Intelligent Power Module and Encapsulation Method of Intelligent Power Module

Abstract

The present invention relates to an intelligent power module and a packaging method thereof. By providing a stress elimination structure in the portion of the pin within the sealing layer, the stress elimination structure generates elastic deformation when stress is applied, which can effectively reduce the stress of the tensile force and extrusion force transmitted by the pin to the substrate, so that the stress finally transmitted to the insulating layer is greatly reduced, thereby avoiding the generation of cracks in the insulating layer and ultimately resulting in poor packaging, and thus improving the finished product yield of the packaging.

Description

Technical Field

[0001] The present invention relates to an intelligent power module and a packaging method thereof, belonging to the technical field of power semiconductor devices. Background Art

[0002] When packaging an IPM (Intelligent Power Module), due to the industry standard of the thickness tolerance of the aluminum substrate being ±10%, the large tolerance causes the aluminum substrate and the mold to not achieve precise fit, resulting in some errors during the IPM module packaging process. To solve this problem, ejector pins are added in the mold cavity. The ejector pins hold the aluminum substrate tightly against the surface of the cavity to overcome the gap between the aluminum substrate and the cavity caused by the tolerance. However, in the process of module injection molding and packaging, the external force of the ejector pins will cause cracks in the insulating layer of the aluminum substrate, increasing the defective rate during the production of IPM modules. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to solve the problem that during the packaging process of existing IPM modules, due to the large tolerance of the aluminum substrate, cracks in the insulating layer occur in the ejector pin solution, ultimately leading to an increase in the defective rate of module production.

[0004] Specifically, the present invention discloses an intelligent power module, including:

[0005] A substrate, which includes a metal heat dissipation layer, an insulating layer, a wiring layer, and a solder mask layer connected in sequence;

[0006] Multiple electronic components, which are arranged on the wiring layer, and are electrically connected between the multiple electronic components or between the electronic component and the wiring layer;

[0007] Multiple pins, which are arranged at least on one side edge of the substrate, and the pins are electrically connected to the wiring layer;

[0008] A sealing layer, which at least wraps one surface of the substrate where the electronic components are arranged, and one end of the pin exposes from the sealing layer;

[0009] Wherein the pin bends towards the substrate inside the sealing layer to form a bent portion, and a stress relief structure for the stress of the pin on the substrate is further arranged inside the sealing layer, and the stress relief structure generates elastic deformation when stress is applied.

[0010] Optionally, the stress relief structure includes a warped portion, and the bending direction of the warped portion is the same as that of the bent portion.

[0011] Optionally, the warped portion is located in one of the bent segments of the bent portion, and is arranged near the bent part of the bent portion; or the warped portion is arranged at the bent part of the bent portion.

[0012] Optionally, the bending angle of the warping part is 30° to 60°.

[0013] Optionally, the warping part further includes a notch part disposed near the warping part, and the opening direction of the notch is opposite to the opening direction of the warping part.

[0014] Optionally, the notch part is arc-shaped or triangular, and the angle of the triangle is 45° to 90°.

[0015] Optionally, the other surface of the substrate opposite to the surface where the electronic component is disposed is exposed from the sealing layer.

[0016] Optionally, the glass transition temperature of the insulating layer is greater than or equal to 180 °C.

[0017] The present invention also discloses a packaging method for an intelligent power module according to the above, including the following steps:

[0018] Welding a plurality of pins and electronic components on the wiring layer of the substrate;

[0019] Placing the substrate in the cavity of a packaging mold, wherein the packaging mold includes an upper mold and a lower mold arranged up and down, the pins are fixedly arranged between the upper mold and the lower mold, and the free end of the ejector pin arranged on the upper mold abuts against the substrate;

[0020] Injecting a thermoplastic material into the cavity to form a sealing layer;

[0021] Forming and trimming the pins exposed from the sealing layer.

[0022] Optionally, after the step of welding a plurality of pins and electronic components on the wiring layer of the substrate, the following steps are further included:

[0023] Cleaning the substrate;

[0024] Connecting the electronic components with metal wires.

