Power module employing printed circuit board

Abstract

Disclosed is a power module employing a printed circuit board, the power module comprising: a metal substrate; a power semiconductor device which is disposed on one surface of the metal substrate; a printed circuit board which has a conductive pattern on at least one surface thereof; a conductive wire both ends of which are connected to the power semiconductor device and the conductive pattern; and a power lead one end of which is connected to the conductive pattern.

Description

Power module using printed circuit board

[0001] The present invention relates to a power module, and more particularly, to a power module capable of reducing the length of wires for electrical connection by applying 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] The problem with these aluminum wires is that as their length increases, the current capacity that can flow through them decreases.

[0006] In addition, the pin structure exposed to the outside of the power module 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 power module field, new technologies are required that can shorten the length of current-carrying wires and minimize bending points.

[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 using a printed circuit board capable of reducing the length of a wire through which current flows and minimizing the bending portion of the wire.

[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] metal substrate;

[0013] A power semiconductor element disposed on one surface of the above metal substrate;

[0014] A printed circuit board having a conductive pattern on at least one side;

[0015] A conductive wire having both ends connected to the power semiconductor element and the conductive pattern; and

[0016] A power lead connected at one end to the above-mentioned challenging pattern;

[0017] A power module using a printed circuit board including a

[0018] An embodiment of the present invention may further include a molding part that molds the power semiconductor element, the printed circuit board, the conductive wire, and a portion of the power lead so that the other surface of the metal substrate on which the power semiconductor element is not arranged is exposed.

[0019] In an embodiment of the present invention, the other surface of the printed circuit board to which the conductive wire and the power lead are not connected may be exposed to the outside of the mold portion.

[0020] In an embodiment of the present invention, the metal substrate includes a first metal layer, an insulating layer having a lower surface bonded to an upper surface of the first metal layer, and a second metal layer having a lower surface bonded to an upper surface of the insulating layer, and the power semiconductor element may be disposed on an upper surface of the second metal layer.

[0021] In an embodiment of the present invention, the printed circuit board may be arranged side by side with the metal substrate at the same level.

[0022] Embodiments of the present invention may further include active components and passive components arranged on the printed circuit board.

[0023] According to the power module using the above printed circuit board, the printed circuit board is interposed between the lead for exchanging current with the outside and the power semiconductor element, and the current flows through the conductive pattern of the printed circuit board, thereby significantly reducing the length of the wire through which the current flows and minimizing bending of the wire compared to a structure in which the lead and the power semiconductor element are directly connected through a wire.

[0024] Accordingly, according to the power module using the printed circuit board, the capacity of the current that can be converted into power can be increased and the stress applied to the wire can be minimized to prevent wire cracking or lifting.

[0025] In addition, according to the power module using the printed circuit board, the degree of freedom in circuit design can be increased by eliminating the spatial constraints of the wire structure, and additional electrical components can be added to the printed circuit board, thereby enabling various performance improvements of the power module.

[0026] 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.

[0027] 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.

[0028] FIG. 1 is a cross-sectional view of a power module using a printed circuit board according to one embodiment of the present invention.

[0029] FIG. 2 and FIG. 3 are drawings for comparing and explaining the wire shape of a conventional power module and a power module according to an embodiment of the present invention.

[0030] Hereinafter, a permanent magnet type magnetic field generating device according to various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

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

[0037] Referring to FIG. 1, a power module (10) using a printed circuit board according to one embodiment of the present invention may be configured to include a metal substrate (11), a power semiconductor element (121, 122) arranged on one surface of the metal substrate (11), a printed circuit board (13) having a conductive pattern (131) on at least one surface, a conductive wire (W1) having both ends connected to the power semiconductor element (121) and the conductive pattern (131), and a power lead (14) having one end connected to the conductive pattern (131).

[0038] In addition, the power module (10) using the printed circuit board according to one embodiment of the present invention may further include a mold part (15) made of an insulating material for molding elements constituting the power module (10). In addition, the power module (10) using the printed circuit board according to one embodiment of the present invention may further include passive elements and active elements (not shown) arranged on one surface of the printed circuit board (13).

[0039] The metal 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. In the art, such a substrate is called a Direct Bonded Copper (DBC) substrate. Such a metal substrate can effectively disperse heat generated from power semiconductor elements (121, 122) bonded on the metal substrate (11) by ensuring a sufficient thickness of the metal layers (111, 113). In other words, the metal substrate (11) is a substrate used for efficient cooling of power semiconductor elements (121, 122) that generate a lot of heat.

[0040] The power semiconductor device (121, 122) 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.

[0041] The embodiment illustrated in FIG. 1 relates to a power module including two power semiconductor devices (typically, an IGBT and a diode), but a power semiconductor device implemented as a single chip may also be applied depending on the type or material of the device. For example, the recently popular SiC (silicon carbide)-based power semiconductor device can be manufactured in the form of a single chip. If a single-chip power semiconductor device is employed, the length of the wire used to manufacture a module of the same size becomes longer, and thus the need for reducing the wire length becomes even greater.

[0042] Power semiconductor elements (121, 122) can be fixedly arranged on a metal substrate by soldering or sintering, which are component bonding processes known in the art.

[0043] A printed circuit board (13) may include a conductive pattern (131) on its surface using a metal material such as copper (Cu), gold (Au), or silver (Ag) with high thermal and electrical conductivity. The conductive pattern (131) formed on the printed circuit board (13) may form a path through which current supplied to or output from a power semiconductor device (121) may flow.

