JP2012015167A - Semiconductor module and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor module and a manufacturing method of the same which can sufficiently exert radiation performance by cooling fins while keeping an excellent junction between an insulation layer and the cooling fins.SOLUTION: The semiconductor module manufacturing method in which a heat spreader 13, 14 and a cooling fin 18, 19 are formed separately and the heat spreader 13, 14 and the cooling fin 18, 19 are joined via an insulation film 13b, 14b formed on a surface of the heat spreader 13, 14 comprises the steps of forming the cooling fin 18, 19 by placing a flat plate part 18b, 19b on a fin part 18a, 19a to bond fin peaks of the fin part 18a, 19a with the flat plate part 18b, 19b by brazing such that fillets 51 are formed at bonded parts of the fin peaks of the fin part 18a, 19a with the flat plate part 18b, 19b, and bonding the flat plate part 18b, 19b of the cooling fin 18, 19 with the insulation film 13b, 14b by soldering.

Description

  The present invention relates to a semiconductor module in which a semiconductor chip on which a semiconductor power element that performs heat dissipation by a heat spreader (heat radiating plate) is formed and a heat spreader are resin-molded to form an integrated structure, for example, an upper arm (high side) of an inverter 1 in 1 structure in which one of the semiconductor power elements of the side element) and the lower arm (low side element) is molded in a resin mold part, or a 2 in 1 structure in which two semiconductor power elements of the upper and lower arms are molded in one resin mold part It is preferable to apply to a semiconductor module such as

  2. Description of the Related Art Conventionally, in a semiconductor module, a semiconductor chip on which a semiconductor power element is formed and a heat spreader for radiating heat from the semiconductor chip are generally molded by resin molding to have an integrated structure. And as such a semiconductor module, in order to raise heat dissipation efficiency more, the heat spreader which integrated the cooling fin is used (for example, refer patent document 1). Such a semiconductor module is provided with a cooling mechanism through which a coolant such as cooling water flows, and the heat generated by the semiconductor power element is released well by arranging the cooling fin side of the heat spreader in contact with the coolant flow. I try to do it.

  However, when the heat spreader is arranged so as to be in contact with the refrigerant, the heat spreader energizes the refrigerant. For this reason, there is a possibility that heat spreaders for heat dissipation of a plurality of semiconductor chips arranged side by side are connected to each other through the refrigerant, and a stray current is generated in the refrigerant, so that it contacts the refrigerant including other parts in the cooling circuit. There is a possibility that electrolytic corrosion occurs in the metal and a through hole is formed.

  Thus, conventionally, an insulator is provided on the surface of the heat spreader to prevent energization from the heat spreader to the refrigerant. In the case of a heat spreader in which cooling fins are integrated, an insulating material is formed on the surface of the cooling fins to prevent energization from the heat spreader to the refrigerant.

JP 2006-165534 A

  However, it is difficult to form a highly reliable insulator on the surface of the uneven cooling fin. That is, as a method for forming an insulator on the surface of the cooling fin, it may be possible to adopt a vapor phase growth method such as sputtering, CVD, or thermal spraying, but it is difficult to form an insulator uniformly in the gap between the cooling fins. . For this reason, there is a possibility that leakage from the heat spreader cannot be prevented accurately.

  In general, a heat spreader integrated with a cooling fin is formed by cutting, forging, extrusion molding, or the like, but it is difficult to form a fine fin shape by these processing methods. For this reason, it is difficult to ensure a sufficient heat transfer area.

  Therefore, as a method for solving these problems, it is conceivable that the heat spreader and the cooling fin are configured separately and the heat spreader and the cooling fin are joined via an insulating film formed on the surface of the heat spreader. According to this, by forming the insulating film on the flat surface of the heat spreader, the insulating film can be formed uniformly and a highly reliable insulating film can be formed. Further, by making the heat spreader and the cooling fins separate, corrugated fins that are cooling fins having high heat radiation performance can be adopted as the cooling fins.

  However, in this method, it is necessary to bond the insulating film and the cooling fin. As this bonding method, bonding using an adhesive or bonding using ultrasonic welding can be considered.

  However, in both joining methods, there is a problem that the thermal conductivity between the heat spreader and the cooling fin is low. That is, when an adhesive is used, it is difficult to prepare an adhesive having the same degree as that of a metal, and the thermal conductivity of the adhesive is generally lower than that of a metal, so that the heat conduction between the heat spreader and the cooling fins is difficult. It becomes low. Further, in the joining by ultrasonic welding, the joining area between the corrugated fin and the insulating film is narrow and the heat conduction area is narrow, so that the thermal conductivity between the heat spreader and the cooling fin is lowered. As a result, the heat dissipation performance by the cooling fins is not sufficiently exhibited.

  In view of the above points, the present invention provides a semiconductor module having a structure capable of sufficiently exhibiting heat dissipation performance by a cooling fin while obtaining good bonding between the insulating film and the cooling fin, and a method for manufacturing the same. With the goal.

In order to achieve the above object, in the first aspect of the present invention, the semiconductor chip (11), the first and second heat spreaders (13, 14), and the terminals (15-17) are molded by the resin mold part (20). As a single unit (10), a semiconductor module in which both ends of the unit (10) are sandwiched between lids (40, 41) and fixed with a fixture (43),
Of the first and second heat spreaders (13, 14), the surface opposite to the semiconductor chip (11) is a flat surface, and this flat surface is provided with insulating films (13b, 14b) covering the flat surface. In addition, corrugated cooling fins (18, 19) having a corrugated cross section are joined via the insulating films (13b, 14b),
The cooling fins (18, 19) are formed by overlapping the fin portions (18a, 19a) having a plurality of fin peaks and the flat plate portions (18b, 19b) on the fin portion side of the flat plate portions (18b, 19b). The surface and the fin portion (18a, 19a) of the flat plate portion side are joined by brazing, and the flat plate portion (18b, 19b) is opposite to the fin portion (18a, 19a). And the insulating film (13b, 14b) are joined by soldering,
It is characterized in that a fillet (51) made of a brazing material is formed at a joint portion between the fin portions (18a, 19a) and the flat plate portions (18b, 19b).

