High-reliability PCB packaging structure

Abstract

The utility model, which relates to the technical field of device packaging, discloses a high-reliability PCB packaging structure comprising a PCB substrate group comprising a plurality of PCB substrates. A plurality of grooves are formed in the PCB substrate, a chip is packaged in each groove, and the grooves are matched with the chips packaged in the grooves; when at least two chips are packaged on the same PCB substrate, the chips packaged on the same PCB substrate are electrically connected through the first flexible PCB film; when the PCB substrate group comprises at least two PCB substrates, any two PCB substrates in the PCB substrate group are electrically connected through the second flexible PCB film; and the second flexible PCB film is connected with the PCB substrate connected with the second flexible PCB film through the first flexible PCB film or the chip. The packaging structure is flexible and changeable, and the reliability and the integration degree of packaging are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of device packaging, in particular to a high-reliability PCB packaging structure. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor) is a new type of composite device that combines the advantages of power field effect tubes and power transistors. It has the high-speed switching and voltage drive characteristics of MOSFET and the low saturation voltage characteristics of bipolar transistors. It is easy to achieve large current capabilities. It has the advantages of high input impedance, fast operating speed, good thermal stability and simple drive circuit, as well as low on-state voltage, high withstand voltage and large current. It is widely used in motor drive and other fields.

[0003] At present, several IGBTs are usually packaged into IGBT modules. Most existing IGBT modules use ordinary DBC packaging, which requires a lot of fixtures and jigs during packaging operations, and the packaging process is cumbersome. In addition, DBC (copper-clad ceramic) is usually designed as a specific packaging module, which has great layout limitations and a large fixed packaging volume, and cannot be flexibly adapted to a variety of packaging solutions.

[0004] Moreover, with the wide application of IGBT modules in various fields, there are more stringent requirements for the integration and reliability of IGBT modules. Traditional DBC packaging structures mostly use aluminum wire bonding to achieve IGBT interconnection. The aluminum wire bonding is prone to breakage and failure, which greatly affects the reliability of IGBT modules. Utility Model Content

[0005] In view of the above problems and technical requirements, the inventors have proposed a high-reliability PCB packaging structure.

[0006] The technical solution of the utility model is as follows:

[0007] A high-reliability PCB packaging structure includes a PCB substrate group, wherein the PCB substrate group includes a plurality of PCB substrates;

[0008] The PCB substrate is provided with a plurality of grooves, each of which is encapsulated with a chip, and the grooves are adapted to the chip encapsulated in the grooves;

[0009] When at least two chips are packaged on the same PCB substrate, the chips packaged on the same PCB substrate are electrically connected through the first flexible PCB film;

[0010] When the PCB substrate group includes at least two PCB substrates, any two PCB substrates in the PCB substrate group are electrically connected through the second flexible PCB film;

[0011] The second flexible PCB film is connected to the connected PCB substrate via the first flexible PCB film or chip.

[0012] A further technical solution is that the PCB substrate comprises a first dielectric layer, a second dielectric layer and a metal layer, and the metal layer is located between the first dielectric layer and the second dielectric layer;

[0013] For any groove on the PCB substrate, the bottom of the groove corresponds to the metal layer;

[0014] A welding piece is arranged in the groove, the welding piece is in contact with the metal layer, and the chip packaged in the groove is welded to the metal layer through the welding piece.

[0015] A further technical solution is that the second flexible PCB film includes a plurality of main circuits, and any main circuit includes a filtering unit;

[0016] The filtering unit includes a capacitor C1, an inductor L1 and an inductor L2, and one end of the inductor L1 is connected to one end of the inductor L2 through a first lead;

[0017] One end of the capacitor C1 is connected to one end of the inductor L1 and one end of the inductor L2 through a second lead, and the other end of the capacitor C1 is grounded through a ground lead.

