Semiconductor module, and method for manufacturing a semiconductor module

Abstract

To improve wire bonding property while achieving reduction in a semiconductor module.SOLUTION: A semiconductor module includes a circuit board mounted with at least one semiconductor element, a case which has an opening including at least one semiconductor element when being viewed in a thickness direction of the circuit board and is composed of a resin composition, and a lead molded integrally with the case, wherein the lead has a pad part which is arranged at a position adjacent to the circumference of the opening and extends in a direction along the circumference of the opening, and a first part which extends from one end in the longitudinal direction of the pad part and has a width narrower than the pad part, and the case has a first recess adjacent to the first part on a side closer to the opening than the first part, and a first projection provided over a part of the first part.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] A semiconductor module typified by a power semiconductor module generally includes a circuit board on which semiconductor elements are mounted, a case that houses the semiconductor elements, and a plurality of leads electrically connected to the circuit board. Here, the case is made of resin. For example, as disclosed in Patent Document 1, the case may be formed by insert molding using a plurality of leads as inserts.

[0003] In Patent Document 1, the case has an opening for housing the circuit board, and at least one of the plurality of leads has a pad disposed along the periphery of the opening. A control circuit chip is disposed on the pad.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] From the perspective of miniaturization of semiconductor modules and the like, it is preferable that the distance between the pad and the periphery of the opening of the case is as small as possible. However, in the configuration described in Patent Document 1, when this distance is reduced, during the above-described insert molding, the pad is affected by the flow of the resin in the mold and contacts the molding surface of the mold. Then, when the mold is opened, a gap is formed between the pad and the resin of the molded product due to the pad being caught by the mold. If such a gap exists, when wire bonding is performed using ultrasonic waves on the control circuit chip disposed on the pad, it becomes difficult for the ultrasonic waves to be transmitted to the joint portion, resulting in a problem of deterioration in bonding properties.

[0006] In consideration of the above circumstances, one aspect of the present disclosure aims to improve wire bonding properties while achieving miniaturization of a semiconductor module.

Means for Solving the Problems

[0007] In order to solve the above problems, a semiconductor module according to a preferred aspect of the present disclosure includes a circuit board on which at least one semiconductor element is mounted, a case made of a resin composition having an opening that includes the at least one semiconductor element when viewed in the thickness direction of the circuit board, and leads integrally formed with the case. The leads are disposed at positions adjacent to the periphery of the opening and have a pad portion that extends in a direction along the periphery of the opening, and a first portion that extends from one end in the longitudinal direction of the pad portion and is narrower than the pad portion. The case has a first recess adjacent to the first portion on a side closer to the opening than the first portion, and a first protrusion provided across a part of the first portion.

[0008] A preferred embodiment of the present disclosure is a method for manufacturing a semiconductor module, comprising: a circuit board on which at least one semiconductor element is mounted; a case made of a resin composition having an opening that encompasses the at least one semiconductor element when viewed in the thickness direction of the circuit board; and leads molded integrally with the case, the method comprising: a preparation step of preparing a lead frame including the leads and a mold; and a case forming step of forming the case by insert molding using the mold, with the lead frame as an insert, wherein the leads are positioned adjacent to the periphery of the opening and have a pad portion extending in a direction along the periphery of the opening, and a first portion extending from one end of the pad portion in the longitudinal direction and narrower than the pad portion, and the molding surface of the mold has a convex first regulating portion that contacts the first portion on the side closer to the opening than the first portion, and a concave first convex molding portion that straddles a part of the first portion. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view of a semiconductor module according to the first embodiment. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] This is a plan view illustrating the arrangement and shape of the first recess, the first protrusion, the second recess, and the second protrusion in the first embodiment. [Figure 4] This is a cross-sectional view along line BB in Figure 3. [Figure 5] This is a cross-sectional view along line CC in Figure 3. [Figure 6] This is a cross-sectional view of the DD line in Figure 3. [Figure 7] This is a cross-sectional view of the EE line in Figure 3. [Figure 8] This diagram shows the flow of a semiconductor module manufacturing method according to the first embodiment. [Figure 9] This diagram illustrates the arrangement process for the preparation process and the case formation process. [Figure 10] This is a diagram illustrating the injection and solidification processes in the case formation process. [Figure 11] This is a diagram illustrating the mold release process in the case formation process. [Figure 12] This is a diagram illustrating the mold used in the case formation process. [Figure 13] This diagram illustrates the case where the first and second regulatory sections are omitted. [Figure 14] This is a plan view illustrating the arrangement and shape of the first recess, the first protrusion, the second recess, and the second protrusion in the second embodiment. [Modes for carrying out the invention]

[0010] Preferred embodiments relating to this disclosure will be described below with reference to the drawings. Note that the dimensions and scale of parts in the drawings may differ from actual dimensions as appropriate, and some parts are shown schematically for ease of understanding. Furthermore, the scope of this disclosure is not limited to these embodiments unless otherwise stated in the following description.

[0011] 1. First Embodiment 1-1. Overall configuration of the semiconductor module Figure 1 is a plan view of the semiconductor module 10 according to the first embodiment. Figure 2 is a cross-sectional view taken along line AA in Figure 1. The semiconductor module 10 is a power module such as an IGBT (Insulated Gate Bipolar Transistor) module. In the example shown in Figure 1, the semiconductor module 10 is an IPM (Intelligent Power Module) with a built-in inverter bridge circuit and control circuit. The semiconductor module 10 is used for power control in devices such as inverters or rectifiers mounted on equipment such as air conditioners, railway vehicles, automobiles, or household electrical appliances.

[0012] As shown in Figures 1 and 2, the semiconductor module 10 comprises a plurality of semiconductor elements 21 and 22, a circuit board 30, a case 40, a lead group 50, a plurality of electronic components 61, a plurality of electronic components 62 and 63, and a sealing resin 70. In Figure 1, for the sake of clarity, the sealing resin 70 is not shown. Also in Figure 1, the lead group 50 is shaded for clarity.

[0013] Below, we will first describe the general outline of each part of the semiconductor module 10 based on Figures 1 and 2. For convenience, the following explanation will use mutually orthogonal X, Y, and Z axes as appropriate. The Z axis is an axis parallel to the thickness direction of the semiconductor module 10. In the following, one direction along the X axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. One direction along the Y axis is the Y1 direction, and the direction opposite to the Y1 direction is the Y2 direction. One 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. Also, in the following, viewing along the Z axis may be referred to as a "planar view".