  According to this, the structure of the corrugated type cooling fin is configured such that the fin portion and the flat plate portion are overlapped, and the fin crest of the fin portion and the flat plate portion are joined by brazing, and is insulated from the flat plate portion of the cooling fin. Since the film is joined by soldering, good bonding can be obtained between the fin portion and the flat plate portion or between the flat plate portion and the insulating film.

  Further, in the present invention, since the metal and the solder are joined using a solder and a brazing material having higher thermal conductivity than a general adhesive, the heat spreader and the cooling fin are compared with the case where the adhesive is joined. The thermal conductivity between can be improved. Further, in the present invention, since the fillet is formed at the joint portion, the joint region at the joint portion of the fin crest can be widened as compared with the case where the fillet is not formed at the joint portion as in ultrasonic welding. The heat conductivity between the heat spreader and the cooling fin can be improved.

  Therefore, according to the present invention, the heat radiation performance by the cooling fins can be sufficiently exhibited while obtaining a good bond between the insulating film and the cooling fins.

  In the present invention, for example, as described in claim 2, a wave fin in which fin peaks are arranged in a wave shape in a plan view can be adopted as the fin portion (18a, 19a).

  Furthermore, in the case of adopting wave fins, as described in claim 3, the cooling fins (18, 19) with respect to one wavy fin portion (18a, 19a) of the cooling fins (18, 19). The other wavy fin portions (18a, 19a) are preferably 180 ° out of phase and have a planar layout in which a cross-wave shape is formed. This is because more turbulent flow can be generated by the refrigerant passing through the cooling fins, and the heat dissipation performance of the cooling fins can be further enhanced by the turbulent flow.

Moreover, in invention of Claim 4, it is a manufacturing method of the semiconductor module as described in any one of Claims 1-3,
A metal plate (50) in which the fin portions (18a, 19a) and the flat plate portions (18b, 19b) are integrally formed is prepared, and the fin portions (18a, 19a) and the flat plate portions (18b) of the metal plate (50) are prepared. 19b), the fin portions (18a, 19a) and the flat plate portions (18b, 19b) are overlapped with each other, and the fins of the flat plate portions (18b, 19b) are folded. The cooling fins (18, 19) are formed by joining the surface on the part side and the fin crest on the flat plate part side among the fin parts (18a, 19a) by brazing,
The flat plate portions (18b, 19b) of the formed cooling fins (18, 19) and the insulating films (13b, 14b) are joined by soldering.

  As described above, in the formation of the cooling fin, the metal plate in which the fin portion and the flat plate portion are integrally formed is bent at the bent portion, thereby adopting a method of superimposing the fin portion and the flat plate portion. Compared with the case where a part and a flat plate part are formed in a different body, productivity of a cooling fin can be improved.

  In the invention described in claim 4, for example, as described in claim 5, the fin portions (18 a, 19 a) and the flat plate portion are used as the metal plate (50) for brazing the fin portion and the flat plate portion. It is preferable to use a clad material in which a brazing material is clad on the surface of the base material which becomes the overlapping surface with (18b, 19b).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing of the semiconductor module 1 in 1st Embodiment of this invention. FIG. 2 is a view of one unit 10 constituting the semiconductor module 1 shown in FIG. 1, wherein (a) is a plan view of the unit 10, (b) is an AA ′ cross-sectional view of (a), and (c). FIG. 4B is a sectional view taken along line BB ′ in FIG. FIG. 3 is an enlarged cross-sectional view of cooling fins 18 and 19 and heat spreaders 13 and 14. It is sectional drawing which showed the manufacturing process of the semiconductor module 1 shown in FIG. 5 is a cross-sectional view showing a manufacturing process of cooling fins 18 and 19. FIG. FIG. 6 is an enlarged view of a region C in FIG. It is a plane layout figure of the cooling fins 18 and 19 which the unit 10 which adjoins among the units 10 which comprise the semiconductor module 1 in 2nd Embodiment opposes. It is a plane layout figure of cooling fins 18 and 19 of unit 10 which constitutes semiconductor module 1 in a 3rd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
The semiconductor module provided with the cooling mechanism in the first embodiment of the present invention will be described. This semiconductor module is applied to, for example, an inverter for driving a three-phase motor for a vehicle.

  FIG. 1 is a cross-sectional view of a semiconductor module 1 in the present embodiment. As shown in this figure, a semiconductor module 1 includes, for example, a unit 10 formed by resin-molding various components such as a semiconductor chip 11 on which a semiconductor power element or the like constituting an inverter is formed. It is configured by stacking.

  2A and 2B are views of one of the units 10 constituting the semiconductor module 1, wherein FIG. 2A is a plan view of the unit 10, FIG. 2B is a cross-sectional view taken along line AA ′ in FIG. FIG. 4B is a sectional view taken along line BB ′ in FIG. 1 and 2, the cooling fins 18 and 19 are simplified (the flat plate portions 18b and 19b are omitted).

  As shown in FIGS. 2A to 2C, each unit 10 includes a metal block 12, heat spreaders 13 and 14, a positive electrode lead 15, and a negative electrode lead 16 in addition to the semiconductor chip 11 on which the semiconductor power element is formed. The control terminals 17 and the like are provided, and these are integrated by being resin-molded by the resin mold portion 20. Each unit 10 is provided with cooling fins 18 and 19, and the cooling fins 18 and 19 can obtain higher heat radiation efficiency.