[0018] A further technical solution is that the main circuit further includes a first pad, a second pad, a third pad, a first pin and a ground pin;

[0019] The second pad is located between the first pad and the third pad, the inductor L1 is welded on the first pad, the capacitor C1 is welded on the second pad, and the inductor L2 is welded on the third pad;

[0020] One end of the inductor L1 is connected to the first pin through a third lead, one end of the capacitor C1 is connected to the ground pin through a ground lead, and one end of the inductor L2 is connected to the first flexible PCB film through a fourth lead.

[0021] A further technical solution is that the first flexible PCB film includes a plurality of metal areas and a plurality of flexible areas connecting adjacent metal areas, and connecting leads for realizing electrical connection between adjacent metal areas are arranged in the flexible areas.

[0022] A further technical solution is that the chip includes an IGBT chip, and the IGBT chip includes a front side and a back side corresponding to the front side;

[0023] The front side of the IGBT chip includes an emitter welding area group, the emitter welding area group includes a plurality of emitter welding areas, and adjacent emitter welding areas are insulated and isolated by a first trench;

[0024] The emitter pads in the emitter pad group are connected to the metal pads in the first flexible PCB film in a one-to-one correspondence, and the flexible pads connecting the adjacent metal pads are suspended on the front side of the IGBT chip.

[0025] A further technical solution is that the front side of the IGBT chip also includes a gate electrode welding area, and the gate electrode welding area is insulated and isolated from the emitter electrode welding area by a second channel;

[0026] The gate pad is connected to a gate drive circuit disposed in the third flexible PCB film.

[0027] A further technical solution is that a plurality of heat dissipation holes and a plurality of positioning holes are arranged on the PCB substrate.

[0028] A further technical solution is that the material used for the first lead, the second lead, the third lead, the fourth lead and the ground lead includes Au.

[0029] A further technical solution is that the depth of the groove on the PCB substrate is not less than the cross-sectional thickness of the chip packaged in the corresponding groove.

[0030] The beneficial technical effects of the utility model are:

[0031] The present invention abandons the traditional DBC packaging solution and adopts a high-reliability PCB packaging structure, in which a plurality of grooves adapted to the chip are arranged on the PCB substrate to package the chip on the PCB substrate. The packaging structure does not require the use of multiple fixtures during the packaging operation, avoids redundant fixture design, and simplifies the packaging process. In addition, the packaging structure is flexible and changeable, reduces the packaging volume while reducing layout limitations, and can adapt to a variety of packaging solutions.

[0032] Moreover, in the utility model, the chips packaged on the same PCB substrate are electrically connected via a first flexible PCB film, and every two PCB substrates in the PCB substrate group are electrically connected via a second flexible PCB film. The flexible PCB film is not easy to break and can be internally integrated with an integrated circuit. By routing wires inside the flexible PCB film instead of the traditional aluminum wire bonding method, the reliability of the packaging structure and the integration of the packaging can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a cross-sectional view of an embodiment of a high-reliability PCB packaging structure provided by the utility model.

[0034] Figure 2 It is a structural schematic diagram of an embodiment of the first flexible PCB film and the second flexible PCB film provided by the utility model.

[0035] Figure 3 This is a circuit schematic diagram of an embodiment of a filter unit provided by the utility model.

[0036] Figure 4 It is a schematic diagram of an embodiment of a PCB substrate provided by the utility model.

[0037] Figure 5 This is a connection diagram of an embodiment of the first flexible PCB film provided by the utility model.

[0038] Figure numerals: 1-PCB substrate, 2-groove, 3-soldering piece, 4-first dielectric layer, 5-metal layer, 6-second dielectric layer, 7-heat dissipation hole, 8-positioning hole, 9-gate lead, 10-chip, 11-emitter welding area, 12-gate welding area, 13-first channel, 14-second channel, 100-first flexible PCB film, 101-metal area, 102-flexible area, 103 connecting lead, 200-second flexible PCB film, 201-first soldering pad, 202-second soldering pad, 203-third soldering pad, 211-first lead, 212-second lead, 213-third lead, 214-fourth lead, 215-ground lead, 221-first pin, 222-ground pin. DETAILED DESCRIPTION

[0039] The specific implementation of the utility model is further described below in conjunction with the accompanying drawings.

