Power Module

Abstract

To provide a power module with high reliability.SOLUTION: A power module 100 comprises a base plate, a housing, a board unit U1 disposed on the base plate, a terminal board 80, a first resin layer 91, and a second resin layer 92. The board unit U1 has a board 20 fixed onto the base plate 10, a dam part 40, a semiconductor chip 30, a metal member 50, and a wire 60. Viewing from above, the dam part 40 is formed along an edge of the board 20. The first resin layer 91 is provided inside the dam part 40. The second resin layer 92 is provided on the first resin layer 91, and an upper surface of the metal member 50 is located inside the second resin layer. The elastic modulus of the second resin layer 92 is lower than that of the first resin layer 91.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to a power module. [Background technology]

[0002] Power modules have been developed that have a semiconductor chip for power control inside a housing and connect a terminal board to the semiconductor chip from outside the housing to input and output power. In such power modules, the inside of the housing is filled with an insulating sealant to keep the internal circuit and the terminal board in an insulated state. The amount of current passing through power modules is expected to increase further in the future, and measures to prevent heat generation due to current passing have become an issue. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-16629 A Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE PRESENT EMBODIMENTS The present invention provides a highly reliable power module. [Means for solving the problem]

[0005] The power module according to the embodiment includes a base plate, a housing, at least one substrate unit, a terminal plate, a first resin layer, and a second resin layer. The housing is provided on the base plate. The substrate unit is disposed on the base plate. The substrate unit has a substrate, a dam portion, a first semiconductor chip, a metal member, and a first wire. The substrate is fixed on the base plate and has a plurality of electrode plates including at least a first and a second electrode plate on the upper surface. The dam portion is provided on the substrate and is formed along an edge of the substrate when viewed from above. The first semiconductor chip is provided on the first electrode plate and has a first electrode. The metal member is provided on any of the electrode plates. The first wire has an electrode plate connection portion, a chip connection portion, and a curved portion. The electrode plate connection portion is connected to the second electrode plate. The chip connection portion is connected to the first electrode. The curved portion is located between the electrode plate connection portion and the chip connection portion. The terminal plate is joined to the upper surface of the metal member. The first resin layer is provided on the substrate inside the dam portion. The first resin layer has the chip connection portion and the electrode plate connection portion disposed therein. The second resin layer is provided on the first resin layer and the dam portion. The second resin layer has the upper surface of the metal member disposed therein. The second resin layer has a lower elastic modulus than the first resin layer. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a plan view showing a power module according to an embodiment. [Diagram 2] 2 is a cross-sectional view taken along line AA' shown in FIG. [Diagram 3] FIG. 3 is a partially enlarged cross-sectional view of FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view showing the internal dimensions of the power module according to the embodiment. [Diagram 5] 5(a) and 5(b) are cross-sectional views showing a method for manufacturing a power module according to an embodiment. [Figure 6] 5(a) and 5(b) are cross-sectional views showing a method for manufacturing a power module according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment will be described with reference to the drawings. The drawings are schematic, and the dimensional ratios of each part and the ratios of the sizes of the parts are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. Furthermore, in this specification and each drawing, elements similar to those described above with respect to the previous drawings are given the same reference numerals, and detailed descriptions are omitted as appropriate.

[0008] Fig. 1 is a plan view showing a power module according to an embodiment. Fig. 2 is a cross-sectional view taken along line A-A' shown in Fig. 1. Fig. 3 is a partially enlarged cross-sectional view of Fig. 2. Fig. 4 is a cross-sectional view showing internal dimensions of the power module according to this embodiment. Figs. 1 to 4 omit the upper surface of a housing 11, which will be described later. Fig. 1 shows only a schematic configuration for the sake of simplicity.

[0009] 1 and 2, the overall shape of the power module 100 of this embodiment is a substantially rectangular parallelepiped. The power module 100 has a housing 11, a base plate 10, a substrate unit U1, a terminal board 80, a first resin layer 91, and a second resin layer 92.

[0010] 2, the base plate 10 has a generally plate-like shape with an upper surface 10A and a bottom surface. The bottom surface of the base plate 10 constitutes, for example, the bottom surface of the power module 100. The base plate 10 is formed of, for example, ceramic containing aluminum (Al), silicon (Si), and carbon (C), and more specifically, is formed of a metal-based ceramic composite material (AlSiC).

[0011] The housing 11 is composed of a side portion 11a constituting the side surface and a top surface constituting the top surface, and is hollow inside. The housing 11 constitutes, for example, the side surface and the top surface of the power module 100. The housing 11 is formed, for example, from an insulating resin material. As shown in FIG. 2, the side portion 11a is fixed to an end portion of the top surface 10A of the base plate 10, for example, with an adhesive. As a result, the top surface 10A of the base plate 10 excluding the end portion is exposed to the internal space of the housing 11.