  Here, a 1 in 1 structure in which each unit 10 includes only one semiconductor chip 11 on which a semiconductor power element is formed will be described. However, a 2 in 1 structure in which two semiconductor chips 11 are provided, and a 3 in 1 in which three semiconductor chips 11 are provided. Other units, such as the structure, can also be a unit. For example, in the case of an inverter, it is assumed that the two-in-1 structure is formed by molding two semiconductor chips 11 constituting the upper and lower arms to form an integrated structure, and the three-in1 structure is a three-phase upper arm or lower arm 3. A case where one semiconductor chip 11 is molded to form an integrated structure is assumed.

  A semiconductor power element such as an IGBT or a power MOSFET is formed on the semiconductor chip 11. For example, when the semiconductor module 1 is applied to an inverter for driving a three-phase motor, a semiconductor power element that constitutes either the upper arm or the lower arm and a free wheel diode (hereinafter referred to as FWD) are integrated into one chip. This is the semiconductor chip 11. In the present embodiment, the semiconductor power element is a vertical semiconductor element that allows a current to flow in the substrate thickness direction, and various pads are formed on the front surface side and the back surface side of the semiconductor chip 11. Specifically, a pad connected to the gate or the like of the semiconductor power element is formed on the front surface side of the semiconductor chip 11, and a pad connected to the emitter of the semiconductor power element is formed. The entire back surface is a pad connected to the collector of the semiconductor power element.

  In FIG. 2, the semiconductor chip 11 is illustrated as a single chip structure, but a structure in which the semiconductor power element and the FWD are formed on separate chips may be used. Further, a structure in which a lateral semiconductor power element that allows current to flow in the substrate lateral direction is formed in the semiconductor chip 11 may be used.

  The metal block 12 is made of a metal having a high heat transfer coefficient, such as copper or aluminum. The metal block 12 is electrically and physically connected to a pad connected to the emitter of the semiconductor power element formed on the surface side of the semiconductor chip 11 via solder or the like. By providing the metal block 12 on the surface side of the semiconductor chip 11, the distance from the surface of the semiconductor chip 11 to the heat spreader 14 is spaced by a predetermined interval.

  The heat spreaders 13 and 14 function as a heat radiating plate that diffuses and dissipates heat transmitted from the semiconductor chip 11 over a wide range. One heat spreader 13 is not only physically but also electrically connected to the pad on the back surface side of the semiconductor chip 11, so that the wiring connected to the collector of the semiconductor power element in addition to the function as a heat sink It is functioning as well. Further, the other heat spreader 14 is electrically and physically connected to the metal block 12, thereby functioning as a wiring connected to the emitter of the semiconductor power element in addition to the function as a heat sink. Yes. Of these heat spreaders 13 and 14, the surface opposite to the semiconductor chip 11 is exposed from the resin mold part 20. The cooling fins 18 and 19 for promoting heat dissipation (cooling) are joined to the exposed surface, so that cooling with cooling water can be performed via the cooling fins 18 and 19.

  In addition, the heat spreaders 13 and 14 have an insulating structure for preventing energization from the heat spreaders 13 and 14 to the cooling water, and the cooling fins 18 and 19 can be joined.

  Specifically, as shown in FIGS. 1, 2B, and 2C, the heat spreaders 13 and 14 include metal plates 13a and 14a and an insulating film 13b formed on the surfaces of the metal plates 13a and 14a. 14b.

  The metal plates 13a and 14a are portions that function mainly as heat sinks and current paths, and are made of, for example, a rectangular member having a predetermined thickness, and are made of a metal such as copper having high heat transfer coefficient and high conductivity. ing.

  The insulating films 13b and 14b are formed on the surface of the metal plates 13a and 14a opposite to the semiconductor chip 11. The insulating films 13b and 14b are made of an insulating material such as SiN or alumina, and are formed by, for example, a vapor phase growth method such as sputtering, CVD, or thermal spraying. Since the surfaces on which the insulating films 13b and 14b are formed of the metal plates 13a and 14a are flat surfaces, the thicknesses of the insulating films 13b and 14b are almost uniform.

  Thus, since the insulating films 13b and 14b are provided on the cooling water side of the heat spreaders 13 and 14 on the cooling water side from the metal plates 13a and 14a electrically connected to the semiconductor chip 11, the insulating films 13b and 14b Insulation with cooling water is achieved. For this reason, energization from the heat spreaders 13 and 14 to the cooling water is suppressed, and the occurrence of corrosion or the like can be suppressed as described in the background art section.

  The positive electrode lead 15 constitutes a positive electrode terminal of the semiconductor chip 11. The positive electrode lead 15 is joined to the heat spreader 13 by integral molding or soldering or welding, and is electrically connected to a pad connected to the collector of the semiconductor power element provided on the back surface side of the semiconductor chip 11 via the heat spreader 13. Has been. Further, the end portion of the positive electrode lead 15 opposite to the end portion joined to the heat spreader 13 is exposed from the resin mold portion 20, and is configured to be able to be connected to the outside through this exposed portion.

  The negative electrode lead 16 constitutes the negative electrode terminal of the semiconductor chip 11. The negative electrode lead 16 is joined to the heat spreader 14 by integral molding, soldering, welding, or the like, and is electrically connected to a pad connected to the emitter of the semiconductor power element provided on the surface side of the semiconductor chip 11 via the heat spreader 14. Has been. Further, the end portion of the negative electrode lead 16 opposite to the end portion joined to the heat spreader 14 is exposed from the resin mold portion 20, and is configured to be able to be connected to the outside through this exposed portion.

  The control terminal 17 is used to sense the gate wiring of the semiconductor power element, the current flowing through the semiconductor power element, the temperature of the semiconductor chip 11, etc., and the gate of the semiconductor power element formed on the surface side of the semiconductor chip 11. Are electrically connected via a bonding wire 17a. An end portion of the control terminal 17 opposite to the end portion connected to the semiconductor chip 11 is exposed from the resin mold portion 20, and is configured to be connected to the outside through the exposed portion. Since the surface of the semiconductor chip 11 and the heat spreader 14 are separated by a predetermined distance by the metal block 12, the bonding wire 17a does not interfere with the heat spreader 14, and the semiconductor chip 11 and the control terminal 17 are favorably connected. Electrical connection can be made.

