JP7512659B2 - Semiconductor module and method for manufacturing the same - Google Patents

Description

The present invention relates to a semiconductor module and a method for manufacturing a semiconductor module.

Semiconductor modules have a substrate on which semiconductor elements such as IGBTs (insulated gate bipolar transistors), power MOSFETs (metal oxide semiconductor field effect transistors), and FWDs (free wheeling diodes) are mounted, and are used in inverter devices and the like (see, for example, Patent Documents 1-3).

Generally, a semiconductor module is constructed by placing a laminated substrate such as a DCB (Direct Copper Bonding) substrate on the top surface of a heat sink, and then placing a semiconductor element on the top surface of the DCB substrate. The heat sink and DCB substrate, and the DCB substrate and semiconductor element are each bonded via a bonding material such as solder. The DCB substrate is constructed from a laminated substrate in which metal layers are laminated on the top and bottom surfaces of an insulating layer such as ceramic.

JP 2001-358263 A JP 2002-050713 A JP 2014-203978 A

In a semiconductor module in which semiconductor elements are arranged on a laminated substrate such as a DCB substrate, it is necessary to ensure a creepage distance that takes into account the potential difference between the heat sink and the metal layer on the top surface of the laminated substrate, which raises concerns that the module may become larger. In addition, because the thickness from the semiconductor element to the heat sink, i.e., the heat dissipation path, is long, there is a possibility that the heat dissipation effect of the semiconductor element may not be fully realized.

The present invention has been made in consideration of these points, and one of its objectives is to provide a semiconductor module and a method for manufacturing a semiconductor module that can ensure creepage distance and improve heat dissipation.

A semiconductor module of one embodiment of the present invention comprises a heat sink, a first insulating layer arranged on an upper surface of the heat sink, a circuit board arranged on the upper surface of the first insulating layer, a semiconductor element arranged on the upper surface of the circuit board, a second insulating layer arranged between the heat sink and the first insulating layer so as to surround a lower outer peripheral end of the first insulating layer, and a frame-shaped case member surrounding the first insulating layer and the semiconductor element , wherein the second insulating layer is formed in a frame shape with a center opening, an inner peripheral end of the second insulating layer is located inside the outer peripheral end of the first insulating layer and an outer peripheral end of the second insulating layer is located outside the outer peripheral end of the first insulating layer, the first insulating layer and the second insulating layer are arranged so that at least a portion of them overlap in a planar view, the inner peripheral end of the second insulating layer is located inside the inner peripheral end of the case member and the outer peripheral end of the second insulating layer is located inside the outer peripheral end of the case member, and the second insulating layer and the case member are arranged so that at least a portion of them overlap in a planar view .

Moreover, one aspect of the present invention relates to a method for manufacturing a semiconductor module comprising a heat sink, a first insulating layer arranged on an upper surface of the heat sink, a circuit board arranged on the upper surface of the first insulating layer, and a semiconductor element arranged on the upper surface of the circuit board, the method including a second insulating layer formation step of forming a frame-shaped second insulating layer along an outer peripheral edge of the first insulating layer on the upper surface of the heat sink, a first insulating layer arrangement step of arranging the first insulating layer on the upper surface of the heat sink so as to cover an inner peripheral edge of the second insulating layer, a circuit board arrangement step of arranging the circuit board on the upper surface of the first insulating layer, a chip arrangement step of arranging the semiconductor element on the upper surface of the circuit board, and after the first insulating layer arrangement step, a case member arrangement step of arranging a frame-shaped case member surrounding the outer periphery of the first insulating layer, and in the case member arrangement step, the first insulating layer and/or the second insulating layer are sandwiched between the heat sink and the case member .

According to the present invention, it is possible to ensure the creepage distance and improve heat dissipation.

1 is a cross-sectional view of a semiconductor module according to an embodiment of the present invention. 1 is an exploded perspective view showing an example of a semiconductor module according to an embodiment of the present invention; 2 is an enlarged view of the vicinity of a portion A of the semiconductor module shown in FIG. 1 . FIG. 13 is a partial enlarged view of a semiconductor module according to a first modification. FIG. 11 is a partial enlarged view of a semiconductor module according to a second modification. FIG. 13 is a partial enlarged view of a semiconductor module according to a third modification. FIG. 13 is a partial enlarged view of a semiconductor module according to a fourth modification. FIG. 13 is a partial enlarged view of a semiconductor module according to a fifth modification. FIG. 13 is a partial enlarged view of a semiconductor module according to a sixth modification. FIG. 13 is a partial enlarged view of a semiconductor module according to a seventh modification.