[0014] 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, which is either a drain electrode or a collector electrode, is provided on the back surface of the semiconductor element 21. On the other hand, an output electrode, which is either a source electrode or an emitter electrode, and a control electrode, which is a gate electrode, are provided on the front surface of the semiconductor element 21.

[0015] The semiconductor element 22 is a diode such as a FWD (Free Wheeling Diode). The back surface of the semiconductor element 22 is provided with an output electrode, which is the cathode electrode. On the other hand, the front surface of the semiconductor element 22 is provided with an input electrode, which is the anode electrode.

[0016] In the example shown in Figure 1, semiconductor elements 21 and 22 are paired, and there are six such pairs. These six pairs of semiconductor elements 21 and 22 form three half-bridge circuits. Here, the output electrode of semiconductor element 21 is electrically connected to the input electrode of the corresponding semiconductor element 22 via bonding wires (not shown). Note that the number of semiconductor elements 21 and 22 is not limited to the example shown in Figure 1 and can be arbitrary. Furthermore, semiconductor element 21 may be a semiconductor element such as an RC (Reverse-Conducting)-IGBT that has both IGBT and FWD functions. In this case, semiconductor element 22 may be omitted.

[0017] The circuit board 30 is a DCB (Direct Copper Bonding) substrate or a DBA (Direct Bonded Aluminum) substrate, etc., on which multiple semiconductor elements 21 and multiple semiconductor elements 22 are mounted. The circuit board 30 has an insulating substrate 31, a conductive layer 32 provided on the front surface of the insulating substrate 31, and a conductive layer 33 provided on the back surface of the insulating substrate 31.

[0018] The insulating substrate 31 is made of a ceramic such as aluminum nitride, aluminum oxide, or silicon nitride. The conductive layers 32 and 33 are each made of a metal such as copper or aluminum. The back surfaces of multiple semiconductor elements 21 and 22 are joined to the conductive layer 32 by a conductive bonding material such as solder. This electrically connects the back surfaces of pairs of semiconductor elements 21 and 22. The conductive layer 33 has the function of dissipating heat from the semiconductor elements 21 and 22. Note that the shape of the conductive layer 32 shown in Figure 1 is just an example and is not limited thereto.

[0019] The case 40 is a frame-shaped member that houses multiple semiconductor elements 21 and multiple semiconductor elements 22 mounted on the circuit board 30. In the example shown in Figure 1, the case 40 houses multiple semiconductor elements 21 and multiple semiconductor elements 22, as well as multiple electronic components 61, multiple electronic components 62, and electronic component 63.

[0020] The case 40 has an opening 41 in plan view that encloses a plurality of semiconductor elements 21 and a plurality of semiconductor elements 22. As shown in Figure 2, at least a portion of the circuit board 30 in the thickness direction is placed in the opening 41. The circuit board 30 is then bonded to the case 40 with an adhesive such as an epoxy adhesive or a silicone adhesive.

[0021] Here, the case 40 has a recess 42 that opens in the Z1 direction. An opening 41 is provided at the bottom of the recess 42, and a portion of the lead group 50 is arranged around the opening 41. The case 40 also has an outer shape that follows a rectangle in plan view and has four corners CR. The shape of the opening 41 in plan view is also a rectangle.

[0022] In the example shown in Figure 2, the opening 41 has a stepped surface 41a. The normal to the stepped surface 41a is oriented in the Z2 direction, and the outer edge of the front surface of the circuit board 30 is in contact with the stepped surface 41a. The inner wall surface of the opening 41 has an inclined surface that extends from the stepped surface 41a in the Z2 direction. Note that the shape of the opening 41 is not limited to the example shown in Figure 1; for example, it may be a shape of a constant width without the stepped surface 41a and the inclined surface.

[0023] Case 40 is essentially an insulator and is composed of a resin composition containing a resin such as PPS (Polyphenylene Sulfide) or PBT (Polybutylene terephthalate). The resin composition may contain inorganic fillers such as alumina or silica to improve the mechanical strength or thermal conductivity of Case 40. Case 40, composed of this resin material, is integrally molded with the lead group 50 by insert molding, using the lead group 50 as an insert. Here, the gates of the mold used for insert molding Case 40 are located near positions P1 and P2, near the two diagonal corner CRs (upper right and lower left corners) of the four corner CRs of Case 40 in Figure 1, as will be described later. The resin used in the resin composition is not limited to thermoplastic resins, but may also be a thermosetting resin.

[0024] Case 40 has a plurality of recesses 43, a plurality of protrusions 44, a plurality of recesses 45, and a plurality of protrusions 46. These are provided on the bottom surface of the recesses 42.

[0025] Each of the multiple recesses 43 is positioned adjacent to one of the multiple leads that make up the lead group 50a (the lead group 50a will be described later). As a result, the mold used during insert molding of the case 40 is provided with convex restricting portions that form the multiple recesses 43, thereby reducing misalignment of the lead group 50a.

[0026] Each of the multiple protrusions 44 is provided spanning a portion of any of the multiple leads that make up the lead group 50a. This improves the adhesion of the lead group 50a to the case 40.

[0027] Each of the multiple recesses 45 is positioned adjacent to one of the multiple leads that make up the lead group 50b (the lead group 50b will be described later). As a result, the mold used during insert molding of the case 40 is provided with convex restricting portions that form the multiple recesses 45, thereby reducing misalignment of the lead group 50b. Here, the multiple recesses 45 include a first recess 45_1 and a second recess 45_2 that are positioned adjacent to the lead 51 (the lead 51 will be described later).

[0028] Each of the multiple protrusions 46 is provided spanning a portion of any of the multiple leads that make up the lead group 50b. This improves the adhesion of the lead group 50b to the case 40. Here, the multiple protrusions 46 include a first protrusion 46_1, a second protrusion 46_2, and a third protrusion 46_3 that span a portion of the lead 51. Note that each of the multiple protrusions 46 may span multiple leads that make up the lead group 50b.