  The cooling fins 18 and 19 are joined to the exposed surfaces of the heat spreaders 13 and 14, that is, the surfaces of the insulating films 13b and 14b by soldering. The cooling fins 18 and 19 are corrugated fins made of a metal material having a high thermal conductivity such as aluminum and having a corrugated cross section. The cooling fins 18 and 19 may have any planar layout as long as they are corrugated fins. In the present embodiment, as shown in FIG. The fins are wave fins with undulations.

  Here, FIG. 3 shows an enlarged cross-sectional view of the cooling fins 18 and 19 and the heat spreaders 13 and 14. Although FIG. 3 shows the cooling fins 18, the cooling fins 19 have the same shape, and the reference numerals corresponding to the cooling fins 19 are given in parentheses in FIG. 3. . Similarly, for the heat spreaders 13 and 14, the heat spreader 14 is shown in parentheses.

  As shown in FIG. 3, the cooling fin 18 (19) has a fin portion 18a (19a) and a flat plate portion 18b (19b), and the fin portion 18a (19a) is joined to the flat plate portion 18b (19b). The flat plate portion 18b (19b) is joined to the insulating film 13b (14b).

  The fin portion 18a (19a) is a portion that forms a corrugated fin having a plurality of fin crests formed so that the fin crests are alternately positioned up and down and having a corrugated cross section. In FIG. 3, the top of the fin crest has a flat surface, but may have a shape having a corner or a curved surface.

  The flat plate portion 18b (19b) is a flat plate portion. In the present embodiment, the flat plate portion 18b (19b) is integral with the fin portion 18a (19a), and is bent by the bent portion 18c (19c), whereby the flat plate portion 18b (19b) and the fin portion 18a (19a). And are superimposed.

  And in the junction part of flat plate part 18b (19b) and fin part 18a (19a), the fin part side is located on the heat spreader side of fin part 18a (19a), and fin part side among flat plate part 18b (19b) Are joined by brazing. For this reason, the fillet 51 is formed in the junction part of a fin peak and the flat plate part 18b (19b). Incidentally, the “fillet” means a portion of the brazing that protrudes from between the finned portion and the flat plate portion, as shown in FIG.

  On the other hand, the surface of the flat plate portion 18b (19b) opposite to the fin portion and the insulating film 13b (14b) are joined by soldering.

  The resin mold part 20 shown in FIGS. 1 and 2 is provided for each component (semiconductor chip 11, metal block 12, heat spreaders 13 and 14, positive electrode lead 15, negative electrode lead 16, and control terminal 17) provided in the unit 10 described above. After the connection is completed in the mold, the resin is injected into the mold and molded. Specifically, the resin mold part 20 is molded with a thermosetting resin mold part 21 obtained by molding each component with a thermosetting resin, and a thermoplastic resin so as to surround the outer edge of the thermosetting resin mold part 21. It is comprised by the thermoplastic resin mold part 22 which changed.

  The thermosetting resin mold portion 21 is made of, for example, a thermosetting resin such as an epoxy resin, and exposes one end side of the positive electrode lead 15, the negative electrode lead 16, and the control terminal 17 while covering the above-described components. And one surface side of the heat spreaders 13 and 14 is exposed. In the resin mold part 20, only the thermosetting resin mold part 21 can waterproof each component. Further, the thermosetting resin mold part 21 has a rectangular plate shape in which one direction is a longitudinal direction, and the positive electrode lead 15 and the negative electrode lead 16 are drawn out from one side surface constituting the long side, and the long side The control terminal 17 is pulled out from one side surface that constitutes the long side opposite to. For this reason, a power card is constituted by covering each component with the thermosetting resin mold part 21, and only the portion of the power card can be reused.

  On the other hand, the thermoplastic resin mold part 22 is made of, for example, a thermosetting resin such as polyphenylene sulfide (PPS) resin, and covers the outer edge of the thermosetting resin mold part 21 while thermosetting among the constituent parts. A portion exposed from the conductive resin mold portion 21, that is, one end side of the positive electrode lead 15, the negative electrode lead 16 and the control terminal 17 and one surface side of the heat spreaders 13 and 14 are exposed. The thermoplastic resin mold part 22 is formed in a frame shape, and the heat spreaders 13 and 14 are exposed through the window parts 22a and 22b, with the insides of the thermoplastic resin mold part 22 being window parts 22a and 22b.

  Further, the thermoplastic resin mold portion 22 constitutes a part of a water passage 30 (see FIG. 1) as a refrigerant passage constituting the cooling mechanism of the semiconductor module 1. Specifically, the thermoplastic resin mold part 22 of this embodiment is also composed of a rectangular plate-like member having the same direction as the longitudinal direction of the thermosetting resin mold part 21 as the longitudinal direction. The thermoplastic resin mold portion 22 includes a passage hole 22 c that forms a main water channel formed in a portion protruding outward from both longitudinal ends of the thermosetting resin mold portion 21, and both surfaces of the thermoplastic resin mold portion 22. A recess 22d that is recessed from the outer edge is formed. These passage holes 22c and recesses 22d constitute a part of the water channel 30, and when the plurality of units 10 are stacked, the water channel 30 including each passage hole 22c and the recess 22d is configured.

  Further, the thermoplastic resin mold portion 22 is formed with a seal member setting groove portion 22e formed so as to surround the recess portion 22d. An O-ring 42 (see FIG. 1) described later is fitted into the groove 22e. And when the several unit 10 is laminated | stacked, the seal between units 10 is made by O-ring 42, and it prevents that the cooling water as a refrigerant | coolant which flows into the water path 30 leaks outside the resin mold part 20. FIG. ing. Each unit 10 is configured by such a structure.