A semiconductor module to which the present invention can be applied is described below. FIG. 1 is a cross-sectional view of a semiconductor module according to the present embodiment. FIG. 2 is an exploded perspective view showing an example of a semiconductor module according to the present embodiment. Note that the semiconductor module shown below is merely an example, and can be modified as appropriate without being limited thereto. Also, for the sake of convenience of explanation, some of the configuration shown in FIG. 1 is omitted in FIG. 2.

In the following figures, the direction in which the three phases constituting the inverter circuit are arranged is defined as the X direction, the direction perpendicular to the X direction (the direction in which a pair of external terminals face each other) as the Y direction, and the height direction as the Z direction. The illustrated X, Y, and Z axes are perpendicular to each other and form a right-handed system. In some cases, the X direction may be called the left-right direction, the Y direction the front-back direction, and the Z direction the up-down direction. These directions (front-back, left-right, up-down directions) are terms used for convenience of explanation, and the corresponding relationship with each of the X, Y, and Z directions may change depending on the mounting posture of the semiconductor module. For example, the heat dissipation surface side (cooler side) of the semiconductor module is referred to as the bottom side, and the opposite side is referred to as the top side. In this specification, a plan view means a view of the top surface of the semiconductor module from the positive side in the Z direction.

The semiconductor module according to this embodiment is applied to a power conversion device such as a power module, and is a power module that constitutes an inverter circuit. In FIG. 1, a single semiconductor module 1 is described. For example, when the semiconductor device constitutes a three-phase inverter circuit, three unit modules shown in FIG. 1 are arranged in the X direction in the order of U phase, V phase, and W phase (see FIG. 2).

As shown in Figures 1 and 2, the semiconductor module 1 includes a heat sink 2, a first insulating layer 3 arranged on the heat sink 2, a plurality of circuit boards 4, 5 arranged on the first insulating layer 3, a semiconductor element 6 arranged on the upper surface of a given circuit board 4, a case member 7 that houses the first insulating layer 3 and the semiconductor element 6, and a sealing resin (not shown) that is filled into the case member 7.

The heat sink 2 is a rectangular plate having an upper surface and a lower surface. In addition, the heat sink 2 has a rectangular shape in a plan view that is long in the X direction. The heat sink 2 is a metal plate made of, for example, copper, aluminum, or an alloy thereof, and the surface may be plated.

A plurality of cooling fins 20 are provided on the underside of the heat sink 2. The cooling fins 20 protrude downward in the Z direction, for example. A cooler case 21 is attached to the underside of the heat sink 2. The cooler case 21 is formed in a box shape with an open upper portion so as to cover the plurality of cooling fins 20. The cooler case 21 may be called a refrigerant jacket or a water jacket. A second insulating layer 8 formed in a rectangular frame shape is disposed on the upper surface of the heat sink 2, as will be described in detail later. One second insulating layer 8 is disposed on each phase.

On the upper surface of the heat sink 2, a first insulating layer 3 is disposed via an adhesive or the like (not shown). As shown in FIG. 2, the first insulating layer 3 has a rectangular shape in a plan view, and one is disposed in each phase. The first insulating layer 3 is disposed corresponding to the second insulating layer 8. Unlike a DCB substrate or an AMB (Active Metal Brazing) substrate, the first insulating layer 3 is formed of a relatively thin and flexible insulating sheet. For example, the first insulating layer 3 may be formed of a resin material such as epoxy, polyamide, polyimide, or liquid crystal polymer. The first insulating layer 3 may be formed of a plurality of materials selected from these resin materials. The thickness of the first insulating layer 3 is 10 μm to 200 μm, preferably 50 μm to 200 μm, as will be described in detail later. The first insulating layer 3 may be called an insulating film.

As shown in FIG. 1, a plurality of circuit boards 4 and 5 (two in FIG. 1) are arranged on the upper surface of the first insulating layer 3. The circuit boards 4 and 5 are electrically independent of each other. The circuit boards 4 and 5 are made of a metal layer of a predetermined thickness formed of copper foil or the like, and may be called, for example, a conductive layer. The circuit boards 4 and 5 have a rectangular shape in a plan view and are arranged side by side in the Y direction. The circuit boards 4 and 5 constitute a main wiring layer through which a desired electric circuit, i.e., a main current flows, via a wiring member W3 and a semiconductor element 6 described later. These circuit boards may be formed by pressing a metal plate of a predetermined thickness into a predetermined shape and pasting it on the first insulating layer 3 via an adhesive or the like. In addition, the circuit boards may be formed on the first insulating layer 3 by etching or the like.

A semiconductor element 6 is disposed on the upper surface of the circuit board 4 located on the positive side in the Y direction via a bonding material B such as solder. One semiconductor element 6 is disposed on each phase. The semiconductor element 6 is formed in a rectangular shape in a plan view from a semiconductor substrate such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN). In this embodiment, the semiconductor element 6 is configured as a RC (Reverse Conducting)-IGBT element that integrates the functions of an IGBT element and an FWD element, or a power MOSFET element.

