Semiconductor device

Abstract

To provide a semiconductor device in which the operation failure is suppressed by suppressing the separation of sealing resin due to thermal burden.SOLUTION: A semiconductor device includes a semiconductor element having an element main surface, an element back surface, and an element side surface, a lead frame on which the semiconductor element is mounted, a conductive member that electrically connects the semiconductor element and the lead frame, and sealing resin that covers a part of the lead frame and the semiconductor element. The lead frame includes a die pad, and a lead separated from the die pad. The semiconductor element is mounted on the die pad and includes a first main surface electrode formed on the element main surface. The conductive member includes a first wire that is bonded to the first main surface electrode and the lead and electrically connects the first main surface electrode and the lead. A lead side covering part that covers a joint part between the first wire and the lead is included.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a semiconductor device.

Background Art

[0002] Patent Document 1 discloses a conventional semiconductor device. The semiconductor device described in Patent Document 1 includes a semiconductor element, a lead frame, solder, a wire, and a sealing resin. In this semiconductor device, the semiconductor element is, for example, a diode chip or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) chip. The lead frame mounts the semiconductor element and conducts to the semiconductor element via solder and a wire. Solder and a wire are conductive members for conducting the lead frame and the semiconductor element. The solder is interposed between the semiconductor element and the lead frame and conducts them. The wire is joined to the semiconductor element and the lead frame and conducts them. The sealing resin covers a part of the lead frame, the semiconductor element, the solder, and the wire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A semiconductor device is subject to a thermal load, for example, due to reflow when mounted on a circuit board of an electronic device or heat generated from a semiconductor element during operation. Due to this thermal load, thermal stress concentrates at the joint between a conductive member such as solder or wire and a lead frame. Due to this concentration of thermal stress, peeling of the encapsulating resin may occur at the interface between the joint portion and the encapsulating resin. And in a situation where the encapsulating resin is peeled off, when a thermal load is applied again, for example, cracks may occur in the solder as a conductive member. Also, in the wire as a conductive member, peeling or disconnection may occur. These are causes of malfunction of the semiconductor device.

[0005] The present disclosure has been conceived in view of the above problems, and an object thereof is to provide a semiconductor device and a method for manufacturing the semiconductor device that aim to suppress malfunction by suppressing peeling of the encapsulating resin due to a thermal load.

Means for Solving the Problems

[0006] The semiconductor device provided by the first aspect of the present disclosure includes a semiconductor element having an element front surface and an element back surface spaced apart from each other in a first direction, a lead frame on which the semiconductor element is mounted, a conductive member joined to the lead frame for electrically connecting the semiconductor element and the lead frame, a resin composition covering the joint portion between the conductive member and the lead frame and exposing a part of the element front surface, and an encapsulating resin covering a part of the lead frame, the semiconductor element, and the resin composition. The resin composition has a better bonding strength with the lead frame than the bonding strength between the encapsulating resin and the lead frame, and has a better bonding strength with the conductive member than the bonding strength between the encapsulating resin and the conductive member.

[0007] In a preferred embodiment of the semiconductor device, the lead frame includes a die pad having a pad main surface facing the same direction as the main surface of the element and a pad back surface facing the same direction as the back surface of the element, and leads spaced apart from the die pad. The semiconductor element is mounted on the die pad with the pad main surface facing the back surface of the element.

[0008] In a preferred embodiment of the semiconductor device, the semiconductor element includes a back surface electrode formed on the back surface of the element. The conductive member includes a conductive bonding material that joins the semiconductor element and the die pad and electrically connects the back surface electrode and the die pad. The resin composition includes a die pad side covering portion that covers the joint portion between the conductive bonding material and the die pad.

[0009] In a preferred embodiment of the semiconductor device, the conductive bonding material has an element contact surface that contacts the back surface electrode, a die pad contact surface that contacts the die pad, and a connecting surface that connects the element contact surface and the die pad contact surface. The die pad side covering portion includes a die pad side first portion interposed between the connecting surface and the encapsulating resin.

[0010] In a preferred embodiment of the semiconductor device, the die pad side covering portion further includes a die pad side second portion that is connected to the die pad side first portion and is interposed between the pad main surface and the encapsulating resin.

[0011] In a preferred embodiment of the semiconductor device, the semiconductor element has an element side surface that connects the main surface of the element and the back surface of the element. The die pad side covering portion further includes a die pad side third portion that is connected to the die pad side first portion and is interposed between at least a part of the element side surface and the encapsulating resin.

[0012] In a preferred embodiment of the semiconductor device, the die pad side covering portion further includes a die pad side fourth portion that is connected to the die pad side third portion and is interposed between a part of the main surface of the element and the encapsulating resin.

[0013] In a preferred embodiment of the semiconductor device, the conductive bonding material is solder.

[0014] In a preferred embodiment of the semiconductor device, the back surface of the pad is exposed from the encapsulating resin.

[0015] In a preferred embodiment of the semiconductor device, the semiconductor element includes a main surface electrode formed on the main surface of the element. The conductive member includes a wire that is joined to the main surface electrode and the lead and electrically connects the main surface electrode and the lead. The resin composition includes a lead side covering portion that covers the joint portion between the wire and the lead.