[0040] In order to improve the reliability and integration of packaging, the utility model provides a high-reliability PCB packaging structure, including a PCB substrate group, wherein the PCB substrate group includes a plurality of PCB substrates 1;

[0041] The PCB substrate 1 is provided with a plurality of grooves 2, each groove 2 being encapsulated with a chip 10, and the grooves 2 are adapted to the chip 10 encapsulated in the grooves 2;

[0042] When at least two chips are packaged on the same PCB substrate, the chips packaged on the same PCB substrate are electrically connected through the first flexible PCB film;

[0043] When the PCB substrate group includes at least two PCB substrates, any two PCB substrates in the PCB substrate group are electrically connected through the second flexible PCB film;

[0044] The second flexible PCB film is connected to the connected PCB substrate via the first flexible PCB film or chip.

[0045] Specifically, the PCB substrate is a rigid circuit printed board commonly used by personnel in the field of this technology. Generally, the PCB substrate 1 includes a front side and a back side corresponding to the PCB substrate 1. The groove 2 is arranged on the front side of the PCB substrate 1. A chip 10 is encapsulated in each groove 2. The manner in which the chip 10 is encapsulated in the groove 2 can refer to the following description. The groove 2 is adapted to the chip 10, specifically referring to that the chip 10 can be embedded in the groove 2. In one embodiment of the utility model, the groove 2 is rectangular, and two rectangular grooves are arranged side by side on the PCB substrate 1, and a rectangular chip is encapsulated in each rectangular groove. In specific implementation, the number, shape and arrangement of the grooves 2 on the PCB substrate 1 can be selected according to actual packaging requirements.

[0046] The first flexible PCB film 100 and the second flexible PCB film 200 can be suspended and arranged on the front side of the PCB substrate 1. When any two PCB substrates 1 in the PCB substrate group are electrically connected through the second flexible PCB film 200, one of the two PCB substrates 1 connected by the second flexible PCB film 200 is defined as the first PCB substrate, and the other of the two PCB substrates 1 is defined as the second PCB substrate.

[0047] Taking the first PCB substrate as an example, the connection method between the second flexible PCB film 200 and the PCB substrate 1 is explained. When the first PCB substrate has a first flexible PCB film 100, the first flexible PCB film 100 is connected to the second flexible PCB film 200, and the first flexible PCB film 100 and the second flexible PCB film 200 are electrically connected through the internal leads of the flexible PCB film; when the first PCB substrate does not have the first flexible PCB film 100, the second flexible PCB film 200 is directly electrically connected to the chip 10 packaged on the PCB substrate 1.

[0048] The specific manner in which the chip 10 packaged on the same PCB substrate 1 is electrically connected through the first flexible PCB film 100, and the specific manner in which the two PCB substrates 1 are electrically connected through the second flexible PCB film 200 can be referred to the following description.

[0049] In one embodiment of the present invention, the first flexible PCB film 100 is connected to the corresponding second flexible PCB film 200 in a "T" shape, that is, the first flexible PCB film 100 and the connected second flexible PCB film 200 are perpendicular to each other along the length direction. In specific implementation, the connection form of the first flexible PCB film 100 and the corresponding second flexible PCB film 200 can be selected according to actual conditions.

[0050] The high-reliability PCB packaging structure provided by the utility model does not need to use multiple fixtures during packaging operations, avoids redundant fixture design, and simplifies the packaging process. In addition, the packaging structure is flexible and changeable, reduces the packaging volume while reducing layout limitations, and can adapt to a variety of packaging solutions.

[0051] In addition, the utility model replaces the traditional aluminum wire bonding method by routing wires inside the flexible PCB film, effectively avoiding the fracture failure of the aluminum wire bonding point and improving the reliability of the packaging structure and the integration of the packaging.

