface of the thick-walled second heat sink 18H, and does not extend in the Y direction. In the first joint portion 20a, the third joint portion 20c is connected to the surface of the second heat sink 18H that is connected to the mounting surface 18a via the solder 21.

The second joint portion 20b is also provided thinner than the second heat sink 18L so as to be covered with the sealing resin body 13. The second joint portion 20b is connected to the second heat sink 18L so as to be substantially flush with the mounting surface 18a of the second heat sink 18L. The second joint portion 20b has a thin plate shape and extends in the X direction from the side surface of the second heat sink 18L on the side of the second heat sink 18L.

In the member having the second joint portion 20b and the second heat sink 18L, the second heat sink 18L corresponds to a thick portion that is connected to the emitter electrode 11e and performs a heat dissipation function, and the second joint portion 20b is from the thick portion. Is also thinned and corresponds to a thin-walled part that fulfills an electrical relay function. The thin-walled second joint portion 20b extends in the X direction from the side surface of the thick-walled second heat sink 18L, and does not extend in the Y direction. In the second joint portion 20b, the negative electrode terminal 22n is connected to the surface of the second heat sink 18L that is connected to the mounting surface 18a via the solder 21.

A groove 20d for absorbing the overflowing solder 21 is formed on a surface connected to the mounting surface 18a of each of the first joint portion 20a and the second joint portion 20b. The groove 20d is formed in an annular shape. Hereinafter, the first joint portion 20a and the second joint portion 20b are also simply referred to as joint portions 20a and 20b.

In this embodiment, solder containing Ni balls is used as the solders 15, 17, 19, and 21. The Ni ball may have a diameter that can secure a solder thickness that can be inspected by an ultrasonic flaw detector (SAT: Scanning Acoustic Tomograph), for example, 40 μm or more. As a result, for example, voids can be detected for any of the solders 15, 17, 19, and 21.

The third joint portion 20c is also provided integrally with the first heat sink 14L by processing the same metal plate. The third joint portion 20c is provided thinner than the first heat sink 14L so as to be covered with the sealing resin body 13. The third joint portion 20c is substantially flush with the mounting surface 14a of the first heat sink 14L. The third joint portion 20c extends from the side surface of the first heat sink 14L on the side of the first heat sink 14H toward the second heat sink 18H.

The third joint portion 20c extends in the X direction in a plan view from the Z direction. In the present embodiment, as shown in FIG. 4, the third joint portion 20c has two bent portions. The tip portion of the third joint portion 20c overlaps with the first joint portion 20a in the projection view from the Z direction. Then, the third joint portion 20c and the first joint portion 20a are connected via the solder 21. The third joint portion 20c is provided so as to be side by side with the second joint portion 20b in the Y direction.

The first joint portion 20a may be a separate member from the second heat sink 18H, and may be connected to the second heat sink 18H so as to be connected to the second heat sink 18H. The second joint portion 20b may be a separate member from the second heat sink 18L, and may be connected to the second heat sink 18L so as to be connected to the second heat sink 18L. Further, the third joint portion 20c may be a separate member from the first heat sink 14L and may be connected to the first heat sink 14L so as to be connected to the first heat sink 14L. The upper arm and the lower arm can be electrically connected by only one of the first joint portion 20a and the third joint portion 20c.

The power supply terminal 22 has a positive electrode terminal 22p and a negative electrode terminal 22n. The positive electrode terminal 22p is electrically connected to the terminal on the positive electrode side of the smoothing capacitor 4. The positive electrode terminal 22p is electrically connected to the positive electrode side line 6. The positive electrode terminal 22p is a main terminal through which a main current flows. The positive electrode terminal 22p is also referred to as a high potential power supply terminal or a P terminal. The positive electrode terminal 22p is connected to the first heat sink 14H, and extends in the Y direction from the side surface 14c of the side surface of the first heat sink 14H, which is opposite to the surface on the signal terminal 24 side in the Y direction. The positive electrode terminal 22p corresponds to the extension portion or the first main terminal, and the side surface 14c corresponds to the first side surface. In the present embodiment, the positive electrode terminal 22p is integrally provided with the first heat sink 14H by processing the same metal plate. The positive electrode terminal 22p is connected to one end of the first heat sink 14H in the Y direction. The positive electrode terminal 22p extends in the Y direction and projects outward from the side surface 13c of the sealing resin body 13 as shown in FIG.

A deformed strip is used as the metal plate constituting the first heat sink 14H and the positive electrode terminal 22p, and the positive electrode terminal 22p has a thin plate shape. In the member having the positive electrode terminal 22p and the first heat sink 14H, the first heat sink 14H corresponds to a thick portion which is connected to the collector electrode 11c and performs a heat dissipation function, and the positive electrode terminal 22p is made thinner than the thick portion. It corresponds to a thin-walled part that functions as an electrical relay. The positive electrode terminal 22p, which is a thin portion, extends in the Y direction from the side surface 14c of the first heat sink 14H, which is a thick portion, and protrudes from the side surface 13c of the sealing resin body 13.

The negative electrode terminal 22n is electrically connected to the terminal on the negative electrode side of the smoothing capacitor 4. The negative electrode terminal 22n is electrically connected to the negative electrode side line 7. The negative electrode terminal 22n is a main terminal through which a main current flows. The negative electrode terminal 22n is also referred to as a low potential power supply terminal or an N terminal. A part of the negative electrode terminal 22n is arranged so as to overlap the third joint portion 20c in the projection view from the Z direction. The negative electrode terminal 22n is arranged at a position closer to the IGBT 11L than the third joint portion 20c in the Z direction. The negative electrode terminal 22n and the third joint portion 20c are also connected via the solder 21.

