JP2008244238A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device which is configured so that a semiconductor element is cooled from one side and can improve a discharge characteristic of heat generated in the semiconductor element. <P>SOLUTION: In the semiconductor device 10, a plane shape of the semiconductor element 12 is smaller than that of a metallic circuit 13 and the semiconductor element 12 is arranged in the metallic circuit 13. A heat mass 17 has a heat mass body 17a extended to a position opposed to the metallic circuit 13 existing on a position exceeding the peripheral edge 12c of the semiconductor element 12 in a plane view of the semiconductor device 10. A heat conductive part 20 formed of a synthetic resin material and having an insulating property is formed between the lower surface 17c of the heat mass body 17a and the metallic circuit 13, and the heat mass 17 and the metallic circuit 13 are thermally coupled with each other by the heat conductive part 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  According to the present invention, the first coupling surface of the semiconductor element is thermally coupled to one surface of the circuit board, the cooler is coupled to the other surface of the circuit board, and the first coupling surface of the semiconductor element on the side opposite to the first coupling surface. The present invention relates to a semiconductor device in which a heat mass is thermally coupled to two coupling surfaces.

  In a semiconductor device in which a semiconductor element is mounted on a circuit board, for example, there is a technique disclosed in Patent Document 1 as a technique for radiating heat generated in the semiconductor element. As shown in FIG. 6, in an electronic control device 90 (semiconductor device) disclosed in Patent Document 1, a circuit board 91 is disposed in a housing 100 including a lower case 99a and an upper case 99b. In the casing 100, a lid 93 is attached to the surface of the circuit board 91 on which the heat generating element 92 is mounted so as to cover the heat generating element 92. The lid 93 includes a leg portion 94 and a plate portion 95. The leg portion 94 is erected from the periphery of the heat generating element 92 in the circuit board 91. The heat radiating plate portion 95 is connected to the upper portion of the leg portion 94, the lower surface of the plate portion 95 is close to the upper surface of the heating element 92, and the upper surface of the plate portion 95 is close to the inner wall surface of the upper case 99b. . Further, a heat-dissipating gel material 97 is disposed between the upper surface of the plate portion 95 and the inner wall surface of the upper case 99b in the lid 93, and a heat-dissipating gel material 97 is disposed between the lower surface of the plate portion 95 and the heating element 92. A gel material 98 is disposed.

In the electronic control unit 90, the heat generated by the heating element 92 is conducted to the plate portion 95 of the lid 93 through the gel material 98 and further conducted to the upper case 99 b through the gel material 97. The heat conducted to the upper case 99b is radiated from the upper case 99b, and as a result, the heat generating element 92 is radiated. In the electronic control unit 90, heat generated in the heat generating element 92 is radiated to the upper side of the heat generating element 92, and the heat generating element 92 is cooled from one side thereof.
JP 2005-12127 A

  However, in the electronic control device 90 disclosed in Patent Document 1, the heat generated in the heating element 92 is absorbed by the gel material 98 interposed between the heating element 92 and the plate portion 95, and the heat to the plate portion 95 is absorbed. The amount of conduction will decrease. Further, the gel material 97 is also interposed between the plate portion 95 and the upper case 99b, and the heat conducted to the plate portion 95 is absorbed by the gel material 97, and the amount of heat conduction to the upper case 99b is reduced. End up. For this reason, in the electronic control unit 90 of Patent Document 1, the amount of heat generated from the heating element 92 to the upper case 99b is reduced, and the heat dissipation characteristics are low.

