Molded power module and power module assembly

Abstract

A molded power module (2) comprises: - a substrate (12) comprising an upper conductive layer (5, 6); - at least one semiconductor (10, 10') on the upper conductive layer (5, 6) of the substrate (12); - a molded portion (30) covering the at least one semiconductor (10). The molded portion (30) comprises at least two hump portions (18, 18', 18") protruding from the remaining area of the molded portion (30), wherein the hump portions (18, 18', 18") are spaced apart from each other.

Description

Technical Field

[0001] This invention relates to a molded power module, which includes a substrate having an upper conductive layer, and at least one semiconductor located on the upper conductive layer. The invention also relates to a power module assembly. Background Technology

[0002] Molded modules, such as power modules, are widely used. When power modules are assembled onto heat sinks using thermal interface materials (TIMs) or adhesives, the thickness of the TIM or adhesive layer often becomes very thick in certain areas because the bottom surface of the power module is not smooth and includes small indentations. Since the available thermal interface materials and adhesives are not as good at thermal conductivity as the materials used to manufacture the bottom surface of the power module and / or heat sink, this localized thickening of the thermal interface material or adhesive can significantly reduce cooling efficiency, thereby reducing the efficiency of the power module itself.

[0003] TIM or adhesive is a paste-like material that is repeatedly heated and cooled during the use of the molded module. The volume of the molded module's components will change slightly in response to temperature fluctuations. Therefore, alternating thermal expansion and contraction, as well as the forces applied to the module, will gradually "pull out" some of the TIM or adhesive. Since the presence of TIM or adhesive is crucial for transferring heat from the power module to the heat sink, its loss during use would be a significant drawback.

[0004] Therefore, there is a need for a molded power module that reduces or even eliminates the aforementioned drawbacks of the prior art. Summary of the Invention

[0005] The objectives of this invention can be achieved through molded power modules and power module assemblies as provided in this invention.

[0006] The molded power module according to the present invention is a molded power module comprising:

[0007] - A substrate, the substrate including an upper conductive layer;

[0008] - At least one semiconductor, said at least one semiconductor being located on the upper conductive layer of the substrate;

[0009] - A molding portion covering the at least one semiconductor, wherein the molding portion includes at least two protrusions extending from the remaining area of ​​the molding portion, wherein the protrusions are spaced apart from each other.

[0010] Therefore, a molded power module can be provided that reduces or even eliminates the aforementioned disadvantages of the prior art. The stiffness of the molded power module can be reduced, thereby reducing internal stress within the module. This invention allows for a reduction in the thickness of the molded portion of the molded power module and / or provides the molded portion only above the semiconductor(s). The gaps between the protrusions reduce the overall mechanical stress within the molded power module and provide mechanical flexibility to the module. Therefore, the force required to provide sufficient thermal contact to the structure below the upper conductive layer (e.g., a heat sink) can be reduced.

[0011] The upper conductive layer may be a metal layer. In one embodiment, the upper conductive layer is made of copper. In another embodiment, the upper conductive layer is made of aluminum.

[0012] The upper conductive layer can be formed by a lead frame structure.

[0013] In one embodiment, a single semiconductor is located on the upper conductive layer of the substrate.

[0014] In one embodiment, two or more semiconductors are located on the upper conductive layer of the substrate.

[0015] The molded power module includes a molded portion covering at least one semiconductor. The molded portion is made of a non-conductive material. In one embodiment, the molded portion includes a molding compound, a polymer, an epoxy resin, or cement. In another embodiment, the molded portion is made of a molding compound, a polymer, an epoxy resin, or cement.

[0016] The molded portion includes at least two raised mounds protruding from the remaining area of ​​the molded portion, wherein the raised mounds are spaced apart from each other.

[0017] In one embodiment, the molded portion includes two raised mounds protruding from the remaining area of ​​the molded portion, wherein the raised mounds are spaced apart from each other.

[0018] In one embodiment, the molded portion includes three raised mounds protruding from the remaining area of ​​the molded portion, wherein the raised mounds are spaced apart from each other.

[0019] In one embodiment, the molded portion includes four raised mounds protruding from the remaining area of ​​the molded portion, wherein the raised mounds are spaced apart from each other.

[0020] In one embodiment, the molded portion includes five or more protrusions extending from the remaining area of ​​the molded portion, wherein the protrusions are spaced apart from each other.

