A power module structure

Abstract

The present invention relates to a power module structure, which comprises a shell, a substrate, a bottom plate, a chip and a filling material. The shell is a hollow structure, comprising a grid body, the two sides of which are connected to the shell, and the upper end is gap-matched with the shell. The bottom plate is fixedly arranged at the lower end of the shell, the substrate is arranged on the bottom plate, the chip is electrically connected to the upper end of the substrate, and the filling material is filled in the hollow structure. Among them, the position of the grid body does not correspond to the chip, the lower end of the grid body extends into the filling material, a part of the filling material is separated on both sides of the grid body, and the volume of the filling material in the area on both sides of the grid body is reduced. After the filling material is solidified, the size of the stress concentration in the area near the grid body is reduced, the stress distribution state is improved, the possibility of cracks in the filling material and the cracks spreading to the vicinity of the chip is reduced, and the service life of the power module is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of power modules, and in particular to a power module structure. Background Art

[0002] Figure 1 The schematic diagram of the power module structure in the prior art is shown as follows: Figure 1 As shown, the power module generally includes a substrate, a chip, a filling medium and a housing stacked in sequence. In order to improve the heat resistance of the power module, an epoxy resin material with a high glass transition temperature is generally used, which makes the hardness of the epoxy resin higher and higher, especially in large-sized power modules. Figure 2 The internal stress distribution diagram of epoxy resin in the prior art is shown as follows: Figure 2 As shown, after a large volume of epoxy resin is cured, the internal stress is large and stress concentration is likely to occur in the chip and its adjacent areas, increasing the risk of cracks in the epoxy resin. The cracks extend to the vicinity of the chip and easily cause chip damage.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] In view of the deficiencies in the prior art, an embodiment of the present invention discloses a power module structure to solve the problem of large and concentrated stress generated by epoxy resin in the power module.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A power module structure, the power module comprises: a shell, which is a hollow structure, including: a grid body, both sides of which are connected to the shell, and the upper end is loosely matched with the shell; a substrate, which is arranged at the lower end of the shell; a chip, which is electrically connected to the upper end of the substrate; and a filling material, which is filled in the hollow structure; wherein the position of the grid body does not correspond to the chip, and the lower end of the grid body extends into the filling material, separating a portion of the filling material on both sides of the grid body.

[0007] A further technical solution is that the lower end of the grid body is connected to the substrate.

[0008] A further technical solution is that the lower end of the grid body is gap-matched with the upper end of the substrate.

[0009] A further technical solution is that grooves are symmetrically provided on both sides of the lower end of the grid body.

[0010] A further technical solution is that the grid body is detachably connected to the shell.

[0011] A further technical solution is that the shell comprises: slots arranged on both sides of the shell; wherein the grid body is inserted into the slots.

[0012] A further technical solution is that the grid body has a cavity inside.

[0013] A further technical solution is that the power module also includes: a connector electrically connecting the chip and the substrate; wherein, when the connector passes through the lower end of the gate body, the gate body is bonded to the substrate; when the connector does not pass through the lower end of the gate body, the gate body is bonded or welded to the substrate.

[0014] A further technical solution is that the substrate is a copper clad plate.

[0015] The beneficial effects of the embodiments of the present invention are as follows:

[0016] (I) When installing the power module of the present invention, the outer shell connected to the gate body on both sides is first fixedly connected to the substrate, and the filling material is injected into the interior. The gate body separates part of the filling material on both sides of the gate body, thereby reducing the volume of the filling material in the area on both sides of the gate body. After the filling material is solidified, the stress is concentrated on the surface of the gate body close to the substrate, thereby improving the stress distribution state, reducing the size of the stress concentration, reducing the possibility of cracks in the filling material and the possibility of cracks spreading to the vicinity of the chip, and improving the service life of the power module.

[0017] (II) Furthermore, the gap between the lower end of the gate body and the upper end of the substrate is matched, and part of the filling material is separated on both sides of the gate body by the gate body connected to the two sides of the shell, reducing the volume of the filling material in the area on both sides of the gate body. After the filling material is cured, the stress is concentrated on the two sides of the lower end of the gate body and the bottom surface, improving the stress distribution state, and significantly reducing the stress concentration of the filling material on the chip surface, reducing the possibility of cracks in the filling material and cracks spreading to the vicinity of the chip, thereby improving the service life of the power module. At the same time, since the filling materials at the lower end of the gate body are interconnected, the hidden danger of interface stratification of dissimilar materials between the sealant, the filling material and the separation gate due to the presence of the sealant is avoided, thereby improving the reliability of the power module.