[0025] In the intelligent power module of the present invention, by providing a stress elimination structure in the part of the pin inside the sealing layer, the stress elimination structure generates elastic deformation when stress is applied, and can effectively reduce the stress of the tensile force and extrusion force transmitted from the pin to the substrate, so that the stress finally transmitted to the insulating layer is greatly reduced, thereby avoiding the generation of cracks in the insulating layer and ultimately resulting in poor packaging, thereby improving the finished product yield of the packaging. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of a gap between the substrate and the inner surface of the cavity during the packaging process of an IPM module in the prior art;

[0027] Figure 2 It is a schematic diagram of the packaging structure of the IPM module according to the embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the structure of the substrate according to an embodiment of the present invention;

[0029] Figure 4 Schematic diagram of overflow material generated during the encapsulation process of the IPM module in the prior art;

[0030] Figure 5A and Figure 5B Schematic diagram of cracks generated during the substrate encapsulation process of the IPM module in the prior art;

[0031] Figure 6 Schematic diagram of over - contact between the substrate and the inner surface of the cavity during the encapsulation process of the IPM module in the prior art;

[0032] Figure 7 Schematic diagram of a gap between the substrate and the inner surface of the cavity during the encapsulation process of the IPM module according to an embodiment of the present invention;

[0033] Figure 8 Schematic diagram of over - contact between the substrate and the inner surface of the cavity during the encapsulation process of the IPM module according to an embodiment of the present invention;

[0034] Figure 9 Schematic diagram of the structure of the IPM module according to an embodiment of the present invention;

[0035] Figure 10 Schematic diagram of the structure of the IPM module with another pin shape according to an embodiment of the present invention;

[0036] Figure 11 Schematic diagram of the pin structure with a stress - relieving structure provided on the pin of the IPM module according to an embodiment of the present invention;

[0037] Figure 12 For relative Figure 11 Schematic diagram of the pin structure where the stress - relieving structure is provided at another position of the pin;

[0038] Figure 13 For relative Figure 11 Schematic diagram of the pin structure where the stress - relieving structure is provided at yet another position of the pin.

[0039] Reference numerals:

[0040] IPM module 100, substrate 110, metal heat - dissipation layer 111, insulating layer 112, wiring layer 113, solder mask layer 114, crack 117, pin 120, bending part 121, warping part 122, notch part 123, sealing layer 130, upper mold 210, lower mold 220, ejector pin 230, cavity 240, overflow material 250. Detailed implementation manners

[0041] It should be noted that, without conflict in structure or function, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to examples.

[0042] The present invention provides an intelligent power module. Figure 2 FIG. shows a schematic diagram of the package structure of the IPM module according to an embodiment of the present invention. Referring to Figure 2 , the IPM module 100 includes a substrate 110, a plurality of electronic components (not shown in the figure), a plurality of pins 120, and a sealing layer 130.

[0043] Among them, the substrate 110 includes a metal heat dissipation layer 111, an insulating layer 112, a wiring layer 113, and a solder mask layer 114 connected in sequence. The specific structure of the substrate 110 is as Figure 3 shown, in which the lowermost metal heat dissipation layer 111 occupies most of the volume of the substrate 110, and its thickness is much thicker than that of other layers, generally 0.8 mm to 2 mm, and the commonly used thickness is 1.5 mm, mainly for heat conduction and dissipation. The commonly used material of the metal heat dissipation layer 111 is aluminum and copper, corresponding to an aluminum plate or a copper plate. Connected to the metal heat dissipation layer 111 is the insulating layer 112, whose thickness is relatively thinner than that of the metal heat dissipation layer 111, generally 50 μm to 150 μm, and commonly 110 μm. Then, connected to the metal heat dissipation layer 111 is the wiring layer 113 formed by etching copper foil, and the circuit lines are composed of the etched copper foil. The thickness of the wiring layer is also relatively thin, such as about 70 μm. Finally, a relatively thin solder mask layer 114 is coated on the wiring layer to play a role in circuit isolation and cut off the electrical connection between lines.