[0021] In one embodiment, the protrusions are arranged over one or more semiconductors. Therefore, the protrusions allow for the application of large forces during manufacturing processes (e.g., during sintering or soldering processes, when the substrate is fixed to a heat sink) or during use (e.g., when pressing a module onto a heat sink, reducing the TIM layer to an extremely thin layer).

[0022] In one embodiment, the width of the protrusion corresponds to the width of the semiconductor disposed below the protrusion.

[0023] In one embodiment, the width of the protrusion is equal to or greater than the width of the semiconductor disposed below the protrusion.

[0024] In one embodiment, the width of the protrusion is greater than the width of the semiconductor disposed below the protrusion.

[0025] In one embodiment, the minimum width of the protrusion corresponds to the width of the semiconductor disposed below the protrusion.

[0026] In one embodiment, the minimum width of the protrusion is equal to or greater than the width of the semiconductor disposed below the protrusion.

[0027] In one embodiment, the minimum width of the protrusion is greater than the width of the semiconductor disposed below the protrusion.

[0028] In one embodiment, at least some of the protrusions are symmetrical.

[0029] In one embodiment, the protrusions are symmetrical.

[0030] In one embodiment, the central portion of the protrusion is disposed below the central portion of the semiconductor, which is disposed below the protrusion.

[0031] In one embodiment, the molded power module further includes one or more terminals electrically connected to and protruding from the upper conductive layer.

[0032] In one embodiment, the molded power module includes a single terminal electrically connected to and protruding from the upper conductive layer.

[0033] In one embodiment, the molded power module includes two terminals electrically connected to and protruding from the upper conductive layer.

[0034] In one embodiment, the molded power module includes three terminals electrically connected to and protruding from the upper conductive layer.

[0035] In one embodiment, the molded power module includes three or more terminals electrically connected to and protruding from the upper conductive layer.

[0036] In one embodiment, the protrusion extends above the horizontal plane of one or more terminals.

[0037] Therefore, raised dotted portions can be used to cover the proximal portions of one or more terminals. Thus, force can be applied to the raised dotted portions(s) covering the proximal portions of one or more terminals. The force is transmitted to the upper conductive layer through the raised dotted portions and the mold material of the one or more terminals.

[0038] In one embodiment, the substrate includes an insulator, wherein the upper conductive layer is located on the insulator.

[0039] In one embodiment, the substrate includes a lower conductive layer disposed beneath an insulator, wherein the insulator is sandwiched between an upper conductive layer and a lower conductive layer.

[0040] In one embodiment, the substrate is a direct copper bond (DCB) substrate.

[0041] In one embodiment, an intermediate region with mold material is provided between adjacent protrusions.

[0042] In one embodiment, an intermediate region made of a material other than the molded portion is provided between adjacent protrusions.

[0043] In one embodiment, an intermediate region (a gap without material) is provided between adjacent protrusions.

[0044] In one embodiment, only when the substrate extends fully between adjacent protrusions does it connect the adjacent protrusions. Therefore, the mechanical flexibility of the molded power module can be improved. Consequently, the overall mechanical stress within the molded power module can be reduced.

[0045] In one embodiment, the insulator extends fully between adjacent mounds to connect adjacent mounds.

[0046] In one embodiment, the substrate exposed on the surface of the molded power module includes several separated portions, each of which is at least partially surrounded by a cavity constituting a storage space for thermally conductive material. The surface is typically the bottom portion of the molded part.

[0047] In one embodiment, the substrate exposed on the surface of the module is a lower conductive layer.

[0048] The lower conductive layer may be a metal layer. In one embodiment, the lower conductive layer is made of copper. In another embodiment, the lower conductive layer is made of aluminum.

[0049] In one embodiment, the cavity is in fluid communication with a storage structure that at least partially surrounds the cavity, wherein the storage structure is configured to receive thermally conductive material from the cavity and return the thermally conductive material to the cavity. Therefore, the thermally conductive material does not escape into the surrounding environment as in the prior art.

[0050] In one embodiment, each separate portion is located directly below the protruding dome.

[0051] In one embodiment, only the separation portion is made of metal.

[0052] In one embodiment, only the separation section is made of copper.

[0053] In one embodiment, at least some cavities are formed into cavities in the molded portion.

[0054] In one embodiment, all cavities are configured as cavities within the molded portion.

[0055] In one embodiment, at least some of the storage structures are made into the storage structures in the molded portion.

[0056] In one embodiment, all storage structures are fabricated as storage structures within a molded portion.

[0057] In one embodiment, the molded portion surrounds the entire substrate, except for a separate portion protruding from the back side of the substrate through the molded portion.