[0052] Furthermore, the PCB substrate 1 includes a first dielectric layer 4, a second dielectric layer 6 and a metal layer 5, and the metal layer 5 is located between the first dielectric layer 4 and the second dielectric layer 6;

[0053] For any groove 2 on the PCB substrate 1, the bottom of the groove 2 corresponds to the metal layer 5;

[0054] A soldering piece 3 is disposed in the groove 2 . The soldering piece 3 is in contact with the metal layer 5 . The chip 10 packaged in the groove 2 is soldered to the metal layer 5 via the soldering piece 3 .

[0055] Specifically, the first dielectric layer 4 and the second dielectric layer 6 may be made of the same material, the material of the metal layer 5 may be Cu, and the metal layer 5 is located between the first dielectric layer 4 and the second dielectric layer 6 and is in contact with the first dielectric layer 4 and the second dielectric layer 6. In specific implementation, the materials of the first dielectric layer 4, the second dielectric layer 6 and the metal layer 5 may be selected according to actual conditions.

[0056] The chip 10 includes a front side and a back side corresponding to the front side. When the chip 10 is an integrated chip of a power device, a metal electrode is usually provided on the back side of the chip 10. In order to electrically connect the metal electrode on the back side of the chip 10 with the metal layer 5, so that when at least two chips 10 are included on the same PCB substrate 1, the back side metal electrodes of the multiple chips 10 provided on the same PCB substrate 1 are electrically connected to each other, the bottom of the groove 2 needs to correspond to the metal layer 5, that is, the groove 2 needs to extend vertically downward along the surface of the first dielectric layer 4, penetrate the first dielectric layer 4 and use the metal layer 5 to form the bottom of the groove 2, and the surface of the first dielectric layer 4 is the front side of the PCB substrate 1.

[0057] In one embodiment of the present invention, in order to electrically connect the metal electrode on the back of the chip 10 to the metal layer 5, the chip 10 is soldered to the PCB substrate 1 using a soldering process. Figure 1As shown, the soldering sheet 3 is laid on the bottom of the groove 2 and covers the bottom of the groove 2, and the back of the chip 10 is soldered to the metal layer 5 through the soldering sheet 3. In specific implementation, the soldering process can be selected according to actual conditions to meet the packaging requirements of the chip 10.

[0058] Furthermore, the depth of the groove 2 on the PCB substrate 1 is not less than the cross-sectional thickness of the chip 10 packaged in the corresponding groove 2 .

[0059] Specifically, in order to ensure the stability of chip packaging, the depth of the groove 2 is greater than or equal to the cross-sectional thickness of the chip 10 packaged in the corresponding groove 2. Figure 1 As shown, ignoring the thickness of the solder sheet 3 , in this embodiment, the depth of the groove 2 is equal to the cross-sectional thickness of the chip 10 packaged in the groove 2 , and the front side of the chip 10 is flush with the notch of the groove 2 .

[0060] Preferably, the groove depth of the groove 2 is greater than the cross-sectional thickness of the chip 10 encapsulated in the groove 2. When the groove depth of the groove 2 is greater than the cross-sectional thickness of the chip 10 encapsulated in the groove 2, the front side of the chip 10 is lower than the notch of the groove 2. At this time, the front side of the chip 10 can be sealed with glue to further enhance the reliability and stability of the chip 10 packaging, and the effect of the sealing treatment on the heat dissipation of the chip 10 can be ignored.

[0061] Furthermore, the chip 10 includes an IGBT chip. When the chip 10 is an IGBT chip, the front side of the chip 10 includes an emitter pad group. The emitter pad group includes a plurality of emitter pads 11 . Adjacent emitter pads 11 are insulated and isolated by a first trench 13 .

[0062] In one embodiment of the utility model, the emitter welding area group of the IGBT chip includes four emitter welding areas 11, that is, the emitter of the IGBT chip is divided into four areas, such as Figure 2 As shown, four emitter welding regions 11 are arranged in parallel on the front side of the IGBT chip, and adjacent emitter welding regions 11 among the four emitter welding regions 11 are insulated and isolated by the first trench 13 .

