Power semiconductor module with metal PCB

Abstract

A power semiconductor module equipped with a metal PCB is disclosed. The power semiconductor module equipped with a metal PCB according to the present invention comprises: a semiconductor case on which a power semiconductor is disposed; a PCB electrically connected to the power semiconductor and having an opening formed therein; a metal PCB joined to the semiconductor case by solder through the opening; and a heat sink assembled on one surface of the metal PCB. The present invention can provide a power semiconductor module equipped with a metal PCB that can shorten the manufacturing time of the power semiconductor module.

Description

Technology Field

[0001] The present invention relates to a power semiconductor module equipped with a metal PCB, and more specifically, to a power semiconductor module equipped with a metal PCB that can shorten the manufacturing time of the power semiconductor module and increase the heat dissipation effect. Background Technology

[0003] Generally, power semiconductor modules switch large amounts of power in motor control applications such as inverters and soft motor starters, resulting in significant heat loss during operation. Since failure to effectively dissipate this heat poses a risk of malfunction, power semiconductors must be cooled.

[0004] As power semiconductor modules become slimmer and more compact, temperature issues are becoming a critical factor in product reliability. The heat dissipation structure of conventional power semiconductor modules is as follows.

[0005] Referring to FIG. 1, the heat dissipation structure of a conventional power semiconductor module consists of a semiconductor case (1) in which a power semiconductor (2) is bonded inside, a heat sink (4) bonded to one side of the semiconductor case (1), and a heat dissipation grease (3) applied between the heat sink (4) and the semiconductor case (1).

[0006] The heat sink (4) is made of a metal material with excellent thermal conductivity and is connected to the semiconductor case (1) through a screw (5). The heat dissipation grease (3) is intended to improve contact between the heat sink (4) and the semiconductor case (1), thereby preventing the formation of a gap between them and facilitating heat transfer.

[0007] Therefore, heat generated in the power semiconductor (2) is transferred to the heat sink (4) via the semiconductor case (1) and the heat dissipation grease (3) and radiated into the surrounding air. However, in the heat transfer system of the power semiconductor module, there is a limit to lowering the temperature at the junction (2a) of the power semiconductor (2) due to the temperature rise caused by the thermal resistance of the heat dissipation grease (3). This not only reduces the reliability of the product but also acts as a major obstacle to making the power semiconductor module slimmer and more compact.

[0008] In order to solve the problems of the aforementioned conventional technology, a power semiconductor module (10) structure is presented in which a semiconductor case (13) in which a power semiconductor (14) is installed and a heat sink (12) are integrated as shown in FIG. 2, so that heat transfer from the power semiconductor (14) to the heat sink (12) is made smoother.

[0009] Referring to FIG. 2, the power semiconductor module (10) is composed of a power semiconductor (14) electrically connected to a circuit board (11) via a lead wire (14b), a semiconductor case (13) in which the power semiconductor (14) is bonded internally, and a heat sink (12) for dissipating heat generated from the power semiconductor (14) into the air. The heat sink (12) and the semiconductor case (13) are bonded together via solder (15) with the circuit board (11) in between. In addition, an opening (11a) is formed in the circuit board (11) to bond the semiconductor case (13) and the heat sink (12) with solder (15). At this time, the width of the opening (11a) is configured to be smaller than the width of the heat sink (12), and accordingly, the circuit board (11) is placed so as to overlap between the heat sink (12) and the semiconductor case (13). That is, cream solder (15) is applied to the upper surface of the heat sink (12), and a circuit board (11) with a semiconductor case (13) assembled thereon is mounted so that the opening (11a) aligns with it, and the semiconductor case (13) and the heat sink (12) are joined through a soldering method called reflow soldering.

[0010] The manufacturing method of the power semiconductor module (10) illustrated in FIG. 2 comprises a printing step of applying solder (15) to a heat sink (12), a mounting step of mounting a semiconductor case (13) on which a power semiconductor (14) is bonded onto the solder (15), a preheating step of preheating the heat sink (12) and the semiconductor case (13), a heating step of heating them above the melting point of the solder (15), and a cooling step (S5) of cooling them.

[0011] However, because the heat sink is very thick compared to other components, the preheating stage takes too long, increasing process time and costs. Additionally, there are problems where power semiconductors are damaged or degraded due to prolonged exposure to heat, and consequently, the aforementioned process can only be applied to high-priced power semiconductors that have undergone special treatment. Prior art literature

[0013] KR 10-0415821 The problem to be solved

[0014] Accordingly, the present invention is devised to solve the aforementioned problems and aims to provide a power semiconductor module equipped with a metal PCB that can shorten the manufacturing time of the power semiconductor module.

