IGBT package structure

Abstract

An IGBT packaging structure includes a mounting interface, an IGBT module, a positioning cover and a plurality of fasteners. The mounting interface has a plurality of positioning holes and a plurality of fastening holes. The IGBT module includes an insulating frame having a plurality of through holes, and a ceramic substrate and a wafer module sequentially arranged on the mounting interface and accommodated in the insulating frame. The ceramic substrate and the fastening holes and the through holes define a first linear length and a second linear length smaller than the first linear length, respectively. The positioning cover is pre-pressed to cover the IGBT module and has a plurality of positioning columns and a plurality of through holes. Each positioning column penetrates each through hole and is engaged in each positioning hole. Each fastener penetrates each through hole and is fixed in each fastening hole to clamp the IGBT module between the mounting interface and the positioning cover, thereby avoiding the ceramic substrate from being broken when the IGBT module is fixed on the mounting interface and enabling the thermal paste to be evenly spread.

Description

Technical Field

[0001] This utility model relates to the semiconductor field, and more particularly to an IGBT packaging structure. Background Technology

[0002] With the booming development of industries such as automobiles, industrial, energy, and electronics, the demand for various semiconductor components has increased significantly. Among them, Insulated Gate Bipolar Transistors (IGBTs) are widely used in industries such as automobiles and industrial applications. IGBTs mainly consist of a ceramic substrate and multiple silicon wafers mounted on the ceramic substrate. Generally, in order to effectively protect the ceramic substrate and each silicon wafer and ensure that the IGBT can maintain its operating temperature during operation, the ceramic substrate and each silicon wafer are usually housed in an insulating housing. The insulating housing is then secured to a housing or plate so that the ceramic substrate can be attached to a heat sink for heat dissipation.

[0003] However, the mounting holes of conventional IGBT insulating housings are mostly located near the side of the IGBT. Therefore, when multiple bolts are used to fasten the insulating housing, the stress waves generated by each bolt are transmitted to the ceramic substrate, causing cracking or damage. Furthermore, when fastening the bolts, assemblers need to use low torque and low speed, and fasten in multiple stages to avoid damaging the IGBT. This significantly increases assembly time and limits the use of high-strength bolts due to the low torque, resulting in limited fastening force.

[0004] Furthermore, to eliminate gaps and machining tolerances between the heat sink and the ceramic substrate and to increase thermal conductivity, assemblers apply thermal paste between them before installation. To ensure a tight fit between the ceramic substrate and the heat sink using the thermal paste, commercially available conventional insulating housings are typically positioned lower than the bottom surface of the ceramic substrate to ensure sufficient contact between the heat sink and the bottom surface of the ceramic substrate. However, this design often causes the insulating housing to warp after one side is secured, leading to bending stress during subsequent securing of the warped side, which can cause cracking or damage to the ceramic substrate. Current solutions mostly involve using additional fixtures to pre-press the insulating housing before securing it, and reducing torque and speed during securing. However, this not only increases assembly steps and time but also significantly increases production costs.

[0005] In addition to the IGBT being secured by the insulating housing, a circuit board is mounted on top of it to solder to the IGBT's multiple pins to form an electrical connection. To prevent oxidation, rust, dirt, or short circuit damage to the pins due to moisture or dust, the circuit board is coated with a moisture-proof adhesive after soldering. However, since the moisture-proof adhesive cannot be applied to the gap between the bottom of the circuit board and the insulating housing, an additional rubber ring is usually used to protect the exposed parts of the pins between the circuit board and the insulating housing, thus increasing the assembly process and production costs.

[0006] In view of this, the creator has devoted himself to researching and applying theoretical principles to address the shortcomings of the existing technology, and has made every effort to solve the above-mentioned problems, which has become the creator's goal for improvement. Utility Model Content

[0007] The main purpose of this invention is to securely fix the IGBT module to the mounting interface while preventing the ceramic substrate inside the IGBT module from cracking due to assembly stress waves or uneven force. Furthermore, the positioning cover pre-presses the IGBT module onto the mounting interface to ensure that the thermal paste is pressed more evenly, thereby increasing heat dissipation efficiency.