[0063] Furthermore, the first flexible PCB film 100 includes a plurality of metal areas 101 and a plurality of flexible areas 102 connecting adjacent metal areas 101 , and connecting leads 103 for realizing electrical connection between adjacent metal areas 101 are arranged in the flexible areas 102 .

[0064] like Figure 2As shown, two adjacent metal areas 101 are connected by a flexible area 102 so that the first flexible PCB film 100 is connected into a whole. In one embodiment of the utility model, the first flexible PCB film 100 formed by connecting a plurality of metal areas 101 and a plurality of flexible areas 102 in accordance with the above connection method is rectangular.

[0065] Furthermore, the emitter pads 101 in the emitter pad group are connected to the metal areas 101 in the first flexible PCB film 100 in a one-to-one correspondence, and the flexible areas 102 connecting the adjacent metal areas 101 are suspended on the front side of the IGBT chip.

[0066] Specifically, the metal area 101 in the first flexible PCB film 100 is welded on the corresponding emitter welding area 101. The number and distribution of the metal areas 101 in the first flexible PCB film 100 can be set according to the number of IGBT chips in the PCB substrate 1 and the distribution of the emitter welding area 11 in the emitter welding area group of the IGBT chip, that is, the number of metal areas 101 is equal to the number of emitter welding areas 11, the area of ​​the metal area 101 is not larger than the area of ​​the emitter welding area 11, and the spacing between adjacent metal areas 101 is not smaller than the spacing between adjacent emitter welding areas 11, so that the emitter welding areas 101 in the emitter welding area group are connected one-to-one with the metal areas 101 in the first flexible PCB film 100.

[0067] like Figure 2 As shown, in this embodiment, two IGBT chips are arranged on a PCB substrate 1, and each IGBT chip includes four emitter welding areas 101. Therefore, in this embodiment, eight metal areas 101 are arranged in the first flexible PCB film 100 for realizing electrical connection between the two IGBT chips, and the area of ​​the metal area 101 and the spacing between adjacent metal areas 101 are adapted to the distribution mode of the emitter welding area 11.

[0068] The flexible area 102 connecting the adjacent metal areas 101 in the first flexible PCB film 100 is suspended on the front of the IGBT chip, and because the flexible area 102 has a bendable property, on the cross section of the PCB substrate 1, the flexible area 102 connecting the adjacent metal areas 101 is suspended in an arc shape on the front of the IGBT chip. Figure 5 As shown in FIG. 1 , in the cross section of an IGBT chip, the first flexible PCB film 100 is wavy on the front of the IGBT chip. In addition, each flexible area 102 is provided with a connecting lead 103 that electrically connects the adjacent metal areas 101. The connecting lead is not Figure 5 Shown in.

[0069] Furthermore, the front side of the IGBT chip further includes a gate electrode welding area 12, and the gate electrode welding area 12 is insulated and isolated from the emitter electrode welding area 11 by a second channel 14;

[0070] The gate pad is connected to a gate drive circuit disposed in the third flexible PCB film.

[0071] Specifically, the distribution of the gate electrode welding area 12 and the emitter electrode welding area 11 on the front side of the IGBT chip is consistent with the prior art. Generally, the gate electrode welding area 12 can be Figure 4 The gate lead 9 shown is connected to the gate drive circuit to control the working state of the IGBT chip. The connection between the gate lead 9 and the gate pad 12 is not shown. Figure 4 As shown in FIG. 1 , the gate drive circuit can adopt a common circuit form used by those skilled in the art.

[0072] However, in order to further improve the reliability and integration of the package, preferably, the gate lead 9 is replaced by a third flexible PCB film, and the gate drive circuit is integrated into the third flexible PCB film. The specific form of the third flexible PCB film can be selected according to actual conditions to meet the electrical connection between the gate welding area 12 and the gate drive circuit.

[0073] Further, the second flexible PCB film 200 includes a plurality of main circuits, and any main circuit includes a filtering unit;

[0074] The filtering unit includes a capacitor C1, an inductor L1 and an inductor L2, and one end of the inductor L1 is connected to one end of the inductor L2 through a first lead 211;

[0075] One end of the capacitor C1 is connected to one end of the inductor L1 and one end of the inductor L2 through a second lead 212 , and the other end of the capacitor C1 is grounded through a ground lead 215 .