[0058] In one embodiment, the molding portion covers the top side of the molding power module, wherein the back side of the substrate is not covered by the molding portion.

[0059] In one embodiment, the groove forming the cavity is etched into the back side of the substrate.

[0060] In one embodiment, the grooves forming the storage structure are etched into the back side of the substrate.

[0061] In one embodiment, the thickness of the insulator is in the range of 0.1-0.8 mm.

[0062] In one embodiment, the thickness of the conductive layer is in the range of 0.1-3.0 mm.

[0063] In one embodiment, the thickness of the thermally conductive material is in the range of 0.005-1.0 mm.

[0064] In one embodiment, the thermally conductive material is a sintered body with a thickness of less than 500 µm, preferably less than 100 µm.

[0065] In one embodiment, the thermally conductive material is a thermal interface material with a thickness of less than 50 µm, preferably a thermal interface material in the range of 5-50 µm.

[0066] In one embodiment, the mound includes a flat top portion and an inclined portion extending therefrom.

[0067] In one embodiment, the angle α between the top portion and the inclined portion is in the range of 30-89 degrees.

[0068] In one embodiment, the angle α between the top portion and the inclined portion is in the range of 40-88 degrees.

[0069] In one embodiment, the angle α between the top portion and the inclined portion is in the range of 45-88 degrees.

[0070] Molded power modules can be advantageously combined with heat sinks or substrates to form power module assemblies.

[0071] In one embodiment of this power module assembly, a heat sink or substrate is disposed beneath and thermally connected to the substrate. Therefore, the heat sink or substrate can be used to provide effective cooling of the heat generated by the molded power module.

[0072] In one embodiment, a thermally conductive material is provided between the heat sink or substrate and the substrate.

[0073] In one embodiment, the power module assembly includes a structure arranged and configured to press a molded power module against a heat sink or substrate by applying pressure to the protrusions. Therefore, compared to the prior art, the overall force can be reduced because, in this invention, pressure is applied only in the areas where pressure is required (above the semiconductors).

[0074] In one embodiment, the power module assembly includes a fixing device configured to provide force downward toward the substrate at the top of the protrusion.

[0075] In one embodiment, the fixing device is attached to the heat sink or substrate by screws.

[0076] In one embodiment, the fixing device includes one or more spring washers.

[0077] In one embodiment, the fixing device includes one or more screws.

[0078] In one embodiment, the fixing device is a cover for the housing.

[0079] In one embodiment, the mounting device is a cover for the inverter housing.

[0080] In one embodiment, the fixing device includes a plate arranged and configured to provide force to the top surface of the protrusion.

[0081] In one embodiment, the fixing device includes a clamping structure arranged and configured to provide a force of at least 1 N to each protrusion.

[0082] In one embodiment, at least some of the cavities are formed in the upper surface of a heat sink.

[0083] In one embodiment, all cavities are formed in the upper surface of the radiator.

[0084] In one embodiment, at least some of the above-described storage structures are made into storage structures on the upper surface of a heat sink.

[0085] In one embodiment, all storage structures are fabricated as storage structures on the upper surface of a heat sink. Attached Figure Description

[0086] The invention will be more fully understood from the detailed description given below. The accompanying drawings are given by way of illustration only and are therefore not intended to limit the invention. In the drawings:

[0087] Figure 1A A side view of the molded power module according to the present invention is shown;

[0088] Figure 1B It shows including Figure 1A A side view of the power module assembly of the molded power module shown;

[0089] Figure 1C It shows Figure 1B The side view of the power module assembly shown includes a fixing device arranged and configured to provide force to the top surface of the molded power module portion.

[0090] Figure 2A A cross-sectional view of a molded power module according to the present invention is shown;

[0091] Figure 2B A cross-sectional view of another molded power module according to the present invention is shown;

[0092] Figure 2C A cross-sectional view of a power module assembly according to the present invention is shown;

[0093] Figure 3A An exploded view of a power module assembly including a molded power module according to the present invention is shown;

[0094] Figure 3B It shows Figure 3A The diagram shows a cross-sectional view of the power module assembly in a configuration where a molded power module is attached to a heat sink.

