Power module

Abstract

A power module (101) is provided with: a first substrate (1A) having a first surface (1A1); a first power semiconductor element (2A) mounted on the first surface; a printed circuit board (4) having a first facing portion (4A) disposed so as to overlap the first surface of the first substrate in a first direction (Z) orthogonal to the first surface; and a first conductor pillar (3A) electrically connecting the first power semiconductor element and the first facing portion. In the first facing portion, a first recess (4C) is formed that accommodates the first power semiconductor element and the first conductor pillar therein.

Description

Technical Field

[0001] The present disclosure relates to a power module. Background Art

[0002] Power modules including vertical power semiconductor elements are widely used as power conversion devices in a wide range of fields, including industrial equipment, automobiles, and railways.

[0003] In a typical power module, electrodes of a power semiconductor element are connected to one end of a lead frame serving as an external terminal via bonding wires, and the power semiconductor element, the one end of the lead frame, and the bonding wires are sealed with resin.

[0004] Meanwhile, Japanese Patent Application Laid-Open No. 2009-64852 (Patent Document 1) discloses a semiconductor device in which a main electrode of a semiconductor element mounted on an insulating substrate and a metal foil of a printed circuit board arranged above the semiconductor element are electrically connected via a plurality of post electrodes.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-64852 Summary of the Invention

[0008] In recent years, with the advancement in performance, size, and weight reduction of devices equipped with power modules, in addition to the previously required increases in rated voltage and rated current and expansion of the operating temperature range of power modules, there has also been an increasing demand for reduced wiring inductance, miniaturization, and thinning associated with high-speed switching operations.

[0009] However, in conventional power modules, there are structural limitations on shortening the length between the power semiconductor element electrode and the other end of the lead frame, making it difficult to fully reduce wiring inductance. Furthermore, in conventional power modules, the power semiconductor element electrode and the lead frame end, connected via bonding wires, must be spaced apart when viewed from above, thus limiting their miniaturization when viewed from above.

[0010] Furthermore, in the semiconductor device described in Patent Document 1, the insulating substrate, the semiconductor element, the post electrodes, and the printed circuit board are arranged side by side in their respective thickness directions, so there is a structural limit to thinning.

[0011] A main object of the present disclosure is to provide a power module that achieves reduction in wiring inductance associated with high-speed switching operation, miniaturization, and thickness reduction compared to conventional power modules.

[0012] The present disclosure provides a power module comprising: a first substrate having a first surface; a first power semiconductor element mounted on the first surface; a printed circuit board having a first facing portion arranged to overlap the first surface of the first substrate in a first direction perpendicular to the first surface; and a first conductive post electrically connecting the first power semiconductor element to the first facing portion. A first recess is formed in the first facing portion, which accommodates the first power semiconductor element and the first conductive post.

[0013] According to the present disclosure, it is possible to provide a power module that can simultaneously achieve reduction in wiring inductance accompanying high-speed switching operation, miniaturization, and thickness reduction compared to conventional power modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a perspective plan view showing the power module according to the first embodiment.

[0015] Figure 2 It shows Figure 1 A bottom perspective view of the power module is shown.

[0016] Figure 3 It is from Figure 1 The cross-sectional view is observed along the arrow III-III.

[0017] Figure 4 Is used to illustrate Figure 1 A cross-sectional view showing one process step of a method for manufacturing a power module.

[0018] Figure 5 This is a perspective plan view showing a modified example of the power module according to the first embodiment.

[0019] Figure 6 Is used to illustrate Figure 5 A cross-sectional view showing one process step of a method for manufacturing a power module.

[0020] Figure 7 This is a perspective plan view showing a power module according to the second embodiment.

[0021] Figure 8 It shows Figure 7 A bottom perspective view of the power module is shown.

[0022] Figure 9 It is from Figure 7 The cross-sectional view is observed by arrows IX-IX.

[0023] Figure 10 Is used to illustrate Figure 7 A cross-sectional view showing one process step of a method for manufacturing a power module.

[0024] Figure 11This is a cross-sectional view showing a power module according to the third embodiment.

[0025] Figure 12 Is used to illustrate Figure 11 The power module shown is a cross-sectional view of a semiconductor package.

[0026] Figure 13 This is a cross-sectional view showing a power module according to a fourth embodiment.

[0027] Figure 14 This is a cross-sectional view showing a modified example of the power module according to the fourth embodiment.

[0028] Figure 15 This is a cross-sectional view showing a power module according to the fifth embodiment.

[0029] Figure 16 This is a cross-sectional view showing a power module according to the sixth embodiment.

[0030] Figure 17 This is a cross-sectional view showing a modified example of the power module according to the sixth embodiment.

[0031] Figure 18 This is a cross-sectional view showing a power module according to the seventh embodiment.

[0032] Figure 19 This is a cross-sectional view showing a power module according to the eighth embodiment.

[0033] Figure 20 It is a perspective plan view showing a power module according to Comparative Example 1.

[0034] Figure 21 It shows Figure 20 The cross-sectional view of Comparative Example 1 is shown.

[0035] Figure 22 It is a perspective plan view showing a power module according to Comparative Example 2.

[0036] Figure 23 It shows Figure 22 The cross-sectional view of Comparative Example 2 is shown.

[0037] Figure 24 It is a perspective plan view showing a power module according to Comparative Example 3.

[0038] Figure 25 It shows Figure 24 The cross-sectional view of Comparative Example 3 is shown.

[0039] Figure 26 It is a perspective plan view showing a power module according to Comparative Example 4.

[0040] Figure 27 It shows Figure 26 The cross-sectional view of Comparative Example 4 is shown. DETAILED DESCRIPTION

[0041] Hereinafter, the embodiment of the present disclosure will be described with reference to the accompanying drawings. In addition, the same or corresponding parts will be denoted by the same reference numerals, and repeated description will not be repeated.

[0042] Implementation method 1.

[0043] <Power Module Structure>

[0044] like Figure 1 as well as Figure 2 As shown, the power module 101 according to the first embodiment includes a first insulating substrate 1A (first substrate), a second insulating substrate 1B (second substrate), a first power semiconductor element 2A, a second power semiconductor element 2B, a plurality of first conductive posts 3A, a plurality of second conductive posts 3B, and a printed circuit board 4.

[0045] The first insulating substrate 1A has a first surface 1A1 on which the first power semiconductor element 2A is mounted. In this specification, the direction perpendicular to the first surface 1A1 is referred to as the first direction Z. The first insulating substrate 1A includes a base 10, a first conductor layer 11, and a second conductor layer 12. The first conductor layer 11 and the second conductor layer 12 are arranged in the first direction Z so as to sandwich the base 10. Each of the first conductor layer 11 and the second conductor layer 12 is bonded to the base 10, for example. The first surface 1A1 is formed by the surface of the first conductor layer 11 of the first insulating substrate 1A opposite to the surface bonded to the base 10.

[0046] The material constituting the substrate 10 may be any material having electrical insulation properties. The substrate 10 is, for example, a ceramic plate. The material constituting the first conductive layer 11 and the second conductive layer 12 may be any material having electrical conductivity, for example, a metal material.

[0047] The second insulating substrate 1B has a second surface 1B1 on which a second power semiconductor element 2B is mounted. The second insulating substrate 1B has, for example, the same structure as the first insulating substrate 1A. The second insulating substrate 1B includes a base 10, a first conductive layer 11, and a second conductive layer 12. The second surface 1B1 is formed by the surface of the first conductive layer 11 of the second insulating substrate 1B opposite to the surface bonded to the base 10.

[0048] The first insulating substrate 1A and the second insulating substrate 1B are arranged side by side with each other in a first direction along the first surface 1A1. In the power module 101, the second surface 1B1 faces the same side as the first surface 1A1.

[0049] The first power semiconductor element 2A and the second power semiconductor element 2B are, for example, vertical power semiconductor elements. The first power semiconductor element 2A and the second power semiconductor element 2B are, for example, IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), bipolar transistors, or freewheeling diodes. The first power semiconductor element 2A and the second power semiconductor element 2B are, for example, semiconductor elements of the same type. Alternatively, the first power semiconductor element 2A and the second power semiconductor element 2B may be semiconductor elements of different types.