[0008] To achieve the above objectives, this utility model provides an IGBT packaging structure, including a mounting interface, an IGBT module, a positioning cover, and multiple fasteners. The mounting interface has multiple positioning holes and multiple fixing holes, with each positioning hole located between the fixing holes. The IGBT module includes an insulating frame, a ceramic substrate, and a chip module. The insulating frame has multiple through holes. The ceramic substrate and the chip module are sequentially disposed on the mounting interface and housed within the insulating frame. A first straight-line length is defined between the ceramic substrate and any fixing hole, and a second straight-line length is defined between the ceramic substrate and any through hole. The first straight-line length is greater than the second straight-line length. The positioning cover covers the IGBT module and has multiple positioning posts and multiple through holes. Each positioning post passes through each through hole and engages with each positioning hole to pre-press and restrict the IGBT module on the mounting interface. Each fastener passes through each through hole and is fixed within each fixing hole to clamp the IGBT module between the mounting interface and the positioning cover.

[0009] In one embodiment of this utility model, each positioning hole and each fixing hole are located on the same straight line.

[0010] In one embodiment of the present invention, each positioning post is located between each through hole, and each positioning post and each through hole are located on the same straight line.

[0011] In one embodiment of this utility model, each fixing member is a bolt, and each fixing hole is a screw hole.

[0012] In one embodiment of the present invention, each positioning post extends from the positioning outer cover, and each positioning post is hollow and has multiple through slots parallel to its extension direction.

[0013] In one embodiment of the present invention, each positioning post has a plurality of hooks formed at its end.

[0014] In one embodiment of the present invention, the positioning cover further has a limiting groove and a pre-compression plane. The pre-compression plane is located in the limiting groove, and the top of the insulating frame is accommodated in the limiting groove and abuts against the pre-compression plane and is pre-compressed and limited by the positioning cover.

[0015] In one embodiment of this utility model, the limiting groove and the pre-compression plane are located between each positioning post.

[0016] In one embodiment of the present invention, the positioning cover includes a body and a pair of fixing seats, each fixing seat extending in opposite directions from opposite sides of the body, and each fixing seat having at least one positioning post and at least one through hole.

[0017] In one embodiment of the present invention, the positioning cover further includes multiple reinforcing ribs, each reinforcing rib being connected to multiple corners between the main body and each fixed seat.

[0018] The IGBT packaging structure of this invention defines a first straight line length between the ceramic substrate and any fixing hole and between any through hole, and the first straight line length is greater than a second straight line length. The IGBT module is covered by a positioning cover, and each positioning post of the positioning cover passes through the through hole and engages in the positioning hole. Each fixing member passes through the through hole and is fixed in the fixing hole, so that the IGBT module is clamped between the mounting interface and the positioning cover. Therefore, while the IGBT module is firmly fixed on the mounting interface, the pre-compression plane of the positioning cover and each positioning post will generate a pre-compression effect on the IGBT module, thereby avoiding the cracking of the ceramic substrate inside the IGBT module due to stress waves or uneven force, and allowing the thermal paste to spread evenly to increase heat dissipation efficiency. Attached Figure Description

[0019] Figure 1 This is an exploded perspective view of the present invention;

[0020] Figure 2 This is a three-dimensional view of the present invention;

[0021] Figure 3 This is an exploded perspective view of the present invention and the circuit board;

[0022] Figure 4 This is a three-dimensional view of the utility model and the circuit board;

[0023] Figure 5This is a cross-sectional side view of the present invention and the circuit board;

[0024] Figure 6 This is a partial cross-sectional side view of another embodiment of the present invention.