[0018] (iii) Furthermore, the grid body and the shell are detachably connected. During installation, the filling material can be first injected into the shell, and then the grid body is inserted into the slot, and finally the filling material is solidified to prevent the partition grid from affecting the flow of the filling material and to prevent defects such as residual pores at the bottom of the grid body when the filling material flows, thereby ensuring the product quality of the power module.

[0019] (iv) Furthermore, by setting the gate body to a hollow structure, even if the physical properties of the filling material and the gate body are similar and well combined, it can be ensured that the stress concentration is completely introduced into the bottom of the gate body with a smaller cross-sectional area, so that the stress concentration generated by the filling material on the chip surface is significantly reduced, reducing the possibility of cracks in the filling material and the possibility of cracks spreading to the vicinity of the chip, thereby improving the service life of the power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of a power module in the prior art.

[0021] Figure 2 This is a diagram showing the internal stress distribution of epoxy resin in a power module of the prior art.

[0022] Figure 3 FIG. 1 is a schematic diagram of a power module structure according to the first embodiment of the present invention.

[0023] Figure 4 FIG. 1 is a diagram showing the internal stress distribution of epoxy resin in a power module structure according to the first embodiment of the present invention.

[0024] Figure 5 FIG. 4 is a schematic diagram of a power module structure according to a second embodiment of the present invention.

[0025] Figure 6 FIG. 4 is a schematic diagram of the flow direction of filling material in a power module structure according to the second embodiment of the present invention.

[0026] Figure 7 It is a schematic structural diagram of a power module structure in which grooves are provided on both sides of a gate body in a second embodiment of the present invention.

[0027] Figure 8 FIG. 4 is a cross-sectional view of a power module structure according to a second embodiment of the present invention.

[0028] Fig. 9 This is an axonometric diagram of a power module structure according to the third embodiment of the present invention, in a state where a gate body is not inserted into a slot.

[0029] Fig.10 This is an axonometric diagram of a power module structure according to a third embodiment of the present invention, showing a gate body inserted into a slot.

[0030] Fig.11 It is a schematic diagram of the flow direction of the filling material in a state where a gate is inserted into a slot in a power module structure according to the third embodiment of the present invention.

[0031] Fig.12 It is a schematic diagram of the flow direction of the filling material in a power module structure according to the third embodiment of the present invention when the gate body is not inserted into the slot.

[0032] Fig.13 FIG. 4 is an isometric view of a power module structure according to a fourth embodiment of the present invention.

[0033] Fig.14 FIG. 4 is a cross-sectional view of a power module structure according to a fourth embodiment of the present invention.

[0034] Fig.15 FIG. 4 is a diagram showing the internal stress distribution of a filling material in a power module structure according to the fourth embodiment of the present invention.

[0035] In the figure:

[0036] 1. Shell; 11. Slot; 12. Injection hole; 2. Gate body; 21. Groove; 22. Cavity; 3. Chip; 4. Substrate; 5. Bottom plate; 6. Filling material; 7. Connector; 8. Terminal. DETAILED DESCRIPTION

[0037] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the device proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings adopt a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated by the accompanying drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0039] First embodiment:

[0040] This embodiment discloses a power module structure.

[0041] Figure 3 FIG. 1 is a schematic diagram of a power module structure according to the first embodiment of the present invention. Figure 3As shown, the power module includes a housing 1, a substrate 4, a bottom plate 5, a chip 3 and a filling material 6. The housing 1 is a hollow structure, including a grid body 2, the two sides of which are connected to the housing 1, and the upper end is loosely matched with the housing 1. The bottom plate 5 is fixedly arranged at the lower end of the housing 1, the substrate 4 is arranged on the bottom plate 5, the chip 3 is electrically connected to the upper end of the substrate 4, and the filling material 6 is filled in the hollow structure. Among them, the position of the grid body 2 does not correspond to the chip 3, and the lower end of the grid body 2 extends into the filling material 6, separating a part of the filling material 6 on both sides of the grid body 2.

[0042] Exemplarily, the lower end of the housing 1 is connected to the bottom plate 5 by dispensing. The filling material 6 is an insulating heat dissipation material, preferably an epoxy resin. Both sides of the grid body 2 are bonded to the inner side of the housing 1. The grid body 2 can also be integrally injection molded with the housing 1. The position of the grid body 2 corresponds to the upper surface of the substrate 4 between adjacent chips 3 or the upper surface of the substrate 4 between the chip 3 and the housing 1.