[0029] The lead group 50 is a collection of multiple leads for electrically connecting the semiconductor elements 21, 22 and the electronic components 61, 62, 63 to a substrate (not shown) on which the semiconductor module 10 is mounted. Each of the multiple leads constituting the lead group 50 has a portion that is positioned on the bottom surface of the recess 42 and penetrates the inside and outside of the case 40. The lead group 50 is made of a metal such as copper, copper alloy, aluminum, aluminum alloy, or iron alloy, and is obtained by processing a lead frame.

[0030] The lead group 50 is divided into a lead group 50a, which consists of multiple leads for electrically connecting to multiple semiconductor elements 21 and multiple semiconductor elements 22, and a lead group 50b, which consists of multiple leads for electrically connecting to multiple electronic components 61, multiple electronic components 62 and electronic components 63.

[0031] The lead group 50a includes high-potential leads, low-potential leads, and output leads. In the example shown in Figure 1, there are three low-potential leads and three output leads. Note that the arrangement of the multiple leads constituting the lead group 50a is not limited to the example shown in Figure 1.

[0032] The lead group 50b includes multiple control leads, on which multiple electronic components 61, multiple electronic components 62, and multiple electronic components 63 are mounted. Each of the electronic components 61, 62, and 63 is joined to a predetermined lead among the multiple leads constituting the lead group 50b via a conductive bonding material such as solder. Here, among the multiple leads constituting the lead group 50b, the lead 51 is the lead for mounting the multiple electronic components 61 and electronic components 63.

[0033] Each of the electronic components 61 and 63 is an electronic component such as an IC (Integrated Circuit) for driving the semiconductor element 21. In the example shown in Figure 1, three of the six semiconductor elements 21 are associated with three electronic components 61, and the other three semiconductor elements 21 are associated with electronic components 63. Electronic components 61 are electrically connected to the control electrodes of the corresponding semiconductor elements 21 via bonding wires (not shown) and control the driving of the corresponding semiconductor elements 21. Electronic components 63 are connected to each of the other three semiconductor elements 21 via bonding wires (not shown) and control the driving of the other three semiconductor elements 21.

[0034] Electronic component 62 is a diode such as a BSD (Boot Strap Diode). In the example shown in Figure 1, three electronic components 62 correspond to three electronic components 61. Electronic components 62 are electrically connected to the corresponding electronic components 61 via bonding wires (not shown).

[0035] The sealing resin 70 is a potting material filled into the case 40. The sealing resin 70 is composed of a thermosetting resin such as epoxy resin or silicone resin. Here, it is preferable that the sealing resin 70 contains an inorganic filler such as silica or alumina from the viewpoint of improving thermal conductivity. The sealing resin 70 may also be in gel form.

[0036] 1-2. First recess, first protrusion, second recess and second protrusion Figure 3 is a plan view illustrating the arrangement and shape of the first recess 45_1, the first protrusion 46_1, the second recess 45_2, and the second protrusion 46_2 in the first embodiment. Figure 4 is a cross-sectional view taken along line BB in Figure 3. Figure 5 is a cross-sectional view taken along line CC in Figure 3. Figure 6 is a cross-sectional view taken along line DD in Figure 3. Figure 7 is a cross-sectional view taken along line EE in Figure 3.

[0037] As shown in Figure 3, the lead 51 has a pad portion 51a, a first portion 51b, a second portion 51c, a pad portion 51d, and a third portion 51e.

[0038] The pad portion 51a is positioned adjacent to the periphery of the opening 41 and is the portion of the lead 51 that extends in a direction along the periphery of the opening 41.

[0039] In the example shown in Figure 3, the pad portion 51a is located in the Y1 direction relative to the opening 41 and extends along the X axis. The pad portion 51a also has pads 51a1, 51a2, 51a3 and narrow portions 51a4, 51a5. These are arranged in the order of pad 51a1, narrow portion 51a4, pad 51a2, narrow portion 51a5, and pad 51a3 in the X1 direction. Here, the widths of the narrow portions 51a4 and 51a5 are narrower than the widths of the pads 51a1, 51a2, and 51a3, respectively.

[0040] Each of the pads 51a1, 51a2, and 51a3 is a portion of the pad section 51a for mounting the electronic component 61. The narrow section 51a4 is connected to pads 51a1 and 51a2, respectively. Similarly, the narrow section 51a5 is connected to pads 51a2 and 51a3, respectively. Note that the shape of the pad section 51a is not limited to the example shown in Figure 3; for example, it may have a shape of a constant width. That is, the pad section 51a may consist of a single pad of a constant width.

[0041] As shown in Figure 4, the pad portion 51a is positioned as close as possible to the periphery of the opening 41, without being exposed from the inner wall surface of the opening 41. Here, the case 40 is provided with a thin film portion 47 located between the side surface of the pad portion 51a in the Y2 direction and the inner wall surface of the opening 41. The thickness of portion 47 is proportional to the distance d between the pad portion 51a and the periphery of the opening 41.

[0042] As shown in Figure 3, the first portion 51b is a portion of the lead 51 that extends from end E1, which is one end of the pad portion 51a in the longitudinal direction, and is narrower than the pad portion 51a. In the example shown in Figure 3, end E1 is the end of the pad portion 51a in the X1 direction. That is, end E1 is the end of the widest portion of the pad portion 51a in the X1 direction.

[0043] The second portion 51c extends from end E2, which is the other end of the pad portion 51a in the longitudinal direction, and is a portion of the lead 51 that is narrower than the pad portion 51a. In the example shown in Figure 3, end E2 is the end of the pad portion 51a in the X2 direction. That is, end E2 is the end of the widest portion of the pad portion 51a in the X2 direction.

[0044] The width W2 of the first part 51b or the second part 51c should be narrower than the width W1 of the pad part 51a. For example, the width W2 is within the range of 0.2 times or more and 0.8 times or less of the width W1. Also, the width W2 of the first part 51b or the second part 51c should be greater than or equal to the thickness T of the lead 51, which will be described later.

[0045] The pad portion 51d is the lead portion 51 for mounting the electronic component 63 and is electrically connected to the pad portion 51a via the second portion 51c. Here, the pad portion 51d is positioned adjacent to the periphery of the opening 41 and extends in a direction along the periphery of the opening 41. In the example shown in Figure 3, the pad portion 51d is located in the Y1 direction relative to the opening 41 and extends in a direction along the X axis.

