(Extracted from wipo)
Patent application title: SEMICONDUCTOR DEVICE AND POWER CONVERTER HAVING THE SAME
Technical field
[0001]
　The present invention relates to a semiconductor device and a power conversion device including the same, and more particularly to a double-sided heat dissipation semiconductor device sealed entirely with a mold resin.
Background art
[0002]
　A semiconductor device for power includes semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal-Oxide-Semiconductor field-effect transistors), IC chips, LSI chips, and the like after die bonding to lead frames for external terminals. The electrodes and the external terminals are electrically connected with wires or inner leads to input / output signals from / to the outside.
[0003]
　In the resin mold type semiconductor device, in the molding process, the surface (mounting surface) of the lead frame on which the semiconductor element is mounted and the heat radiation surface on the opposite side are sealed with mold resin. Since a power semiconductor device includes a high heat generating element therein, the mold resin is required to have high heat dissipation.
[0004]
　Conventionally, as a resin mold type semiconductor device, the mounting surface side of the lead frame is sealed with a low stress resin used as a mold resin for a general integrated circuit, and the heat dissipation side mainly uses alumina filler. Is sealed with a high heat dissipation resin of 3 W / m • K or more. Moreover, in patent document 1, in the power converter device provided with the motor and the inverter, one surface of the power module of the inverter is in contact with the metal casing of the motor or the inverter, and the other surface is in contact with the metal plate for heat dissipation. The heat generated by the power module is released from both sides.
Prior art documents
Patent Literature
[0005]
Patent Document 1: Japanese Patent No. 5946962
Summary of the Invention
Problems to be solved by the invention
[0006]
　In some conventional semiconductor devices, the heat dissipation surface side of the lead frame is sealed with a high heat dissipation resin. However, from the viewpoint of improving heat dissipation, it is desirable to cover the mounting surface side with a high heat dissipation resin. However, since the high heat dissipation resin is expensive, it is not practical from the viewpoint of cost to cover all regions including the mounting surface with the high heat dissipation resin.
[0007]
　In Patent Document 1, a metal plate for heat dissipation is brought into contact with a thin power module having a resin thickness of about 300 μm from both sides, and the creeping distance from the metal plate to the lead frame is short. For this reason, it is expected that the withstand voltage is low, and there is a high possibility that an insulation failure will occur. In order to increase the creepage distance, it is necessary to reduce the area of the metal plate or increase the thickness of the resin.
[0008]
　In the case of a semiconductor device having a total resin thickness of 300 μm, for example, if the semiconductor element is 100 μm and the lead frame is 100 μm, the thickness of the resin on the heat radiating surface side is less than 100 μm. In order to improve heat dissipation, it is necessary to make the resin thinner. However, when thin molding with a thickness of less than 100 μm is performed in the molding process, there is a problem that voids or unfilled resin are likely to occur and become defective.
[0009]
　SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to obtain a low-cost semiconductor device that secures a creepage distance and is excellent in heat dissipation and insulation in a double-sided heat dissipation semiconductor device using two types of resins. .
Means for solving the problem
[0010]
　A semiconductor device according to the present invention includes a lead frame on which a semiconductor element is mounted, an inner lead connected to an electrode of the semiconductor element, a part of the lead frame, the semiconductor element, and the inner lead. And a second resin. When the surface of the lead frame on which the semiconductor element is mounted is the mounting surface, and the surface opposite to the mounting surface is the heat dissipation surface, a frame-shaped protrusion is provided on the outer peripheral end of the heat dissipation surface, and the frame-shaped protrusion faces The two thin sides and the first thin molded portion that covers between the two sides are integrally molded with the second resin, and the other two opposite sides of the frame-shaped protrusion are molded with the first resin. On the mounting surface, an element sealing portion that covers a part of the inner lead and the semiconductor element is formed of the first resin, and the inner lead exposed from a part of the surface of the element sealing portion and the element sealing portion A second thin-walled molded portion that covers and is molded with the second resin.
The invention's effect
[0011]
　According to the present invention, by providing the frame-like projections on the heat radiating surface of the lead frame, the creepage distance is increased with a small increase in resin, and the insulation is improved. In addition, the two opposite sides of the frame-shaped projection and the first thin-walled molded part are integrally molded with the second resin, and the other two opposite sides are molded with the first resin, thereby Compared with the case where all four sides are molded at once with the second resin, the fluidity of the second resin to the first thin molded portion is improved, and the second resin is easily wetted. For this reason, the adhesion between the first thin molded part and the lead frame is high, and peeling and chipping of the first thin molded part are unlikely to occur. Furthermore, by covering the inner lead with the second thin molded part, the heat generated in the semiconductor element can be efficiently released from both the first thin molded part and the second thin molded part. For these reasons, according to the present invention, a highly reliable semiconductor device having excellent heat dissipation and insulation can be obtained at low cost.
　Other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention with reference to the drawings.
Brief Description of Drawings
[0012]
FIG. 1 is a cross-sectional view showing a semiconductor device according to a first embodiment of the present invention.
2 is a cross-sectional view showing the semiconductor device after the first transfer molding step in the first embodiment of the present invention. FIG.
