Power semiconductor module and method for manufacturing a power semiconductor module
By using a metal carrier unit connected in parallel with the substrate in the circuit board structure, the problems of unstable electrical connection and poor heat dissipation of power semiconductor modules in the circuit board structure are solved, and better electrical connection, heat dissipation and current path optimization are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SCHWEIZER ELECTRONIC AG(DE)
- Filing Date
- 2026-01-08
- Publication Date
- 2026-07-10
AI Technical Summary
In the prior art, when power semiconductor modules are connected in parallel in a circuit board structure, there are problems such as unstable electrical connection, poor heat dissipation, and unoptimized current path.
The drain terminal of the power semiconductor is connected to the carrier unit made of metal, and then connected in parallel to the empty part of the metal substrate. Stable electrical connection is achieved by means of laser welding or copper ball pressing, eliminating the need for a micropore layer to improve heat dissipation and optimize the current path.
Stable electrical connection of power semiconductor modules in circuit board structure was achieved, heat dissipation performance and current path were improved, current carrying capacity and insulation spacing were increased, inductance was reduced, and electrical design was optimized.
Smart Images
Figure CN122373828A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a power semiconductor module for embedding in a circuit board structure and a method for manufacturing a power semiconductor module. Background Technology
[0002] Power semiconductor modules are used particularly in high-efficiency switching power supplies to convert electrical energy into different AC and DC voltage levels. These switching power converters enable complex functions in fields such as wireless charging, mobile radio, renewable energy, and smart motors across all sectors.
[0003] To connect multiple power semiconductors in parallel, it is known to connect the power semiconductors to a conductive plane, i.e., a substrate made of metal. The substrate thus assembled can then be incorporated into a circuit board structure. Alternatively, one (or more) circuit board layers can be assembled, and then conductive contacts can be made between the layers above and below them. Summary of the Invention
[0004] Based on this, the present invention provides a power semiconductor module having the features of the present invention, a method for manufacturing a power semiconductor module having the features of the present invention, and a circuit board having the features of the present invention.
[0005] This invention is based on the understanding that power semiconductors are disposed on a carrier unit made of metal, such that the terminals, particularly the drain terminals, of the power semiconductors are connected to the carrier unit. The carrier unit thus assembled is a structural element that can be incorporated into a corresponding empty space in a metal substrate. If multiple such carrier units are incorporated into corresponding empty spaces in a metal substrate, a device composed of power semiconductors connected in parallel is generated. The power semiconductor module can be integrated into a circuit board structure.
[0006] Therefore, according to the present invention, a power semiconductor module for embedding in a circuit board structure is provided, the power semiconductor module comprising a substrate made of metal and a plurality of power semiconductors connected in parallel. Each power semiconductor is disposed on a carrier unit made of metal, such that the drain terminal of the power semiconductor is connected to the disposed carrier unit made of metal. Furthermore, each carrier unit is conductively disposed in a disposed void in the substrate.
[0007] The present invention opens up the possibility of manufacturing standardized carrier units equipped with power semiconductors and subsequently placed in a conductive substrate having provided gaps that match the standardized dimensions of the carrier units.
[0008] Further advantages and design solutions of the present invention are derived from the specification and drawings.
[0009] It goes without saying that the features mentioned above and further described below can be used not only in the combinations given, but also in other combinations or individually, without departing from the scope of the invention.
[0010] The present invention is illustrated schematically by means of one embodiment in the accompanying drawings and is described in detail below with reference to the drawings. Attached Figure Description
[0011] Figure 1 A top view of the power semiconductor module according to the present invention is shown in a highly schematic diagram.
[0012] Figure 2 A photograph showing a top view of a power semiconductor module according to the present invention.
[0013] Figure 3 A highly schematic side sectional view shows a circuit board structure having a power semiconductor module according to the invention.
[0014] Figure 4 Showing according to Figure 3 A photograph of a top view of a circuit board with prominent connector tabs.
[0015] Figure 5 A photograph showing a top view of a carrier unit placed in a substrate by means of spot laser welding.
[0016] Figure 6 A highly schematic side sectional view shows the device for making a connection by means of copper ball clamping.
[0017] Figure 7 A perspective view of a circuit board with a cross-sectional window for visualizing the embedded power semiconductor module is shown. Detailed Implementation
[0018] The same and similar features shown in the various figures are indicated by the same reference numerals.
[0019] Figure 1 A top view of the power semiconductor module 10 according to the present invention is shown in a highly schematic diagram.
