Power module includig printed circuit board

Abstract

A power module is disclosed having a printed circuit board comprising: a metal substrate; a power semiconductor device disposed on one surface of the metal substrate; a printed circuit board having a conductive pattern on at least one surface; a conductive wire having both ends connected to the power semiconductor device and the conductive pattern; and a power lead having one end connected to the conductive pattern.

Description

Technology Field

[0001] The present invention relates to a power module, and more specifically, to a power module capable of reducing the length of wires for electrical connections by applying a Printed Circuit Board (PCB). Background Technology

[0003] A power module is a device used to convert direct current power into alternating current power when driving motors or compressors in home appliances, hybrid vehicles, electric vehicles, etc.

[0004] Typically, a power module may include a substrate, a power semiconductor device which is a switching element bonded to the substrate, a power lead that applies power to the power semiconductor device, and a signal lead that provides a control signal to the power semiconductor device.

[0005] Power semiconductor devices within power modules, which are switching elements, generate a significant amount of heat due to the repeated on / off operation. To facilitate the dissipation of this heat, power semiconductor devices are fabricated by bonding them onto a substrate such as DBC (Direct Bonded Copper). Additionally, power leads are electrically connected to power semiconductor devices via wires (primarily made of aluminum (Al)) to allow for the application of current from the outside and the output of current to the outside.

[0006] A problem arises with these aluminum wires in that the current capacity that can flow through them decreases as their length increases.

[0007] In addition, depending on the fin structure exposed to the outside of the power module, it is manufactured in a shape that has bent sections rather than straight lines. However, when subjected to severe stress, such a structure with bent sections may cause cracks or wires to separate.

[0008] Therefore, in the field of power modules, new technology is required to shorten the length of current-carrying wires and minimize bending points where bending occurs.

[0010] The matters described as background technology above are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. Prior art literature

[0012] (Patent Document 0001) KR 10-2017-0092750 A(Patent Document 0002) KR 10-2017-0069363 A(Patent Document 0003) KR 10-2018-0052143 A The problem to be solved

[0013] Accordingly, the present invention aims to solve the technical problem of providing a power module that applies a printed circuit board capable of reducing the length of the wire through which current flows and minimizing the bending portion of the wire.

[0015] The problems to be solved by the present invention are not limited to those described above, and other problems and advantages of the present invention not mentioned can be understood from the following description and will become more clearly known through the embodiments of the present invention. Furthermore, a person skilled in the art to which the present invention pertains will readily understand that the problems and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0017] As a means to solve the above technical problem, the present invention is,

[0018] Metal substrate;

[0019] A power semiconductor device disposed on one surface of the metal substrate;

[0020] A printed circuit board having a conductive pattern on at least one surface;

[0021] A conductive wire with both ends connected to the power semiconductor device and the conductive pattern; and

[0022] A power lead connected at one end to the above conductive pattern;

[0023] A power module is provided that incorporates a printed circuit board including

[0024] An embodiment of the present invention may further include a mold portion that molds a portion of the power semiconductor device, the printed circuit board, the conductive wire, and the power lead so that the other side of the metal substrate on which the power semiconductor device is not placed is exposed.

[0025] In an embodiment of the present invention, the other side 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.

[0026] In an embodiment of the present invention, the metal substrate comprises a first metal layer, an insulating layer having its lower surface bonded to the upper surface of the first metal layer, and a second metal layer having its lower surface bonded to the upper surface of the insulating layer, and the power semiconductor device may be disposed on the upper surface of the second metal layer.

[0027] 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.

[0028] An embodiment of the present invention may further include active and passive components disposed on the printed circuit board. Effects of the invention

[0030] According to the power module applying the above-described printed circuit board, by interposing the printed circuit board between the lead for exchanging current with the outside and the power semiconductor device and allowing current to flow through the conductive pattern of the printed circuit board, the length of the wire through which current flows can be significantly reduced and the bending of the wire can be minimized compared to a structure in which the lead and the power semiconductor device are directly connected through a wire.

[0031] Accordingly, according to the power module using the above-mentioned printed circuit board, the capacity of the power-convertible current can be increased and the stress applied to the wire can be minimized, thereby preventing wire cracking or lifting.

