JP6772673B2 - Manufacturing method of semiconductor devices - Google Patents

Description

This specification discloses a method for manufacturing a semiconductor device including two or more semiconductor elements.

A semiconductor device in which metal heat radiating plates are exposed on both sides of a resin main body that seals two or more semiconductor elements is known. Such semiconductor devices are disclosed, for example, in Patent Documents 1 and 2.

Patent Document 1 also discloses a method for manufacturing the semiconductor device. First, a transistor and a diode (that is, two semiconductor elements) are fixed to the surface of the first heat radiating plate in a positional relationship with a distance between them. Then, the second heat radiating plate is arranged so as to face the surface of the first heat radiating plate with the two semiconductor elements sandwiched between the first heat radiating plate. After arranging the second heat radiating plate, a primer (primer) is applied to the surfaces (inner surfaces) of the first heat radiating plate and the second heat radiating plate facing each other. After applying the primer, a resin is filled between the first heat radiating plate and the second heat radiating plate to form a resin body for sealing a plurality of semiconductor elements. Since the undercoating agent to be applied has fluidity and penetrates into the gap between the first heat radiating plate and the second heat radiating plate, it can be applied after the second heat radiating plate is arranged.

Japanese Patent Application No. 2015-126119 Japanese Patent Application No. 2016-115704

There is a desire to inspect the applied undercoat after applying the undercoat. For example, there is a desire to inspect whether or not air bubbles are present in the applied primer. However, in the conventional manufacturing method, the undercoating agent is applied after the second heat radiating plate is arranged. Therefore, even when observing the applied undercoating agent, the view is blocked by the second heat radiating plate and the inner surface of the first heat radiating plate is applied. It is difficult to observe the primer applied to. In particular, in the inner surface of the first heat radiating plate, the region located between the semiconductor elements is obstructed by the semiconductor element, so that it is more difficult to observe the undercoating agent applied to the region. is there. That is, in the conventional manufacturing method, it is very difficult to observe the undercoating agent applied to the region between the semiconductor elements.

The techniques disclosed herein facilitate observation of the primer applied to the region between the semiconductor elements. If it becomes easy to observe, it becomes possible to inspect the primer after application.

The method for manufacturing a semiconductor device disclosed in the present specification includes a first fixing step of fixing two or more semiconductor elements on the surface of a first heat radiation plate in a positional relationship separated from each other, and a first fixing step thereof. After the fixing step, a coating step of applying an undercoating agent to the surface of the first heat radiating plate (the surface facing the second heat radiating plate, which is referred to as an inner surface in the present specification), and after the coating step, the first heat dissipation. The arrangement process of arranging the second heat radiating plate so as to face the first heat radiating plate with two or more semiconductor elements sandwiched between the plates, and the two or more semiconductor elements directly or with a conductive material. Through the second fixing step of fixing to the surface of the second heat radiating plate (the surface facing the first heat radiating plate, which is referred to as the inner surface in the present specification), and the inner surface of the first heat radiating plate and the second heat radiating plate. It is provided with a molding step of filling a resin between the inner surfaces and molding a resin body for sealing two or more semiconductor elements. In the above, the distance between the heat generating portion of the two or more semiconductor elements and the second heat radiating plate is longer than the distance between the heat generating portion of the two or more semiconductor elements and the first heat radiating plate. The description that the undercoating agent is applied to the inner surface of the first heat radiating plate means that the undercoating agent is applied to a region of the inner surface of the first heat radiating plate to which the semiconductor element is not fixed.

With the above configuration, it is possible to obtain a state in which the inner surface of the first heat radiating plate can be observed without being blocked by the second heat radiating plate after the coating step. On the inner surface of the first heat radiating plate, a region located between the semiconductor elements can also be observed. After the observation, the process of arranging the second heat radiating plate can be carried out. After inspecting the applied primer, the process of arranging the second heat radiating plate can be carried out.