  Further, as shown in FIG. 1, the semiconductor module 1 includes a lid 40, a pipe-attached lid 41, an O-ring 42, and a fixture 43.

  The lid portion 40 and the pipe-equipped lid portion 41 are respectively disposed at both end portions when a plurality of the units 10 configured as described above are stacked. The lid portion 40 is composed of a plate-like member having a shape corresponding to the resin mold portion 20 of each unit 10. When arranged at one end of the stacked body of the unit 10 in which a plurality of the lid portions 40 are laminated, a gap due to the concave portion 22 d is formed between the lid portion 40 and the unit 10. On the other hand, the pipe-equipped lid portion 41 is configured to include two pipes 41 a and 41 b with respect to a plate-like member having a shape corresponding to the resin mold portion 20 of each unit 10. One of the two pipes 41a and 41b is an inlet of the cooling water, and the other is an outlet of the cooling water. The pipes 41a and 41b are arranged at positions corresponding to the passage holes 22c formed in each unit 10, respectively. In addition, a groove 41c for setting a seal member is formed on the surface on the unit 10 side of the lid portion 41 with a pipe.

  The O-ring 42 is fitted into the groove 22e for sealing member set formed in each unit 10 or the groove 41c for sealing member set formed in the pipe-attached lid 41, and between the stacked units 10 or The space between the unit 10 and the lid 40 and the pipe-attached lid 41 is sealed.

  The fixing tool 43 is configured such that the O-ring 42 is fitted into the groove 22e and the groove 41c, and the lid 40 and the pipe-equipped lid 41 are disposed at both ends of the plurality of stacked units 10, and then the lid 40 and the pipe It fixes by pinching from the both sides of the cover part 41. FIG. By being fixed by this fixing tool 43, the semiconductor module 1 in which the water channel 30 by the passage holes 22c and the recesses 22d formed in the pipes 41a and 41b and each unit 10 is configured is configured. The fixture 43 is configured to be detachable, and by removing the fixture 43, each unit 10, the lid portion 40, and the pipe-attached lid portion 41 can be disassembled. In this embodiment, both ends of the fixing tool 43 are hooks, and the distance between the hooks at both ends is narrower than the width when the lid 40, the plurality of units 10, and the pipe-attached lid 41 are stacked. It can be fixed by the elastic force of both hooks. Here, the fixing tool 43 has a structure in which hooks are provided at both ends, but it is needless to say that the fixing tool 43 can be fixed by screwing.

  The semiconductor module 1 concerning this embodiment is comprised by the above structures. The semiconductor module 1 having such a configuration prevents leakage of cooling water from the water channel 30 because the O-ring 42 seals between the units 10 and between the unit 10 and the lid 40 and the lid 41 with pipe. However, the semiconductor chip 11 provided in each unit 10 can be cooled by a high cooling effect by the cooling water. In particular, since the surfaces of the heat spreaders 13 and 14 are provided with the cooling fins 18 and 19 for promoting heat dissipation, the heat dissipation area can be further increased and a higher cooling effect can be obtained.

  Specifically, as shown in FIG. 1, one main water channel 31 is formed in one of two pipe holes 22 c formed in the pipe 41 a and each unit 10, and is formed in each unit 10. The other main water channel 32 constituted by the other of the two passage holes 22c and the pipe 41b is formed. Further, a branch water channel 33 is formed by the recess 22 d of each unit 10. For this reason, as indicated by arrows in FIG. 1, the cooling water supplied from the pipe 41 a reaches each unit 10 through one main water channel 31 and then moves to the other main water channel 32 side through the branch water channel 33. Further, the water is discharged from the main water channel 32 through the pipe 41b. At this time, since the heat spreaders 13 and 14 and the cooling fins 18 and 19 provided in each unit 10 are cooled in contact with the cooling water, the heat generated by the semiconductor chip 11 can be effectively released.

  Next, a method for manufacturing the semiconductor module 1 configured as described above will be described. FIG. 4 is a cross-sectional view showing a manufacturing process of the semiconductor module 1 shown in FIG. In FIG. 4, the cooling fins 18 and 19 are shown in a simplified manner. With reference to this figure, the manufacturing method of the semiconductor module 1 is demonstrated.

[Step of FIG. 4A]
First, a lead frame in which the positive electrode lead 15, the negative electrode lead 16, and the control terminal 17 are integrated is prepared, the lead frame is disposed on the surface side of the heat spreader 13, and the positive electrode lead 15 is joined to the surface of the heat spreader 13 by soldering or the like. . Further, after mounting the semiconductor chip 11 on which the semiconductor power element such as IGBT or FWD is formed on the surface of the heat spreader 13 via solder or the like, it is connected to the gate of the semiconductor power element formed on the surface of the semiconductor chip 11. The pad and the control terminal 17 are connected by a bonding wire 17a. Subsequently, the metal block 12 is joined to the surface of the semiconductor chip 11 via solder or the like. Further, after solder or the like is placed on the surface of the metal block 12 or the negative electrode lead 16, the heat spreader 14 is disposed thereon, and the metal block 12 or the negative electrode lead 16 and the heat spreader 14 are joined. In the present embodiment, the heat spreaders 13 and 14 in which the insulating films 13b and 14a are formed on the surfaces of the metal plates 13a and 14a are used.

[Step of FIG. 4B]
After each component connected to each part is placed in a molding die such as a transfer molding machine, a thermosetting resin such as an epoxy resin is injected into the molding die to form a thermosetting resin mold part 21. Thereby, a power card is configured. At this time, the heat spreaders 13 and 14 may be molded so that the surface opposite to the semiconductor chip 11 is exposed from the beginning, but here the thermosetting resin mold is applied to the surfaces of the heat spreaders 13 and 14. The part 21 is covered.