The semiconductor element 6 is not limited to this, and may be configured by combining switching elements such as IGBTs and BJTs (bipolar junction transistors) with diodes such as FWDs. Also, as the semiconductor element 6, RB (reverse blocking)-IGBTs or the like that have sufficient voltage resistance against reverse bias may be used. The shape, number, and location of the semiconductor elements 6 may be changed as appropriate. The semiconductor element 6 in this embodiment is a vertical switching element in which functional elements such as transistors are formed on a semiconductor substrate.

A case member 7 is disposed on the upper surface of the heat sink 2, surrounding the first insulating layer 3 and the semiconductor element 6. The case member 7 has a rectangular shape in plan view that is long in the X direction, corresponding to the heat sink 2. Three openings 70 are formed in the case member 7, corresponding to each semiconductor element 6. The openings 70 have a rectangular shape in plan view that is slightly smaller than the outer periphery of the first insulating layer 3 and larger than the outer periphery of the semiconductor element 6. As a result, the case member 7 is formed in a frame shape that surrounds the first insulating layer 3 and the semiconductor element 6 for each layer, and a space is defined to accommodate the semiconductor element 6 and the sealing resin.

The case member 7 is molded, for example, from a synthetic resin and is bonded to the upper surface of the heat sink 2 via an adhesive (not shown). As will be described in detail later, the case member 7 is arranged so as to sandwich the outer peripheral edge of the first insulating layer 3 between the case member 7 and the heat sink 2 from above and below.

As shown in FIG. 1, external terminals 9 for external connection are arranged on a pair of side wall portions 71 that form part of the case member 7 and face each other in the Y direction. The external terminals 9 form external connection terminals for main current, and are formed by bending a plate-shaped body of a metal material, such as a copper material, a copper alloy material, an aluminum alloy material, or an iron alloy material, into an L-shape. The external terminals 9 are embedded in the case member 7 by integral molding. One end of the external terminals 9 forms an outer terminal portion 90 that protrudes from the upper end of the side wall portions 71. The other end of the external terminals 9 forms an inner terminal portion 91 that protrudes inward from the side wall portions 71.

The external terminal 9 and the circuit boards 4 and 5 are electrically connected by wiring members. Specifically, the inner terminal portion 91 on the positive side of the Y direction and the circuit board 4 are connected by wiring member W1. The inner terminal portion 91 on the negative side of the Y direction and the circuit board 5 are connected by wiring member W2. In addition, the circuit board 5 and the upper surface electrode of the semiconductor element 6 are electrically connected by wiring member W3.

Conductor wires (bonding wires) are used for these wiring members. The material of the conductor wires can be any one of gold, copper, aluminum, gold alloys, copper alloys, and aluminum alloys, or a combination of these. It is also possible to use materials other than conductor wires as wiring members. For example, ribbons can be used as wiring members. In addition, the wiring members may be made of metal plates formed integrally with the external terminals 9 and the circuit boards 4 and 5, as will be described in detail later.

The internal space of the case member 7 formed by the opening 70 is filled with sealing resin. The sealing resin may be filled, for example, up to the top surface of the case member 7. This seals the various components inside the case member 7 (first insulating layer 3, circuit boards 4 and 5, semiconductor element 6, wiring members W1-W3). Note that epoxy resin or silicone gel can be used as the sealing resin.

In a typical semiconductor module, a cooler is bonded to the bottom surface of a laminated substrate such as a DCB substrate via solder, and a semiconductor element is bonded to the top surface of the laminated substrate via solder. The laminated substrate is constructed by laminating metal layers on the top and bottom surfaces of an insulating layer such as ceramic, and the semiconductor element is bonded to the top surface of the metal layer on the insulating layer, which creates a problem in that the creepage distance of the semiconductor element is not sufficiently ensured. In particular, since the ceramic substrate is a relatively hard material, it may crack if it is sandwiched between the heat sink and the case, making it difficult to ensure the creepage distance. In addition, since the laminated substrate is constructed of at least three layers as described above, the heat dissipation path between the semiconductor element and the cooler becomes longer by the thickness of the laminated substrate and the thickness of the solder. As a result, there is also a problem in that the cooling effect is not fully exerted.