[0050] The first power semiconductor element 2A has a back surface facing the first insulating substrate 1A in the first direction Z, and a front surface located opposite the back surface and facing the printed circuit board 4 in the first direction Z. A back electrode (not shown) is formed on the back surface of the first power semiconductor element 2A. The back electrode is bonded to the first conductor layer 11 of the first insulating substrate 1A via a bonding material 5. A main electrode 21A and a control electrode 22A are formed on the front surface of the first power semiconductor element 2A. The main electrode 21A and the control electrode 22A of the first power semiconductor element 2A are each electrically connected to a first conductor post 3A. The main electrode 21A is electrically connected to the first wiring layer 41 of the printed circuit board 4, described later, via the first conductor post 3A. The control electrode 22A is electrically connected to the first wiring layer 41 of the printed circuit board 4, described later, via the first conductor post 3A.

[0051] The second power semiconductor element 2B has a back surface facing the second insulating substrate 1B in the first direction Z, and a front surface located opposite the back surface and facing the printed circuit board 4 in the first direction Z. A back electrode (not shown) is formed on the back surface of the second power semiconductor element 2B. The back electrode is bonded to the first conductor layer 11 of the second insulating substrate 1B via a bonding material 5. For example, a main electrode 21B and a control electrode 22B are formed on the front surface of the second power semiconductor element 2B. The main electrode 21B and the control electrode 22B of the second power semiconductor element 2B are each electrically connected to a second conductor post 3B. The main electrode 21B is electrically connected to the first wiring layer 41 of the printed circuit board 4, described later, via the second conductor post 3B. The control electrode 22B is electrically connected to the first wiring layer 41 of the printed circuit board 4, described later, via the second conductor post 3B.

[0052] Each of the plurality of first conductive posts 3A and the plurality of second conductive posts 3B is a columnar body extending along the first direction Z. The material constituting each of the plurality of first conductive posts 3A and the plurality of second conductive posts 3B may be any material having conductivity.

[0053] One end of each of the plurality of first conductive posts 3A in the first direction Z is bonded to the main electrode 21A or the control electrode 22A of the first power semiconductor element 2A via a bonding material (not shown) such as solder. The other end of each of the plurality of first conductive posts 3A in the first direction Z is bonded to a first wiring layer 41 of the printed circuit board 4, described later, via a bonding material (not shown) such as solder.

[0054] One end of each of the plurality of second conductive posts 3B in the first direction Z is bonded to the main electrode 21B or the control electrode 22B of the second power semiconductor element 2B via a bonding material (not shown) such as solder. The other end of each of the plurality of second conductive posts 3B in the first direction Z is bonded to the first wiring layer 41 of the printed circuit board 4, described later, via a bonding material (not shown) such as solder.

[0055] The printed circuit board 4 includes a first wiring layer 41, a second wiring layer 42, an insulator layer 44, a through-hole 45, a first protective layer 46, and a second protective layer 47. The first protective layer 46, the first wiring layer 41, the insulator layer 44, the second wiring layer 42, and the second protective layer 47 are stacked in the order described above in the first direction Z. The first wiring layer 41 is arranged at intervals on the same plane perpendicular to the first direction Z and includes a plurality of patterns that are electrically isolated from each other. The patterns of the first wiring layer 41 are formed by patterning the same conductive layer and are electrically isolated from each other. The second wiring layer 42 is arranged at intervals on the same plane perpendicular to the first direction Z and includes a plurality of patterns that are electrically isolated from each other. The patterns of the second wiring layer 42 are formed by patterning the same conductive layer. The first wiring layer 41 and the second wiring layer 42 are electrically connected via the through-hole 45. The first protective layer 46 and the second protective layer 47 are used to protect the surfaces of the first wiring layer 41 and the second wiring layer 42. The through hole 45 is formed, for example, by burying the entire through hole that penetrates the insulating layer 44. The through hole 45 is, for example, a metal material pressed into the through hole of the insulating layer 44. In addition, the through hole 45 can also be a metal film formed by plating on the wall surface of the through hole of the insulating layer 44. The first protective layer 46 and the second protective layer 47 are, for example, resist layers. The first protective layer 46 includes a portion included in the first opposing portion 4A and a portion included in the second opposing portion 4B, and is formed so that the two portions are connected in the second direction Y and the third direction X. The second protective layer 47 is arranged around the first recess 4C when viewed from above.

[0056] The printed circuit board 4 includes a first opposing portion 4A arranged to overlap with the first surface 1A1 of the first insulating substrate 1A in the first direction Z, and a second opposing portion 4B arranged to overlap with the second surface 1B1 of the second insulating substrate 1B in the first direction Z. The first opposing portion 4A and the second opposing portion 4B are arranged side by side in the second direction Y.

[0057] The first opposing portion 4A includes a portion of each of the first wiring layer 41, the second wiring layer 42, the insulator layer 44, the first protective layer 46, and the second protective layer 47. The second opposing portion 4B includes another portion of each of the first wiring layer 41, the second wiring layer 42, the insulator layer 44, the first protective layer 46, and the second protective layer 47.

[0058] The first facing portion 4A has a first recess 4C (counterbore) formed therein to accommodate the first power semiconductor element 2A and the plurality of first conductive posts 3A. The first recess 4C is recessed relative to the lower surface of the first facing portion 4A that faces the first insulating substrate 1A in the first direction Z. The lower surface of the first facing portion 4A is bonded to the first surface 1A1 of the first insulating substrate 1A.

[0059] The first recess 4C has a bottom surface that faces the first surface 1A1 across the first power semiconductor element 2A in the first direction Z, and a wall surface that protrudes from the outer periphery of the bottom surface in the first direction Z and faces the side surfaces of the first power semiconductor element 2A and the plurality of first conductive posts 3A in each of the second direction Y and the third direction X. The lower end of the wall surface of the first recess 4C is connected to the inner periphery of the lower surface of the first facing portion 4A. The lower surface of the first facing portion 4A, the bottom surface of the first recess 4C, and the wall surface can each be a single flat surface or curved surface, or a concave-convex surface formed by connecting multiple flat surfaces or curved surfaces.

[0060] In the first opposing portion 4A, at least the first wiring layer 41 and the first protective layer 46 may be formed on the bottom surface of the first recess 4C. For example, no other wiring layer stacked on the first wiring layer 41 in the first direction Z, nor any insulating layer separating the other wiring layer from the first wiring layer 41, may be formed on the bottom surface of the first recess 4C.

[0061] On the bottom surface of the first recess 4C, for example, portions of the first wiring layer 41 and the first protective layer 46 are exposed. The first wiring layer 41 exposed on the bottom surface of the first recess 4C is bonded to the other ends of the plurality of first conductive posts 3A in the first direction Z via a bonding material such as solder. On the wall surface of the first recess 4C, for example, portions of the insulator layer 44 and the second wiring layer 42 are exposed.

[0062] On the lower surface of the first opposing portion 4A, for example, another portion of the insulating layer 44 and the second wiring layer 42 are exposed. The second wiring layer 42 exposed on the lower surface of the first opposing portion 4A is bonded to the conductive layer 11 of the first insulating substrate 1A via a bonding material such as solder. When viewed from above, the second wiring layer 42 exposed on the lower surface of the first opposing portion 4A is continuously arranged so as to surround the entire circumference of the first recess 4C. When viewed from above, the conductive layer 11 of the first insulating substrate 1A is continuously arranged so as to surround the entire circumference of the first power semiconductor element 2A. When viewed from above, the bonding material bonding the second wiring layer 42 and the conductive layer 11 is continuously arranged so as to surround the entire circumference of the first power semiconductor element 2A and the first recess 4C that accommodates the first power semiconductor element 2A. As a result, the interior of the first recess 4C is sealed by the first insulating substrate 1A and the bonding material.

