Internally-connected power module using printed circuit board

Abstract

Disclosed is an internally-connected power module using a printed circuit board, comprising: an insulation substrate including a metal layer; a power semiconductor device disposed on the upper surface of the metal layer of the insulation substrate; and a printed circuit board which is disposed on the upper part of the power semiconductor device, and which has a conductive pattern and a conductive via hole that are electrically connected to a terminal of the power semiconductor device and the metal layer on the upper surface of the insulation substrate, wherein, if there is a flow of current, the current is conducted between the power semiconductor device and the metal layer through the conductive pattern and the conductive via hole.

Description

Power module with internal connection structure using printed circuit board

[0001] The present invention relates to a power module, and more particularly, to a power module capable of eliminating wires for internal connection by forming an internal connection structure using a printed circuit board (PCB).

[0002] A power module is a device used to convert direct current into alternating current when driving a motor or compressor in home appliances, hybrid vehicles, electric vehicles, etc.

[0003] Typically, a power module may include a substrate, a power semiconductor element that is a switching element bonded to the substrate, a power lead that supplies power to the power semiconductor element, and a signal lead that provides a control signal to the power semiconductor element.

[0004] Power semiconductor devices within power modules, which are switching elements, generate significant heat due to repeated on / off operations. To facilitate heat dissipation, they are manufactured by bonding them to a substrate such as DBC (Direct Bonded Copper). Furthermore, power leads are electrically connected to the power semiconductor devices via wires (usually made of aluminum (Al)) to enable them to receive and output current from an external source.

[0005] These aluminum wires generate large parasitic inductance, and as their length increases, the current capacity that can flow through them decreases.

[0006] In addition, depending on the pin structure or the shape of the lead frame exposed to the outside of the power module, the aluminum wire is manufactured in a form that has a bent part rather than a straight line, and a structure with such a bent part may cause cracks or wire separation when subjected to severe stress.

[0007] Therefore, in the field of power modules, there is an urgent need for a new electrical connection structure that can conduct current without using current-carrying aluminum wires.

[0008] The matters described as background technology above are only intended to enhance understanding of the background of the present invention, and should not be taken as an admission that they correspond to prior art already known to those skilled in the art.

[0009] Accordingly, the present invention aims to provide a power module having an internal connection structure using a printed circuit board that can provide a new wiring structure for forming a current path within a power module by omitting a wire made of aluminum material through which current flows.

[0010] The problems to be solved by the present invention are not limited to those described above. Other problems and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, those skilled in the art will readily appreciate that the problems and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0011] As a means for solving the above technical problem, the present invention,

[0012] An insulating substrate comprising a metal layer;

[0013] A power semiconductor element disposed on the upper surface of the metal layer of the insulating substrate; and

[0014] A printed circuit board is disposed on top of the power semiconductor element and includes a conductive pattern and a conductive via hole electrically connected to the terminal of the power semiconductor element and the metal layer on the upper surface of the insulating substrate,

[0015] A power module having an internal connection structure using a printed circuit board is provided, characterized in that when a current flow occurs, current is conducted between the power semiconductor element and the metal layer through the conductive pattern and the conductive via hole.

[0016] In an embodiment of the present invention, a concave portion for accommodating the power semiconductor element may be formed on the lower surface of the insulating substrate.

[0017] An embodiment of the present invention further includes a dielectric layer disposed between the metal layer and the printed circuit board, wherein the dielectric layer may include a hollow portion for accommodating the power semiconductor element.

[0018] Embodiments of the present invention may further include active electrical or electronic components or passive electrical or electronic components arranged on the printed circuit board.

[0019] An embodiment of the present invention may further include a mold part that seals the power semiconductor element and the printed circuit board so that the other surface of the insulating substrate on which the power semiconductor element is not arranged is exposed.

[0020] An embodiment of the present invention may further include a lead having one end bonded to the upper surface of the printed circuit board and the other end exposed to the outside of the mold portion to exchange current with the outside.

[0021] According to the power module having an internal connection structure using the above printed circuit board, by replacing the Al material wire used as an electrical connection means for current flow in a conventional power module with a conductive pattern and conductive via hole of the printed circuit board, it is possible to achieve an improvement in rated current and a reduction in parasitic inductance and stray inductance.