[0044] A plurality of electronic components are arranged on the wiring layer 113, and there is an electrical connection between the plurality of electronic components or between the electronic components and the wiring layer 113; the electronic components are electrically connected to the wiring layer 113 by welding.

[0045] A plurality of pins 120 are arranged at least on one side edge of the substrate 110, and the pins 120 are electrically connected to the wiring layer 113; the plurality of pins 120 form a lead frame and are welded to the pads of the wiring layer 113 by welding such as solder paste welding to achieve electrical connection with the wiring layer 113.

[0046] The sealing layer 130 at least wraps one surface of the substrate 110 on which the electronic components are arranged, and one end of the pin 120 protrudes from the sealing layer 130; the sealing layer 130 is mainly formed by an injection molding material, and the material can be resin.

[0047] Among them, the pin 120 is bent towards the substrate 110 within the sealing layer 130 to form a bent portion 121, and a stress relief structure for the stress transmitted by the pin 120 to the substrate 110 is also provided within the sealing layer 130. The stress relief structure undergoes elastic deformation when stress is applied. As Figure 2 shown, the pin 120 is bent substantially downward to form a bent portion 121, so that one end of the pin 120 is welded to the pad. After the electronic component is soldered to the wiring layer 113 of the substrate 110 and the pin 120 is also soldered to the wiring layer 113, the formed semi-finished product is placed in the cavity 240 of the encapsulation mold for injection molding encapsulation. During the high-temperature injection molding process, the insulating layer 112 becomes very fragile, and the soldering position of one end of the pin 120 to the pad will generate stress on the substrate 110 during the injection molding process, including stress formed by upward tensile force or downward extrusion force. This stress is transmitted to the insulating layer 112 through the pin 120, causing it to generate cracks 117, thereby resulting in a short circuit between the wiring layer 113 and the electronic heat dissipation layer, and causing the entire IPM module 100 encapsulation to fail. By providing a stress relief structure on the pin, it can undergo elastic deformation when stress is generated, better eliminating this stress or significantly weakening this stress, so that the force transmitted to the insulating layer 112 is within its tolerable range and does not generate cracks 117. In this way, the stress relief structure within the sealing layer 130 plays a role in avoiding the encapsulation failure caused by the cracks 117 in the insulating layer 112 during the encapsulation process, thereby improving the yield of the encapsulated finished product.

[0048] Figure 1 shows a schematic diagram of the encapsulation structure of an IPM module in the prior art. The difference from the structure of the IPM module 100 in the embodiment of the present invention is that the stress relief structure is missing. Refer to Figure 1 , the encapsulation mold includes an upper mold 210 and a lower mold 220. A movable ejector pin 230 is provided on the upper mold 210. When the upper mold 210 and the lower mold 220 are closed and fixed, an injection molding cavity 240 is formed inside. The processed semi-finished product, that is, the product after the electronic component and the lead frame are both soldered on the circuit layer of the substrate 110, is placed in the encapsulation mold. The free end of the lead frame is crimped and fixed between the upper mold 210 and the lower mold 220. One end of multiple ejector pins 230 abuts against the side of the substrate 110 where the electronic component is installed. The lower surface of the substrate 110, that is, the side of the metal heat dissipation layer 111, faces the lower surface of the cavity 240. Due to the large tolerance of the substrate 110 and the tolerances of the lead frame soldering and the encapsulation mold, the surface of the substrate 110 cannot be properly fitted with the lower surface of the cavity 240, and there will be two situations: gap contact and over-contact. Only when the surface of the substrate 110 is properly fitted with the new surface of the cavity 240 can the result of normal contact be achieved.