FIG. 3 is a plan view of the semiconductor device after the first transfer molding process according to the first embodiment of the present invention as viewed from the heat radiating surface side.
FIG. 4 is a plan view of the semiconductor device after the second transfer molding process according to the first embodiment of the present invention as viewed from the heat radiating surface side.
FIG. 5 is a cross-sectional view showing a first transfer molding step of the semiconductor device according to the first embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a second transfer molding step of the semiconductor device according to the first embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a first compression molding step of the semiconductor device according to the first embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a state where a heat sink is arranged in the semiconductor device according to the first embodiment of the present invention.
FIG. 9 is a cross-sectional view showing an electric motor including the semiconductor device according to the first embodiment of the present invention.
FIG. 10 is a cross-sectional view showing another electric motor including the semiconductor device according to the first embodiment of the present invention.
FIG. 11 is a cross-sectional view showing a semiconductor device according to a second embodiment of the present invention.
FIG. 12 is a plan view of the semiconductor device after the first transfer molding process according to the second embodiment of the present invention as viewed from the mounting surface side.
FIG. 13 is a plan view of the semiconductor device with the inner leads exposed from the mounting surface side after the first molding step in the second embodiment of the present invention.
FIG. 14 is a plan view of the semiconductor device after the second transfer molding process according to the second embodiment of the present invention as viewed from the mounting surface side.
FIG. 15 is a cross-sectional view showing a semiconductor device according to a third embodiment of the present invention.
FIG. 16 is a plan view of the semiconductor device after the second transfer molding process according to the third embodiment of the present invention, viewed from the heat radiating surface side.
FIG. 17 is a cross-sectional view showing a surface state of a surface roughened inner lead in Embodiment 4 of the present invention.
FIG. 18 is a plan view showing a scaly portion of a laser roughened inner lead in the fifth embodiment of the present invention.
FIG. 19 is a top perspective view showing a scaly portion of the laser roughened inner lead in the fifth embodiment of the present invention.
FIG. 20 is a sectional view showing a semiconductor device according to a sixth embodiment of the present invention.
FIG. 21 is a sectional view showing a second transfer molding step of the semiconductor device according to the sixth embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0013]
Embodiment 1 FIG.
　The semiconductor device according to the first embodiment of the present invention will be described below based on the drawings. FIG. 1 is a cross-sectional view showing a configuration of a resin mold type semiconductor device according to the first embodiment, FIG. 2 is a cross-sectional view showing the semiconductor device after the first transfer molding process, and FIG. FIG. 4 is a plan view of the semiconductor device after the transfer molding process as viewed from the heat dissipation surface, and FIG. 4 is a plan view of the semiconductor device after the second transfer molding process as viewed from the heat dissipation surface. In the drawings, the same or corresponding parts are denoted by the same reference numerals.
[0014]
　The semiconductor device 100 according to the first embodiment is a double-sided heat dissipation semiconductor device sealed with two kinds of resins. As shown in FIG. 1, a semiconductor device 100 includes a lead frame 2 on which a semiconductor element 1 is mounted, an external terminal 4, wires 5 and inner leads 6 connected to electrodes of the semiconductor element 1, and a first resin. One mold resin 7 and a second mold resin 8 that is a second resin are included.
[0015]
　In the following description, the surface of the lead frame 2 on which the semiconductor element 1 is mounted is referred to as a mounting surface 2a, and the surface opposite to the mounting surface 2a is referred to as a heat dissipation surface 2b. In the example shown in FIG. 1, the upper surface of the lead frame 2 is the mounting surface 2a, and the lower surface is the heat dissipation surface 2b. A semiconductor element 1 such as an IGBT, MOSFET, IC chip, or LSI chip is mounted on the mounting surface 2a via a bonding member 3 such as solder or silver. The lead frame 2 is a copper plate or a copper alloy plate, and the surface thereof is coated with metal plating (not shown) such as gold, silver, nickel, tin or the like.
[0016]
　The electrode pad of the semiconductor element 1 is electrically connected to the external terminal 4 via the wire 5 connected by wire bonding, or the inner lead 6 made of a copper plate or copper alloy plate material, and the signal input to the outside is made. Output. The wire 5 and the inner lead 6 can be replaced with each other. The wire 5 is made of gold, silver, aluminum, copper or the like, and the wire diameter is about 20 μm to 500 μm.
[0017]
　A part of the lead frame 2, the semiconductor element 1, the wire 5, and the inner lead 6 are sealed with a first mold resin 7 and a second mold resin 8. Each of the first mold resin 7 and the second mold resin 8 is a thermosetting epoxy resin or the like. However, a high heat radiation resin having a higher thermal conductivity than the first mold resin 7 is mainly used for the second mold resin 8 that covers the heat radiation surface 2b. The thermal conductivity of the second mold resin 8 is 2 W / m • K to 12 W / m • K. Further, as the first mold resin 7 mainly covering the mounting surface 2a, a low stress resin which is a mold resin of a general integrated circuit is used.
[0018]
　On the outer peripheral end of the heat radiating surface 2b, there is provided a radiating surface side skirt portion, which is a frame-shaped protrusion having a thickness of about 0.3 mm to 2 mm formed by the first mold resin 7 and the second mold resin 8. Yes. The two opposite sides of the radiating surface side skirt portion and the first thin molded portion 8b covering between the two sides are integrally molded by the second mold resin 8, and the other two opposite sides are the first side. Molded with a mold resin 7.