[0043] Furthermore, the lower end of the gate body 2 is connected to the substrate 4. Exemplarily, the substrate 4 is a copper clad plate.

[0044] Further, the power module also includes a connector 7, which electrically connects the chip 3 and the substrate 4. Exemplarily, the connector 7 is a sheet or a binding wire. When the connector 7 passes through the lower end of the grid body 2, the grid body 2 is connected to the substrate 4 by a sealant. When the connector 7 does not pass through the lower end of the grid body 2, the grid body 2 can be connected to the substrate 4 by a sealant, or can pass through the substrate 4 and be connected to the bottom plate 5 by a sealant.

[0045] Furthermore, the power module further includes a terminal 8 , the terminal 8 is electrically connected to the substrate 4 , and the terminal 8 is connected to an external circuit board.

[0046] During installation of this embodiment:

[0047] Step S1 , welding the metal bottom plate 5 to the substrate 4 , and electrically connecting the chip 3 , the terminal 8 and other electronic components to the substrate 4 .

[0048] Step S2 , electrically connecting the chip 3 and the substrate 4 via the connecting member 7 .

[0049] Step S3, connecting the housing 1 with the grid body 2 to the metal bottom plate 5 by glue spotting.

[0050] Step S4, injecting the filling material 6 into the shell 1 and solidifying it into shape.

[0051] In this embodiment, the filling material 6 is completely separated on both sides of the grid body 2 by connecting the grid body 2 on both sides of the housing 1, thereby reducing the volume of the filling material 6 in the area on both sides of the grid body 2. Figure 4As shown, after the filling material 6 is cured, the stress is concentrated at the connection between the gate body 2 and the substrate 4, which improves the stress distribution state. The stress concentration generated by the filling material 6 on the surface of the chip 3 is significantly reduced, which reduces the possibility of cracks in the filling material 6 and the possibility of cracks spreading to the vicinity of the chip 3, thereby improving the service life of the power module.

[0052] Second embodiment:

[0053] Based on the first embodiment, the second embodiment is further optimized and refined.

[0054] Figure 5 FIG. 1 is a schematic diagram of a power module structure according to a second embodiment of the present invention. Figure 5 As shown, the lower end of the grid body 2 is gap-matched with the upper end of the substrate 4. Exemplarily, the substrate 4 is a copper-clad board.

[0055] Figure 6 FIG. 2 is a schematic diagram of the flow direction of the filling material in a power module structure according to the second embodiment of the present invention. Figure 6 As shown, specifically, the filling material 6 is injected from the injection holes 12 on the left and right sides of the shell 1. When the filling material 6 flows toward the middle, its fluidity gradually weakens. The filling material 6 cannot fill the gap between the gate body 2 and the substrate 4 in time, resulting in residual pores.

[0056] Figure 7 It is a schematic structural diagram of a power module structure in which grooves are provided on both sides of a gate body in a second embodiment of the present invention. Figure 8 FIG. 2 is a cross-sectional view of a power module structure according to a second embodiment of the present invention. Figure 7 and Figure 8 As shown, preferably, grooves 21 are symmetrically provided on both sides of the lower end of the grid body 2. Exemplarily, the length of the grid body 2 at the grooves 21 changes from small to large from the lower end to the upper end, so that when the filling material 6 is injected into the shell 1, the flow space of the filling material 6 at both sides of the grid body 2 is increased to discharge the internal gas as much as possible.

[0057] In this embodiment, part of the filling material 6 is separated on both sides of the grid body 2 by connecting the grid body 2 on both sides of the housing 1, reducing the volume of the filling material 6 in the area on both sides of the grid body 2. After the filling material 6 is cured, the stress is concentrated on both sides of the lower end of the grid body 2 and the bottom surface, improving the stress distribution state, and significantly reducing the stress concentration of the filling material 6 on the surface of the chip 3, reducing the possibility of cracks in the filling material 6 and the possibility of cracks spreading to the vicinity of the chip 3, thereby improving the service life of the power module. At the same time, since the filling material 6 at the lower end of the grid body 2 is interconnected, the hidden danger of interface delamination of different materials between the sealant, the filling material 6 and the separation grid due to the presence of the sealant is avoided.

[0058] Third embodiment:

[0059] Based on the second embodiment, the third embodiment further optimizes and refines the gate body 2 .

[0060] Fig. 9 This is an axonometric diagram of a power module structure according to the third embodiment of the present invention, in a state where a gate body is not inserted into a slot. Fig.10 FIG. 1 is an isometric view of a power module structure according to a third embodiment of the present invention, in which a gate body is inserted into a slot. Fig. 9 and Fig.10 As shown, the grid body 2 is detachably connected to the housing 1 .