[0012] For ease of explanation, in Fig. 2, the direction along the long side of the top surface 10A of the base plate 10 is defined as the X direction. The direction perpendicular to the X direction and along the short side of the top surface 10A is defined as the Y direction. The direction perpendicular to the XY plane is defined as the Z direction. In addition, for the sake of convenience in the explanation, "up" and "down" refer to the direction from the base plate 10 toward the internal space of the housing 11 in the Z direction as up, and the opposite direction as down, but this expression is also for convenience and does not necessarily coincide with the direction of gravity.

[0013] As shown in Fig. 1, for example, four board units U1 are provided on a base plate 10. The four board units U1 are arranged, for example, in a matrix of two rows and two columns. As shown in Figs. 1 and 2, the four board units U1 are provided on the base plate 10 and, for example, are spaced apart from one another and, for example, from a side portion 11a of a housing 11. The board unit U1 has a board 20, a semiconductor chip 30 (a first semiconductor chip in the claims), a dam portion 40, a metal member 50, and wires 61, 62, and 63 (hereinafter, sometimes collectively referred to as "wires 60").

[0014] 1 and 2, the substrate 20 has, for example, a substantially plate shape. The substrate 20 has a base body 21, an electrode plate 22, and a back electrode plate 23. The base 21 includes, for example, silicon (Si) and nitrogen (N), such as silicon nitride (SiC). The base 21 has, for example, a plate shape, and the top surface 21A and the bottom surface of the base 21 are flat surfaces.

[0015] 2, the electrode plates 22 are provided on the upper surface 21A of the base 21, are spaced apart from each other, and form a predetermined wiring shape. The electrode plates 22 include, for example, electrode plates 22a, 22b, 22c, 22d, and 22e.

[0016] The back electrode plate 23 is provided on the bottom surface of the base 21. As shown in Fig. 2, the back electrode plate 23 has a planar shape that is, for example, approximately similar to and slightly smaller than the bottom surface of the base 21. The back electrode plate 23 covers the bottom surface of the base 21 except for the edges. The back electrode plate 23 of the substrate 20 is fixed to the upper surface 10A of the base plate 10 by, for example, soldering. As a result, the substrate unit U1 is provided on the upper surface 10A of the base plate 10.

[0017] The electrode plates 22a, 22b, 22c, 22d, and 22e and the back electrode plate 23 are formed, for example, by punching out the same copper plate, and the thicknesses of the electrode plates 22a, 22b, 22c, 22d, and 22e (hereinafter simply referred to as the thickness of the electrode plate 22) are, for example, the same as the thickness of the back electrode plate 23. In addition, the upper surface of the substrate 20 is, in detail, an uneven surface consisting of the upper and side surfaces of the electrode plate 22 and the upper surface 21A of the base body 21, and is a surface approximately parallel to the upper surface 10A of the base plate 10.

[0018] The semiconductor chip 30 is a semiconductor chip that controls the amount of current, such as a MOSFET, and a semiconductor chip that has a rectifying function, such as a diode. As shown in Fig. 3, the semiconductor chip 30 has an upper electrode 31 and a back electrode 32. The upper electrode 31 is exposed on the upper surface of the semiconductor chip 30. The back electrode 32 is exposed on the bottom surface of the semiconductor chip 30. A wire 61 (first wire in the claims) is connected to the upper electrode 31, for example, by ultrasonic bonding. The back electrode 32 is fixed and connected to the upper surface of the electrode plate 22a (first electrode plate in the claims) by, for example, soldering.

[0019] 2 and 3, the metal member 50 is disposed on the upper surface of the electrode plate 22c. The metal member 50 has, for example, a substantially rectangular parallelepiped shape and has a top surface 50A, side surfaces, and a bottom surface. The bottom surface of the metal member 50 is disposed within the upper surface of the electrode plate 22c at the installation location. The metal member 50 is joined to the electrode plate 22c by, for example, soldering. The metal member 50 includes, for example, copper.

[0020] 1 and 2, the dam portion 40 is provided on the upper surface of the substrate 20, more specifically, on the upper surface 21A of the base 21. The dam portion 40 is provided along the edge of the substrate 20. As shown in FIGS. 1 and 2, the dam portion 40 has a closed fence shape that is arranged on the inner periphery on the edge side of the substrate 20 when viewed from above. In this way, since the dam portion 40 is provided in the frame-shaped region along the edge side of the upper surface 21A of the base 21, for example, the electrode plate 22 is not provided.

[0021] As shown in FIG. 3, the dam portion 40 has three bulging portions 40a bulging in the direction X or the direction Y, and two constricted portions 40b between the bulging portions 40a. The inner and outer surfaces of the dam portion 40 are uneven surfaces. The bulging portions 40a of the dam portion 40 on the short sides shown in FIG. 3 bulge in the direction X, whereas the bulging portions 40a of the dam portion 40 on the long sides bulge in the direction Y. The number of stages of the bulging portions 40a is not limited to three, and may be two or less or four or more. In addition, there are cases where the bulging portions 40a and the constricted portions 40b are not clearly distinguishable. The dam portion 40 includes, for example, polymer silicone, is, for example, a polymer silicone resin, or is, for example, a hardened silicone adhesive. The elastic modulus of the dam portion 40 is, for example, about 10 MPa.