[0046] The third portion 51e is the part of the lead 51 that extends from the middle of the second portion 51c in the direction opposite to the opening 41. In the example shown in Figure 3, the third portion 51e extends from the second portion 51c in the Y1 direction. The width of the third portion 51e is wider than the width W2 of the first portion 51b or the second portion 51c. However, the width of the third portion 51e may be less than or equal to the width W2 of the first portion 51b or the second portion 51c.

[0047] Near the lead 51, a first recess 45_1, a first protrusion 46_1, a second recess 45_2, a second protrusion 46_2, and a third protrusion 46_3 are provided.

[0048] To explain in more detail, the first recess 45_1 is adjacent to the first portion 51b on the side closer to the opening 41 than the first portion 51b. The first recess 45_1 is formed by the convex first restricting portion 112_1 of the mold 100 used when insert molding the case 40, as will be described later.

[0049] In the example shown in Figure 3, the first recess 45_1 is located in the Y2 direction relative to the first portion 51b. Also, in plan view, the outer edge of the first recess 45_1 and the outer edge of the first portion 51b are either touching or close to each other. In this embodiment, the first recess 45_1 forms a rectangle in plan view. However, the plan view shape of the first recess 45_1 is not limited to a rectangle; for example, it may be a curved shape such as a circle, or a polygonal shape other than a rectangle. However, from the viewpoint of reducing the contact area between the first restricting portion 112_1 and the first portion 51b described later, the length of the first recess 45_1 in the direction along the first portion 51b is length L. A To the same extent, specifically, L A It is preferable that the ratio is between 0.5 and 1.5 times.

[0050] As shown in Figure 5, the width of the first recess 45_1 is constant in the depth direction. Also, in the example shown in Figure 5, the depth D1 of the first recess 45_1 is less than the thickness T of the lead 51. Note that the depth D1 may be greater than or equal to the thickness T. Furthermore, the shape of the first recess 45_1 is not limited to a shape with a constant width in the depth direction, but may be a shape in which the width decreases towards the bottom.

[0051] As shown in Figures 3 and 6, the first protrusion 46_1 is provided spanning over a portion of the first part 51b. That is, in a plan view, the first protrusion 46_1 has a portion that overlaps with the first part 51b and a portion that does not overlap with it, and these portions are formed as a single unit. The first protrusion 46_1 is formed by the concave first protrusion molding portion 113_1 of the mold 100 used when insert molding the case 40, as will be described later.

[0052] In the examples shown in FIGS. 3 and 6, the first convex portion 46_1 has a portion that overlaps the entire width direction of the first portion 51b in a plan view. Here, the first convex portion 46_1 has a shape extending in the direction along the Y-axis. And the length of the first convex portion 46_1 along the Y-axis is larger than the width of the first portion 51b. Also, the height H1 of the first convex portion 46_1 is not particularly limited, but from the viewpoint of ensuring the mechanical strength required for the first convex portion 46_1 and making the mold release property good during the insert molding of the case 40, for example, it is 0.5 times or more and 2 times or less with respect to the thickness T of the lead 51.

[0053] In the present embodiment, from the viewpoint of suitably preventing the pad portion 51a from floating up when the case 40 is insert-molded as described later, as shown in FIG. 3, in a plan view, the first convex portion 46_1 is located between the pad portion 51a and the first concave portion 45_1. Therefore, the distance D between the first convex portion 46_1 and the end E1 of the pad portion 51a C is shorter than the distance D between the first concave portion 45_1 and the end E1 of the pad portion 51a. A

[0054] Also, from the same viewpoint, the distance between the first concave portion 45_1 and the end E1 of the pad portion 51a is D A and the length of the first convex portion 46_1 along the longitudinal direction of the pad portion 51a is L A When this is the case, it is preferable to satisfy the relationship of L A ≦D A ≦1.5×L. A

[0055] The second concave portion 45_2 is adjacent to the second portion 51c on the side closer to the opening 41 than the second portion 51c. The second concave portion 45_2 is formed by the convex second regulating portion 112_2 of the mold 100 used when the case 40 is insert-molded as described later.

[0056] ​​In the example shown in Figure 3, the second recess 45_2 is located in the Y2 direction relative to the second portion 51c. Also, in plan view, the outer edge of the second recess 45_2 and the outer edge of the second portion 51c are either touching or close to each other. Here, the second recess 45_2 forms a quadrilateral in plan view. Note that the plan view shape of the second recess 45_2 is not limited to a quadrilateral; for example, it may have a curved shape such as a semicircle, or it may be a polygon other than a quadrilateral. However, from the viewpoint of reducing the contact area between the second restricting portion 112_2 and the second portion 51c, the length of the second recess 45_2 in the direction along the second portion 51c is length L. B To the same extent, specifically, L B It is preferable that the ratio is between 0.5 and 1.5 times.

[0057] As shown in Figure 7, the second recess 45_2 opens not only to the bottom surface of the recess 42 but also to the inner wall surface of the opening 41. In the example shown in Figure 7, the depth D2 of the second recess 45_2 is less than the thickness T of the lead 51. The depth D2 may be greater than or equal to the thickness T. Furthermore, the shape of the second recess 45_2 is not limited to the example shown in Figure 7; for example, it may have a shape that becomes narrower towards the bottom.

[0058] As shown in Figure 3, the second protrusion 46_2 and the third protrusion 46_3 are each provided straddling a portion of the second portion 51c. That is, in plan view, the second protrusion 46_2 and the third protrusion 46_3 each have a portion that overlaps with the second portion 51c and a portion that does not overlap with it, and these portions are formed as a single unit. The second protrusion 46_2 is formed by the concave second protrusion molding portion 113_2 of the mold 100 used when insert molding the case 40, as will be described later. The third protrusion 46_3 is also formed by the concave third protrusion molding portion 113_3 of the mold 100 used when insert molding the case 40, as will be described later.

[0059] In the example shown in Figure 3, the second protrusion 46_2 has a portion that overlaps with the entire width of the second portion 51c in a plan view. Here, the second protrusion 46_2 has a shape that extends in the direction along the Y-axis. The length of the second protrusion 46_2 along the Y-axis is greater than the width of the second portion 51c.