[0020] According to the present invention, the power semiconductor module 10 includes a substrate 20, which is made of metal, particularly copper. The substrate 20 is substantially rectangular, but other shapes are also conceivable and feasible in practice. Therefore, it is particularly feasible for the substrate 20 to have protruding tabs 24 that extend from the circuit board structure when the power semiconductor module is embedded in the circuit board structure and are used for connection to a busbar / bus (see also...). Figure 3 and Figure 4 ).
[0021] The substrate 20 has a plurality of open portions 22. In the illustrated embodiment, the substrate 20 has a total of six open portions 22, which are arranged in two rows of three open portions each. The sketch shown is for illustrative purposes only, and substrates with more or fewer open portions are of course feasible.
[0022] The blank space 22 can have a basic square shape (planar profile) as shown, but a different planar profile is also possible.
[0023] The void 22 can be through-hole, that is, extending through the entire thickness d20 of the substrate 20 (see also...). Figure 3 Alternatively, the void may also extend only within a portion of the thickness d20 of the substrate 20.
[0024] The empty space 22 can be introduced into the metal substrate 20 by milling, stamping or any other suitable process.
[0025] According to the present invention, a carrier unit 30 is placed in the empty portion 22 of the substrate 20, and the carrier unit is respectively equipped with a power semiconductor 32 (see also) Figure 2 According to the present invention, the carrier unit is made of metal, for example, copper. Figure 1 The illustration shows two carrier units 30, more precisely, from the observer's perspective, on the far left and far right of the top row. Due to the highly schematic illustration, the power semiconductors 32 mounted on the carrier units 30 are... Figure 1 The figure is not shown.
[0026] Each carrier unit 30 is assembled using a power semiconductor 32, such as a MOSFET chip, as described above, such that the drain terminal of the power semiconductor is connected to the metal material of the carrier unit. The source terminal and gate terminal of the power semiconductor are located on their upper side away from the carrier unit.
[0027] In this manner, the drain potential of the inserted carrier unit 30 is connected to all other carrier units inserted into the substrate 20 via the metal substrate 20.
[0028] To ensure that the carrier unit 30 can be well-fitted and, in particular, well-conducted, placed into the substrate 20, the recess 22 of the substrate 20 is coordinated with the carrier unit 30. Therefore, the recess 22 of the substrate 20 can be precisely configured to accommodate the carrier unit 30. This means that the recess 22 corresponds precisely to the carrier unit 30 in shape and size, allowing the carrier unit 30 to be precisely placed into the recess 22 without any noticeable gap.
[0029] If the carrier unit 30 is constructed in a square shape, for example as shown, and each has a side length of 11 mm, this would mean that the corresponding empty portion 22 is designed with an internal dimension of 11.2 mm ± 0.05 mm. The dimensional description is highly exemplary and is intended only to provide reference for those skilled in the art regarding the term "precise fit." Other geometric planar contours and dimensions are determined by estimations made by those skilled in the art.
[0030] The thickness d30 of the carrier unit 30 preferably corresponds to the thickness d22 of the void 22 in the substrate 20. Therefore, in the case of the void 22 penetrating through the substrate 20, the thickness d30 of the carrier unit 30 corresponds to the thickness d20 of the substrate 20 (see also...). Figure 3 The thickness d20 of the substrate 20 can be between 1 mm and 2 mm. The thickness of the substrate is preferably between 1.1 mm and 1.4 mm, and more preferably between 1.2 mm and 1.3 mm.
[0031] As from Figure 3 As can be seen, the carrier unit 30 may have a surface recess 34 into which the power semiconductor 32 can be placed during assembly. As shown, the depth of the recess advantageously corresponds to the thickness d32 of the power semiconductor 32 to be placed. In this case, the thickness d30 of the carrier unit 30 corresponds to the thickness d20 of the substrate 20. Alternatively, the power semiconductor 32 may be placed on the carrier unit 30 without a surface recess; in this case, the sum of the thickness d30 of the carrier unit 30 and the thickness d32 of the power semiconductor 32 corresponds to the thickness d20 of the substrate 20.
[0032] exist Figure 1 In the illustration, the carrier unit 30, shown in the upper left corner, is inserted only into the void 22. Various methods are provided to establish a durable connection between the inserted carrier unit and the substrate. For cases requiring particularly high fitting precision, i.e., where the external dimensions of the carrier unit and the internal dimensions of the void have only small deviations, the carrier unit can be pressed or pressed into the void, for example. Furthermore, metal joining methods, such as laser welding, are provided. Laser welding can be performed as described in [reference to...]. Figure 1The welding is performed in a circumferential manner, as shown in the upper right of the carrier unit (see circumferential weld 12). Alternatively, spot welding, such as spot welding in the corner regions of carrier unit 30, is also feasible (see...). Figure 5 , laser welding part 14).