[0022] The wire 60 is made of, for example, aluminum (Al) and has a thin wire shape. As shown in Fig. 2, the wire 60 includes wires 61 and 62 that connect the inside of the board unit U1 and a wire 63 (a second wire in the claims) that connects between the board units U1. The lengths of the wire 61 and the wire 62 are approximately the same, and the length of the wire 63 is, for example, longer than the wires 61 and 62. The diameters of the wires 61, 62, and 63 are, for example, the same.

[0023] As shown in FIG. 3, the wire 61 is disposed inside the substrate unit U1. The wire 61 connects the upper surface electrode 31 of the semiconductor chip 30 to a predetermined electrode plate 22b (second electrode plate in the claims). The wire 61 has a chip connection portion 61a provided at one end, an electrode plate connection portion 61b provided at the other end, and a curved portion 61c. The chip connection portion 61a is connected to the upper surface electrode 31 of the semiconductor chip 30. The electrode plate connection portion 61b is connected to the electrode plate 22b. The curved portion 61c is a portion curved upward between the chip connection portion 61a and the electrode plate connection portion 61b.

[0024] As shown in Fig. 2, wire 62 is disposed inside substrate unit U1. Wire 62 connects between electrode plate 22d and electrode plate 22e. Wire 62 has electrode plate connection parts 62b and curved part 62c provided at both ends. Two electrode plate connection parts 62b are connected to electrode plates 22d and 22e, respectively. Curved part 62c is a part curved upward between two electrode plate connection parts 62b.

[0025] 2, the wire 63 is disposed across, for example, adjacent first and second board units U11 and U12 of the four board units U1. The wire 63 has electrode plate connection portions 63b provided at both ends and a curved portion 63c (referred to as an intermediate portion in the claims). One of the electrode plate connection portions 63b is connected to the electrode plate 22c of the first board unit U11. The other electrode plate connection portion 63b is connected to the electrode plate 22a of the second board unit U12.

[0026] 2, the electrode plate 22c of the first substrate unit U11 is disposed in a portion adjacent to the dam portion 40 in the first substrate unit U11 and is adjacent to the second substrate unit U12. The electrode plate 22a of the second substrate unit U12 is disposed in a portion adjacent to the dam portion 40 in the second substrate unit U12 and is adjacent to the first substrate unit U11. The curved portion 63c of the wire 63 is disposed across the dam portion 40 of the first substrate unit U11 and the dam portion 40 of the second substrate unit U12.

[0027] The chip connection portion 61a and the electrode plate connection portions 61b, 62b, and 63b are connected by, for example, ultrasonic bonding, whereby the chip connection portion 61a and the electrode plate connection portions 61b, 62b, and 63b are hardened by alloying, and may take on, for example, a bulging spherical shape.

[0028] The height of each component from the upper surface of the substrate 20 will be described below. In order to standardize the standard for height, the "height from the upper surface of the substrate 20" is specifically the height based on the upper surface 21A of the base 21 not including the electrode plate 22. Furthermore, when the term "height" is simply used for each component, it refers to the height from the upper surface of the substrate 20. Furthermore, the height of a certain part refers to the height of the top end of that part.

[0029] 4, the height H61a of the chip connection portion 61a is higher than the height H61b of the electrode plate connection portion 61b, the height H62b of the electrode plate connection portion 62b, and the height H63b of the electrode plate connection portion 63b by, for example, the thickness of the semiconductor chip 30. The height H61a of the chip connection portion 61a is, for example, approximately the same as the sum of the thickness of the electrode plate 22, the thickness of the semiconductor chip 30, and the diameter of the wire 61. The thickness is the length in the direction Z. The height H61b of the electrode plate connection portion 61b, the height H62b of the electrode plate connection portion 62b, and the height H63b of the electrode plate connection portion 63b are approximately the same as the sum of the thickness of the electrode plate 22 and the diameters of the wires 61, 62, and 63. The heights H61b, H62b, and H63b are approximately the same as each other. A height H61c of the curved portion 61c is higher than a height H62c of the curved portion 62c and lower than a height H63c of the curved portion 63c.

[0030] The height H40 of the dam portion 40 is higher than the height H61a of the chip connection portion 61a. The height H40 of the dam portion 40 may be lower than the height H50A of the upper surface 50A of the metal member 50. The height H50A of the upper surface 50A of the metal member 50 is, for example, approximately the same as the sum of the thickness of the electrode plate 22 and the thickness of the metal member 50. The height H40 of the dam portion 40 may be lower than the height H61 of the curved portion 61c of the wire 61, lower than the height H63c of the curved portion 63c of the wire 63, and higher than the height H62c of the curved portion 62c of the wire 62.

[0031] 1 and 2, terminal board 80 has external connection terminal boards 81 and 82 and multiple internal wiring terminal boards 83. External connection terminal boards 81 and 82 receive power from an external power source and output the power converted by multiple semiconductor chips 30 to the outside. Internal wiring terminal board 83 transmits signals inside power module 100, for example.

