Semiconductor module and method for manufacturing semiconductor module

Abstract

The invention relates to a semiconductor module and a manufacturing method of the semiconductor module. A semiconductor module having excellent reliability can be easily manufactured. The semiconductor module includes: a substrate on which a semiconductor element is mounted; a frame-shaped case that surrounds the substrate; a lead terminal penetrating the housing from the inside to the outside; and a bonding wire that electrically connects the semiconductor element and the lead terminal in the case, the lead terminal having a pad portion disposed in the case, and the case having: a first surface that is bonded to the pad portion; and a second surface that is bonded to the substrate by means of an adhesive and faces in the opposite direction to the first surface, and a groove that faces the pad portion from the substrate is provided in the inner peripheral surface of the case over the entire range from the first surface to the second surface.

Description

Technical Field

[0001] The present disclosure relates to a semiconductor module and a method for manufacturing the semiconductor module. Background Art

[0002] Semiconductor modules represented by power semiconductor modules generally include: a substrate for mounting semiconductor elements; a resin case for housing the semiconductor elements; and a plurality of lead terminals electrically connected to the semiconductor elements via bonding wires. For example, in Patent Documents 1 to 3, a plurality of lead terminals are bonded to the case by insert molding.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-201611

[0006] Patent Document 2: Japanese Patent Application Publication No. 2023-31941

[0007] Patent Document 3: Japanese Patent Application Publication No. 2016-111028 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] If the housing is formed by insert molding, the close fit between the lead terminal and the housing is poor, so a gap may be formed between the pad portion of the lead terminal and the housing in the housing. If such a gap exists, when the pad portion of the lead terminal is wire-bonded using ultrasound, transmission loss of the ultrasound occurs due to resonance of the pad portion, which may reduce the bonding performance of the wire bonding.

[0010] In order to solve this problem, a countermeasure of filling the gap between the pad portion of the lead terminal and the housing with an adhesive is considered. However, in the structures described in Patent Documents 1 to 3, a separate process for this countermeasure is required when manufacturing the semiconductor module, which complicates the manufacturing process.

[0011] In view of the above circumstances, an object of one aspect of the present disclosure is to easily manufacture a semiconductor module with excellent reliability.

[0012] Solutions for solving problems

[0013] In order to solve the above problems, the semiconductor module of the preferred technical solution of the present invention comprises: a substrate, which is used to mount a semiconductor element; a frame-shaped shell, which surrounds the substrate; a lead terminal, which penetrates the shell from the inside to the outside; and a bonding wire, which electrically connects the semiconductor element to the lead terminal in the shell, and the lead terminal has a pad portion arranged in the shell, and the shell has: a first surface, which is bonded to the pad portion; and a second surface, which is bonded to the substrate by an adhesive and faces in a direction opposite to the first surface, and a groove from the substrate toward the pad portion is provided on the inner circumferential surface of the shell over the entire range from the first surface to the second surface.

[0014] In a method for manufacturing a semiconductor module of a preferred technical solution of the present disclosure, the semiconductor module comprises: a substrate for mounting a semiconductor element; a frame-shaped housing composed of a resin composition and surrounding the substrate; a lead terminal penetrating the housing from the inside to the outside; and a bonding wire electrically connecting the semiconductor element to the lead terminal in the housing, wherein the method for manufacturing a semiconductor module comprises: a molding step of forming the housing integrally with a lead frame including the lead terminal by insert molding; and a bonding step of bonding the substrate to the housing by an adhesive, the lead terminal having a pad portion arranged in the housing, the housing having: a first surface bonded to the pad portion; and a second surface bonded to the substrate by the adhesive and facing in a direction opposite to the first surface, a groove from the substrate toward the pad portion being provided on the inner peripheral surface of the housing over the entire range from the first surface to the second surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a top view of the semiconductor module according to the embodiment.

[0016] Figure 2 yes Figure 1 AA line section view in.

[0017] Figure 3 This is a rear view of the semiconductor module according to the embodiment.

[0018] Figure 4 This is a rear view of the housing.

[0019] Figure 5 It is a diagram for explaining the bonding state between the housing and the substrate.

[0020] Figure 6 This is a flowchart showing a method for manufacturing a semiconductor module according to an embodiment.

[0021] Figure 7 It is a diagram for explaining the arrangement process in the forming process.

[0022] Figure 8 It is a diagram for explaining the injection process in the molding process.

[0023] Fig. 9 It is a diagram for explaining the curing step in the molding step.

[0024] Fig.10 It is a figure for demonstrating the demolding process in a molding process.

[0025] Fig.11 It is a diagram for explaining the joining process.

[0026] Fig.12 This is a diagram for explaining the installation process.

[0027] Fig.13 It is a diagram for explaining the wire bonding process.