[0033] In addition, a so-called back stamping is provided, in which the shape of the carrier unit is punched out from the base 20, and the assembled carrier unit 30 is pressed into the punched area in the same process. Figure 3 A side sectional view shows a circuit board structure 100 with an embedded power semiconductor module 10 according to the invention.
[0034] The power semiconductor module 10 is disposed in the plane of the inner layer 110 of the circuit board structure 100. The inner layer 110 is made of a common electrically insulating inner layer material, which may, as shown, have copper layers 112 on the upper and lower sides.
[0035] The circuit board structure 100 is constructed in a manner known per se, in which the power semiconductor module 10 is placed into a milled area of the inner layer 110. Multiple power semiconductor modules can be placed into a single inner layer. Therefore, an insulation spacing of several millimeters can be achieved between the various phase branches and relative to the DC positive terminal (DC+).
[0036] Subsequently, the inner layer 110 and the power semiconductor module 10 are covered with the first upper and lower prepreg layers 114 and copper foil 116, and then lamination is performed. Cavities are filled by liquefied prepreg generated during lamination, such as the cavities between the power semiconductor module and the inner layer, and in the cavities within the recesses 34 of the carrier unit 30 (the gap between the power semiconductor 32 and the wall of the recess 34). The copper foil 116 can then be further constructed using electroplated copper. As can be seen from the figures, connections (vias) to the power semiconductor can be formed from the copper layer.
[0037] The additional prepreg layer 118 and copper foil 120 can follow in known ways and methods as shown to form another conductor plane. As also shown, the upper metal layer 120 can be covered with a solder resist layer 122.
[0038] On the underside of the circuit board structure 100, the cooling body 126 can also be connected in a planar manner by means of a suitable material layer 124 (e.g., solder layer or TIM (thermal interface material)) in a manner and method known per se.
[0039] Therefore, instead of assembling the embedded components (power semiconductors) in a circuit board layer and making conductive contact with the layers above and below it as previously done in the prior art, the present invention introduces the power semiconductor module into an inner layer having substantially the same thickness as the circuit board, so that no additional internal assembly layer is required in the circuit board structure.
[0040] Figure 3 The power semiconductor module 10 has protruding connection tabs 24 as previously described, which protrude from the circuit board structure 100 after its construction is complete. This combines Figure 4 The illustration is explained. Figure 4 A photograph of a circuit board LP is shown from top view. On the right side of the diagram, from the circuit board, is this type of connecting tab 24 used for making contact / soldering (not shown) busbars / buses for high-current lines. Figure 4 The surface of the LP circuit board is partially blackened.
[0041] Figure 7 The circuit board LP is also shown in a three-dimensional top view, which has a sectioned area that allows for observation. Figure 2 The embedded power semiconductor module 10.
[0042] Figure 6 A highly schematic side sectional view shows a device for connection by means of copper ball clamping, as another possibility for connecting carrier unit 30 to substrate 20.
[0043] In copper ball clamping, a copper ball, or a metal ball made of a sufficiently soft material suitable for clamping, is inserted or placed into a hole introduced in the transition region between the substrate 20 and the inserted carrier unit 30 for the aforementioned purpose, so that it can be subsequently pressed into the hole under deformation by means of two clamping tools (or one clamping tool and one mating tool). If this is performed simultaneously at suitable opposing locations along the circumference of the carrier unit, a durable and conductive connection is created between the carrier unit and the substrate.
[0044] Figure 6To illustrate the process schematically, a section of the substrate 20 and a section of the carrier unit 30 with the same thickness are shown. In the transition region between the carrier unit and the substrate, a through-hole 40 is introduced perpendicular to an extending plane of the substrate 20. A metal ball 42, particularly a copper ball, is placed into the hole 40. To press the copper ball 42 in place, a punch-shaped upper pressing tool 44 and a lower pressing tool 46 are provided. Through the relative movement of the two pressing tools 44 and 46 toward the substrate 20, the copper ball is pressed into the hole 40, whereby the copper ball deforms such that it largely fills the cavity of the hole 40 after the pressing process is complete. The diameter of the metal ball 42 should be greater than the thickness d20 of the substrate 20, i.e., the depth of the hole 40 to be implemented. The diameter of the hole 40 can be less than, greater than, or equal to the diameter of the ball.