[Step of FIG. 4C]
A flat processing apparatus such as cutting or grinding is prepared, whereby a part of the thermosetting resin mold portion 21 covering the surface of the heat spreaders 13 and 14 is removed, and the heat spreaders 13 and 14 are exposed.

[Step of FIG. 4D]
After the power card in which each component is molded by the thermosetting resin mold part 21 is placed in another mold, a thermoplastic resin such as polyphenylene sulfide resin is injected into the mold, and the thermoplastic resin mold part 22 is formed.

[Step of FIG. 4 (e)]
Separately manufactured cooling fins 18 and 19 are joined to the surfaces of the heat spreaders 13 and 14 exposed from the thermosetting resin mold portion 21 by soldering.

  Here, a method of manufacturing the cooling fins 18 and 19 will be described. FIG. 5 is a cross-sectional view showing the manufacturing process of the cooling fins 18 and 19.

[Step of FIG. 5A]
One metal plate 50 is prepared. As the metal plate 50, a clad material in which a base material is made of aluminum or the like and a brazing material layer is clad in advance on one side of the base material, which is an overlapping surface of the fin portion and the flat plate portion, is used. Moreover, as this metal plate 50, the thing of thickness of 0.1 mm or less is used, for example.

  And fin part 18a, 19a and flat plate part 18b, 19b are formed in this metal plate 50. FIG. The fin portions 18a and 19a are formed by a press molding method. As the press forming method, the metal plate 50 is sequentially fed to form the fin crests in a plurality of times, or the fin portions 18a and 19a are formed by one press (one-time press forming). It is possible to employ a method of drawing (pulling) while a metal plate is brought into the press die. The remaining portions of the metal plate 50 where the fin portions 18a and 19a are formed become the flat plate portions 18b and 19b.

[Step of FIG. 5B]
The metal plate 50 in which the fin portions 18a and 19a and the flat plate portions 18b and 19b are integrally formed is bent. Here, FIG. 6 shows an enlarged view of a region C in FIG. In this bending, as shown in FIG. 6, the starting point is a slit 18d formed between the fin portions 18a, 19a and the flat plate portions 18b, 19b. The slit 18d may be formed either before or after the fin portions 18a and 19a are formed. As a result, the metal plate 50 is bent at the bent portion 18c, and the fin portions 18a and 19a and the flat plate portions 18b and 19b are overlapped.

  Thus, by setting the position of the slit 18d to a predetermined position in advance, the fin portions 18a, 19a and the flat plate portions 18b, 19b can be overlapped only by bending, and the fin portions 18a, 19a and the flat plate portion 18b, The alignment process with 19b becomes unnecessary.

[Step of FIG. 5C]
The superposed fin portions 18a and 19a and the flat plate portions 18b and 19b are brazed. Here, the cooling fins 18 and 19 are brazed separately from the power card. In this brazing, the heating temperature is set to 600 ° C., for example, and heating is performed while suppressing both end portions where the fin portions 18a and 19a and the flat plate portions 18b and 19b are in close contact so as not to crush the fin crests.

  Thereby, between the fin part 18a, 19a between the fin crest on the flat plate part side and the flat plate part 18b, 19b is joined by the brazing material on the mating surface, and the brazing material protrudes from both, so that the fillet 51 is formed. It is formed. In this way, the cooling fins 18 and 19 are manufactured.

  In the step shown in FIG. 4E, the insulating film on the surfaces of the cooling fins 18 and 19 and the heat spreaders 13 and 14 is heated, for example, by suppressing both ends of the cooling fins 18 and 19 so as not to crush the fin crests. 13a and 14a are soldered. Thereby, the unit 10 is formed.

  Thereafter, as shown in FIG. 1, a plurality of units 10 (three in the case of the present embodiment) that have been implemented up to the step of FIG. 4E are prepared, and the thermoplastic resin mold portion 22 in each unit 10 is prepared. The O-ring 42 is fitted into the groove 22e. Then, a plurality of units 10 (three in FIG. 1) are stacked.

  Next, a lid 40 and a pipe-equipped lid 41 are prepared, and an O-ring 42 is fitted in a seal member setting groove 41 c formed in the pipe-equipped lid 41. And the cover part 40 is arrange | positioned at one front-end | tip part of the lamination direction of the some unit 10 laminated | stacked, and the cover part 41 with a pipe is arrange | positioned at the other front-end | tip part.

  Next, a stack of the lid 40, the plurality of units 10, and the pipe lid 41 is fixed with a fixture 43. Thereby, the semiconductor module 1 of this embodiment shown in FIG. 1 is completed.

  As described above, in the semiconductor module 1 of this embodiment, the heat spreaders 13 and 14 and the cooling fins 18 and 19 are configured separately, and the heat spreaders 13 and 14 are formed of the metal plates 13a and 14a and the insulating films 13b and 14b. The cooling fins 18 and 19 are retrofitted.

  Unlike this, when the cooling fin is integrated with the heat spreader as in the prior art, it has a hole for the cooling fin to enter in order to prevent the mold resin from entering between the cooling fins during resin molding. A mold must be used. When such a mold is used, it is difficult to position the cooling fin and the hole into which the cooling fin enters, and at the same time, there is a problem that the cooling fin is deformed, broken or contaminated when the cooling fin is inserted into or removed from the hole. To do.

  Therefore, since the cooling fins 18 and 19 are separated from the heat spreaders 13 and 14 as in the present embodiment, the resin molding portion 21 can be molded without the cooling fins 18 and 19. The manufacturing process can be simplified, and the cooling fins 18 and 19 can be prevented from being deformed, broken or contaminated.

  Further, according to the present embodiment, the insulating films 13b and 14b provided in the heat spreaders 13 and 14 can prevent the heat spreaders 13 and 14 from being energized to the cooling water, and the cooling fins 18 and 19 can be connected to the heat spreaders 13 and 14. Since the cooling fins 18 and 19 can be formed separately, corrugated fins having a fine shape and high heat dissipation performance can be adopted.