In the technique disclosed in the present specification, the observation of the undercoating agent applied to the first heat radiating plate is prioritized over the application of the undercoating agent to both the first heat radiating plate and the second heat radiating plate. When the semiconductor device generates heat, the stress of peeling the heat radiating plate and the resin body between the first heat radiating plate and the resin body and between the second heat radiating plate and the resin body due to the difference in the coefficient of thermal expansion between the metal and the resin. Works. When the first heat radiating plate and the resin body are separated from each other due to the stress, the stress also acts on the fixed portion between the first heat radiating plate and the semiconductor element, and the semiconductor element may be damaged. In the present technology, since the coating process is performed before the process of arranging the second heat radiating plate, the applied undercoating agent can be inspected. Since the coating is incomplete, the phenomenon that the first heat radiating plate and the resin body are peeled off is unlikely to occur.

On the other hand, no undercoating agent is applied to the second heat radiating plate. When the second heat radiating plate is fixed to the semiconductor element via the conductive material, the distance between the heat generating portion of the semiconductor element and the second heat radiating plate is longer than the distance between the heat generating portion of the semiconductor element and the first heat radiating plate. In this case, even if the second heat radiating plate and the resin body are peeled off, the stress caused by the peeling is unlikely to act on the semiconductor element, and the semiconductor element is not easily damaged. That is, the peeling of the first heat radiating plate and the resin body causes damage to the semiconductor element, but the peeling of the second heat radiating plate and the resin body is unlikely to cause damage to the semiconductor element.

Even when the semiconductor element is directly fixed to the second heat radiating plate, the distance between the heat generating portion of the semiconductor element and one heat radiating plate and the distance between the heat generating portion of the semiconductor element and the other heat radiating plate may be different. .. When the distances from the heat generating portion of the semiconductor element to the heat radiating plate are different, the heat radiating plate on the side with the short distance is referred to as the first heat radiating plate, and the heat radiating plate on the side with the long distance is referred to as the second heat radiating plate. When the distance from the heat generating portion to the second heat radiating plate is longer than the distance from the heat generating portion to the first heat radiating plate, the stress acting between the first heat radiating plate and the resin body is between the second heat radiating plate and the resin body. Greater than the stress acting on. The first heat radiating plate and the resin body are easily peeled off, and the second heat radiating plate and the resin body are hard to be peeled off. In this technique, no undercoating agent is applied to the second heat radiating plate. Since the second heat radiating plate and the resin body are difficult to peel off, no problem occurs even if the undercoating agent is not applied to the second heat radiating plate.

Actually, the merit of being able to observe the undercoating agent applied to the inner surface of the first heat radiating plate is greater than the demerit of not applying the undercoating agent to the inner surface of the second heat radiating plate.

It is a block diagram of the electric power system of the electric vehicle provided with the semiconductor device of an Example. It is a top view of the semiconductor device of an Example. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. It is the first figure which shows the manufacturing process of a semiconductor device. It is a 2nd figure which shows the manufacturing process of a semiconductor device. FIG. 3 is a third diagram showing a manufacturing process of a semiconductor device.

First, the features of the examples described below are listed.
Feature 1: In the second fixing step, each of two or more semiconductor elements is fixed to the second heat radiating plate via a conductive material.
Feature 2: When the heat radiating plate is viewed in a plan view, the area of each conductive material is smaller than the area of each semiconductor element fixed to each conductive material.
Feature 3: The area of the region where the semiconductor element is fixed in the first heat radiating plate is larger than the area of the region where the conductive material is fixed in the second heat radiating plate.
Feature 4: The semiconductor element is directly fixed and the inner surface of the first heat radiating plate having a large fixed area is coated with an undercoating agent to prevent the first heat radiating plate and the resin body from peeling off. The undercoating agent is not applied to the inner surface of the second heat radiating plate in which the semiconductor element is fixed via the conductive material and the fixed area thereof is small.

(Example)
The semiconductor device 20 of the embodiment will be described with reference to the drawings. The technique disclosed in the present specification is applied to a semiconductor device 20 mounted on an electric vehicle 100. FIG. 1 is a block diagram of an electric power system of the electric vehicle 100. The electric vehicle 100 includes a battery 101, a system main relay 102, a voltage converter 103, an inverter 104, and a traveling motor 105. The battery 101 and the motor 105 are connected to each other via the system main relay 102, the voltage converter 103, and the inverter 104. The electric power of the battery 101 is supplied to the motor 105 via the voltage converter 103 and the inverter 104. As a result, the motor 105 is driven and the electric vehicle 100 runs. In this case, the voltage converter 103 boosts the DC power from the battery 101, and the inverter 104 converts the DC power from the voltage converter 103 into AC power.