[0049] In Figure 1In the middle is the case where the lower surface of the substrate 110 has a gap contact with the lower surface of the cavity 240. There is a small gap between the lower surface of the substrate 110 and the lower surface of the cavity 240. If the cavity 240 is then injection-molded to form the sealing layer 130, during the injection-molding process, the injection material will form an overflow 250 at the position of the gap, as Figure 4 shown. At the intermittent position, the injection material cannot be fully filled and is in small pieces of scattered injection material, thus failing to meet the product standards.

[0050] To eliminate this gap, a downward force is applied to the substrate 110 through the ejector pin 230, causing the substrate 110 to move downward to reach the lower surface of the cavity 240 to achieve normal contact between the two. During the injection-molding process, the injection material forms a fluid state after being heated at a high temperature, making the temperature inside the cavity 240 very high, reaching about 180 °C. At this high temperature, the properties of the insulating layer 112 on the substrate 110 will become brittle, and the downward force applied by the ejector pin 230 to the substrate 110 generates a tensile force between the pin 120 and the wiring layer 113. This force is transmitted to the insulating layer 112, causing cracks 117 to appear in the insulating layer 112 below the pin 120. Specifically, as Figure 5A shown, cracks 117 appear at the end where the pin 120 is welded to the wiring layer 113.

[0051] Figure 6 shows another schematic diagram of the packaging structure of the prior art IPM module 100. In Figure 6 it, there is a situation where the lower surface of the substrate 110 has an over-contact with the lower surface of the cavity 240, that is, the assembly tolerance between the substrate 110 and the lead frame is greater than the depth of the lower surface of the cavity 240. When the upper and lower molds are closed, after the lower surface of the substrate 110 abuts against the lower surface of the cavity 240, the lead frame is higher than the closing surface. Thus, when the molds are closed, there is a squeezing force between the lead frame and the substrate 110. After this pressing force is transmitted to the insulating layer 112, cracks 117 will also appear in the insulating layer 112 under high-temperature conditions. Specifically, as Figure 5B shown, cracks 117 appear at the tail where the pin 120 is welded to the wiring layer 113.

[0052] In the solution of the embodiment of the present invention, as Figure 2 shown, a stress relief structure is provided in the part of the pin 120 located inside the sealing layer 130. This stress relief structure can, when there are Figure 1 and Figure 6 the tensile force and squeezing force between the pin 120 and the wiring layer 113 in the prior art shown, specifically, as Figure 7 shown, in the case where the lower surface of the substrate 110 has a gap contact with the lower surface of the cavity 240, or as Figure 8As shown, there has been a situation where the lower surface of the substrate 110 has come into contact with the lower surface of the cavity 240. In this case, through the elastic deformation generated by the stress relief structure, the above-mentioned tensile force and extrusion force stresses are eliminated or reduced, thereby greatly reducing the stress on the insulating layer 112, avoiding the generation of cracks 117 in the insulating layer 112, improving the product yield, and reducing the process requirements in the packaging process of the IPM module 100, such as the welding tolerance of the lead frame, the basic thickness tolerance, the mold tolerance, etc.

[0053] In some embodiments of the present invention, such as Figure 2 、 Figures 11 to 13 shown, the stress relief structure includes a warping portion 122, and the bending direction of the warping portion 122 is the same as that of the bending portion 121. The bending angle formed by the warping portion 122 is smaller than that of the bending portion 121. Thus, when the pin 120 is subjected to the stresses of tensile force and extrusion force, the warping portion 122 will deform to eliminate or reduce these stresses. The warping portion 122 is preferably arranged close to the bending portion 121, and it can be arranged on one of the bending segments of the bending portion 121. As shown in the schematic structural diagrams of the pin 120 in Figure 12 and Figure 13 , the warping portions 122 are respectively located at the two bending segments of the bending portion 121.

[0054] Or in some other embodiments, the warping portion 122 is arranged at the bending part of the bending portion 121. As shown in Figure 2 and Figure 11 shown, the bending segment of the warping portion 122 coincides with the bending part of the bending portion 121, which facilitates the processing and forming of the pin 120. In order to achieve an effective stress reduction effect, the bending angle of the warping portion 122, such as the A angle in Figures 11 to 13 , is 30 - 60°, and specific values such as 30°, 45°, 50°, and 60° can be selected.