The negative electrode terminal 22n extends in the Y direction and projects outward from the same side surface 13c as the positive electrode terminal 22p. As shown in FIGS. 5 and 6, the thickness of the connection portion of the negative electrode terminal 22n with the second joint portion 20b is the thickness of the other portion, for example, the thickness of the portion protruding outward from the sealing resin body 13. Is made thicker than.

The output terminal 23 is electrically connected to the connection point of the upper and lower arms. The output terminal 23 is a main terminal through which a main current flows. The output terminal 23 is electrically connected to a coil (stator winding) of the corresponding phase of the motor 3. The output terminal 23 is also referred to as an AC terminal or an O terminal. The output terminal 23 is connected to the first heat sink 14L, and is the same as the positive electrode terminal 22p in the Y direction from the side surface 14c of the side surface of the first heat sink 14L opposite to the surface on the signal terminal 24 side in the Y direction. It is extended to the side. The output terminal 23 corresponds to the extension portion or the second main terminal, and the side surface 14c of the first heat sink 14L corresponds to the first side surface.

In the present embodiment, the output terminal 23 is integrally provided with the first heat sink 14L by processing the same metal plate. The output terminal 23 is connected to one end of the first heat sink 14L in the Y direction. The output terminal 23 extends in the Y direction and projects outward from the same side surface 13c as the positive electrode terminal 22p and the negative electrode terminal 22n.

A deformed strip is adopted as the metal plate constituting the first heat sink 14L and the output terminal 23, and the output terminal 23 has a thin plate shape. In the member having the output terminal 23 and the first heat sink 14L, the first heat sink 14L corresponds to a thick portion which is connected to the collector electrode 11c and performs a heat dissipation function, and the output terminal 23 is thinner than the thick portion. It corresponds to a thin-walled part that functions as an electrical relay. The output terminal 23, which is a thin-walled portion, extends in the Y direction from the side surface 14c of the first heat sink 14L, which is a thick-walled portion, and protrudes from the side surface 13c of the sealing resin body 13.

The protruding portions of the positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23 from the sealing resin body 13 are arranged at substantially the same positions in the Z direction. Further, in the X direction, the positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23 are arranged side by side in this order. In this way, the negative electrode terminal 22n is arranged next to the positive electrode terminal 22p.

The positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23 are formed in a substantially flat plate shape at least in a portion protruding from the sealing resin body 13, and the thicknesses in the Z direction are substantially equal to each other. Therefore, the thicknesses of the protruding portions of the positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23 are substantially equal to each other. Further, the widths of the protruding portions of the positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23 are substantially equal to each other. Here, the width is a length orthogonal to both the Y direction, which is the projecting direction from the side surface 13c, and the Z direction, which is the plate thickness direction, that is, the length in the X direction.

Further, the protruding length of the positive electrode terminal 22p is shorter than the protruding length of the negative electrode terminal 22n. Here, the protruding length is a length extending to the outside with the side surface 13c of the sealing resin body 13 as a reference for the position. In the present embodiment, the protruding length of the output terminal 23 is longer than the protruding length of the negative electrode terminal 22n. That is, the protrusion length is the shortest at the positive electrode terminal 22p and the longest at the output terminal 23. The protruding length of the negative electrode terminal 22n is set to an intermediate length.

The positive electrode terminal 22p may be a separate member from the first heat sink 14H and may be connected to the first heat sink 14H so as to be connected to the first heat sink 14H. The negative electrode terminal 22n may be made of the same metal plate as the third joint portion 20c and the second heat sink 18L. The output terminal 23 may be a separate member from the first heat sink 14L and may be connected to the first heat sink 14L so as to be connected to the first heat sink 14L.

Bus bars (not shown) are connected to the power supply terminal 22 and the output terminal 23 in a laminated state with a cooler described later. The bus bar constitutes a positive electrode side line 6, a negative electrode side line 7, and an output line 8. The bus bar is connected to the corresponding power supply terminal 22 and output terminal 23 by laser welding, for example.

As shown in FIGS. 7 to 9, the signal terminal 24 is electrically connected to the pads 11p of the corresponding IGBTs 11H and 11L via the bonding wire 25. In this embodiment, the aluminum-based bonding wire 25 is adopted. The signal terminal 24 extends in the Y direction, and as shown in FIG. 3, the signal terminal 24 projects outward from the side surface 13d opposite to the side surface 13c in the sealing resin body 13.

The semiconductor device 10 has five signal terminals 24 for the IGBT 11H and five signal terminals 24 for the IGBT 11L. Of the five signal terminals 24, one signal terminal 24a has a wider area in the X direction to which the bonding wire 25 is connected than the remaining signal terminals 24b. A pad 11p for a Kelvin emitter that detects the potential of the emitter electrode 11e and a pad 11p for a dummy gate electrode are connected to the signal terminal 24a via a bonding wire 25, respectively. As a result, the dummy gate electrode is fixed to the emitter potential. The pads 11p for the gate electrode 11g, the current sense, the anode potential of the temperature sensor, and the cathode potential are connected to different signal terminals 24b.