[0032] 2, external connection terminal board 82 and internal wiring terminal board 83 are held in advance by, for example, being integrally molded on side surface portion 11a of housing 11. External connection terminal board 81 is held by being sandwiched between side surface portion 11a and the top surface portion of housing 11. As shown in FIG. 2, external connection terminal boards 81, 82 and internal wiring terminal board 83 (hereinafter sometimes collectively referred to as "terminal boards 80") are arranged in plurality in the internal space of housing 11.

[0033] In this embodiment, the terminal board 80 will be described in detail below using one external connection terminal board 82 as an example. As shown in FIG. 3, the external connection terminal board 82 has a joint portion 82a (hereinafter, sometimes collectively referred to as "joint portion 80a"), a curved portion 82b (hereinafter, sometimes collectively referred to as "curved portion 80b"), a wiring portion 82c (hereinafter, sometimes collectively referred to as "wiring portion 80c"), and an extraction portion 82d.

[0034] The joint portion 82a is an end portion of the external connection terminal board 82, and is connected to the upper surface 50A of the metal member 50 and is substantially parallel to the upper surface 50A. The joint portion 82a is joined to the upper surface 50A of the metal member 50 by, for example, ultrasonic bonding.

[0035] The curved portion 82b is connected to the joint portion 82a and is curved upward from a direction parallel to the upper surface 50A. The wiring portion 82c extends upward from the curved portion 82b and is routed within the internal space of the housing 11. The lead-out portion 82d is a portion that is led out from the wiring portion 82c to the outside of the housing 11.

[0036] 2, the first resin layer 91 and the second resin layer 92 are sealing materials. The first resin layer 91 contains, for example, an epoxy resin. The second resin layer 92 contains, for example, polymer silicone, is an insulating gel-like resin, and is, for example, transparent or translucent. The first resin layer 91 and the second resin layer 92 are insulating.

[0037] As shown in Figs. 2 and 3, the first resin layer 91 is provided on the substrate unit U1. The first resin layer 91 is provided on the substrate 20 and inside the dam portion 40, filling the inside of the dam portion 40. Therefore, the bottom surface of the first resin layer 91 contacts the upper surface 20A of the substrate 20, and does not contact the upper surface 10A of the base plate 10. The area occupied by the first resin layer 91 is smaller than the area of ​​the substrate 20. In addition, the first resin layer 91 contacts the inner surface of the dam portion 40, which is an uneven surface. As a result, the side surface of the first resin layer 91 is an uneven surface.

[0038] 4, the height H91 of the first resin layer 91 is the same as or less than the height H40 of the dam portion 40. The height H91 of the first resin layer 91 is higher than the height H61a of the chip connecting portion 61a and lower than the height H50A of the upper surface 50A of the metal member 50. The first resin layer 91 includes the chip connecting portion 61a but does not include the upper surface 50A of the metal member 50.

[0039] 2 and 3, the first resin layer 91 is in contact with the side surface of the metal member 50, the top surface and side surfaces of the semiconductor chip 30, as well as the chip connection portion 61a, the electrode plate connection portions 61b, 62b, and 63b, and the curved portion 62c of the wire 62. The first resin layer 91 does not include the curved portion 61c of the wire 61 and the curved portion 63c of the wire 63, and is not in contact with the curved portions 61c and 63c.

[0040] The height H91 of the first resin layer 91 is higher than the height H61b of the electrode plate connecting portion 61b, the height H62b of the electrode plate connecting portion 62b, and the height H63b of the electrode plate connecting portion 63b. The height H91 of the first resin layer 91 is lower than the height H61c of the curved portion 61c of the wire 61 and the height H63c of the curved portion 63c of the wire 63, and is higher than the height H62c of the curved portion 62c of the wire 62. Therefore, the curved portion 61c of the wire 61 and the curved portion 63c of the wire 63 protrude from the upper surface of the first resin layer 91 and are disposed outside the first resin layer 91.

[0041] 2, the second resin layer 92 fills the internal space of the housing 11, and embeds the board unit U1 together with the first resin layer 91. Therefore, the second resin layer 92 is also provided on the first resin layer 91 and the board unit U1. The curved portion 61c of the wire 61 and the curved portion 63c of the wire 63 are disposed within the second resin layer 92. The second resin layer 92 is also provided in the gap between the side portion 11a of the housing 11 and the board unit U1, and in the gap between adjacent board units U1 among the four board units U1.

[0042] The bottom surface of the second resin layer 92 contacts the upper surface of the first resin layer 91, the upper part of the dam portion 40, and the upper surface 10A of the base plate 10. The locations where the second resin layer 92 contacts the upper surface 10A of the base plate 10 are the gaps between the side surface portion 11a and the four board units U1, and the gaps between two adjacent board units U1. The second resin layer 92 contacts the side surface portion 11a of the housing 11.

[0043] The second resin layer 92 is in contact with the upper surface and outer side surface of the dam portion 40, the upper end portion of the upper surface 50A and the side surface of the metal member 50, the joint portion 80a and the curved portion 80b of the terminal board 80, and the lower end side portion of the wiring portion 80c. The second resin layer 92 is in contact with the outer surface of the dam portion 40, which is an uneven surface. As shown in FIG. 3, the second resin layer 92 fills a wedge-shaped space β between the bottom surface of the curved portion 82b and the upper surface 50A of the metal member 50.