[0095] Figure 4A A cross-sectional view of a molded power module according to the present invention is shown;

[0096] Figure 4BA cross-sectional view of another molded power module according to the present invention is shown;

[0097] Figure 5A A perspective top view of the molded power module according to the present invention is shown;

[0098] Figure 5B It shows Figure 5A The perspective bottom view of the molded power module shown;

[0099] Figure 5C It shows Figure 5A and Figure 5B A cross-sectional view of the molded power module shown;

[0100] Figure 6A A cross-sectional view of a power module assembly according to the present invention is shown;

[0101] Figure 6B It shows Figure 6A A close-up view of a portion of the power module assembly shown;

[0102] Figure 6C A molded power module of the prior art is shown.

[0103] Figure 7 It shows the relationship with Figure 1C A side view of a similar power module assembly;

[0104] Figure 8 A side view of a specific embodiment of the power module assembly of the present invention is shown;

[0105] Figure 9 Detailed cross-sectional views of the cavity and storage structure used to control the movement and distribution of the thermally conductive material are shown;

[0106] Figure 10 A partial cross-sectional view of an embodiment of the molded power module according to the present invention is shown, and

[0107] Figure 11 A partial cross-section of another embodiment of the power module of the present invention is shown. Detailed Implementation

[0108] Preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings. Figure 1A The molded power module 2 of the present invention is shown in the figure.

[0109] Figure 1A A side view of a molded power module 2 according to the present invention is shown. The molded power module 2 includes a lower box-shaped portion on which two spaced-apart protrusions 18, 18' are located.

[0110] The height (thickness) of the lower box-shaped section basically corresponds to the height (thickness) of the convex mounds 18 and 18'.

[0111] The lower box-shaped portion includes a first base structure 26 and a second base structure 26'. The first base structure 26 forms a first end portion, while the second base structure 26' forms a second opposing end portion. An intermediate region 24 is provided between the protruding mounds 18 and 18'. The space between the protruding mounds 18 and 18' substantially corresponds to the width of the second protruding mound 18'. Each protruding mound 18 and 18' is an isosceles trapezoid.

[0112] Figure 1B It shows including Figure 1A The diagram shows a side view of the power module assembly 3 of the molded power module 2. The molded power module 2 is located on an interface 13 on the heat sink 20. The interface 13 includes a thermally conductive material to conduct heat generated within the molded power module 2 to the heat sink 20. The interface may include a material suitable for enhancing thermal contact between the molded power module 2 and the heat sink 20. Such material may include thermal interface materials, grease, or fluids. The interface may optionally or additionally include a material for maintaining fixed contact between the molded power module 2 and the heat sink 20. Such material may include a sintered layer, a solder layer, or an adhesive layer.

[0113] Figure 1C It shows Figure 1B The side view of the power module assembly 3 shown includes a fixing device 28 arranged and configured to provide force to the top surface of the molded power module 2. The fixing device 28 is shaped like a plate with through holes. Screws 31, 31' extend through these through holes. The screws 31, 31' are attached to a heat sink 20. Thus, the fixing device 28 presses the molded power module 2 against the heat sink 20. In one embodiment, the screws 31, 31' are screwed into corresponding threaded holes in the heat sink 20.

[0114] Figure 2A A cross-sectional view of a molded power module 2 according to the present invention is shown. The molded power module 2 includes a lead frame structure 11 having three separate upper conductive layers 5, 5', 5''. A first semiconductor 10 is located on the first upper conductive layer 5. A second semiconductor 10' is located on the third upper conductive layer 5''. Wire bonding 22 electrically connects the first semiconductor 10 and the second upper conductive layer 5'.

[0115] The molded power module 2 includes a molding portion 30, which substantially corresponds to a reference. Figure 1A The molded portion shown and explained. The molded portion 30 includes a lower box-shaped portion and two spaced-apart protrusions 18, 18' protruding from the box-shaped portion.

[0116] The height of the box-shaped portion corresponds to the height of the raised portions 18 and 18'. The lower box-shaped portion includes a first base structure 26 and a second base structure 26', as well as an intermediate region 24 disposed between the raised portions 18 and 18'. The raised portions 18 and 18' extend from the remaining area of ​​the molded portion 30.

[0117] Figure 2B A cross-sectional view of another molded power module 2 according to the present invention is shown. The molded power module 2 includes a molded portion 30, which includes components related to... Figure 2A As shown and referenced Figure 2A The explanation is the same as the structure.

[0118] The molded power module 2 includes a substrate 12, which has three separate upper conductive layers 6, 6', and 6'' located on an insulator 4. The insulator 4 is located on a first lower conductive layer 8 and a second lower conductive layer 8'. The lower conductive layers 8 and 8' are respectively disposed below the first semiconductor 10 and the second semiconductor 10'. The substrate 12 may be a DCB substrate.