[0016] In a preferred embodiment of the semiconductor device, the wire includes a first joint portion joined to the main surface electrode and a second joint portion joined to the lead. The lead side covering portion includes a lead side first portion interposed between the second joint portion and the encapsulating resin.

[0017] In a preferred embodiment of the semiconductor device, the lead side covering portion further includes a lead side second portion that is connected to the lead side first portion and is interposed between the lead and the encapsulating resin.

[0018] In a preferred embodiment of the semiconductor device, the wire further includes a linear portion that connects the first joint portion and the second joint portion. The linear portion includes a resin contact region that contacts the encapsulating resin over the entire circumference in the circumferential direction.

[0019] In a preferred embodiment of the semiconductor device, the semiconductor element is a power semiconductor chip.

[0020] A method for manufacturing a semiconductor device provided by a second aspect of the present disclosure includes a step of preparing a lead frame, a step of preparing a semiconductor element having an element front surface and an element back surface spaced apart from each other in a first direction, an element mounting step of mounting the semiconductor element on the lead frame, a conductive member forming step of joining a conductive member to the lead frame and the semiconductor element and making the lead frame and the semiconductor element conductive through the conductive member, an application step of applying a paste composition to cover a joint portion between the conductive member and the lead frame and expose a part of the element front surface, a step of drying the applied paste composition, and a step of forming a sealing resin to cover a part of the lead frame, the semiconductor element, and the dried paste composition. The paste composition contains a resin material, and the resin material has a better bonding strength with the lead frame than the bonding strength between the sealing resin and the lead frame, and a better bonding strength with the conductive member than the bonding strength between the sealing resin and the conductive member.

[0021] In a preferred embodiment of the method for manufacturing the semiconductor device, the lead frame includes a die pad having a pad front surface facing the same direction as the element front surface and a pad back surface facing the same direction as the element back surface, and leads spaced apart from the die pad. In the element mounting step, the semiconductor element is mounted on the die pad with the pad front surface and the element back surface facing each other.

[0022] In a preferred embodiment of the method for manufacturing the semiconductor device, the semiconductor element includes a back surface electrode formed on the element back surface. In the conductive member forming step, before the element mounting step, a conductive paste for joining the back surface electrode and the die pad is applied, and after the element mounting step, the conductive paste is dried to form a conductive bonding material that joins the semiconductor element and the die pad and makes the back surface electrode and the die pad conductive. In the application step, the paste composition is applied so as to cover at least the joint portion between the conductive bonding material and the die pad.

[0023] In a preferred embodiment of the method for manufacturing the semiconductor device, the semiconductor element includes a main surface electrode formed on the main surface of the element. In the conductive member forming step, after the element mounting step, a wire is formed that is joined to the main surface electrode and the lead and that electrically connects the main surface electrode and the lead. In the coating step, the paste composition is applied so as to cover at least the joint portion between the wire and the lead.

Advantages of the Invention

[0024] According to the semiconductor device of the present disclosure, peeling of the encapsulating resin due to a heat load can be suppressed, so that malfunctions can be suppressed. Further, according to the manufacturing method of the present disclosure, a semiconductor device in which malfunctions are suppressed can be manufactured.

Brief Description of the Drawings

[0025]

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Embodiments for Carrying Out the Invention

[0026] Preferred embodiments of the semiconductor device and its manufacturing method of the present disclosure will be described below with reference to the drawings.

[0027] FIGS. 1 to 10 show a semiconductor device according to the first embodiment of the present disclosure. The semiconductor device A1 of the first embodiment includes a semiconductor element 1, a lead frame 2, a plurality of wires 3, a conductive bonding material 4, a sealing resin 5, and a resin composition 6. And, among the plurality of wires 3, there are a plurality of first wires 31, second wires 32, and third wires 33.

[0028] FIG. 1 is a perspective view showing the semiconductor device A1. FIG. 2 is a view in which the sealing resin 5 and the resin composition 6 are omitted from the perspective view shown in FIG. 1. FIG. 3 is a plan view showing the semiconductor device A1. FIG. 4 is a view in which the sealing resin 5 is omitted from the plan view shown in FIG. 3. In FIG. 4, the resin composition 6 is shown by an imaginary line (for convenience of understanding, a dot pattern is added). FIG. 5 is a front view showing the semiconductor device A1. FIG. 6 is a bottom view showing the semiconductor device A1. FIG. 7 is a side view (right side) showing the semiconductor device A1. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 4. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 4. FIG. 10 is a cross-sectional view taken along line X-X of FIG. 4. For convenience of explanation, three mutually orthogonal directions are defined as the x direction, y direction, and z direction. The x direction is the left-right direction in the plan view (see FIGS. 3 and 4). The y direction is the up-down direction in the plan view (see FIGS. 3 and 4). The z direction is the thickness (height) direction of the semiconductor device A1.