[0019]
　Specifically, as shown in FIG. 4, the radiating surface side skirt portion includes a first skirt portion 7 a formed by the first mold resin 7 and a second skirt portion formed by the second mold resin 8. It consists of a skirt portion 8a. The first skirt portion 7a and the second skirt portion 8a have a rectangular, square, or trapezoidal cross-sectional shape cut in a direction orthogonal to each side. In addition, the corner | angular part of the said cross-sectional shape may be roundish, or the said cross-sectional shape may be circular arc shape.
[0020]
　A first thin molded portion 8b having a thickness of about 0.02 mm to 0.3 mm is integrally formed with the second skirt portion 8a by the second mold resin 8 between the second skirt portions 8a. ing. The first skirt portion 7 a and the second skirt portion 8 a are joined by four resin joint portions 9.
[0021]
　On the other hand, an element sealing portion 7 b that covers a part of the inner lead 6 and the semiconductor element 1 is formed on the mounting surface 2 a by the first mold resin 7. As shown in FIG. 2, the element sealing portion 7b has an upper surface 7c that is a plane parallel to the mounting surface 2a, and four side surfaces orthogonal to the upper surface 7c. However, the upper surface 7c and the four side surfaces of the element sealing portion 7b are not necessarily orthogonal to each other. The inner lead 6 has an end surface 6a parallel to the upper surface 7c of the element sealing portion 7b. The upper surface 7c of the element sealing portion 7b and the end surface 6a of the inner lead 6 are formed to have the same height from the mounting surface 2a.
[0022]
　Further, a second thin molded portion 8 c that covers a part of the surface of the element sealing portion 7 b and the inner lead 6 exposed from the element sealing portion 7 b is formed by the second mold resin 8. In the example shown in FIG. 1, the second thin molded portion 8c covers the upper surface 7c of the element sealing portion 7b, the end surface 6a of the inner lead 6, and one side surface orthogonal to the upper surface 7c of the element sealing portion 7b. Yes.
[0023]
　A molding process of the semiconductor device 100 will be described with reference to FIGS. The semiconductor device 100 is manufactured including two transfer molding steps, FIG. 5 shows the first transfer molding step, and FIG. 6 shows the second transfer molding step. The semiconductor device shown in FIG. 6 is a cross-sectional view at a position indicated by AA in FIG.
[0024]
　As shown in FIG. 5, in the first transfer molding process, the first mold resin 7 melted by the heat and pressure applied by the first molding die 20 passes through the upper gate 22 and the lead frame 2 is installed. The cavity 21 is injected. The first mold resin 7 flows to the mounting surface 2a side of the lead frame 2, fills the cavity 21 to form the element sealing portion 7b, and a cavity (not shown) corresponding to the first skirt portion 7a. ) To form the first skirt portion 7a.
[0025]
　When the first molding die 20 shown in FIG. 5 is used, the end surface 6 a of the inner lead 6 is covered with the first molding resin 7 after the first transfer molding process. For this reason, the first mold resin 7 is shaved by mechanical grinding or laser irradiation or the like in a subsequent process to expose the end face 6 a of the inner lead 6.
[0026]
　On the mounting surface 2a of the lead frame 2 after the first transfer molding process and the post-process, as shown in FIG. 2, an element sealing portion 7b for sealing the semiconductor element 1 with the first mold resin 7 is molded. The end face 6a of the inner lead 6 is exposed from the element sealing portion 7b. Further, as shown in FIG. 3, a first skirt portion 7 a that is two sides parallel to the upper gate 22 is formed on the heat radiating surface 2 b by the first molding resin 7.
[0027]
　Subsequently, a second transfer molding step is performed. In order to improve the adhesion between the first mold resin 7 and the second mold resin 8, the first mold resin 7 may be subjected to UV treatment, plasma treatment or laser treatment after the first transfer molding step. Good. As shown in FIG. 6, the lead frame 2 that has completed the first transfer molding step is installed inside the second molding die 30.
[0028]
　Inside the second molding die 30 in which the lead frame 2 is installed, a cavity 31a corresponding to the second thin molded portion 8c is formed above the element sealing portion 7b molded by the first mold resin 7. Have. Further, on the heat radiating surface 2b side of the lead frame 2, a cavity 31b corresponding to the first thin molded portion 8b and a cavity 31c corresponding to the second skirt portion 8a are provided.
[0029]
　The second mold resin 8 melted by the heat and pressure applied by the second molding die 30 flows through the cavity 31c near the lower gate 32 and flows into the cavity 31b. At this time, since the second mold resin 8 once accumulates in the cavity 31c near the lower gate 32, it can flow uniformly into the cavity 31b. The second mold resin 8 that has passed through the cavity 31b further flows into the cavity 31c on the opposite side farthest from the lower gate 32 serving as the final filling portion. At this time, the second mold resin 8 is hardened and has a high viscosity, but the cavity 31c, which is the final filling portion, has a larger thickness and a smaller flow resistance than the cavity 31b. Is easy to flow.