  The present invention has been made in view of the above-described conventional problems, and in a semiconductor device in which a semiconductor element is cooled from one side, a semiconductor device capable of improving the heat dissipation characteristics of heat generated in the semiconductor element is provided. It is to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the first coupling surface of the semiconductor element is thermally coupled to one surface of the circuit board and is generated in the semiconductor element on the other surface of the circuit board. A forced cooling type cooler through which heat is conducted is coupled, and further, a heat mass is thermally coupled to a second coupling surface of the semiconductor element opposite to the first coupling surface, The planar shape of the semiconductor element is formed smaller than the planar shape of the circuit board, and the semiconductor element is disposed within one surface of the circuit board, and the heat mass is positioned beyond the edge of the semiconductor element in a plan view of the semiconductor device. A heat mass body extending to face a certain circuit board is provided, and a heat conduction portion made of an insulating material is interposed between the heat mass body and the circuit board, and the heat conduction portion And Tomasu and the circuit board are thermally coupled.

  According to the present invention, the heat mass body is formed so as to face the circuit board without sandwiching the semiconductor element, and the heat conduction portion is interposed between the circuit board and the heat mass body facing the circuit board, so that the heat conduction is achieved. The heat mass and the circuit board were thermally coupled by the part. For this reason, in the semiconductor device, a heat radiation path for conducting heat directly from the semiconductor element to the cooler and a heat radiation path for conducting heat from the heat mass to the cooler through the heat conduction unit and the circuit board are formed. Therefore, the heat dissipation characteristics of the semiconductor device can be improved as compared with the case where only the heat dissipation path that directly conducts heat from the semiconductor element to the cooler is formed.

  According to a second aspect of the present invention, in the semiconductor device according to the first aspect, in the heat mass main body, the length from the position matching the edge of the semiconductor element to the tip of the heat mass main body is the heat mass main body and the circuit board. It is longer than the length between. According to this invention, a circuit board can be located in the area | region of the heat transfer path | route from a heat mass main body, and can be radiated | emitted reliably to a circuit board with the heat dissipation path | route via the heat conductive part.

  According to a third aspect of the present invention, in the semiconductor device according to the first or second aspect, the heat conduction portion covers the entire heat mass. According to this invention, it is possible to dissipate heat from the heat conduction portion that covers the side surface of the heat mass and the side opposite to the bonding side to the semiconductor element in the heat mass. And since the whole heat mass is covered with the heat conduction part, a cooler cannot be provided on the opposite side of the heat mass to the semiconductor element coupling side, and the semiconductor device has a cooler only on the other surface of the circuit board. It is a one-side cooling type coupled to Even in such a one-side cooling type semiconductor device, it is possible to improve the heat dissipation characteristics of the semiconductor device by making it possible to form two heat dissipation paths for the semiconductor element, and to ensure that the semiconductor element is overheated. Can be suppressed.

  According to a fourth aspect of the present invention, in the semiconductor device according to any one of the first to third aspects, the thickness of the heat mass body is set to 1 to 20 mm. According to the present invention, the heat mass body is too thin and the heat capacity of the heat mass is insufficient, so that the heat absorption function is not sufficiently exhibited, or the heat mass body is too thick and the physique of the semiconductor device is enlarged. it can.

  According to a fifth aspect of the present invention, in the semiconductor device according to any one of the first to fourth aspects, the heat mass is joined to a second bonding surface of the semiconductor element via solder. A leg portion is formed, the planar shape of the leg portion is formed smaller than the planar shape of the second coupling surface, and the leg portion is joined in the second coupling surface.

  According to the present invention, the legs of the heat mass are joined so as to be within the range of the second coupling surface of the semiconductor element. For this reason, it can prevent that the periphery of a semiconductor element and the 2nd bonding surface of a semiconductor element are electrically connected via a heat mass.

  According to a sixth aspect of the present invention, in the semiconductor device according to any one of the first to fifth aspects, the planar shape of the heat mass body is formed larger than the planar shape of the second coupling surface of the semiconductor element. The heat mass body is formed so as to face the circuit board at a position beyond the entire periphery of the semiconductor element.

  According to this invention, the heat dissipation path toward the heat sink can be formed around the entire heat mass body, and the heat dissipation characteristics can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, in the semiconductor device which cooled the semiconductor element from the one side, the heat dissipation characteristic of the heat which generate | occur | produced in the semiconductor element can be improved.