[0028] Description of Reference Numerals

[0029] 10. semiconductor module; 21. semiconductor element; 22. semiconductor element; 30. substrate; 31. insulating substrate; 32. conductor pattern; 40. housing; 41. opening; 41a. groove; 42. recess; 43. recess; 50. terminal group; 50a. terminal group; 50b. terminal group; 51. lead terminal; 51a. pad; 52. lead terminal; 52a. pad; 53. lead terminal; 53a. pad; 61. electronic component; 62. electronic component; 70. sealing resin; 100. mold; 110. lower mold; 111. molding surface; 112. recess; 120. Upper mold; 121, molding surface; 122, molding surface; 122a, convex portion; 123, gate; 500, lead frame; AD, adhesive; ADO, adhesive; BW1, bonding wire; BW2, bonding wire; D, depth; F1, first surface; F2, second surface; RC, resin composition; S10, molding process; S11, configuration process; S12, injection process; S13, curing process; S14, demolding process; S20, bonding process; S30, installation process; S40, lead bonding process; Wa, width; Wb1, width; Wb2, width; Wb3, width; Wc, width. DETAILED DESCRIPTION

[0030] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, in the accompanying drawings, the size and scale of each part are appropriately different from the actual one, and there are also parts schematically shown for easy understanding. In addition, as long as there is no record of the meaning of the present disclosure being particularly limited in the following description, the scope of the present disclosure is not limited to these embodiments.

[0031] 1. Implementation Method

[0032] 1-1. Overall structure of semiconductor module

[0033] Figure 1 It is a plan view of the semiconductor module 10 according to the embodiment. Figure 2 yes Figure 1 AA line section view in. Figure 3 1 is a rear view of a semiconductor module 10 according to an embodiment. The semiconductor module 10 is a power module such as an IGBT (Insulated Gate Bipolar Transistor) module. Figures 1 to 3 In the example shown, the semiconductor module 10 is an IPM (Intelligent Power Module) having an inverter bridge circuit and a control circuit built in. The semiconductor module 10 is used for power control in devices such as inverters and rectifiers mounted on air conditioners, railway vehicles, automobiles, or household electrical appliances.

[0034] like Figures 1 to 3 As shown, the semiconductor module 10 includes a plurality of semiconductor elements 21, a plurality of semiconductor elements 22, a substrate 30, a housing 40, a terminal group 50 including lead terminals 51, 52, and 53, a plurality of electronic components 61, an electronic component 62, bonding wires BW1, BW2, and a sealing resin 70. Figure 1 In the figure, for the convenience of explanation, the sealing resin 70 is omitted. Figure 1 and Figure 3 In FIG. 1 , the terminal group 50 is represented by grid lines for easy viewing.

[0035] Below, first, based on Figures 1 to 3 , the general conditions of each part of the semiconductor module 10 are described in sequence. In addition, the following description is appropriately carried out using mutually orthogonal X-axis, Y-axis and Z-axis for convenience. The Z-axis is an axis parallel to the thickness direction of the semiconductor module 10. In the following, a direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. A direction along the Y-axis is the Y1 direction, and the direction opposite to the Y1 direction is the Y2 direction. A direction along the Z-axis is the Z1 direction, and the direction opposite to the Z1 direction is the Z2 direction. The relationship between these directions and the vertical direction is not particularly limited and is arbitrary. In addition, in the following, observation in the direction along the Z-axis is sometimes referred to as "looking down".

[0036] The semiconductor element 21 is a switching element such as an IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET (metal-oxide-semiconductor field-effect transistor). An input electrode serving as a drain electrode or a collector is provided on the back of the semiconductor element 21. On the other hand, an output electrode serving as a source electrode or an emitter and a control electrode serving as a gate are provided on the front of the semiconductor element 21.

[0037] The semiconductor element 22 is a diode such as a FWD (Free Wheeling Diode). An output electrode serving as a cathode is provided on the back surface of the semiconductor element 22. On the other hand, an input electrode serving as an anode is provided on the front surface of the semiconductor element 22.

[0038] exist Figure 1 In the example shown, the semiconductor element 21 and the semiconductor element 22 form a pair, and the number of pairs is 6. Moreover, the 6 pairs of semiconductor elements 21 and semiconductor elements 22 constitute 3 sets of half-bridge circuits. Here, the output electrode of the semiconductor element 21 is electrically connected to the input electrode of the paired semiconductor element 22 via a bonding wire (not shown). In addition, the number of semiconductor elements 21 and semiconductor elements 22 is not limited to Figure 1 The examples shown are arbitrary. In addition, the semiconductor element 21 may be a semiconductor element such as an RC (Reverse-Conducting)-IGBT having both the functions of an IGBT and a FWD. In this case, the semiconductor element 22 may be omitted.

[0039] The substrate 30 is a substrate such as a DCB (Direct Copper Bonding) substrate or a DBA (Direct Bonded Aluminum) substrate for mounting a plurality of semiconductor elements 21 and a plurality of semiconductor elements 22. The substrate 30 includes an insulating substrate 31 and a conductor pattern 32 provided on the front surface of the insulating substrate 31.

[0040] The insulating substrate 31 is made of ceramics such as aluminum nitride, aluminum oxide, or silicon nitride. The conductor pattern 32 is made of metal such as copper or aluminum. Figure 1 In the example shown, the conductor pattern 32 is divided into four parts. Three of the four parts are each joined to a pair of semiconductor elements 21 and the back surface of the semiconductor element 22 using a conductive bonding material such as solder. The remaining one of the four parts is joined to three pairs of semiconductor elements 21 and the back surface of the semiconductor element 22 using a conductive bonding material such as solder. In addition, Figure 1The shape of the conductor pattern 32 shown is an example and is not limited thereto. In addition, a metal plate may be provided on the back of the insulating substrate 31. The metal plate is made of the same material as the conductor pattern 32, for example, and has the function of dissipating heat from the semiconductor elements 21 and 22.