[0044] As a result of the above, the upper surface 10A of the base plate 10, the substrate 20, the electrode plate 22, the semiconductor chip 30, the dam portion 40, the metal member 50, the wire 60, and the terminal plate 80 arranged in the internal space of the housing 11 are covered with the first resin layer 91 or the second resin layer 92, thereby ensuring insulation.

[0045] The elastic modulus of the second resin layer 92 is lower than that of the first resin layer 91. The elastic modulus of the dam portion 40 is higher than that of the second resin layer 92 and lower than that of the first resin layer 91. The thermal expansion coefficient of the second resin layer 92 is higher than that of the first resin layer 91.

[0046] The operation of the power module 100 according to this embodiment will be described below. In the power module 100, for example, power is supplied from the external connection terminal board 82, a signal is transmitted via the internal wiring terminal board 83, and a current controlled in the multiple semiconductor chips 30 is output to an external device from the external connection terminal board 81. Heat generated by this current flow is transmitted to the first resin layer 91 and the second resin layer 92 that fill the internal space of the housing 11, and to the substrate 20.

[0047] The thermal expansion coefficient of the first resin layer 91 is lower than that of the second resin layer 92, and the thermal expansion of the first resin layer 91 is smaller and more minute than that of the second resin layer 92. The elastic modulus of the first resin layer 91 is higher than that of the second resin layer 92, and the first resin layer 91 is less likely to be deformed by an external force. For this reason, the inner side of the dam portion 40, the upper surface 21A of the base 21, the upper surface and side of the electrode plate 22, the lower end of the side of the metal member 50, the upper surface and side of the semiconductor chip 30, the chip connection portion 61a and the electrode plate connection portion 61b of the wire 61, the electrode plate connection portion 62b and the curved portion 62c of the wire 62, and the electrode plate connection portion 63b of the wire 63 continue to be in contact with the first resin layer 91. In particular, the chip connection portion 61a and the electrode plate connection portions 62b, 63b hardened by bonding are fixed in the first resin layer 91, and fatigue failure due to thermal cycles is suppressed.

[0048] On the other hand, the volume of the second resin layer 92 changes depending on the temperature, the elastic modulus of the second resin layer 92 is lower than the elastic modulus of the first resin layer 91, and the second resin layer 92 is soft and fluid. Therefore, even if the temperature of the second resin layer 92 changes, the second resin layer 92 continues to be in contact with the upper surface of the first resin layer 91, the upper surface 10A of the base plate 10, the side surface portion 11a of the housing 11, and the side surface of the substrate 20.

[0049] 3, the second resin layer 92 does not peel off from the bottom surface of the curved portion 82b of the terminal board 82 disposed inside the second resin layer 92 and the top surface 50A of the metal member 50, and fills the wedge-shaped space β. This ensures the insulation between the terminal board 82 and the metal member 50.

[0050] Further, the second resin layer 92 encapsulates and continues to be in contact with the curved portion 61c of the wire 61 and the curved portion 63c of the wire 63. In particular, for the wire 63 which is longer than the other wires 61, 62 and whose length changes greatly due to temperature changes, the second resin layer 92 can continue to be in contact with the curved portion 63c while allowing the wire 63 to change in length due to temperature changes, thereby ensuring the insulation of the curved portion 63c.

[0051] In addition, the second resin layer 92 is also in contact with the outer surface of the dam portion 40. Since the first resin layer 91 formed to have the same height as the dam portion 40 or a height slightly lower than the height of the dam portion 40 is disposed inside the dam portion 40, deformation or destruction is suppressed even if stress is applied from the second resin layer 92.

[0052] The substrate 20 dissipates heat generated within the substrate unit U1 by transmitting it to the base plate 10 via the back electrode plate 23. On the other hand, the base plate 10 expands or contracts due to temperature changes, but since the back electrode plate 23 is soldered over most of the upper surface 10A of the base plate 10, the base plate 10 bends.

[0053] The substrates 20 bend in the same direction following the bending of the base plate 10, but since each substrate 20 is smaller than the base plate 10, the stress is alleviated. As a result, the first resin layer 91 provided on the substrate 20 is prevented from peeling off from the upper surface 20A of the substrate 20 and the inner surface of the dam portion 40, and the occurrence of cracks is suppressed.

[0054] In addition, the side surface of the first resin layer 91 is covered by the inner surface of the dam portion 40, which has a lower elastic modulus than that of the first resin layer 91, and is therefore less susceptible to stress from the second resin layer 92. In addition, the uneven surface formed on the inner surface of the dam portion 40, which has a lower elastic modulus than that of the first resin layer 91, and the uneven surface formed on the side surface of the first resin layer 91 are interlocked and in contact with each other, so that even if stress is applied from the second resin layer 92 and the substrate 20, peeling and destruction of the dam portion 40 and the first resin layer 91 are unlikely to occur.