As shown in FIG. 6 and the like, in the present embodiment, the first heat sink 14H, 14L, the third joint portion 20c, the positive electrode terminal 22p, the negative electrode terminal 22n, the output terminal 23, and the signal terminal 24 are the same metal plate. It is composed of a lead frame 26. In addition to the above, the lead frame 26 has an outer frame 26a, a hanging lead 26b, a tie bar 26c, and the like. In the lead frame 26, a part of the first heat sinks 14H and 14L and the negative electrode terminal 22n is a thick portion, and the other portion is a thin portion thinner than the thick portion.

In the Y direction, the first heat sink 14H is connected to the outer frame 26a via a positive electrode terminal 22p extending from the side surface 14c. The first heat sink 14L is also connected to the outer frame 26a via an output terminal 23 extending from the side surface 14c. Further, a suspension lead 26b is connected to the side surface 14d of the first heat sinks 14H and 14L opposite to the side surface 14c. The suspension lead 26b extends in the Y direction from the side surface 14d and is connected to the outer frame 26a.

One ends of the positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23, which are the main terminals, are connected to the outer frame 26a in the Y direction. Further, they are connected to each other by a tie bar 26c extending in the X direction. The signal terminal 24 is connected to the outer frame 26a and the suspension lead 26b by the tie bar 26c. In the signal terminal 24, the end opposite to the end to which the bonding wire 25 is connected is not connected to the outer frame 26a and is free.

In the semiconductor device 10 configured as described above, the sealing resin body 13 causes the IGBT 11H, 11L, a part of each of the first heat sinks 14H, 14L, the terminal 16, a part of each of the second heat sinks 18H, 18L, and the power supply terminal. A part of each of the 22s, a part of the output terminal 23, and a part of the signal terminal 24 are integrally sealed. In the semiconductor device 10, the sealing resin body 13 seals the two IGBTs 11H and 11L that form the upper and lower arms for one phase. Therefore, the semiconductor device 10 is also referred to as a 2in1 package.

The heat radiating surfaces 14b of the first heat sinks 14H and 14L are located in the same surface and are substantially flush with one surface 13a of the sealing resin body 13. Similarly, the heat radiating surfaces 18b of the second heat sinks 18H and 18L are located on the same surface and are substantially flush with the back surface 13b of the sealing resin body 13. As described above, the semiconductor device 10 has a double-sided heat radiating structure in which both the heat radiating surfaces 14b and 18b are exposed from the sealing resin body 13.

(Manufacturing method of semiconductor device 10)
The outline of the manufacturing method will be described. First, each element constituting the semiconductor device 10 is prepared. For example, the lead frame 26 shown in FIG. 6 is prepared. Further, the IGBTs 11H and 11L, the terminal 16, the second heat sink 18H including the first joint portion 20a, and the second heat sink 18L including the second joint portion 20b are prepared. The second heat sinks 18H and 18L are common members as described above.

Next, the corresponding IGBTs 11H, 11L are arranged on the mounting surface 14a of the first heat sinks 14H, 14L in the lead frame 26 via the solder 15. At that time, the IGBTs 11H and 11L are arranged so that the collector electrode 11c faces the mounting surface 14a. Next, for example, the terminal 16 in which the solders 17 and 19 are previously arranged on both sides as the receiving solder is arranged so that the solder 17 is on the IGBT 11H, 11L side. The solder 19 is arranged in an amount capable of absorbing the height variation in the semiconductor device 10. Further, the solder 21 is arranged on the third joint portion 20c and the negative electrode terminal 22n.

Then, in this laminated state, the 1st reflow of the solder is performed. As a result, the collector electrodes 11c of the IGBTs 11H and 11L and the corresponding first heat sinks 14H and 14L are connected via the solder 15. Further, the emitter electrodes 11e of the IGBTs 11H and 11L and the corresponding terminals 16 are connected via the solder 17. That is, it is possible to obtain a connector in which the lead frame 26, the IGBT 11H, 11L, and the terminal 16 are integrated. After reflow, the pads 11p of the IGBTs 11H and 11L and the signal terminals 24 are connected by the bonding wire 25. 7, 8 and 9 show the bonded body after bonding.

Next, the second heat sinks 18H and 18L are arranged on a pedestal (not shown) so that the mounting surface 18a faces up. Then, the connector is arranged on the second heat sinks 18H and 18L so that the terminal 16 faces the second heat sinks 18H and 18L, and the 2nd reflow of the solder is performed. In the 2nd reflow, a load is applied from the first heat sinks 14H and 14L side so that the height of the semiconductor device 10 becomes a predetermined height. Specifically, a spacer (not shown) is placed between the first heat sinks 14H, 14L and the pedestal, and the spacer is brought into contact with both the first heat sinks 14H, 14L and the pedestal. In this way, the height of the semiconductor device 10 is set to a predetermined height. FIG. 10 shows the state after the 2nd reflow.

Next, the sealing resin body 13 is molded by the transfer molding method. In the present embodiment, the sealing resin body 13 is molded so that the first heat sinks 14H and 14L and the second heat sinks 18H and 18L are completely covered. FIG. 11 shows the state after molding.

Next, the heat-dissipating surface 14b of the first heat sinks 14H and 14L is exposed by cutting the molded sealing resin body 13 together with a part of the first heat sinks 14H and 14L. As a result, the heat radiating surface 14b becomes substantially flush with the surface 13a. Similarly, the heat-dissipating surface 18b of the second heat sinks 18H and 18L is exposed by cutting the sealing resin body 13 together with a part of the second heat sinks 18H and 18L. As a result, the heat radiating surface 18b is substantially flush with the back surface 13b.