[0029] The semiconductor element 1 is an electronic component that serves as the functional center of the semiconductor device A1 and is made of a semiconductor material. Such semiconductor materials include, but are not limited to, Si (silicon), SiC (silicon carbide), and GaAs (gallium arsenide). The semiconductor element 1 is, for example, a power semiconductor chip such as a MOSFET. In the present embodiment, the case where the semiconductor element 1 is a MOSFET is shown, but it is not limited thereto, and other transistors such as IGBTs (Insulated Gate Bipolar Transistors) or diodes such as Schottky barrier diodes and fast recovery diodes may also be used. In the present disclosure, the power semiconductor chip is defined as, for example, one in which the product of the voltage between the input terminal and the output terminal and the current flowing through the input terminal and the output terminal is used at approximately 1 W or more. The input terminal and the output terminal refer to the drain electrode and the source electrode, respectively, in a MOSFET. As shown in FIG. 4, the semiconductor element 1 is, for example, rectangular in plan view. As shown in FIGS. 4, 8, and 9, the semiconductor element 1 has an element main surface 1a, an element back surface 1b, and a plurality of element side surfaces 1c.

[0030] The element main surface 1a and the element back surface 1b are spaced apart in the z direction and face opposite sides of each other. Each of the plurality of element side surfaces 1c is sandwiched between the element main surface 1a and the element back surface 1b. One edge of each element side surface 1c in the z direction (the upper side in FIGS. 8 and 9) is connected to the element main surface 1a, and the other edge in the z direction (the lower side in FIGS. 8 and 9) is connected to the element back surface 1b. The element main surface 1a, the element back surface 1b, and the plurality of element side surfaces 1c are all substantially flat. In the present embodiment, the semiconductor element 1 has a pair of element side surfaces 1c facing each in the x direction and a pair of element side surfaces 1c facing each in the y direction.

[0031] As shown in FIGS. 2, 4, 8, and 9, the semiconductor element 1 includes a plurality of main surface electrodes 11 and a back surface electrode 12. Therefore, the semiconductor element 1 has a vertical structure. The plurality of main surface electrodes 11 are formed on the element main surface 1a. As shown in FIGS. 2 and 4, the plurality of main surface electrodes 11 include a first main surface electrode 111, a second main surface electrode 112, and a third main surface electrode 113. The back surface electrode 12 is formed on the element back surface 1b. The first main surface electrode 111 is a source electrode, the second main surface electrode 112 is a gate electrode, the third main surface electrode 113 is a source sense electrode, and the back surface electrode 12 is a drain electrode. Note that the arrangement, size, and shape of the first main surface electrode 111, the second main surface electrode 112, and the third main surface electrode 113 are not limited to those shown in the drawings. Also, the third main surface electrode 113 (source sense electrode) may not be particularly formed. The constituent materials of the plurality of main surface electrodes 11 (the first main surface electrode 111, the second main surface electrode 112, and the third main surface electrode 113) and the back surface electrode 12 are, for example, Al (aluminum).

[0032] The lead frame 2 mounts the semiconductor element 1 and is electrically connected to the semiconductor element 1. The lead frame 2 forms an electrical connection path between the semiconductor element 1 and a circuit board when mounted on the circuit board of an electronic device or the like. The lead frame 2 is made of a conductive material. This conductive material is, for example, Cu (copper). Note that this conductive material is not limited to Cu, and may be Ni (nickel), or a Cu alloy, a Ni alloy, a 42 alloy, or the like. The lead frame 2 is formed into an appropriate shape from a metal plate such as a rectangular Cu in plan view by punching, cutting, bending, or the like. As shown in FIGS. 2 and 4, the lead frame 2 includes a first lead 21, a second lead 22, a third lead 23, and a die pad 24. In the lead frame 2, these are spaced apart from each other.

[0033] The first lead 21 is a part of the lead frame 2 that conducts to the first main surface electrode 111 (source electrode) of the semiconductor element 1. The first lead 21 is electrically connected to the first main surface electrode 111 via the first wire 31. As shown in FIGS. 2, 4, and 8, the first lead 21 includes a wire bonding portion 211 and a plurality of terminal portions 212.

[0034] One end of each first wire 31 is joined to the wire bonding portion 211. The wire bonding portion 211 is covered with the encapsulating resin 5.

[0035] The plurality of terminal portions 212 are each connected to the wire bonding portion 211. A part of each terminal portion 212 is exposed from the encapsulating resin 5. All but one of the plurality of terminal portions 212 have the same shape. In the first lead 21, all of the plurality of terminal portions 212 may have the same shape. The plurality of terminal portions 212 overlap each other when viewed in the y direction. Each terminal portion 212 is joined to the circuit board as a source terminal of the semiconductor device A1. As shown in FIGS. 1 to 6, the first lead 21 includes five terminal portions 212. Note that the number, length, and shape of the terminal portions 212 are not limited to the illustrated examples.

[0036] The second lead 22 is a part of the lead frame 2 that conducts to the second main surface electrode 112 (gate electrode) of the semiconductor element 1. The second lead 22 is electrically connected to the second main surface electrode 112 via the second wire 32. As shown in FIGS. 2 and 4, the second lead 22 includes a wire bonding portion 221 and a terminal portion 222.