  Further, according to the present embodiment, the cooling fins 18 and 19 are configured such that the fin portions 18a and 19a and the flat plate portions 18b and 19b are overlapped, and the fin crests of the fin portions 18a and 19a and the flat plate portions 18b and 19b are combined. Since the flat plate portions 18b and 19b of the cooling fins 18 and 19 and the insulating films 13b and 14b are bonded by soldering, the fin portions and the flat plate portions, or the flat plate portions and the insulating portions are joined. Good bonding can be obtained between the films.

  In addition, according to the present embodiment, the heat spreader 13 is compared with the case where the heat spreader 13 is bonded with the adhesive because the metal is bonded using the solder and the brazing material having higher thermal conductivity than the general adhesive. The thermal conductivity between 14 and the cooling fins 18 and 19 can be improved. In the present invention, since the fillet 51 is formed at the joint between the fin crest of the fin portions 18a and 19a and the flat plate portions 18b and 19b, the fillet is not formed at the joint as in ultrasonic welding. As compared with the above, it is possible to widen the joint region at the joint portion of the fin crest, and to improve the thermal conductivity between the heat spreaders 13 and 14 and the cooling fins 18 and 19.

  Therefore, according to this embodiment, compared with the case where the joining by an adhesive agent or ultrasonic welding is employ | adopted, the thermal radiation performance by the cooling fins 18 and 19 can fully be exhibited.

  Here, unlike the present embodiment, it is conceivable that the flat plate portions 18b and 19b of the present embodiment are omitted and the fin crests of the fin portions 18a and 19a are directly joined to the insulating films 13b and 14b. However, in this case, if a bonding failure occurs between the fin crests of the fin portions 18a and 19a and the insulating films 13b and 14b, the entire unit 10 becomes a defective product.

  On the other hand, in this embodiment, since the cooling fins 18 and 19 are brazed individually in the steps of FIGS. 5A to 5C, the fin peaks of the fin portions 18a and 19a are flat after brazing. It is possible to confirm (inspect) whether the portions 18b and 19b are well bonded. As a result, it is possible to prevent the cooling fin in which the bonding failure has occurred between the fin crest and the flat plate portion from being joined to the heat spreaders 13 and 14, and the fin crest can be guaranteed.

  Further, unlike the present embodiment, when the flat plate portions 18b and 19b of the present embodiment are omitted and the fin crests of the fin portions 18a and 19a are directly joined to the insulating films 13b and 14b, the fins located on the insulating film side. Since it is necessary to apply a load to the entire cooling fin in order to bring the mountain into close contact with the insulating film, the fin mountain may be crushed.

  On the other hand, in the present embodiment, the flat plate portions 18b and 19b and the insulating films 13b and 14b are soldered in the process of FIG. 4E in which the cooling fins 18 and 19 are joined to the insulating films 13 and 14. By applying a load to part of both ends of the cooling fins 18 and 19, the fin crest can be prevented from being crushed. This is because when a load is applied to a part of the flat plate portions 18b and 19b, stress is dispersed over the entire surface of the flat plate portions 18b and 19b.

  Further, if solder fins are used to directly join the fin crests of the fin portions 18a and 19a to the insulating films 13b and 14b, the solder flows into the cooling water passage formed by the fin portions 18a and 19a, so that the cooling water passage There is a risk of being blocked.

  On the other hand, according to the present embodiment, since the plate portions 18b and 19b and the insulating films 13b and 14b are soldered, such a problem can be prevented.

(Second Embodiment)
In the present embodiment, the layout of the fin crests in the plan view of the cooling fins 18 and 19 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Only portions different from the embodiment will be described.

  FIG. 7 is a plan view showing the opposing cooling fins 18 and 19 of the adjacent units 10 among the units 10 constituting the semiconductor module 1 in this embodiment, and the cooling fins when viewed from the upper side of FIG. This corresponds to 18 and 19 layouts.

  In this embodiment, as shown in FIG. 7, the fin direction of the adjacent unit 10 is reversed and the several unit 10 is laminated | stacked. That is, for the opposing cooling fins 18 and 19 provided in the adjacent units 10, the wave formed by the fins of the cooling fin 18 and the wave formed by the fins of the cooling fin 19 are 180 degrees out of phase. The cross-wave shape is a good relationship.

  As described above, a planar layout in which a cross wave shape is formed by the cooling fins 18 and 19 makes it possible to generate more turbulent flow in the cooling water passing through the cooling fins 18 and 19. For this reason, it becomes possible to improve the cooling performance (heat dissipation performance) by the cooling fins 18 and 19 by this turbulent flow.

(Third embodiment)
FIG. 8 is a plan view of the cooling fins 18 and 19 in the present embodiment. As the corrugated cooling fins 18 and 19, in the first embodiment, wave fins having fin peaks extending in a wave shape in a plan view of the cooling fins are used, but in this embodiment, as shown in FIG. Straight fins in which the fin peaks extend linearly in a plan view of the fins are used.

(Other embodiments)
(1) In the above-described embodiment, in the formation of the cooling fins 18 and 19, the brazing material layer is clad in advance on one side of the base material, which is the overlapping surface of the fin portion and the flat plate portion, as the metal plate 50. Although the clad material is used, an uncladded material may be used. In this case, after the metal plate 50 is bent, a flat brazing material is sandwiched between the fin portions 18a and 19a and the flat plate portions 18b and 19b, and the fin portions 18a and 19a and the flat plate portions 18b and 19b are caulked. It may be brazed by heating in a heated state.

