Semiconductor device, combination structure for main body part and lead part of semiconductor device, and power conversion apparatus

Abstract

To provide a semiconductor device in which bending deformation caused by an external force hardly occurs in a lead electrode protruding outside and a defect caused by bending of the lead structure during assembly or transportation is reduced, and a power conversion apparatus with the same.SOLUTION: A semiconductor device 1 comprises a semiconductor chip 10, a base electrode 20 supporting the semiconductor chip 10 from a lower side, a lead electrode 30 disposed at an upper side of the semiconductor chip 10, a first connection layer 40, a second connection layer 50, and a sealing member 60. The lead electrode 30 includes a header part 31 opposed to a top face of the semiconductor chip 10 and a lead part 32 extending upward from the header part 31 and protruding to the outside of the sealing member 60, and the lead part 32 is provided in a separate structure in which the lead part is coupled to the header part 31 from a state where the lead part is separated from the header part 31 and the lead electrode 30 is formed. A power conversion apparatus comprises the semiconductor device 1 or is formed by a combination structure of a main body part and the lead part 32 of the semiconductor device 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semiconductor device having lead electrodes provided in a separated structure, a combined structure of a body and lead portions of the semiconductor device, and a power converter including the same. [Background technology]

[0002] Automobiles are equipped with an alternator that generates alternating current using engine power. The alternating current generated by the alternator is converted to direct current by a rectifying element so that it can be used to charge the battery. Conversion to direct current is generally performed by a diode. Semiconductor devices that function as diodes are assembled in groups of six or twelve and attached to a diode holder that is integrated with a heat sink.

[0003] A semiconductor device that functions as a diode for an alternator is packaged in a cylindrical shape or the like. A semiconductor chip that functions as a rectifying element is mounted on a disk-shaped base electrode made of copper or aluminum. A pin-shaped lead electrode is provided above the semiconductor chip so as to protrude upward from the package. The tip of the lead electrode is connected to a terminal of a diode holder.

[0004] Conventionally, various techniques have been proposed for the lead electrodes of such semiconductor devices and their surrounding structures.

[0005] Patent Document 1 describes a semiconductor device including a metal container, a semiconductor chip fixed to the bottom of the metal container, leads fixed to the semiconductor chip via an adhesive layer, and a protective layer covering the exposed surfaces of the leads and the semiconductor chip. In this semiconductor device, the leads are provided in a shape having a header portion that spreads out like a plate in a direction perpendicular to the extension direction of the leads themselves.

[0006] Patent Document 2 describes a wiring structure for checking the operation of a semiconductor device, and a semiconductor device having such a wiring structure. The wiring structure includes a semiconductor device body, a lead wire, a connection part whose surface opposite to the surface to which the lead wire is connected is bonded to the outer surface of the semiconductor device body, and wiring. At least a portion of the wiring is formed on the outer surface of the semiconductor device body, one end of which is connected to a wiring layer in the semiconductor device body, and the other end of which is connected to the connection part. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 9-139462 [Patent Document 2] JP 2010-272764 A Summary of the Invention [Problem to be solved by the invention]

[0008] A semiconductor device that functions as a diode for an alternator has a pin-shaped lead electrode that is columnar and protrudes outward from the device on the opposite side of the base electrode. Such a lead electrode is prone to bending deformation, i.e., curving as a whole, when an external force is applied. A semiconductor device having a lead electrode that protrudes outward has a problem in that defects occur due to bending deformation of the lead electrode due to contact with a jig or the like during assembly, or contact or impact between the lead electrodes during transportation.

[0009] Lead electrodes may be provided in various different lengths according to the distance from the external terminal. The length of the lead electrode protruding outward is usually about 10 mm. However, it may be provided to be about 20 mm or more. When the lead electrode is long, bending deformation due to external forces occurs frequently. The longer the lead electrode is, the more likely it is that it will interfere with jigs used in assembling the semiconductor device, or that it will collide with each other during bulk transportation.

[0010] In the technology described in Patent Document 1, the lead electrode is provided in a shape having a header portion. Such a lead electrode is excellent in dissipating heat during operation of the semiconductor chip. However, with such a shape, there is a concern that an external force applied to the lead electrode may affect the electrical connection between the header portion and the semiconductor chip. There is a demand for a technology that can reduce bending deformation of the lead electrode even when the lead electrode has a header portion.

[0011] In the technology described in Patent Document 2, a connection part is provided and the outer surface of the semiconductor device is exposed to form wiring. This type of structure is provided during measurements to check the operation, but it is difficult to use it in products after shipment. The width of the wiring connected between the wiring layer and the connection part is 5 μm or less, which is different from the electrical structure provided in the product.

[0012] Therefore, an object of the present invention is to provide a semiconductor device in which the lead electrodes protruding outward are less likely to bend and deform due to external forces, thereby reducing defects due to bending of the lead electrodes during assembly or transportation, a combined structure of the main body and lead portions of the semiconductor device, and a power conversion device equipped with the same. [Means for solving the problem]

[0013] In order to solve the above problems, the semiconductor device according to the present invention includes a semiconductor chip, a base electrode supporting the semiconductor chip from below, a lead electrode disposed above the semiconductor chip, a first connection layer electrically connecting the semiconductor chip and the base electrode, a second connection layer electrically connecting the semiconductor chip and the lead electrode, and a sealing member sealing the semiconductor chip, the lead electrode, the first connection layer, and the second connection layer, the lead electrode having a header portion facing the upper surface of the semiconductor chip and a lead portion extending upward from the header portion and protruding to the outside of the sealing member, the lead portion being provided in a separation structure that is connected to the header portion after being separated from the header portion to form the lead electrode. Also, the semiconductor device is formed by a combination structure of a main body portion and a lead portion of a semiconductor device provided in a separation structure that forms a semiconductor device having a lead electrode protruding to the outside. Also, the power conversion device according to the present invention includes the semiconductor device, or is formed by a combination structure of a main body portion and a lead portion of the semiconductor device. Effect of the Invention