On the other hand, when the electric vehicle 100 is braked, the electric power generated by the motor 105 is supplied to the battery 101 via the voltage converter 103 and the inverter 104. As a result, the electric power generated by the motor 105 is charged into the battery 101. In this case, the inverter 104 converts the AC power from the motor 105 into DC power, and the voltage converter 103 steps down the DC power from the inverter 104. Since the circuit configuration of the inverter 104 is well known, the circuit configuration of the inverter 104 is not shown in FIG. Further, since the principle of the inverter 104 is well known, the description thereof will be omitted.

The voltage converter 103 will be described. The voltage converter 103 includes two diodes 21, 51, two IGBTs (abbreviation of Insulated Gate Bipolar Transistor) 22, 52, two capacitors (signs omitted), and a reactor (signs omitted). .. The two IGBTs 22 and 52 are connected in series. The diode 21 is connected in parallel with the IGBT 22. Specifically, the cathode electrode of the diode 21 and the collector electrode of the IGBT 22 are connected, and the anode electrode of the diode 21 and the emitter electrode of the IGBT 22 are connected. Similarly, the diode 51 is also connected in parallel with the IGBT 52. Each capacitor and reactor constitutes the circuit of the voltage converter 103, as shown in FIG. Since the principle of the voltage converter 103 is well known, the description thereof will be omitted.

The parallel circuit of the diode 21 and the IGBT 22 is realized as the semiconductor device 20. The semiconductor device 20 includes output terminals 41 and 42 and a gate terminal 43. One end of the parallel circuit (that is, the collector electrode of the IGBT 22) is connected to the output terminal 41, and the other end (that is, the emitter electrode of the IGBT 22) is connected to the output terminal 42. The gate terminal 43 is connected to the gate electrode of the IGBT 22. The gate terminal 43 is connected to a control device (not shown) for controlling switching of the IGBT 22. Similarly, the parallel circuit of the diode 51 and the IGBT 52 is also realized as the semiconductor device 50.

The semiconductor device 20 will be described with reference to FIGS. 2 and 3. FIG. 2 is a plan view of the semiconductor device 20, and FIG. 3 is a cross-sectional view taken along the line III-III of FIG. The XYZ coordinates are shown in the figure. Hereinafter, the configuration of the semiconductor device 20 will be described by appropriately using the XYZ coordinates.

The semiconductor device 20 includes a resin body 28 that seals the diode 21 and the IGBT 22, heat radiating plates 23 and 24 for radiating heat from the diode 21 and the IGBT 22, output terminals 41 and 42, and a gate terminal 43. , Is equipped. The heat radiating plates 23 and 24 are made of metal (for example, copper). The heat radiating plates 23 and 24 are arranged in parallel and face each other. The outer surface of the first heat radiating plate 23 is exposed from one of the two surfaces of the resin body 28 in the X-axis direction, and the portion of the first heat radiating plate 23 other than the outer surface is exposed to the resin body 28. It is covered. Similar to the first heat radiating plate 23, the outer surface of the second heat radiating plate 24 is also exposed from the other side of both sides of the resin body 28. The semiconductor device 20 is sandwiched between two coolers (not shown). Each cooler faces one of a pair of outer surfaces of the resin body 28 via an insulating plate (not shown). As a result, each cooler comes into contact with each heat dissipation plate via the insulating plate, and the heat from the diode 21 and the IGBT 22 is transferred to each cooler.

The cathode electrode 21a of the diode 21 is connected to the inner surface of the first heat radiating plate 23 by the solder 31a. A collector electrode 22a of the IGBT 22 is connected to the inner surface by a solder 32a. The diode 21 and the IGBT 22 are arranged at a distance from each other. The first heat radiating plate 23 and the output terminal 41 are formed from one metal plate. That is, the first heat radiating plate 23 also serves as a part of the current path from the diode 21 and the IGBT 22 to the output terminal 41.