The inventors of the present invention have focused on the creepage distance and heat dissipation distance of the semiconductor element and have come up with the present invention. Specifically, in this embodiment, a flexible insulating sheet (first insulating layer 3) is arranged on the upper surface of the heat sink 2, rather than a laminated substrate such as a DCB substrate. A circuit board 4 is arranged on the upper surface of the first insulating layer 3, and a semiconductor element 6 is arranged on the upper surface of the circuit board 4. In addition, a second insulating layer 8 is arranged between the heat sink 2 and the first insulating layer 3 so as to surround the lower peripheral end of the first insulating layer. In other words, the first insulating layer 3 is located directly below the semiconductor element 6, and the second insulating layer 8 is located not directly below the semiconductor element 6, but at a relatively distant location on the outer periphery side of the semiconductor element 6.

With this configuration, it is possible to construct the first insulating layer 3 from an insulating sheet that is thinner than that of a DCB substrate, etc. This shortens the distance between the semiconductor element 6 and the heat sink 2, shortening the heat dissipation path. As a result, it is possible to improve heat dissipation. In addition, by disposing the second insulating layer 8 on the outer peripheral edge of the first insulating layer 3, it is possible to ensure a creepage distance that wraps around the first insulating layer and the second insulating layer 8 from the circuit board 4.

The peripheral structure of the second insulating layer 8 will now be described in detail with reference to Figures 2 and 3. Figure 3 is an enlarged view of the vicinity of part A of the semiconductor module shown in Figure 1. As shown in Figures 2 and 3, the second insulating layer 8 is formed in the shape of a rectangular frame with an opening in the center.

More specifically, a rectangular frame-shaped recess 22 is formed on the upper surface of the heat sink 2. The recess 22 is formed at a predetermined depth from the upper surface of the heat sink 2. The second insulating layer 8 is arranged so as to fill the recess 22. The upper surface of the second insulating layer 8 is flush with the upper surface of the heat sink 2. The second insulating layer 8 may be configured so that a flexible sheet material formed in a rectangular frame shape corresponding to the recess 22 is placed in the recess 22.

The second insulating layer 8 may be formed by filling the recess 22 with a paste-like resin (liquid resin) and hardening it. The second insulating layer 8 may be formed of, for example, a resin material such as epoxy, polyamide, polyimide, or liquid crystal polymer, as well as the same silicone gel as the sealing resin. The second insulating layer 8 may be formed of a plurality of materials selected from these resin materials. By forming the second insulating layer 8 by hardening a paste-like resin, it is possible to ensure the creeping distance without considering the adhesion of the case member 7 and the first insulating layer 3. In addition, it is preferable that the adhesion of the second insulating layer 8 to the case member 7 and the heat sink 2 is higher than that of the first insulating layer 3. The second insulating layer 8 may be formed of a hard insulating material such as ceramic, glass, or mica. In addition, as shown in FIG. 2, when the semiconductor module 1 has a plurality of first insulating layers 3, the plurality of second insulating layers 8 may be connected to each other. A single second insulating layer 8 on a frame may be arranged below the outer circumferential ends of the plurality of first insulating layers 3 to the extent that the creeping distance can be ensured. The second insulating layer 8 may also have discontinuous portions as long as the creepage distance can be ensured. In other words, the second insulating layer 8 may be disposed intermittently.

As shown in FIG. 3, the inner peripheral end of the second insulating layer 8 is located inside the outer peripheral end of the first insulating layer 3. Also, the outer peripheral end of the second insulating layer 8 is located outside the outer peripheral end of the first insulating layer 3. In other words, the first insulating layer and the second insulating layer are arranged so that at least a portion of them overlap in a plan view.

In addition, in terms of the relationship between the case member 7 and the second insulating layer 8, the inner peripheral end of the second insulating layer 8 is located inside the inner peripheral end of the case member 7. In addition, the outer peripheral end of the second insulating layer 8 is located inside the outer peripheral end of the case member 7. In other words, the second insulating layer 8 and the case member 7 are arranged so that at least a portion of them overlap in a plan view.

With these configurations, the second insulating layer 8 is arranged so as to be continuous with the outer peripheral edge of the first insulating layer 3, so that it is possible to ensure a sufficient creepage distance between the circuit board 4, which is a conductor, and a nearby conductor (e.g., the heat sink 2).

The outer peripheral edge of the first insulating layer 3 is located outside the inner peripheral edge of the case member 7. The outer peripheral edge of the first insulating layer 3 and the second insulating layer 8 are sandwiched between the heat sink 2 and the case member 7. In this embodiment, a flexible insulating sheet is used as the first insulating layer 3, so that even if the first insulating layer 3 is sandwiched between the case member 7 and the heat sink 2, the first insulating layer 3 will not crack. Therefore, it is possible to further ensure the creepage distance by utilizing the case member 7, which is an insulator.