[0015] In addition, the present invention provides a power semiconductor module equipped with a metal PCB capable of increasing the heat dissipation effect of the power semiconductor module.

[0016] Other objects of the present invention will become more apparent through the preferred embodiments described below. means of solving the problem

[0018] According to one aspect of the present invention, a power semiconductor module equipped with a metal PCB comprises: a semiconductor case on which a power semiconductor is disposed; a PCB electrically connected to the power semiconductor and having an opening formed therein; a metal PCB joined to the semiconductor case by solder through the opening; and a heat sink assembled on one surface of the metal PCB.

[0019] Here, the PCB is placed between the semiconductor case and the metal PCB, and the heat sink can be assembled on the side of the metal PCB where the PCB is not placed.

[0020] Here, the heatsink can be assembled to contact the metal PCB through screws.

[0021] Here, in order to increase the contact area between the heatsink and the metal PCB, engraved and embossed patterns may be formed on the contact surface between the heatsink and the metal PCB.

[0022] Here, the pattern may be any one of a tot pattern, a linear pattern, and a grid pattern.

[0023] According to another aspect of the present invention, a method for manufacturing a power semiconductor module equipped with a metal PCB comprises: a printing step of placing the metal PCB on a jig device and applying solder; a step of placing a PCB with a semiconductor case assembled thereon on the metal PCB—wherein the PCB has an opening formed therein and the power semiconductor case comes into contact with the solder as the solder is exposed through the opening—; a preheating step of preheating the metal PCB and the semiconductor case; a heating step of heating above the melting point of the solder to melt the solder; a cooling step of cooling the molten solder to bond the metal PCB and the semiconductor case; and an assembly step of discharging the integrated PCB, the power semiconductor case, and the metal PCB from the jig device and then joining a heat sink.

[0024] Here, the heatsink can be assembled to contact the metal PCB through screws.

[0025] Here, in order to increase the contact area between the heatsink and the metal PCB, engraved and embossed patterns may be formed on the contact surface between the heatsink and the metal PCB. Effects of the invention

[0027] The present invention can provide a power semiconductor module equipped with a metal PCB that can shorten the manufacturing time of the power semiconductor module.

[0028] In addition, the present invention can provide a power semiconductor module equipped with a metal PCB that can increase the heat dissipation effect of the power semiconductor module. Brief explanation of the drawing

[0030] FIG. 1 is a cross-sectional view showing the configuration of a power semiconductor module having a heat sink according to the prior art. FIG. 2 is a cross-sectional view showing the configuration of a power semiconductor module equipped with a PCB having an open portion according to the prior art. FIG. 3 is a cross-sectional view showing the configuration of a power semiconductor module according to one embodiment of the present invention. FIG. 4 is a cross-sectional view showing the configuration of a power semiconductor module according to another embodiment of the present invention. FIG. 5 is a flowchart showing the manufacturing process of a power semiconductor module according to one embodiment of the present invention. FIG. 6 is a cross-sectional view showing the printing step of a power semiconductor module according to one embodiment of the present invention. FIG. 7 is a cross-sectional view showing the mounting step of a power semiconductor module according to one embodiment of the present invention. FIG. 8 is a cross-sectional view showing the assembly steps of a power semiconductor module according to one embodiment of the present invention. Specific details for implementing the invention

[0031] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention.

[0032] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0033] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, 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. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0035] FIG. 3 is a cross-sectional view showing the configuration of a power semiconductor module according to one embodiment of the present invention, and FIG. 4 is a cross-sectional view showing the configuration of a power semiconductor module according to another embodiment of the present invention.

[0036] Referring to FIG. 3, a power semiconductor module (100) equipped with a metal PCB according to the present invention comprises a semiconductor case (113) on which a power semiconductor (114) is disposed, a PCB (111) electrically connected to the power semiconductor (114) and having an opening (111a) formed therein, a metal PCB (116) joined to the semiconductor case (113) by solder (115) through the opening (111a); and a heat sink (112) assembled on one side of the metal PCB (116). Here, the PCB (111) is disposed between the semiconductor case (113) and the metal PCB (116), and the heat sink (112) is assembled on the side of the metal PCB (116) where the PCB (111) is not disposed therein. At this time, the heat sink (112) can be assembled to contact the metal PCB (116) through a screw (118). Here, the PCB may be an FR4-PCB.

[0037] The heat generated from the power semiconductor (114) is sequentially transferred to the semiconductor case (113), metal PCB (116), and heat sink (112) and radiated into the air.