[0030]
　The second mold resin 8 flows between the upper surface 7c of the element sealing portion 7b formed by the first mold resin 7 and the second molding die 30 simultaneously with the flow into the cavities 31b and 31c. It flows into the cavity 31a. The thickness of the second thin molded portion 8c may be about twice as thick as the first thin molded portion 8b in consideration of the fluidity and heat dissipation of the resin. The thickness of the element sealing portion 7b is at least 0.4 mm or more, and the thickness of the second thin molded portion 8c is added thereto, whereby the insulation on the mounting surface 2a side can be ensured. In the second transfer molding process, the second molding resin 8 is used to mold the second skirt portion 8a, the first thin molded portion 8b, and the second thin molded portion 8c. Take out the molded product.
[0031]
　As shown in FIG. 4, on the heat radiating surface 2b after the second transfer molding process, the second skirt portion 8a having two sides including the side closest to the lower gate 32, and the first covering the space between the two sides. The thin molded portion 8b is integrally molded by the second mold resin 8. In the first embodiment, the first skirt portion 7a formed by the first mold resin 7 is located on the long side, and the second skirt portion 8a formed by the second mold resin 8 is Although it is located on the short side, it may be reversed depending on the position of the gate of the molding die used.
[0032]
　In the first transfer molding process, by performing compression molding, a molded product in which the end surface 6a of the inner lead 6 is exposed from the element sealing portion 7b can be manufactured. As shown in FIG. 7, a thermoplastic fluororesin film 42 having a thickness of about 40 μm to 200 μm is previously adsorbed on the inner surface of the compression molding die 40. This film 42 prevents the molten first mold resin 7 from entering the movable part of the molding die 40.
[0033]
　The upper part of the molding die 40 is a movable part, moves in the direction of arrow A, and stops at a predetermined position on the upper surface of the inner lead 6 while pressurizing the cavity 41. In the cavity 41 inside the molding die 40, the granular first mold resin 7 may be installed in advance, or a normal tablet-like resin for transfer is injected from the upper gate 22 and flows into the cavity 41. You may make it do.
[0034]
　In order to expose the end face 6a of the inner lead 6 using the first molding die 20 shown in FIG. 5, it is necessary to bring the first molding die 20 and the inner lead 6 into contact with each other. However, since the height after mounting of the semiconductor element 1 and the inner lead 6 varies, if the height after mounting is higher than the reference value, the semiconductor element 1 may be stressed and destroyed. When it is low, a gap is formed between the first molding die 20 and the inner lead 6, so that a resin burr of the first molding resin 7 is generated.
[0035]
　On the other hand, in compression molding, the film 42 previously set in the molding die 40 is pressed and thinned to absorb the variation in the height of the semiconductor element 1 and the inner lead 6. Since the gap with the inner lead 6 is filled, no resin burr is generated and the end surface 6a of the inner lead 6 can be exposed.
[0036]
　As described above, by forming the radiating surface side skirt portion through the two transfer molding steps, the fluidity of the second mold resin 8 to the first thin molded portion 8b is improved. 7 and the lead frame 2 are easily wetted and adhesion is improved.
[0037]
　As a comparative example of the first embodiment, a case will be described in which all four sides of the radiating surface side skirt portion and the first thin molded portion are simultaneously molded in one transfer molding step. In the molding die, the thickness of the radiating surface side skirt is larger than that of the first thin molding part, and the flow resistance is smaller. Therefore, the molten resin flows first on the four sides of the radiating surface side skirt, and the first thin molding is performed. The part becomes the final filling part.
[0038]
　In the final filling portion, since the resin that has been hardened and has a high viscosity flows, it is difficult to uniformly flow to the first thin molded portion having a high flow resistance. Also, a weld line is formed because the resin that has flowed to the four sides of the radiating surface side skirt portion first merges at the first thin-walled molded portion, and molded in two transfer molding steps as in the first embodiment Compared to the above, the strength and insulation of the first thin molded part are inferior.
[0039]
　Semiconductor device 100 according to the first embodiment is used in a power conversion device including an inverter that converts electric power and a motor that converts electric energy into mechanical energy. For example, in an in-vehicle application, the motor and the inverter are integrated into an electric motor inverter. At that time, as shown in FIG. 8, the heat radiating surface heat radiating plate 50a and the mounting surface heat radiating plate 50b come into contact with the semiconductor device 100 via heat radiating grease (not shown). The heat radiating surface heat radiating plate 50a is sized to fit within the frame of the heat radiating surface side skirt. The heat radiating surface heat radiating plate 50a and the mounting surface heat radiating plate 50b are integrated with an inverter housing or a motor housing having a large heat capacity, or are joined to these housings by screwing or the like.
[0040]
　9 and 10 show an electric motor including the semiconductor device 100 according to the first embodiment. The electric motors 400 and 401 shown in FIGS. 9 and 10 may be any of an integrated unit of an electric power steering motor and an inverter, a mild hybrid ISG (Integrated Starter Generator), and an integrated unit of a strong hybrid motor and an inverter. . The motors 300 and 301 have a stator and a rotor arranged inside a metal casing, and the inverters 200 and 201 have a motor drive circuit.