[0063] The second facing portion 4B includes a second recessed portion 4D (counterbore) for accommodating the second power semiconductor element 2B and the plurality of second conductive posts 3B. The second recessed portion 4D is recessed relative to the lower surface of the second facing portion 4B that faces the second insulating substrate 1B in the first direction Z. The lower surface of the second facing portion 4B faces the second surface 1B1 of the second insulating substrate 1B without the second power semiconductor element 2B interposed therebetween. The second recessed portion 4D includes a bottom surface that faces the second surface 1B1 in the first direction Z, across the second power semiconductor element 2B, and a wall surface that protrudes from the outer periphery of the bottom surface in the first direction Z and faces the side surfaces of the second power semiconductor element 2B and the plurality of second conductive posts 3B in each of the second direction Y and the third direction X. The lower end of the wall surface of the second recessed portion 4D is connected to the inner periphery of the lower surface of the second facing portion 4B. Each of the lower surface of the second facing portion 4B, the bottom surface of the second recess 4D, and the wall surface may be a single flat surface or curved surface, or a concave-convex surface formed by connecting a plurality of flat surfaces or curved surfaces.

[0064] The second opposing portion 4B includes a first wiring layer 41, a second wiring layer 42, an insulator layer 44, a first protective layer 46, and a second protective layer 47. In the second opposing portion 4B, the first protective layer 46, the first wiring layer 41, the insulator layer 44, the second wiring layer 42, and the second protective layer 47 are stacked in the order described above in the first direction Z.

[0065] In the second opposing portion 4B, at least the first wiring layer 41 and the first protective layer 46 may be formed on the bottom surface of the second recess 4D. For example, no other wiring layer stacked on the first wiring layer 41 in the first direction Z, and no insulating layer separating the other wiring layer from the first wiring layer 41, may be formed on the bottom surface of the second recess 4D.

[0066] On the bottom surface of the second recess 4D, for example, a portion of each of the first wiring layer 41 and the first protective layer 46 is exposed. Each of the first wiring layers 41 exposed on the bottom surface of the second recess 4D is bonded to the other end of each of the plurality of second conductive posts 3B in the first direction Z via a bonding material such as solder. On the wall surface of the second recess 4D, for example, a portion of each of the insulator layer 44 and the second wiring layer 42 is exposed.

[0067] On the lower surface of the second opposing portion 4B, for example, another portion of the insulating layer 44 and the second wiring layer 42 are exposed. The second wiring layer 42 exposed on the lower surface of the second opposing portion 4B is bonded to the conductor layer 11 of the second insulating substrate 1B via a bonding material such as solder. When viewed from above, the second wiring layer 42 exposed on the lower surface of the second opposing portion 4B is continuously arranged so as to surround the entire circumference of the second recess 4D. When viewed from above, the conductor layer 11 of the second insulating substrate 1B is continuously arranged so as to surround the entire circumference of the second power semiconductor element 2B. When viewed from above, the bonding material bonding the second wiring layer 42 and the conductor layer 11 is continuously arranged so as to surround the second power semiconductor element 2B and the entire circumference of the second recess 4D that accommodates the second power semiconductor element 2B. As a result, the interior of the second recess 4D is sealed by the second insulating substrate 1B and the bonding material.

[0068] The interiors of the first recess 4C and the second recess 4D are filled with a gas such as air.

[0069] A portion of the first wiring layer 41 of the printed circuit board 4 is exposed from the first and second protective layers 46, 47, forming first external connection terminals 41A for connecting to external equipment in the power module 101. A portion of the first wiring layer 41 is exposed from the first and second protective layers 46, 47, forming second external connection terminals 41B and 41C for connecting to external equipment in the power module 101. Second external connection terminals 41A and 41B are control external terminals. A portion of the second wiring layer 42 of the printed circuit board 4 is exposed from the first and second protective layers 46, 47, forming third external connection terminals 42A and 42B for connecting to external equipment in the power module 101.

[0070] In this embodiment, solder is used as an example of the bonding material included in the power module 101, but the present invention is not limited thereto. Sintered silver, conductive adhesives, liquid bath diffusion bonding technology, etc. may also be used to bond the components included in the power module 101.

[0071] Next, the flow of major electrical signals within power module 101 will be described. First, the signal input to third external connection terminal 42A reaches the back electrode of first power semiconductor element 2A via second wiring layer 42 and conductive layer 11 of first insulating substrate 1A, and is output from main electrode 21A of first power semiconductor element 2A. The signal output from main electrode 21A of first power semiconductor element 2A reaches the back electrode of second power semiconductor element 2B via first conductor post 3A, first wiring layer 41, through-hole 45, and conductive layer 11 of second insulating substrate 1B, and is output from main electrode 21B of second power semiconductor element 2B. The signal output from main electrode 21B of second power semiconductor element 2B reaches first external connection terminal 41A via second conductor post 3B and first wiring layer 41, and is output to external equipment.

[0072] Furthermore, control signals are input from external devices to the control electrodes 22A and 22B of the first and second power semiconductor elements 2A and 2B respectively via the second external connection terminals 41B and 41C, the first wiring layer 41 , and the first and second conductor posts 3A and 3B.

[0073] <Power Module Manufacturing Method>

[0074] Below, refer to Figure 4 , an example of a method for manufacturing the power module 101 is described. Figure 4 As shown, first, a first semi-finished product 201, a second semi-finished product 202, and a printed circuit board 4 are prepared.

[0075] The first semi-finished product 201 is an integrated structure comprising a first insulating substrate 1A, a first power semiconductor element 2A, and a plurality of first conductive posts 3A. In the first semi-finished product 201, the first power semiconductor element 2A is bonded to the conductive layer 11 of the first insulating substrate 1A using solder or the like, and each of the plurality of first conductive posts 3A is bonded to the main electrode 21A or the control electrode 22A of the first power semiconductor element 2A using solder or the like.

[0076] The second semi-finished product 202 is an integrated product comprising a second insulating substrate 1B, a second power semiconductor element 2B, and a plurality of second conductive posts 3B. In the second semi-finished product 202, the second power semiconductor element 2B is bonded to the conductive layer 11 of the second insulating substrate 1B using solder or the like, and each of the plurality of second conductive posts 3B is bonded to the main electrode 21B or the control electrode 22B of the second power semiconductor element 2B using solder or the like.

[0077] The printed circuit board 4 includes a first facing portion 4A and a second facing portion 4B. The first facing portion 4A is a portion that is intended to be arranged so as to overlap with the first surface 1A1 of the first insulating substrate 1A in the first direction Z. The second facing portion 4B is a portion that is intended to overlap with the second surface 1B1 of the second insulating substrate 1B in the first direction Z.

[0078] A first recess 4C is formed in the first facing portion 4A. On the bottom surface of the first recess 4C, for example, portions of the first wiring layer 41 and the first protective layer 46 are exposed. On the wall surface of the first recess 4C, for example, portions of the insulator layer 44 and the third wiring layer are exposed. On the lower surface of the first facing portion 4A, for example, other portions of the insulator layer 44 and the third wiring layer are exposed. When viewed from above, the second wiring layer 42 exposed on the lower surface of the first facing portion 4A is continuously arranged so as to surround the entire circumference of the first recess 4C. When viewed from above, the conductor layer 11 of the first insulating substrate 1A is continuously arranged so as to surround the entire circumference of the first power semiconductor element 2A.

[0079] A second recess 4D is formed in the second opposing portion 4B. On the bottom surface of the second recess 4D, for example, portions of the first wiring layer 41 and the first protective layer 46 are exposed. On the wall surface of the second recess 4D, for example, portions of the insulator layer 44 and the third wiring layer are exposed. On the lower surface of the second opposing portion 4B, for example, other portions of the insulator layer 44 and the third wiring layer are exposed. When viewed from above, the second wiring layer 42 exposed on the lower surface of the second opposing portion 4B is continuously arranged so as to surround the entire circumference of the second recess 4D. When viewed from above, the conductor layer 11 of the second insulating substrate 1B is continuously arranged so as to surround the entire circumference of the second power semiconductor element 2B.