[0014] According to the present invention, it is possible to provide a semiconductor device in which the lead electrodes protruding outward are less likely to bend and deform due to external forces, thereby reducing defects due to bending of the lead electrodes during assembly or transportation, a combined structure of a main body and lead portions of the semiconductor device, and a power conversion device equipped with the same. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing a configuration of a semiconductor device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view showing a configuration of a conventional semiconductor device. [Diagram 3] 4A to 4C are cross-sectional views showing examples of connection methods for lead electrodes. [Figure 4] 4A to 4C are cross-sectional views showing examples of connection methods for lead electrodes. [Diagram 5] 4A to 4C are cross-sectional views showing examples of connection methods for lead electrodes. [Figure 6]4A to 4C are cross-sectional views showing examples of connection methods for lead electrodes. [Figure 7] 10A and 10B are cross-sectional views showing an example of a method for attaching a body portion of a semiconductor device to a lead portion. [Figure 8] 10A and 10B are cross-sectional views showing an example of a method for attaching a body portion of a semiconductor device to a lead portion. [Figure 9] FIG. 2 is a cross-sectional view showing an example of the structure of an alternator. [Figure 10] FIG. 4 is a plan view showing an example of a diode holder provided in the alternator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a semiconductor device according to an embodiment of the present invention, a combined structure of a body and a lead of the semiconductor device, and a power converter including the same will be described with reference to the drawings. Note that the same reference numerals are used to designate the same components in the following drawings, and duplicated descriptions will be omitted. In this specification, the side of the semiconductor device where the base electrode is located is referred to as the lower side, and the side where the lead electrode is located is referred to as the upper side.

[0017] FIG. 1 is a cross-sectional view showing a configuration of a semiconductor device according to an embodiment of the present invention. 1, the semiconductor device 1 according to this embodiment includes a semiconductor chip 10, a base electrode 20, a lead electrode 30, a first connection layer 40, a second connection layer 50, and a sealing member 60. In the semiconductor device 1 according to this embodiment, the lead electrode 30 is formed as a separate body from the main body of the semiconductor device 1, and is provided in a separated structure that can be attached to the main body of the semiconductor device 1.

[0018] The semiconductor device 1 is a device in which a semiconductor chip 10 is packaged in a state in which it can be mounted on an external circuit. The semiconductor device 1 seals and protects the semiconductor chip 10, and also provides internal wiring and terminals for electrically connecting the built-in semiconductor chip 10 to external terminals. The semiconductor device 1 can be mounted on an electric device or the like that forms an external circuit by electrically connecting the base electrode 20 and the lead electrode 30.

[0019] The semiconductor device 1 has a pin-shaped lead electrode 30 having a columnar shape protruding toward the outside of the semiconductor device 1 as one of a pair of electrodes that function as terminals of the semiconductor chip 10. The other electrode has a disk-shaped base electrode 20. This asymmetric structure with a pin on one side makes it possible to efficiently fix the semiconductor device 1 to an electric device or the like and to efficiently dissipate heat from the semiconductor chip 10.

[0020] The semiconductor device 1 can incorporate a semiconductor chip 10 that functions as a rectifying element to form a semiconductor package of the rectifying element. The semiconductor device 1 can be used as a diode for an alternator mounted on an automobile such as a four-wheeled automobile or a two-wheeled automobile. A three-phase full-wave rectifying circuit can be formed by combining a plurality of semiconductor devices 1 that function as rectifying elements.

[0021] The semiconductor chip 10 is formed by circuit elements, wiring, and the like that form a predetermined circuit. The semiconductor chip 10 may be a packaged single circuit element or a packaged semiconductor integrated circuit. The semiconductor chip 10 is disposed on the base electrode 20 via a first connection layer 40. When the semiconductor chip 10 functions as a rectifying element, for example, it may be formed by a PN junction diode.

[0022] The semiconductor chip 10 has terminals on its lower and upper sides for electrical connection to other components. The terminal on the lower side of the semiconductor chip 10 is electrically connected to the base electrode 20 via a first connection layer 40. The terminal on the upper side of the semiconductor chip 10 is electrically connected to the lead electrode 30 via a second connection layer 50.

[0023] The base electrode 20 is an electrode that forms a substrate for mounting the semiconductor chip 10 and the like. The base electrode 20 is provided in a disk shape. The base electrode 20 mounts and supports components such as the semiconductor chip 10, the lead electrodes 30, and the sealing member 60 from below. An example of the material for the base electrode 20 is copper. The base electrode 20 can be formed of nickel-plated copper or the like.

[0024] 1, the base electrode 20 has a base 21 and a pedestal 22. The base 21 is provided as a disk-shaped substrate. The pedestal 22 is formed in the center of the base 21. The pedestal 22 protrudes upward from the upper surface of the base 21, and forms a pedestal-shaped flat surface that is higher than the upper surface of the base 21. The semiconductor chip 10 is disposed on the pedestal 22.

[0025] The pedestal 22 is formed in an inverted truncated cone shape, and is provided so that its width increases from the top surface of the base 21 upward. Such a pedestal 22 can form a heat transfer path with a wide heat transfer area that efficiently dissipates heat during operation of the semiconductor chip 10. In addition, since the shape has a larger width on the upper side, it is possible to prevent the sealing member 60 from peeling off from the base electrode 20 even if an external force, thermal stress, or the like is applied to the sealing member 60.

[0026] The lead electrode 30 is an electrode that constitutes the counter electrode of the base electrode 20. The lead electrode 30 is disposed above the semiconductor chip 10. The lead electrode 30 is provided in the shape of a columnar pin that protrudes toward the upper side of the semiconductor device 1. The lower end of the lead electrode 30 is electrically connected to a terminal on the upper side of the semiconductor chip 10 via the second connection layer 50. The upper end of the lead electrode 30 is electrically connected to an external terminal on which the semiconductor device 1 is mounted. An example of a material for the lead electrode 30 is copper. The lead electrode 30 can be formed of nickel-plated copper or the like.