[0060] In this embodiment, as will be described later, in order to effectively prevent the pad portion 51a from lifting when insert molding the case 40, the second convex portion 46_2 is located between the pad portion 51a and the second recess 45_2 in a plan view, as shown in Figure 3. Therefore, the distance D between the second convex portion 46_2 and the end E2 of the pad portion 51a is D The distance D between the second recess 45_2 and the end E2 of the pad portion 51a is B It is shorter than that.

[0061] Also, from a similar viewpoint, the distance between the second recess 45_2 and the end E2 of the pad portion 51a is D B The length of the second protrusion 46_2 along the longitudinal direction of the pad portion 51a is set to L B When L B ≤D B ≤1.5 × L B It is preferable that the relationship is satisfied.

[0062] As mentioned above, the gate of the mold used when insert molding the case 40 is located at position P1. Position P1 is near the corner CR closest to the first portion 51b among the four corners CR of the case 40. Here, the distance between the first portion 51b and the closest corner CR is shorter than the distance between the second portion 51c and the closest corner CR. Therefore, when insert molding the case 40, the first portion 51b receives a greater force from the resin composition flowing into the mold 100 from the gate than the second portion 51c. Accordingly, from the viewpoint of suitably preventing the pad portion 51a from lifting during insert molding, the distance D between the first recess 45_1 and the edge E1 of the pad portion 51a is A The distance D between the second recess 45_2 and the end E2 of the pad portion 51a is B Shorter is preferable.

[0063] 1-3. Method for Manufacturing Semiconductor Modules Figure 8 is a diagram showing the flow of the manufacturing method for the semiconductor module 10 according to the first embodiment. As shown in Figure 8, the manufacturing method for the semiconductor module 10 includes the preparation step S10 and the case formation step S20 in this order.

[0064] Preparation step S10 prepares the lead frame 500 containing the lead group 50 and the mold 100. In preparation step S10, in addition to the lead frame 500 and the mold 100, elements necessary for the case formation step S20 are prepared as appropriate.

[0065] The case formation process S20 involves forming the case 40 using a mold 100 by insert molding, with the lead frame 500 as the insert part. Specifically, as shown in Figure 8, the case formation process S20 includes the placement process S21, the injection process S22, the solidification process S23, and the demolding process S24 in that order.

[0066] The placement step S21 involves placing the lead frame 500 into the mold 100. The injection step S22 involves injecting the resin composition into the mold 100. The solidification step S23 involves solidifying the resin composition in the mold 100 to obtain the case 40. The demolding step S24 involves removing the case 40 from the mold 100. After the case formation step S20 described above, the semiconductor module 10 is obtained by assembling the obtained case 40 and other components of the semiconductor module 10 other than the case 40 using known methods. The preparation step S10 and the case formation step S20 will be described in detail below.

[0067] Figure 9 is a diagram illustrating the preparation step S10 and the placement step S21 of the case formation step S20. In the preparation step S10, the lead frame 500 and the mold 100 are prepared as shown in Figure 9.

[0068] The lead frame 500 consists of a lead group 50 and a portion other than the lead group 50. The portion of the lead frame 500 other than the lead group 50 is removed after the solidification process S23.

[0069] The mold 100 has a lower mold 110 and an upper mold 120. The lower mold 110 has a molding surface 111 for molding the front surface of the case 40 and a molding surface 114 for molding the inner wall surface of the opening 41. Here, the molding surface 111 has a plurality of restricting portions 112 and a plurality of convex portion molding portions 113. The plurality of restricting portions 112 are convex portions for molding the plurality of recesses 45 mentioned above. The plurality of convex portion molding portions 113 are recesses for molding the plurality of convex portions 46 mentioned above. On the other hand, the upper mold 120 has a molding surface 121 for molding the back surface of the case 40.

[0070] In the placement step S21, as shown in Figure 9, the lead frame 500 is placed on the molding surface 111 of the lower mold 110. Here, each of the multiple restricting portions 112 is adjacent to one of the multiple leads that make up the lead group 50. As a result, the lead frame 500 is positioned relative to the molding surface 111 by the multiple restricting portions 112.

[0071] Figure 10 is a diagram illustrating the injection process S22 and solidification process S23 of the case formation process S20. In the injection process S22, after the placement process S21 and as shown in Figure 10, the mold 100 is closed, and in that state, the aforementioned resin composition RC is injected into the mold 100 in a state softened by heating. As a result, the mold 100 is filled with the resin composition RC. At this time, the movement of the multiple leads constituting the lead group 50 is restricted by the multiple restricting parts 112.

[0072] Subsequently, in the solidification step S23, the temperature of the resin composition RC inside the mold 100 is lowered to a temperature below its softening point, thereby solidifying the resin composition RC. This results in a case 40 integrated with the lead frame 500.

[0073] Figure 11 is a diagram illustrating the demolding process S24 of the case formation process S20. In the demolding process S24, as shown in Figure 11, the mold 100 is opened and then the case 40 is removed from the mold 100. Thus, the case 40 is obtained.

[0074] Figure 12 is a diagram illustrating the mold 100 used in the case formation process S20. The mold 100 has gates (not shown) at the aforementioned positions P1 and P2. In Figure 12, the flow of the resin composition injected into the mold 100 from the gate at position P1 is indicated by a dashed arrow. In Figure 12, the shape of the lower mold 110 is shown by a solid line.

[0075] As shown in Figure 12, the plurality of restricting portions 112 include a first restricting portion 112_1 and a second restricting portion 112_2. The first restricting portion 112_1 is a convex portion of the molding surface 111 for forming the first recess 45_1 described above. The second restricting portion 112_2 is a convex portion for forming the second recess 45_2 described above. Each of the first restricting portion 112_1 and the second restricting portion 112_2 is adjacent to the lead 51 at a position downstream in the direction of flow of the resin composition from position P1.

[0076] Here, the first restricting portion 112_1 contacts the first portion 51b at a position closer to the opening 41 than the first portion 51b. Also, the second restricting portion 112_2 and the third restricting portion 112_3 each contact the second portion 51c on the side closer to the opening 41 than the second portion 51c.