[0041] The housing 40 is a frame-shaped member surrounding the substrate 30 and accommodates the plurality of semiconductor elements 21 and the plurality of semiconductor elements 22 mounted on the substrate 30. Figure 1 In the illustrated example, the housing 40 accommodates a plurality of electronic components 61 and 62 in addition to the plurality of semiconductor elements 21 and the plurality of semiconductor elements 22 .

[0042] The housing 40 has an opening 41 that includes the plurality of semiconductor elements 21 and the plurality of semiconductor elements 22 when viewed from above. Figure 2 As shown, the housing 40 has a recessed portion 42 opened toward the Z1 direction and a recessed portion 43 opened toward the Z2 direction. The opening 41 is opened at the bottom surface of the recessed portion 42 and the bottom surface of the recessed portion 43 .

[0043] The bottom surface of the recess 42 constitutes the first surface F1. Part of the terminal group 50 is bonded to the first surface F1. The bottom surface of the recess 43 constitutes the second surface F2. The substrate 30 is bonded to the second surface F2 using an adhesive AD. At least a part of the substrate 30 in the thickness direction is arranged in the recess 43. In addition, the shapes of the opening 41, the recesses 42, and 43 are not limited to Figures 1 to 3 In the example shown, for example, a plan view shape other than a quadrilateral may be used, or a shape having a stepped surface or a tapered surface may be used.

[0044] The adhesive AD is an adhesive such as an epoxy adhesive or a silicone adhesive. The constituent material of the adhesive AD may also be the same material as the sealing resin 70. In this case, compared with a method in which the constituent material of the adhesive AD is different from the sealing resin 70, not only can the cost be reduced, but also there is an advantage that the adhesion between the adhesive AD and the sealing resin 70 is easily improved.

[0045] A plurality of grooves 41a are provided on the inner peripheral surface of the opening 41 and are arranged at intervals in the circumferential direction of the opening 41. Each groove 41a is a groove extending in the thickness direction (Z direction) of the shell 40, and covers the entire range from the first surface F1 to the second surface F2. Therefore, when the substrate 30 and the shell 40 are bonded together using the adhesive AD, a portion of the adhesive AD passes through the groove 41a and reaches the first surface F1. As a result, even if a gap is formed between the later-described pad portions 51a, 52a, 53a and the first surface F1 when the shell 40 is formed, a portion of the adhesive AD can be filled in the gap. Therefore, the pad portions 51a, 52a, 53a can be reliably joined to the first surface F1 without the need for an additional process. In addition, details of the groove 41a will be described later based on Figure 4 and Figure 5 Provide explanation.

[0046] The housing 40 is a substantial insulator, and is formed of a resin composition containing a thermoplastic resin such as PPS (Polyphenylene Sulfide) or PBT (Polybutylene terephthalate). From the viewpoint of improving the mechanical strength or thermal conductivity of the housing 40, the resin composition may also contain an inorganic filler such as alumina or silica. The housing 40 formed of the resin composition is integrally formed with the terminal group 50 by insert molding.

[0047] In addition, the resin used in the resin composition is not limited to thermoplastic resins, and may also be thermosetting resins. However, from the viewpoint of forming the housing 40 integrally with the lead terminals 51, 52, and 53 by simply and accurately utilizing insert molding, the housing 40 is preferably composed of a resin composition containing a thermoplastic resin. Thermoplastic resins are generally excellent in formability, but have poor adhesion to metals. Thus, in the case where the housing 40 is composed of a resin composition containing a thermoplastic resin, a gap is easily formed between the housing 40 and the pad portions 51a, 52a, and 53a after insert molding, so the effect of the present disclosure becomes significant.

[0048] The terminal group 50 is a collection of a plurality of leads for electrically connecting the semiconductor elements 21, 22 and the electronic components 61, 62 to a substrate (not shown) on which the semiconductor module 10 is mounted. The plurality of lead terminals constituting the terminal group 50 each have a portion disposed on the bottom surface of the recess 42, and penetrate the housing 40 from the inside to the outside. The terminal group 50 is made of a metal such as copper, a copper alloy, aluminum, an aluminum alloy, or an iron alloy, and is obtained by processing a lead frame.

[0049] The terminal group 50 is divided into a terminal group 50 a composed of a plurality of lead terminals 51 for main current and a terminal group 50 b composed of a plurality of lead terminals including lead terminals 52 and 53 for control signals.

[0050] The plurality of lead terminals 51 constituting the terminal group 50a include a lead terminal on the high potential side, a lead terminal on the low potential side, and a lead terminal for output. Each lead terminal 51 has a pad portion 51a bonded to the first surface F1 of the housing 40. Figure 2 As shown in FIG. 1 , one end of the bonding wire BW2 is bonded to the pad portion 51a. The other end of the bonding wire BW2 is bonded to the conductor pattern 32 of the substrate 30. In this way, the bonding wire BW2 electrically connects the semiconductor elements 21 and 22 to the lead terminal 51 in the housing 40. In addition, the shape, arrangement, and number of the plurality of leads constituting the terminal group 50a are not limited to Figure 1 Example shown.

[0051] The plurality of lead terminals constituting the terminal group 50b include lead terminals 52 and 53. The lead terminal 52 has a plurality of pad portions 52a joined to the first surface F1 of the housing 40. The electronic component 61 is joined to each pad portion 52a using a conductive bonding material (not shown) such as solder. The lead terminal 53 has a pad portion 53a joined to the first surface F1 of the housing 40. The electronic component 62 is joined to the pad portion 53a using a conductive bonding material (not shown) such as solder.