[0027] 1, the lead electrode 30 has a header portion 31 and a lead portion 32. The header portion 31 is provided in a roughly disk-like shape with a protrusion in the center. The lead portion 32 is provided in a roughly cylindrical shape. The header portion 31 is provided in a shape with a large width and is disposed above the semiconductor chip 10 so as to face the upper surface of the semiconductor chip 10. The lead portion 32 extends upward from the center of the upper surface side of the header portion 31 and protrudes to the outside above the sealing member 60.

[0028] The header portion 31 is provided with a larger diameter than the lead portion 32, and spreads out from the lower end side of the lead portion 32 to the left and right in a direction perpendicular to the extension direction of the lead portion 32. Such a header portion 31 can form a heat transfer path with a wide heat transfer area between the semiconductor chip 10 and the lead portion 32. Therefore, heat generated during operation of the semiconductor chip 10 can be efficiently dissipated to the outside through the lead electrode 30.

[0029] 1, the header portion 31 has a main body portion 31a and a protrusion portion 31b. The main body portion 31a is provided in a disk shape. The protrusion portion 31b is formed in the center of the upper surface of the main body portion 31a. The protrusion portion 31b protrudes upward from the upper surface of the main body portion 31a. The protrusion portion 31b is provided in a rough cylindrical shape having a connection hole in the center of the upper surface.

[0030] The protrusion 31b extends upward from the main body 31a and protrudes above the sealing member 60. A connection hole for attaching the lead 32 can be formed on the upper surface of the protrusion 31b. By providing such a protrusion 31b, it is possible to prevent the material of the sealing member 60 from flowing into the connection hole when the sealing member 60 is formed by potting. The main body 31a can be sealed with the surrounding sealing member 60. Therefore, with this structure, it is possible to properly seal the upper surface side of the header 31 while also ensuring a structure for attaching the lead 32.

[0031] The first connection layer 40 is a layer that electrically connects the components of the semiconductor device 1, and is formed of solder, brazing material, etc. The first connection layer 40 joins the lower surface of the semiconductor chip 10 and the upper surface of the seat 22 of the base electrode 20 to each other, and electrically connects the semiconductor chip 10 and the base electrode 20. Examples of materials for the first connection layer 40 include Pb-Sn eutectic solder and lead-free solder.

[0032] The second connection layer 50 is a layer that electrically connects the components of the semiconductor device 1, and is formed of solder, brazing material, etc. The second connection layer 50 joins the upper surface of the semiconductor chip 10 and the lower surface of the header portion 31 of the lead electrode 30 to each other, and electrically connects the semiconductor chip 10 and the lead electrode 30. Examples of materials for the second connection layer 50 include Pb-Sn eutectic solder and lead-free solder.

[0033] The first connection layer 40 and the second connection layer 50 may be formed of the same material, or may be formed of different materials.

[0034] The sealing member 60 is a member that seals the components of the semiconductor device 1, and is formed of insulating resin. The sealing member 60 covers and seals the components such as the semiconductor chip 10 mounted on the base electrode 20, the header portion 31, the first connection layer 40, and the second connection layer 50 from above. The sealing member 60 protects each component from moisture, dust, light, external forces, and the like. Examples of materials for the sealing member 60 include epoxy resin, silicone resin, and silicone rubber. The sealing member 60 can be formed by potting or transfer molding.

[0035] 1, the semiconductor device 1 is packaged in a roughly cylindrical shape that is circular in plan view, but may be provided so as to have a rectangular, polygonal, or other shape in plan view. When used as a rectifying element, the semiconductor chip 10 may include a PN junction diode or the like, but may also include a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or the like.

[0036] 1, the base electrode 20 is provided in a disk shape, but it may be provided in a cup shape with an outer edge rising upward and a concave recess on the upper surface side. Components such as the semiconductor chip 10 can be housed in the recess of the cup-shaped base electrode and sealed with a sealing member 60. The recess of the cup-shaped base electrode may be provided with a pedestal as shown in FIG.

[0037] In addition, a buffer member may be disposed between the semiconductor chip 10 and the base electrode 20 to reduce the thermal expansion difference between the components. For example, a third connection layer, a buffer member, and a first connection layer 40 may be laminated in this order between the base electrode 20 and the semiconductor chip 10. The third connection layer may be formed of solder, brazing material, or the like. As the buffer member, a member having a linear expansion coefficient between the semiconductor chip 10 and the base electrode 20 may be used. As the buffer member, for example, copper-invar-copper (CIC) or the like may be used.

[0038] The semiconductor chip 10 and the base electrode 20 are made of materials with different linear expansion coefficients. A large difference in thermal expansion may occur due to the heat generated during operation of the semiconductor chip 10 or the heat of the environment in which the semiconductor device 1 is placed. Thermal distortion may cause cracks in the connection layer formed of solder or the like, or gaps between components. In response to this, the provision of a buffer member can reduce deterioration and defects caused by the difference in thermal expansion, improving the reliability of the semiconductor device 1.

[0039] 1, the semiconductor device 1 according to this embodiment includes an attachable lead electrode 30. When mounting the semiconductor device 1, the body of the semiconductor device 1 including the header portion 31 and the lead portion 32 can be prepared separately from each other. The lead portion 32 is an independent structure separated from the body of the semiconductor device 1, and is provided in a separate structure that can be attached to the header portion 31 of the body portion.

[0040] The main body of the semiconductor device 1 is constituted by the disk-shaped portion excluding the lead portion 32, and includes the semiconductor chip 10, the base electrode 20, the first connection layer 40, the second connection layer 50, and the sealing member 60, as well as the header portion 31 of the lead electrode 30. When the lead portion 32 is attached to the main body of the semiconductor device 1, it goes from being separated from the header portion 31 to being connected to the header portion 31, thereby forming an integrated lead electrode 30 with electrical continuity between both ends.

[0041] Fig. 2 is a cross-sectional view showing the configuration of a conventional semiconductor device. Fig. 2 shows an example of a conventional semiconductor device used as a diode for an alternator. In Fig. 2, the symbol L indicates the length of the lead electrode protruding from the sealing member to the outside. As shown in FIG. 2, the conventional semiconductor device 5 includes a semiconductor chip 10, a base electrode 20, a lead electrode 35, a first connection layer 40, a second connection layer 50, a sealing member 60, and the like.