  Hereinafter, an embodiment in which the present invention is embodied in a semiconductor device (semiconductor module) mounted on a vehicle and used will be described with reference to FIGS. 1 and 2. 1 and 2 schematically show the structure of the semiconductor device. For the sake of illustration, in order to exaggerate some dimensions and make them easy to understand, the width, length, The ratio of dimensions such as thickness is different from the actual ratio.

  As shown in FIG. 1, the semiconductor device 10 includes an insulated circuit board 11 as a circuit board. The insulated circuit board 11 includes a ceramic substrate 14 having a metal circuit 13 on the front surface (upper surface) and a metal plate 16 on the back surface (lower surface). The first coupling surface 12a of the semiconductor element 12 is bonded to the metal circuit 13 which is one surface of the insulating circuit substrate 11 via the solder layer H1, and the first bonding surface of the semiconductor element 12 is bonded to one surface of the insulating circuit substrate 11. 12a is thermally coupled. Although a plurality of semiconductor elements 12 are joined to the metal circuit 13, only one is shown for convenience of illustration. The planar shape of the semiconductor element 12 is smaller than the planar shape of the metal circuit 13, the semiconductor element 12 is disposed in the plane of the metal circuit 13, and the metal circuit 13 is located all around the semiconductor element 12. A metal heat sink 15 as a cooler is joined to the metal plate 16 on the other surface of the insulating circuit board 11, and the heat sink 15 is thermally coupled to the other surface of the insulating circuit board 11.

  The heat sink 15 is formed in a plate shape and includes a refrigerant flow path 15a through which a cooling medium flows. The cooling capacity of the heat sink 15 is such that when the semiconductor element 12 is in a steady heat generation state (normal state), heat generated in the semiconductor element 12 is conducted to the heat sink 15 via the insulating circuit board 11 and is smoothly removed. Is set. The heat sink 15 functions as a forced cooling type cooler in which heat generated in the semiconductor element 12 is conducted through the insulating circuit board 11.

  As the semiconductor element 12, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET, or a diode is used. The metal circuit 13 is made of, for example, aluminum or copper. Also, the semiconductor element 12 is formed with a smooth surface on both sides. The ceramic substrate 14 is made of, for example, aluminum nitride, alumina, silicon nitride, or the like. The heat sink 15 is formed of aluminum metal, copper or the like. An aluminum-based metal means aluminum or an aluminum alloy. The metal plate 16 functions as a bonding layer for bonding the ceramic substrate 14 and the heat sink 15 and is formed of, for example, aluminum or copper.

  In the heat sink 15, the refrigerant flow path 15a includes an inlet portion and an outlet portion (not shown), and the inlet portion and the outlet portion are formed so as to be connectable to a refrigerant circulation path equipped in the vehicle. Although a plurality of insulating circuit boards 11 and semiconductor elements 12 are mounted on the heat sink 15, only one is shown for convenience of illustration.

  In the semiconductor element 12, the second bonding surface 12b opposite to the first bonding surface 12a temporarily absorbs heat generated in the semiconductor element 12, and then releases heat mass 17 through the solder layer H2. Are joined. As a material of the heat mass 17, a metal having a melting point higher than that of the solder (solder layer H2) for joining the semiconductor element 12 and the heat mass 17 is preferable.

  The semiconductor device 10 includes a heat mass 17 that is thermally coupled to the second coupling surface 12 b of the semiconductor element 12. The heat mass 17 also serves as an electrode of the semiconductor element 12. When the semiconductor element 12 is an IGBT, the second coupling surface 12b becomes an emitter, and the heat mass 17 becomes an emitter electrode. When the semiconductor element 12 is a MOSFET, the second coupling surface 12b is a source and the heat mass 17 is a source electrode. Further, when the semiconductor element 12 is a diode, the second coupling surface 12b becomes an anode and the heat mass 17 becomes an anode electrode.