[0052] The terminal group 50 described above is integrated with the housing 40 by insert molding. Therefore, the lead terminals 51, 52, 53 are joined to the housing 40 by insert molding. Therefore, compared with the method of assembling the lead terminals 51, 52, 53 to the housing 40 after the housing 40 is formed, the work of filling the gap formed between the housing 40 and the lead terminals 51, 52, 53 except the pad portions 51a, 52a, 53a is reduced. In addition, even if a gap is formed between the housing 40 and the pad portions 51a, 52a, 53a, when the housing 40 and the substrate 30 are joined by the adhesive AD, a part of the adhesive AD can be smoothly supplied from between the housing 40 and the substrate 30 through the groove 41a to the gap. In addition, in this case, the gap is to the extent that the adhesive AD before curing produces a capillary phenomenon, so the adhesive AD can be well filled into the gap.

[0053] The electronic components 61 and 62 are electronic components such as ICs (Integrated Circuits) for driving the semiconductor element 21. Figure 1 In the example shown, three electronic components 61 correspond to three semiconductor elements 21 among the six semiconductor elements 21, and one electronic component 62 corresponds to the other three semiconductor elements 21. Figure 2 As shown, one end of a bonding wire BW1 is bonded to the control electrode of the electronic component 61. The other end of the bonding wire BW1 is bonded to the control electrode of the semiconductor element 21. In this way, the bonding wire BW1 electrically connects the semiconductor element 21 and the lead terminal 52 in the housing 40. One end of a bonding wire (not shown) is bonded to the control electrode of the electronic component 62. The other end of the bonding wire is bonded to the control electrode of the semiconductor element 21. In addition, on the terminal group 50b, in addition to mounting the electronic components 61 and 62, electronic components such as diodes such as BSD (Boot Strap Diode) can also be mounted.

[0054] The sealing resin 70 is a potting material filled in the housing 40. The sealing resin 70 is composed of a thermosetting resin such as an epoxy resin or a silicone resin. Here, from the perspective of improving thermal conductivity, the sealing resin 70 preferably contains an inorganic filler such as silicon dioxide or aluminum oxide. In addition, the sealing resin 70 may also be in a gel state.

[0055] 1-2. Inner Surface of Shell

[0056] Figure 4 It is a rear view of the housing 40 . Figure 5 4 is a diagram for explaining the bonding state between the housing 40 and the substrate 30. Figure 4 , a diagram showing the housing 40 formed integrally with the terminal group 50 as viewed in the Z1 direction. Figure 5 Shown in Figure 2 In addition, Figure 5 In the figure, for convenience of explanation, illustration of the electronic component 61, the sealing resin 70, and the bonding wire BW1 is omitted.

[0057] like Figure 4 As shown in FIG. 1 , a plurality of grooves 41 a are provided on the inner peripheral surface of the opening 41 of the housing 40 and are arranged at intervals in the circumferential direction of the opening 41. Figure 4 In the example shown, the plurality of grooves 41a are provided corresponding to the pads 51a, 52a, and 53a. Each groove 41a overlaps with any one of the pads 51a, 52a, and 53a when viewed from above. Thus, the plurality of grooves 41a include grooves 41a overlapping with the pads 51a when viewed from above, grooves 41a overlapping with the pads 52a when viewed from above, and grooves 41a overlapping with the pads 53a when viewed from above. Thus, as described later, the adhesive AD before curing can be moved toward the pads 51a, 52a, and 53a through the grooves 41a.

[0058] Here, the pads 51a, 52a, and 53a each have a rectangular shape having sides that are substantially aligned with the inner peripheral surface of the opening 41 in a plan view. As a result, compared with a configuration in which the pads 51a, 52a, and 53a have portions that are located inside the inner peripheral surface of the opening 41 in a plan view, there are advantages in that the semiconductor module 10 can be easily miniaturized and the wire routing can be easily performed when the bonding wires BW1 and BW2 are bonded to the electronic components 61 and 62 and the lead terminals 52. In addition, compared with a configuration in which there are gaps between the pads 51a, 52a, and 53a and the opening 41 in a plan view, the adhesive AD before curing can be moved toward the pads 51a, 52a, and 53a through the grooves 41a as described later.

[0059] The width Wa of the groove 41a corresponding to the pad portion 51a in the long side direction (X direction) of the housing 40 is smaller than the width Wb1 of the pad portion 51a in the long side direction (X direction) of the housing 40. The width Wa of the groove 41a corresponding to the pad portion 52a is smaller than the width Wb2 of the pad portion 52a in the length direction (X direction) of the housing 40. The width Wa of the groove 41a corresponding to the pad portion 53a is smaller than the width Wb3 of the pad portion 53a in the length direction (X direction) of the housing 40.

[0060] Thus, the width Wa of the groove 41a is smaller than the widths Wb1, Wb2, and Wb3 of the pads 51a, 52a, and 53a. Therefore, even if the adhesive AD for bonding the substrate 30 to the housing 40 is not excessively used, a portion of the adhesive AD between the housing 40 and the substrate 30 can be smoothly supplied to between the pads 51a, 52a, and 53a and the housing 40 through the groove 41a.