FIG. 12 shows the state after cutting. The sealing resin body 13 may be molded in a state where the heat radiating surfaces 14b and 18b are pressed against the cavity wall surface of the molding die and are in close contact with each other. In this case, the heat radiating surfaces 14b and 18b are exposed from the sealing resin body 13 when the sealing resin body 13 is molded. Therefore, cutting after molding becomes unnecessary.

Next, unnecessary parts of the lead frame 26 such as the outer frame 26a and the tie bar 26c are removed. Thereby, the semiconductor device 10 can be obtained.

(Laminate structure with cooler)
As shown in FIG. 13, the semiconductor device 10 is alternately laminated with the cooler 50 to form a power module together with the cooler 50. The cooler 50 has a refrigerant flowing inside and is arranged on both sides of each semiconductor device 10 in the Z direction to cool the semiconductor device 10 from both sides. The cooler 50 is formed in a tubular shape so as to have a passage through which the refrigerant flows. Further, in the Z direction, the semiconductor devices 10 and the coolers 50 are arranged with a predetermined interval between the adjacent coolers 50 so that the semiconductor devices 10 and the coolers 50 are alternately laminated. In this way, the Z direction corresponds to the stacking direction.

The cooler 50 is one end side in the X direction, and adjacent coolers 50 are connected to each other by an upstream side connecting portion 51. The upstream side connecting portion 51 functions to distribute the supplied refrigerant to each cooler 50. On the other hand, on the other end side in the X direction, the adjacent coolers 50 are connected to each other by the downstream connecting portion 52. The downstream connecting portion 52 functions to merge the refrigerants distributed to each cooler 50.

The power modules shown in FIG. 13 include three semiconductor devices 10 that form upper and lower arms for three phases of the inverter 5, and a plurality of power modules that are alternately laminated with the semiconductor devices 10 so as to cool each semiconductor device 10 from both sides. The cooler 50 is provided. The semiconductor device 10 is sandwiched by the cooler 50 in the Z direction. Most of the sealing resin body 13 is arranged in the facing region of the adjacent coolers 50. The positive electrode terminal 22p, the negative electrode terminal 22n, and the output terminal 23 extend outside the facing region for connection with the corresponding bus bar.

(Concave and convex oxide film)
14 and 15 show a second heat sink 18H including a first joint 20a. The second heat sink 18H is formed with a concavo-convex oxide film 30 whose surface is continuously concavo-convex. As described above, the semiconductor device 10 includes the uneven oxide film 30. The uneven oxide film 30 is formed by irradiating a laser beam. Since the second heat sink 18L including the second joint portion 20b also has a common structure, it has the same configuration. Hereinafter, the second heat sink 18H will be described as an example.

As shown in FIGS. 14 and 15, the uneven oxide film 30 is formed on the mounting surface 18a and the side surfaces 18d and 18e of the second heat sink 18H, respectively. The semiconductor device 10 has a mounting surface roughening portion 31 and a side surface roughening portion 32 as roughened portions formed by the uneven oxide film 30. For clarification, in FIG. 14, the region where the uneven oxide film 30 is formed is hatched.

The mounting surface roughened portion 31 is formed with a concave-convex oxide film 30 formed on the mounting surface 18a. On the mounting surface 18a, the concave-convex oxide film 30 is not formed in the groove 18c and the region inside the groove 18c. The boundary 31a shown by the broken line in FIGS. 14 and 15 indicates the boundary between the formed region and the non-formed region of the uneven oxide film 30. The boundary 31a largely coincides with the outer circumference of the annular groove 18c. The boundary 31a is set to the outside of a part of the outer circumference. Specifically, with respect to the substantially rectangular annular groove 18c in which the four corners are rounded, the boundary 31a does not coincide with the outer peripheral portion of one of the four corners, and the boundary 31a is set outside the outer peripheral portion. As described above, in the present embodiment, the non-roughened region 31b in which the uneven oxide film 30 is not formed is intentionally provided between the outer circumference of the groove 18c and the boundary 31a.

When inspecting the misalignment of roughening due to laser light by an imaging means such as a camera, if all the contours of the boundary 31a, that is, the roughened portion 31 of the mounting surface are within the groove 18c, the contours cannot be focused and the contours can be recognized. It disappears. Therefore, even if the position shift occurs, it cannot be detected. On the other hand, in the present embodiment, since the non-roughened region 31b is provided between the outer circumference of the groove 18c and the boundary 31a, the misalignment can be reliably inspected.

Further, when inspecting a plurality of product numbers having different sizes of the mounted IGBTs 11H and 11L and different sizes of the grooves 18c, it is possible to detect roughening with an erroneous pattern. For example, if a pattern for large size should be roughened, even if it is accidentally roughened with a pattern for small size, at least a part of the non-roughened region 31b is outside the groove 18c, so that it is combined with the misalignment inspection. Mistakes in roughening patterns can also be inspected.

In the present embodiment, the mounting surface roughened portion 31 is integrally formed not only on the mounting surface 18a of the second heat sink 18H but also on the mounting surface of the first joint portion 20a connected to the second heat sink 18. In the first joint portion 20a, the uneven oxide film 30 is not formed in the groove 20d and the region inside the groove 20d, and the above-mentioned boundary substantially coincides with the outer periphery of the groove 20d on the entire circumference of the groove 20d. ing.