[0037] One end of the second wire 32 is joined to the wire bonding portion 221. The wire bonding portion 221 is covered with the encapsulating resin 5.

[0038] The terminal portion 222 is connected to the wire bonding portion 221. A part of the terminal portion 222 is exposed from the encapsulating resin 5. A part of the terminal portion 222 is bent at the portion exposed from the encapsulating resin 5. The terminal portion 222 overlaps a plurality of terminal portions 212 when viewed in the y direction. The terminal portion 222 is joined to the circuit board as the gate terminal of the semiconductor device A1.

[0039] The third lead 23 is a part of the lead frame 2 that conducts to the third main surface electrode 113 (source sense electrode) of the semiconductor element 1. The third lead 23 conducts to the third main surface electrode 113 via the third wire 33. As shown in FIGS. 2 and 4, the third lead 23 includes a wire bonding portion 231 and a terminal portion 232.

[0040] One end of the third wire 33 is joined to the wire bonding portion 231. The wire bonding portion 231 is covered with the encapsulating resin 5.

[0041] The terminal portion 232 is connected to the wire bonding portion 231. A part of the terminal portion 232 is exposed from the encapsulating resin 5. A part of the terminal portion 232 is bent at the portion exposed from the encapsulating resin 5. The terminal portion 232 overlaps a plurality of terminal portions 212 and the terminal portion 222 when viewed in the y direction. The terminal portion 232 is sandwiched between the plurality of terminal portions 212 and the terminal portion 222 in the x direction. The terminal portion 232 is joined to the circuit board as the source sense terminal in the semiconductor device A1.

[0042] The die pad 24 is a part of the lead frame 2 on which the semiconductor element 1 is mounted. A part of the die pad 24 is covered with the encapsulating resin 5, and the other part is exposed from the encapsulating resin 5. As shown in FIGS. 8 and 9, the die pad 24 has a pad main surface 24a and a pad back surface 24b.

[0043] The pad front surface 24a and the pad back surface 24b face opposite directions and are spaced apart in the z direction. The pad front surface 24a faces the same direction as the element front surface 1a. The pad front surface 24a faces the element back surface 1b. The pad back surface 24b faces the same direction as the element back surface 1b. The pad back surface 24b is exposed from the encapsulating resin 5.

[0044] The die pad 24 is electrically connected to the back surface electrode 12 (drain electrode) via the conductive bonding material 4. The die pad 24 is bonded to the circuit board as the drain terminal in the semiconductor device A1.

[0045] The plurality of first wires 31, second wires 32, and third wires 33 are each connection members that electrically connect the semiconductor element 1 and the lead frame 2.

[0046] The plurality of first wires 31 are bonding wires containing Al. The plurality of first wires 31 are, for example, Al alloys or pure Al to which any one of Fe (iron), Si, or Ni is added. Note that each first wire 31 may be a bonding wire containing Cu or Au (gold) instead of Al. Also, each first wire 31 may be a bonding ribbon instead of a bonding wire. In the present embodiment, the semiconductor device A1 is shown as having two first wires 31, but the number of first wires 31 is not particularly limited. The wire diameter of each first wire 31 is, for example, about φ400 μm. As shown in FIGS. 2, 4, and 8, each first wire 31 includes a first joint 311, a second joint 312, and a linear portion 313.

[0047] The first joint portion 311 is one end of each first wire 31 and is the portion joined to the first main surface electrode 111 of the semiconductor element 1. As shown in FIGS. 2, 4, and 8, the first joint portion 311 includes a front contact portion 311a, a rear contact portion 311b, and an intermediate portion 311c. Both the front contact portion 311a and the rear contact portion 311b are in contact with the first main surface electrode 111. The front contact portion 311a is located on the side farther from the second joint portion 312, and the rear contact portion 311b is located on the side closer to the second joint portion 312. The intermediate portion 311c is sandwiched between the front contact portion 311a and the rear contact portion 311b. The intermediate portion 311c is not joined to the first main surface electrode 111 and has an arched shape slightly floating from the first main surface electrode 111. In this embodiment, the first joint portion 311 contacts the first main surface electrode 111 at two locations (including the front contact portion 311a and the rear contact portion 311b), but may also contact the first main surface electrode 111 at one location.

[0048] The second joint portion 312 is the other end of each first wire 31 and is the portion joined to the wire bonding portion 211 of the first lead 21. The second joint portion 312 is covered with the resin composition 6.

[0049] The linear portion 313 is the portion connecting the first joint portion 311 and the second joint portion 312 and extends from each of the first joint portion 311 and the second joint portion 312. The linear portion 313 has a circular cross-section orthogonal to the longitudinal direction. The linear portion 313 includes a resin composition contact region 313a and a sealing resin contact region 313b. The resin composition contact region 313a is covered with the resin composition 6. The resin composition contact region 313a contacts the resin composition 6 over the entire circumference in the circumferential direction. The sealing resin contact region 313b is not covered with the resin composition 6 but is covered with the sealing resin 5. The sealing resin contact region 313b contacts the sealing resin 5 over the entire circumference in the circumferential direction.