[0025] [Symbol Explanation]

[0026] 10: Installation Interface

[0027] 11: Radiator

[0028] 12: Positioning hole

[0029] 13: Fixing hole

[0030] 20: IGBT Module

[0031] 21: Insulation Frame

[0032] 211: Perforation

[0033] 22: Ceramic substrate

[0034] 221: Ceramic insulation layer

[0035] 222: Copper foil layer

[0036] 23: Chip Module

[0037] 24: Foot Connection

[0038] 30: Positioning Cover

[0039] 301:Ontology

[0040] 302: Fixture

[0041] 303: Reinforcing Ribs

[0042] 31: Limiting groove

[0043] 32: Positioning Post

[0044] 321: Through slot

[0045] 322: Guide cone surface

[0046] 323: Hook

[0047] 33: Through hole

[0048] 34: Preload plane

[0049] 40: Fasteners

[0050] 50: Circuit board

[0051] L1: Length of the first straight line

[0052] L2: Length of the second line Detailed Implementation

[0053] In the description of this utility model, it should be understood that the terms "front side", "rear side", "left side", "right side", "front end", "rear end", "end", "longitudinal", "lateral", "vertical", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting conditions of this utility model.

[0054] As used herein, terms such as “first,” “second,” “third,” “fourth,” and “fifth” describe various elements, components, regions, hierarchies, and / or parts, which should not be limited by these terms. These terms are used only to distinguish one element, component, region, hierarchy, or part from another. Unless the context clearly indicates otherwise, the use of terms such as “first,” “second,” “third,” “fourth,” and “fifth” herein does not imply order or sequence.

[0055] Unless otherwise defined, the terms "substantially" and "approximately" are used to describe and narrate small changes. When combined with an event or situation, the term may include the exact moment the event or situation occurred, or an approximate point in time. For example, when combined with a numerical value, the term may include a range of variation less than or equal to ±10% of the value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0056] The detailed description and technical content of this utility model will be explained below with reference to the accompanying drawings. However, the accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this utility model.

[0057] This utility model provides an IGBT packaging structure for securing an Insulated Gate Bipolar Transistor (IGBT). Please refer to [reference needed]. Figures 1 to 2 As shown, the IGBT packaging structure of this utility model mainly includes an installation interface 10, an IGBT module 20, a positioning cover 30, and multiple fasteners 40.

[0058] In this embodiment, the mounting interface 10 is a housing with a heat sink 11. However, this invention is not limited to this. For example, the mounting interface 10 can also be a heat sink, a substrate, a housing, or other forms. The form of the mounting interface 10 can be adjusted according to different needs. The mounting interface 10 has multiple positioning holes 12 and multiple fixing holes 13. In this embodiment, each positioning hole 12 and each fixing hole 13 is formed on the heat sink 11 of the mounting interface 10. However, this invention is not limited to this. Each positioning hole 12 is located between each fixing hole 13. Specifically, in this embodiment, there are two positioning holes 12 and two fixing holes 13, and each positioning hole 12 and each fixing hole 13 are substantially arranged on the same straight line. However, in other embodiments, there can be three or more positioning holes 12 and fixing holes 13. Each positioning hole 12 only needs to be located within the surrounding area of ​​each fixing hole 13. However, it is preferable that each positioning hole 12 and each fixing hole 13 should be symmetrically arranged to ensure stable fixing.

[0059] Please refer to the following: Figure 5As shown, the IGBT module 20 includes an insulating frame 21, a ceramic substrate 22, at least one chip module 23, and multiple pins 24. The ceramic substrate 22 and the chip module 23 are sequentially disposed on the mounting interface 10 to jointly constitute the aforementioned insulated gate bipolar transistor (hereinafter referred to as IGBT), and the IGBT (i.e., the ceramic substrate 22 and the chip module 23) are both housed within the insulating frame 21. In this embodiment, the ceramic substrate 22 and the chip module 23 are sequentially disposed on the heat sink 11 of the mounting interface 10, and a thermal paste (not shown) is applied between the ceramic substrate 22 and the heat sink 11 of the mounting interface 10, thereby enabling effective passive heat dissipation of the IGBT through the thermal paste and the heat sink 11. The ceramic substrate 22 mainly includes a ceramic insulating layer 221 and a pair of copper foil layers 222 respectively bonded to the upper and lower sides of the ceramic insulating layer 221. Specifically, in this embodiment, each copper foil layer 222 is bonded to the top and bottom surfaces of the ceramic insulating layer 221 by direct bond copper (DBC). However, in other embodiments, direct plated copper (DPC) or active metal brazing (AMB) can also be used for bonding. Each pin 24 is electrically connected to the ceramic substrate 22 and the chip module 23, and each pin 24 extends through the insulating frame 21. The insulating frame 21 has multiple through holes 211. A first straight length L1 is defined between the ceramic substrate 22 and any fixing hole 13, and a second straight length L2 is defined between the ceramic substrate 22 and any through hole 211. Since each positioning hole 12 is located between each fixing hole 13, the first straight length L1 is greater than the second straight length L2, that is, the length between the ceramic substrate 22 and any fixing hole 13 is longer than the length between the ceramic substrate 22 and any through hole 211.