The semiconductor module 1 thus configured can be manufactured by the following method. Specifically, the manufacturing method of the semiconductor module 1 according to the present embodiment includes the following steps, as shown in FIGS.
(1) a second insulating layer forming step of forming a frame-shaped second insulating layer 8 along the outer circumferential edge of the first insulating layer 3 on the upper surface of the heat sink 2;
(2) a first insulating layer arranging step of arranging a first insulating layer 3 on the upper surface of the heat sink 2 so as to cover the inner peripheral end of the second insulating layer 8;
(3) a circuit board placement step of placing a circuit board 4 on the upper surface of the first insulating layer 3;
(4) a chip placement step of placing a semiconductor element 6 on the upper surface of the circuit board 4;
(5) After the first insulating layer arranging step, a case member arranging step is performed in which a frame-shaped case member 7 surrounding the outer periphery of the first insulating layer 3 is arranged.

The above steps (1) to (5) may be carried out in a reverse order, provided that no contradiction occurs. For example, the first insulating layer arrangement step (2) may be carried out after the circuit board arrangement step (3). In this case, in the first insulating layer arrangement step, the first insulating layer 3 having the circuit board 4 arranged on its upper surface is arranged on the upper surface of the heat sink 2. In addition, in the case member arrangement step (5), it is preferable to sandwich the first insulating layer 3 and/or the second insulating layer 8 between the heat sink and the case member. In addition, various methods such as pressure, heating, and adhesion can be used in the arrangement steps of each member.

As described above, in this embodiment, the first insulating layer 3 is disposed on the upper surface of the heat sink 2, and the second insulating layer 8 is disposed between the heat sink 2 and the first insulating layer 3 so as to surround the lower outer edge of the first insulating layer, thereby ensuring the creepage distance and improving heat dissipation.

Next, modified examples will be described with reference to Figs. 4 to 10. Fig. 4 is a partially enlarged view of a semiconductor module according to a first modification. Fig. 5 is a partially enlarged view of a semiconductor module according to a second modification. Fig. 6 is a partially enlarged view of a semiconductor module according to a third modification. Fig. 7 is a partially enlarged view of a semiconductor module according to a fourth modification. Fig. 8 is a partially enlarged view of a semiconductor module according to a fifth modification. Fig. 9 is a partially enlarged view of a semiconductor module according to a sixth modification. Fig. 10 is a partially enlarged view of a semiconductor module according to a seventh modification.

In the above embodiment, a recess 22 is formed on the upper surface of the heat sink 2, and the second insulating layer 8 is arranged so as to fill the recess 22. However, the present invention is not limited to this configuration. The configuration shown in FIG. 4 may be used. As shown in FIG. 4, the second insulating layer 8 may be directly arranged (applied) on the upper surface of the heat sink 2, and the outer peripheral edge of the first insulating layer 3 may be arranged so as to cover at least a part of the second insulating layer 8. By using a paste-like resin for the second insulating layer 8, it is possible to form a gently curved outer surface as shown in FIG. 4. In addition, since the first insulating layer 3 has flexibility, it is possible for the outer peripheral edge of the first insulating layer 3 to cover the upper surface of the second insulating layer 8 without any gaps, regardless of the outer surface shape of the second insulating layer 8. In addition, by using a paste-like resin as the second insulating layer 8, it is possible to further increase the adhesion of the second insulating layer 8 to the first insulating layer 3, the case member 7, and the heat sink 2.

In the above embodiment, the first insulating layer 3 is sandwiched between the case member 7 and the heat sink 2, but this is not a limitation. The configuration shown in FIG. 5 is also possible. As shown in FIG. 5, the first insulating layer 3 does not have to be sandwiched between the case member 7 and the heat sink 2. Specifically, the outer peripheral end of the first insulating layer 3 is located inside the inner peripheral end of the case member 7. Only the second insulating layer 8 is sandwiched between the heat sink 2 and the case member 7. Even with this configuration, it is possible to increase the adhesion between the first insulating layer 3 and the second insulating layer 8, and between the case member 7 and the second insulating layer 8, and ensure the creepage distance.

As shown in FIG. 6, the case member 7 may be provided with a protrusion 72 for positioning. The protrusion 72 is provided at a location corresponding to the recess 22 on the heat sink 2. More specifically, the protrusion 72 protrudes downward from the lower surface of the case member 7. The protrusion 72 may be formed in a rectangular frame shape in plan view corresponding to the recess 22. The protrusion 72 may also be arranged so that multiple pins are arranged in a rectangular shape in plan view at a predetermined interval. It is preferable that the tip of the protrusion 72 enters the recess 22 and its side surface abuts against the inner surface on the outer periphery of the recess 22. This makes it easier to position the case member 7 when it is attached, and improves assembly efficiency.