[0077] The multiple protruding molded portions 113 include a first protruding molded portion 113_1, a second protruding molded portion 113_2, and a third protruding molded portion 113_3. The first protruding molded portion 113_1 is a recess for forming the aforementioned first protruding portion 46_1, and the second protruding molded portion 113_2 is a recess for forming the aforementioned second protruding portion 46_2. The third protruding molded portion 113_3 is a recess for forming the aforementioned third protruding portion 46_3. Each of the first protruding molded portion 113_1, the second protruding molded portion 113_2, and the third protruding molded portion 113_3 straddles a portion of the lead 51.

[0078] Here, the first protruding molding portion 113_1 straddles a portion of the first portion 51b. The second protruding molding portion 113_2 and the third protruding molding portion 113_3 each straddle a portion of the second portion 51c.

[0079] In injection step S22, the lead 51 is subjected to a force from the resin composition at position P1 in a direction toward the molding surface 114 of the mold 100. Here, the first part 51b is closer to position P1 than the second part 51c, and is therefore more susceptible to the force from the resin composition at position P1.

[0080] Thus, in the case forming process S20, the resin composition RC is injected into the mold 100 with the first restricting portion 112_1 and the second restricting portion 112_2 restricting the movement of the lead 51. Here, the first restricting portion 112_1 and the second restricting portion 112_2 each restrict the movement of the lead 51 toward the molding surface 114. Therefore, even if the aforementioned force acts on the lead 51, the pad portion 51a is prevented from coming into contact with the molding surface 114. As a result, the lifting of the pad portion 51a is prevented. Although not shown in the figures, the lifting of the pad portion 51d is also prevented, similar to the pad portion 51a.

[0081] Furthermore, by positioning the first convex molding section 113_1 near the first restricting section 112_1, even if the first restricting section 112_1 comes into contact with the first portion 51b, the first convex portion 46_1 formed by the first convex molding section 113_1 prevents the first portion 51b from lifting up when the mold is opened. Similarly, by positioning the second convex molding section 113_2 near the second restricting section 112_2, even if the second restricting section 112_2 comes into contact with the second portion 51c, the second convex portion 46_2 formed by the second convex molding section 113_2 prevents the second portion 51c from lifting up when the mold is opened. Here, the third convex molding section 113_3 also prevents the second portion 51c from lifting up when the mold is opened, similar to the second convex molding section 113_2.

[0082] Figure 13 is a diagram illustrating the case where the first restricting portion 112_1 and the second restricting portion 112_2 are omitted. In this case, the lead 51 is deformed by a force from the resin composition at position P1 toward the molding surface 114 of the mold 100. As a result, the pad portion 51a comes into contact with the molding surface 114. Consequently, the pad portion 51a lifts up when the mold is opened. Note that Figure 13 shows the state in which the lead 51 comes into contact with the molding surface 114 at position PX of the corner of the molding surface 114.

[0083] As described above, the semiconductor module 10 comprises a circuit board 30, a case 40, and leads 51. The circuit board 30 mounts at least one semiconductor element 21, 22. The case 40 has an opening 41 that encloses the at least one semiconductor element 21, 22 when viewed in the thickness direction of the circuit board 30, and is made of a resin composition. The leads 51 are molded integrally with the case 40 and have a pad portion 51a and a first portion 51b. The pad portion 51a is positioned adjacent to the periphery of the opening 41 and is the portion of the leads 51 that extends in a direction along the periphery of the opening 41. The first portion 51b extends from end E1, which is one end of the pad portion 51a in the longitudinal direction, and is the portion of the leads 51 that is narrower than the pad portion 51a.

[0084] Furthermore, the case 40 has a first recess 45_1 and a first protrusion 46_1. The first recess 45_1 is adjacent to the first portion 51b on the side closer to the opening 41 than the first portion 51b. The first protrusion 46_1 is provided straddling a part of the first portion 51b.

[0085] In the semiconductor module 10 described above, the case 40 has a first recess 45_1 adjacent to the first portion 51b on the side closer to the opening 41 than the first portion 51b. Therefore, the mold 100 used when insert molding the case 40 with the lead 51 as an insert is provided with a convex first restricting portion 112_1 corresponding to the first recess 45_1. The contact between the first restricting portion 112_1 and the first portion 51b restricts the movement of the pad portion 51a toward the molding surface 114 for the opening 41 of the mold 100 during insert molding. As a result, contact between the pad portion 51a and the molding surface 114 for the opening 41 of the mold 100 is prevented.

[0086] Furthermore, since the case 40 has a first protrusion 46_1 that straddles the first portion 51b, the first protrusion 46_1 prevents the first portion 51b from lifting up due to contact between the first regulating portion 112_1 and the first portion 51b when the mold is opened. As a result, the lifting of the pad portion 51a is effectively prevented when the mold is opened.

[0087] From the above, it is possible to prevent the pad portion 51a from lifting even if the distance d between the pad portion 51a and the periphery of the opening 41 of the case 40 is shortened. Therefore, it is possible to improve wire bonding performance while miniaturizing the semiconductor module 10.

[0088] Here, the method for manufacturing the semiconductor module 10 includes a preparation step S10 for preparing a lead frame 500 including leads 51 and a mold 100, and a case forming step S20 for forming a case 40 by insert molding using the mold 100 with the lead frame 500 as the insert part. The molding surface 111 of the mold 100 has a convex first restricting portion 112_1 that contacts the first portion 51b on the side closer to the opening 41 than the first portion 51b, and a concave first convex molding portion 113_1 that is provided spanning over a part of the first portion 51b. With the above manufacturing method, it is possible to improve wire bonding performance while miniaturizing the semiconductor module 10.

[0089] In this embodiment, as described above, the distance D between the first protrusion 46_1 and the end E1 of the pad portion 51a is C The distance D between the first recess 45_1 and the end E1 of the pad portion 51a is A It is shorter than the first recess 45_1. Therefore, compared to a configuration where the first recess 45_1 is located closer to the pad portion 51a than the first protrusion 46_1, this configuration has the advantage of making it easier to prevent the pad portion 51a from lifting up due to contact between the first portion 51b and the first restricting portion 112_1 when the mold is opened.