The anode electrode 21b of the diode 21 is connected to the inner surface of the second heat radiating plate 24 via a block-shaped conductive material 25. The lower surface of the conductive material 25 is connected to the anode electrode 21b by the solder 31b, and the upper surface of the conductive material 25 is connected to the second heat radiating plate 24 by the solder 31c. Further, the emitter electrode 22b of the IGBT 22 is further connected to the inner surface of the second heat radiating plate 24 via the conductive material 26. Like the conductive material 25, the conductive material 26 is connected to the emitter electrode 22b and the second heat radiating plate 24 by solders 32b and 32c, respectively. The second heat radiating plate 24 and the output terminal 42 are formed from one metal plate. That is, the second heat radiating plate 24 also serves as a part of the current path from the diode 21 and the IGBT 22 to the output terminal 42.

The gate electrode (reference numeral omitted) of the IGBT 22 is connected to the gate terminal 43 via a wire (not shown). The gate electrode is located on the same surface as the surface on which the emitter electrode 22b of the IGBT 22 is located. The conductive material 26 is connected to the emitter electrode 22b so as not to overlap the gate electrode. The conductive material 26 connects the emitter electrode 22b and the second heat radiating plate 24, and secures a space for arranging the wire connecting the gate electrode and the gate terminal 43 between the second heat radiating plate 24 and the IGBT 22. The purpose.

Further, when observed from the surface where the emitter electrode 22b is located (that is, when the first heat radiating plate 23 is viewed in a plan view), the area of the conductive material 26 is smaller than the area of the IGBT 22 (see FIG. 2). When the first heat radiating plate 23 is viewed in a plan view, the area of the conductive material 25 is also smaller than the area of the diode 21, and the conductive material 25 is arranged inside the width of the diode 21. Due to this relationship, the area of the first heat radiating plate 23 to which the two semiconductor elements (21 and 22) are not connected is the area of the two conductive materials on the inner surfaces of the first heat radiating plate and the second heat radiating plate facing each other. It is smaller than the area of the second heat radiating plate 24 to which (25 and 26) are not connected. Further, as shown in FIG. 3, the distance L1 between the diode 21 and the IGBT 22 is smaller than the distance L2 between the conductive materials 25 and 26.

The primer 33 is applied to the region of the inner surface of the first heat radiating plate 23 where the diode 21 and the IGBT 22 are not fixed. Hereinafter, the area to which the undercoating agent 33 is applied is referred to as a coating area. The undercoating agent 33 is for adhering a metal and a resin, and for example, a polyamide resin is a main component. The first heat radiating plate 23 and the resin body 28 are in close contact with each other by the undercoating agent 33. In FIG. 3, a region between the diode 21 and the IGBT 22 in the coating region is designated by reference numeral 23a, and the primer coated in the region 23a is designated by reference numeral 33a. Further, a reference numeral 23b is attached to a region other than the region 23a in the coating region, and a reference numeral 33b is attached to the primer coated on the region 23b. The second heat radiating plate 24 is not coated with an undercoating agent.

The primer 33a is applied not only to the coating region 23a but also to the boundary between the diode 21 and the coating region 23a (that is, the first heat radiating plate 23). As a result, the boundary also adheres to the resin body 28. Further, the undercoating agent 33a is a conductive material among the side surface of the diode 21 extending from this boundary in the X-axis direction and the surface on the side to which the conductive material 25 of the diode 21 is connected (that is, the surface on which the anode electrode 21b is located). It is also applied to the area to which 25 is not connected. As a result, the metal portion (for example, the electrode) of the diode 21 comes into close contact with the resin body 28. Further, the undercoating agent 33a is also applied to the boundary between the region where the conductive material 25 of the diode 21 is not connected and the solder 31b. As a result, the solder 31b comes into close contact with the resin body 28.

Similarly, the primer 33a is the boundary between the IGBT 22 and the coating region 23a, the region of the side surface of the IGBT 22 and the side surface where the emitter electrode 22b is located where the conductive material 26 is not connected, and the boundary between the region and the solder 32b. It is also applied to. Similarly, the undercoating agent 33b also has a boundary between the two semiconductor elements (21 and 22) and the first heat radiation plate 23, each side surface extending from each boundary of the two semiconductor elements, and a surface on which each electrode is located. It is also applied to the boundary between the surface on which each electrode is located and each solder.