[0055] In the power module 100, the four substrate units U1 are provided approximately evenly on the upper surface 10A of the base plate 10, so that the four substrate units U1 are less susceptible to the effect of bending of the base plate 10, further suppressing peeling and cracking of the first resin layer 91. In addition, the area of ​​each of the first resin layers 91 is also small, so that the first resin layers 91 are less likely to peel off due to bending. In addition, because the first resin layer 91 having a high elastic modulus is not in contact with the base plate 10, peeling of the first resin layer 91 due to bending of the base plate 10 is suppressed. On the other hand, the second resin layer 92 having a low elastic modulus is in contact at its lower part with the upper surface 10A of the base plate 10 and the side surface portion 11a of the housing 11, so it does not peel off even if the base plate 10 is bent.

[0056] A method for manufacturing the power module according to this embodiment will be described below. 5(a) to 6(b) are cross-sectional views showing a method for manufacturing a power module according to the embodiment.

[0057] First, a substrate 20 is prepared. As shown in FIG. 5(a), the back electrodes 32 of the multiple semiconductor chips 30 are, for example, soldered to predetermined locations on the electrode plate 22a of the substrate 20, the bottom surfaces of the multiple metal members 50 are, for example, soldered to predetermined locations on the electrode plate 22c of the substrate 20, and the back electrode plate 23 of the substrate 20 is fixed to the upper surface 10A of the base plate 10, for example by soldering.

[0058] As shown in FIG. 5(b), next, the dam portion 40 is formed by a dam agent, for example, a silicone adhesive. The dam agent preferably has good thixotropy. As shown in FIG. 1, one bulge 40a of the dam portion 40 is formed by applying the dam agent to the inner circumference of the edge of the upper surface 20A of the substrate 20, for example, three times, and then heating and curing the dam agent. As shown in FIG. 5(b), the process of applying and curing the dam agent is repeated three times to form the dam portion 40 having three bulges 40a and two constrictions 40b.

[0059] 6(a), next, a plurality of wires 61, 62, 63 are joined by, for example, ultrasonic bonding. One end of the wire 61 is joined to the electrode plate 22b, and the other end is joined to the upper surface electrode 31 of a predetermined semiconductor chip 30. Both ends of the wire 62 are joined to the electrode plates 22d and 22e, respectively. Both ends of the wire 63 are joined to the electrode plate 22c of the first substrate unit U11 and the electrode plate 22a of the second substrate unit U12, respectively.

[0060] 6(b), next, a first resin layer 91 is formed. The first resin layer 91 is formed by, for example, pouring a liquid resin containing epoxy onto the inside of the dam portion 40 to a height equal to or lower than the height of the dam portion 40, and then, for example, thermally curing the resin.

[0061] As shown in FIG. 4, the height H91 of the first resin layer 91 is lower than the height H50A of the upper surface 50A of the metal member 50, so that the cleanliness of the upper surface 50A of the metal member 50 is maintained. This improves the bonding between the joint 80a of the terminal board 80 and the upper surface 50A of the metal member 50, for example, by ultrasonic bonding. In addition, by raising the bonding portion of the terminal board 80 by the metal member 50, the first resin layer 91 can be formed before the bonding operation of the joint 80a of the terminal board 80. This allows the first resin layer 91 to be formed in a state in which the side portion 11a of the housing 11 and the multiple terminal boards 80 are not arranged, as shown in FIG. 6(b), and therefore improves workability.

[0062] 3, next, for example, an adhesive is applied onto the end portion of base plate 10, and side surface portion 11a is assembled. As a result, joints 82a, 83a of a plurality of external connection terminal boards 82 and internal wiring terminal boards 83 formed in advance on side surface portion 11a of housing 11 come into contact with predetermined locations of metal member 50. Next, external connection terminal board 81 is placed at a predetermined position on side surface portion 11a, and joint portion 81a of external connection terminal board 81 comes into contact with predetermined metal member 50. Joint portions 81a, 82a, 83a of terminal board 80 and corresponding metal member 50 are joined by, for example, ultrasonic joining.

[0063] Next, second resin layer 92 is placed in the internal space of housing 11, and the top surface of housing 11 is combined with side surface portion 11a. As a result, second resin layer 92 is sealed in housing 11, and external connection terminal board 81 is held between the top surface of housing 11 and side surface portion 11a.

[0064] In this embodiment, four board units U1 are provided, but the number of board units U1 may be one or more, and they are not limited to the same shape. In addition, when a plurality of board units U1 are provided, all of the board units U1 do not need to include the metal member 50. Specifically, if the terminal board 80 is not connected to one board unit U1, the metal member 50 does not need to be disposed.

[0065] Moreover, the metal member 50 is provided on the electrode plate 22c, but is not limited thereto. Specifically, the metal member 50 may be provided, for example, in an empty area on the other electrode plates 22a, 22b, 22d, and 22e within a range in which circuit wiring can be configured. The wire 63 connecting the two substrate units U1 is also not limited to this embodiment, and may be connected, for example, to an empty area on the other electrode plates 22b, 22d, and 22e within a range in which circuit wiring can be configured, or may be directly connected to an upper surface electrode (a second electrode in the claims) of another semiconductor chip (a second semiconductor chip in the claims).