Also, as shown in FIG. 7, when the positioning protrusion 72 is engaged with the recess 22, the tip of the protrusion 72 may be configured to push down the outer peripheral end 30 of the first insulating layer 3. That is, the outer peripheral end 30 of the first insulating layer 3 is pushed down by the protrusion 72 and a part of it enters the recess 22. At this time, it is preferable that the second insulating layer 8 in the recess 22 is a paste-like resin before hardening. With these configurations, it is possible to improve the adhesion between the first insulating layer 3 and the second insulating layer 8 while facilitating the positioning of the case member 7.

Also, as shown in FIG. 8, by roughening the upper surface of the heat sink 2, it is possible to improve the adhesion when bonding the first insulating layer 3 to the heat sink 2. Specifically, on the upper surface of the heat sink 2, numerous uneven portions 23 are formed at locations corresponding to the first insulating layer 3. The uneven portions 23 are formed by roughening the upper surface of the heat sink 2 by etching or blasting. In addition, it is preferable that the uneven portions 23 are formed in a range inside the outer peripheral edge of the second insulating layer 8. By not extending the range of the uneven portions 23 to the outer peripheral edge of the second insulating layer 8, it is possible to suppress the fluidity when the paste-like resin is applied. In other words, the uneven portions 23 make it easier for the paste-like resin to spread, and this is intended to prevent this.

In the above embodiment, the wiring member W1 (wiring member W2) connecting the external terminal 9 and the circuit board 4 (circuit board 5) is described as being composed of a conductor wire, but this configuration is not limited thereto. For example, as shown in FIG. 9, the circuit board, the external terminal, and the wiring member may be composed of an integrally molded metal plate 92. Specifically, the metal plate 92 is formed by folding multiple times and is embedded in the case member 7 by integral molding. The metal plate 92 has an external terminal portion 93 whose one end protrudes from the upper surface of the case member 7, a circuit board 94 whose other end is joined to the upper surface of the first insulating layer 3, and a connecting portion 95 that connects the external terminal portion 93 and the circuit board 94. By using the integrated metal plate 92, it is possible to reduce the number of parts of the semiconductor module 1 and the assembly man-hours.

Also, as shown in FIG. 10, a second recess 24 for accommodating the first insulating layer 3 may be formed on the upper surface of the heat sink 2 separately from the recess 22. More specifically, a second recess 24 of a predetermined depth is formed on the upper surface of the heat sink 2 corresponding to the first insulating layer 3. The second recess 24 has a rectangular shape in a plan view. The depth of the second recess 24 is preferably greater than the thickness of the first insulating layer 3. This makes it possible to reduce the protruding height of the first insulating layer 3, and to achieve a low profile for the entire module. In addition, a recess 22 having a step formed in a crank shape in a cross-sectional view is formed on the outer periphery of the second recess 24. The first insulating layer 3 is accommodated in the second recess 24, and the second insulating layer 8 is disposed in the recess 22. In this case, the second insulating layer 8 may be composed of a sheet previously molded to match the shape of the recess 22, or a paste-like resin may be applied along the recess 22.

In addition, in the above embodiment, the number and placement of the semiconductor elements are not limited to the above configuration and can be changed as appropriate.

In addition, in the above embodiment, the number and layout of the circuit boards are not limited to the above configuration and can be changed as appropriate.

In addition, in the above embodiment, the first insulating layer 3, the circuit boards 4 and 5, and the semiconductor element 6 are configured to be rectangular or square in plan view, but are not limited to this configuration. These configurations may be formed into polygonal shapes other than those described above.

In the above embodiment, the semiconductor module 1 is configured by arranging three unit modules in the X direction in the order of U-phase, V-phase, and W-phase, but is not limited to this configuration. The number and direction of the unit modules can be changed as appropriate. In addition, the case member 7 is formed by integrating the three phases of U-phase, V-phase, and W-phase, but is not limited to this and can be changed as appropriate. The case member 7 may be provided separately for each unit module.

Furthermore, although the present embodiment and its modified examples have been described, other embodiments may be combinations of the above embodiments and modified examples in whole or in part.

Furthermore, the present embodiment is not limited to the above-mentioned embodiment and modifications, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or derived other technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea.

The features of the above embodiment are summarized below.
The semiconductor module described in the above embodiment comprises a heat sink, a first insulating layer arranged on an upper surface of the heat sink, a circuit board arranged on the upper surface of the first insulating layer, a semiconductor element arranged on the upper surface of the circuit board, and a second insulating layer arranged between the heat sink and the first insulating layer so as to surround the lower outer edge of the first insulating layer.