[0080] Second, a bonding material such as solder is continuously disposed on the conductive layer 11 so as to surround the entire circumference of the first power semiconductor element 2A. Furthermore, the bonding material such as solder is disposed on the main electrode 21A and the control electrode 22A of the first power semiconductor element 2A. Similarly, a bonding material such as solder is continuously disposed on the conductive layer 11 so as to surround the entire circumference of the second power semiconductor element 2B. The bonding material such as solder is disposed on the main electrode 21B and the control electrode 22B of the second power semiconductor element 2B.

[0081] No. 3, such as Figure 4As shown, the first opposing portion 4A is arranged so as to overlap with the first surface 1A1 of the first insulating substrate 1A in the first direction Z, and the second opposing portion 4B is arranged so as to overlap with the second surface 1B1 of the second insulating substrate 1B in the first direction Z. In this case, the first recess 4C is arranged so as to overlap with the first power semiconductor element 2A and the plurality of first conductive posts 3A in the first direction Z. Furthermore, the second recess 4D is arranged so as to overlap with the second power semiconductor element 2B and the plurality of second conductive posts 3B in the first direction Z.

[0082] Afterwards, if Figure 4 As shown by the arrows in , the first semi-finished product 201 and the second semi-finished product 202 move relative to the printed circuit board 4 in the first direction Z. Furthermore, each of the plurality of first conductor posts 3A is bonded to the first wiring layer 41 exposed on the bottom surface of the first recess 4C via the bonding material, and the conductor layer 11 of the first insulating substrate 1A is bonded to the second wiring layer 42 exposed on the bottom surface of the first opposing portion 4A via the bonding material. Furthermore, each of the plurality of second conductor posts 3B is bonded to the first wiring layer 41 exposed on the bottom surface of the second recess 4D via the bonding material, and the conductor layer 11 of the second insulating substrate 1B is bonded to the second wiring layer 42 exposed on the bottom surface of the second opposing portion 4B via the bonding material.

[0083] In this way, the first semi-finished product 201 and the second semi-finished product 202 are integrated with the printed circuit board 4. The first recess 4C is sealed by the first insulating substrate 1A and the aforementioned bonding material. The second recess 4D is sealed by the second insulating substrate 1B and the aforementioned bonding material. The first power semiconductor element 2A and the plurality of first conductive posts 3A are housed in the first recess 4C. The second power semiconductor element 2B and the plurality of second conductive posts 3B are housed in the second recess 4D.

[0084] <Effects of Power Modules>

[0085] The effects of the power module 101 will be described in comparison with a power module according to a comparative example.

[0086] Figure 20 as well as Figure 21The power module 300 according to Comparative Example 1 shown includes multiple insulating substrates 301, multiple power semiconductor elements 302, multiple bonding wires 303, and multiple lead frames 304. Each bonding wire 303 electrically connects the power semiconductor element 302 to the conductive layer of the insulating substrate 301, or between the power semiconductor element 302 and the lead frame 304. The multiple lead frames 304 are generally manufactured by punching out a metal plate made of copper or iron. Therefore, the inner leads 304A that form the bonding areas with the bonding wires 303 in each of the multiple lead frames 304 are arranged on the same plane. In such a power module 300 having a plurality of lead frames 304, each lead frame 304 is arranged so as not to overlap with the power semiconductor element 302 when viewed from above. Furthermore, in each of the plurality of lead frames 304, the portion 304B constituting the external connection terminal is arranged further outward than the inner lead 304A when viewed from above. Therefore, it is difficult to reduce the area of the power module 300 when viewed from above.

[0087] Furthermore, in power module 300 , the electrical path between the power semiconductor element and the external connection terminal is long due to the bonding wires 303 and lead frame 304 connected in series. Therefore, it is difficult to reduce the wiring inductance L of power module 300 .

[0088] Figure 22 as well as Figure 23 The power module 310 according to the comparative example 2 shown in FIG. Figure 24 as well as Figure 25 The power module 320 according to Comparative Example 3 shown in FIG. Figure 26 as well as Figure 27 Each power module 330 according to Comparative Example 4 includes an insulating substrate 311 , a first power semiconductor element 312A, a second power semiconductor element 312B, a conductive post 313 , and a printed circuit board 314 , similar to the power module 101 . However, it differs from the power module 101 in that no recess is formed in the printed circuit board 314 .

[0089] In power module 310, wiring layers 315 on printed circuit board 314 constitute external connection terminals. The electrical path between each power semiconductor element and wiring layer 315 includes conductor posts 313 instead of bonding wires and inner leads. Conductor posts 313 electrically connect the first power semiconductor element 312A or the second power semiconductor element 312B, which are arranged so as to overlap each other when viewed from above, to the wiring layer on printed circuit board 314. Therefore, in power module 310, the length of conductor posts 313 can be made shorter than the combined length of the bonding wires and inner leads, allowing wiring inductance L to be lower than that of power module 300.

[0090] On the other hand, in the power module 310, the entire printed circuit board 314 is disposed on the power semiconductor element 312. Therefore, it is difficult to reduce the size of the power module 310 in the first direction Z, and in some cases, the size of the power module 310 in the first direction Z becomes larger than the size of the power module 300.

[0091] Furthermore, power module 310 requires a conductor block 317 for electrically connecting the opposing insulating substrate 311 and the wiring layer 315 of the printed circuit board 314 without intervening through the power semiconductor element 312. The length of conductor block 317 in the first direction Z is longer than the length of conductor post 313 in the first direction Z by an amount corresponding to the thickness of the power semiconductor element. Consequently, it is difficult to reduce the manufacturing cost of power module 310.

[0092] Furthermore, in power module 310 , printed circuit board 314 includes conductor vias 318 for electrically connecting wiring layers 315 and 316 stacked in first direction Z. Therefore, power module 310 including both conductor blocks 317 and conductor vias 318 has high manufacturing costs.

[0093] Furthermore, in a plan view, external connection terminals 315A, corresponding to third external connection terminals 42A of power module 101, and external connection terminals 316A, corresponding to first external connection terminals 41A of power module 101, are arranged on one end side of power module 310 in the second direction Y. In power module 310, external connection terminals 315A, conductive blocks 317, the first conductive layer of insulating substrate 314, power semiconductor element 312A, wiring layer 315, conductive blocks 317, the second conductive layer of insulating layer 314, power semiconductor element 312B, conductive vias 318, wiring layer 316, and external connection terminals 316A are electrically connected in this order.

[0094] Figure 24 as well as Figure 25 Power module 320 according to Comparative Example 3 shown differs from power module 310 in that printed circuit board 314 does not include conductor through-hole 318. In such power module 320, only a portion of the current path formed inside power module 310 is formed; the remaining portion of the current path must be formed outside power module 320. Figure 24Arrow C in FIG2 schematically represents the current path within power module 320. In power module 320, external connection terminal 315C, which forms the remainder of the current path and is used for connection to external wiring, is located on the side opposite to external connection terminal 315A, which corresponds to third external connection terminal 42A of power module 101. In power module 310, external connection terminal 315A, conductor block 317, the first conductor layer of insulating substrate 314, power semiconductor element 312A, wiring layer 315, conductor block 317, the second conductor layer of insulating layer 314, power semiconductor element 312B, wiring layer 315, and external connection terminal 315C are electrically connected in this order. Therefore, the combined length of the current path within power module 320 and the external wiring is longer than the length of the current path electrically connecting external connection terminal 315A and external connection terminal 316A in power module 310.

[0095] Figure 26 as well as Figure 27 Power module 330 according to Comparative Example 4 shown differs from power module 310 in that printed circuit board 314 does not include conductor through-hole 318. Furthermore, power module 330 differs from power module 320 in that a current path equivalent to that formed within power module 310 is formed within the printed circuit board 314. Figure 26 as well as Figure 27 Arrows C schematically represent the current path within power module 330. In power module 330, external connection terminals 315A, conductor blocks 317, the first conductor layer of insulating substrate 314, power semiconductor element 312A, wiring layer 315D, conductor blocks 317, the second conductor layer of insulating layer 314, power semiconductor element 312B, wiring layer 315E, and external connection terminals 315F are electrically connected in this order.