[0066] In this embodiment, the dam portion 40 is provided on the upper surface 21A of the base 21, but is not limited thereto, and may be provided, for example, partially on the electrode plate 22, and the height H40 of the dam portion 40 may differ partially. The height H40 of the dam portion 40 may differ for each substrate unit U1, and specifically, the height of the dam portion 40 may be changed by changing the number of times or the speed at which the dam agent is dripped. The number of bulging portions 40a of the dam portion 40 is preferably two or more, and preferably two or three.

[0067] The dam portion 40 is formed in a closed fence shape on the inner periphery of the edge side of the substrate 20 when viewed from above, without any other configuration being interposed, but is not limited to this. For example, the dam portion 40 may be arranged along the edge side of the substrate 20, and formed in a closed fence shape with, for example, a metal member 50 or a resin piece being interposed on the inner periphery of the edge side. In addition, the dam portion 40 is not limited to being arranged along the edge side of the substrate 20, and may be arranged on the inside on the substrate 20.

[0068] The effects of the power module according to this embodiment will be described below. According to the power module of this embodiment, a substrate unit U1 having a substrate 20 is disposed on the upper surface 10A of a base plate 10, a fence-shaped dam portion 40 is provided on the inner periphery of the edge on the substrate 20, and a first resin layer 91 is formed inside the dam portion 40 on the upper surface 20A of the substrate 20. As a result, even if the base plate 10 is bent due to a temperature change, the first resin layer 91 is not in contact with the base plate 10 and is disposed on the substrate 20 where the bending is relaxed, so that peeling and cracking are suppressed and the insulating properties as a sealing material can be ensured. Furthermore, according to the power module 100 of this embodiment, a substrate unit U1 having an area smaller than that of the upper surface 10A of the base plate 10 is provided, so that each substrate 20 is less susceptible to the effects of bending of the base plate 10, which further suppresses peeling and cracking of the first resin layer 91, and ensures the insulation provided by the first resin layer 91.

[0069] Moreover, the first resin layer 91 encapsulates the chip connection portions 61a and the electrode plate connection portions 61b, 62b, and 63b of the wires 61, 62, and 63. Therefore, the chip connection portions 61a and the electrode plate connection portions 61b, 62b, and 63b that have been hardened by bonding are fixed in the first resin layer 91, which is difficult to deform, and thus destruction due to stress load is suppressed.

[0070] In this embodiment, the second resin layer 92 fills the internal space of the housing 11 and is provided on the first resin layer 91 and the substrate unit U1. As a result, the second resin layer 92, which has a low elastic modulus, contacts the upper surface 10A of the base plate 10, the side surface portion 11a of the housing 11, and the side surface of the substrate 20, and is not easily peeled off even when the base plate 10 is bent. In addition, the second resin layer 92 is not easily peeled off from the upper surface 50A and the upper end of the side surface of the metal member 50 and the terminal board 80, and can ensure insulation. In addition, the second resin layer 92 includes the curved portion 61c of the wire 61 and the curved portion 63c of the wire 63, and can ensure insulation of the curved portions 61c and 63c while allowing slight deformation of the wires 61 and 63 due to temperature changes.

[0071] Moreover, according to the power module 100 of this embodiment, the first resin layer 91 is formed inside the fence-shaped dam section 40. The height of the dam section 40 is made higher than the height of the chip connection section 61a, and the height of the first resin layer 91 is made higher than the height of the chip connection section 61a, and is equal to or lower than the height of the dam section 40 and lower than the height of the upper surface 50A of the metal member 50. As a result, the chip connection section 61a and the electrode plate connection sections 61b, 62b, and 63b are disposed inside the first resin layer, and the entire terminal board 80 is disposed inside the second resin layer 92, so that insulation can be ensured. In addition, the bonding between the upper surface 50A of the metal member 50 and the bonding section 80a can be improved, and the bonding work can be facilitated. In addition, by forming the first resin layer 91 inside the dam section 40, deformation and destruction of the dam section 40 are suppressed even when stress is applied from the second resin layer 92 and the substrate 20, and peeling and cracking of the first resin layer 91 can be suppressed.

[0072] As described above, according to the power module 100 of this embodiment, even in operating conditions in which there is a large temperature change due to current flow, it is possible to ensure insulation while preventing damage to the internal configuration, thereby improving reliability.

[0073] In the case where the first resin layer 91 is not disposed inside the dam portion 40 provided on the substrate 20 as in the power module 100 of this embodiment, for example, the first resin layer contacts the substrate at the center side of the bottom surface, but contacts the base plate and the side surface of the housing at the edge side of the bottom surface. In this case, since the first resin layer contacts the base plate and the side surface of the housing at the edge side where the displacement amount due to bending of the base plate is large, the edge portion is likely to peel off from the base plate and the side surface of the housing, and cracks are likely to occur. In addition, since the first resin layer occupies most of the upper surface of the base plate and has a large area, the edge side is more likely to peel off and cracks are likely to occur. In contrast, according to the power module of this embodiment, even in an operating condition where the temperature change due to current flow is large, it is possible to ensure insulation while suppressing damage to the internal configuration, and to improve reliability.