[0032] In addition, according to the power module applying the above-mentioned printed circuit board, the spatial constraints of the wire structure can be eliminated, thereby increasing the freedom of circuit design, and additional electrical components can be added to the printed circuit board, enabling various performance improvements of the power module.

[0034] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0036] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to facilitate a better understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in the following drawings. FIG. 1 is a cross-sectional view of a power module having a printed circuit board according to one embodiment of the present invention. FIGS. 2 and FIGS. 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. Specific details for implementing the invention

[0037] 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.

[0038] Specific structural or functional descriptions of the embodiments described below are disclosed merely for illustrative purposes and may be modified and implemented in various forms. Accordingly, the embodiments are not limited to specific disclosed forms, and the scope of this specification includes modifications, equivalents, or substitutions that fall within the technical concept.

[0039] Terms such as "first" or "second" may be used to describe various components, but these terms should be interpreted solely for the purpose of distinguishing one component from another. For example, the first component may be named the second component, and similarly, the second component may be named the first component.

[0040] When it is stated that a component is "connected" to another component, it should be understood that it may be directly connected to or joined to that other component, or that there may be other components in between.

[0041] The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to specify the existence of the described features, numbers, steps, actions, components, parts, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0042] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0044] FIG. 1 is a cross-sectional view of a power module having a printed circuit board according to one embodiment of the present invention.

[0045] Referring to FIG. 1, a power module (10) having a printed circuit board according to one embodiment of the present invention may be configured to include a metal substrate (11), a power semiconductor device (121, 122) disposed 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) with both ends connected to the power semiconductor device (121) and the conductive pattern (131), and a power lead (14) with one end connected to the conductive pattern (131).

[0046] In addition, a power module (10) having a printed circuit board according to one embodiment of the present invention may further include a mold part (15) made of an insulating material that molds the elements constituting the power module (10). Furthermore, a power module (10) having a printed circuit board according to one embodiment of the present invention may further include passive components and active components (not shown) disposed on one surface of a printed circuit board (13).

[0047] 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 field of technology, such a substrate is referred to as a Direct Bonded Copper (DBC) substrate. By ensuring sufficient thickness of the metal layers (111, 113), such a metal substrate can effectively dissipate heat generated from power semiconductor devices (121, 122) bonded to the metal substrate (11). That is, the metal substrate (11) is a substrate used for efficient cooling of power semiconductor devices (121, 122) that generate a lot of heat.

[0048] Power semiconductor devices (121, 122) may include an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) and / or a diode as switching semiconductor devices for power conversion known in the art.

[0049] The embodiment illustrated in FIG. 1 relates to a power module comprising two power semiconductor devices (typically an IGBT and a diode), but depending on the type or material of the device, a power semiconductor device implemented as a single chip may also be applied. For example, SiC (silicon carbide)-based power semiconductor devices, which have recently gained popularity, can be manufactured in the form of a single chip. When a power semiconductor device in the form of a single chip is adopted, the length of the wire used to manufacture a module of the same size becomes longer, so the need to reduce the wire length becomes even greater.

[0050] Power semiconductor devices (121, 122) can be fixedly placed on a metal substrate by soldering or sintering, which are component joining processes known in the art.

[0051] 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) which has high thermal and electrical conductivity. The conductive pattern (131) formed on the printed circuit board (13) may be provided to a power semiconductor device (121) or may form a path through which current output from the power semiconductor device (121) can flow.

[0052] Since the conductive pattern (131) formed on the printed circuit board (13) can be formed relatively easily as desired, 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 location where the power lead through which current flows is connected can be determined in various ways, thereby improving the design freedom of the power module.

[0053] In addition, various electrical and electronic components, including passive components such as resistors and capacitors, or active components such as diodes and transistors, may be mounted and used on the printed circuit board (13) as needed.

[0054] The power lead (14) is an element that receives current supplied to the power semiconductor device (121, 122) from outside the power module (10) or outputs current output from the power semiconductor device (121, 122) to outside the power module (10).

[0055] Conventionally, the power lead (14) was connected directly to the power semiconductor device (121) via a wire. Therefore, for a power module of the same size, a relatively long wire was required to connect the power semiconductor device (121) and the power lead, and this resulted in a problem of reduced current capacity due to the increased wire length.