[0096] In the power module 330, it is difficult to reduce the size of the first power semiconductor element 312A and the second power semiconductor element 312B in the direction in which the first power semiconductor element 312A and the second power semiconductor element 312B are arranged side by side (in the direction in which the first power semiconductor element 312A and the second power semiconductor element 312B are arranged side by side). Figure 26 The dimension W1 of the wiring layer 315D in the third direction X (in the third direction X) that constitutes a portion of the current path between the first power semiconductor element 312A and the second power semiconductor element 312B is shown. Furthermore, in the power module 330, the wiring layer 315D and the wiring layer 315E are arranged side by side between the control terminal 315G connected to the first power semiconductor element 312A and the control terminal 315G connected to the second power semiconductor element 312B. Therefore, in order to increase the dimension W2 of the wiring layer 315D in the third direction X to minimize wiring inductance, the dimension of the power module 330 in the third direction X must be increased.

[0097] In contrast, the power module 101 includes the first conductive post 3A and the second conductive post 3B instead of the bonding wire 303 and the lead frame 304 . Therefore, the wiring inductance L of the power module 101 can be lower than the wiring inductance L of the power module 300 .

[0098] Furthermore, in power module 101, no other wiring layer stacked on first wiring layer 41 in the first direction Z, nor any insulating layer separating such wiring layer from first wiring layer 41, is formed on the bottom surface of first recess 4C. Therefore, in power module 101, the thickness of a portion of first opposing portion 4A, which is arranged to overlap first power semiconductor element 2A in the first direction Z, is thinner than the thickness of printed circuit board 314, which is arranged to overlap power semiconductor elements 312A and 312B in power modules 310 to 330.

[0099] Therefore, the power module 101 achieves both reduced wiring inductance associated with high-speed switching and miniaturization compared to the power module 300 , and also achieves both reduced wiring inductance associated with high-speed switching and thinning compared to the power modules 310 to 330 .

[0100] Furthermore, in power module 101, first recess 4C and second recess 4D are formed in printed circuit board 4. Therefore, conductor block 317, which is required in power modules 310 to 330 that do not have first recess 4C and second recess 4D, is no longer required. Consequently, the manufacturing cost of power module 101 can be reduced compared to power modules 310 to 330.

[0101] <Modification>

[0102] Figure 5 The power module 101 shown has Figures 1 to 3 The power module 101 shown has basically the same structure as Figures 1 to 3 The power module 101 shown is different in that it includes a printed circuit board 4 that does not include a through hole 45 and a conductor block 48 instead of the printed circuit board 4 that includes a through hole 45. Figure 5 In FIG. 4 , the conductor block 48 is shown only in the second recess 4D, but the conductor block 48 may be arranged inside at least one of the first recess 4C and the second recess 4D.

[0103] like Figure 6 As shown, in Figure 5 In the manufacturing method of the power module 101 shown, a second semi-finished product 202 including a conductor block 48 is prepared, and the conductor block 48 is bonded to the first wiring layer 41 of the printed circuit board 4 with a bonding material such as solder.

[0104] The manufacturing cost of the printed circuit board 4 including the through-hole 45 tends to be higher than the total manufacturing cost of the printed circuit board 4 not including the through-hole 45 and the manufacturing cost of the conductor block 48. Specifically, when the through-hole 45 is formed as a columnar metal body pressed into the through-hole of the printed circuit board 4 in a manner capable of withstanding a large current, the manufacturing cost of the printed circuit board 4 including the through-hole 45 tends to be much higher than that of the printed circuit board not including the through-hole 45, and further tends to be higher than the total manufacturing cost of the printed circuit board not including the conductor through-hole and the conductor block. Therefore, in Figure 5 In the power module 101 shown, Figures 1 to 3 Compared with the power module 101 shown in FIG. 1 , the manufacturing cost can be reduced.

[0105] In addition, Figure 5 The power module 101 shown is also Figures 1 to 3 The illustrated power module 101 similarly achieves both reduced wiring inductance associated with high-speed switching and miniaturization compared to the power module 300 , and also achieves both reduced wiring inductance associated with high-speed switching and thinning compared to the power modules 310 to 330 .

[0106] Implementation method 2.

[0107] like Figures 7 to 9 As shown, power module 102 according to Embodiment 2 has a substantially similar structure to power module 101 according to Embodiment 1. However, it differs from power module 101 in that second surface 1B1 of second insulating substrate 1B faces the side of first insulating substrate 1A opposite to first surface 1A1. The following mainly describes the differences between power module 102 and power module 101.

[0108] The first recess 4C faces the first surface 1A1. The second recess 4D faces the second surface 1B1. The first protective layer 46 of the printed circuit board 4 is not included in the second facing portion 4B facing the second insulating substrate 1B. The first protective layer 46 is arranged side by side with the second insulating substrate 1B in the second direction Y and the third direction X. The second protective layer 47 is not included in the first facing portion 4A facing the first insulating substrate 1A. The second protective layer 47 is arranged side by side with the first insulating substrate 1A in the second direction Y and the third direction X.

[0109] Conductive layer 11 of second insulating substrate 1B is bonded to first wiring layer 41 via a bonding material such as solder. Main electrode 21B and control electrode 22B of second power semiconductor element 2B are electrically connected to respective patterns of second wiring layer 42 via second conductive posts 3B. A portion of second wiring layer 42 constitutes external connection terminal 42C. Another portion of second wiring layer 42 constitutes external connection terminal 42D, which serves as an external control terminal.

[0110] Each of the first wiring layers 41 is not electrically connected to the second wiring layer 42. In other words, the printed circuit board 4 does not include the through-hole 45 for electrically connecting at least any one of the first wiring layers 41 and the second wiring layer 42.

[0111] In power module 102, first wiring layer 41 and second wiring layer 42 are electrically connected only via first power semiconductor element 2A or second power semiconductor element 2B. Main electrode 21B of second power semiconductor element 2B is electrically connected to second wiring layer 42 via second conductive post 3B.

[0112] like Figure 9 As shown, the power module 102 has, for example, two-fold rotational symmetry about the center of a cross section perpendicular to the third direction X. In this case, the center of the power module 102 is disposed within the insulating layer 44 of the printed circuit board 4 .

[0113] Next, the flow of major electrical signals within power module 102 will be described. First, the signal input to third external connection terminal 42A reaches the back electrode of first power semiconductor element 2A via second wiring layer 42 and conductive layer 11 of first insulating substrate 1A, and is output from main electrode 21A of first power semiconductor element 2A. The signal output from main electrode 21A of first power semiconductor element 2A reaches the back electrode of second power semiconductor element 2B via first conductor post 3A, first wiring layer 41, and conductive layer 11 of second insulating substrate 1B, and is output from main electrode 21B of second power semiconductor element 2B. The signal output from main electrode 21B of second power semiconductor element 2B reaches external connection terminal 42C via second conductor post 3B and second wiring layer 42, and is output to external equipment.

[0114] The manufacturing method of the power module 102 has basically the same structure as the manufacturing method of the power module 101, but Figure 10 As shown, the manufacturing method of power module 102 differs from the manufacturing method of power module 101 in that the first semi-finished product 201 and the second semi-finished product 202 are arranged in opposite directions relative to the printed circuit board 4. On the other hand, the manufacturing method of power module 102 is similar to the manufacturing method of power module 101 in that the first opposing portion 4A is arranged so as to overlap with the first surface 1A1 of the first insulating substrate 1A in the first direction Z, and the second opposing portion 4B is arranged so as to overlap with the second surface 1B1 of the second insulating substrate 1B in the first direction Z.

[0115] Power module 102 can achieve the same effects as power module 101. Furthermore, the manufacturing cost of power module 102, which includes a printed circuit board 4 without through-holes 45, can be reduced compared to the manufacturing cost of power module 101, which includes a printed circuit board 4 with through-holes 45. In other words, the manufacturing cost of power module 102 can be significantly reduced compared to power modules 310 to 330.