[0050] Each first wire 31 electrically connects the first main surface electrode 111 and the first lead 21. In the semiconductor device A1, both the first wire 31 and the first main surface electrode 111 are made of a metal containing Al. Therefore, the influence of thermal stress at these bonding portions is small.

[0051] The second wire 32 is a bonding wire containing Au. Note that the second wire 32 may be a bonding wire containing Al or Cu instead of Au. The wire diameter of the second wire 32 is smaller than that of the first wire 31. That is, the second wire 32 is thinner than the first wire 31. The wire diameter of the second wire 32 is, for example, about φ50 to 75 μm. Note that the wire diameter of the second wire 32 can be appropriately changed according to the constituent material of the second wire 32. As shown in FIG. 4, the second wire 32 includes a first joint portion 321, a second joint portion 322, and a linear portion 323.

[0052] The first joint portion 321 is one end of the second wire 32 and is the portion bonded to the second main surface electrode 112 of the semiconductor element 1.

[0053] The second joint portion 322 is the other end of the second wire 32 and is the portion bonded to the wire bonding portion 221.

[0054] The linear portion 323 is the portion connecting the first joint portion 321 and the second joint portion 322 and extends from each of the first joint portion 321 and the second joint portion 322. The cross section of the linear portion 313 perpendicular to the longitudinal direction is circular.

[0055] The second wire 32 electrically connects the second main surface electrode 112 and the second lead 22.

[0056] The third wire 33 is a bonding wire containing Au. Note that the third wire 33 may be a bonding wire containing Al or Cu instead of Au. The third wire 33 is, for example, of the same quality and diameter as the second wire 32, but it may be different. Note that the wire diameter of the third wire 33 can be appropriately changed according to the constituent material of the third wire 33. As shown in FIG. 4, the third wire 33 includes a first joint 331, a second joint 332, and a linear portion 333.

[0057] The first joint 331 is one end of the third wire 33 and is the portion joined to the third main surface electrode 113 of the semiconductor element 1. Note that when the main surface electrode 11 does not include the third main surface electrode 113 (source sense electrode), by joining the first joint 331 to the first main surface electrode 111 (source electrode), it becomes possible to detect the source current.

[0058] The second joint 332 is the other end of the third wire 33 and is the portion joined to the wire bonding portion 231.

[0059] The linear portion 333 is the portion connecting the first joint 331 and the second joint 332 and extends from each of the first joint 331 and the second joint 332. The linear portion 313 has a circular cross-section orthogonal to the longitudinal direction.

[0060] The third wire 33 conductively connects the third main surface electrode 113 and the third lead 23.

[0061] The conductive bonding material 4 is for joining the semiconductor element 1 to the lead frame 2. As shown in FIGS. 8 and 9, the conductive bonding material 4 is interposed between the element back surface 1b of the semiconductor element 1 and the pad main surface 24a of the die pad 24, and electrically connects the back surface electrode 12 of the semiconductor element 1 and the die pad 24. The conductive bonding material 4 is, for example, solder. The material of the solder is not particularly limited, and examples include lead-free solder such as Sn-Sb alloy or Sn-Ag alloy, or lead-containing solder such as Sn-Pb alloy.

[0062] As shown in FIGS. 8 and 9, the conductive bonding material 4 has an element contact surface 4a, a die pad contact surface 4b, and a connecting surface 4c. The element contact surface 4a is a surface that contacts the back surface 1b of the semiconductor element 1. The element contact surface 4a is, for example, substantially flat. The die pad contact surface 4b is a surface that contacts the pad main surface 24a of the die pad 24. The die pad contact surface 4b is, for example, substantially flat. The connecting surface 4c is sandwiched between the element contact surface 4a and the die pad contact surface 4b and connects them. Note that the connecting surface 4c may be substantially flat or curved. As shown in FIGS. 8 and 9, the connecting surface 4c is inclined with respect to the element contact surface 4a and the die pad contact surface 4b. The angle formed by the element contact surface 4a and the connecting surface 4c is, for example, about 0.3 to 27°. Also, the z-direction dimension (thickness) ΔH of the conductive bonding material 4 (see FIG. 9) is, for example, about 10 to 150 μm, and each protruding dimension ΔL of the conductive bonding material 4 protruding outward from each element side surface 1c in plan view (see FIG. 9) is, for example, about 300 to 2000 μm. Note that the above-mentioned angle and each dimension ΔH, ΔL are values considering manufacturing errors and are values in the manufactured semiconductor device A1. As design values during manufacturing, the above angle is, for example, about 1 to 15°, the z-direction dimension ΔH of the conductive bonding material 4 is, for example, about 30 to 130 μm, and each protruding dimension ΔL of the conductive bonding material 4 is, for example, about 500 to 1500 μm.

[0063] The encapsulating resin 5 covers the semiconductor element 1, a part of the lead frame 2, the plurality of wires 3, and the resin composition 6. The encapsulating resin 5 is a thermosetting synthetic resin having electrical insulation properties. The encapsulating resin 5 is, for example, a black epoxy resin and contains a filler. The filler is, for example, spherical and has a particle size of, for example, about 75 μm. As shown in FIGS. 1, 3, 5 to 10, the encapsulating resin 5 has a resin main surface 5a, a resin back surface 5b, and a plurality of resin side surfaces 5c.