The side surface roughened portion 32 is formed with an uneven oxide film 30 formed on each of the side surfaces 18d and 18e. The side surface roughening portion 32 is formed only on the side surfaces 18d and 18e of the side surfaces of the second heat sink 18H. In the present embodiment, the side surface roughening portion 32 is integrally formed also in the first joint portion 20a connected to the second heat sink 18H. In the first joint portion 20a, the uneven oxide film 30 is formed on a surface connected to the side surface 18d. The entire surfaces of the side surfaces 18d and 18e of the second heat sink 18H and the surfaces of the first joint portion 20a connected to the side surface 18d are designated as side surface roughened portions 32.

As shown in FIG. 16, the uneven oxide film 30 is a part of the film 34 formed on the base material 33. The base material 33 is a metal member such as Cu that constitutes the second heat sink 18H including the first joint portion 20a. The film 34 has a metal thin film 35 formed on the surface of the base material 33 and an uneven oxide film 30.

In the present embodiment, the metal thin film 35 contains at least a film containing Ni as a main component. The metal thin film 35 is formed by, for example, plating or thin film deposition. The metal thin film 35 includes, for example, an electroless Ni plating film.

The metal thin film 35 is formed on the surface of the base material 33 except for the heat radiating surface 18b of the second heat sink 18H. On the surface of the metal thin film 35, a plurality of recesses 35a are formed in the portion where the mounting surface roughened portion 31 is formed and the portion where the side surface roughened portion 32 is formed. The film thickness of the metal thin film 35 is set to, for example, about 10 μm in the portion where the recess 35a is not formed. In other words, the film thickness before irradiation with the laser beam, which will be described later, is about 10 μm.

The recess 35a is formed by irradiating the laser beam of pulse oscillation. One recess 35a is formed for each pulse. The recess 35a is an irradiation mark of a laser beam. Adjacent recesses 35a are connected in the scanning direction of the laser beam. In the formed portions of the mounting surface roughened portion 31 and the side surface roughened portion 32, the surface of the metal thin film 35 is scaly due to a plurality of recesses 35a.

The width of each recess 35a is set to 5 μm to 300 μm. The depth of the recess 35a is set to 0.5 μm to 5 μm. If the depth of the recess 35a is shallower than 0.5 μm, the surface of the metal thin film 35 is not sufficiently melted and vapor-deposited by irradiation with a laser beam, and it becomes difficult to form the uneven oxide film 30. When the depth of the recess 35a is deeper than 5 μm, the surface of the metal thin film 35 is likely to be melt-scattered, surface formation by melt-scattering becomes dominant rather than vapor deposition, and the uneven oxide film 30 is less likely to be formed.

The concave-convex oxide film 30 is an oxide film of the same metal as the main component metal constituting the metal thin film 35. The uneven oxide film 30 is formed by oxidizing the metal constituting the metal thin film 35 by irradiating the metal thin film 35 with a laser beam. The uneven oxide film 30 is an oxide film formed on the surface of the metal thin film 35 by oxidizing the surface layer of the metal thin film 35. Since the uneven oxide film 30 is formed by irradiation with laser light, it can be said to be a laser irradiation film.

In the present embodiment, 80% of the components constituting the uneven oxide film 30 are NI ₂ O ₃ , 10% is NiO, and 10% is Ni. As described above, the main component of the concave-convex oxide film 30 is an oxide of Ni, which is the main component of the metal thin film 35.

The uneven oxide film 30 is formed on the surface of the recess 35a in the surface of the metal thin film 35. The average film thickness of the uneven oxide film 30 is 10 nm to several hundred nm. The uneven oxide film 30 is formed following the unevenness of the surface of the metal thin film 35 having the concave portions 35a. Further, on the surface of the uneven oxide film 30, unevenness is formed at a pitch finer than the width of the concave portion 35a. That is, very fine unevenness (roughened portion) is formed. In other words, a plurality of convex portions 30a (columnar bodies) are formed at a fine pitch. For example, the average width of the convex portions 30a is 1 nm to 300 nm, and the average spacing between the convex portions 30a is 1 nm to 300 nm. The average height of the convex portion 30a is 10 nm to several hundred nm.

As described above, the mounting surface roughened portion 31 and the side surface roughened portion 32 are formed by the uneven oxide film 30 on which very fine irregularities are formed on the surface. When the concave-convex oxide film 30 is provided, the wettability to the solder can be lowered as compared with the configuration without the concave-convex oxide film 30, that is, the configuration in which the surface of the metal thin film 35 is exposed. Therefore, the mounting surface roughening portion 31 can suppress the wetting and spreading of the solders 19 and 21.

Further, the sealing resin body 13 is entangled with the convex portion 30a on the surface of the uneven oxide film 30, and an anchor effect is generated. The unevenness increases the contact area with the sealing resin body 13. As a result, the sealing resin body 13 is brought into close contact with each of the mounting surface roughening portion 31 and the side surface roughening portion 32. Therefore, peeling of the sealing resin body 13 can be suppressed.

The uneven oxide film 30 can be formed by the following method. First, the second heat sink 18H on which the above-mentioned metal thin film 35 is formed is prepared.

Next, the uneven oxide film 30 is formed by irradiating the laser beam. The surface of the metal thin film 35 is melted and evaporated by irradiating the mounting surface 18a and the side surfaces 18d and 18e of the second heat sink 18H with a laser beam of pulse oscillation. Specifically, by irradiating with laser light, the surface portion of the metal thin film 35 is melted and evaporated (vaporized) to be suspended in the outside air.