[0116] Implementation method 3.

[0117] like Figure 11 As shown, power module 103 according to Embodiment 3 has basically the same structure as power module 102 according to Embodiment 2, but differs from power module 102 in that first power semiconductor element 2A is embedded in resin 6. The following mainly describes the differences between power module 103 and power module 102.

[0118] The second power semiconductor element 2B may be embedded in a resin 6 different from the resin 6 in which the first power semiconductor element 2A is embedded.

[0119] The first conductor post 3A has an exposed portion 31A that protrudes from the resin 6 formed to cover the first power semiconductor element 2A. The second conductor post 3B has an exposed portion 31B that protrudes from the resin 6 formed to cover the second power semiconductor element 2B. Exposed portions 31A and 31B include, for example, the upper surfaces of the first and second conductor posts 3A and 3B, respectively. Exposed portion 31A is electrically connected to the first wiring layer 41 of the first opposing portion 4A via a bonding material (not shown). Exposed portion 31B is electrically connected to the second wiring layer 42 of the second opposing portion 4B via a bonding material (not shown). The bonding material (not shown) is not embedded in the resin 6.

[0120] In the power module 103 , at least one of the first power semiconductor element 2A and the second power semiconductor element 2B may be embedded in the resin 6 , while the entire first conductive post 3A and the entire second conductive post 3B may be exposed from the resin 6 .

[0121] The material constituting the resin 6 may be any electrically insulating resin material. The resin 6 formed to cover the first power semiconductor element 2A, for example, does not contact the first wiring layer 41 of the first opposing portion 4A. The resin 6 formed to cover the second power semiconductor element 2B, for example, does not contact the second wiring layer 42 of the second opposing portion 4B.

[0122] The method for manufacturing the power module 103 has basically the same structure as the method for manufacturing the power module 102, but differs in that a plurality of semi-finished products 201 and 202 are prepared instead of the semi-finished products 201 and 202. Figure 12The semi-finished product 203 is shown. In the semi-finished product 203, the resin 6 is formed so as to embed the entire first power semiconductor element 2A or the second power semiconductor element 2B and the other parts except the exposed portions 31A, 31B of the first conductor post 3A or the second conductor post 3B.

[0123] The semi-finished product 203 may include a plurality of first power semiconductor elements 2A or a plurality of second power semiconductor elements 2B.

[0124] Preferably, before assembling a power module 103 comprising a plurality of semi-finished products 203, a process is performed to inspect the characteristics of the power semiconductor elements embedded in the resin 6 for each semi-finished product 203. Only semi-finished products 203 judged as good in this process are used to assemble the power module 103. This prevents a power module 103 from being judged as defective simply because the characteristics of the power semiconductor elements in a portion of the plurality of semi-finished products 203 are poor. Any inspection can be performed during the inspection process, such as a withstand voltage test. During the withstand voltage test on the semi-finished products 203, a high voltage is applied to the power semiconductor elements embedded in the resin 6, preventing discharge in the air and enabling appropriate inspection.

[0125] According to power module 103, first power semiconductor element 2A and second power semiconductor element 2B are each embedded in resin 6. Therefore, first power semiconductor element 2A and second power semiconductor element 2B are less susceptible to external environmental influences (humidity, contamination), thereby providing high reliability for power module 103.

[0126] Furthermore, the power module 103 can be manufactured to include only the semi-finished products 203 that have been inspected and confirmed to be good. Therefore, in the power module 103, both reliability and production efficiency can be improved.

[0127] The semiconductor material of each of the first power semiconductor element 2A and the second power semiconductor element 2B of the power module 103 is not particularly limited and may be silicon carbide (SiC). While SiC is more expensive than silicon (Si), as described above, the production efficiency of the power module 103 is high, thereby suppressing increases in manufacturing costs caused by the rejection of other good power semiconductor elements embedded in the power module 103 due to defective power semiconductor elements.

[0128] The power module 103 may have the same structure as the power module 101 according to the first embodiment, except that the first power semiconductor element 2A is embedded in the resin 6 .

[0129] Implementation method 4.

[0130] like Figure 13As shown, power module 104 according to Embodiment 4 has a structure substantially similar to power module 102 according to Embodiment 2. However, it differs from power module 102 in that a first conductive plate 1E is included as the first substrate instead of the first insulating substrate. The following mainly describes the differences between power module 104 and power module 102.

[0131] The first conductor plate 1E is made of, for example, a metal material with high thermal conductivity. The first conductor 1E is, for example, a metal plate that functions as a heat sink. The first conductor plate 1E has a first surface 1E1 that faces the first facing portion 4A. The first power semiconductor element 2A is mounted on the first surface 1E1.

[0132] The power module 104 further includes, for example, a second conductive plate 1F serving as a second substrate. The second conductive plate 1F can be made of any metal material, for example, a metal material with high thermal conductivity. The second conductive plate 1F functions as a heat sink. The second conductive plate 1F has a second surface 1F1 facing the second facing portion 4B. The second power semiconductor element 2B is mounted on the second surface 1F1.

[0133] The thickness of the first conductor plate 1E is, for example, equal to the thickness of the first wiring layer 41 that faces the first power semiconductor element 2A. The thickness of the second conductor plate 1F is, for example, equal to the thickness of the second wiring layer 42 that faces the second power semiconductor element 2B. This reduces warping of the power module 104. Furthermore, since the first conductor plate 1E and the second conductor plate 1F are each a single metal plate, their respective thicknesses can be easily adjusted.

[0134] The power module 104 includes the first conductive plate 1E, which is less expensive than the first insulating substrate 1A. Therefore, the manufacturing cost of the power module 104 is lower than that of the power modules 101 to 103 .

[0135] The power module 104 may include a second insulating substrate 1B as the second substrate. The power module 104 may also have the same structure as the power module 101 according to the first embodiment, except that the first conductive plate 1E is included as the first substrate instead of the first insulating substrate.

[0136] <Modification>

[0137] like Figure 14As shown, the first conductor plate 1E may also include a thick-walled portion 13 and a thin-walled portion 14. The thick-walled portion 13 protrudes further toward the printed circuit board 4 side than the thin-walled portion 14 in the first direction Z. The first surface 1E1, as the top surface of the thick-walled portion 13, is arranged at a position closest to the first opposing portion 4A on the surface of the first conductor plate 1E. The thin-walled portion 14 is arranged so as to surround the entire periphery of the thick-walled portion 13 when viewed from above. The thick-walled portion 13 is arranged inside the first recess 4C. Preferably, the thick-walled portion 13 is formed in a manner that is interlocked with the first recess 4C. The second conductor plate 1F may also include a thick-walled portion and a thin-walled portion in the same manner. In Figure 14 In the power module 104 shown, Figure 13 Compared with the power module 103 shown, the first recess 4C of the printed circuit board 4 and the first conductor plate 1E are more easily aligned.

[0138] Implementation method 5.

[0139] like Figure 15 As shown, power module 105 according to the fifth embodiment has basically the same structure as power module 102 according to the second embodiment. However, it differs from power module 105 in that first power semiconductor element 2A, multiple first conductive posts 3A, and the portion of first opposing portion 4A connected to first conductive posts 3A are embedded in resin 7. The following mainly describes the differences between power module 105 and power module 102.

[0140] In the power module 105 , the first power semiconductor element 2A, the plurality of first conductive posts 3A, portions of the first opposing portion 4A connected to the first conductive posts 3A via a bonding material (not shown), and the bonding material are embedded in the resin 7 .

[0141] The second power semiconductor element 2B, the plurality of second conductor posts 3B, the portion of the second opposing portion 4B connected to the second conductor posts 3B via a bonding material (not shown), and the bonding material may be embedded in a resin 7 different from the resin 7 in which the first power semiconductor element 2A is embedded.

[0142] The material constituting the resin 7 may be any resin material having electrical insulation properties, and may be, for example, an underfill resin.