[0064] The resin front surface 5a and the resin back surface 5b face opposite sides and are spaced apart from each other in the z direction. The resin front surface 5a faces the same direction as the element front surface 1a, and the resin back surface 5b faces the same direction as the element back surface 1b. Each of the plurality of resin side surfaces 5c is sandwiched between the resin front surface 5a and the resin back surface 5b. One edge of each resin side surface 5c in the z direction is connected to the resin front surface 5a, and the other edge in the z direction is connected to the resin back surface 5b. In the present embodiment, the encapsulating resin 5 has a pair of resin side surfaces 5c spaced apart in the x direction and a pair of resin side surfaces 5c spaced apart in the y direction.

[0065] In the present embodiment, the first lead 21, the second lead 22, and the third lead 23 protrude from the resin side surface 5c. Also, a part of the die pad 24 protrudes from the resin side surface 5c. In a plan view, the first lead 21, the second lead 22, the third lead 23, and the die pad 24 protrude from the resin side surfaces 5c located on opposite sides of each other with the encapsulating resin 5 interposed therebetween. Further, the pad back surface 24b of the die pad 24 is exposed from the resin back surface 5b.

[0066] The resin composition 6 covers the joint portion between the conductive bonding material 4 and the die pad 24, and the joint portion between the first wire 31 and the first lead 21. The resin composition 6 has a better bonding strength with the lead frame 2 than the bonding strength between the encapsulating resin 5 and the lead frame 2. Also, the resin composition 6 has a better bonding strength with the conductive bonding material 4 than the bonding strength between the encapsulating resin 5 and the conductive bonding material 4, and has a better bonding strength with the plurality of wires 3 than the bonding strength between the encapsulating resin 5 and the plurality of wires 3. The determination of the relative quality of the bonding strength is based on, for example, the pull cup strength (unit: MPa). This pull cup strength indicates the shear strength in a state where a resin material in the shape of a pull cup (each material of the resin composition 6 and the encapsulating resin 5) is in close contact with the bonding target (each material of the lead frame 2, the conductive bonding material 4, and the plurality of wires 3). The greater the pull cup strength, the better the bonding strength, and the smaller the pull cup strength, the lower the bonding strength. The resin composition 6 is made of a material containing, for example, a thermoplastic resin, an epoxy resin, a coupling agent, a powdery inorganic filler, and a powder having rubber elasticity. The thickness of the resin composition 6 is, for example, about 10 to 20 μm. Note that the material and thickness of the resin composition 6 are not limited to those described above. As shown in FIGS. 4 and 8, the resin composition 6 includes a die pad side covering portion 61 and a lead side covering portion 62. The die pad side covering portion 61 and the lead side covering portion 62 are arranged to be separated from each other.

[0067] The die pad side covering portion 61 covers the joint portion between the conductive bonding material 4 and the die pad 24. In the following description, the joint portion is referred to as the die pad side joint portion. As shown in FIGS. 4, 8, and 9, the die pad side covering portion 61 includes a die pad side first portion 611, a die pad side second portion 612, and a die pad side third portion 613. The die pad side first portion 611, the die pad side second portion 612, and the die pad side third portion 613 are integrally formed.

[0068] As shown in FIG. 8, the die pad side first portion 611 is a portion interposed between the contact surface 4c of the conductive bonding material 4 and the encapsulating resin 5.

[0069] As shown in FIG. 8, the second part 612 on the die pad side is a part interposed between the main pad surface 24a of the die pad 24 and the encapsulating resin 5. The second part 612 on the die pad side is connected to the first part 611 on the die pad side. Specifically, the second part 612 on the die pad side is connected to the edge of the first part 611 on the die pad side in the downward direction of the z-axis. In the present embodiment, the second part 612 on the die pad side is assumed to cover at least a part of the main pad surface 24a that does not contact the die pad contact surface 4b of the conductive bonding material 4, but it may cover the entire main pad surface 24a that does not contact the die pad contact surface 4b of the conductive bonding material 4.

[0070] As shown in FIG. 8, the third part 613 on the die pad side is a part interposed between each element side surface 1c of the semiconductor element 1 and the encapsulating resin 5. The third part 613 on the die pad side is connected to the first part 611 on the die pad side. Specifically, the third part 613 on the die pad side is connected to the edge of the first part 611 on the die pad side in the upward direction of the z-axis. In the present embodiment, the third part 613 on the die pad side is arranged below the element main surface 1a in the z-axis direction when viewed in the x-axis direction or the y-axis direction.

[0071] The covering part 62 on the lead side covers the joint part between the first wire 31 and the first lead 21. In the following description, the said joint part is referred to as the joint part on the lead side. As shown in FIGS. 4 and 8, the covering part 62 on the lead side includes a first part 621 on the lead side, a second part 622 on the lead side, and a third part 623 on the lead side. The first part 621 on the lead side, the second part 622 on the lead side, and the third part 623 on the lead side are integrally formed.