[0055] In some embodiments of the present invention, the warping portion 122 further includes a notch portion 123 arranged close to the warping portion 122, and the opening direction of the notch is opposite to the opening direction of the warping portion 122. Such as Figure 2 、 Figures 11 to 13As shown, a notch portion 123 is provided on one side close to the warping portion 122. The notch portion 123 reduces the diameter of the pin 120. In these figures, the opening direction of the notch is upward, while the opening direction formed by the bending of the warping portion 122 is downward. The combination of the warping portion 122 and the notch portion 123 better relieves stress on the upper and lower sides of the pin 120. When there is a gap between the lower surface of the substrate 110 and the cavity 240, resulting in a tensile force between the pin 120 and the substrate 110, the angle of the warping portion 122 and the notch of the notch portion 123 will increase; when there is over-contact between the lower surface of the substrate 110 and the cavity 240, causing a squeezing force between the pin 120 and the substrate 110, the angle of the warping portion 122 and the notch of the notch portion 123 will decrease, thus effectively relieving these stresses.

[0056] The shape of the notch of the notch portion 123 here can be an arc or a triangle, etc. Preferably, it is a triangle, and the angle range of the triangle is 45° to 90°. For example, specific values such as 60°, 80°, and 89° can be specifically selected. Such as Figures 10 to 12 the B angle in [reference], to form a powerful stress relief effect. When the notch becomes larger or smaller, the corresponding angle will become larger or smaller.

[0057] In order to enable the pin 120 to meet the required current-carrying capacity, the depth of its notch needs to be controlled and cannot be too deep. Generally, the diameter of the pin 120 at the notch portion 123 is one-third to four-fifths of the diameter at other positions, and finally the diameter of the pin 120 is greater than 200 μm.

[0058] In some embodiments of the present invention, the other surface of the substrate 110 opposite to the electronic component is exposed from the sealing layer 130. In this embodiment, the IPM module 100 is a semi-encapsulated structure. Such as Figure 2 shown, during its encapsulation, the injection-molded sealing layer 130 covers the side of the substrate 110 where the electronic component and the pin 120 are installed, while the other side, that is, the side of the metal heat dissipation layer 111, will not be covered by the injection-molded material because it is in contact with the lower surface of the cavity 240. Thus, finally, the side of the metal heat dissipation layer 111 is exposed after encapsulation. The finished product after encapsulation is as shown in Figure 9 and Figure 10As shown, one side of the metal heat dissipation layer 111, such as an aluminum plate, is exposed, which is more conducive to the heat dissipation of the IPM module 100. For the IPM module 100 with such a semi-encapsulation structure, during the encapsulation process, due to the large tolerance of the substrate 110, it is easy to have over-contact or gaps between the surface of the substrate 110 and the cavity 240. The stress elimination structure of the present invention can effectively reduce the stress of the extrusion force and tensile force between the pin 120 and the substrate 110 caused by over-contact or gaps, thereby avoiding the cracks in the insulating layer 112 of the substrate 110 caused by these stresses during the encapsulation process, making the encapsulation of the IPM module 100 unable to meet the product requirements. Therefore, the stress elimination structure of the present invention can effectively improve the finished product yield of the encapsulation of the IPM module 100.

[0059] Of course, in other embodiments, the IPM module 100 may also be a fully encapsulated structure, and the injection molding material completely covers the entire substrate 110. During the encapsulation process, the injection molding material such as resin will also generate stress on the substrate 110. The stress elimination structure of the present invention can also effectively reduce these stresses.