[0143] In the method for manufacturing power module 105, first, a first power semiconductor element 2A having a plurality of first conductive posts 3A bonded to main electrodes 21A and control electrodes 22A, a second power semiconductor element 2B having a plurality of second conductive posts 3B bonded to main electrodes 21B and control electrodes 22B, and a printed circuit board 4 are prepared. The first power semiconductor element 2A and the second power semiconductor element 2B are not mounted on the first insulating substrate 1A or the second insulating substrate 1B.

[0144] Second, the first wiring layer 41 of the printed circuit board 4 and each of the plurality of first conductor posts 3A are bonded together with a bonding material (not shown), and the second wiring layer 42 and each of the plurality of first conductor posts 3A are bonded together with a bonding material (not shown).

[0145] Third, resin 7 is formed to cover the first power semiconductor element 2A, the plurality of first conductor posts 3A, and the portion of the first opposing portion 4A connected to the first conductor posts 3A via a bonding material (not shown), which has been integrated in the previous step, as well as the bonding material. Similarly, resin 7 is formed to cover the second power semiconductor element 2B, the plurality of second conductor posts 3B, and the portion of the second opposing portion 4B connected to the second conductor posts 3B via a bonding material (not shown), as well as the bonding material. Resin 7 is formed to expose the back electrodes of each of the first power semiconductor element 2A and the second power semiconductor element 2B.

[0146] Fourthly, the back electrode of the first power semiconductor element 2A exposed from the resin 7 is bonded to the conductive layer 11 of the first insulating substrate 1A via the bonding material 5 , and the back electrode of the second power semiconductor element 2B exposed from the resin 7 is bonded to the second insulating substrate 1B via the bonding material 5 .

[0147] In this way, the power module 105 is manufactured.

[0148] In power module 105, first power semiconductor element 2A and second power semiconductor element 2B are each embedded in resin 6. Therefore, first power semiconductor element 2A and second power semiconductor element 2B are less susceptible to external environmental influences (humidity, contamination), thereby providing high reliability for power module 105.

[0149] In addition, the power module 105 may also have a structure similar to any of the power modules 101, 103, and 104 involved in embodiments 1, 3, and 4, except that the first power semiconductor element 2A, the multiple first conductor posts 3A, and the portion connected to the first conductor posts 3A in the first opposing portion 4A are embedded in the resin 7.

[0150] Implementation method 6.

[0151] like Figure 16 As shown, power module 106 according to the sixth embodiment has a structure basically similar to power module 102 according to the second embodiment. However, it differs from power module 102 in that the space between first insulating substrate 1A and first opposing portion 4A facing first power semiconductor element 2A and first conductive post 3A is filled with resin 8. The following mainly describes the differences between power module 106 and power module 102.

[0152] In the first recess 4C, the resin 8 fills the space formed around the first insulating substrate 1A, the first power semiconductor element 2A, the plurality of first conductive posts 3A, and the bonding material.

[0153] In the second recess 4D, the space formed around the second insulating substrate 1B, the second power semiconductor element 2B, the plurality of second conductive posts 3B, and the bonding material may also be filled with the resin 8 .

[0154] The material constituting the resin 8 is, for example, an underfill resin and has, for example, thermosetting properties or ultraviolet curing properties.

[0155] A first through hole 50A connected to the interior of the first recess 4C is formed in the first facing portion 4A. For example, the first through hole 50A is formed to penetrate the first wiring layer 41 and the first protective layer 46 facing the bottom surface of the first recess 4C.

[0156] A second through hole 50B is formed in the second facing portion 4B and communicates with the interior of the second recess 4D. For example, the second through hole 50B is formed to penetrate the second wiring layer 42 and the second protective layer 47 facing the bottom surface of the second recess 4D.

[0157] The first through-hole 50A and the second through-hole 50B are formed as passages for introducing the resin 8 into the first recess 4C or the second recess 4D.

[0158] In the method for manufacturing power module 106, a printed circuit board 4 having first through-holes 50A and second through-holes 50B formed therein is prepared. Subsequently, similar to the method for manufacturing power module 102, after printed circuit board 4, first semi-finished product 201, and second semi-finished product 202 are assembled, a liquid curable resin material is introduced into first recess 4C and second recess 4D through first through-holes 50A and second through-holes 50B, respectively. The liquid curable resin material then cures to form resin 8, thereby manufacturing power module 106.

[0159] In power module 106, similar to power module 105, first power semiconductor element 2A and second power semiconductor element 2B are each embedded in resin 6. Therefore, first power semiconductor element 2A and second power semiconductor element 2B are less susceptible to the external environment (humidity, contamination), thereby providing high reliability for power module 106.

[0160] Furthermore, power module 106 includes first through-hole 50A and second through-hole 50B for introducing the material constituting resin 8 into first recess 4C and second recess 4D. Therefore, resin 8 can be formed after assembling printed circuit board 4, first semi-finished product 201, and second semi-finished product 202 in the same process as the manufacturing method of power module 102. Therefore, power module 106 can be manufactured more easily than power module 105.

[0161] Furthermore, in power module 106, bonding material 5 bonding first insulating substrate 1A and first power semiconductor element 2A is covered with resin 8. Therefore, even when power module 106 is exposed to a temperature cycle environment, bonding material 5 is prevented from breaking. Consequently, power module 106 has high reliability.

[0162] <Modification>

[0163] like Figure 17 As shown, in the power module 106, within the first recess 4C, at least the first power semiconductor element 2A, the bonding material 5 bonding the first power semiconductor element 2A and the first insulating substrate 1A, the plurality of first conductor posts 3A, and the bonding material bonding the plurality of first conductor posts 3A and the first opposing portion 4A are embedded in the resin 8.

[0164] The power module 106 may also have the same structure as any of the power modules 101, 103, and 104 involved in embodiments 1, 3, and 4, except that the space between the first insulating substrate 1A facing the first power semiconductor element 2A and the first conductive post 3A and the first opposing portion 4A is filled with resin 8.

[0165] Implementation method 7.

[0166] like Figure 18 As shown, power module 107 according to Embodiment 7 has a configuration substantially similar to power module 102 according to Embodiment 2, but differs from power module 106 in that printed circuit board 4 is a ceramic substrate. The following mainly describes the differences between power module 107 and power module 102.

[0167] The printed circuit board 4 is a ceramic substrate comprising a base material 49A made of ceramic, and a first wiring layer 41 and a second wiring layer 42 (conductive layers) laminated on the base material 49A. The first wiring layer 41 is disposed on one surface of the base material 49A. The second wiring layer 42 is disposed on the other surface of the base material 49A. The printed circuit board 4 may further include a base material 49B and a base material 49C, for example, so as to sandwich the base material 49A, the first wiring layer 41, and the second wiring layer 42 from the first direction Z.

[0168] The material constituting the base materials 49A, 49B, and 49C includes, for example, at least one selected from the group consisting of aluminum oxide (Al2O3), aluminum nitride (AlN), and silicon nitride (Si3N4). Such ceramic materials have higher thermal conductivity than the resin material constituting the insulating layer 44.

[0169] The first recess 4C is formed by a through-hole formed in the base material 49A and the base material 49B blocking the through-hole. The second recess 4D is formed by a through-hole formed in the base material 49A and the base material 49C blocking the through-hole.

[0170] The thermal conductivity of the printed circuit board 4 of power module 107 is higher than that of the printed circuit board 4 of power module 102. Therefore, heat generated in the first power semiconductor element 2A is easily dissipated to the outside through the printed circuit board 4. As a result, the reliability of power module 107 is high. Furthermore, the vibration and impact resistance of the printed circuit board 4 of power module 107 is higher than that of the printed circuit board 4 of power module 102. Therefore, the reliability of power module 107 is also high in harsh environments requiring high vibration and impact resistance. The application range of power module 107 is wider than that of power module 102.

[0171] The power module 107 may have the same structure as the power module 101 according to the first embodiment or any of the power modules 103 to 106 according to the third to sixth embodiments, except that the printed circuit board 4 is a ceramic substrate.

[0172] Implementation method 8.