[0038] The power semiconductor (114) can be electrically connected to the PCB (111) via lead wires (14b). The power semiconductor (114) can be bonded within the semiconductor case (13) to form a package type, and the semiconductor case (13) and the metal PCB (116) can be bonded via solder (115, cream solder) with the PCB (111) in between. An opening (111a) is formed in the circuit board (111) to bond the semiconductor case (13) and the metal PCB (116) with solder (115). It is preferable to configure the width of the opening (111a) to be smaller than the width of the metal PCB (116), so that the circuit board (11) is placed in an overlapping manner between the semiconductor case (113) and the metal PCB (116).

[0039] That is, solder (115) is applied to the upper surface of the metal PCB (116), and a circuit board (111) with a semiconductor case (113) assembled thereon is mounted so that the opening (111a) aligns with it. Then, the semiconductor case (113) and the metal PCB (116) can be joined through a soldering method called reflow soldering. Accordingly, the bonding surface of the semiconductor case (113) and the metal PCB (116) becomes integrated, thereby maximizing heat transfer from the power semiconductor (114) to the metal PCB (116).

[0040] The heat sink (112) may be constructed of copper or tin, which have excellent heat transfer properties, or coated with these materials. The heat sink (112) may be provided with a plurality of heat dissipation fins to dissipate heat received from the metal PCB (116) into the air.

[0041] As illustrated in FIG. 4, according to another embodiment of the present invention, in order to increase the contact area between the heatsink (112) and the metal PCB (116), an intaglio and embossed pattern may be formed on the contact surface (117) between the heatsink (112) and the metal PCB (116). Here, the pattern may be any one of a dot pattern, a linear pattern, and a grid pattern.

[0042] Hereinafter, a method for manufacturing a power semiconductor module (100) equipped with a metal PCB according to the present invention will be described in detail with reference to FIGS. 5 to 8.

[0044] FIG. 5 is a flowchart showing a manufacturing process of a power semiconductor module according to an embodiment of the present invention, FIG. 6 is a cross-sectional view showing a printing step of a power semiconductor module according to an embodiment of the present invention, FIG. 7 is a cross-sectional view showing a mounting step of a power semiconductor module according to an embodiment of the present invention, and FIG. 8 is a cross-sectional view showing an assembly step of a power semiconductor module according to an embodiment of the present invention.

[0045] Referring to FIG. 5, the method for manufacturing a power semiconductor module (100) according to the present invention comprises a printing step (S10) of applying solder (15) to a metal PCB (116), a mounting step (S20) of mounting a semiconductor case (113) on which a power semiconductor (114) is bonded to the solder (115), a preheating step (S30) of preheating the metal PCB (116) and the semiconductor case (113), a heating step (S40) of heating them above the melting point of the solder (115), a cooling step (S50) of cooling them again, and an assembly step (S60) of assembling a heat sink (112) using a screw, and each of these steps can be performed through Surface Mount Technology (SMT) equipment used in surface mount technology.

[0046] As illustrated in FIG. 6, the printing step (S10) is a step in which a metal PCB (116) is placed on a jig device (120) provided with a recess groove (121) for mounting the metal PCB (116), and solder (115) is applied thereon using a screen printer. That is, the printing step (S10) is completed by placing the metal PCB (116) on the recess groove (121) for the metal PCB (116) formed in the jig device (120), and applying an appropriate amount of solder (115) to the upper surface of the metal PCB (116) exposed to the outside using a screen printer.

[0047] Referring to FIG. 7, in the mounting step (S20), a semiconductor case (113) to which a power semiconductor (114) is bonded is placed, and the PCB (111) with the semiconductor case (114) assembled is placed in the recess groove (121) to cover the upper surface of the metal PCB (116) through a chip mounter. At this time, the PCB (111) is mounted so that the opening (111a) corresponds to the metal PCB (116), and thereby the semiconductor case (113) that is surface-mounted on the solder (115) comes into contact. In addition, for fixing the PCB (111), guide pins (123) may be provided at both ends of the jig device (120) so that both sides of the PCB (111) pass through and are temporarily fixed.