[0072] As shown in FIG. 8, the first part 621 on the lead side is a part interposed between the second joint part 312 of the first wire 31 and the encapsulating resin 5.

[0073] As shown in FIG. 8, the second part 622 on the lead side is a part interposed between the wire bonding part 211 of the first lead 21 and the encapsulating resin 5. The second part 622 on the lead side is connected to the first part 621 on the lead side.

[0074] As shown in FIG. 8, the lead-side third portion 623 is a portion interposed between a part (resin composition contact region 313a) of the linear portion 313 of the first wire 31 and the sealing resin 5. Specifically, the lead-side third portion 623 is formed in a part of the linear portion 313 on the second joint portion 312 side. The lead-side third portion 623 is connected to the lead-side first portion 621.

[0075] Next, a method for manufacturing the semiconductor device A1 will be described with reference to FIGS. 11 to 13. In FIGS. 11 to 13, the same or similar elements as those shown in FIGS. 1 to 10 are denoted by the same reference numerals.

[0076] First, as shown in FIG. 11, a lead frame 200 and a semiconductor element 1 are prepared. The prepared lead frame 200 includes a first lead 21, a second lead 22, a third lead 23, and a die pad 24, which are connected by a frame frame 201. The lead frame 200 has a size capable of manufacturing, for example, a plurality of semiconductor devices A1. The semiconductor element 1 to be prepared is a MOSFET having a vertical structure, but may have a horizontal structure. On the main surface 1a of the semiconductor element 1, a first main surface electrode 111, a second main surface electrode 112, and a third main surface electrode 113 are formed, and a back surface electrode 12 is formed on the back surface 1b of the element.

[0077] Next, as shown in FIG. 12, the semiconductor element 1 is mounted on the die pad 24 via a conductive bonding material 4. In this step of mounting the semiconductor element 1 (element mounting step), a conductive paste is applied to the pad main surface 24a of the die pad 24. In the present embodiment, a solder paste is used as the conductive paste. Then, the semiconductor element 1 is placed on the applied conductive paste. At this time, the semiconductor element 1 is placed in a posture where the pad main surface 24a and the back surface 1b of the element face each other. Next, the conductive paste is fired. As a result, the conductive bonding material 4 is formed, and the semiconductor element 1 is mounted on the die pad 24. The conductive bonding material 4 electrically connects the lead frame 200 (die pad 24) and the semiconductor element 1 (back surface electrode 12).

[0078] Next, as shown in FIG. 12, a plurality of first wires 31, second wires 32, and third wires 33 are bonded to the semiconductor element 1 and the lead frame 200. For bonding each of these wires 3, a well-known wire bonder is used. In the present embodiment, the case of performing wedge bonding using a wedge tool will be described, but ball bonding using a capillary may also be used. The first wire 31 is a bonding wire whose main component is Al. The second wire 32 and the third wire 33 are bonding wires whose main component is Au. One end of the first wire 31 is bonded to the first main surface electrode 111, and the other end of the first wire 31 is bonded to the wire bonding portion 211 of the first lead 21. Also, one end of the second wire 32 is bonded to the second main surface electrode 112, and the other end of the second wire 32 is bonded to the wire bonding portion 221 of the second lead 22. Then, one end of the third wire 33 is bonded to the third main surface electrode 113, and the other end of the third wire 33 is bonded to the wire bonding portion 231 of the third lead 23. Note that the bonding order of the first wire 31, the second wire 32, and the third wire 33 is not particularly limited.

[0079] For example, the process of bonding the first wire 31 is performed as follows. First, while pressing the tip of the wedge against the first main surface electrode 111, ultrasonic vibration is applied. As a result, one end of the first wire 31 is ultrasonically melted to the first main surface electrode 111, and a forward contact portion 311a is formed. Then, while pulling out the first wire 31 from the tip of the wedge, the wedge is moved slightly, and ultrasonic vibration is applied again while pressing the tip of the wedge against the first main surface electrode 111. As a result, an intermediate portion 311c and a rear contact portion 311b are formed, and a first bonding portion 311 is formed. Subsequently, while pulling out the first wire 31 from the tip of the wedge, the wedge is moved. As a result, a linear portion 313 is formed. Subsequently, while pressing the first wire 31 against the wire bonding portion 211 of the first lead 21, ultrasonic vibration is applied. As a result, the other end of the first wire 31 is ultrasonically melted to the wire bonding portion 211. Thereafter, the wedge is moved slightly, and a cut is made in the first wire 31 with a cutter of the wedge tool. Then, together with the wedge, the first wire 31 is separated from the wire bonding portion 211, so that the first wire 31 is cut. As a result, a second bonding portion 312 is formed. Thus, one end (first bonding portion 311) of the first wire 31 is bonded to the first main surface electrode 111, the other end (second bonding portion 312) of the first wire 31 is bonded to the wire bonding portion 211, and the first main surface electrode 111 and the wire bonding portion 211 (first lead 21) are conductively connected by the first wire 31. Note that the process of bonding the second wire 32 and the third wire 33 is substantially equivalent to the process of bonding the first wire 31 described above.

