JP2024139935A - Semiconductor device and power conversion device - Google Patents

Abstract

To provide a technique capable of improving heat dissipation property while maintaining an insulation property in a semiconductor device.SOLUTION: A semiconductor device 100 comprises: a lead frame 3 that includes a die pad 5; a semiconductor element 1 that is mounted on a front surface in the die pad 5; a mold resin 6 that seals the semiconductor element 1 and the lead frame 3 in a state where a back surface on a side opposite to the front surface in the die pad 5 is exposed; and a heat sink 9 that is arranged via a grease 8 on a bottom surface where the back surface of the die pad 5 in the mold resin 6 is exposed. On the bottom surface where the back surface of the die pad 5 in the mold resin 6 is exposed, a projection part 7 whose tip end comes into contact with the heat sink 9 is provided. The projection part 7 is provided outside the die pad 5 without being overlapped with the die pad 5 in an upper surface view, and a distance between the die pad 5 and the projection part 7 is larger than a thickness of the grease 8.SELECTED DRAWING: Figure 1

Description

This disclosure relates to semiconductor devices and power conversion devices.

In a fully molded semiconductor device, the semiconductor element is bonded to a die pad extending from a lead frame using a bonding material. The semiconductor element and the lead frame are then electrically connected by wire bonds. Each component in the semiconductor device is sealed and insulated with molding resin to prevent short circuits.

The semiconductor device mounted on the board is connected to a heat sink via grease to dissipate heat. Therefore, heat generated by the semiconductor element passes from the semiconductor element through the bonding material, die pad, mold resin, and grease, and is dissipated from the heat sink to the outside. In this heat dissipation path, the mold resin has a lower thermal conductivity than other materials, so it is likely to affect the thermal resistance from the semiconductor element to the heat sink.

For example, Patent Document 1 discloses a device that enhances heat dissipation by exposing the back surface of the die pad from the mold resin.

JP 2010-50323 A

However, with the technology described in Patent Document 1, the interface between the mold resin and the grease is located at a position that overlaps with the die pad when viewed from above, that is, inside the die pad, so there is a problem in that it is not possible to ensure an insulation distance.

The present disclosure therefore aims to provide a technology that can improve heat dissipation in a semiconductor device while maintaining insulation.

The semiconductor device according to the present disclosure comprises a lead frame including a die pad, a semiconductor element mounted on one side of the die pad, a molded resin that seals the semiconductor element and the lead frame with the other side of the die pad opposite to the one side exposed, and a heat sink arranged via grease on the one side of the molded resin where the other side of the die pad is exposed, the one side of the molded resin where the other side of the die pad is exposed has a protrusion whose tip abuts against the heat sink, the protrusion is arranged outside the die pad in a top view so as not to overlap the die pad, and the distance between the die pad and the protrusion is greater than the thickness of the grease.

According to the present disclosure, the die pad can be exposed from the molded resin and the die pad and heat sink can be connected via grease with the protrusions ensuring the required thickness, thereby improving heat dissipation. Furthermore, when viewed from above, the interface between the molded resin and the grease is located outside the die pad, ensuring an insulation distance.

As a result, it is possible to improve heat dissipation while maintaining insulation in a semiconductor device.

1 is a cross-sectional view of a semiconductor device according to a first embodiment; 4 is a cross-sectional view of a molding die during molding of the semiconductor device according to the first embodiment. FIG. 1 is a bottom view of a semiconductor device according to a first embodiment; FIG. 11 is a bottom view of a semiconductor device according to a second embodiment. FIG. 11 is a cross-sectional view of a semiconductor device according to a third embodiment. FIG. 13 is a cross-sectional view of a semiconductor device according to a fourth embodiment. FIG. 13 is a bottom view of a semiconductor device according to a fourth embodiment. 13 is a cross-sectional view of a molding die during molding of a semiconductor device according to a fourth embodiment. FIG. 13 is a block diagram showing a configuration of a power conversion system to which a power conversion device according to a fifth embodiment is applied. FIG. FIG. 1 is a cross-sectional view of a semiconductor device according to a related technique.