[0041]
　In the electric motor 400 shown in FIG. 9, the motor 300 and the inverter 200 are integrated, and the heat radiating surface heat radiating plate 50 a and the mounting surface heat radiating plate 50 b are integrated with the casing of the inverter 200. In the electric motor 401 shown in FIG. 10, the motor 301 and the inverter 201 are integrated, the heat radiation surface heat sink 50 a is integrated with the housing of the motor 301, and the mounting surface heat sink 50 b is integrated with the housing of the inverter 201. Yes. In contrast to the example shown in FIG. 10, the mounting surface heat radiating plate 50 b may be integrated with the housing of the motor 301, and the heat radiating surface heat radiating plate 50 a may be integrated with the housing of the inverter 201. Further, the heat radiating plate and the housing may be separated, and may be brought into contact with each other via heat radiating grease or the like, and the heat radiating plate may be fixed to the housing by screwing.
[0042]
　In the first embodiment, the surface of the lead frame 2 is coated with a metal plating such as gold, silver, nickel, tin or the like, but may not be coated. Moreover, although the lead frame 2 has a uniform thickness, a lead frame having a partially different thickness may be used (however, the cost increases in this case). The surface of the inner lead 6 is not coated with metal plating, but may be coated.
[0043]
　In the first embodiment, the upper surface 7c of the element sealing portion 7b and one side surface closest to the lower gate 32 are covered with the second mold resin 8, but the arrangement of the second mold resin 8 is as follows. It is not limited to this. Since the second mold resin 8 which is a high heat dissipation resin is expensive, the arrangement may be determined in consideration of heat dissipation and cost.
[0044]
　According to the first embodiment, by providing the radiating surface side skirt portion on the radiating surface 2b of the lead frame 2, the strength of the outer peripheral end portion of the lead frame 2 to which the high pressure of resin molding is applied can be ensured, A small amount of resin increases the creepage distance and improves insulation. Therefore, the semiconductor device 100 according to the first embodiment is suitable as a power module using an IGBT as the semiconductor element 1 and having a withstand voltage of 600 V or more.
[0045]
　Further, the first skirt portion 7a is molded by the first mold resin 7, and the second skirt portion 8a and the first thin-wall molded portion 8b are integrally molded by the second mold resin 8, thereby dissipating heat. Compared to the case where all the four sides of the surface side skirt portion are molded at once with the second mold resin 8, the fluidity of the second mold resin 8 is improved and wetted with respect to the lead frame 2 and the first mold resin 7. It becomes easy and adhesion improves. For this reason, the adhesion between the first thin molded portion 8b and the lead frame 2 is increased, and the first thin molded portion 8b is less likely to be peeled off or chipped.
[0046]
　Further, by covering the end face 6a of the inner lead 6 with the second thin molded portion 8c, the heat generated in the semiconductor element 1 can be efficiently transmitted from both the first thin molded portion 8b and the second thin molded portion 8c. It can be missed and heat dissipation is improved. In addition, since only the second thin molded portion 8c is molded with the second mold resin 8 on the mounting surface 2a side, heat dissipation is improved while suppressing the amount of expensive high heat dissipation resin used. Can do. For these reasons, according to the first embodiment, a highly reliable semiconductor device 100 having excellent heat dissipation and insulation can be obtained at low cost.
[0047]
Embodiment 2. FIG.
　FIG. 11 is a cross-sectional view showing the configuration of the semiconductor device according to the second embodiment of the present invention. FIG. 12 is a plan view of the semiconductor device after the first transfer molding process viewed from the mounting surface side, and FIG. 13 shows the semiconductor device with the inner leads exposed from the mounting surface side after the first molding process. FIG. 14 is a plan view of the semiconductor device after the second transfer molding process, as viewed from the mounting surface side.
[0048]
　For example, in the case of a semiconductor device that requires a withstand voltage of 600 V or more equipped with a strong hybrid IGBT, it is necessary to ensure a creepage distance longer than usual (for example, 1.8 mm or more). Increasing the thickness of the element sealing portion 7b increases the creepage distance, but increases the module size, increases the amount of resin used, and increases the cost. In response to such a problem, the creepage distance can be increased at low cost by providing a frame-like protrusion on the mounting surface 2a side as well as the heat radiating surface 2b side.
[0049]
　In the semiconductor device 101 according to the second embodiment, a mounting surface side skirt portion that is a mounting surface side frame-shaped protrusion having a thickness of about 0.3 mm to 2 mm is provided on the outer peripheral end portion of the upper surface 7c of the element sealing portion 7b. It has been. The two opposite sides of the mounting surface side skirt portion and the second thin molded portion 8c covering the two sides are formed integrally with the second mold resin 8, and the other two opposite facing side skirt portions of the mounting surface side skirt portion are formed. The sides are formed by the first mold resin 7. Since other configurations are the same as those of the semiconductor device 100 according to the first embodiment, description thereof is omitted here.
[0050]
　As shown in FIG. 14, the mounting surface side skirt portion is composed of a third skirt portion 7 d formed by the first mold resin 7 and a fourth skirt portion 8 d formed by the second mold resin 8. Has been. The third skirt portion 7d and the fourth skirt portion 8d have a rectangular, square, or trapezoidal cross-sectional shape cut in a direction orthogonal to their respective sides. In addition, the corner | angular part of the said cross-sectional shape may be roundish, or the said cross-sectional shape may be circular arc shape.