[0022] In addition, according to the power module having an internal connection structure using the printed circuit board, the degree of freedom in circuit design is improved by forming electrical connections using conductive patterns and conductive via holes of the printed circuit board, and the production time and production cost can be reduced through process simplification.

[0023] In addition, according to the power module having an internal connection structure using the printed circuit board, additional electrical and electronic components can be placed on the printed circuit board, which is advantageous for integration, and leads for current input / output with the outside can be bonded to the printed circuit board, so cost reduction due to omission of the lead frame, process simplification, and increased design freedom can be expected.

[0024] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0025] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to facilitate a better understanding of the technical idea of ​​the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in the following drawings.

[0026] FIG. 1 is a cross-sectional view of a power module having an internal connection structure using a printed circuit board according to one embodiment of the present invention.

[0027] FIG. 2 is a plan view illustrating an example of a printed circuit board applied to a power module having an internal connection structure using a printed circuit board according to another embodiment of the present invention.

[0028] FIG. 3 is a cross-sectional view of a power module having an internal connection structure using a printed circuit board according to another embodiment of the present invention.

[0029] Hereinafter, a power module having an internal connection structure using a printed circuit board according to various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0030] The specific structural or functional descriptions of the embodiments described below are disclosed for illustrative purposes only and may be modified and implemented in various forms. Accordingly, the embodiments are not limited to the specific disclosed form, and the scope of this specification includes modifications, equivalents, or alternatives that fall within the technical scope.

[0031] Although terms such as "first" or "second" may be used to describe various components, these terms should be interpreted solely to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0032] When it is said that a component is "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but there may also be other components in between.

[0033] Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "has" should be understood to indicate the presence of a described feature, number, step, operation, component, part, or combination thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0034] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0035]

[0036] FIG. 1 is a cross-sectional view of a power module having an internal connection structure using a printed circuit board according to one embodiment of the present invention.

[0037] Referring to FIG. 1, a power module (10) having an internal connection structure using a printed circuit board according to one embodiment of the present invention may be configured to include an insulating substrate (11), one or more power semiconductor elements (12) arranged on an upper surface of the insulating substrate (11), and a printed circuit board (13) arranged on an upper surface of the power semiconductor elements (12).

[0038] In addition, a power module (10) having an internal connection structure using a printed circuit board according to one embodiment of the present invention may further include at least one active or passive electrical and electronic element (14) placed on a printed circuit board (13), a mold part (15) sealing several elements placed on an insulating substrate (11), and a lead (16) extended from the upper surface of the printed circuit board (13) to the outside of the mold part (15).

[0039] FIG. 2 is a plan view illustrating an example of a printed circuit board applied to a power module having an internal connection structure using a printed circuit board according to another embodiment of the present invention.

[0040] Referring to FIGS. 1 and 2, the insulating substrate (11) may be a substrate composed of an insulating layer (112) and metal layers (copper layers) (111, 113) bonded to the upper and lower surfaces of the insulating layer (112), respectively. Such a substrate is referred to in the art as a Direct Bonded Copper (DBC) substrate. Such an insulating substrate can effectively disperse heat generated from a power semiconductor element (12) bonded on the insulating substrate (11) by ensuring a sufficient thickness of the metal layers (111, 113). That is, the insulating substrate (11) is a substrate used for efficient cooling of a power semiconductor element (12) that generates a lot of heat.

[0041] In an embodiment of the present invention, the power semiconductor element (12) may be bonded to the upper surface of the upper metal layer (111) of the insulating substrate (11). The power semiconductor element (12) may be fixedly placed on the insulating substrate by soldering or sintering, which are component bonding processes known in the art.

[0042] The power semiconductor device (12) is a switching semiconductor device for power conversion known in the art and may include an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and / or a diode.

[0043] Recently, SiC (silicon carbide)-based power semiconductor devices, which are gaining popularity, can be manufactured as a single chip by integrating the switching power semiconductor devices, such as IGBTs or power MOSFETs, with diodes. When single-chip power semiconductor devices are adopted, the length of the wires used to manufacture modules of the same size increases, exacerbating the problem of reduced allowable current due to increased wire length. This, in turn, increases the need to eliminate wires that serve as current paths.