  When the heat capacity of the heat mass 17 is larger than that of the steady heat generation state from the semiconductor element 12 due to overload or the like, and the cooling function by the heat sink 15 is insufficient, a part of the heat generated in the semiconductor element 12 is temporarily stored. It is set to a value necessary to suppress the semiconductor element 12 from being absorbed and being overheated. For example, in the case where the semiconductor device 10 is an inverter used for controlling a driving motor of a hybrid vehicle, when sudden acceleration or sudden stop is caused from a steady operation state, the heat generation from the semiconductor element 12 is rated in a short time of less than 1 second. 3 to 5 times as much heat loss. In this embodiment, the heat capacity of the heat mass 17 is set so that the temperature of the semiconductor element 12 does not exceed the upper limit of the operating temperature. The excessive heat loss is generated in the case of a sudden stop because a large current flows because the regenerative operation is performed.

  The heat mass 17 includes a heat mass main body 17a having a planar shape larger than that of the semiconductor element 12 (see FIG. 2), and a single leg portion 17b extending from the heat mass main body 17a. The heat mass main body 17a is formed in a plate shape having a rectangular shape in plan view, and the thickness D of the heat mass main body 17a excluding the leg portions 17b is constant along the length direction of the heat mass main body 17a. The thickness D of the heat mass body 17a is preferably set to 1 to 20 mm. When the thickness D of the heat mass body 17a is less than 1 mm, when the heat capacity of the heat mass 17 set as described above, that is, when the cooling function by the heat sink 15 is insufficient, a part of the heat generated in the semiconductor element 12 is temporarily Therefore, it is not preferable because the heat capacity necessary for suppressing the semiconductor element 12 from being excessively absorbed and suppressing the semiconductor element 12 from being overheated cannot be secured. On the other hand, when the thickness D of the heat mass main body 17a exceeds 20 mm, a sufficient heat capacity to function as the heat mass 17 can be secured, but the physique of the heat mass 17 is undesirably enlarged.

  The leg portion 17b of the heat mass 17 is formed in a square shape in cross-section perpendicular to the axial direction (see FIG. 2), and the cross-sectional shape of the leg portion 17b is smaller than the planar shape of the semiconductor element 12. The heat mass 17 is joined to the second coupling surface 12b via the solder layer H2 so that the leg portion 17b is within the range of the second coupling surface 12b of the semiconductor element 12. In other words, the second coupling surface 12b of the semiconductor element 12 is positioned around the leg 17b. For this reason, the heat mass main body 17a is not directly joined to the second coupling surface 12b, and the second coupling surface 12b and the peripheral edge 12c of the semiconductor element 12 are not electrically connected by the heat mass main body 17a.

  As shown in FIG. 2, in a state where the heat mass 17 is bonded to the semiconductor element 12, the heat mass body 17 a covers the entire semiconductor element 12 in a plan view of the semiconductor device 10, and in the plan view of the semiconductor device 10, the heat mass body 17 a is The semiconductor element 12 extends to a position beyond the peripheral edge 12c. For this reason, as shown in FIG. 1, almost the entire lower surface 17 c of the heat mass body 17 a faces the metal circuit 13 on the insulating circuit substrate 11 without sandwiching the semiconductor element 12. In this embodiment, the opposing surface which opposes the metal circuit 13 which is one surface of the insulated circuit board 11 is formed by the lower surface 17c of the heat mass main body 17a. The heat mass 17 is formed so that the lower surface 17 c of the heat mass body 17 a is parallel to the metal circuit 13.

  A straight line passing through the peripheral edge 12 c of the semiconductor element 12 and extending in the thickness direction of the semiconductor element 12 is defined as a straight line K. When a position where the straight line K intersects the lower surface 17c is defined as an intersection P, the intersection P is a position that matches the peripheral edge 12c of the semiconductor element 12 on the lower surface 17c. On the lower surface 17c, the length from the position (intersection P) matching the peripheral edge 12c (edge) of the semiconductor element 12 to the tip of the heat mass body 17a is set to L1. The length L1 is longer than the length L2 between the lower surface 17c of the heat mass body 17a and the metal circuit 13.