In the semiconductor module described in the above embodiment, the second insulating layer is formed in a frame shape with an opening in the center, the inner peripheral edge of the second insulating layer is located inside the outer peripheral edge of the first insulating layer, the outer peripheral edge of the second insulating layer is located outside the outer peripheral edge of the first insulating layer, and the first insulating layer and the second insulating layer are arranged so that at least a portion of them overlap in a plan view.

The semiconductor module described in the above embodiment further includes a frame-shaped case member surrounding the first insulating layer and the semiconductor element, the inner peripheral end of the second insulating layer is located inside the inner peripheral end of the case member, the outer peripheral end of the second insulating layer is located inside the outer peripheral end of the case member, and the second insulating layer and the case member are arranged so that at least a portion of them overlap in a plan view.

In the semiconductor module described in the above embodiment, the outer peripheral end of the first insulating layer is located outside the inner peripheral end of the case member, and the outer peripheral end of the first insulating layer and the second insulating layer are sandwiched between the heat sink and the case member.

In the semiconductor module described in the above embodiment, the outer peripheral edge of the first insulating layer is located inside the inner peripheral edge of the case member, and the second insulating layer is sandwiched between the heat sink and the case member.

In the semiconductor module described in the above embodiment, the case member has an external terminal for external connection, and further includes a wiring member that electrically connects the circuit board and the external terminal, and the circuit board, the external terminal, and the wiring member are composed of an integrally molded metal plate.

In the semiconductor module described in the above embodiment, the first insulating layer is composed of a flexible insulating sheet.

In the semiconductor module described in the above embodiment, the second insulating layer is disposed on the upper surface of the heat sink, and the first insulating layer is disposed such that its outer peripheral edge covers at least a portion of the second insulating layer.

In the semiconductor module described in the above embodiment, the second insulating layer is formed from an insulating sheet or by hardening a liquid resin.

In the semiconductor module described in the above embodiment, the heat sink has a frame-shaped recess formed on the upper surface along the outer peripheral edge of the first insulating layer, and the second insulating layer is arranged to fill the recess.

The semiconductor module described in the above embodiment further includes a frame-shaped case member that surrounds the first insulating layer and the semiconductor element, and the case member has a protrusion provided at a location corresponding to the recess.

In the semiconductor module described in the above embodiment, the outer peripheral edge of the first insulating layer is pressed down by the protrusion and part of it fits into the recess.

In the semiconductor module described in the above embodiment, the upper surface of the heat sink has numerous irregularities formed in areas corresponding to the first insulating layer.

In the semiconductor module described in the above embodiment, the uneven portion is formed in an area inside the outer peripheral edge of the second insulating layer.

In the semiconductor module described in the above embodiment, a second recess is formed on the upper surface of the heat sink, and the first insulating layer is accommodated in the second recess.

In the semiconductor module described in the above embodiment, the thickness of the first insulating layer is 50 μm to 200 μm.

In the semiconductor module described in the above embodiment, the first insulating layer is formed of an insulating material including epoxy, polyamide, polyimide, or liquid crystal polymer.

The manufacturing method of the semiconductor module described in the above embodiment is a manufacturing method of a semiconductor module including a heat sink, a first insulating layer arranged on the upper surface of the heat sink, a circuit board arranged on the upper surface of the first insulating layer, and a semiconductor element arranged on the upper surface of the circuit board, and includes a second insulating layer forming process for forming a frame-shaped second insulating layer along the outer peripheral edge of the first insulating layer on the upper surface of the heat sink, a first insulating layer arranging process for arranging the first insulating layer on the upper surface of the heat sink so as to cover the inner peripheral edge of the second insulating layer, a circuit board arranging process for arranging the circuit board on the upper surface of the first insulating layer, and a chip arranging process for arranging the semiconductor element on the upper surface of the circuit board.

In the method for manufacturing a semiconductor module described in the above embodiment, in the first insulating layer arrangement step, the first insulating layer having the circuit board arranged on its upper surface is arranged on the upper surface of the heat sink.

The method for manufacturing a semiconductor module described in the above embodiment further includes a case member arrangement process for arranging a frame-shaped case member surrounding the outer periphery of the first insulating layer after the first insulating layer arrangement process, and in the case member arrangement process, the first insulating layer and/or the second insulating layer is sandwiched between the heat sink and the case member.

As described above, the present invention has the effect of ensuring creepage distance and improving heat dissipation, and is particularly useful for semiconductor modules and methods for manufacturing semiconductor modules.