[0045] By means of the power semiconductor module according to the invention, better electrical connection of the drain potential of the power semiconductors can be achieved when embedded in a circuit board structure, especially when they are connected in parallel. Improved heat dissipation is also achieved by eliminating the need for a microvia layer. Higher insulation spacing between the respective phase output terminals can be achieved because one or more substrates are introduced into the open space of the inner layer of the circuit board. Furthermore, improvements in current carrying capacity and heat dissipation can be determined compared to other embedding technologies because the lateral contact between the carrier unit and the substrate allows direct connection, for example, of copper layers thicker than 400 µm, and heat can be dissipated laterally with high conductivity. Finally, the application of the power semiconductor module according to the invention results in a low-inductance structure because the semiconductor components on the carrier unit can be introduced into the same workpiece not only upwards but also downwards. This enables new current paths for improved electrical design; in particular, the lateral contact enables shorter current paths than those via contacts of different planes in the layer structure.
Claims
1. A power semiconductor module (10) for embedding in a circuit board structure (100), the power semiconductor module having: A metal substrate (20) and at least one power semiconductor (32). The at least one power semiconductor (32) is disposed on the metal carrier unit (30) such that the terminals, particularly the drain terminals, of the at least one power semiconductor (32) are connected to the carrier unit (30). The carrier unit (30) is electrically disposed in the empty portion (22) provided in the substrate (20).
2. A power semiconductor module (10) for embedding in a circuit board structure (100), the power semiconductor module having: A metal substrate (20) and multiple power semiconductors (32) connected in parallel. Each of the power semiconductors (32) is disposed on a carrier unit (30) made of metal, such that the terminals, particularly the drain terminals, of each power semiconductor (32) are connected to the carrier unit (30) to which it is disposed, and Each carrier unit (30) is electrically disposed in the empty portion (22) provided in the substrate (20).
3. The power semiconductor module (10) according to claim 1 or 2, wherein the at least one void (22) of the substrate (20) is precisely configured to accommodate the at least one carrier unit (30).
4. The power semiconductor module (10) according to any one of claims 1 to 3, wherein the thickness (d30) of one or more of the carrier units (30) substantially corresponds to the thickness (d22) of the disposed void (22) of the substrate (20), and / or the planar profile shape of one or more of the carrier units (30) substantially corresponds to the planar profile shape of the disposed void (22) of the substrate (20).
5. The power semiconductor module (10) according to any one of claims 1 to 4, wherein the at least one power semiconductor (32) is disposed such that it is fitted into the recess (34) of the disposed carrier unit (30), in particular flush with the surface.
6. The power semiconductor module (10) according to any one of the preceding claims, wherein one or more of the carrier units (30) are introduced into the provided void (22) of the substrate (20) by laser welding, pressing, crimping or other metal connection methods.
7. The power semiconductor module (10) according to any one of the preceding claims, wherein one or more blank portions (22) of the substrate (20) are produced by milling, stamping or similar processes.
8. A method for manufacturing a power semiconductor module (10), the method comprising the following steps: - At least one carrier unit (30) made of metal is assembled using a power semiconductor (32), such that the terminals, particularly the drain terminals, of the power semiconductor (32) are connected to the carrier unit (30). - Provide a metal substrate (20) having at least one void (22). - Insert at least one assembled carrier unit (30) into the provided empty space (22).
9. The method according to claim 7, wherein, prior to assembly, a surface recess (34) is formed in the carrier unit (30), and the power semiconductor (32) is placed in the surface recess.
10. The method according to claim 8 or 9, wherein the at least one carrier unit (30) is introduced into the provided void (22) of the substrate (20) by laser welding, pressing, crimping or other metal connection methods, for example by pressing in with a metal ball.
11. The method according to any one of claims 8 to 10, wherein in order to connect the inserted assembled carrier unit (30) to the substrate (20), metal ball clamping is performed, the metal ball clamping comprising the following steps: - Introduce at least one hole (40) in the transition region between the carrier unit (30) and the substrate (20). - Place the metal ball (42) onto or into each of the at least one hole (40). - The metal ball (42) is pressed into the hole (40) by means of a pressing tool (44, 46) while the metal ball (42) is deformed.
12. A circuit board structure (100) or circuit board (LP) having a power semiconductor module (10) embedded therein according to any one of claims 1 to 7.