Pulsed laser light energy density is large 100 J / cm ² or less than 0 J / cm ^2, the pulse width is adjusted to be equal to or less than 1μ seconds. This condition is satisfied, it is possible to adopt a YAG laser, YVO ₄ laser, such as a fiber laser with. For example, in the case of a YAG laser, the energy density may be 1 J / cm ² or more. In the case of electroless Ni plating, the metal thin film 35 can be processed even at about ^{5 J / cm 2, for example.}

At this time, by relatively moving the light source of the laser beam and the second heat sink 18H, the laser beam is sequentially irradiated to a plurality of positions. By irradiating the surface of the metal thin film 35 with laser light to melt and vaporize the surface of the metal thin film 35, a recess 35a is formed on the surface of the metal thin film 35. The average thickness of the portion of the metal thin film 35 irradiated with the laser beam is thinner than the average thickness of the portion not irradiated with the laser beam. Further, the plurality of recesses 35a formed corresponding to the spots of the laser beam are continuous in the X direction and also in the Y direction. As a result, the recess 35a, which is a laser irradiation mark, becomes, for example, a scale.

Next, the portion of the molten metal thin film 35 is solidified. Specifically, the molten and vaporized metal thin film 35 is vapor-deposited on the portion irradiated with the laser beam and the peripheral portion thereof. By depositing the molten and vaporized metal thin film 35 in this way, the uneven oxide film 30 is formed on the surface of the metal thin film 35. The uneven oxide film 30 is mainly formed on a portion of the metal thin film 35 irradiated with laser light.

^{When the energy density is made larger than 100 J / cm 2} in the irradiation of the laser beam, the uneven oxide film 30 is not formed. Further, the concave-convex oxide film 30 is not formed even when the laser beam of continuous oscillation is irradiated instead of pulse oscillation.

(Effect of semiconductor device)
FIG. 17 shows a comparative example. As a code of the comparative example, a code obtained by adding 100 to the code of the related element shown in the present embodiment is given. In the comparative example, although not shown, the uneven oxide film is formed only on the mounting surfaces of the second heat sinks 118H and 118L. That is, it has only a roughened mounting surface. The semiconductor device 110 is sandwiched between the coolers in the Z direction, and stress acts on the semiconductor device 110 while it is attached to the cooler. In the semiconductor device 110, of the second heat sink 118 and the first heat sink not shown in the drawing, only the first heat sink is extended from the side surface in the Y direction in the Y direction and protrudes from the sealing resin body 113. A positive electrode terminal 22p and an output terminal 123 are provided as parts. Therefore, stress is concentrated on the boundary portion between the side surface 118d of the second heat sink 118H and the sealing resin body 113, and the boundary portion between the side surface 118e of the second heat sink 118H and the sealing resin body 113. Due to such stress concentration, cracks 200 (cracks) as illustrated in the figure may occur in the sealing resin body 113. The crack 200 may occur along the X direction on the back surface 113b side.

On the other hand, in the present embodiment, as the roughened portion by the uneven oxide film 30, the side roughened portion 32 is provided in addition to the mounting surface roughened portion 31. As shown in FIG. 18, the side surface roughening portion 32 is formed on the side surface 18d corresponding to the side surface 14c in which the extending portions are continuous in the second heat sink 18H. Further, in the second heat sink 18L, it is formed on the side surface 18e corresponding to the side surface 14c in which the extending portions are connected. By providing the side surface roughening portion 32, the adhesion between the side surface where stress is concentrated and the boundary portion between the sealing resin body 13 in the laminated structure with the cooler 50 is higher than before. Therefore, cracks are suppressed in the sealing resin body 13 in the semiconductor device 10 in which stress acts due to stacking with the cooler 50 while locally providing a portion having high adhesion to the sealing resin body 13. can do.

In particular, in the present embodiment, the positive electrode terminals 22p and the output terminals 23 are connected as extending portions on the side surfaces 14c of the first heat sinks 14H and 14L. Since the positive electrode terminal 22p and the output terminal 23 are connected to the bus bar, the first heat sinks 14H and 14L are not easily deformed due to the stress of lamination. By that amount, the stress is concentrated on the boundary portion between the side surface 18d of the second heat sink 18H and the sealing resin body 13, and the boundary portion between the side surface 18e of the second heat sink 18H and the sealing resin body 13. However, it is possible to prevent cracks from being generated by the side surface roughened portion 32 formed by the uneven oxide film 30.

In the present embodiment, the IGBTs 11H and 11L are arranged side by side in the X direction, whereby the first heat sinks 14H and 14L and the second heat sinks 18H and 18L are also arranged side by side in the X direction. Due to this side-by-side arrangement, the length of the sealing resin body 13 is increased in the X direction orthogonal to the extension direction of the positive electrode terminal 22p and the output terminal 23, which are the extension portions. Therefore, stress tends to be concentrated on the boundary portion between the side surface 18d of the second heat sink 18H and the sealing resin body 13, and the boundary portion between the side surface 18e of the second heat sink 18H and the sealing resin body 13. However, it is possible to prevent cracks from being generated by the side surface roughened portion 32 formed by the uneven oxide film 30. In particular, since the side surface roughening portions 32 are provided on both the second heat sinks 18H and 18L, it is possible to suppress the occurrence of cracks even if the stress acts unevenly on either of them.