[0061] Exemplarily, the housing 1 includes slots 11 disposed on both sides of the housing 1 , wherein the grid body 2 is inserted into the slots 11 .

[0062] Fig.11 FIG. 1 is a schematic diagram of the flow direction of the filling material in a power module structure of the third embodiment of the present invention when the gate body is inserted into the slot. Fig.11 As shown, if the gate body 2 is inserted first and then the filling material 6 is injected, the filling material 6 will accumulate at the bottom, which may cause the following problems: Figure 6 Defects such as residual pores shown.

[0063] Fig.12 FIG. 1 is a schematic diagram of the flow direction of the filling material in a power module structure according to the third embodiment of the present invention when the gate body is not inserted into the slot. Fig.12 As shown, during installation, the filling material 6 can be first injected into the housing 1, and then the grid body 2 can be inserted into the slot 11. Finally, the filling material 6 is solidified. The filling material 6 flows more evenly, preventing defects such as residual pores at the bottom of the grid body when the filling material 6 flows, thereby ensuring the product quality of the power module.

[0064] Fourth embodiment:

[0065] Based on any of the above embodiments, the fourth embodiment further optimizes and refines the gate body 2 .

[0066] Fig.13 FIG. 4 is an isometric view of a power module structure according to a fourth embodiment of the present invention. Fig.14 FIG. 4 is a cross-sectional view of a power module structure according to a fourth embodiment of the present invention. Fig.13 and Fig.14 As shown, the gate body 2 has a cavity 22 inside. Exemplarily, the gate body 2 has at least one set of bent portions, and the cavity 22 is formed inside the bent portions. The thickness of the cavity 22 is determined according to the distribution of components inside the power module. Each bent portion can be composed of at least three plates connected, and adjacent plates are perpendicular to each other, or composed of at least one arc-shaped plate.

[0067] When the grid body 2 does not have a cavity 22 inside, if the filling material 6 and the grid body 2 have similar physical properties, and the filling material 6 and the grid body 2 have good surface bonding, after the filling material 6 solidifies, the filling material 6 and the grid body 2 are equivalent to one body, so the stress distribution inside the filling material 6 is not changed, and the stress distribution is approximately Figure 2 situation. Fig.15 FIG. 4 is a diagram showing the internal stress distribution of the filling material in a power module structure according to the fourth embodiment of the present invention. Fig.15 As shown, if the grid body 2 adopts the cavity 22, even if the grid body 2 has physical properties similar to those of epoxy resin, since the structure itself is hollow, the stress will be concentrated at the place with the smallest cross-sectional area.

[0068] In this embodiment, by setting the gate body 2 as a hollow structure, even if the physical properties of the materials used for the filling material 6 and the gate body 2 are similar and well combined, it is possible to ensure that the stress concentration is completely introduced into the bottom of the gate body 2 with a smaller cross-sectional area, thereby ensuring that the stress distribution state can be improved, and the stress concentration generated by the filling material 6 on the surface of the chip 3 is significantly reduced, thereby reducing the possibility of cracks in the filling material 6 and the possibility of cracks spreading to the vicinity of the chip 3, thereby improving the service life of the power module.

[0069] In addition, in the above embodiment, the connecting member 7 is made of at least one of aluminum, copper, gold and silver.

[0070] In addition, in the above embodiments, the electrical connection is achieved by any one of laser, ultrasonic bonding, sintering and welding.

[0071] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A power module structure, characterized in that: The power module comprises: The shell is a hollow structure, including: A grid body, with two sides connected to the shell and an upper end having a clearance fit with the shell; A substrate is arranged at the lower end of the inner part of the shell; A chip, electrically connected to the upper end of the substrate; A filling material filled in the hollow structure; The position of the gate body does not correspond to the chip, the lower end of the gate body extends into the filling material, the lower end of the gate body is gap-matched with the upper end of the substrate, and a part of the filling material is separated on both sides of the gate body; The filling material is injected from the injection holes on the left and right sides of the shell, and grooves are symmetrically provided on both sides of the lower end of the grid body; the length of the grid body at the groove changes from small to large from the lower end to the upper end; The grid body is detachably connected to the shell; The housing comprises: Slots are arranged on both sides of the shell; Wherein, the gate body is inserted into the slot.

2. A power module structure according to claim 1, characterized in that: The grid body has a cavity inside.

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