<First embodiment>
<Configuration of Semiconductor Device>
First Embodiment A first embodiment will be described below with reference to the drawings. Fig. 1 is a cross-sectional view of a semiconductor device 100 according to a first embodiment.

As shown in FIG. 1, the semiconductor device 100 includes a lead frame 3, a semiconductor element 1, a molded resin 6, and a heat sink 9.

The lead frame 3 includes a die pad 5, a first lead 3b, and a second lead 3a.

The die pad 5 is formed in a plate shape. When viewed from above, the die pad 5 is formed in a rectangular shape. The die pad 5 is connected to the first lead 3b.

The second lead 3a is disposed on the opposite side of the die pad 5 to the first lead 3b. Specifically, in FIG. 1, the first lead 3b is disposed on the right side of the die pad 5, and the second lead 3a is disposed on the left side of the die pad 5. The material of the lead frame 3 is, for example, copper (Cu).

The semiconductor element 1 is bonded to one surface of the die pad 5 by a bonding material 2. The bonding material 2 is conductive and has high high-temperature reliability, such as lead-free solder or sintered paste containing silver (Ag), so that the material does not melt at high temperatures of around 175°C.

The lead frame 3 is made of copper (Cu) and is plated with silver (Ag) or the like to increase the bonding strength with the bonding material 2, but this is not shown in FIG. 1.

The semiconductor element 1 is an element that functions as, for example, a switching element or a rectifying element. The switching element is, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The rectifying element is a diode element.

The material constituting the semiconductor element 1 is, for example, silicon (Si). Note that the material constituting the semiconductor element 1 is not limited to silicon, and may be, for example, a wide band gap semiconductor material such as silicon carbide (SiC), gallium nitride (GaN), or diamond (C). A wide band gap semiconductor material is a material that has a band gap wider than that of silicon. A semiconductor element 1 made of a wide band gap semiconductor material is capable of operating using a large current and in a high temperature environment. For this reason, it is preferable that the material constituting the semiconductor element 1 is a wide band gap semiconductor material.

The semiconductor element 1 is electrically connected to the second lead 3a and the first lead 3b by wires 4a and 4b, respectively.

The wires 4a and 4b are made of copper (Cu) or aluminum (Al), which have high electrical conductivity. Ultrasonic bonding is used to connect the wires 4a and 4b.

The molded resin 6 seals the semiconductor element 1 and the lead frame 3, leaving the back surface, which is the other side of the die pad 5 opposite the front surface, the tip side of the second lead 3a, and the tip side of the first lead 3b exposed.

The heat sink 9 is placed on the bottom surface of the molded resin 6, which is the surface on which the back surface of the die pad 5 is exposed, via grease 8.

In addition, the bottom surface of the molded resin 6, where the back surface of the die pad 5 is exposed, is provided with six protrusions 7 whose tips abut against the heat sink 9.

Here, we will briefly explain the method for forming the protrusion 7. Figure 2 is a cross-sectional view of the molding die 10 during molding of the semiconductor device 100 according to the first embodiment.

After the semiconductor element 1 is joined to the die pad 5 of the lead frame 3 and wire-bonded, it is insulated and sealed in a molding die 10 by a thermosetting molding resin 6, as shown in FIG. 2. The molding die 10 is composed of an upper die 10a and a lower die 10b, and six grooves 11 are provided on the bottom surface of the lower die 10b. Six protrusions 7 are formed by injecting molding resin 6 into the six grooves 11. Each groove 11 has a truncated cone shape to make it easy to remove after molding. When the molding resin 6 is injected into the molding die 10, the die pad 5 is pressed against the bottom surface of the lower die 10b.

Next, the protrusion 7 will be described. Figure 3 is a bottom view of the semiconductor device 100 according to the first embodiment.

As shown in FIG. 3, the six protrusions 7 are provided outside the die pad 5 in a top view so as not to overlap with the die pad 5. Specifically, the protrusions 7 are arranged three on each of the left and right sides of the die pad 5, and are spaced apart in the front-to-rear direction.