[0061] exist Figure 4 In the example shown, the widths Wa of the plurality of grooves 41a are equal to each other. Thus, the width Wa of each groove 41a is smaller than any one of the widths Wb1, Wb2, and Wb3. The width Wa of each groove 41a is constant between the first face F1 and the second face F2. In addition, the widths Wa of the plurality of grooves 41a may be different from each other. In addition, the number of grooves 41a corresponding to one pad portion 51a, pad portion 52a, or pad portion 53a may be more than two. The groove 41a may also be a shape in which the width Wa decreases from the second face F2 toward the first face F1.

[0062] The width Wa of the groove 41a is preferably 0.1 times or more and 0.5 times or less, and more preferably 0.2 times or more and 0.4 times or less relative to the width Wb1, the width Wb2, or the width Wb3. As a result, the adhesive AD before curing can be moved toward the pads 51a, 52a, and 53a through the groove 41a as described later. In contrast, if the width Wa is too large, the amount of adhesive AD required to move toward the pads 51a, 52a, and 53a through the groove 41a as described later is too large, and the adhesive AD tends to reach unnecessary parts. On the other hand, if the width Wa is too small, depending on the size of the gap generated between the pads 51a, 52a, and 53a and the first surface F1, it is sometimes difficult to fully fill the gap with the adhesive AD.

[0063] The depth D of the groove 41a is smaller than the width Wc of the second surface F2. The width Wc is the distance between the inner peripheral surface of the opening 41 and the side surface of the recessed portion 43. The depth D of the groove 41a is preferably 0.2 times or more and 0.8 times or less, more preferably 0.3 times or more and 0.7 times or less, and further preferably 0.4 times or more and 0.6 times or less relative to the width Wa of the groove 41a. Thus, the adhesive AD before curing can be moved toward the pads 51a, 52a, and 53a through the groove 41a as described later. In contrast, if the depth D is too large, there is a tendency that the amount of adhesive AD required to move toward the pads 51a, 52a, and 53a through the groove 41a as described later is too large. On the other hand, if the depth D is too small, it is sometimes difficult to fully fill the gap with the adhesive AD depending on the size of the gap generated between the pads 51a, 52a, and 53a and the first surface F1.

[0064] The cross-sectional shape of each groove 41a is a shape in which the width decreases toward the bottom of the groove 41a in the depth direction (Y direction). That is, therefore, the adhesive AD can be easily moved along each groove 41a. Figure 4 In the example shown, each groove 41a is a U-shaped groove. The depth D of the groove 41a is constant between the first surface F1 and the second surface F2. In addition, the cross-sectional shape of each groove 41a is not limited to Figure 4 The examples shown are arbitrary. For example, each groove 41a may be a V-shaped groove. The groove 41a may be a shape in which the depth D decreases from the second surface F2 toward the first surface F1.

[0065] like Figure 5 As shown, the housing 40 has a first surface F1 and a second surface F2 facing in the opposite direction to the first surface F1. The pads 51a, 52a, and 53a are bonded to the first surface F1. On the other hand, the substrate 30 is bonded to the second surface F2 using an adhesive AD. Figure 5, the pad portion 52a is representatively shown among the pad portions 51a, 52a, and 53a, but the relationship between the pad portions 51a, 53a and the groove 41a is the same as the relationship between the pad portion 52a and the groove 41a.

[0066] The groove 41a extends from the substrate 30 toward the pad portion 51a, the pad portion 52a, or the pad portion 53a, and covers the entire range from the first surface F1 to the second surface F2. Thus, when the housing 40 and the substrate 30 are bonded together using the adhesive AD, a portion of the adhesive AD can be smoothly supplied from between the housing 40 and the substrate 30 through the groove 41a to the gap.

[0067] 1-3. Method for manufacturing semiconductor module

[0068] Figure 6 FIG. 1 is a flowchart showing a method for manufacturing the semiconductor module 10 according to the embodiment. Figure 6 As shown, the method for manufacturing the semiconductor module 10 sequentially includes a forming step S10 , a bonding step S20 , a mounting step S30 , and a wire bonding step S40 .

[0069] In the molding step S10, the housing 40 is formed by insert molding integrally with the lead frame 500 including the lead terminals 51, 52, and 53. Specifically, the molding step S10 includes an arranging step S11, an injecting step S12, a curing step S13, and a demolding step S14 in order.

[0070] In the placement step S11, the lead frame 500 is placed with respect to the mold 100. In the injection step S12, the resin composition is injected into the mold 100. In the curing step S13, the case 40 is obtained by curing the resin composition in the mold 100. In the demolding step S14, the case 40 is removed from the mold 100.

[0071] In the bonding step S20, the substrate 30 and the housing 40 are bonded by using an adhesive AD. In the mounting step S30, the semiconductor elements 21 and 22 are mounted on the substrate 30, and the electronic components 61 and 62 are mounted on the lead frame 500. In the wire bonding step S40, bonding wires BW1 and BW2 are formed. Although not shown in the figure, after the wire bonding step S40, a sealing resin 70 is formed. In addition, after the molding step S10, unnecessary parts of the lead frame 500 are removed at an arbitrary time. Thus, the terminal group 50 is obtained. As described above, the semiconductor module 10 is obtained. Below, each process is described in detail in sequence.

[0072] Figure 7 FIG. 2 is a diagram for explaining the configuration step S11 in the forming step S10. In the configuration step S11, Figure 7 As shown, the lead frame 500 is arranged relative to the mold 100 .

[0073] The lead frame 500 is composed of a terminal group 50 and a portion other than the terminal group 50. The portion other than the terminal group 50 of the lead frame 500 is cut away at an arbitrary time after the forming step S10.