[0090] Furthermore, as mentioned above, the distance between the first recess 45_1 and the end E1 of the pad portion 51a is D A The length of the first protrusion 46_1 along the longitudinal direction of the pad portion 51a is set to L AWhen L A ≤D A ≤1.5 × L A It satisfies the relationship.

[0091] L A ≤D A By satisfying this relationship, the lifting of the pad portion 51a caused by contact between the first restricting portion 112_1 and the first portion 51b during mold opening is effectively prevented. Also, L A ≤D A By satisfying the relationship, the distance D between the first protrusion 46_1 and the end E1 of the pad portion 51a is C The distance D between the first recess 45_1 and the end E1 of the pad portion 51a. A It can be made shorter than D A ≤1.5 × L A By satisfying this relationship, contact between the pad portion 51a and the molding surface 114 for the opening 41 of the mold 100 is effectively prevented.

[0092] Furthermore, as described above, the lead 51 has a second portion 51c. The second portion 51c extends from end E2, which is the other end of the pad portion 51a in the longitudinal direction, and is a portion of the lead 51 that is narrower than the pad portion 51a. In addition, the case 40 has a second recess 45_2 and a second protrusion 46_2. The second recess 45_2 is adjacent to the second portion 51c on the side closer to the opening 41 than the second portion 51c. The second protrusion 46_2 is provided straddling a portion of the second portion 51c.

[0093] In the above embodiment, the mold 100 used for insert molding is provided with a convex second restricting portion 112_2 corresponding to the second recess 45_2. Similar to the first restricting portion 112_1 and the first convex portion 46_1, the second restricting portion 112_2 and the second convex portion 46_2 effectively prevent the pad portion 51a from lifting up when the mold is opened. Therefore, compared to a configuration using only the first recess 45_1 and the first convex portion 46_1, this configuration has the advantage of making it easier to prevent the pad portion 51a from lifting up when the mold is opened.

[0094] In this embodiment, as described above, the distance D between the second protrusion 46_2 and the end E2 of the pad portion 51a is D The distance D between the second recess 45_2 and the end E2 of the pad portion 51a is B It is shorter than the other. Therefore, compared to a configuration where the second recess 45_2 is located closer to the pad portion 51a than the second protrusion 46_2, this configuration has the advantage of making it easier to prevent the pad portion 51a from lifting up due to contact between the second portion 51c and the second restricting portion 112_2 when the mold is opened.

[0095] Furthermore, as mentioned above, the distance between the second recess 45_2 and the end E2 of the pad portion 51a is D B The length of the second protrusion 46_2 along the longitudinal direction of the pad portion 51a is set to L B When L B ≤D B ≤1.5 × L B It satisfies the relationship.

[0096] L B ≤D B By satisfying this relationship, the lifting of the pad portion 51a caused by contact between the second restricting portion 112_2 and the second portion 51c during mold opening is effectively prevented. Also, L B ≤D B By satisfying the relationship, the distance D between the second protrusion 46_2 and the end E2 of the pad portion 51a is D The distance D between the second recess 45_2 and the end E2 of the pad portion 51a. B It can be made shorter than D B ≤1.5 × L B By satisfying this relationship, contact between the pad portion 51a and the molding surface 114 for the opening 41 of the mold 100 is effectively prevented.

[0097] Furthermore, as mentioned above, case 40 has an outer shape that follows a rectangle in plan view, and when the corner closest to the first part 51b among the four corners of case 40 is taken as the first corner, the distance between the first part 51b and the first corner is shorter than the distance between the second part 51c and the first corner. In addition, the distance D between the first recess 45_1 and the end E1 of the pad part 51a is AThe distance D between the second recess 45_2 and the end E2 of the pad portion 51a is B It is shorter than that.

[0098] If the distance between the first portion 51b and the first corner is shorter than the distance between the second portion and the first corner, and the gate during insert molding is located near the first corner, then the first portion 51b receives greater pressure from the resin composition flowing into the mold 100 from the gate compared to the second portion 51c. Therefore, the distance D between the first recess 45_1 and the end E1 of the pad portion 51a is A The distance D between the second recess 45_2 and the end E2 of the pad portion 51a. B By making it shorter, contact between the pad portion 51a and the molding surface 114 for the opening 41 of the mold 100 is effectively prevented.

[0099] 2. Second Embodiment A second embodiment of this disclosure will be described below. For elements whose operation and function are the same as those in the above-described embodiment, the reference numerals used in the above-described embodiment will be reused, and detailed descriptions of each will be omitted as appropriate.

[0100] Figure 14 is a plan view illustrating the arrangement and shape of the first recess 45_1, the first protrusion 46_1, the second recess 45_2, and the second protrusion 46_2 in the second embodiment. This embodiment is the same as the first embodiment described above, except that the plan view shapes of the first recess 45_1 and the second recess 45_2 are different.

[0101] In this embodiment, the width of the first recess 45_1 and the second recess 45_2 along the X-axis decreases as they approach the lead 51. The plan view shape of the first recess 45_1 is circular. The plan view shape of the second recess 45_2 is semicircular.

[0102] The second embodiment described above also makes it possible to miniaturize the semiconductor module 10 while improving wire bonding performance. In this embodiment, as described above, the width along the X axis of the first recess 45_1 and the second recess 45_2 decreases as it approaches the lead 51, so the contact area between the mold portion for forming the first recess 45_1 and the second recess 45_2 and the first portion 51b can be reduced. As a result, the lifting of the pad portion 51a is suitably prevented when the mold is opened.

[0103] 3. Variant This disclosure is not limited to the embodiments described above, and various modifications are possible as described below. Furthermore, each embodiment and each modification may be combined as appropriate.

[0104] 3-1. Variation 1 In each of the above embodiments, the distance D between the first protrusion 46_1 and the end E1 of the pad portion 51a is C The distance D between the first recess 45_1 and the end E1 of the pad portion 51a is A Shorter configurations are given as examples, but the configuration is not limited to these, and the distance D C Distance D A The above may also be true. Similarly, the distance D between the second protrusion 46_2 and the end E2 of the pad portion 51a D The distance D between the second recess 45_2 and the end E2 of the pad portion 51a is B Shorter configurations are given as examples, but the configuration is not limited to these, and the distance D D Distance D B That's fine too.