[0119] The first semiconductor 10 is located on the first upper conductive layer 6, while the second semiconductor 10' is located on the third upper conductive layer 6". Wire bonding 22 electrically connects the first semiconductor 10 and the second upper conductive layer 6'.

[0120] The protruding mounds 18 and 18' include inclined side portions 32 and 32'. Angle α is indicated for the left side portion of the first protruding mound 18. Angle α (between the top portion 50 and the inclined side portion 32) is approximately 45 degrees. However, angle α can be smaller, for example, in the range of 5-40 degrees.

[0121] Figure 2C A cross-sectional view of a power module assembly 3 according to the present invention is shown. The power module assembly 3 includes a molded power module 2, characterized by... Figure 2B As shown and referenced Figure 2B The explained features are the same. However, the power module assembly 3 includes a heat sink 20. A first lower conductive layer 8 and a second lower conductive layer 8' of the substrate 12 are located on and attached to the heat sink 20. Therefore, a thermal connection is established between the lower conductive layers 8, 8' and the heat sink 20. Thus, the heat generated by the first semiconductor 10 and the second semiconductor 10' can be transferred to the heat sink 20. The heat sink 20 can release the generated heat to the surrounding environment through heat exchange.

[0122] Figure 3A An exploded view of a power module assembly 3 including a molded power module 2 according to the present invention is shown. The molded power module 2 substantially corresponds to... Figure 2A As shown and referenced Figure 2AExplanation of the power module. The molded power module 2 is positioned above the insulator 4. The insulator 4 is positioned above the heat sink 20.

[0123] Figure 3B It shows Figure 3A The diagram shows a cross-sectional view of the power module assembly 3, in which the molded power module 2 is attached to the heat sink 20. A force F is applied to the protrusions 18, 18' in such a way that the molded power module 2 is pressed against the heat sink 20.

[0124] Figure 4A A cross-sectional view of a molded power module 2 according to the present invention is shown. The molded power module 2 includes a DCB substrate 12 having an insulator 4 sandwiched between upper conductive layers 6, 6', 6” and lower conductive layers 8, 8'. A first semiconductor 10 is attached to a first upper conductive layer 6. A second semiconductor 10' is attached to a third upper conductive layer 6”. Wire bonding 22 electrically connects the first semiconductor 10 and the second upper conductive layer 6'.

[0125] The molded power module 2 includes a molded portion 30, which includes two spaced-apart protrusions 18, 18'.

[0126] The first protrusion 18 extends from the first base structure 26 of the molding portion 30. Similarly, the second protrusion 18' extends from the second base structure 26'. An intermediate region 24 is provided between the protrusions 18 and 18'. It can be seen that the intermediate region 24 is empty and therefore does not contain molding compound. A blank space is also provided below the insulator 4 below the intermediate region 24.

[0127] Figure 4B An exploded view of another molded power module 2 according to the present invention is shown. The molded power module 2 substantially corresponds to... Figure 4A As shown and referenced Figure 4A The molded power module is explained. However, material 34 is set in the intermediate region 24. Therefore, the intermediate region 24 is not like... Figure 4A The middle area is empty. Similarly, material 34 is also placed below the insulator 4 below the middle area 24.

[0128] Figure 5A A perspective top view of the molded power module 2 according to the present invention is shown. Figure 5B It shows Figure 5A The above is a perspective bottom view of the molded power module 2. Figure 5C It shows Figure 5A and Figure 5B The cross-sectional view of the molded power module 2 shown.

[0129] The molded power module 2 includes a molded portion having a plurality of protrusions 18, 18' projecting from the rest of the molded portion. The protrusions 18, 18' are located at the top side 36 of the module 2. The protrusions 18, 18' are of equal shape and spaced apart. The protrusions 18, 18' are arranged in two parts, separated by a space disposed above the central portion of the molded power module 2.

[0130] The molded power module 2 includes multiple terminals 14, 15, 16, and 17. Three terminals 14, 15, and 16 protrude from a first end portion of the molded power module 2. A single terminal 17 extends from an opposite end of the molded power module 2. Terminals 14, 15, 16, and 17 extend parallel to each other.

[0131] Terminals 14, 15, 16, and 17 extend through the base structure 26 of the molded portion.