As shown in FIG. 1, grease 8 is applied between the semiconductor device 100 and the heat sink 9 to fill the gap between the semiconductor device 100 and the heat sink 9. The grease 8 is applied to a thickness equal to the distance from the bottom surface of the molded resin 6 to the tip of each protrusion 7.

The molded resin 6 and the heat sink 9 are connected so that the tip of each protrusion 7 abuts against the heat sink 9. This connection allows the thickness of the grease 8 to be kept constant. A screw fastening method is used to connect the molded resin 6 and the heat sink 9. The molded resin 6 and the heat sink 9 are fastened with screws by inserting screws (not shown) through screw holes 12a, 12b extending in the vertical direction provided on the front and rear sides of the molded resin 6.

<Comparison with related technologies>
Next, a comparison between the first embodiment and the related art will be described below. Fig. 10 is a cross-sectional view of a semiconductor device 101 according to the related art.

As shown in FIG. 10, the semiconductor device 101 according to the related art is a fully molded semiconductor device, and differs from the semiconductor device 100 according to the first embodiment in that it does not have a protrusion 7 and that the back surface of the die pad 5 is not exposed from the mold resin 6.

Although not shown, in related technology, the mold resin 6 is injected while the die pad 5 is suspended within the lower mold 10b. In this case, the flow of the mold resin 6 causes the die pad 5 to deform in the vertical direction. The deformation of the die pad 5 causes the distance from the semiconductor element 1 to the heat sink 9 to vary, resulting in unstable heat dissipation.

In contrast, in the first embodiment, the mold resin 6 is injected while the die pad 5 is pressed against the bottom surface of the lower mold 10b, so the flow of the mold resin 6 does not cause the die pad 5 to deform in the vertical direction. As a result, the distance from the semiconductor element 1 to the heat sink 9 is constant, and heat dissipation is stable.

In addition, in the related technology, the heat dissipation path from the semiconductor element 1 to the heat sink 9 is the semiconductor element 1, the bonding material 2, the die pad 5, the molded resin 6, the grease 8, and the heat sink 9.

In contrast, in the first embodiment, the heat dissipation path from the semiconductor element 1 to the heat sink 9 does not have a layer of molded resin 6, as compared to the related art. Since molded resin 6 has the lowest thermal conductivity of all the materials in the heat dissipation path, the elimination of the layer of molded resin 6 in the heat dissipation path significantly improves heat dissipation.

Normally, when the die pad 5 is exposed from the mold resin 6, the mold resin 6 that acts as an insulator between the semiconductor element 1 and the heat sink 9 is no longer present when the semiconductor element 1 is energized, which can cause a short circuit.

In the first embodiment, the insulating role played by the molded resin 6 is replaced by grease 8. Grease 8 also has insulating properties, but in related technology, when the molded resin 6 is screwed to the heat sink 9, the thickness of the grease 8 becomes thin, and the insulating properties decrease. In addition, in the first embodiment, when screwing, the protrusions 7 function as spacers, making it possible to maintain the parallelism of the molded resin 6 and the heat sink 9.

Furthermore, in the related art, even if the thickness of the grease 8 is ensured when the screw is fastened, it is possible that the thickness may become thin while the semiconductor device is in operation. In some cases, the die pad 5 is exposed from the molded resin 6, and an insulating sheet is placed instead of the grease 8. Even when an insulating sheet is used, it is expected that the thickness of the insulating sheet may become uneven or thin due to the screw fastening, making the heat dissipation and insulation unstable. In contrast, in the first embodiment, as described above, there is an effect of keeping the thickness of the grease 8 constant.