  In the semiconductor device 10, the heat transfer path from the tip of the heat mass main body 17 a of the heat absorbed by the heat mass 17 from the semiconductor element 12 has the lower ends of the heat mass main body 17 a as tops and an angle of 45 ° with the surface of the metal circuit 13. A trapezoidal shape whose side surface (inclined surface) is formed, and a straight line N1 indicated by a two-dot chain line in FIG. 1 represents the boundary of the entire heat transfer path. A straight line N2 indicated by a two-dot chain line indicates a boundary of the heat transfer path that contributes particularly high to heat transfer. The length L1 is set longer than the length L2 so that the insulating circuit board 11 faces the region of the heat transfer path indicated by the straight line N2.

  In the semiconductor device 10, the entire upper side from the heat sink 15 is covered with a heat conducting portion 20 made of a synthetic resin material. The heat conducting unit 20 is made of an insulating material, and the material is preferably a synthetic resin having high heat conductivity. Examples thereof include a resin material obtained by mixing an epoxy resin or a filler with a resin.

  The heat conduction unit 20 covers the entire heat mass 17, that is, the heat mass main body 17a and the leg portion 17b, and the heat conduction unit 20 is in contact with the side surface of the heat mass main body 17a and the side surface of the leg portion 17b. The heat conducting unit 20 covers the insulating circuit board 11 (metal circuit 13) and is in contact with the metal circuit 13. And the synthetic resin material which forms the heat conduction part 20 is filled with no gap between the lower surface 17c in the heat mass body 17a and the metal circuit 13 in the insulating circuit board 11, and the heat conduction part 20 is applied to the lower surface 17c and the metal circuit 13. In contact. For this reason, the lower surface 17c of the heat mass body 17a and the metal circuit 13 (insulating circuit board 11) are thermally coupled via the heat conducting unit 20.

  Next, the operation of the semiconductor device 10 configured as described above will be described. The semiconductor device 10 is mounted on a hybrid vehicle as a vehicle, and is used in a state where a heat sink 15 communicates with a refrigerant circulation path (not shown) via a pipe. A pump and a radiator are provided in the refrigerant circulation path, and the radiator includes a fan that is rotated by a motor so that heat is efficiently radiated from the radiator. For example, water is used as the cooling medium.

  When the semiconductor element 12 mounted on the semiconductor device 10 is driven, heat is generated from the semiconductor element 12. In the steady operation state (steady heat generation state), the heat generated from the semiconductor element 12 is conducted to the heat sink 15 through the solder layer H1 and the insulating circuit substrate 11. That is, the heat generated from the semiconductor element 12 is conducted to the heat sink 15 through the heat dissipation path Y1 via the solder layer H1 and the insulating circuit board 11. The heat conducted to the heat sink 15 is conducted and taken away by the cooling medium flowing through the refrigerant flow path 15 a, and the heat is radiated by the heat sink 15. That is, since the heat sink 15 is forcibly cooled by the cooling medium flowing through the refrigerant flow path 15 a, the heat generated in the semiconductor element 12 is efficiently removed via the heat sink 15.

  When sudden acceleration or sudden stop is performed from the steady operation state, the heat generation from the semiconductor element 12 rapidly increases, and a heat loss of 3 to 5 times the rating is generated in a short time of 1 second or less. This unsteady high heat generation cannot be dealt with only by forced cooling by the heat sink 15. However, since the heat mass 17 is soldered to the semiconductor element 12, heat that cannot be removed by the heat sink 15 is temporarily absorbed by the heat mass 17.