In the present embodiment, the side surface roughening portion 32 is also provided on the side surface of the joint portions 20a and 20b connected to the second heat sinks 18H and 18L. As described above, since the side surface roughening portion 32 is also provided in the thin-walled portion connected to the second heat sinks 18H and 18L which is the thick-walled portion, it is possible to effectively suppress the occurrence of cracks.

In the present embodiment, the hanging leads 26b as an extension portion are connected to the side surfaces 14d of the first heat sinks 14H and 14L. The suspension lead 26b is a free end in a laminated structure with the cooler 50. On the other hand, in the second heat sinks 18H and 18L, the side surface roughening portions 32 are provided on both the side surfaces 18d and 18e in the Y direction. That is, the side surface roughening portion 32 is also provided on the side surface 18e of the second heat sink 18H and the side surface 18d of the second heat sink 18H. Therefore, even if stress is concentrated on the boundary portion between the side surface 18e of the second heat sink 18H and the sealing resin body 13 and the boundary portion between the side surface 18d of the second heat sink 18H and the sealing resin body 13, cracks are generated. It can be suppressed.

Although an example in which the second heat sinks 18H and 18L are used as a common member is shown, the present invention is not limited to this. Members different from each other may be adopted, and the side surface roughening portion 32 may be provided only on the side surface 18d of the second heat sink 18H and only on the side surface 18e of the second heat sink 18L.

Further, an example is shown in which the uneven oxide film 30 (mounting surface roughened portion 31) is provided on the mounting surface 18a of the second heat sinks 18H and 18L, but the present invention is not limited to this. In addition to the mounting surface 18a, the uneven oxide film 30 may be provided on the mounting surface 14a of the first heat sinks 14H and 14L. The concave-convex oxide film 30 may be provided on the portion of the lead frame 26 on the mounting surface 18a side that is sealed by the sealing resin body 13 and excluding the mounting portion.

(Second Embodiment)
In this embodiment, the preceding embodiment can be referred to. Therefore, the description of the parts common to the semiconductor device 10 shown in the preceding embodiment will be omitted.

The second joint portion 20b connected to the second heat sink 18L on the lower arm side is connected to the negative electrode terminal 22n. By connecting the negative electrode terminal 22n, the second heat sink 18L is less likely to be deformed, and by being connected to the negative electrode terminal 22n to the bus bar, it is more difficult to be deformed.

On the other hand, the first joint portion 20a connected to the second heat sink 18H on the upper arm side is connected to the third joint portion 20c of the first heat sink 14L. Neither the main terminal is connected to the second heat sink 18H and the first joint portion 20a. Therefore, in the laminated structure with the cooler 50, stress tends to be concentrated on the boundary portion between the side surface 18d of the second heat sink 18H and the sealing resin body 13.

As shown in FIG. 19, in the present embodiment, the side surface roughening portion 32 is formed only on the side surface 18d of the side surface 18d of the second heat sink 18H and the side surface 18e of the second heat sink 18L. In this way, since the side surface roughening portion 32 is provided only on the side surface 18d where stress is likely to be concentrated, cracks are suppressed in the sealing resin body 13 while limiting the irradiation region of the laser beam to a narrower range. can do.

(Third Embodiment)
In this embodiment, the preceding embodiment can be referred to. Therefore, the description of the parts common to the semiconductor device 10 shown in the preceding embodiment will be omitted.

As shown in FIG. 20, in the present embodiment, of the side surfaces of the second heat sinks 18H and 18L, the side surface roughened portions 32 are formed not only on the side surfaces 18d and 18e in the Y direction but also on the side surfaces in the X direction. There is. Specifically, of the side surfaces in the X direction, the second heat sinks 18H and 18L are formed not on the surfaces facing each other, that is, on the surfaces on the joint portions 20a and 20b, but on the side surfaces 18f opposite to the facing surfaces. .. The side surface 18f corresponds to the third side surface.

As a result, the adhesion of the sealing resin body 13 to the side surface 18f is improved, so that even if stress acts on the boundary portion between the side surface 18f and the sealing resin body 13, cracks occur along this boundary portion. Can be suppressed.

Disclosure of this specification is not limited to the illustrated embodiments. The disclosure includes exemplary embodiments and modifications by those skilled in the art based on them. For example, disclosure is not limited to the combination of elements shown in the embodiments. Disclosure can be carried out in various combinations. The technical scope disclosed is not limited to the description of the embodiments. Some technical scopes disclosed are indicated by the description of the claims and should be understood to include all modifications within the meaning and scope equivalent to the description of the claims. ..

As the semiconductor device 10, an example of a 2in1 package structure including two semiconductor elements (IGBT11H, 11L) has been shown, but the present invention is not limited thereto. It can also be applied to a 1in1 package structure including one semiconductor element constituting one arm and a 6in1 package structure including six semiconductor elements constituting three-phase upper and lower arms. In the case of a 1in1 package, it has only one set of a first heat sink and a second heat sink, and is applied to a configuration in which the main terminals are connected to the side surface of the first heat sink and the main terminals are not connected to the side surface of the second heat sink in the Y direction. can. For the second heat sink, for example, the main terminals are connected to the side surface in the X direction.

An example is shown in which the FWD 12H and 12L are integrally formed with the IGBT 11H and 11L, but the present invention is not limited to this. As shown in FIG. 21, the IGBTs 11H and 11L and the FWD 12H and 12L may be separate elements. Reference numeral 36 shown in FIG. 21 is a mounting surface roughening portion formed on the mounting surface side of the lead frame 26.