[0042] Unlike the semiconductor device 1 according to this embodiment, the conventional semiconductor device 5 includes a lead electrode 35 that has a non-separated structure protruding outward. In the conventional lead electrode 35, a header portion that faces the upper surface of the semiconductor chip and a lead portion that is a columnar pin protruding outward are integrally formed in advance from a single member.

[0043] The conventional semiconductor device 5 has a problem in that an external force is easily applied to the lead electrodes 35 protruding outward, and the external force is easily bending deformation of the lead electrodes 35. When an external force is applied to the conventional lead electrodes 35 during assembly or transportation of the semiconductor device 5, the tip side of the lead electrodes 35 is bent and deformed so as to tilt sideways.

[0044] For example, when assembling the semiconductor device 5, a jig is used to hold the semiconductor device 5 and the lead electrodes 35 upright. When the semiconductor device 5 comes into contact with such a jig and a load is applied, the lead electrodes 35 may bend. Furthermore, when transporting the semiconductor device 5, a large number of semiconductor devices 5 may be bulk-stacked, and a large number of unpackaged semiconductor devices 5 may be packed in cardboard boxes or the like. In such cases, the lead electrodes 35 may collide with each other during transportation, causing the lead electrodes 35 to bend.

[0045] If the lead electrode 35 is bent, the tip of the lead electrode 35 will be misaligned with respect to the external terminal when the semiconductor device 5 is connected to an external circuit. The misalignment of the tip makes it difficult to weld or solder the lead electrode 35 to the external terminal. This requires a task of straightening the bent lead electrode 35. The conventional lead electrode 35 has a problem in that the shape and structure of the lead electrode 35, which is a non-separable structure, require a lot of man-hours to straighten the lead electrode 35 when mounting the semiconductor device 5.

[0046] Such a problem becomes more prominent as the lead electrode 35 becomes longer. The lead electrode 35 may be provided to a different length depending on the structure of the mounting destination of the semiconductor device 5. The length L of the lead electrode 35 protruding outward from the sealing member is usually about 10 mm. However, when the length L of the protruding outward is set to about 20 to 22 mm or more, the frequency and degree of bending deformation become larger.

[0047] In contrast, the semiconductor device 1 according to this embodiment includes the attachable lead electrodes 30, and therefore, during assembly or transportation of the semiconductor device 1, the lead portions 32 can be handled with the lead portions 32 detached from the header portion 31. On the other hand, during mounting of the semiconductor device 1, the lead portions 32 can be attached to the header portion 31, and the semiconductor chip 10 can be electrically connected to an external terminal.

[0048] Therefore, it is possible to avoid unintentional application of a large external force to the lead electrode 30 during assembly or transportation of the semiconductor device 1, thereby preventing bending deformation of the lead electrode 30. Also, since the lead portion 32 is attached to the header portion 31, the body portion and the lead portion 32 of the semiconductor device 1 can be handled separately before mounting the semiconductor device 1. For example, a mounting method can be used in which the lead portion 32 is previously joined to an external terminal, and the header portion 31 of the body portion of the semiconductor device 1 is coupled to the previously joined lead portion 32.

[0049] Figures 3, 4, 5 and 6 are cross-sectional views showing examples of a coupling method for the lead electrodes. Figures 3, 4, 5 and 6 show examples of a coupling method applicable to the semiconductor device 1 according to this embodiment, in which a lead portion 32 having a separated structure is coupled to a header portion 31 provided on the main body side of the semiconductor device 1. Figures 3, 4, 5 and 6 show an enlarged view of the upper portion of the semiconductor device 1 with other portions omitted.

[0050] Figures 3 and 4 show a method for fitting lead portion 32 to header portion 31. Figure 3 shows a method for fitting lead portion 32 into a hole provided in header portion 31. Figure 4 shows a method for fitting header portion 31 into a hole provided in lead portion 32.

[0051] 5 and 6 show a method for screwing the lead portion 32 and the header portion 31 together. Fig. 5 shows a method for screwing the lead portion 32 into a screw hole provided in the header portion 31. Fig. 6 shows a method for screwing the header portion 31 into a screw hole provided in the lead portion 32.

[0052] 3, 4, 5 and 6, the lead portion 32 provided in the separated structure can be coupled to the header portion 31 by fitting the lead portion 32 and the header portion 31 together or by screwing the lead portion 32 and the header portion 31 together. In the attached-type lead electrode 30, the header portion 31 and the lead portion 32 can be formed of the same material. However, the header portion 31 and the lead portion 32 may be formed of different plating materials or by different plating methods.

[0053] As shown in Fig. 3, when the fitting method is used, the lead portion 32 can be fitted into a hole provided in the header portion 31. The header portion 31 can be provided with a hole 110 into which the lead portion 32 can be fitted. In Fig. 3, the hole 110 is formed in the center of the upper surface of the protrusion portion 31b, in the shape of a cylinder with a smooth inner surface.

[0054] Further, the lead portion 32 may be provided with a portion that fits into the hole 110. In FIG. 3, the lead portion 32 has a main body portion 32a and a fitting shaft portion 32b. The main body portion 32a is provided in a cylindrical shape and forms the main body of the lead portion 32. The fitting shaft portion 32b is formed at the lower end of the lead portion 32. The fitting shaft portion 32b is formed in a cylindrical shape with a smooth outer surface. The fitting shaft portion 32b is provided with a diameter smaller than the main body portion 32a and a diameter slightly larger than the hole 110 or a diameter equal to that of the hole 110.

[0055] 3, the fitting shaft portion 32b of the lead portion 32 is provided so as to be able to fit into a hole 110 of the header portion 31. When assembling or transporting the semiconductor device 1, the lead portion 32 is removed as a separate body, and when mounting the semiconductor device 1, the fitting shaft portion 32b can be fitted into the hole 110. By fitting the lead portion 32 into the header portion 31, an integrated lead electrode 30 having electrical continuity between both ends can be formed.