  Further, when the heat mass 17 is in a heat saturation state, the heat absorbed by the heat mass 17 is mainly conducted from the lower surface 17c of the heat mass main body 17a to the heat conducting unit 20. The heat conducted to the heat conducting unit 20 is conducted to the heat sink 15 via the insulating circuit board 11. That is, the heat absorbed by the heat mass 17 is conducted to the heat sink 15 through the heat dissipation path Y <b> 2 via the heat conducting unit 20 and the insulating circuit substrate 11. The heat conducted to the heat sink 15 is conducted to the cooling medium flowing through the refrigerant flow path 15 a and taken away, and is radiated by the heat sink 15. That is, since the heat sink 15 is forcibly cooled by the cooling medium flowing through the refrigerant flow path 15a, the heat absorbed by the heat mass 17 is efficiently removed.

  Therefore, in the semiconductor device 10, in addition to the heat conducted directly from the semiconductor element 12 to the heat sink 15 via the heat dissipation path Y 1, the heat sink 15 passes from the heat mass 17 via the heat dissipation path Y 2 to the heat sink 15 and the insulating circuit substrate 11. Heat conducted to the heat sink 15 is carried away by the cooling medium flowing through the heat sink 15. Furthermore, since the heat conducting unit 20 is also in contact with the tip and top surface of the heat mass main body 17a (the side opposite to the coupling side to the semiconductor element 12 in the heat mass 17), heat is radiated through the heat conducting unit 20. When the semiconductor device 10 returns to the steady operation state, the heat of the heat mass 17 is conducted to the heat sink 15 through the semiconductor element 12 and the insulating circuit substrate 11, and the heat mass 17 returns to the original state.

According to the above embodiment, the following effects can be obtained.
(1) The heat mass body 17a in the heat mass 17 is formed such that the lower surface 17c (opposing surface) faces the metal circuit 13 (one surface of the insulating circuit board 11) without sandwiching the semiconductor element 12, and the heat mass body 17a and the metal circuit are formed. The heat conduction unit 20 is interposed between the heat mass body 17a and the metal circuit 13 and is thermally coupled. Therefore, in the semiconductor device 10, a heat dissipation path Y 1 that conducts heat directly from the semiconductor element 12 to the heat sink 15 and a heat dissipation path that conducts heat from the heat mass 17 to the heat sink 15 via the heat conducting unit 20 and the insulating circuit substrate 11. Y2 is formed. Therefore, the heat dissipation characteristics in the semiconductor device 10 can be improved as compared with the case where only the heat dissipation path Y1 that conducts heat directly from the semiconductor element 12 to the heat sink 15 is formed.

  (2) Since the heat conduction part 20 is interposed between the heat mass body 17a and the metal circuit 13, a heat radiation path Y2 extending from the heat mass body 17a to the heat sink 15 via the heat conduction part 20 and the insulating circuit board 11 is formed. . Even when the heat mass 17 is in a heat saturation state, the heat absorbed by the heat mass 17 can be passed through the heat dissipation path Y <b> 2 to conduct heat to the heat sink 15, and can be dissipated from the heat sink 15. Therefore, the semiconductor element 12 is suppressed from being overheated.

  (3) On the lower surface 17c of the heat mass main body 17a, the length L1 from the position (intersection P) matching the peripheral edge 12c of the semiconductor element 12 to the tip of the heat mass main body 17a is between the lower surface 17c of the heat mass main body 17a and the metal circuit 13 It is longer than the length L2. For this reason, it is possible to allow the insulating circuit board 11 to face the region of the heat transfer path that contributes particularly high to heat transfer among the heat transfer paths from the heat mass body 17a, and the heat absorbed by the heat mass 17 is the heat dissipation path Y2. Heat can be conducted to the heat sink 15.

  (4) The thickness of the heat mass body 17a is set to 1 to 20 mm. For this reason, the heat mass main body 17a is too thin and the heat capacity of the heat mass 17 is insufficient, so that the heat absorption function is not sufficiently exhibited, or the heat mass main body 17a is too thick and the size of the semiconductor device 10 is increased. Can do.