＜Effects＞
As described above, in the first embodiment, the semiconductor device 100 includes the lead frame 3 including the die pad 5, the semiconductor element 1 mounted on the back surface of the die pad 5, the molded resin 6 that seals the semiconductor element 1 and the lead frame 3 with the back surface opposite to the front surface of the die pad 5 exposed, and the heat sink 9 that is disposed via grease 8 on the bottom surface of the molded resin 6 where the back surface of the die pad 5 is exposed. The bottom surface of the molded resin 6 where the back surface of the die pad 5 is exposed is provided with a protrusion 7 whose tip abuts against the heat sink 9, and the protrusion 7 is provided outside the die pad 5 so as not to overlap with the die pad 5 in a top view, and the distance between the die pad 5 and the protrusion 7 is greater than the thickness of the grease 8.

As a result, the die pad 5 can be exposed from the molded resin 6, and the die pad 5 and the heat sink 9 can be connected via the grease 8 with the necessary thickness ensured by the protrusions 7, improving heat dissipation. Furthermore, in top view, the interface between the molded resin 6 and the grease 8 is located outside the die pad 5, ensuring an insulation distance.

As a result, the semiconductor device 100 can improve heat dissipation while maintaining insulation.

<Embodiment 2>
Next, a semiconductor device 100 according to a second embodiment will be described. Fig. 4 is a bottom view of the semiconductor device 100 according to the second embodiment. Note that in the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

In the first embodiment, six protrusions 7 are provided, whereas in the second embodiment, as shown in FIG. 4, four protrusions 7 are provided. Specifically, the protrusions 7 are arranged two on each of the left and right sides of the die pad 5, and are spaced apart in the front-to-rear direction.

In the first embodiment, six protrusions 7 are provided to suppress bending when the molded resin 6 is screwed to the heat sink 9. However, depending on the size or shape of the molded resin 6, the bending when screwed may be small. In this case, the number of protrusions 7 can be reduced to four.

As described above, in the second embodiment, by reducing the number of protrusions 7 to four, it is possible to reduce the amount of molded resin 6 and simplify the manufacturing process compared to the first embodiment.

<Third embodiment>
Next, a semiconductor device 100 according to a third embodiment will be described. Fig. 5 is a cross-sectional view of the semiconductor device 100 according to the third embodiment. Note that in the third embodiment, the same components as those described in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 5, the third embodiment differs from the first embodiment in that the heat sink 9 has six recesses 13 that fit into the six protrusions 7, respectively.

The six recesses 13 are provided at locations facing the six protrusions on the heat sink 9. Each recess 13 is set to a depth such that when fitted with each protrusion 7, the thickness of the grease 8 does not become thinner than in the first embodiment. When attaching the molded resin 6 to the heat sink 9, the six protrusions 7 are fitted into the six recesses 13, respectively, and then screwed in place. The number of recesses 13 can be changed to match the number of protrusions 7. For example, when recesses 13 are provided in the heat sink 9 of the second embodiment, four recesses 13 are provided.

As described above, in the third embodiment, the heat sink 9 is provided with a recess 13 that fits with the protrusion 7. This allows the molded resin 6 and the heat sink 9 to be positioned easily and accurately.

Furthermore, by fitting the protrusion 7 and the recess 13, misalignment can be suppressed. Since misalignment can be suppressed, the torque required for screwing the molded resin 6 to the heat sink 9 can be reduced compared to the first embodiment. In the semiconductor device 100, warping occurs due to the difference in the linear expansion coefficient between the molded resin 6 and the lead frame 3, and the molded resin 6 and the components sealed therein may be destroyed by the bending load applied during screwing. In the third embodiment, the torque required for screwing can be reduced, making the above-mentioned bending destruction less likely to occur.

In addition, when the semiconductor device 100 operates at high temperatures, thermal stress also occurs between the molded resin 6 and the lead frame 3. The thermal stress causes peeling between the molded resin 6 and the lead frame 3, and moisture is absorbed from this area, which causes a short circuit. In the third embodiment, as described above, the screw torque can be reduced, thereby reducing the risk of a short circuit.

<Fourth embodiment>
Next, a semiconductor device 100 according to a fourth embodiment will be described. Fig. 6 is a cross-sectional view of the semiconductor device 100 according to the fourth embodiment. Fig. 7 is a bottom view of the semiconductor device 100 according to the fourth embodiment. Fig. 8 is a cross-sectional view of the molding die 10 when molding the semiconductor device 100 according to the fourth embodiment. Note that in the fourth embodiment, the same components as those described in the first to third embodiments are given the same reference numerals and descriptions thereof will be omitted.