[0074] The mold 100 includes a lower mold 110 and an upper mold 120. The lower mold 110 includes a molding surface 111 for molding the front surface of the housing 40. A recess 112 is provided on the molding surface 111. In the arrangement step S11, the lead frame 500 is arranged on the molding surface 111 in a state of being fitted in the recess 112. On the other hand, the upper mold 120 includes a molding surface 121 for molding the back surface of the housing 40, a molding surface 122 for molding the inner wall surface of the opening 41, and a plurality of gates 123 for injecting the resin composition RC described later into the mold 100. A plurality of convex portions 122a for forming a plurality of grooves 41a are provided on the molding surface 122.

[0075] Figure 8 FIG. 2 is a diagram for explaining the injection step S12 in the molding step S10. In the injection step S12, as shown in FIG. Figure 8 As shown, after the mold 100 is closed, the resin composition RC as the resin composition is injected into the mold 100 in a softened state by heating. At this time, the pads 51a, 52a, 53a of the lead frame 500 are pressed toward the lower mold 110 by the protrusions 122a.

[0076] Here, as a method of pressing the pads 51a, 52a, and 53a toward the lower mold 110, it is considered to provide a fixed pin or a movable pin in the upper mold 120. However, in the method using the fixed pin, a hole is formed in the housing 40 due to the fixed pin, so after the forming step S10, a separate step for filling the hole is required for the joining step S20. In addition, in the method using the movable pin, since the movable pin is retracted before the curing step S13, the position of the pads 51a, 52a, and 53a may be offset.

[0077] Fig. 9 FIG. 2 is a diagram for explaining the curing step S13 in the forming step S10. Fig. 9 As shown, after the resin composition RC is filled into the mold 100 , the resin composition RC in the mold 100 is cooled to a temperature lower than the softening point. Thus, the resin composition RC is cured, and the housing 40 integrated with the lead frame 500 is obtained.

[0078] Fig.10 1 is a diagram for explaining the demoulding step S14 in the forming step S10. In the demoulding step S14, as shown in FIG. Fig.10 As shown, after the mold 100 is opened, the housing 40 is removed from the mold 100 .

[0079] Fig.11 FIG. 2 is a diagram for explaining the bonding step S20. Fig.11 As shown in FIG. 2 , after applying adhesive AD0 to the periphery of the second surface F2 of the recess 43, the substrate 30 is inserted into the recess 43 of the housing 40. Thus, the substrate 30 and the housing 40 are bonded by adhesive AD0. Adhesive AD0 is adhesive AD before curing, and becomes adhesive AD by curing. In the bonding step S20, as the substrate 30 is inserted into the recess 43 of the housing 40, a portion of the adhesive AD0 reaches the first surface F1 from the second surface F2 along the groove 41a.

[0080] Fig.12 FIG. 2 is a diagram for explaining the installation process S30. Fig.12 As shown, the semiconductor elements 21 and 22 are bonded to the conductor pattern 32 of the substrate 30 using a conductive bonding material such as solder, and the electronic components 61 and 62 are bonded to the pads 52a and 53a of the lead frame 500. Thus, the semiconductor elements 21 and 22 are mounted on the substrate 30, and the electronic components 61 and 62 are mounted on the lead frame 500.

[0081] Fig.13 FIG. 4 is a diagram for explaining the wire bonding step S40. Fig.13 As shown, bonding wires BW1 and BW2 are formed. In the wire bonding step S40, one end of the bonding wire BW1 is ultrasonically bonded to the control electrode on the front surface of the electronic component 61, and the other end of the bonding wire BW1 is ultrasonically bonded to the control electrode on the front surface of the semiconductor element 21. In the wire bonding step S40, one end of the bonding wire BW2 is ultrasonically bonded to the pad portion 51a, and the other end of the bonding wire BW2 is ultrasonically bonded to the conductor pattern 32 of the substrate 30.

[0082] As described above, the method for manufacturing the semiconductor module 10 includes the molding step S10 and the bonding step S20. In the molding step S10, the case 40 is integrally formed with the lead frame 500 including the lead terminals 51, 52, 53 by insert molding. In the bonding step S20, the substrate 30 and the case 40 are bonded with the adhesive AD.

[0083] In the above manufacturing method, the groove 41a is provided on the inner peripheral surface of the housing 40 from the substrate 30 toward the pads 51a, 52a, 53a over the entire range from the first surface F1 to the second surface F2. Therefore, even if a gap is formed between the pads 51a, 52a, 53a and the housing 40, when the housing 40 and the substrate 30 are bonded together using the adhesive AD, a part of the adhesive AD can be smoothly supplied from between the housing 40 and the substrate 30 through the groove 41a to the gap. Therefore, even if a gap is formed between the pads 51a, 52a, 53a and the housing 40, the pads 51a, 52a, 53a and the housing 40 can be bonded together using the adhesive AD without requiring a separate process. As a result, the semiconductor module 10 having excellent reliability can be easily manufactured.

[0084] Here, in the forming step S10, as described above, the groove 41a is formed using the mold 100 having the convex portion 122a corresponding to the groove 41a. Therefore, by using the forming step S10, the groove 41a covering the entire range from the first surface F1 to the second surface F2 can be provided on the inner peripheral surface of the housing 40. In addition, in the forming step S10, as described above, the pad portions 51a, 52a, and 53a are pressed by the convex portion 122a by reaching the first surface F1 through the convex portion 122a. Thus, the lead terminals 51, 52, and 53 can be fixed, and thus can be arranged at the desired position of the housing 40. Moreover, a hole is not formed in the housing 40 as in the method of providing a fixing pin in the mold 100. Therefore, a process for filling the hole is not required, and the reliability of the housing 40 is not reduced due to the hole.