[0056] In contrast, an embodiment of the present invention can solve the problem of reduced current capacity by reducing the length of the conductive wire (W1) by interposing a printed circuit board (13) having a conductive pattern (131).

[0057] The mold part (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, shock, etc. For example, the mold part (15) may be made of Epoxy Mold Compound (EMC), which is a thermosetting resin.

[0058] Meanwhile, in order to easily discharge heat generated by power semiconductor devices (121, 122) to the outside of the power module, a mold portion (15) may be formed so that the lower surface of the metal substrate (11) on which power semiconductor devices (121, 122) are not placed is exposed to the outside.

[0059] In addition, the printed circuit board (13), through which heat transfer is achieved via the connection of the wire (W1), may also have a molded portion (15) formed so that the lower surface, on which the conductive pattern (131) is not formed, is exposed to the outside so that a heat dissipation effect can be obtained.

[0060] For the lower surface exposure 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 side by side at the same level. In an embodiment of the present invention, by installing the printed circuit board (13) side by side with the metal substrate (11), the size of the expensive metal substrate (11) can be reduced, which can also help reduce manufacturing costs.

[0061] In FIG. 1, reference numeral 'W2' is a conductive wire arranged for the flow of current between two types of power semiconductor devices (121, 122), reference numeral 'W3' is a wire through which a control signal for controlling the power semiconductor device (122) is transmitted, and reference numeral '16' is a signal lead for receiving a control signal provided from outside the power module (10).

[0062] FIGS. 2 and FIGS. 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.

[0063] In the conventional power module illustrated in FIG. 2, the power semiconductor device (121) and the power lead (lead frame) are directly connected through a wire (W1), so a bend occurs in the wire (W1) depending on the arrangement of the lead frame.

[0064] 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 required, and above all, the length of the wire (W1) can be significantly reduced by placing the printed circuit board (13) adjacent to the power semiconductor device (121).

[0065] As described above, a power module incorporating a printed circuit board according to an embodiment of the present invention can significantly reduce the length of the wire through which current flows and minimize bending of the wire compared to a structure in which the lead and the power semiconductor device are directly connected via a wire by interposing the printed circuit board between the lead for exchanging current with the outside and the power semiconductor device and allowing current to flow through the conductive pattern of the printed circuit board.

[0066] Due to these structural features, a power module incorporating a printed circuit board according to an embodiment of the present invention can increase the capacity of power-convertible current and minimize stress applied to the wires, thereby preventing wire cracking or lifting. In addition, a power module incorporating a printed circuit board according to an embodiment of the present invention can increase the freedom of circuit design by resolving 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. Explanation of the symbols

[0068] 10: Power module 11: Metal substrate 111, 113: Metal layer 112: Insulating layer 121, 122: Power semiconductor devices 13: Printed circuit board 131: Challenging Pattern 14: Power Lead 15: Mold part 16: Signal lead W1, W2: Power wires W3: Signal wire

Claims

Claim 1 A power module having a printed circuit board, comprising: a metal substrate; a power semiconductor device disposed on one side of the metal substrate; a printed circuit board having a conductive pattern on at least one side; a conductive wire with both ends connected to the power semiconductor device and the conductive pattern; a power lead with one end connected to the conductive pattern; and a mold portion that molds a portion of the power semiconductor device, the printed circuit board, the conductive wire, and the power lead such that the other side of the metal substrate on which the power semiconductor device is not disposed is exposed, wherein the printed circuit board is disposed around the metal substrate and is spaced apart from the metal substrate, and current flow between the power lead and the power semiconductor device is made through the conductive pattern of the printed circuit board to which the power lead and the conductive wire are connected, and the other side of the printed circuit board on which the conductive wire and the power lead are not connected is exposed to the outside of the mold portion, and the printed circuit board is disposed side by side with the metal substrate at the same level. Claim 2 delete Claim 3 delete Claim 4 A power module applying a printed circuit board according to claim 1, wherein the metal substrate comprises 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, wherein the power semiconductor element is disposed on the upper surface of the second metal layer. Claim 5 delete Claim 6 A power module having a printed circuit board according to claim 1, further comprising active and passive components disposed on the printed circuit board.

Images