[0056] As shown in Fig. 4, when the fitting method is used, the header portion 31 can be fitted into a hole provided in the lead portion 32. The lead portion 32 can be provided with a hole 120 into which the header 31 is fitted. In Fig. 4, the hole 120 is formed in the center of the lower surface of the lead portion 32, in a cylindrical shape with a smooth inner surface.

[0057] Header portion 31 may have a portion that fits into hole 120. In Fig. 4, protrusion 31b of header portion 31 is formed in a cylindrical shape with a smooth outer surface. Protrusion 31b has a smaller diameter than lead portion 32 and a slightly larger diameter than hole 120 or a diameter equal to that of hole 120.

[0058] 4, protrusion 31b of header portion 31 is provided so as to be able to fit into hole 120 of lead portion 32. When assembling or transporting semiconductor device 1, lead portion 32 is removed as a separate body, and when mounting semiconductor device 1, protrusion 31b can be fitted into hole 120. By fitting lead portion 32 into header portion 31, an integrated lead electrode 30 having electrical continuity between both ends can be formed.

[0059] When using the fitting method, the lead portion 32 and the header portion 31 may be tightly fitted or intermediately fitted as long as the electrical connection between them is ensured. With a tight fit, the lead portion 32 is less likely to come off the header portion 31, and thus it is possible to prevent the lead portion 32 from falling off or an increase in electrical resistance. On the other hand, with an intermediate fit, the lead portion 32 is easily pulled out, and thus the lead portion 32 and the header portion 31 can be detached freely. If they are detachable, then even after the lead portion 32 is joined to an external terminal, the lead portion 32 and the header portion 31 can be separated to perform maintenance or replacement of the main body of the semiconductor device 1.

[0060] According to such a method of fitting the lead portion 32 and the header portion 31, the header portion 31 and the lead portion 32 can be electrically connected to each other by a structure in which the contact area between them is large and the electrical resistance is small. Also, the integrated lead electrode 30 can be formed by the simple work of fitting the fitting shaft portion 32b and the protrusion portion 31b into the holes 110, 120. Therefore, the user of the semiconductor device 1 can complete the semiconductor device 1 equipped with the lead electrode 30 with few man-hours without the need for special equipment or work.

[0061] In particular, according to the method shown in Fig. 3, since there is no need to form connection holes in the lead portions 32, the strength of the lead portions 32 can be easily ensured. Also, since the protrusions 31b of the header portion 31 can be provided with a large diameter, a heat transfer path with a wide heat transfer area can be formed that efficiently dissipates heat during operation of the semiconductor chip 10. On the other hand, according to the method shown in Fig. 4, when the sealing member 60 is formed by potting, the material of the sealing member 60 does not flow into the connection holes, so clogging of the connection holes can be avoided.

[0062] 3, the diameter of the lead portion 32 is set smaller than the diameter of the protrusion 31b, but the diameter of the lead portion 32 and the diameter and height of the protrusion 31b can be set under appropriate conditions. The fitting shaft portion 32b may be set to the same diameter as the main body portion 32a so as to form a side surface continuous with the main body portion 32a. Also, in FIG. 4, the protrusion 31b is fitted into the hole 120, but a fitting shaft portion protruding upward may be formed on the upper surface of the protrusion 31b, and the fitting shaft portion may be fitted into the hole 120.

[0063] As shown in Fig. 5, when using a screw fastening method, the lead portion 32 can be screwed into a screw hole provided in the header portion 31. The header portion 31 can be provided with a screw hole 130 into which the lead portion 32 can be screwed. In Fig. 5, the screw hole 130 is formed in the center of the upper surface of the protrusion portion 31b, in a cylindrical shape having a screw groove on the inner side surface.

[0064] Further, the lead portion 32 may be provided with a portion that screws into the screw hole 130. In Fig. 5, the lead portion 32 has a main body portion 32a and a male thread portion 32c. The main body portion 32a is provided in a cylindrical shape and forms the main body of the lead portion 32. The male thread portion 32c is formed at the lower end of the lead portion 32. The male thread portion 32c is formed in a cylindrical shape with a screw groove on the side surface.

[0065] 5, the male thread portion 32c of the lead portion 32 is provided so as to be screwable into the screw hole 130 of the header portion 31. When assembling or transporting the semiconductor device 1, the lead portion 32 is removed as a separate body, and when mounting the semiconductor device 1, the male thread portion 32c can be screwed into the screw hole 130. By screwing the lead portion 32 into the header portion 31, an integrated lead electrode 30 having electrical continuity between both ends can be formed.

[0066] As shown in Fig. 6, when using a screw fastening method, the header portion 31 can be screwed into a screw hole provided in the lead portion 32. The lead portion 32 can be provided with a screw hole 140 for screwing the header portion 31. In Fig. 6, the screw hole 140 is formed in the center of the lower surface of the lead portion 32 in a cylindrical shape with a screw groove on the inner side surface.

[0067] Further, the header portion 31 can be provided with a portion that screws into the screw hole 140. In Fig. 6, the header portion 31 has a main body portion 31a and a male thread portion 31c. The main body portion 31a is formed in a cylindrical shape and forms the main body of the lead portion 32. The male thread portion 31c extends upward from the main body portion 31a and protrudes outward beyond the sealing member 60. The male thread portion 31c is formed in a cylindrical shape with a screw groove on the side surface.

[0068] 6, the male thread portion 31c of the header portion 31 is provided so as to be screwable into a screw hole 140 of the lead portion 32. When assembling or transporting the semiconductor device 1, the lead portion 32 is removed as a separate body, and when mounting the semiconductor device 1, the male thread portion 31c can be screwed into the screw hole 140. By screwing the lead portion 32 into the header portion 31, an integrated lead electrode 30 having electrical continuity between both ends can be formed.

[0069] According to such a method of fastening the lead portion 32 and the header portion 31 with screws, the header portion 31 and the lead portion 32 can be detachably coupled to each other. Even after the lead portion 32 is joined to an external terminal or the like, the lead portion 32 and the header portion 31 can be separated to perform maintenance, replacement, etc. of the main body of the semiconductor device 1. In addition, the user of the semiconductor device 1 can easily complete the semiconductor device 1 equipped with the lead electrodes 30 without the need for special equipment or work.