[0085] In addition, as described above, the manufacturing method of the semiconductor module 10 includes a wire bonding step S40. The wire bonding step S40 is performed after the bonding step S20 to bond the bonding wire BW2 to the pad portion 51a, and to bond the bonding wire BW1 to the electronic components 61 and 62 on the pad portions 52a and 53a. Here, the pad portions 51a, 52a, and 53a are reliably bonded to the housing 40 by the bonding step S20, so that in the wire bonding step S40, the bonding wire BW2 can be well bonded to the pad portion 51a, and the bonding wire BW1 can be well bonded to the electronic components 61 and 62 on the pad portions 52a and 53a.

[0086] In the semiconductor module 10 described above, the groove 41a extending from the first surface F1 to the second surface F2 is provided on the inner peripheral surface of the housing 40 from the substrate 30 toward the pads 51a, 52a, 53a. Therefore, even if a gap is formed between the pads 51a, 52a, 53a and the housing 40, a part of the adhesive AD can be smoothly supplied from between the housing 40 and the substrate 30 through the groove 41a to the gap when the housing 40 and the substrate 30 are bonded using the adhesive AD. Therefore, even if a gap is formed between the pads 51a, 52a, 53a and the housing 40, the pads 51a, 52a, 53a can be bonded to the housing 40 using the adhesive AD without requiring a separate process. As a result, the semiconductor module 10 having excellent reliability can be easily manufactured.

[0087] 2. Modifications

[0088] The present disclosure is not limited to the above-described embodiments, and various modifications described below are possible. In addition, the embodiments and modifications may be appropriately combined.

[0089] 2-1. Modification 1

[0090] In the above embodiment, the semiconductor module 10 is exemplified as an IPM having the electronic components 61 and 62, but the present invention is not limited to this embodiment, and for example, the electronic components 61 and 62 may be omitted. In this case, the bonding wire BW1 is bonded to the pad portions 52a and 53a.

[0091] 2-2. Modification 2

[0092] In the above-described embodiment, the electronic components 61 and 62 are mounted on the terminal group 50 , but the present invention is not limited to this embodiment, and the electronic components 61 and 62 may be mounted on the substrate 30 as semiconductor elements.

[0093] 3. Notes

[0094] According to the above-mentioned embodiment and modification examples, for example, the following aspects can be understood.

[0095] (Supplementary Note 1) The semiconductor module of the first mode as a preferred example disclosed in the present invention comprises: a substrate for mounting a semiconductor element; a frame-shaped shell that surrounds the substrate; a lead terminal that penetrates the shell from the inside to the outside; and a bonding wire that electrically connects the semiconductor element to the lead terminal in the shell, the lead terminal having a pad portion arranged in the shell, the shell having: a first surface that is bonded to the pad portion; and a second surface that is bonded to the substrate by an adhesive and faces in a direction opposite to the first surface, and a groove is provided on the inner circumferential surface of the shell extending from the substrate toward the pad portion over the entire range from the first surface to the second surface.

[0096] According to the above method, since the grooves extending from the first surface to the second surface are provided on the inner peripheral surface of the housing from the substrate toward the pad portion, even if a gap is formed between the pad portion and the housing, when the housing and the substrate are joined using the adhesive, a part of the adhesive can be smoothly supplied from between the housing and the substrate through the grooves to the gap. Therefore, even if a gap is formed between the pad portion and the housing, the pad portion and the housing can be joined using the adhesive without requiring an additional process. As a result, a semiconductor module with excellent reliability can be easily manufactured.

[0097] (Supplementary Note 2) In a second aspect which is a preferred example of the first aspect, the cross-sectional shape of the groove is a shape in which the width decreases toward the bottom. In the above aspect, the adhesive can be easily moved along the groove.

[0098] (Supplementary Note 3) In a third aspect which is a preferred example of the first aspect or the second aspect, the width of the groove is smaller than the width of the pad portion. In the above aspect, even if the adhesive for bonding the substrate to the housing is not excessively used, a portion of the adhesive between the housing and the substrate can be smoothly supplied between the pad portion and the housing through the groove.

[0099] (Supplementary Note 4) In the fourth aspect which is a preferred example of any one of the first to third aspects, the lead terminal is joined to the housing by insert molding. In the above aspect, compared with the aspect in which the lead terminal is assembled to the housing after the housing is molded, the work of filling the gap formed between the housing and the lead terminal except the pad portion with adhesive is reduced. In addition, even if a gap is formed between the housing and the pad portion, when the housing is joined to the substrate by the adhesive, a part of the adhesive can be smoothly supplied to the gap through the groove from between the housing and the substrate. In addition, in this case, the gap is to the extent that the capillary phenomenon of the adhesive before curing occurs, so the adhesive can be better filled into the gap.

[0100] (Supplementary Note 5) In the fifth embodiment, which is a preferred example of any one of the first to fourth embodiments, the housing is composed of a resin composition containing a thermoplastic resin. In the above embodiment, the housing and the lead terminal can be formed integrally by insert molding simply and with high precision. Thermoplastic resins generally have excellent moldability, but poor adhesion to metals. Therefore, in the case where the housing is composed of a resin composition containing a thermoplastic resin, a gap is easily formed between the housing and the pad portion after insert molding, so the effect of the present disclosure becomes significant.