[0051]
　In addition, a second thin molded portion 8c having a thickness of about 0.02 mm to 0.3 mm is integrally formed with the fourth skirt portion 8d by the second mold resin 8 between the fourth skirt portions 8d. Molded. The third skirt portion 7d and the fourth skirt portion 8d are joined by four resin joint portions 9.
[0052]
　A manufacturing process of the semiconductor device 101 according to the second embodiment will be described with reference to FIGS. The semiconductor device 101 is manufactured including two molding steps, and the first transfer molding step similar to that of the first embodiment is performed. However, the internal shape of the molding die is different from that of the first embodiment.
[0053]
　As shown in FIG. 12, on the mounting surface 2a after the first transfer molding step, a third skirt portion 7d that is two sides parallel to the upper gate 22 is formed on the upper surface 7c of the element sealing portion 7b. The molding resin 7 is used. Moreover, the 1st skirt part 7a which is two sides parallel to the upper gate 22 is shape | molded by the 1st mold resin 7 in the thermal radiation surface 2b (refer FIG. 3).
[0054]
　As described in the first embodiment, the inner lead 6 is not exposed in the molded product when the first transfer molding process is the normal transfer molding as shown in FIG. For this reason, it is necessary to expose the inner lead 6 by shaving the first mold resin 7 by mechanical grinding or laser irradiation in a subsequent process. On the other hand, in the molded product when the first transfer molding process is compression molding, the inner lead 6 is exposed as shown in FIG.
[0055]
　Subsequently, a second transfer molding step similar to that in the first embodiment is performed. However, the internal shape of the molding die is different from that of the first embodiment. As shown in FIG. 14, on the mounting surface 2a after the second transfer molding, on the upper surface 7c of the element sealing portion 7b, two fourth skirt portions 8d including the side closest to the lower gate 32, A second thin molded portion 8 c that covers between the two sides is integrally molded with the second mold resin 8. Further, on the heat radiation surface 2b, two second skirt portions 8a including a side closest to the lower gate 32 and a first thin molded portion 8b covering the two sides are provided with the second mold resin 8. (See FIG. 4).
[0056]
　According to the second embodiment, in addition to the same effects as those of the first embodiment, by providing the mounting surface side skirt portion, the creepage distance becomes longer than that of the first embodiment, so that the withstand voltage is further higher. A semiconductor device 101 with double-sided heat dissipation is obtained.
[0057]
Embodiment 3 FIG.
　FIG. 15 is a cross-sectional view showing a semiconductor device according to Embodiment 3 of the present invention, and FIG. 16 is a plan view of the semiconductor device after the second transfer molding process as seen from the heat radiating surface side. FIG. 15 is a cross-sectional view at a position indicated by BB in FIG.
[0058]
　In the first embodiment and the second embodiment, the heat radiating surface side is formed by the first skirt portion 7a formed by the first mold resin 7 and the second skirt portion 8a formed by the second mold resin 8. A skirt was constructed. In such a configuration, when the interface between the first thin molded portion 8b and the first skirt portion 7a formed by the second mold resin 8 is peeled off, the heat radiating surface heat radiating plate 50a (see FIG. 8) and the lead frame The creepage distance between the two is equal to the thickness of the first thin molded portion 8b, and the withstand voltage may be greatly reduced.
[0059]
　For this reason, in the semiconductor device 102 according to the third embodiment, the two opposite sides of the radiating surface side skirt portion formed by the first mold resin 7, that is, the first skirt portion 7 a is used as the second mold resin. 8 is covered with a fifth skirt portion 8e formed by the above method. The fifth skirt portion 8e is formed at the time of the second transfer molding, and covers the inner side surface of the first skirt portion 7a and the lower surface parallel to the heat radiating surface 2b, as shown in FIG.
[0060]
　Thereby, the heat radiation surface 2b side of the semiconductor device 102 covers between the four sides of the heat radiation surface side skirt portion (second skirt portion 8a and fifth skirt portion 8e) and the four sides as shown in FIG. The first thin molded portion 8 b is integrally formed with the second mold resin 8. In addition, in order to make the height of the 2nd skirt part 8a and the 5th skirt part 8e uniform, the height of the 1st skirt part 7a is formed low compared with the said Embodiment 1. FIG.
[0061]
　Further, when the mounting surface side skirt portion is provided as in the semiconductor device 101 according to the second embodiment (see FIG. 14), the second molding resin 8 causes the first molding to occur in the first transfer molding. You may make it shape | mold the 6th skirt part (not shown) which covers the 3rd skirt part 7d shape | molded by the mold resin 7. FIG.
[0062]
　According to the third embodiment, in addition to the same effects as those of the first embodiment, the first skirt portion 7a is covered with the fifth skirt portion 8e, so that the first on the heat radiation surface 2b side due to production variation or the like. Even if the interface between the one thin molded portion 8b and the first skirt portion 7a is peeled off, the semiconductor device 102 can be obtained which can ensure a creepage distance and reduce insulation defects.
[0063]
Embodiment 4 FIG.