[0060] In some embodiments of the present invention, in order to further improve the strength of the insulating layer 112 of the substrate 110 at high temperatures, an insulating layer material with a glass transition temperature parameter greater than or equal to 180 °C can be used. In the existing industry, the glass transition temperature of the insulating layer 112 is commonly 150 °C. When the IPM module 100 is encapsulated, the temperature in the mold cavity 240 can reach 180 °C. At this high temperature, the material of the insulating layer 112 becomes brittle, so it is easy to generate cracks 117 even under a slight external force. By using an insulating layer 112 with a higher glass transition temperature, such as 180 °C, its strength is significantly improved at the high temperature of 180 °C of the mold, so it is not easy to generate cracks 117 when subjected to external forces, thereby improving the yield of the product encapsulation.

[0061] The present invention also proposes a packaging method for an intelligent power module. Here, the intelligent power module is the IPM module 100 mentioned in the above embodiments. The packaging method includes the following steps:

[0062] Step S100, welding a plurality of pins 120 and electronic components on the wiring layer 113 of the substrate 110;

[0063] Step S200, placing the substrate 110 in the cavity 240 of the packaging mold, where the packaging mold includes an upper mold 210 and a lower mold 220 arranged up and down. The pins 120 are fixedly arranged between the upper mold 210 and the lower mold 220, and the free end of the ejector pin 230 arranged on the upper mold 210 abuts against the substrate 110;

[0064] Step S300, injecting a thermoplastic material into the cavity 240 to form a sealing layer 130.

[0065] Step S400: Shape and trim the pins 120 exposed from the sealing layer 130.

[0066] In step S100, the shaping of the substrate 110 can be achieved through the following steps:

[0067] Design a metal heat dissipation layer 111 of the substrate 110, such as an aluminum plate, with a suitable size according to the circuit layout of the IPM module 100. Generally, the thickness of the aluminum plate is 1.5 mm.

[0068] Apply an insulating material and copper material in a hot pressing manner so that the insulating material forms on the surface of the aluminum plate as the insulating layer 112, and the copper material forms on the surface of the insulating layer 112 as the copper foil layer. To improve the withstand voltage characteristics, the thickness of the insulating layer 112 can be designed to be 110 μm, and to improve the current-carrying capacity, the thickness of the copper foil layer can be designed to be 0.07 mm.

[0069] Etch specific positions of the copper foil layer to form a circuit wiring layer 113 and pin pads.

[0070] Apply green oil between the circuit wirings to form a green oil layer 114.

[0071] Assemble electronic components on the surface of the circuit wiring layer 113. Generally, the electronic components and pins 120 can be soldered to the circuit wiring layer 113 through a solder paste soldering process to form a semi-finished product before encapsulation.

[0072] In this step, it may further include placing the substrate 110 after soldering the electronic components and pins 120 into a cleaning machine for cleaning to remove foreign matters such as residual flux during the soldering process.

[0073] And after the cleaning is completed, according to the requirement of the current-carrying capacity, a suitable aluminum wire can be selected as the metal wire of the bonding wire to connect the electronic components in one step. Finally, a semi-finished product before encapsulation is formed.

[0074] In step S200, place the semi-finished substrate 110 in the mold cavity 240. The mold cavity 240 is as Figure 2As shown, the encapsulation mold includes an upper mold 210 and a lower mold 220. A movable ejector pin 230 is provided on the upper mold 210. When the upper mold 210 and the lower mold 220 are closed and fixed up and down, a cavity 240 for injection molding and encapsulation is formed inside. The product after welding the processed semi-finished products, namely electronic components and lead frames, on the circuit layer of the substrate 110 is placed in the encapsulation mold. The free end of the lead frame is press-fitted and fixed between the upper mold 210 and the lower mold 220. One end of multiple ejector pins 230 abuts against the side of the substrate 110 where the electronic components are installed. The lower surface of the substrate 110, that is, the side of the metal heat dissipation layer 111, faces the lower surface of the cavity 240. Through the retractable ejector pin 230, the lower surface of the substrate 110 is brought into contact and fit with the inner surface of the cavity 240, achieving as Figure 2 the effect in