  (5) The heat conducting unit 20 covers the entire heat mass 17. For this reason, it is possible to radiate heat not only from the heat conducted to the heat sink 15 through the heat radiation path Y2, but also from the side surface and the upper surface of the heat mass body 17a. The semiconductor device 10 is a one-side cooling type that includes the heat sink 15 as a cooler. Even in such a one-side cooling type semiconductor device 10, it is possible to improve the heat dissipation characteristics of the semiconductor device 10 by making it possible to form the two heat dissipation paths Y <b> 1 and Y <b> 2 and to ensure that the semiconductor element 12 is overheated. Can be suppressed.

  (6) In the heat mass 17, the leg portion 17 b is joined so as to be within the range of the second coupling surface 12 b of the semiconductor element 12. For this reason, it is possible to prevent the peripheral edge 12c of the semiconductor element 12 and the second coupling surface 12b of the semiconductor element 12 from being electrically connected via the heat mass body 17a.

  (7) The planar shape of the heat mass body 17a is formed to be larger than the planar shape of the second coupling surface 12b of the semiconductor element 12, and the heat circuit body 17a has a lower surface 17c in a position beyond the entire peripheral edge 12c of the semiconductor element 12. It is formed so as to face. And the heat conduction part 20 is provided over the perimeter of the heat mass main body 17a. For this reason, the heat dissipation path Y2 toward the heat sink 15 can be formed on the entire circumference of the heat mass body 17a, and the heat dissipation characteristics can be improved.

  (8) The heat conducting unit 20 is made of a synthetic resin material having insulating properties. The melted synthetic resin material is filled between the heat mass main body 17a and the insulating circuit board 11 to form the heat conducting portion 20. For this reason, the heat conduction part 20 can be made to contact the heat mass main body 17a and the metal circuit 13 reliably. And, for example, it is assumed that the heat conduction part 20 is molded into a solid state, and the heat mass body 17a is compared with the case where the solid heat conduction part 20 is fitted between the heat mass body 17a and the insulating circuit board 11. The thermal coupling with the metal circuit 13 can be improved.

In addition, you may change the said embodiment as follows.
As shown in FIG. 3, the heat conducting unit 20 is not provided so as to cover the entire heat mass 17, but between one surface (metal circuit 13) of the insulating circuit substrate 11 and the lower surface 17 c (opposing surface) of the heat mass body 17 a. It may be provided so as to be interposed only between the two. Alternatively, although not shown, the heat conducting unit 20 is provided on the insulating circuit board 11 side (upper side) than the heat sink 15 and on the side of the insulating circuit board 11, the solder layer H1, the semiconductor element 12, the solder layer H2, and the heat mass 17. The upper surface of the heat mass 17 may be provided so as not to be covered.

  As shown in FIG. 4, in the heat mass 17, the heat mass main body 17 a may be formed so as to be inclined so that the lower surface 17 c approaches one surface (metal circuit 13) of the insulating circuit substrate 11 toward the tip. If comprised in this way, the space | interval of the one surface (metal circuit 13) of the insulated circuit board 11 and the lower surface 17c of the heat mass main body 17a will become short gradually, and it will become easy to conduct heat from the heat mass 17 to the insulated circuit board 11. In this case, the length L2 from the lower surface 17c of the heat mass body 17a to the metal circuit 13 is the length from the lower end to the metal circuit 13 at the tip of the heat mass body 17a. The thickness D of the heat mass 17 is the thickness at the tip of the heat mass main body 17a.

  As shown in FIG. 5, the heat mass body 17 a is formed to extend from the second coupling surface 12 b of the semiconductor element 12 beyond a part of the peripheral edge 12 c of the semiconductor element 12 in a plan view of the semiconductor device 10. 17a may not exceed the entire circumference of the peripheral edge 12c of the semiconductor element 12. That is, the heat conduction part 20 is interposed between the heat mass body 17a and the metal circuit 13 without the semiconductor element 12, and the heat mass body 17a and the metal circuit 13 are thermally coupled by the heat conduction part 20. If present, the shape of the heat mass body 17a may be arbitrarily changed. In FIG. 5, the heat conducting unit 20 is not provided so as to cover the entire heat mass 17, and is interposed only between one surface (metal circuit 13) of the insulating circuit board 11 and the lower surface 17c (opposing surface) of the heat mass body 17a. It is provided to be. Note that the heat conducting unit 20 may be provided on the entire upper side of the heat sink 15 as in the embodiment, and may be provided so as to cover the entire heat mass 17.