The diode 21 and the IGBT 22 generate heat due to the flow of an electric current. The heat from the two semiconductor elements (21 and 22) is transferred to the heat radiating plates 23 and 24 and the resin body 28 to expand the members 23, 24 and 28. When each member 23, 24, 28 expands, due to the difference in the coefficient of thermal expansion between the metal and the resin, each heat radiating plate is placed between the first heat radiating plate 23 and the resin body 28 and between the second heat radiating plate 24 and the resin body 28. The stress that 23 and 24 try to separate from the resin body 28 acts. Since the undercoating agent 33 is applied between the first heat radiating plate 23 and the resin body 28 (that is, the coating region 23a and the boundary between the region 23a and the semiconductor element), the stress causes the first heat dissipation from the resin body 28. The plate 23 is prevented from peeling off. As a result, the stress is prevented from acting on the solders 31a and 32a connecting the first heat radiating plate 23 and the semiconductor element, and the semiconductor element is prevented from being damaged.

The primer is also applied to the surface on which the electrodes of the semiconductor element are located and the boundary between the surface and the solder. As a result, the surface on which the electrodes of the semiconductor element are located is prevented from peeling from the resin body 28, and the semiconductor element is prevented from being damaged by the peeling.

On the other hand, no undercoating agent is applied between the second heat radiating plate 24 and the resin body 28. However, the second heat radiating plate 24 is connected to the two semiconductor elements via the two conductive materials (25 and 26). Even if the second heat radiating plate 24 is peeled off from the resin body 28, the stress due to expansion acts on the solder (31c and 32c) between the second heat radiating plate 24 and the conductive material, and the solder between the conductive material and the semiconductor element. It is difficult to act on (31b and 32b). Further, between the first heat radiating plate 23 and the second heat radiating plate 24, the distance between the semiconductor element which is a heat generating source and the second heat radiating plate 24 is such that the semiconductor element and the first heat radiating plate 23 are separated by the presence of the conductive material. Longer than the distance between. The stress due to expansion becomes smaller between the first heat radiating plate 23 near the heat source and the second heat radiating plate 24 far from the heat source. That is, even if the second heat radiating plate 24 is peeled from the resin body 28, the stress acting on the solder between the conductive material and the semiconductor element is small. Even if the second heat radiating plate 24 is peeled from the resin body 28, the semiconductor element is not easily damaged.

The peeling of the first heat radiating plate 23 is a main cause of damage to the semiconductor element. By applying the undercoating agent 33 to the first heat radiating plate 23, the peeling of the first heat radiating plate 23 is prevented preferentially over the peeling of the second heat radiating plate 24. As will be described in detail later, applying the undercoating agent 33 to the first heat radiating plate 23, which needs to prevent peeling, makes it easy to observe the undercoating agent 33 in the manufacturing process of the semiconductor device 20.

Further, the area of the area where the two semiconductor elements are not connected on the inner surface of the first heat radiating plate 23 is the area where the two conductive materials are not connected on the inner surface of the second heat radiating plate 24. Is smaller than the area of. That is, the contact area between the second heat radiating plate 24 and the resin body 28 is larger than the contact area between the first heat radiating plate 23 and the resin body 28. Therefore, the force acting on the contact surface of the second heat radiating plate 24 with the resin body 28 due to the stress due to expansion acts on the contact surface of the first heat radiating plate 23 with the resin body 28 due to the stress. Less than the force to do. Since the acting force is small, the second heat radiating plate 24 is more difficult to peel off from the resin body 28 than the first heat radiating plate 23. Even if the undercoating agent 33 is applied only to the first heat radiating plate 23 without applying the undercoating agent to the second heat radiating plate 24, damage to the semiconductor element can be prevented.