An example is shown in which the heat radiating surfaces 14b of the first heat sinks 14H and 14L and the heat radiating surfaces 18b of the second heat sinks 18H and 18L are exposed from the sealing resin body 13, but the present invention is not limited thereto. At least one of the heat radiating surfaces 14b and 18b may be covered with the sealing resin body 13.

The metal constituting the metal thin film 35 is not limited to Ni. That is, the uneven oxide film 30 is not limited to the oxide of Ni. The concave-convex oxide film 30 may be an oxide film of the same metal as the metal constituting the metal thin film 35.

1 ... Power converter, 2 ... DC power supply, 3 ... Motor, 4 ... Smoothing capacitor, 5 ... Inverter, 6 ... Positive electrode side line, 7 ... Negative electrode side line, 8 ... Output line, 10 ... Semiconductor device, 11H, 11L ... IGBT, 11c ... collector electrode, 11e ... emitter electrode, 11g ... gate electrode, 11p ... pad, 12H, 12L ... FWD, 13 ... sealing resin body, 13a ... one side, 13b ... back side, 13c, 13d ... side surface, 14H, 14L ... 1st heat sink, 14a ... mounting surface, 14b ... heat dissipation surface, 14c, 14d ... side surface, 15 ... solder, 16 ... terminal, 17 ... solder, 18H, 18L ... second heat sink, 18a ... mounting surface, 18b ... heat dissipation Surface, 18c ... Groove, 18d, 18e, 18f ... Side surface, 19 ... Solder, 20 ... Joint part, 20a ... First joint part, 20b ... Second joint part, 20c ... Third joint part, 20d ... Groove, 21 ... Solder, 22 ... Power supply terminal, 22p ... Positive electrode terminal, 22n ... Negative electrode terminal, 23 ... Output terminal, 24, 24a, 24b ... Signal terminal, 25 ... Bonding wire, 26 ... Lead frame, 26a ... Outer frame, 26b ... Suspended lead , 26c ... tie bar, 30 ... uneven oxide film, 30a ... convex portion, 31 ... mounting surface roughened portion, 31a ... boundary, 31b ... non-roughened region, 32 ... side surface roughened portion, 33 ... base material, 34 ... film , 35 ... Metal thin film, 35a ... Recessed portion, 36 ... Roughened portion, 50 ... Cooler, 51 ... Upstream side connecting portion, 52 ... Downstream side connecting portion

Claims (4)

A semiconductor device that is laminated with a cooler (50) and is sandwiched and held by the cooler in the stacking direction.
At least one semiconductor element (11H, 11L) having a main electrode (11c, 11e) formed on one surface in the stacking direction and the back surface opposite to the one surface, respectively.
First heat radiating parts (14H, 14L) electrically connected to the main electrode on one side, and the main electrode on the back side, which are heat radiating parts arranged so as to sandwich the semiconductor element in the stacking direction. The second heat dissipation part (18H, 18L) electrically connected to the
A sealing resin body (13) that integrally seals at least a part of the first heat radiating portion, at least a part of the second heat radiating portion, and the semiconductor element.
The first heat-dissipating portion of the heat-dissipating portion, which is connected to the first side surface (14c) in one direction orthogonal to the stacking direction, extends from the first side surface in the one direction, and the sealing resin. Extensions (22p, 23) protruding from the body and
It is a film (34) formed on the surface of the heat radiating portion and the sealing portion by the sealing resin body, and is formed on the metal thin film (35) and the metal thin film, and is the main component of the metal thin film. Concavo-convex oxide film (30), which is an oxide film of the same metal as the metal of No. 1 and whose surface is continuously uneven.
With
The uneven oxide film, and formed mounting surface roughened portion to surround the connecting portion between the main electrode in the mounting surface of the heat radiating portion (31), of the side surfaces of the second heat radiating unit, said first A semiconductor device having a side surface roughened portion (32) formed only on the second side surface (18d, 18e) corresponding to the side surface. The semiconductor device according to claim 1, wherein the extending portion is a main terminal electrically connected to the main electrode via the first heat radiating portion. As the semiconductor element, the upper arm element constituting the upper arm of the upper and lower arms and the upper arm element forming the lower arm are arranged side by side with the upper arm element in the first direction which is one direction and the second direction orthogonal to the stacking direction. With an arranged lower arm element,
The heat radiating portion includes two sets of the first heat radiating portion and the second radiating portion arranged so as to individually sandwich the upper arm element and the lower arm element in the stacking direction.
As the main terminal, a first main terminal connected to the first heat radiating portion corresponding to the upper arm element and a first main terminal connected to the first heat radiating portion corresponding to the lower arm element and extending in the same direction as the first main terminal. Has a second main terminal provided,
A third main terminal connected to the second heat radiating portion corresponding to the lower arm element via a joining member and extended in the same direction as the first main terminal.
Joint portions (20a, 20c) that electrically connect the second heat radiating portion arranged on the low potential side of the upper arm element and the first heat radiating portion arranged on the high potential side of the lower arm element. When,
With more
The semiconductor device according to claim 2, wherein the side surface roughening portion is formed on at least one of the second heat radiating portion corresponding to the upper arm element and the second heat radiating portion corresponding to the lower arm element. The semiconductor device according to claim 3, wherein the side surface roughening portion is formed only in the second heat radiating portion corresponding to the upper arm element.

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