[0076] Specifically, several filter units in several main lines can adopt the same form, and the equivalent circuit of the filter unit is as follows: Figure 3 As shown, the filtering unit is used to filter out useless noise and interference. In specific implementation, the form of the filtering unit can be selected according to actual filtering requirements.

[0077] Furthermore, the main circuit further includes a first pad 201, a second pad 202, a third pad 203, a first pin 221 and a ground pin 222;

[0078] The second pad 202 is located between the first pad 201 and the third pad 203 , the inductor L1 is welded on the first pad 201 , the capacitor C1 is welded on the second pad 202 , and the inductor L2 is welded on the third pad 203 ;

[0079] One end of the inductor L1 is connected to the first pin 221 through the third lead 213 , one end of the capacitor C1 is connected to the ground pin 222 through the ground lead 215 , and one end of the inductor L2 is connected to the first flexible PCB film 100 through the fourth lead 214 .

[0080] Figure 2 Only one main circuit in the second flexible PCB film 200 is shown. Figure 2 As shown, in this embodiment, the first pad 201, the second pad 202 and the third pad 203 each include two parallel square pads, and each square pad is provided with a pad frame line in a direction away from the other square pad. Among them, the two square pads in the first pad 201 and the third pad 203 are parallel along a first direction, the first direction is parallel to the setting direction of the first flexible PCB film 100, and the square pads in the second pad 202 are parallel along a second direction, and the second direction is perpendicular to the first direction.

[0081] In any main circuit, the two ends of the inductor L1 are respectively welded to two square pads in the first pad 201 , the two ends of the capacitor C1 are respectively welded to two square pads in the second pad 202 , and the two ends of the inductor L2 are respectively welded to two square pads in the third pad 203 .

[0082] One end of the third lead 213 is welded to the first pin 221, and the other end of the third lead 213 is welded to the first square pad in the first pad 201. One end of the first lead 211 is welded to the second square pad in the first pad 201, and the other end of the first lead 211 is welded to the first square pad of the third pad 203. One end of the second lead 212 is welded to the first square pad of the second pad 202, and the other end of the second lead 212 is connected to the first lead 211. One end of the grounding lead 215 is welded to the second square pad of the second pad 202, and the other end of the grounding lead 215 is welded to the grounding pin 222. One end of the fourth lead 214 is welded to the second square pad of the third pad 203, and the other end of the fourth lead 214 is connected to a connecting lead 103 in the first flexible PCB film 100.

[0083] Furthermore, the material used for the first lead 211 , the second lead 212 , the third lead 213 , the fourth lead 214 and the ground lead 215 includes Au.

[0084] Specifically, the material of the metal area 101 in the first flexible PCB film 100 can also be Au. Using Au as the conductive metal material of the first flexible PCB film 100 and the second flexible PCB film 200 can ensure the flow capacity of the first flexible PCB film 100 and the second flexible PCB film 200 and improve the reliability of the package. In specific implementation, the conductive metal material used in the first flexible PCB film 100 and the second flexible PCB film 200 can be selected according to actual conditions.

[0085] Furthermore, a plurality of heat dissipation holes 7 and a plurality of positioning holes 8 are provided on the PCB substrate 1 .

[0086] like Figure 4 As shown, in this embodiment, a circular positioning hole 8 is provided at each of the four corners of the PCB substrate 1, and the positioning hole 8 is used as a process reference for the PCB substrate 1. The heat dissipation holes 7 are used for heat dissipation of the PCB substrate 1. In this embodiment, the heat dissipation holes 7 are all circular, and are located above and below the chip 10. Figure 4 The x-axis direction shown in FIG is equidistantly arranged in two rows, and the number of the two rows of heat dissipation holes 7 is the same. Generally, the diameter of the heat dissipation hole 7 is smaller than the diameter of the positioning hole 8, and the heat dissipation hole 7 and the positioning hole 8 penetrate the first dielectric layer 4, the metal layer 5 and the second dielectric layer 6. In specific implementation, the number and distribution of the positioning holes 8 and the heat dissipation holes 7 can be selected according to actual needs.