Further, by applying the undercoating agent 33 only to the first heat radiating plate 23 without applying the undercoating agent to the second heat radiating plate 24, the adhesion between the second heat radiating plate 24 and the resin body 28 becomes the first heat radiating plate. It becomes fragile due to the close contact between the 23 and the resin body 28. As a result, when stress is generated due to expansion, the second heat radiating plate 24 can be peeled off before the first heat radiating plate 23. Since the second heat radiating plate 24 is peeled off first, the first heat radiating plate 23, which is a main cause of damage to the semiconductor element, is less likely to be peeled off. It is possible to prevent damage to the semiconductor element.

A method of manufacturing the semiconductor device 20 will be described with reference to FIGS. 4 to 6. The manufacturing method of the semiconductor device 20 includes a first fixing step, a coating step, an inspection step, an arrangement step, a second fixing step, and a molding step. 4 to 6 are cross-sectional views of the semiconductor device 20 in the process of being manufactured in each process as viewed from the same direction as in FIG. Note that in FIGS. 4 to 6, the output terminals 41 and 42 and the gate terminal 43 are not shown.

FIG. 4 shows the first fixing step. In the first fixing step, the diode 21 is fixed to the surface of the first heat radiating plate 23 by the solder 31a, and the IGBT 22 is fixed to the surface of the first heat radiating plate 23 by the solder 32a at a position away from the diode 21. Ru. The surface on which the diode 21 and the IGBT 22 are fixed is the inner surface of the first heat radiating plate 23. Then, each of the conductive materials 25 and 26 is fixed to the diode 21 and the IGBT 22 by the solders 31b and 32b, respectively. Further, in the first fixing step, wire bonding for connecting the gate terminal 43 and the gate electrode of the IGBT 22 with a wire is also executed.

FIG. 5 shows a coating process and an inspection process. The coating step is carried out after the first fixing step. In the coating step, the primer 33 is applied to the coating regions 23a and 23b on the inner surface of the first heat radiating plate. As described above, the primer 33 is also applied to each boundary and each surface of the two semiconductor elements (21 and 22).

The inspection step is carried out after the coating step. In the inspection step, the undercoating agent 33 applied to the coating areas 23a and 23b is inspected. This inspection confirms the presence or absence of air bubbles in the primer 33. The absence of air bubbles in the undercoat 33 means that the first heat radiating plate 23 and the resin body 28 are in close contact with each other as designed. This inspection is carried out by observing the first heat radiating plate 23 in a plan view as shown by the arrows in the drawing. After the coating step, since there is no member that blocks the coating regions 23a and 23b in a plan view, it is easy to observe the coating regions 23a and 23b. In particular, when the second heat radiating plate 24 is arranged, the coating region 23a between the diode 21 and the IGBT 22 is obstructed by the second heat radiating plate 24 and the two semiconductor elements (21 and 22) and can be observed. Have difficulty. After the coating step, the distance L1 between the semiconductor elements is smaller than the distance L2 between the conductive materials, and the second heat radiating plate 24 is not arranged, so that the coating region 23a can be observed. .. By carrying out the inspection step after the coating step, the coating region 23a can be easily observed.

FIG. 6 shows a placement step and a second fixing step. The placement step is performed after the inspection step (ie, the coating step). In the arranging step, the second heat radiating plate 24 is arranged so as to face the first heat radiating plate 23 with the two semiconductor elements (21 and 22) sandwiched between the first heat radiating plate 23. The second fixing step is carried out after the placement step. In the second fixing step, the conductive materials 25 and 26 are fixed to the second heat radiating plate 24 by the solders 31c and 32c, respectively.

The molding step is carried out after the second fixing step. In the molding step, the resin body 28 is molded by accommodating the semiconductor device 20 in the process of manufacturing shown in FIG. 6 in a mold that imitates the outer shape of the resin body 28 and filling the mold with resin. That is, in the molding step, resin is filled between the inner surface of the first heat radiating plate 23 and the inner surface of the second heat radiating plate 24, and the two semiconductor elements (21 and 22) are sealed by the resin body 28. .. When the molding process is completed, the semiconductor device 20 is completed (see FIG. 3).

According to this manufacturing method, a state in which the coating regions 23a and 23b can be observed can be obtained after the coating step, and the inspection step can be carried out. Then, the placement step can be carried out after the inspection step.