　FIG. 17 is a cross-sectional view showing the surface state of the surface roughened inner lead used in the semiconductor device according to the fourth embodiment of the present invention. Note that the overall configuration and the manufacturing method of the semiconductor device according to the fourth embodiment are the same as those of the first embodiment, and a description thereof will be omitted here.
[0064]
　The semiconductor device according to the fourth embodiment replaces the inner lead 6 used in the first embodiment in order to improve the adhesion between the first mold resin 7 and the second mold resin 8 and the inner lead. Further, the surface roughened inner lead 11 is used. The surface roughened inner lead 11 is obtained by chemically or physically roughening the surface of an inner lead made of copper or a copper alloy to a surface roughness Ra of 0.06 to 0.2. Since innumerable irregularities are formed on the surface of the surface-roughened inner lead 11, a high anchor effect can be obtained.
[0065]
　According to the fourth embodiment, in addition to the same effects as those of the first embodiment, the use of the surface-roughened inner lead 11 allows the first mold resin 7 and The adhesion with the second mold resin 8 is improved. Furthermore, since the surface roughened inner lead 11 has a larger surface area than the normal inner lead 6, the heat dissipation is improved.
[0066]
Embodiment 5. FIG.
　18 is a plan view showing a scaly portion of the laser roughened inner lead according to the fifth embodiment of the present invention, and FIG. 19 is a top perspective view of a cross section taken along line CC in FIG. Note that the overall configuration and the manufacturing method of the semiconductor device according to the fifth embodiment are the same as those of the first embodiment, and a description thereof will be omitted here.
[0067]
　The semiconductor device according to the fifth embodiment replaces the inner lead 6 used in the first embodiment in order to improve the adhesion between the first mold resin 7 and the second mold resin 8 and the inner lead. In addition, a laser roughened inner lead 12 is used. The laser-roughened inner lead 12 has a scale-like portion 13 in which the metal constituting the inner lead or the surface of the metal plating covering the surface of the inner lead is deformed into a scale shape. Since the scaly portion 13 has a complicated shape in which scaly projections are continuously arranged and both sides thereof are raised, a high anchor effect can be obtained by disposing the scaly portion 13.
[0068]
　The scaly portion 13 is formed by continuously performing spot irradiation with a laser to melt the metal or metal plating constituting the inner lead and deform it into a scaly shape. The formation of the scale portion 13 with respect to the inner lead can be performed together with, for example, exposing the inner lead by laser irradiation after the first transfer step.
[0069]
　Further, since the scaly portion 13 is formed by laser irradiation, the scaly portion 13 is selectively applied to an arbitrary portion of the inner lead, for example, a portion where stress is easily applied when the semiconductor device is discharged from the molding die and initial peeling is likely to occur. Can be arranged. The width and height of the scaly portion 13 can be adjusted by laser output, scanning speed, and the like. The width of the scaly portion 13 is desirably 60 μm or more, and the adhesion is further improved by increasing the width according to the area of the place where the scaly portion 13 is arranged.
[0070]
　According to the fifth embodiment, in addition to the same effects as those of the first embodiment, by using the laser roughened inner lead 12, the first mold resin 7 and the case where the normal inner lead 6 is used and The adhesion with the second mold resin 8 is improved. Further, since the laser roughened inner lead 12 has a larger surface area than the normal inner lead 6, the heat dissipation can be improved.
[0071]
Embodiment 6 FIG.
　20 is a cross-sectional view showing a semiconductor device according to the sixth embodiment of the present invention, and FIG. 21 is a cross-sectional view showing a second transfer molding process of the semiconductor device according to the sixth embodiment. In the semiconductor device 103 according to the sixth embodiment, the heat radiating surface heat radiating plate 51a and the mounting surface heat radiating plate 51b are respectively connected to the first thin molded portion 8b and the second thin molded portion 8c without using heat radiating grease. It is joined directly. Since other configurations are the same as those of the semiconductor device 100 according to the first embodiment, description thereof is omitted here.
[0072]
　In the sixth embodiment, as shown in FIG. 21, in the second transfer molding process, the heat radiation surface heat radiation plate 51 a and the mounting surface heat radiation plate 51 b are installed inside the molding die 60. Inside the molding die 60, a cavity 62b corresponding to the first thin molded portion 8b is formed between the heat radiating surface 2b of the lead frame 2 and the heat radiating surface heat radiating plate 51a.
[0073]
　In addition, a cavity 62a corresponding to the second thin molded portion 8c is formed between the element sealing portion 7b and the mounting surface heat sink 51b by the movable pin 61 installed inside the molding die 60. Yes. Since the pin 61 is pulled out during molding, the second mold resin 8 flows in the pin hole with a delay, and the pin hole does not open.
[0074]
　Similar to the first embodiment, in the second transfer molding step, the second mold resin 8 causes the second skirt portion 8a and the first thin molded portion 8b to be mounted on the mounting surface 2a. The second thin molded portion 8c is molded. At this time, the second mold resin 8 before curing that has flowed into the cavity 62a and the cavity 62b becomes an adhesive, and the heat radiation surface heat radiation plate 51a is joined to the first thin molded part 8b, and the second thin molded part 8c is joined. The mounting surface heat sink 51b is joined.