[0060] In this embodiment, the positioning cover 30 is made of an insulating material such as plastic, but this utility model does not impose many limitations on this, as long as the positioning cover 30 has insulating properties. The positioning cover 30 is a cover for the IGBT module 20. Specifically, the positioning cover 30 has a limiting groove 31, a plurality of positioning posts 32, and a plurality of through holes 33. Each positioning post 32 extends from the bottom of the positioning cover 30 and is located between the through holes 33. Each positioning post 32 passes through the through holes 211 of the insulating frame 21 and engages with the positioning holes 12 of the mounting interface 10, thereby pre-pressurizing and fixing the IGBT module 20 on the mounting interface 10. Specifically, the positioning cover 30 also has a pre-pressurizing plane 34 located in the limiting groove 31. The limiting groove 31 is formed at the bottom of the positioning cover 30 and is located between the positioning posts 32, as is the pre-pressurizing plane 34. The top periphery of the insulating frame 21 is accommodated and locked within the limiting groove 31 and limited by the positioning cover 30. Simultaneously, the top of the insulating frame 21 is pre-pressed and restricted onto the mounting interface 10 by the pre-pressing plane 34 of the positioning cover 30. This allows the IGBT module 20 to be pre-assembled within the positioning cover 30, thus achieving initial positioning for subsequent installation. Each through hole 33 penetrates the positioning cover 30 and corresponds to a fixing hole 13 on the mounting interface 10. In other words, the number of positioning posts 32 and through holes 33 corresponds to the number of positioning holes 12 and fixing holes 13, respectively. That is, in this embodiment, there are two positioning posts 32 and two through holes 33, and each positioning post 32 and each through hole 33 is essentially arranged on the same straight line.

[0061] Each fixing member 40 passes through the through holes 33 of the positioning cover 30, and each fixing member 40 is fixed in the fixing holes 13 of the mounting interface 10 so that the IGBT module 20 is clamped between the mounting interface 10 and the positioning cover 30. In this embodiment, each fixing member 40 is a bolt, and each fixing hole 13 is a screw hole. Each bolt passes through the through hole 33 and is locked in the screw hole to fix the positioning cover 30 to the mounting interface 10. However, this utility model is not limited to the above description. For example, the fixing member 40 can also be a rivet or a pin, and the fixing hole 13 can be a blind hole or a through hole 33. Alternatively, the fixing member 40 and the fixing hole 13 can also be a combination of a hook and a snap hole.

[0062] Therefore, since each positioning hole 12 is located between each fixing hole 13, and the first straight-line length L1 between the ceramic substrate 22 and any fixing hole 13 is greater than the second straight-line length L2 between the ceramic substrate 22 and any through hole 211, when each fixing member 40 passes through the corresponding through hole 33 and is fixed in the corresponding fixing hole 13, the ceramic substrate 22 inside the IGBT module 20 will not be cracked or damaged. More specifically, when the bolts of each fixing member 40 in this embodiment are tightened, the stress wave generated during the tightening process cannot be transmitted to the ceramic substrate 22 due to the long distance, so naturally the ceramic substrate 22 will not be cracked or damaged, and the torque and speed during bolt tightening can also be increased, thereby effectively reducing assembly time. In addition, since the pre-pressing plane 34 of the positioning cover 30 is attached to the top of the insulating frame 21 over a large area, and each positioning post 32 passes through the perforation 211 and engages in the positioning hole 12, the positioning cover 30 pre-presses and fixes the IGBT module 20 to the mounting interface 10. Therefore, it can effectively increase the pressing area of ​​the IGBT module 20, allowing the thermal paste to be evenly pressed and distributed between the ceramic substrate 22 and the heat sink 11 of the mounting interface 10. Furthermore, when the fixing parts 40 fix the positioning cover 30, no additional jig is needed to press the IGBT module 20, thereby effectively simplifying the assembly process and reducing production costs. Compared with the traditional method of relying on only two locking points to lock the insulating frame 21, this method not only increases the pre-pressing effect without the need for jig assistance, but also eliminates the need to reduce torque and speed during locking. It also prevents the IGBT module 20 from tilting to one side, thereby effectively reducing assembly steps, assembly time, and production costs.