[0070] In particular, according to the method shown in Fig. 5, since there is no need to form a screw hole for connection in the lead portion 32, the strength of the lead portion 32 can be easily ensured. Also, since the protrusion portion 31b of the header portion 31 can be provided with a large diameter, a heat transfer path with a wide heat transfer area can be formed to efficiently dissipate heat during operation of the semiconductor chip 10. On the other hand, according to the method shown in Fig. 6, when the sealing member 60 is formed by potting, the material of the sealing member 60 does not flow into the screw hole for connection, so clogging of the screw hole for connection can be avoided.

[0071] 5, the diameter of the lead portion 32 is set smaller than the diameter of the protrusion 31b, but the diameter of the lead portion 32 and the diameter and height of the protrusion 31b can be set under appropriate conditions. The male thread portion 32c may be set to the same diameter as the main body portion 32a so as to form a side surface continuous with the main body portion 32a. Also, in FIG. 6, the male thread portion 31c is screwed into the screw hole 140, but a male thread portion protruding upward may be formed on the upper surface of the protrusion 31b and the male thread portion may be screwed into the screw hole 140.

[0072] 7 and 8 are cross-sectional views showing an example of a method for mounting the main body of the semiconductor device to the lead portion. Fig. 7 and Fig. 8 show an example of a mounting method that can be used when mounting the semiconductor device 1 according to this embodiment to an external circuit, in which the semiconductor device 1, which is a diode for an alternator, is mounted on a diode holder of the alternator.

[0073] 7 and 8, reference numeral 201 denotes a mounting hole for mounting the semiconductor device 1, and reference numeral 202 denotes a terminal block in which external terminals constituting an external circuit are embedded. The mounting hole 201 is formed so as to penetrate the heat sink of the diode holder from top to bottom. The terminal block 202 is made of epoxy resin or the like, and is installed above the mounting hole 201. The ends of the external terminals are exposed from the terminal block 202 above the centers of the mounting hole 201.

[0074] Fig. 7 shows a state in which the lead portion 32 is joined alone to an external terminal. Fig. 8 shows a state in which a body portion of the semiconductor device 1 having a header portion 31 is attached to the lead portion 32 joined to an external terminal. Fig. 8 shows a state after Fig. 7, and is similar to the state in which the semiconductor device 1 is mounted on an external circuit.

[0075] 7, when mounting the semiconductor device 1, the lead portion 32 separated from the header portion 31 can be joined in advance to an external terminal constituting an external circuit to which the semiconductor device 1 is mounted. The lead portion 32 can be joined to the external terminal by fusion welding such as TIG welding, soldering, or the like. The main body of the semiconductor device 1 including the header portion 31 is prepared separately in a state in which the lead portion 32 is not attached to the header portion 31.

[0076] 8, after the lead portion 32 is joined to an external terminal, the header portion 31 provided in the body portion of the semiconductor device 1 can be coupled to the other end side of the lead portion 32. After the semiconductor device 1 is inserted into a mounting hole 201 for efficient heat dissipation, the lead portion 32 and the header portion 31 are coupled to each other, thereby electrically connecting the semiconductor device 1 to an external terminal.

[0077] The main body of the semiconductor device 1 can be attached to the mounting hole 201 by press-fitting or soldering. When the main body is press-fitted into the mounting hole 201, the side of the semiconductor device 1 may be knurled with a flat or twill pattern. When the main body is soldered to the mounting hole 201, a solder sheet can be interposed between the mounting hole 201 and the semiconductor device 1. The main body can be fixed to the mounting hole 201 by baking or the like with the solder sheet interposed.

[0078] In such an attachment method, the lead portion 32 may be coupled to the header portion 31 by fitting or by screw fastening. When using screw fastening, the body portion of the semiconductor device 1 may be rotated, or a rotating terminal may be provided at the end of the terminal block 202. When the body portion of the semiconductor device 1 is rotated, it is preferable to form a gap between the side surface of the body portion and the inner surface of the attachment hole 201, which is a range of movement of the body portion, without press-fitting the body portion into the attachment hole 201.

[0079] The above-described attachment-type lead electrode 30 can provide a semiconductor device 1 provided in a separation structure in which the lead portion 32 is coupled to the header portion 31 after being separated from the header portion 31 to form the lead electrode 30. Also, a combination structure of the lead portion 32 and the body portion of a semiconductor device provided in a separation structure forming a semiconductor device 1 having a lead electrode 30 protruding outward as an object can be provided, in which the lead portion 32 is coupled to the header portion 31 so as to extend upward from the header portion 31 to form the lead electrode 30 that is the counter electrode of the base electrode 20.

[0080] Therefore, when assembling or transporting the semiconductor device 1, the lead portion 32 can be handled in a state where it is detached from the header portion 31. When assembling or transporting the semiconductor device 1, bending deformation of the lead electrodes 30 caused by application of an external force to the lead electrodes 30 protruding outward is prevented. Therefore, when connecting the semiconductor device 5 to an external circuit, it is possible to prevent the tip side of the lead electrodes 30 from being misaligned with respect to an external terminal, and to prevent variation in the position of the tip side of the lead electrodes 30 for each of the multiple semiconductor devices 1.

[0081] Therefore, by providing a semiconductor device 1 having an attachable lead electrode 30 and a combined structure of the main body and lead portions 32 of the semiconductor device as an object, it is possible to provide a semiconductor device in which the lead electrodes protruding outward are less likely to bend and deform due to external forces, thereby reducing defects due to bending of the lead electrodes during assembly and transportation, a combined structure of the main body and lead portions of the semiconductor device, and a power conversion device equipped with the same.