[0075]
　According to the sixth embodiment, in addition to the same effects as those of the first embodiment, the first thin molded portion 8b and the second thin molded portion 8c are provided with the heat radiating surface heat radiating plate 51a and the mounting surface heat radiating plate 51b, respectively. Are directly joined, the contact thermal resistance is reduced, and the heat dissipation is further improved. In addition, after the second transfer molding step, the step of joining the heat sink to the first thin molded portion 8b and the second thin molded portion 8c via the thermal grease can be omitted, and no thermal grease is required. Therefore, the material cost can be reduced.
[0076]
　Note that the shape, number, and arrangement of each component of the semiconductor device according to the first to sixth embodiments, such as the semiconductor element 1, the external terminal 4, the wire 5, and the inner lead 6, are particularly limited. It is not a thing and it selects suitably according to the function calculated | required. The present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.
Explanation of symbols
[0077]
　DESCRIPTION OF SYMBOLS 1 Semiconductor element, 2 Lead frame, 2a Mounting surface, 2b Heat radiation surface, 3 Bonding member, 4 External terminal, 5 Wire, 6 Inner lead, 6a End surface, 7 First mold resin, 7a First skirt part, 7b Element Sealing part, 7c upper surface, 7d third skirt part, 8 second mold resin, 8a second skirt part, 8b first thin molded part, 8c second thin molded part, 8d fourth skirt part 8e Fifth skirt part, 9 Resin joint part, 11 Surface roughened inner lead, 12 Laser roughened inner lead, 13 Scale part, 20 First molding die, 21, 31a, 31b, 31c, 41, 62a , 62b cavity, 22 upper gate, 30 second molding die, 32 lower gate, 40, 60 molding die, 42 film, 50a, 51a heat radiation surface heat sink, 50b, 51b mounting surface heat radiation plate, 6 Pin, 100, 101, 102, 103 semiconductor device, 200, 201 inverter, 300 and 301 motor, 400 and 401 electric motor
The scope of the claims
[Claim 1]
　A lead frame on which a semiconductor element is mounted; an inner lead connected to an electrode of the semiconductor element; a first resin sealing a part of the lead frame and the semiconductor element and the inner lead; and a second resin A semiconductor device provided with a resin,
wherein a surface on the side of the lead frame on which the semiconductor element is mounted is a mounting surface, and a surface opposite to the mounting surface is a
heat dissipation surface. Are provided with a frame-shaped projection, and the two opposite sides of the frame-shaped projection and the first thin molded portion covering the two sides are integrally molded with the second resin, The other two opposite sides are formed of the first resin
, and an element sealing portion that covers a part of the inner lead and the semiconductor element is formed of the first resin on the mounting surface. , A part of the surface of the element sealing portion and Wherein a the second thin-wall portion for covering said inner lead exposed from serial element sealing portion is formed by said second resin.
[Claim 2]
　2. The semiconductor device according to claim 1, wherein two sides of the frame-shaped protrusion formed of the first resin are covered with the second resin.
[Claim 3]
　The element sealing portion has a plane parallel to the mounting surface, and a mounting surface side frame-like projection is provided at an outer peripheral end of the plane, and the two sides facing the mounting surface side frame-like projection and the two sides The second thin-walled molded part covering the space is molded integrally with the second resin, and the other two opposite sides of the mounting surface side frame-shaped protrusion are molded with the first resin. The semiconductor device according to claim 1, wherein:
[Claim 4]
　4. The semiconductor device according to claim 3, wherein two sides of the mounting surface side frame-shaped protrusion formed of the first resin are covered with the second resin. 5.
[Claim 5]
　The element sealing portion has a plane parallel to the mounting surface, and the inner lead has an end surface parallel to the plane, and the plane and the end surface have the same height from the mounting surface. The semiconductor device according to claim 1, wherein:
[Claim 6]
　The semiconductor device according to claim 5, wherein the second thin molded portion covers the flat surface of the element sealing portion and the end surface of the inner lead exposed from the flat surface.
[Claim 7]
　The semiconductor device according to claim 1, wherein a surface of the inner lead is roughened.
[Claim 8]
　The semiconductor device according to claim 1, wherein the inner lead has a scale-like portion in which scale-like protrusions are continuously arranged.
[Claim 9]
　9. The semiconductor device according to claim 1, wherein the second resin is a high heat dissipation resin having a thermal conductivity higher than that of the first resin.
[Claim 10]
　10. The semiconductor device according to claim 1, further comprising a heat dissipation plate that is directly bonded to the first thin molded portion and the second thin molded portion. 11.
[Claim 11]
　A power conversion device including an inverter including one or more semiconductor devices according to any one of claims 1 to 9 and a motor
, wherein the first thin molded portion of the semiconductor device and the motor A power converter, wherein a heat sink is disposed in the second thin molded portion, and each of the heat sinks is a part of a casing of the inverter or the motor.
[Claim 12]
　A power conversion device including an inverter including one or more semiconductor devices according to any one of claims 1 to 9 and a motor
, wherein the first thin molded portion of the semiconductor device and the motor A power converter, wherein a heat sink is disposed in the second thin molded part, and each of the heat sinks is joined to a housing of the inverter or the motor.