[0074] According to the embodiment described above, a highly reliable power module can be realized.

[0075] The above describes the embodiments of the present invention with reference to specific examples. However, the embodiments of the present invention are not limited to these specific examples. For example, the specific configurations of the shape, material, and arrangement of the electrode plate, metal member, terminal plate, semiconductor chip, dam portion, and first resin layer included in the power module are included in the scope of the present invention as long as a person skilled in the art can implement the present invention in the same way and obtain the same effect by appropriately selecting them from the known range. In particular, the material of the electrode plate, terminal plate, and wire is not limited to copper or aluminum, but may be other metals, or may be different metals from each other. In addition, a combination of two or more elements of each specific example within a technically possible range is also included in the scope of the present invention as long as it includes the gist of the present invention.

[0076] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0077] 10…Base plate 10A…Top surface 11…Housing 11a…Side part 20...Substrate 20A…Top surface 21...Base 21A…Top surface 22, 22a, 22b, 22c, 22d, 22e...electrode plate 23…Back electrode plate 30...Semiconductor chip 31…Top electrode 32…Back electrode 40…Dam section 40a...bulge 40b…Constricted part 50...Metal parts 50A…Top surface 60, 61, 62, 63…Wire 61a…Chip connection part 61b, 62b, 63b...Electrode plate connection parts 61c, 62c, 63c…Bends 80...Terminal board 80a, 81a, 82a, 83a...Joint part 80b, 82b...curved portion 80c, 82c...Wiring section 81, 82...External connection terminal board 82d…Drawer section 83...Terminal board for internal wiring 91...First resin layer 92…Second resin layer 100…Power module H40, H50A, H61a~H61c, H62c, H63c, H91...Height U1... Circuit board unit U11…First board unit U12: Second board unit X, Y, Z…direction β…Space

Claims

1. A base plate and A housing provided on the base plate; is disposed on the base plate, A substrate fixed on the base plate and having a plurality of electrode plates including at least a first and a second electrode plate on an upper surface thereof; a dam portion provided on the substrate and formed along an edge of the substrate when viewed from above; a first semiconductor chip provided on the first electrode plate and having a first electrode; A metal member provided on any one of the electrode plates; a first wire including an electrode plate connection portion connected to the second electrode plate, a chip connection portion connected to the first electrode, and a first curved portion located between the electrode plate connection portion and the chip connection portion; At least one substrate unit having a terminal board having a joint portion parallel to an upper surface of the metal member and a bottom surface of the joint portion joined to the upper surface of the metal member to form a joint surface, a second curved portion connected to the joint portion and curved upward from a direction parallel to the upper surface of the metal member, a wiring portion extending upward from the second curved portion, and a lead portion led from the wiring portion to the outside of the housing and a portion of which is located on the upper surface of the housing; a first resin layer provided on the substrate inside the dam portion, the first resin layer having the chip connection portion and the electrode plate connection portion disposed therein; a second resin layer provided on the first resin layer and the dam portion, the second resin layer having an elastic modulus lower than that of the first resin layer, the second resin layer having an upper surface of the metal member disposed therein; With The second resin layer fills a wedge-shaped space between a bottom surface of the second curved portion and an upper surface of the metal member.

2. The housing has a side surface, The power module according to claim 1 , wherein the second resin layer is in contact with the base plate in a gap between the substrate unit and the side surface portion.

3. a height of the dam portion from the upper surface of the substrate is greater than a height of the chip connection portion from the upper surface of the substrate; 3. The power module according to claim 1, wherein a height of the first resin layer from the upper surface of the substrate is equal to or less than a height of the dam portion, is higher than a height of the chip connection portion, and is lower than a height of the upper surface of the metal member from the upper surface of the substrate.

4. 4. The power module according to claim 1, wherein the dam portion has a modulus of elasticity higher than that of the second resin layer and lower than that of the first resin layer.

5. 5. The power module according to claim 1, wherein the dam portion includes a silicone resin and has at least two bulging portions and one constricted portion.

6. The power module according to any one of claims 1 to 5, wherein the first curved portion is disposed inside the second resin layer.

7. 7. The power module according to claim 1, wherein the first resin layer has a lower thermal expansion coefficient than the second resin layer.

8. The power module according to any one of claims 1 to 7, wherein the first resin layer contains an epoxy resin.

9. The power module according to any one of claims 1 to 8, wherein the second resin layer is in a gel state.

10. The device includes two of the substrate units, the one board unit and the other board unit are provided on the base plate and spaced apart from each other, The power module according to any one of claims 1 to 9, wherein the second resin layer is in contact with the base plate in the gap between the two substrate units.

11. Further comprising a second wire; the one substrate unit and the other substrate unit further include a second semiconductor chip provided on the electrode plate and having a second electrode; one end of the second wire is connected to the electrode plate or the second electrode of the one substrate unit, and the other end is connected to the electrode plate or the second electrode of the other substrate unit; The power module according to claim 10 , wherein an intermediate portion of the second wire is disposed in the second resin layer.

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