  (2) In the above-described embodiment, in the formation of the cooling fins 18 and 19, as shown in FIGS. 5A and 5B, the fin portions 18a and 19a and the flat plate portions 18b and 19b are integrally formed. The fin portions 18a and 19a and the flat plate portions 18b and 19b are overlapped by bending the metal plate 50 at the bent portions 18c and 19c, but the fin portions 18a and 19a and the flat plate portions 18b and 19b are separated. You may form and superimpose both.

  Even in this case, since the fin portions 18a and 19a and the flat plate portions 18b and 19b are brazed, the fillet 51 made of the brazing material is formed at the joint portion between the fin crest and the flat plate portions 18b and 19b. The same effect can be obtained.

  However, from the viewpoint of increasing the productivity of the cooling fins 18 and 19, the fin portions 18a and 19a and the flat plate portion are not necessary because the alignment process between the fin portions 18a and 19a and the flat plate portions 18b and 19b is not necessary. It is preferable to employ a method in which the metal plate 50 integrally formed with 18b and 19b is bent by the bent portions 18c and 19c.

  (3) In the above-described embodiment, the case where the resin mold part 20 is configured by the thermosetting resin mold part 21 and the thermoplastic resin mold part 22 has been described as an example. However, you may comprise all these resin mold parts with a thermosetting resin or both thermoplastic resins. However, in consideration of heat resistance, it is preferable that the portion covering the component such as the semiconductor chip 11 is made of a thermosetting resin, and only the outer edge portion of each unit 10 is replaced so that the power card can be reused. In this case, it is preferable that the outer edge portion is made of a thermoplastic resin so as to be softened at a relatively low temperature.

  (4) In the above-described embodiment, the case where the semiconductor module 1 is applied to the inverter that drives the three-phase motor has been described as an example. However, the semiconductor module 1 of the present invention is not limited to the inverter and may be applied to other devices. May be applied.

  (5) In the above-described embodiment, the cooling water is described as an example of the refrigerant, but other refrigerants may be used.

DESCRIPTION OF SYMBOLS 1 Semiconductor module 10 Unit 11 Semiconductor chip 13, 14 Heat spreader 15 Positive electrode lead 16 Negative electrode lead 17 Control terminal 18, 19 Cooling fin 18a, 19a Fin part 18b, 19b Flat plate part 18c, 19c Bending part 20 Resin mold part 21 Thermosetting resin Mold part 21a Concave part 22 Thermoplastic resin mold part 22c Passage hole 30 Water channel 40 Lid part 41 Pipe lid part 43 Fixing tool 51 Fillet

Claims (5)

A semiconductor chip (11) having a front surface and a back surface and having a semiconductor power element formed thereon;
A first heat spreader (13) connected to the back side of the semiconductor chip (11);
A second heat spreader (14) connected to the surface side of the semiconductor chip (11);
Terminals (15-17) electrically connected to the semiconductor power element;
A part of the terminals (15 to 17) electrically connected to the semiconductor power element is exposed, and the first and second heat spreaders (13, 14) on the opposite side to the semiconductor chip (11). Covering the semiconductor chip (11), the first and second heat spreaders (13, 14), and the terminals (15-17) while exposing the surface, constitutes a part of the refrigerant passage through which the refrigerant flows. A resin mold part (20),
The semiconductor chip (11), the first and second heat spreaders (13, 14), and the terminals (15-17) molded by the resin mold part (20) are used as one unit (10). A semiconductor module in which both ends of the unit (10) are sandwiched between lids (40, 41) and fixed with a fixture (43),
Of the first and second heat spreaders (13, 14), the surface opposite to the semiconductor chip (11) is a flat surface, and insulating films (13b, 14b) covering the flat surface are formed on the flat surface. The corrugated cooling fins (18, 19) having a corrugated cross section are joined via the insulating films (13b, 14b),
The cooling fins (18, 19) include a plurality of fin portions (18a, 19a) having a plurality of fin peaks and the flat plate portions (18b, 19b), and the flat plate portions (18b, 19b) The fin portion side surface and the fin portion (18a, 19a) of the fin portion (18a, 19a) and the fin crest of the flat plate portion side are joined by brazing, and the fin portion of the flat plate portion (18b, 19b) The surface opposite to (18a, 19a) and the insulating film (13b, 14b) are joined by soldering,
A semiconductor module, wherein a fillet (51) made of a brazing material is formed at a joint between the fin portions (18a, 19a) and the flat plate portions (18b, 19b).   The semiconductor module according to claim 1, wherein the fin portions (18 a, 19 a) are wave fins in which the fin crests are arranged in a wave shape in a plan view.   The cooling fins (18, 19) provided in the adjacent units (10) are cooled with respect to one of the wavy fin portions (18a, 19a) of the cooling fins (18, 19). The other wavy fin portion (18a, 19a) of the fins (18, 19) has a planar layout in which a phase is shifted by 180 degrees to form a cross-wave shape. 2. The semiconductor module according to 2. A method for manufacturing a semiconductor module according to any one of claims 1 to 3,
A metal plate (50) in which the fin portions (18a, 19a) and the flat plate portions (18b, 19b) are integrally formed is prepared, and the fin portions (18a, 19a) of the metal plate (50) are prepared. The fin portions (18a, 19a) and the flat plate portions (18b, 19b) are overlapped with each other by bending at bent portions (18c, 19c) between the flat plate portions (18b, 19b). The cooling fin (18, 19) is joined by brazing the surface on the fin portion side of (18b, 19b) and the fin crest on the flat plate portion of the fin portion (18a, 19a). Forming,
A method of manufacturing a semiconductor module, comprising: bonding the flat plate portions (18b, 19b) of the formed cooling fins (18, 19) and the insulating films (13b, 14b) by soldering.   As the metal plate (50), a clad material in which a brazing material is clad on the surface of a base material that is an overlapping surface of the fin portions (18a, 19a) and the flat plate portions (18b, 19b) is used. The method for manufacturing a semiconductor module according to claim 4, wherein:

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