[0173] Figure 19 Power module 108 according to the seventh embodiment shown has a configuration substantially similar to power module 106 according to the sixth embodiment, but differs from power module 106 in that it further includes a cooler 9A connected to first insulating substrate 1A and a cooler 9B connected to first opposing portion 4A. The following mainly describes the differences between power module 108 and power module 106.

[0174] The first insulating substrate 1A further includes a third surface 1A2 located opposite to the first surface 1A1. The first facing portion 4A further includes a fourth surface 4A2 located opposite to the surface having the first recess 4C. The fourth surface 4A2 is the surface of the first protective layer 46.

[0175] The second insulating substrate 1B further includes a fifth surface 1B2 located opposite to the second surface 1B1. The second facing portion 4B further includes a sixth surface 4B2 located opposite to the surface having the second recess 4D. The sixth surface 4B2 is the surface of the second protective layer 47.

[0176] The fifth surface 1B2 is, for example, arranged on the same plane as the fourth surface 4A2. The sixth surface 4B2 is, for example, arranged on the same plane as the third surface 1A2.

[0177] The cooler 9A is connected to, for example, the third surface 1A2 of the first insulating substrate 1A and the sixth surface 4B2 of the second opposing portion 4B. The cooler 9A is bonded to the third surface 1A2 and the sixth surface 4B2 via a bonding material 90, for example.

[0178] The cooler 9B is connected to, for example, the fifth surface 1B2 of the second insulating substrate 1B and the fourth surface 4A2 of the first opposing portion 4A. The cooler 9B is bonded to the fifth surface 1B2 and the fourth surface 4A2 via a bonding material 90, for example.

[0179] Each of the coolers 9A and 9B may have any structure as long as it can dissipate heat generated in the first power semiconductor element 2A and the second power semiconductor element 2B to the outside, and may be, for example, a heat sink including a base portion 91 and a plurality of fins 92 connected to the base portion 91. The coolers 9A and 9B may be made of any material with high thermal conductivity, such as copper (Cu) or aluminum (Al).

[0180] The material constituting the bonding material 90 may be any bonding material having a higher thermal conductivity than the material constituting the insulator layer 44 of the printed circuit board 4. When the power module 108 includes a first insulating substrate 1A and a second insulating substrate 1B as the first and second substrates, the material constituting the bonding material 90 may also be a conductive adhesive. Even in this case, the base material 10 of the first insulating substrate 1A, which is made of an electrically insulating material, is interposed between the first power semiconductor element 2A and the cooler 9A, thereby electrically insulating the first power semiconductor element 2A from the cooler 9A.

[0181] Furthermore, power module 108 only needs to include at least one of cooler 9A and cooler 9B. Furthermore, in power module 108 including cooler 9A and cooler 9B, cooler 9A only needs to be connected to at least a portion of first insulating substrate 1A, and cooler 9B only needs to be connected to at least a portion of second insulating substrate 1B.

[0182] Alternatively, power module 108 may have the same structure as any of power modules 101 to 105 according to Embodiments 1 to 5 or power module 107 according to Embodiment 7, except that it includes at least one of cooler 9A and cooler 9B. When power module 107 includes first conductor plate 1E as a first substrate, similar to power module 104, the material constituting bonding material 90 may be selected from materials having electrical insulation properties and higher thermal conductivity than the material constituting insulating layer 44 of printed circuit board 4.

[0183] As described above, the embodiments of the present disclosure are described, but the above embodiments can be modified in various ways. In addition, the scope of the present disclosure is not limited to the above embodiments. The scope of the present disclosure is indicated by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims.

[0184] (Explanation of Symbols)

[0185] 1A: First insulating substrate; 1A1, 1E1: First surface; 1A2: Third surface; 1B: Second insulating substrate; 1B1, 1F1: Second surface; 1B2: Fifth surface; 1E: First conductor plate; 1F: Second conductor plate; 2A: First power semiconductor element; 2B: Second power semiconductor element; 3A: First conductor post; 3B: Second conductor post; 4: Printed circuit board; 4A: First facing portion; 4A2: Fourth surface; 4B: Second facing portion; 4B2: Sixth surface; 4C: First recess; 4D: Second recess; 5, 90: Bonding material; 6, 7, 8: Resin; 9A, 9B: Cooler; 10, 49A, 49B, 49C: Base material; 11: First conductor layer; 12: Second conductor layer; 13: Thick-walled portion; 14: Thin-walled portion; 21A, 21B: Main electrodes; 22A, 22B: Control electrodes; 31A, 31B: Exposed portion; 41: First wiring layer; 42: Second wiring layer; 41A, 41B, 41C, 42A, 42B, 42C, 42D: Second external connection terminal; 44: Insulator layer; 45: Through hole; 46: First protective layer; 47: Second protective layer; 48: Conductor block; 50A: First through hole; 50B: Second through hole; 91: Base portion; 92: Wing; 101, 102, 103, 104, 105, 106, 107, 108, 300, 310, 320, 330: Power module; 201, 202, 203: Semi-finished product.

Claims

1. A power module comprising: a first substrate having a first surface; a first power semiconductor element mounted on the first surface; a printed circuit board having a first facing portion arranged to overlap the first surface of the first substrate in a first direction perpendicular to the first surface; as well as a first conductive post electrically connecting the first power semiconductor element and the first opposing portion; A first recessed portion is formed in the first facing portion, the recessed portion housing the first power semiconductor element and the first conductive post.

2. The power module according to claim 1, wherein: have: a second substrate having a second surface; and A second power semiconductor element is mounted on the second surface. The printed circuit board further includes a second facing portion arranged to overlap with the second surface of the second substrate in the first direction. The power module further includes a second conductive post electrically connecting the second power semiconductor element and the second opposing portion. A second recessed portion is formed in the second facing portion, and houses the second power semiconductor element and the second conductive post therein.

3. The power module according to claim 2, wherein: The second surface faces the side opposite to the first surface, The first recess faces the first surface. The second recessed portion faces the second surface and is arranged side by side with the first recessed portion in a direction along the first surface.

4. The power module according to claim 2, wherein: The second surface faces the same side as the first surface, The first recess faces the first surface. The second recessed portion faces the second surface and is arranged side by side with the first recessed portion in a direction along the first surface.

5. The power module according to any one of claims 1 to 4, wherein: The first substrate is an insulating substrate including a conductor layer having the first surface and an insulating layer stacked on the conductor layer in the first direction.

6. The power module according to any one of claims 1 to 5, wherein: The first substrate is a conductive plate having the first surface and a rear surface located on the opposite side to the first surface.

7. The power module according to claim 6, wherein: The first substrate includes a thin-walled portion facing the first facing portion of the printed circuit board without sandwiching the first power semiconductor element therebetween, and a thick-walled portion protruding in the first direction relative to the thin-walled portion. The first surface is a surface of the thick portion.

8. The power module according to any one of claims 1 to 7, wherein: The first power semiconductor element is embedded in the resin. The first conductive post has an exposed portion exposed from the resin. The exposed portion is electrically connected to the first opposing portion.

9. The power module according to any one of claims 1 to 7, wherein: The first power semiconductor element, the first conductive post, and a portion of the first opposing portion connected to the first conductive post are embedded in resin.

10. The power module according to claim 9, wherein: A space between the first substrate facing the first power semiconductor element and the first conductive post and the first opposing portion is filled with the resin.

11. The power module according to any one of claims 1 to 10, wherein: The printed circuit board is a ceramic substrate including a base material made of ceramic and a conductor layer stacked on the base material.

12. The power module according to any one of claims 1 to 11, wherein: The first substrate further includes a third surface located on the opposite side to the first surface in the first direction. The first facing portion has a fourth surface located on the opposite side to the first recess in the first direction. The power module further includes a cooler connected to the third surface or the fourth surface.

13. The power module according to any one of claims 1 to 12, wherein: The first facing portion has a facing surface that faces the first surface without sandwiching the first power semiconductor element. The power module further includes a joining member for joining the facing surface and the first surface.

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