A plurality of heat masses 17 may be bonded to one semiconductor element 12. In this case, thermal stress is relieved by dividing the heat mass 17.
The heat sink 15 may be a forced cooling type cooler, and the cooling medium flowing through the heat sink 15 is not limited to water, and may be other liquid or gas such as air, for example. Further, it may be a boiling cooling type cooler.

  Not only the structure in which the single metal circuit 13 is formed on the insulating circuit board 11 but also a structure in which a plurality of metal circuits 13 are formed and the semiconductor element 12 is joined to each metal circuit 13 may be employed. In this case, the heat mass 17 is bonded to each semiconductor element 12, and the heat conducting unit 20 is interposed between the lower surface 17 c of each heat mass 17 and the metal circuit 13 facing the lower surface 17 c.

  The semiconductor device 10 may be applied not only to in-vehicle use but also to other uses.

Sectional drawing which shows the semiconductor device of embodiment schematically. FIG. 2 is a plan view schematically showing the semiconductor device of the embodiment. FIG. 6 is a cross-sectional view schematically showing another example of a semiconductor device. FIG. 6 is a cross-sectional view schematically showing another example of a semiconductor device. FIG. 6 is a plan view schematically showing another example of a semiconductor device. Sectional drawing which shows the electronic control apparatus of background art.

Explanation of symbols

  D ... thickness, H2 ... solder layer as solder, L1, L2 ... length, 10 ... semiconductor device, 11 ... insulated circuit board as circuit board, 12 ... semiconductor element, 12a ... first coupling surface, 12b ... second Bonding surface, 12c ... periphery as edge, 13 ... metal circuit forming one surface of circuit board, 15 ... heat sink as cooler, 16 ... metal plate forming other surface of circuit board, 17 ... heat mass, 17a ... heat mass Main body, 17b ... leg part, 20 ... heat conduction part.

Claims (6)

A first cooling surface of the semiconductor element is thermally coupled to one surface of the circuit board and a forced cooling type cooler is coupled to the other surface of the circuit board to conduct heat generated in the semiconductor element. A semiconductor device in which a heat mass is thermally coupled to a second coupling surface opposite to the first coupling surface in the semiconductor element,
The planar shape of the semiconductor element is formed smaller than the planar shape of the circuit board, and the semiconductor element is disposed within one surface of the circuit board, and the heat mass is positioned beyond the edge of the semiconductor element in a plan view of the semiconductor device. A heat mass body that extends to face a certain circuit board is provided, and a heat conduction part made of an insulating material is interposed between the heat mass body and the circuit board, and the heat mass and the circuit board are heated by the heat conduction part. Semiconductor device that is physically coupled.   2. The semiconductor device according to claim 1, wherein in the heat mass main body, a length from a position matching the edge of the semiconductor element to a tip of the heat mass main body is longer than a length between the heat mass main body and the circuit board.   The semiconductor device according to claim 1, wherein the heat conducting portion covers the entire heat mass.   The thickness of the said heat mass main body is a semiconductor device as described in any one of Claims 1-3 set to 1-20 mm.   The heat mass is formed with a leg that is joined to the second coupling surface of the semiconductor element via solder, and the planar shape of the leg is smaller than the planar shape of the second coupling surface and the leg. The semiconductor device according to claim 1, wherein the semiconductor device is joined in a second coupling plane.   The planar shape of the heat mass body is formed larger than the planar shape of the second coupling surface in the semiconductor element, and the heat mass body is formed to face the circuit board located at a position beyond the entire periphery of the semiconductor element. The semiconductor device according to claim 5.

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