[0082] The main body of the semiconductor device can be manufactured using a common manufacturing process regardless of the length of the lead portion 32, so that the manufacturing process can be standardized to improve efficiency and a variety of semiconductor devices with different lengths of lead portion 32 can be easily provided. When mounting the semiconductor device 1, the work of straightening the lead electrode 30 that has been bent and deformed is no longer necessary, and poor bonding between the lead electrode 30 and external terminals is reduced, so that a highly reliable semiconductor device 1 and power conversion device can be provided. The terminal portion attached to the semiconductor chip 10 is widely sealed with the sealing member 60, so that the environmental resistance of the semiconductor device 1 and power conversion device can be improved.

[0083] In addition, since the lead portion 32 is provided in a separated structure, different plating methods can be applied to the header portion 31 and the lead portion 32 that are provided in the main body of the semiconductor device. For example, the plating method, such as electrolytic plating and electroless plating, and the plating material can be changed to different types. In the case of a conventional lead electrode having a non-separated structure, TIG welding cannot be performed if electroless plating containing phosphorus is used, but in the case of the lead electrode 30 having a separated structure, such a restriction can be eliminated. If a mounting method is used in which the lead portion 32 is previously joined to an external terminal, the heat and surge generated when welding to the external terminal do not affect the main body, so that restrictions on plating and the influence on the main body of the semiconductor device can be avoided.

[0084] In the semiconductor device 1 having the attached lead electrode 30, or in the combined structure of the main body of the semiconductor device as an object and the lead portion 32, the length of the lead electrode 30 protruding outward from the sealing member is preferably 20 mm or more. The length of the lead electrode protruding outward from the sealing member is more preferably 22 mm or more, even more preferably 24 mm or more, and even more preferably 26 mm or more. With such a length, the lead electrode 30 having a separated structure is more effective because bending deformation is likely to occur if the lead electrode 30 has a non-separated structure.

[0085] Fig. 9 is a cross-sectional view showing an example of the structure of an alternator. Fig. 10 is a plan view showing an example of a diode holder provided in the alternator. Figs. 9 and 10 illustrate the structure of an alternator as an example of a power conversion device including the semiconductor device 1 according to this embodiment. The alternator shown in Fig. 9 is provided with the diode holder shown in Fig. 10.

[0086] The semiconductor device 1 and the combined structure of the body and lead of the semiconductor device can be provided in a power conversion device. The alternator 200 is a device that generates AC power. The alternator 200 is provided with a rectifier that converts the generated AC power into DC power. The alternator 200 is mounted on an automobile or the like and generates AC power using the power of the engine. The generated AC power is then converted into DC power, and the DC power is output to a battery or the like for charging.

[0087] As shown in FIG. 9, the alternator 200 includes a rotor 210, a stator 211, a front frame 221, a rear frame 222, a diode holder 230, a brush 241, an IC regulator 242, a protective cover 243, a slip ring 244, a field winding 245, a rotor core 246, a pulley 247, a shaft 248, and an output terminal 249.

[0088] A shaft 248 is coupled to the rotor 210. The stator 211 is supported by a front frame 221 and a rear frame 222. The shaft 248 is mechanically connected to the engine of the vehicle via a pulley 247, and is inserted into the center of the stator 211. The shaft 248 is rotated by the rotation of the engine of the vehicle. An excitation current is passed through the field winding 245 via the brushes 241 and the slip rings 244. The rotor core 246 is excited by the passage of current through the field winding 245.

[0089] When shaft 248 rotates, rotor 210 rotates inside stator 211, and AC power is generated by electromagnetic induction. The AC power generated by rotor 210 and stator 211 is converted to DC power by rectifier elements 233 and 234 mounted on diode holder 230, and then output from output terminal 249 to an electric device, a battery, or the like.

[0090] As shown in Fig. 10, the diode holder 230 includes heat sinks 231 and 232, rectifying elements 233 and 234, and an element terminal 236. The rectifying elements 233 and 234 include a plurality of normal rectifying elements 233 and a plurality of reverse rectifying elements 234. In Fig. 9, six normal rectifying elements 233 and six reverse rectifying elements 234 are included.

[0091] The semiconductor device 1 described above can be used as each of the rectifying elements 233 and 234. By changing the polarity of the semiconductor chip 10, forward and reverse diodes can be formed. The semiconductor device 1 is inserted and fixed in mounting holes formed in the heat sinks 231 and 232, respectively. The lead electrode 30 of the semiconductor device 1 is electrically connected to an element terminal 236 installed above the mounting hole.

[0092] The heat sinks 231, 232 include a positive heat sink 231 and a negative heat sink 232. The semiconductor device 1, which is a normal diode, is attached to the positive heat sink 231. The semiconductor device 1, which is a reverse diode, is attached to the negative heat sink 232. The heat sinks 231, 232 have the function of dissipating heat generated during operation of the semiconductor device 1. An external element terminal 236 is fixed to the heat sinks 231, 232 so as to be bridged above the mounting holes.

[0093] The positive electrode side heat sink 231 and the negative electrode side heat sink 232 are disposed to be spaced apart from each other and are electrically insulated from each other. As shown in Fig. 9, the normal rectifying element 233 and the reverse rectifying element 234 are electrically connected to each other by a connection terminal 235. The rectifier of the alternator 100 includes, for example, three normal rectifying elements 233 and three reverse rectifying elements 234. The multiple rectifying elements 233, 234 form a three-phase full-wave rectifying circuit.

[0094] In such a power conversion device, the semiconductor device 1 constituting the circuit element has an attachable lead electrode 30, so that the lead portion 32 of the semiconductor device 1 can be joined in advance to the external element terminal 236 constituting the external circuit to which the semiconductor device 1 is mounted. The main body portion of the semiconductor device 1 including the header portion 31 can be coupled to the lead portion 32 joined to the element terminal 236.

[0095] Therefore, when mounting the semiconductor device 1, the main body of the semiconductor device 1 having the header portion 31 and the lead portion 32 can be prepared separately from each other. During assembly or transportation of the semiconductor device 1, the application of unintended large external force to the lead electrode 30 can be avoided, and bending deformation of the lead electrode 30 can be reduced, so that misalignment between the lead electrode 30 and the external element terminal 236 is unlikely to occur. In addition, when the lead portion 32 is previously joined to the external terminal, heat or surges during welding to the external terminal do not affect the main body. Therefore, the semiconductor device 1 can be easily and reliably electrically connected to the external element terminal 236, and a highly reliable power conversion device in which the semiconductor device 1 is mounted can be obtained.