[0075] In step S300, a thermoplastic material such as resin is injected into the mold cavity 240 until the entire cavity 240 is filled. The temperature inside the cavity 240 during the injection of the resin material is generally about 180°C. After cooling, the thermoplastic material forms a sealing layer 130, so that the side of the substrate 110 where the electronic components are installed is completely covered by the sealing layer 130, while the other side of the substrate 110, that is, the metal heat dissipation layer 111, is exposed, and at the same time, the pins 120 are also partially exposed. During the injection of the thermoplastic material, although the high temperature inside the cavity 240 causes the material of the insulating layer 112 of the substrate 110 to become brittle, since a stress relief structure is provided in the part of the pins 120 in the cavity 240, specifically the warping part 122 or the notch part 123 is added at the same time, it can effectively reduce the stress of the tensile force and extrusion force transmitted from the pins 120 to the substrate 110, so that the stress finally transmitted to the insulating layer 112 is greatly reduced, thereby avoiding the generation of cracks 117 in the insulating layer 112 and ultimately resulting in poor encapsulation.

[0076] In step S400, the pins 120 exposed from the sealing layer 130 are shaped and trimmed neatly to form pins 120 for dual in-line package as Figure 8 shown, or pins 120 for surface mount package as Figure 9 shown. To adapt to different ways of installing the IPM module 100 on the electric control board.

[0077] For the encapsulation method of the IPM module 100 of the present invention, by setting a stress relief structure in the part of the pins 120 inside the sealing layer 130, the stress during the injection molding and encapsulation process inside the cavity 240 is effectively reduced, thereby avoiding the generation of cracks in the insulating layer 112 of the substrate 110, and thus greatly improving the yield of the product.

[0078] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0079] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0080] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0081] In the present invention, unless otherwise clearly specified and limited, terms such as "install", "connect", "connection", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact via an intermediate medium. Further, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature has a higher level of height than the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level of height than the second feature.

[0083] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An intelligent power module, characterized in that, it includes: a substrate, which includes a metal heat dissipation layer, an insulating layer, a wiring layer, and a solder mask layer connected in sequence; a plurality of electronic components, which are arranged on the wiring layer, and are electrically connected between the plurality of electronic components or between the electronic components and the wiring layer; a plurality of pins, which are arranged at at least one side edge of the substrate, and the pins are electrically connected to the wiring layer; a sealing layer, which at least wraps one surface of the substrate where the electronic components are arranged, and one end of the pin exposes from the sealing layer; wherein the pin bends towards the substrate in the sealing layer to form a bent portion, and a stress relief structure for the stress of the pin on the substrate is also arranged inside the sealing layer, and the stress relief structure generates elastic deformation when the stress is applied; the stress relief structure includes a warped portion, and the bending direction of the warped portion is the same as that of the bent portion; the bending angle formed by the warped portion is smaller than that of the bent portion; the warped portion is located in one of the bent segments of the bent portion, and the warped portion is arranged close to the bend of the bent portion; or the warped portion is arranged at the bend of the bent portion; the bending angle of the warped portion is 30° to 60°; the warped portion further includes a notch portion arranged close to the warped portion, and the opening direction of the notch is opposite to the opening direction of the warped portion; the notch portion is arc-shaped or triangular, and the angle of the triangle is 45° to 90°; the other surface of the substrate opposite to the surface where the electronic components are arranged exposes from the sealing layer; the glass transition temperature of the insulating layer is greater than or equal to 180 °C.

2. A packaging method for the intelligent power module according to claim 1, including the following steps: welding a plurality of pins and electronic components on the wiring layer of the substrate; placing the substrate in the cavity of a packaging mold, wherein the packaging mold includes an upper mold and a lower mold arranged up and down, the pins are fixedly arranged between the upper mold and the lower mold, and the free end of the ejector pin arranged on the upper mold abuts against the substrate; injecting a thermoplastic material into the cavity to form a sealing layer; forming and trimming the pins that expose from the sealing layer.

3. According to the packaging method described in claim 2, characterized in that, after the step of welding a plurality of pins and electronic components on the wiring layer of the substrate, it further includes: cleaning the substrate; connecting the electronic components with metal wires.

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