[0044] A printed circuit board (13) may include a conductive pattern (P) using a metal material such as copper (Cu), gold (Au), or silver (Ag) with high thermal and electrical conductivity on the surface of an insulating layer (131) made of a glass fiber epoxy laminate material such as FR (Flame Retardant) 4. In addition, the printed circuit board (13) may include a conductive via hole (H) penetrating the upper and lower surfaces. A conductive pattern (P) may be formed to extend on an inner surface of the conductive via hole (H), and an electrical connection may be formed between the conductive pattern (P) formed on the upper surface of the printed circuit board (13) and an element arranged on the lower surface of the printed circuit board (13) by filling the interior of the conductive via hole (H) with a conductive material.

[0045] In the embodiment illustrated in FIG. 1, the lower surface of the printed circuit board (13) may be arranged in a form that directly faces the upper surface of the insulating substrate (11), that is, a portion of the upper surface of the upper metal layer (111) and the upper surface of the power semiconductor element (12). In this case, since the power semiconductor element (12) has a structure that protrudes upward from the upper surface of the insulating substrate (11), a concave portion (C1) may be formed in a portion corresponding to the position where the power semiconductor element (12) is arranged by processing the lower surface of the printed circuit board (13) so as to provide a space in which the power semiconductor element (12) is accommodated.

[0046] The conductive via hole (H) of the printed circuit board (13) can be formed on the upper part corresponding to the upper metal layer (111) of the insulating substrate (11) and the terminal portion (not shown) on the upper surface of the power semiconductor element (12).

[0047] Electrical connection between the conductive via hole (H) of the printed circuit board (13), the metal layer (111) of the insulating substrate (11), and the terminal portion of the power semiconductor element (12) can be made using various electrical connection techniques known in the art.

[0048] For example, after solder is provided on the metal layer (111) of the insulating substrate (11) to form an electrical connection and the terminal portion of the power semiconductor element (12), a printed circuit board (13) is placed thereon and an electrical connection can be formed through a solder reflow process.

[0049] As another example, an electrical connection can be formed through a process of placing a printed circuit board (13) on top of a metal layer (111) of an insulating substrate (11) and a power semiconductor element (12), and then filling and solidifying a conductive metal material in the space inside a conductive via hole (H).

[0050] In an embodiment of the present invention, an electrical connection between a metal layer (111) of an insulating substrate (11) and a power semiconductor element (12) and / or an electrical connection between power semiconductor elements (12) is achieved through a conductive via hole (H) and a conductive pattern (P). That is, as in a conventional power module, all wires made of Al that form a path for current to flow are removed, and an electrical connection for current flow can be achieved through a conductive via hole (H) and a conductive pattern (P) made of a metal material having excellent electrical conductivity, such as Cu, Au, or Ag.

[0051] Accordingly, embodiments of the present invention can improve product reliability by allowing the same rated current to flow with a smaller thickness and area compared to conventional Al wires. In particular, embodiments of the present invention can implement a low-inductance module by reducing parasitic inductance.

[0052] In addition, the embodiment of the present invention can implement a wide bonding area and a short bonding loop compared to a conventional Al material wire, thereby reducing stray inductance.

[0053] In addition, the embodiment of the present invention can form an electrical connection even in a location where an electrical connection is impossible due to structural limitations in conventional wire wiring by applying a printed circuit board with a high degree of freedom in pattern implementation, thereby improving the degree of freedom in circuit design.

[0054] In addition, the embodiment of the present invention can omit the wire bonding process that requires detailed precision, thereby simplifying the production process and thereby achieving an increase in production speed and a reduction in the production cost of the product.

[0055] Embodiments of the present invention may further include passive electrical and electronic components, such as resistors and capacitors, or active electrical and electronic components, such as diodes and transistors, mounted on a printed circuit board (13). Embodiments of the present invention are more advantageous for integration because they can place and operate various electrical and electronic components (14) required for power supply, control, or monitoring of power semiconductor components and for the operation of a power module on a printed circuit board (13).

[0056] An embodiment of the present invention may further include a mold portion (15) formed to seal the elements constituting the power module (10) with an insulating material to protect each element constituting the power module (10) and the physical connection state between them from dust, moisture, impact, etc.

[0057] For example, the mold part (15) can be manufactured through a molding process using EMC (Epoxy Mold Compound), a thermosetting resin, as a material, or can be formed by covering several elements on the upper part of the insulating substrate (11) with a separate case and then filling the inside with silicone gel or soft epoxy resin.