[0048] The preheating step (S30) involves preheating the components forming the power semiconductor module (100) placed on the jig device (120) to a predetermined temperature. In this step, the temperature of both the semiconductor case (113) and the metal PCB (116) rises, preparing them for soldering. According to the prior art illustrated in FIG. 2, the components heated in the preheating step (S30) are the semiconductor case (113) and the heat sink (112). However, since the heat sink is much thicker than other components, it takes a long time to preheat. Consequently, the overall manufacturing process time of the power semiconductor module (100) increases, and problems arise where the power semiconductor (114) is exposed to heat for a long time, causing damage or degradation. To solve these problems, the present invention proposes a method in which the power semiconductor case (113) is not directly coupled to the heat sink (112), but rather the power semiconductor case (113) is coupled to the metal PCB (116) and the heat sink (112) is assembled separately. That is, since the components heated in the preheating step (S30) are a semiconductor case (113) and a metal PCB (116) that is thin and has good thermal conductivity, the effect of significantly shortening the preheating time can be obtained. Accordingly, the manufacturing time of the overall power semiconductor module (100) can be shortened, and the deterioration of the power semiconductor (114) can be prevented.

[0049] The heating step (S40) involves heating the components of the power semiconductor module (100), excluding the heat sink (112), and in this step, the cream solder (115) is melted. This heating step (S40) is performed in a reflow SMT equipment, which typically melts the solder (115) with hot air so that the metal PCB (116) and the semiconductor case (113) can be soldered together.

[0050] The cooling step (S50) cools the components forming the power semiconductor module (100), excluding the heat sink (112) that has finished the heating step (S40). As the solder (15) melted in the heating step (S4) cools, the metal PCB (116) and the semiconductor case (13) are bonded together, and at the same time, the PCB (111) is firmly fixed between the metal PCB (116) and the semiconductor case (13). After cooling is completed, these components are removed from the jig device (20), and then the assembly step (S60) is performed.

[0051] As illustrated in FIG. 8, the assembly step (S60) is a step of attaching a heat sink (112) to an integrated PCB (111), a power semiconductor case (113), and a metal PCB (116). Holes for screwing the heat sink (112) may be provided in the integrated PCB (111) and the metal PCB (116). In addition, the method of attaching the heat sink (112) can be applied without limitation, such as joining using a thermal conductive adhesive, clip joining, rivet joining, soldering compression joining, etc., in addition to screw joining.

[0053] The preferred embodiments of the present invention described above are disclosed for illustrative purposes only, and those skilled in the art with ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following claims. Explanation of the symbols

[0054] 100 : Power semiconductor module 111 : PCB 112 : Heatsink 113 : Semiconductor Case 114 : Power semiconductor 114a : Power semiconductor (14) junction (14a) 115 : Solder 116 : Metal PCB 117 : Contact surface 118 : Screw 120 : Jig device 121 : Recess Home 123 : Guide pin

Claims

Claim 1 A power semiconductor module equipped with a metal PCB comprising: a semiconductor case on which a power semiconductor is disposed; a PCB electrically connected to the power semiconductor and having an opening formed therein; a metal PCB soldered to the semiconductor case through the opening; and a heat sink assembled on one side of the metal PCB. Claim 2 A power semiconductor module equipped with a metal PCB according to claim 1, wherein the PCB is disposed between the semiconductor case and the metal PCB, and the heat sink is assembled on the side of the metal PCB where the PCB is not disposed. Claim 3 A power semiconductor module equipped with a metal PCB, characterized in that, in paragraph 2, the heatsink is assembled to contact the metal PCB through a screw. Claim 4 A power semiconductor module equipped with a metal PCB, characterized in that, in the first aspect, in order to increase the contact area between the heatsink and the metal PCB, engraved and embossed patterns are formed on the contact surface between the heatsink and the metal PCB. Claim 5 A power semiconductor module equipped with a metal PCB, characterized in that, in paragraph 4, the pattern is one of a dot pattern, a linear pattern, and a grid pattern. Claim 6 A method for manufacturing a power semiconductor module equipped with a metal PCB, comprising: a printing step of placing a metal PCB on a jig device and applying solder; a step of placing a PCB with a semiconductor case assembled thereon on the metal PCB - wherein an opening is formed in the PCB, and as the solder is exposed through the opening, the power semiconductor case comes into contact with the solder -; a preheating step of preheating the metal PCB and the semiconductor case; a heating step of heating above the melting point of the solder to melt the solder; a cooling step of cooling the molten solder to bond the metal PCB and the semiconductor case; and an assembly step of discharging the integrated PCB, power semiconductor case, and metal PCB from the jig device and joining a heat sink. Claim 7 A method for manufacturing a power semiconductor module equipped with a metal PCB, wherein, in claim 6, the heat sink is assembled to contact the metal PCB through a screw. Claim 8 A method for manufacturing a power semiconductor module equipped with a metal PCB, characterized in that, in claim 6, in order to increase the contact area between the heat sink and the metal PCB, engraved and embossed patterns are formed on the contact surface between the heat sink and the metal PCB.

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