[0063] Please refer to the following: Figures 3 to 5 As shown, the IGBT packaging structure of this utility model also includes a circuit board 50. The circuit board 50 is mounted on the mounting interface 10 and abuts against the top of the positioning cover 30. The circuit board 50 is soldered to each pin 24 to form an electrical connection with the IGBT (i.e., the ceramic substrate 22 and the chip module 23) of the IGBT module 20. In this embodiment, the top surface of the circuit board 50 (i.e., the side of the circuit board 50 away from the mounting interface 10) is sprayed with a moisture-proof adhesive (not shown) to protect each pin 24 and solder joint from oxidation, rust, or dirt caused by moisture or dust. It is worth noting that although the bottom surface of the circuit board 50 (i.e. the side of the circuit board 50 facing the mounting interface 10) cannot be coated with moisture-proof adhesive, since the periphery of the top of the insulating frame 21 is accommodated and locked in the limiting groove 31 at the bottom of the positioning cover 30, the pins 24 below the circuit board 50 are surrounded by the positioning cover 30 and will not be exposed. Therefore, the IGBT packaging structure of this utility model does not need to be covered with an additional plastic sleeve for protection, thereby further saving costs and assembly time.

[0064] To further explain, in order to ensure that each positioning post 32 can be securely engaged within its corresponding positioning hole 12, each positioning post 32 in this embodiment is hollow and has multiple through slots 321 parallel to its extension direction, and the outer diameter of each positioning post 32 is slightly larger than the inner diameter of each positioning hole 12. Specifically, each through slot 321 is elongated, and its length is substantially the same as the extension length of the corresponding positioning post 32, and each through slot 321 extends laterally through the corresponding positioning post 32. Thus, when each positioning post 32 passes through its corresponding through hole 211 to its corresponding positioning hole 12, the hollow structure of each positioning post 32 and the through slots 321 provide space for deformation and collapse, allowing the positioning post 32, whose outer diameter is slightly larger than the inner diameter of the positioning hole 12, to be tightly engaged within the positioning hole 12. Furthermore, to facilitate the smooth insertion of each positioning post 32 into its corresponding positioning hole 12, each positioning post 32 in this embodiment has a guide cone surface 322 at its end, but this invention is not limited to this. For example, please see Figure 6 As shown, another embodiment of the present invention is provided, wherein each positioning post 32 has a plurality of hooks 323 at its end, which increases the amount of deformation and collapse toward its axis when each positioning post 32 is inserted into each positioning hole 12, thereby providing a better locking force to securely engage each positioning post 32 in each positioning hole 12.

[0065] See also Figure 1 , Figure 2 and Figure 5 As shown, the positioning cover 30 in this embodiment includes a body 301 and a plurality of fixing seats 302. The bottom of the body 301 has the aforementioned limiting groove 31. In this embodiment, there are two fixing seats 302, each extending in opposite directions from opposite sides of the body 301. However, this invention is not limited to this; for example, there could be four fixing seats 302 extending from the four corners of the body 301. More specifically, each fixing seat 302 extends obliquely from the body 301 towards its opposite sides, so that the positioning cover 30 is suspended when fixed to the mounting interface 10, thereby effectively reducing weight and volume to save production costs. Each fixing seat 302 has at least one positioning post 32 and at least one through hole 33. In this embodiment, each fixing seat 302 has one positioning post 32 and one through hole 33. Furthermore, the positioning cover 30 also includes a plurality of reinforcing ribs 303. Each reinforcing rib 303 is connected at multiple corners between the main body 301 and each fixing seat 302, thereby effectively enhancing the structural strength of both sides of the positioning cover 30.