[0105] 3-2. Variation 2 In the embodiments described above, a configuration having a first recess 45_1 and a second recess 45_2 is exemplified, but the invention is not limited to this configuration, and one of the first recess 45_1 and the second recess 45_2 may be omitted. If the first recess 45_1 is omitted, the second recess 45_2 corresponds to the "first recess".

[0106] 3-3. Modified Example 3 In the embodiments described above, a configuration having a first protrusion 46_1, a second protrusion 46_2, and a third protrusion 46_3 is exemplified, but the invention is not limited to this configuration. For example, one of the second protrusion 46_2 and the third protrusion 46_3 may be omitted. If the second protrusion 46_2 is omitted, the third protrusion 46_3 corresponds to the "second protrusion".

[0107] 3-4. Variation 4 In the embodiments described above, configurations are shown to prevent the pad portions 51a and 51d from lifting up. However, the invention is not limited to these configurations, and any pad portion along the opening 41 can similarly prevent lifting up. In other words, the pads to be prevented from lifting up are not limited to die pads for mounting electronic components, but may also be pads for external connections.

[0108] 3-5. Modification Example 5 In the embodiments described above, the first and second protrusions are exemplified as overlapping over the entire width of the lead 51 in a plan view. However, the invention is not limited to this configuration, and the first and second protrusions may overlap over only a portion of the lead 51 in a plan view. Furthermore, the plan view shapes of the first and second protrusions are not limited to the shapes described above and are arbitrary. In addition, the first and second protrusions may overlap not only the lead 51 but also adjacent leads in a plan view. [Explanation of Symbols]

[0109] 10...Semiconductor module, 21...Semiconductor element, 22...Semiconductor element, 30...Circuit board, 31...Insulating substrate, 32...Conducting layer, 33...Conducting layer, 40...Case, 41...Opening, 41a...Stepped surface, 42...Recess, 43...Recess, 44...Convex part, 45...Recess, 45_1...First recess, 45_2...Second recess, 46...Convex part, 46_1...First convex part, 46_2...Second convex part, 46_3...Third convex part, 47...Part, 50...Lead group, 50a...Lead group, 50b...Lead group, 51...Lead, 51a...Pad part, 51a1...Pad, 51a2...Pad, 51a3...Pad, 51a4...Narrow part, 51a5...Narrow part, 51b...First part, 51c...Second part, 51d...Pad part, 51e...Third part, 61 ...electronic component, 62...electronic component, 63...electronic component, 70...encapsulating resin, 100...mold, 110...lower mold, 111...molding surface, 112...regulating section, 112_1...first regulating section, 112_2...second regulating section, 112_3...third regulating section, 113...convex molding section, 113_1...first convex molding section, 113_2...second convex molding section, 113_3...third convex molding section, 114...molding surface, 120...upper mold, 121...molding surface, 500...lead frame, CR...angle, D1...depth, D2...depth, DA...distance, DC...distance, DD...distance, E1...end, E2...end, RC...resin composition, S10...preparation process, S20...case formation process, S21...placement process, S22...injection process, S23...solidification process, S24...release process.

Claims

1. A circuit board equipped with at least one semiconductor element, A case made of a resin composition having an opening that encloses at least one semiconductor element when viewed in the thickness direction of the circuit board, The case comprises a lead molded integrally with the case, The aforementioned lead is A pad portion is positioned adjacent to the periphery of the opening and extends in a direction along the periphery of the opening, It has a first portion that extends from one end of the pad portion in the longitudinal direction and is narrower than the pad portion, The aforementioned case is, A first recess adjacent to the first portion on the side closer to the opening than the first portion, A first protrusion is provided that straddles a portion of the first part, Semiconductor module.

2. The distance between the first protrusion and the one end of the pad portion is shorter than the distance between the first recess and the one end of the pad portion. The semiconductor module according to claim 1.

3. The distance between the first recess and the one end of the pad portion is D. Ａ The length of the first protrusion along the longitudinal direction of the pad portion is set to L. Ａ In that case, L Ａ ≤ D Ａ ≤ 1.5 × L Ａ Satisfying the relationship, The semiconductor module according to claim 1 or 2.

4. The lead extends from the other end of the pad portion in the longitudinal direction and has a second portion that is narrower than the pad portion. The aforementioned case is, A second recess adjacent to the second portion on the side closer to the opening than the second portion, A second protrusion is provided that straddles a portion of the second part, A semiconductor module according to any one of claims 1 to 3.

5. The distance between the second protrusion and the other end of the pad portion is shorter than the distance between the second recess and the other end of the pad portion. The semiconductor module according to claim 4.

6. The distance between the second recess and the other end of the pad portion is D. Ｂ The length of the second protrusion along the longitudinal direction of the pad portion is L. Ｂ In that case, L Ｂ ≤ D Ｂ ≤ 1.5 × L Ｂ satisfying the relationship of The semiconductor module according to claim 4 or 5.

7. The aforementioned case has an outer shape that follows a rectangle when viewed from above. Of the four corners of the aforementioned case, when the corner closest to the first part is designated as the first corner, The distance between the first part and the first angle is shorter than the distance between the second part and the first angle. The distance between the first recess and one end of the pad portion is shorter than the distance between the second recess and the other end of the pad portion. A semiconductor module according to any one of claims 4 to 6.

8. A circuit board equipped with at least one semiconductor element, A case made of a resin composition having an opening that encloses at least one semiconductor element when viewed in the thickness direction of the circuit board, A method for manufacturing a semiconductor module comprising a lead molded integrally with the case, A preparation step of preparing a lead frame and mold including the aforementioned leads, The process includes a case forming step of forming the case by insert molding using the mold described above, with the lead frame as the insert part, The aforementioned lead is A pad portion is positioned adjacent to the periphery of the opening and extends in a direction along the periphery of the opening, It has a first portion that extends from one end of the pad portion in the longitudinal direction and is narrower than the pad portion, The molded surface of the aforementioned type is A convex first restricting portion that contacts the first portion on the side closer to the opening than the first portion, A concave first convex molding portion is provided spanning a portion of the first part, A method for manufacturing semiconductor modules.

9. In the case forming step, the resin composition is injected into the mold while the first restricting portion restricts the movement of the lead. A method for manufacturing a semiconductor module according to claim 8.

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