The points to be noted regarding the techniques shown in the examples will be described below. The semiconductor device 20 does not have to include the conductive materials 25 and 26. That is, the two semiconductor elements (21 and 22) may be directly fixed to the second heat radiating plate 24. In this case, the two semiconductor elements have a second heat radiating plate so that the distance between the heat generating portion and the second heat radiating plate 24 is longer than the distance between the heat generating portion of the semiconductor element and the first heat radiating plate 23. It is fixed at 24. In other words, between the first heat radiating plate 23 and the second heat radiating plate 24, the heat generating portion of the semiconductor element is offset to the side where the first heat radiating plate 23 is located. As a result, the stress acting between the first heat radiating plate 23 and the resin body 28 becomes smaller than the stress acting between the second heat radiating plate 24 and the resin body 28, and the same effect as in the embodiment is obtained. Be done.

The conductive materials 25 and 26 may be fixed to each semiconductor element after the coating step and the inspection step. In this case, the primer 33 does not have to be applied to the surface on which the electrodes of each semiconductor element are located and the boundary between the surface and the solder. Generally speaking, at least the inner surface of the first heat radiating plate may be coated with the primer.

The diode 21 and the IGBT 22 are examples of "two or more semiconductor elements". The types of semiconductor elements are not limited to diodes and IGBTs. For example, MOSFET (abbreviation of Metal Oxide Semiconductor Field Effect Transistor) may be used. Further, the technique of the embodiment is not limited to the configuration of the embodiment, and can be applied to a semiconductor device including two or more IGBTs, a semiconductor device including three or more semiconductor elements including an IGBT and a diode, and the like.

The anode electrode 21b of the diode 21 and the emitter electrode 22b of the IGBT 22 may be connected to the first heat radiating plate 23, and the cathode electrode 21a and the collector electrode 22a may be connected to the second heat radiating plate 24.

A preventive means for preventing the second heat radiating plate 24 from peeling from the resin body 28 may be provided between the second heat radiating plate 24 and the resin body 28. The preventive means is, for example, a structure such as a groove, a ridge or a dimple provided on the inner surface of the second heat radiating plate 24. This structure enhances the adhesion between the second heat radiating plate 24 and the resin body 28 by increasing the contact area between the second heat radiating plate 24 and the resin body 28.

The technique of the embodiment can also be applied to a semiconductor device including one semiconductor element. That is, in a semiconductor device including one semiconductor element, an undercoating agent is applied to the inner surface of a first heat radiating plate that is close to the heat generating portion of the semiconductor element, and a second heat radiating plate that is far from the heat generating portion. It is not necessary to apply an undercoating agent to the inner surface of the. In this modified example as well, as in the embodiment, it is possible to facilitate the observation of the undercoat agent while preventing damage to the semiconductor element due to peeling of the heat radiating plate from the resin body.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above. The technical elements described herein or in the drawings exhibit their technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques illustrated in the present specification or drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

20: Semiconductor device 21: Diode 22: IGBT
23: First heat radiating plate 24: Second heat radiating plate 25, 26: Conductive material 28: Resin body 31a-31c, 32a-32c: Solder 33a, 33b: Undercoating agent 41, 42: Output terminal 43: Gate terminal

Claims (1)

The first fixing step of fixing two or more semiconductor elements on the surface of the first heat radiating plate in a positional relationship separated from each other.
After the first fixing step, a coating step of applying an undercoating agent to the inner surface of the first heat radiating plate, and
Without applying the undercoating agent to the surface of the second heat radiating plate, after the coating step, the first heat radiating plate is faced with the two or more semiconductor elements sandwiched between the first heat radiating plate. The arrangement step of arranging the second heat radiating plate and
A second fixing step of fixing the two or more semiconductor elements to the inner surface of the second heat radiating plate directly or via a conductive material.
A resin is filled between the inner surface of the first heat radiating plate coated with the undercoat agent and the inner surface of the second heat radiating plate not coated with the undercoating agent to seal the two or more semiconductor elements. The molding process of molding the resin body to be stopped and
Is equipped with
Manufacture of a semiconductor device characterized in that the distance between the heat generating portion of the two or more semiconductor elements and the second heat radiating plate is longer than the distance between the heat generating portion of the two or more semiconductor elements and the first heat radiating plate. Method.

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