[0066] The IGBT packaging structure of this utility model defines a first straight length L1 between the ceramic substrate 22 and any fixing hole 13 and between any through hole 211, and the first straight length L1 is greater than the second straight length L2. The positioning cover 30 covers the IGBT module 20, so that each positioning post 32 of the positioning cover 30 passes through each through hole 211 and is engaged in each positioning hole 12. Each fixing member 40 passes through each through hole 33 and is fixed in each fixing hole 13, so that the IGBT module 20 is clamped between the mounting interface 10 and the positioning cover 30. Therefore, while the IGBT module 20 is firmly fixed on the mounting interface 10, the pre-compression plane 34 of the positioning cover 30 and each positioning post 32 are used to generate a pre-compression effect on the IGBT module 20, so as to avoid the ceramic substrate 22 inside the IGBT module 20 from cracking due to stress waves or uneven force, and to allow the thermal paste to spread evenly to increase the heat dissipation efficiency.

[0067] In summary, the foregoing disclosure of this utility model is intended to enable those skilled in the art to clearly understand the technical content of this utility model and implement it accordingly, and is not intended to limit the scope of patent protection of this utility model. In addition, this utility model may have other embodiments not listed. Without departing from the spirit and essence of this utility model, those skilled in the art should be able to devise various corresponding changes and modifications based on this utility model, but all such changes and modifications should fall within the scope of protection of the patent application filed for this utility model.

Claims

1. An IGBT packaging structure, characterized in that, include: An installation interface has multiple positioning holes and multiple fixing holes, with each positioning hole located between each fixing hole; An IGBT module includes an insulating frame, a ceramic substrate, and a chip module. The insulating frame has multiple through holes. The ceramic substrate and the chip module are sequentially disposed on the mounting interface and housed within the insulating frame. A first linear length is defined between the ceramic substrate and any of the fixing holes, and a second linear length is defined between the ceramic substrate and any of the through holes. The first linear length is greater than the second linear length. A positioning cover is provided to enclose the IGBT module. The positioning cover has multiple positioning posts and multiple through holes. Each positioning post passes through a through hole and engages with the positioning hole to pre-pressurize and secure the IGBT module on the mounting interface. Multiple fasteners are respectively threaded through each of the through holes and fixed in each of the fixing holes so that the IGBT module is clamped between the mounting interface and the positioning cover.

2. The IGBT packaging structure according to claim 1, characterized in that, Each positioning hole and each fixing hole are located on the same straight line.

3. The IGBT packaging structure according to claim 1, characterized in that, Each positioning post is located between each through hole, and each positioning post and each through hole are on the same straight line.

4. The IGBT packaging structure according to claim 1, characterized in that, Each of the aforementioned fasteners is a bolt, and each of the aforementioned fixing holes is a screw hole.

5. The IGBT packaging structure according to claim 1, characterized in that, Each positioning post extends from the positioning cover, and each positioning post is hollow and has multiple through slots parallel to its extension direction.

6. The IGBT packaging structure according to claim 5, characterized in that, Each of the positioning posts has multiple hooks formed at its end.

7. The IGBT packaging structure according to claim 1, characterized in that, The positioning cover also has a limiting groove and a pre-compression plane. The pre-compression plane is located in the limiting groove. The top of the insulating frame is accommodated in the limiting groove and abuts against the pre-compression plane and is pre-compressed and limited by the positioning cover.

8. The IGBT packaging structure according to claim 7, characterized in that, The limiting groove and the pre-compression plane are located between each of the positioning posts.

9. The IGBT packaging structure according to claim 1, characterized in that, The positioning cover includes a body and a pair of fixing seats, each fixing seat extending in opposite directions from opposite sides of the body, and each fixing seat having at least one positioning post and at least one through hole.

10. The IGBT packaging structure according to claim 9, characterized in that, The positioning cover also includes multiple reinforcing ribs, each of which is connected to multiple corners between the body and each of the fixing seats.

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