[0132] Figure 5B A plurality of substrate portions 40, 40' are shown disposed at the bottom side 38 of the molded power module 2. Each portion 40, 40' is arranged below the raised portions 18, 18'. A gap 41 may at least partially surround each portion 40, 40'. In this embodiment, the gap 41 is formed as a trench completely surrounding the respective substrate portion. These gaps 41 can advantageously be used as cavities 44 and / or storage structures 48 as described below.

[0133] Figure 5C The molded power module 2 is shown to include a substrate having an upper conductive layer 6, wherein a plurality of semiconductors 10, 10', 10" are located on the upper conductive layer 6. It can be seen that the molded power module 2 includes a plurality of terminals 14, 17 electrically connected to and protruding from the upper conductive layer 6. The molded power module 2 includes molded portions covering the semiconductors 10, 10', 10" . The protrusions 18, 18' include inclined portions 32, 32' and flat-topped portions. The protrusions 18, 18' are spaced apart from each other, and a central region 24 extends between them.

[0134] Figure 6A A cross-sectional view of a power module assembly 3 according to the present invention is shown. The power module assembly 3 includes a substrate 12 having an insulator 4 sandwiched between an upper conductive layer 6 and a lower conductive layer 8. Semiconductors 10 and 10' are located on the upper conductive layer 6. Wire bonding 22 is used to electrically connect the semiconductors 10 and 10' to the upper conductive layer.

[0135] The power module assembly 3 includes terminals 17 electrically connected to and protruding from the upper conductive layer 6. The power module assembly 3 includes molded portions covering semiconductors 10, 10'.

[0136] The molded portion includes a plurality of raised mounds 18, 18', 18" protruding from the remaining area of ​​the molded portion. The raised mounds 18, 18', 18" are spaced apart from each other. An intermediate region 24 is provided between adjacent raised mounds 18, 18', 18".

[0137] The lower conductive layer 8 is attached to the heat sink 20. A thermally conductive material 42 (e.g., a thermal interface material, grease, fluid, or sintered material) is disposed between the lower conductive layer 8 and the heat sink 20 to improve thermal bonding. A force F is applied from above to the protrusions 18, 18', 18".

[0138] Figure 6B It shows Figure 6A A close-up view of a portion of the power module assembly 3 is shown. It can be seen that cavities 44 are disposed adjacent to portions 40, 40' of the lower conductive layer 8. Each cavity 44 serves as a storage space for the thermally conductive material 42. In this embodiment, the cavities 44 surround each "metal island" portion 40, 40' of the lower conductive layer 8. Each portion 40, 40' is surrounded by a larger cavity 44, which is in turn surrounded by two smaller storage structures 48, formed here as recesses. The storage structures 48 act as reservoirs in which excess TIM (or adhesive) can flow when the module is pressed into the heat sink 20 with force F. This allows the TIM layer to be as thin as possible (limited only by the surface roughness of the module and the heat sink) without localized thickening that would otherwise significantly increase thermal resistance.

[0139] The substrate 12 exposed at the surface of the power module assembly 3 includes a plurality of separated portions 40, 40', each of which is at least partially surrounded by a cavity 44 constituting a storage space for thermally conductive material. Thus, during alternating thermal expansion and contraction and when force is applied to the power module assembly 3, the thermally conductive material 42 can enter and exit the cavity 44.

[0140] As can be seen, the filling material 46 is disposed in the space between adjacent lower conductive layers 8. Furthermore, a storage structure 48 is disposed next to the cavity 44. The storage structure 48 can constitute a guiding structure or a barrier.

[0141] Figure 6C A prior art power module assembly 102 is shown. The power module assembly 102 includes a DCB substrate 112 having an insulator 104 sandwiched between an upper conductive layer 106 and a lower conductive layer 108. Semiconductors 110, 110' are located on the upper conductive layer 106. The DCB substrate 112 is attached to a heat sink 20. The power module assembly 102 includes a molded portion having a generally box-shaped geometry. Wire bonding 122 is used for electrically connecting the semiconductor 110 and the upper conductive layer.

[0142] Figure 7 It shows the relationship with Figure 1CThe power module assembly shown is a side view of a similar power module assembly. Here, the power module assembly 3 includes a fixing device 28 arranged and configured to provide force to the top surface of the molded power module 2. The fixing device 28 is shaped like a plate with through holes. Screws 31, 31' pass through these through holes. The screws 31, 31' are attached to the heat sink 20. Thus, the fixing device 28 presses the molded power module 2 against the heat sink 20. In one embodiment, the screws 31, 31' are screwed into corresponding threaded holes in the heat sink 20. Figure 1C In contrast to the embodiment shown, springs 62, 62' are inserted between the plate and the module to further stabilize the downward force applied to the module on top of the protrusions 18, 18'.