[0087] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

[0088] In the description of the present invention, the terms "front", "rear", "left", "right", "up", "down", "high", "low", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

Claims

1. A high reliability PCB packaging structure, characterized in that: It includes a PCB substrate group, wherein the PCB substrate group includes a plurality of PCB substrates; The PCB substrate is provided with a plurality of grooves, each of which is encapsulated with a chip, and the grooves are adapted to the chip encapsulated in the grooves; When at least two chips are packaged on the same PCB substrate, the chips packaged on the same PCB substrate are electrically connected through the first flexible PCB film; When the PCB substrate group includes at least two PCB substrates, any two PCB substrates in the PCB substrate group are electrically connected through the second flexible PCB film; The second flexible PCB film is connected to the connected PCB substrate via the first flexible PCB film or chip.

2. The high reliability PCB packaging structure according to claim 1, characterized in that: The PCB substrate comprises a first dielectric layer, a second dielectric layer and a metal layer, wherein the metal layer is located between the first dielectric layer and the second dielectric layer; For any groove on the PCB substrate, the bottom of the groove corresponds to the metal layer; A welding piece is arranged in the groove, the welding piece is in contact with the metal layer, and the chip packaged in the groove is welded to the metal layer through the welding piece.

3. The high reliability PCB packaging structure according to claim 1, characterized in that: The second flexible PCB film includes a plurality of main circuits, and any main circuit includes a filtering unit; The filtering unit includes a capacitor C1, an inductor L1 and an inductor L2, and one end of the inductor L1 is connected to one end of the inductor L2 through a first lead; One end of the capacitor C1 is connected to one end of the inductor L1 and one end of the inductor L2 through a second lead, and the other end of the capacitor C1 is grounded through a ground lead.

4. The high reliability PCB packaging structure according to claim 3, characterized in that: The main circuit also includes a first pad, a second pad, a third pad, a first pin and a ground pin; The second pad is located between the first pad and the third pad, the inductor L1 is welded on the first pad, the capacitor C1 is welded on the second pad, and the inductor L2 is welded on the third pad; One end of the inductor L1 is connected to the first pin through a third lead, one end of the capacitor C1 is connected to the ground pin through a ground lead, and one end of the inductor L2 is connected to the first flexible PCB film through a fourth lead.

5. The high reliability PCB packaging structure according to claim 1, characterized in that: The first flexible PCB film includes a plurality of metal areas and a plurality of flexible areas connecting adjacent metal areas, and connecting leads for realizing electrical connection between adjacent metal areas are arranged in the flexible areas.

6. The high reliability PCB packaging structure according to claim 1, characterized in that: The chip comprises an IGBT chip, and the IGBT chip comprises a front side and a back side corresponding to the front side; The front side of the IGBT chip includes an emitter welding area group, the emitter welding area group includes a plurality of emitter welding areas, and adjacent emitter welding areas are insulated and isolated by a first trench; The emitter pads in the emitter pad group are connected to the metal pads in the first flexible PCB film in a one-to-one correspondence, and the flexible pads connecting the adjacent metal pads are suspended on the front side of the IGBT chip.

7. The high reliability PCB packaging structure according to claim 6, characterized in that: The front side of the IGBT chip also includes a gate electrode welding area, and the gate electrode welding area is insulated and isolated from the emitter electrode welding area by a second channel; The gate pad is connected to a gate drive circuit disposed in the third flexible PCB film.

8. The high reliability PCB packaging structure according to claim 1, characterized in that: The PCB substrate is provided with a plurality of heat dissipation holes and a plurality of positioning holes.

9. The high reliability PCB packaging structure according to any one of claims 1 to 8, characterized in that: The depth of the groove on the PCB substrate is not less than the cross-sectional thickness of the chip packaged in the corresponding groove.

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