[0101] (Supplementary Note 6) In the manufacturing method of a semiconductor module of the sixth mode as a preferred example of the present disclosure, the semiconductor module comprises: a substrate for mounting a semiconductor element; a frame-shaped shell composed of a resin composition and surrounding the substrate; a lead terminal penetrating the shell from the inside to the outside; and a bonding wire electrically connecting the semiconductor element to the lead terminal in the shell, wherein the manufacturing method of the semiconductor module comprises: a molding step of forming the shell integrally with a lead frame including the lead terminal by embedded molding; and a bonding step of bonding the substrate to the shell by an adhesive, the lead terminal having a pad portion arranged in the shell, the shell having: a first surface bonded to the pad portion; and a second surface bonded to the substrate by the adhesive and facing in a direction opposite to the first surface, a groove from the substrate toward the pad portion being provided on the inner peripheral surface of the shell over the entire range from the first surface to the second surface.

[0102] According to the above method, since the grooves extending from the first surface to the second surface are provided on the inner peripheral surface of the housing from the substrate toward the pad portion, even if a gap is formed between the pad portion and the housing, when the housing and the substrate are joined using the adhesive, a part of the adhesive can be smoothly supplied from between the housing and the substrate through the grooves to the gap. Therefore, even if a gap is formed between the pad portion and the housing, the pad portion and the housing can be joined using the adhesive without requiring an additional process. As a result, a semiconductor module with excellent reliability can be easily manufactured.

[0103] (Supplementary Note 7) In the seventh embodiment, which is a preferred example of the sixth embodiment, in the forming process, the groove is formed using a mold having a convex portion corresponding to the groove. In the above embodiment, the forming process can be used to provide a groove that covers the entire range from the first surface to the second surface on the inner peripheral surface of the housing. In addition, during the forming process, the pad portion of the lead terminal is pressed by the convex portion, so that the lead terminal can be arranged at a desired position of the housing. Moreover, a hole is not formed in the housing as in the method of providing a fixing pin in the mold. Therefore, there is no need for a process for filling the hole, and there is no reduction in the reliability of the housing caused by the hole.

[0104] (Supplementary Note 8) In an eighth aspect which is a preferred example of the seventh aspect, in the molding step, the protrusion reaches the first surface, thereby pressing the land portion with the protrusion. In the above aspect, the lead terminal can be arranged at a desired position of the housing.

[0105] (Supplementary Note 9) In the ninth aspect which is a preferred example of any one of the sixth to eighth aspects, the method for manufacturing the semiconductor module further includes a wire bonding step in which, after the bonding step, the bonding wire is bonded to the pad portion or the electronic component on the pad portion. In the above aspects, the bonding wire can be appropriately bonded to the pad portion or the electronic component on the pad portion.

Claims

1. A semiconductor module, wherein: The semiconductor module has: A substrate for mounting semiconductor elements; a frame-shaped housing surrounding the substrate; a lead terminal penetrating the housing from the inside toward the outside; and a bonding wire that electrically connects the semiconductor element and the lead terminal in the housing, The lead terminal has a pad portion disposed in the housing. The housing has: a first surface bonded to the pad portion; and The second surface is bonded to the substrate by an adhesive and faces in a direction opposite to the first surface. A groove extending from the substrate toward the land portion is provided on the inner peripheral surface of the housing over the entire range from the first surface to the second surface.

2. The semiconductor module according to claim 1, wherein: The cross-sectional shape of the groove is a shape in which the width decreases toward the bottom of the groove.

3. The semiconductor module according to claim 1, wherein: The width of the groove is smaller than the width of the pad portion.

4. The semiconductor module according to claim 1, wherein: The lead terminal is joined to the housing by insert molding.

5. The semiconductor module according to claim 4, wherein: The housing is made of a resin composition containing a thermoplastic resin.

6. A method for manufacturing a semiconductor module, the semiconductor module comprising: A substrate for mounting semiconductor elements; a frame-shaped housing, which is made of a resin composition and surrounds the substrate; A lead terminal, which penetrates the housing from the inside toward the outside; as well as a bonding wire electrically connecting the semiconductor element and the lead terminal in the housing, wherein The method for manufacturing the semiconductor module comprises: A molding step of integrally forming the housing with a lead frame including the lead terminals by insert molding; as well as a bonding step of bonding the substrate and the housing by using an adhesive, The lead terminal has a pad portion disposed in the housing. The housing has: a first surface bonded to the pad portion; and a second surface, which is bonded to the substrate by the adhesive and faces in a direction opposite to the first surface, A groove extending from the substrate toward the land portion is provided on the inner peripheral surface of the housing over the entire range from the first surface to the second surface.

7. The method for manufacturing a semiconductor module according to claim 6, wherein: In the forming step, the groove is formed using a mold having a convex portion corresponding to the groove.

8. The method for manufacturing a semiconductor module according to claim 7, wherein: In the forming step, the land portion is pressed by the convex portion as the convex portion reaches the first surface.

9. The method for manufacturing a semiconductor module according to claim 6, wherein: The method for manufacturing a semiconductor module further includes a wire bonding step of bonding the bonding wire to the pad portion or an electronic component on the pad portion after the bonding step.

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