[0143] exist Figure 7 In the illustrated embodiment, thermally conductive material 42 is shown located between the base of power module 2 and heat sink 20. In this case, the thermally conductive material includes a fluid (such as thermally conductive grease) or other material that can flow when pressure is applied to the top of the module. Applying pressure to the top of the module via the protrusions 18, 18' causes an increase in pressure directly below the protrusions 18, 18', resulting in a thinner film of thermally conductive material. Therefore, in the area marked 64, the thermally conductive material is much thinner than in other areas. This thinning of the thermally conductive material will preferentially occur in the area directly below the protrusions, thus directly below the heat-generating components within the power module.

[0144] Figure 8 A side view of a specific embodiment of the power module assembly 3 of the present invention is shown. Here, a membrane 61, such as an organic membrane, is placed between the power module 2 and the heat sink 20, and pressure and heat are applied to permanently laminate the power module 2 and the heat sink 20 together to form a single power module assembly structure 3. As described above, during the lamination process, the combination of the pressure applied to the tops of the protrusions 18, 18' and the fluidity of the material 43 results in a significant thinning of the thermally conductive material region 64 at the structural critical point.

[0145] Figure 9 A detailed cross-sectional view is shown of the cavity 44 and the storage structure 48 used to control the movement and distribution of the thermally conductive material 42. The cavity 44 and the storage structure 48 are formed here within the encapsulation molding material 30 at the same level as the lower conductive layer 8 of the substrate 12. A portion of the thermally conductive material 42 is shown as partially filling the cavity 44 and the storage structure 48.

[0146] Figure 10 A partial cross-sectional view of an embodiment of the molding power module 2 according to the present invention is shown. The structure of the molding power module 2 in this embodiment is similar to... Figure 2C The structure shown includes a molded portion 30, which includes components related to... Figure 2A As shown and referenced Figure 2A The structure explained is the same. Power module 2 is shown combined with heat sink 20 to form power module assembly 3. This establishes a thermal connection between the lower conductive layer 8 and heat sink 20. Therefore, heat generated by semiconductor 10 can be transferred to heat sink 20. Heat sink 20 can release the generated heat to the surrounding environment through heat exchange. In this embodiment, cavity 44 and storage structure 48 are again used to control the movement and distribution of thermally conductive material 42. Cavity 44 and storage structure 48 are formed here within the upper surface of heat sink 20. A portion of the thermally conductive material 42 is shown partially filling cavity 44 and storage structure 48.

[0147] Figure 11 A partial cross-section of another embodiment of the power module 2 of the present invention is shown. Here, a cavity 44 for storing thermally conductive material 42 (not shown) is formed by an etched structure in the lower conductive layer 8. Material has been removed from the lower conductive layer 8 to form a gap that forms the cavity 44 for storing the thermally conductive material.

[0148] List of reference numerals

[0149] 2 Molded power modules

[0150] 3 Power Module Components

[0151] 4. Insulators

[0152] 5', 5" upper conductive layer of the lead frame

[0153] 6, 6', 6” conductive layer

[0154] 8, 8' Lower conductive layer

[0155] 10 Semiconductors

[0156] 11. Lead Frame Structure

[0157] 12 Substrates

[0158] 13 Interfaces

[0159] 14, 15 terminals

[0160] 16, 17 terminals

[0161] 18, 18', 18” convex mound

[0162] 20 Heat sink or base plate

[0163] 22-lead wire bonding

[0164] 24. Middle Area

[0165] 26, 26' base structure

[0166] 28 Fixture

[0167] 30. Molded parts (molding material)

[0168] 31, 31' screws

[0169] 32' and 32' inclined sections

[0170] 34 Materials

[0171] 36 Top side

[0172] 38 Bottom side

[0173] 40', 40' Substrate Cross-section / Separation Section

[0174] 41 gap

[0175] 42 Thermally conductive materials (e.g., thermal interface materials, greases, fluids, or sintered materials)

[0176] 44. Cavity (storage space for thermally conductive material)

[0177] 46. ​​Filler material

[0178] 48 Storage Structure

[0179] 50 Top section

[0180] 61-Laminated Film

[0181] 62' springs

[0182] 63. Forces applied during lamination

[0183] 64 Thin thermally conductive material area

[0184] F force

[0185] α angle

[0186] 102 Power Module Assembly

[0187] 104 Insulator

[0188] 106 Upper conductive layer

[0189] 108 Lower conductive layer

[0190] 110 Semiconductors

[0191] 110' Semiconductor

[0192] 112 substrate

[0193] 122 Wire bonding.