As shown in Figures 6 and 7, the fourth embodiment differs from the first embodiment in that, instead of the six protrusions 7, a step portion 14 is provided whose tip abuts against the heat sink 9.

The step portion 14 is provided on the bottom surface of the molded resin 6 where the back surface of the die pad 5 is exposed, surrounding the periphery of the die pad 5 and being located outside the die pad 5 so as not to overlap with the die pad 5 in a top view. Specifically, the step portion 14 is provided across the outer edge of the bottom surface of the molded resin 6 where the back surface of the die pad 5 is exposed. In addition, the distance between the die pad 5 and the step portion 14 is greater than the thickness of the grease 8.

As shown in FIG. 8, the bottom surface of the lower die 10b is provided with a groove 15 that is shaped like a rectangular frame when viewed from above. A step 14 is formed by injecting molding resin 6 into the groove 15. When the molding resin 6 is injected into the molding die 10, the die pad 5 is pressed against the bottom surface of the lower die 10b.

As shown in FIG. 6, grease 8 is applied between the molded resin 6 and the heat sink 9, and the molded resin 6 is screwed to the heat sink 9, as in the first embodiment. At this time, the step 14 formed by the molded resin 6 allows the thickness of the grease 8 to be kept constant.

As described above, in the fourth embodiment, the semiconductor device 100 includes a lead frame 3 including a die pad 5, a semiconductor element 1 mounted on the front surface of the die pad 5, a molded resin 6 that seals the semiconductor element 1 and the lead frame 3 with the rear surface opposite to the front surface of the die pad 5 exposed, and a heat sink 9 that is disposed via grease 8 on the bottom surface of the molded resin 6 where the rear surface of the die pad 5 is exposed. The bottom surface of the molded resin 6 where the rear surface of the die pad 5 is exposed has a step portion 14 whose tip abuts against the heat sink 9 and surrounds the periphery of the die pad 5, and the step portion 14 is disposed outside the die pad 5 in a top view so as not to overlap with the die pad 5, and the distance between the die pad 5 and the step portion 14 is greater than the thickness of the grease 8.

Therefore, the same effect as in the first embodiment can be obtained. Furthermore, since the step portion 14 surrounds the periphery of the die pad 5, it is possible to prevent the grease 8 from leaking and spreading outside the step portion 14 when viewed from above after the die pad 5 and the heat sink 9 are connected.

The semiconductor device 100 may be used in a machine or device that generates vibration. In the first embodiment, when the grease 8 spreads to the outside due to vibration, a gap is formed between the mold resin 6 and the heat sink 9. The gap prevents the heat generated by the semiconductor element 1 from being efficiently transferred to the heat sink 9, and the heat dissipation performance may be reduced. Furthermore, in the first embodiment, since the grease 8 plays an insulating role, when a gap is formed, partial discharge may occur there. In contrast, in the fourth embodiment, as described above, after the die pad 5 and the heat sink 9 are connected, the step portion 14 can prevent the grease 8 from leaking and spreading to the outside of the step portion 14 when viewed from above, so that it is possible to suppress the reduction in heat dissipation performance and the occurrence of partial discharge.

<Fifth embodiment>
In this embodiment, the semiconductor device 100 according to the above-mentioned first to fourth embodiments is applied to a power conversion device 200. Although the application of the semiconductor device 100 according to the first to fourth embodiments is not limited to a specific power conversion device, hereinafter, as a fifth embodiment, a case where the semiconductor device 100 according to the first to fourth embodiments is applied to a three-phase inverter will be described.

Figure 9 is a block diagram showing the configuration of a power conversion system that uses a power conversion device 200 according to embodiment 5.