[0044] The conductive pattern (131) formed on the printed circuit board (13) can be formed relatively easily into a desired shape, so that the path through which current flows can be adjusted by appropriately forming the shape of the conductive pattern (131). That is, by appropriately forming the conductive pattern (131) as needed, the position at which the power lead through which current flows is connected can be determined in various ways, thereby improving the design freedom of the power module.

[0045] In addition, various electrical and electronic components including passive components such as resistors and capacitors or active components such as diodes and transistors can be mounted and used on the printed circuit board (13) as needed.

[0046] The power lead (14) is an element that receives current supplied to the power semiconductor element (121, 122) from the outside of the power module (10) or outputs current output from the power semiconductor element (121, 122) to the outside of the power module (10).

[0047] In the past, the power lead (14) was directly connected to the power semiconductor element (121) via a wire. Therefore, in the case of a power module of the same size, a relatively long wire was required to connect the power semiconductor element (121) and the power lead, which resulted in a problem of a decrease in current capacity due to an increase in the wire length.

[0048] In contrast, the embodiment of the present invention can solve the problem of current capacity reduction by reducing the length of the conductive wire (W1) by interposing a printed circuit board (13) having a conductive pattern (131).

[0049] The mold portion (15) may be 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 between them from dust, moisture, impact, etc. For example, the mold portion (15) may be made of EMC (Epoxy Mold Compound), which is a thermosetting resin.

[0050] Meanwhile, in order to easily discharge heat generated by the power semiconductor elements (121, 122) to the outside of the power module, a mold part (15) may be formed so that the lower surface of the metal substrate (11) on which the power semiconductor elements (121, 122) are not placed is exposed to the outside.

[0051] In addition, the printed circuit board (13) on which heat transfer occurs through the connection of the wire (W1) can also have a mold portion (15) formed so that the lower surface where the conductive pattern (131) is not formed is exposed to the outside so that a heat dissipation effect can be obtained.

[0052] In order to expose the lower surface by the mold part (15), the lower surface of the metal substrate (11) and the lower surface of the printed circuit board (13) can be formed parallel to each other at the same level. In the embodiment of the present invention, by installing the printed circuit board (13) parallel to the metal substrate (11), the size of the expensive metal substrate (11) can be reduced, which can also help reduce the manufacturing cost.

[0053] In Fig. 1, reference symbol 'W2' is a conductive wire arranged for the flow of current between two types of power semiconductor elements (121, 122), reference symbol 'W3' is a wire through which a control signal for controlling the power semiconductor element (122) is transmitted, and reference symbol '16' is a signal lead for receiving a control signal provided from outside the power module (10).

[0054] FIG. 2 and FIG. 3 are drawings for comparing and explaining the wire shape of a conventional power module and a power module according to an embodiment of the present invention.

[0055] The conventional power module illustrated in Fig. 2 has a structure in which a power semiconductor element (121) and a power lead (lead frame) are directly connected via a wire (W1), so a bend occurs in the wire (W1) depending on the arrangement of the lead frame.

[0056] In contrast, in the case of the module illustrated in FIG. 3 and the power module according to one embodiment of the present invention, the shape of the path through which current flows can be freely formed by the conductive pattern (131) on the printed circuit board (13), so bending of the wire (W1) is not necessary, and above all, the length of the wire (W1) can be significantly reduced by arranging the printed circuit board (13) adjacent to the power semiconductor element (121).

[0057] As described above, a power module using a printed circuit board according to an embodiment of the present invention interposes a printed circuit board between a lead for exchanging current with the outside and a power semiconductor element, and allows current to flow through a conductive pattern of the printed circuit board, thereby significantly reducing the length of the wire through which current flows and minimizing bending of the wire compared to a structure in which a lead and a power semiconductor element are directly connected through a wire.

[0058] Due to these structural features, a power module using a printed circuit board according to an embodiment of the present invention can increase the capacity of a power-convertible current and minimize the stress applied to the wires, thereby preventing wire cracks or lifting. In addition, a power module using a printed circuit board according to an embodiment of the present invention can increase the degree of freedom in circuit design by eliminating the spatial constraints of the wire structure, and can add additional electrical components on the printed circuit board, thereby enabling various performance improvements of the power module.

Claims

1. Metal substrate; A power semiconductor element disposed on one surface of the above metal substrate; A printed circuit board having a conductive pattern on at least one side; A conductive wire having both ends connected to the power semiconductor element and the conductive pattern; and A power lead connected at one end to the above-mentioned challenging pattern; A power module using a printed circuit board including:

2. In claim 1, A power module using a printed circuit board, characterized in that it further includes a molding part that molds the power semiconductor element, the printed circuit board, the conductive wire, and a portion of the power lead so that the other surface of the metal substrate on which the power semiconductor element is not arranged is exposed.

3. In claim 2, A power module using a printed circuit board, characterized in that the other surface of the printed circuit board to which the conductive wire and the power lead are not connected is exposed to the outside of the mold part.

4. In claim 1, the metal substrate, A power module using a printed circuit board, characterized in that it includes a first metal layer, an insulating layer having a lower surface bonded to the upper surface of the first metal layer, and a second metal layer having a lower surface bonded to the upper surface of the insulating layer, and the power semiconductor element is arranged on the upper surface of the second metal layer.

5. In claim 1, A power module using a printed circuit board, characterized in that the printed circuit board and the metal substrate are arranged side by side at the same level.

6. In claim 1, A power module using a printed circuit board, characterized in that it further includes active components and passive components arranged on the printed circuit board.

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