Claims

1. A molded power module (2), comprising: a substrate (12) comprising an insulator (4) and an upper conductive layer (5, 6) on the insulator (4), wherein the substrate (12) exposed at a surface of the molded power module (2) comprises a plurality of separate sections (40, 40'), wherein each separate section (40, 40') is at least partially surrounded by a cavity (44) of a storage space of a thermally conductive material (42); at least one semiconductor (10, 10') on the upper conductive layer (5, 6) of the substrate (12); one or more terminals (14, 15, 16, 17) electrically connected to and protruding from the upper conductive layer (5, 6); and a molded portion (30) covering the at least one semiconductor, wherein the molded portion (30) comprises at least two humps (18, 18', 18") protruding from a remaining area of the molded portion (30), wherein the humps (18, 18', 18") are spaced apart from each other, characterized in that the cavity (44) is in fluid communication with a storage structure (48) at least partially surrounding the cavity (44), wherein the storage structure (48) is configured to receive thermally conductive material (42) from the cavity (44) and return thermally conductive material (42) to the cavity (44).

2. The molded power module (2) according to claim 1, characterized in that The humps (18, 18', 18") are arranged above the at least one semiconductor (10, 10').

3. The molded power module (2) according to claim 1 or 2, characterized in that The humps (18, 18', 18") extend above a horizontal plane of the one or more terminals (14, 15, 16, 17).

4. The molded power module (2) according to claim 1 or 2, characterized in that The substrate (12) comprises a lower conductive layer (8) disposed below the insulator (4), wherein the insulator (4) is sandwiched between the upper and lower conductive layers (8).

5. The molded power module (2) according to claim 3, characterized in that The substrate (12) comprises a lower conductive layer (8) disposed below the insulator (4), wherein the insulator (4) is sandwiched between the upper and lower conductive layers (8).

6. The molded power module (2) according to claim 1 or 2, characterized in that An intermediate area (24) is disposed between adjacent humps (18, 18', 18"), the intermediate area having a molded material.

7. The molded power module (2) according to claim 1 or 2, characterized in that An intermediate area (24) is disposed between adjacent humps (18, 18', 18"), the intermediate area having another material (34) different from the molded portion (30).

8. The molded power module (2) according to claim 1 or 2, characterized in that An intermediate area (24) is disposed between adjacent humps (18, 18', 18"), the intermediate area having no material.

9. The molded power module (2) according to claim 8, characterized in that Only the substrate (12) extends completely between adjacent humps (18, 18', 18"), thereby connecting adjacent humps.

10. The molded power module (2) according to claim 1, characterized in that Each separate section (40, 40') is directly below a hump (18, 18', 18").

11. The molded power module (2) according to claim 1 or 10, characterized in that At least some of the cavities (44) are made as cavities (44) in the molded portion (30).

12. The molded power module (2) according to claim 1 or 10, characterized in that At least some of the storage structures (48) are made as storage structures (48) in the molding portion (30).

13. The molded power module (2) according to claim 11, characterized in that At least some of the storage structures (48) are made as storage structures (48) in the molding portion (30).

14. The molded power module (2) according to claim 1 or 10, characterized in that The molding portion (30) surrounds the entire substrate (12) except for the separation portions (40, 40') protruding from the back of the substrate (12) by the molding portion (30).

15. The molded power module (2) according to claim 1 or 10, characterized in that The molding portion (30) covers a top side of the molded power module (2), wherein a back of the substrate (12) is not covered by the molding portion (30).

16. The molded power module (2) according to claim 1 or 2, characterized in that The hump portions (18, 18', 18") comprise a flat top portion (50) and an inclined portion (32, 32') extending from the top portion.

17. A power module assembly (3) comprising a molded power module (2) according to any one of the preceding claims, characterized in that, A heat sink (20) is arranged below the substrate (12) and is in thermal connection with the substrate.

18. The power module assembly (3) according to claim 17, characterized in that A thermally conductive material (42) is provided between the heat sink (20) and the substrate (12).

19. The power module assembly (3) according to claim 17, characterized in that At least some of the cavities (44) are made as cavities (44) in an upper surface of the heat sink (20).

20. The power module assembly (3) according to claim 17, characterized in that At least some of the storage structures (48) are made as storage structures (48) in an upper surface of the heat sink (20).

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