The power conversion system shown in FIG. 9 is composed of a power source 400, a power conversion device 200, and a load 300. The power source 400 is a DC power source and supplies DC power to the power conversion device 200. The power source 400 can be composed of various things, for example, a DC system, a solar cell, or a storage battery, or it may be composed of a rectifier circuit connected to an AC system or an AC/DC converter. The power source 400 may also be composed of a DC/DC converter that converts the DC power output from the DC system into a specified power.

The power conversion device 200 is a three-phase inverter connected between the power source 400 and the load 300, converts DC power supplied from the power source 400 into AC power, and supplies the AC power to the load 300. As shown in FIG. 9, the power conversion device 200 includes a main conversion circuit 201 that converts DC power into AC power and outputs it, and a control circuit 203 that outputs a control signal to the main conversion circuit 201 to control the main conversion circuit 201.

The load 300 is a three-phase motor driven by AC power supplied from the power conversion device 200. Note that the load 300 is not limited to a specific use, but is a motor mounted on various electrical devices, and is used, for example, as a motor for hybrid cars, electric cars, railroad cars, elevators, or air conditioning equipment.

The power conversion device 200 will be described in detail below. The main conversion circuit 201 includes a switching element (not shown) and a freewheeling diode (not shown), and the switching element switches to convert the DC power supplied from the power source 400 into AC power, which is then supplied to the load 300. There are various specific circuit configurations for the main conversion circuit 201, but the main conversion circuit 201 according to this embodiment is a two-level three-phase full bridge circuit, and can be configured from six switching elements and six freewheeling diodes connected in inverse parallel to each switching element.

At least one of the switching elements and free wheel diodes of the main conversion circuit 201 is configured with a semiconductor device 100 corresponding to either of the above-mentioned embodiments 1 or 2. In embodiment 5, as an example, the main conversion circuit 201 includes the semiconductor device 100 according to embodiment 1. The six switching elements are connected in series with two switching elements to configure upper and lower arms, and each upper and lower arm configures each phase (U phase, V phase, W phase) of the full bridge circuit. The output terminals of each upper and lower arm, i.e., the three output terminals of the main conversion circuit 201, are connected to the load 300.

The main conversion circuit 201 also includes a drive circuit (not shown) for driving each switching element, but the drive circuit may be built into the semiconductor device 100, or may be configured to include a drive circuit separate from the semiconductor device 100. The drive circuit generates a drive signal for driving the switching element of the main conversion circuit 201 and supplies it to the control electrode of the switching element of the main conversion circuit 201. Specifically, in accordance with a control signal from the control circuit 203 described later, a drive signal for turning the switching element on and a drive signal for turning the switching element off are output to the control electrode of each switching element. When the switching element is maintained in the on state, the drive signal is a voltage signal (on signal) equal to or higher than the threshold voltage of the switching element, and when the switching element is maintained in the off state, the drive signal is a voltage signal (off signal) equal to or lower than the threshold voltage of the switching element.

The control circuit 203 controls the switching elements of the main conversion circuit 201 so that the desired power is supplied to the load 300. Specifically, the time (on time) that each switching element of the main conversion circuit 201 should be in the on state is calculated based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control that modulates the on time of the switching elements according to the voltage to be output. Then, a control command (control signal) is output to the drive circuit provided in the main conversion circuit 201 so that an on signal is output to the switching element that should be in the on state at each point in time, and an off signal is output to the switching element that should be in the off state. The drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element according to this control signal.

In the power conversion device 200 according to this embodiment, the semiconductor device 100 is used as the switching element and free wheel diode of the main conversion circuit 201, so that insulation can be ensured and heat dissipation can be improved.

In this embodiment, an example in which the semiconductor device 100 according to the first to fourth embodiments is applied to a two-level three-phase inverter has been described, but the application of the semiconductor device 100 according to the first to fourth embodiments is not limited to this, and the semiconductor device 100 can be applied to various power conversion devices. In this embodiment, a two-level power conversion device is described, but a three-level or multi-level power conversion device may also be used, and when power is supplied to a single-phase load, the semiconductor device 100 according to the first to fourth embodiments may be applied to a single-phase inverter. Also, when power is supplied to a DC load, etc., the semiconductor device 100 according to the first to fourth embodiments can also be applied to a DC/DC converter or an AC/DC converter.