[0058] Meanwhile, an embodiment of the present invention may further include a lead (15) having one end bonded to the upper surface of a printed circuit board (13) and the other end exposed to the outside of a mold portion (15) to exchange current with the outside. Although not shown in FIG. 1, the lead (15) may be implemented in a form including a terminal holder having a hollow portion and one end electrically bonded to the printed circuit board (13), and a terminal bar having one end inserted into the hollow portion of the terminal holder by a cold welding method and bonded, and the other end extending to the outside of the mold portion (15).

[0059] This lead structure can omit the lead frame of conventional power modules, thereby simplifying the manufacturing process and reducing manufacturing costs, as well as improving the freedom of power module design that was previously limited in forming electrical connections with the lead frame.

[0060] FIG. 3 is a cross-sectional view of a power module having an internal connection structure using a printed circuit board according to another embodiment of the present invention.

[0061] The embodiment illustrated in FIG. 3 further includes a dielectric layer (21) disposed between the insulating substrate (11) and the printed circuit board (13). That is, the embodiment illustrated in FIG. 3 is an embodiment in which, instead of forming a recess (C1) for accommodating a power semiconductor element (12) on the lower surface of the printed circuit board (13), a dielectric layer (21) having a thickness corresponding to or greater than the height of the power semiconductor element (12) is disposed.

[0062] The dielectric layer (21) can be implemented with various dielectric materials that do not have conductivity. The dielectric layer (21) can have a hollow portion (C2) penetrating the upper and lower surfaces to accommodate a power semiconductor element (12).

[0063] The thickness of the dielectric layer (21) can be appropriately adjusted according to the size of the required power module, thereby enabling the production of power modules in response to various size requirements.

[0064] As described above, a power module having an internal connection structure using a printed circuit board according to various embodiments of the present invention can achieve an improvement in rated current and a reduction in parasitic inductance and stray inductance by replacing the Al material wire used as an electrical connection means for current flow in a conventional power module with a conductive pattern and conductive via hole of the printed circuit board.

[0065] In addition, a power module having an internal connection structure using a printed circuit board according to various embodiments of the present invention can improve the degree of freedom in circuit design by forming electrical connections using conductive patterns and conductive via holes of the printed circuit board, and can reduce production time and production cost through process simplification.

[0066] In addition, a power module having an internal connection structure using a printed circuit board according to various embodiments of the present invention is advantageous in terms of integration because additional electrical and electronic components can be placed on the printed circuit board, and leads for current input / output with the outside can be bonded to the printed circuit board, so cost reduction due to omission of a lead frame, process simplification, and increased design freedom can be expected.

Claims

1. An insulating substrate including a metal layer; A power semiconductor element disposed on the upper surface of the metal layer of the insulating substrate; and A printed circuit board is disposed on top of the power semiconductor device and includes a conductive pattern and a conductive via hole electrically connected to the terminal of the power semiconductor device and the metal layer on the upper surface of the insulating substrate. A power module having an internal connection structure using a printed circuit board, characterized in that when a current flow occurs, current is conducted between the power semiconductor element and the metal layer through the conductive pattern and the conductive via hole.

2. In claim 1, A power module having an internal connection structure using a printed circuit board, characterized in that a concave portion for accommodating the power semiconductor element is formed on the lower surface of the insulating substrate.

3. In claim 1, A power module having an internal connection structure using a printed circuit board, characterized in that the printed circuit board further includes a dielectric layer disposed between the metal layer and the printed circuit board, and the dielectric layer includes a hollow portion for accommodating the power semiconductor element.

4. In claim 1, A power module having an internal connection structure using a printed circuit board, characterized in that it further includes an active electrical / electronic element or a passive electrical / electronic element arranged on the printed circuit board.

5. In claim 1, A power module having an internal connection structure using a printed circuit board, characterized in that it further includes a mold part that seals the power semiconductor element and the printed circuit board so that the other surface of the insulating substrate on which the power semiconductor element is not arranged is exposed.

6. In claim 5, A power module having an internal connection structure using a printed circuit board, characterized in that it further includes a lead having one end bonded to the upper surface of the printed circuit board and the other end exposed to the outside of the mold part to exchange current with the outside.

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