1: Semiconductor module 2: Heat sink 3: First insulating layer 4: Circuit board 5: Circuit board 6: Semiconductor element 7: Case member 8: Second insulating layer 9: External terminal 20: Cooling fin 21: Cooler case 22: Recess 23: Uneven portion 24: Second recess 30: Outer peripheral edge 70: Opening 71: Side wall portion 72: Protrusion 90: Outer terminal portion 91: Inner terminal portion 92: Metal plate 93: External terminal portion 94: Circuit board 95: Connection portion B: Bonding material W1: Wiring member W2: Wiring member W3: Wiring member

Claims (17)

A heat sink;
A first insulating layer disposed on an upper surface of the heat sink;
a circuit board disposed on an upper surface of the first insulating layer;
a semiconductor device disposed on an upper surface of the circuit board;
a second insulating layer disposed between the heat sink and the first insulating layer so as to surround a lower portion of an outer circumferential end of the first insulating layer;
a frame-shaped case member that surrounds the first insulating layer and the semiconductor element ,
The second insulating layer is formed in a frame shape with an opening in the center,
an inner peripheral end of the second insulating layer is located inside an outer peripheral end of the first insulating layer;
an outer circumferential edge of the second insulating layer is located outside an outer circumferential edge of the first insulating layer;
the first insulating layer and the second insulating layer are arranged so as to at least partially overlap each other in a plan view;
an inner circumferential end of the second insulating layer is located inside an inner circumferential end of the case member,
an outer circumferential edge of the second insulating layer is located inside an outer circumferential edge of the case member;
The second insulating layer and the case member are arranged so as to at least partially overlap each other in a plan view . an outer circumferential end of the first insulating layer is located outside an inner circumferential end of the case member,
The semiconductor module according to claim 1 , wherein the outer peripheral edge of the first insulating layer and the second insulating layer are sandwiched between the heat sink and the case member. an outer circumferential end of the first insulating layer is located inside an inner circumferential end of the case member,
The semiconductor module according to claim 1 , wherein the second insulating layer is sandwiched between the heat sink and the case member. the case member has an external terminal for external connection,
a wiring member electrically connecting the circuit board and the external terminal;
4. The semiconductor module according to claim 1 , wherein the circuit board, the external terminals, and the wiring members are formed from an integrally molded metal plate. 5. The semiconductor module according to claim 1, wherein the first insulating layer is made of a flexible insulating sheet. the second insulating layer is disposed on an upper surface of the heat sink;
6. The semiconductor module according to claim 1, wherein the first insulating layer is disposed such that an outer peripheral edge of the first insulating layer covers at least a portion of the second insulating layer. 7. The semiconductor module according to claim 1, wherein the second insulating layer is formed by an insulating sheet or by hardening a liquid resin. the heat sink has a frame-shaped recess formed on an upper surface thereof along an outer peripheral edge of the first insulating layer,
The semiconductor module according to claim 1 , wherein the second insulating layer is disposed so as to fill the recess. The semiconductor module according to claim 8 , wherein the case member has a protrusion provided at a location corresponding to the recess. 10. The semiconductor module according to claim 9 , wherein an outer peripheral edge of the first insulating layer is pressed down by the protrusion so that a portion of the outer peripheral edge is inserted into the recess. 11. The semiconductor module according to claim 1, wherein an upper surface of said heat sink has a number of projections and recesses formed in areas corresponding to said first insulating layer. The semiconductor module according to claim 11 , wherein the uneven portion is formed in an area inside an outer circumferential edge of the second insulating layer. 13. The semiconductor module according to claim 1, wherein a second recess in which the first insulating layer is accommodated is formed on an upper surface of the heat sink. 14. The semiconductor module according to claim 1, wherein the first insulating layer has a thickness of 50 μm to 200 μm. 15. The semiconductor module according to claim 1, wherein the first insulating layer is formed of an insulating material containing epoxy, polyamide, polyimide, or liquid crystal polymer. A heat sink;
A first insulating layer disposed on an upper surface of the heat sink;
a circuit board disposed on an upper surface of the first insulating layer;
a semiconductor element disposed on an upper surface of the circuit board,
a second insulating layer forming step of forming a frame-shaped second insulating layer on the upper surface of the heat sink along an outer peripheral edge of the first insulating layer;
a first insulating layer disposing step of disposing the first insulating layer on the upper surface of the heat sink so as to cover an inner peripheral end of the second insulating layer;
a circuit board placement step of placing the circuit board on an upper surface of the first insulating layer;
a chip placement step of placing the semiconductor element on an upper surface of the circuit board;
a case member arranging step of arranging a frame-shaped case member surrounding an outer periphery of the first insulating layer after the first insulating layer arranging step ,
A method for manufacturing a semiconductor module , wherein in the case member arrangement step, the first insulating layer and/or the second insulating layer is sandwiched between the heat sink and the case member . The method for manufacturing a semiconductor module according to claim 16 , wherein in the first insulating layer arranging step, the first insulating layer having the circuit board arranged on an upper surface thereof is arranged on an upper surface of the heat sink.

Images