In addition, the power conversion device 200 to which the semiconductor device 100 according to the first to fourth embodiments is applied is not limited to the case where the load described above is an electric motor, but can also be used, for example, as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a non-contact power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

The embodiments can be freely combined, modified, or omitted as appropriate.

Various aspects of this disclosure are summarized below as appendices.

(Appendix 1)
a lead frame including a die pad;
a semiconductor element mounted on one surface of the die pad;
a molding resin that seals the semiconductor element and the lead frame in a state where the other surface of the die pad opposite to the one surface is exposed;
a heat sink disposed on one surface of the mold resin on which the other surface of the die pad is exposed, with grease interposed therebetween;
a protrusion having a tip end that abuts against the heat sink is provided on the one surface of the molding resin from which the other surface of the die pad is exposed,
the protrusion is provided outside the die pad so as not to overlap the die pad when viewed from above,
a distance between the die pad and the protrusion is greater than a thickness of the grease.

(Appendix 2)
2. The semiconductor device according to claim 1, wherein the heat sink has a recess that fits with the protrusion.

(Appendix 3)
a lead frame including a die pad;
a semiconductor element mounted on one surface of the die pad;
a molding resin that seals the semiconductor element and the lead frame in a state where the other surface of the die pad opposite to the one surface is exposed;
a heat sink disposed on one surface of the mold resin on which the other surface of the die pad is exposed, with grease interposed therebetween;
a step portion having a tip end that abuts against the heat sink and that surrounds a periphery of the die pad is provided on the one surface of the molding resin from which the other surface of the die pad is exposed;
the step portion is provided outside the die pad so as not to overlap with the die pad in a top view,
a distance between the die pad and the step portion is greater than a thickness of the grease.

(Appendix 4)
A main conversion circuit having the semiconductor device according to claim 1, which converts input power and outputs the converted power;
a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit;
A power conversion device comprising:

(Appendix 5)
A main conversion circuit having the semiconductor device according to claim 3, which converts input power and outputs the converted power;
a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit;
A power conversion device comprising:

1 semiconductor element, 3 lead frame, 5 die pad, 6 molded resin, 7 protrusion, 8 grease, 9 heat sink, 14 step, 100 semiconductor device, 200 power conversion device, 201 main conversion circuit, 203 control circuit.

Claims (5)

a lead frame including a die pad;
a semiconductor element mounted on one surface of the die pad;
a molding resin that seals the semiconductor element and the lead frame in a state where the other surface of the die pad opposite to the one surface is exposed;
a heat sink disposed on one surface of the mold resin on which the other surface of the die pad is exposed, with grease interposed therebetween;
a protrusion having a tip end that abuts against the heat sink is provided on the one surface of the molding resin from which the other surface of the die pad is exposed,
the protrusion is provided outside the die pad so as not to overlap the die pad when viewed from above,
a distance between the die pad and the protrusion is greater than a thickness of the grease. The semiconductor device according to claim 1, wherein the heat sink has a recess that fits into the protrusion. a lead frame including a die pad;
a semiconductor element mounted on one surface of the die pad;
a molding resin that seals the semiconductor element and the lead frame in a state where the other surface of the die pad opposite to the one surface is exposed;
a heat sink disposed on one surface of the mold resin on which the other surface of the die pad is exposed, with grease interposed therebetween;
a step portion having a tip end that abuts against the heat sink and that surrounds a periphery of the die pad is provided on the one surface of the molding resin from which the other surface of the die pad is exposed;
the step portion is provided outside the die pad so as not to overlap with the die pad in a top view,
a distance between the die pad and the step portion is greater than a thickness of the grease. a main conversion circuit having the semiconductor device according to claim 1, which converts input power and outputs the converted power;
a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit;
A power conversion device comprising: a main conversion circuit having the semiconductor device according to claim 3, which converts input power and outputs the converted power;
a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit;
A power conversion device comprising:

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