[0096] In a power conversion device to which multiple semiconductor devices 1 are attached, the multiple semiconductor devices 1 and the combined structures of the main bodies and leads of the multiple semiconductor devices can be configured to have different appearances for each type of semiconductor chip. By changing the appearance of the main body of the semiconductor device, the type of semiconductor chip built into the semiconductor device 1 can be identified.

[0097] The appearance of the main body may be the shape, color, texture, and combination of surface members and materials of the main body, etc. As for the appearance of the main body, it is preferable to change the diameter and height of the protrusion 31b of the header part 31, the shape of the protrusion 31b in a plan view, the diameter of the connection hole and the fitting shaft part, the diameter of the male thread part and the screw hole, etc., in order to prevent the function of the main body from being affected.

[0098] For example, in a single power conversion device, the appearances of multiple semiconductor devices 1 and the appearance of the combined structure of the main body and lead portions of multiple semiconductor devices can be made to have a common appearance for each polarity of the diodes of the semiconductor chip 10, and can also be made to have different appearances depending on the polarity of the diodes of the semiconductor chip 10.

[0099] That is, a power conversion device to which multiple semiconductor devices 1 such as alternators are attached can include multiple semiconductor devices 1 with different appearances of their main bodies, or a combination structure of multiple semiconductor devices with different appearances of their main bodies and lead parts. With such a power conversion device, when the lead parts 32 of the semiconductor devices 1 are joined to the element terminals 236 in advance, it is easy to determine which lead parts 32 are to be attached to which body part of which semiconductor device 1 based on their appearance. Therefore, electrical connection between the semiconductor device 1 and the external element terminals 236 can be easily and reliably performed.

[0100] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are included without departing from the technical scope. For example, the above-described embodiments are not necessarily limited to those having all the configurations described. It is also possible to replace a part of the configuration of an embodiment with another configuration, or to add another configuration to the configuration of an embodiment. It is also possible to add another configuration to, delete a configuration, or replace a configuration with respect to a part of the configuration of an embodiment.

[0101] For example, the power converter constitutes a rectifier of an alternator, but the semiconductor device 1 and the combined structure of the body and lead of the semiconductor device may be applied to other power converters. As the power converter, a device to which a large current is applied and to which a semiconductor device having pin-shaped lead electrodes is attached is preferable, and a device having a converter, an inverter, or a combination of these is preferable. [Explanation of symbols]

[0102] 1 Semiconductor device 10. Semiconductor Chips 20 Base Electrode 30 Lead Electrode 31 Header section 31a Main body 31b Protrusion 32 Lead section 32a Main body 32b Fitting shaft part 32c male thread 35 Lead Electrode 40 First connection layer 50 Second connection layer 60 Sealing member 110 holes 120 holes 130 screw hole 140 screw hole 201 Mounting hole 202 Terminal block

Claims

1. A semiconductor chip; a base electrode supporting the semiconductor chip from below; a lead electrode disposed above the semiconductor chip; a first connection layer that electrically connects the semiconductor chip and the base electrode; a second connection layer that electrically connects the semiconductor chip and the lead electrode; a sealing member that seals the semiconductor chip, the lead electrodes, the first connection layer, and the second connection layer, the lead electrode has a header portion facing an upper surface of the semiconductor chip, and a lead portion extending upward from the header portion and protruding to the outside of the sealing member, The lead portion is provided in a separated structure in which the lead portion is separated from the header portion and then coupled to the header portion to form the lead electrode.

2. 2. The semiconductor device according to claim 1, The lead portions are coupled to the header portion by fitting the lead portions to the header portion or by fastening the lead portions to the header portion with screws.

3. 2. The semiconductor device according to claim 1, The header portion has a protrusion that protrudes upward from the center of an upper surface thereof, The lead portion is coupled to the protrusion portion.

4. 2. The semiconductor device according to claim 1, The lead electrode has a length protruding from the sealing member to the outside of the semiconductor device of 20 mm or more.

5. A power conversion device comprising the semiconductor device according to claim 1 .

6. A semiconductor device according to any one of claims 1 to 4, The plurality of semiconductor devices are configured in a combined structure having different appearances for each type of semiconductor chip, forming a power conversion device.

7. A combination structure of a main body and a lead portion of a semiconductor device provided in an isolation structure forming a semiconductor device having a lead electrode protruding outward, the device main body comprises a semiconductor chip, a base electrode supporting the semiconductor chip from below, a header portion facing an upper surface of the semiconductor chip, a first connection layer electrically connecting the semiconductor chip and the base electrode, a second connection layer electrically connecting the semiconductor chip and the header portion of the lead electrode, and a sealing member sealing the semiconductor chip, the header portion of the lead electrode, the first connection layer, and the second connection layer; The lead portion is coupled to the header portion so as to extend upward from the header portion, thereby forming a lead electrode that is an opposite electrode to the base electrode.

8. 8. A combination structure of a body and a lead of a semiconductor device according to claim 7, A combined structure of a body and a lead of a semiconductor device, in which the lead is coupled to the header by fitting the lead and the header together or by screwing the lead and the header together.

9. 8. A combination structure of a body and a lead of a semiconductor device according to claim 7, The header portion has a protrusion that protrudes upward from the center of an upper surface thereof, The lead portion has a combined structure of a main body portion of a semiconductor device and a lead portion which is connected to the protrusion portion.

10. 8. A combination structure of a body and a lead of a semiconductor device according to claim 7, The lead electrode has a combined structure of a body and a lead portion of the semiconductor device, the length of which protrudes from the sealing member to the outside being 20 mm or more.

11. 8. A power converter formed by combining the body and leads of the semiconductor device according to claim 7.

12. A semiconductor device according to any one of claims 7 to 11, which is formed by combining the body parts and the lead parts of a plurality of semiconductor devices, The power conversion device includes a plurality of semiconductor device body portions each having a combination structure with a different appearance for each type of semiconductor chip.

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