[0080] Next, as shown in FIG. 13, a resin composition 6 is formed. In forming the resin composition 6, first, a paste composition is applied to the range where the resin composition 6 is to be formed. In the step of applying the paste composition (coating step), for example, it is performed using a jet dispenser. Note that instead of using a jet dispenser, other coating methods such as spray coating or spin coating may be used, or screen printing or the like may be used. In the present embodiment, in a plan view, the paste composition is applied to the surface of the conductive bonding material 4 around the semiconductor element 1. The paste composition contains at least a resin material and an organic solvent. The resin material has a better bonding strength with the lead frame 200 than the bonding strength between the encapsulating resin 5 and the lead frame 200. Also, the resin material has a better bonding strength with the plurality of wires 3 than the bonding strength between the encapsulating resin 5 and the plurality of wires 3, and has a better bonding strength with the conductive bonding material 4 than the bonding strength between the encapsulating resin 5 and the conductive bonding material 4. The paste composition in the present embodiment is made of a material containing, for example, a thermoplastic resin, an epoxy resin, a coupling agent, a powdery inorganic filler, a powder having rubber elasticity, and an organic solvent. Next, by drying the applied paste composition, the organic solvent volatilizes and a cured resin composition 6 is formed.

[0081] Next, an encapsulating resin 5 is formed. The encapsulating resin 5 is formed, for example, by mold molding using a mold. As the encapsulating resin 5, for example, an epoxy resin mixed with a granular filler is used. After forming the encapsulating resin 5, the lead frame 200 is appropriately cut and separated into individual pieces together with the semiconductor element 1. Note that before and after cutting the lead frame 200, appropriately, improvement in the strength against bending of the lead frame 2 exposed from the encapsulating resin 5, improvement in adhesiveness during mounting on a printed circuit board or the like, exterior treatment for rust prevention, etc., lead processing for bending the lead frame 2 exposed from the encapsulating resin 5 into a predetermined shape, stamping treatment for stamping the company name, product name, rod number, etc. on the encapsulating resin 5, and inspection and sorting treatment for discriminating between good and bad products are appropriately performed. Note that these treatments may be appropriately implemented according to the specifications of the final semiconductor device A1.

[0082] Through the steps shown above, the semiconductor device A1 shown in FIGS. 1 to 10 is completed.

[0083] Next, the operation and effect of the semiconductor device A1 according to the first embodiment will be described.

[0084] According to the semiconductor device A1, a resin composition 6 is provided. This resin composition 6 covers the joint portion (for example, the die pad side joint portion or the lead side joint portion) between the conductive member (for example, the conductive bonding material 4 or the first wire 31) and the lead frame 2. And the bonding strength between the resin composition 6 and the lead frame 2 is better than the bonding strength between the encapsulating resin 5 and the lead frame 2, and the bonding strength between the resin composition 6 and the conductive member is better than the bonding strength between the encapsulating resin 5 and the conductive member. By adopting this configuration, the resin composition 6 functions as an adhesive, and the bonding strength between the joint portion and the encapsulating resin 5 can be improved. Therefore, even when a thermal load is applied to the semiconductor device A1, peeling between the joint portion and the encapsulating resin 5 can be suppressed. Thereby, the semiconductor device A1 can suppress malfunction due to peeling of the encapsulating resin 5.

[0085] According to the semiconductor device A1, the element main surface 1a of the semiconductor element 1 is exposed from the resin composition 6. That is, the element main surface 1a is not covered by the resin composition 6. During the operation of the semiconductor device A1, the element main surface 1a side of the semiconductor element 1 is likely to generate heat. If the element main surface 1a is covered by the resin composition 6, when the thermal conductivity of the resin composition 6 is worse than that of the encapsulating resin 5, heat on the element main surface 1a side is likely to be trapped. Thus, the temperature difference at the interface between the resin composition 6 and the element main surface 1a becomes large. The thermal stress caused by this temperature difference may cause malfunction of the semiconductor device A1. Therefore, when the thermal conductivity of the resin composition 6 is worse than that of the encapsulating resin 5, by exposing the element main surface 1a from the resin composition 6, the temperature difference at the interface of the element main surface 1a can be made smaller than when the element main surface 1a is covered by the resin composition 6. Thereby, the semiconductor device A1 can suppress malfunction caused by the temperature difference.

[0086] According to the manufacturing method of the semiconductor device A1, the paste composition is applied by a jet dispenser. As a result, since the paste composition can be selectively applied, the resin composition 6 can be selectively formed. As shown in FIG. 13, when applying the paste composition, application to the element main surface 1a of the semiconductor element 1 can be avoided, so that the resin composition 6 to be formed can be made not to cover the element main surface 1a as shown in FIG. 4. Therefore, it is possible to manufacture the semiconductor device A1 in which the malfunction due to the above-described temperature difference is suppressed.

[0087] According to the semiconductor device A1, the resin composition 6 includes a die pad side covering portion 61, and the die pad side covering portion 61 covers the joining portion (die pad side joining portion) between the conductive bonding material 4 and the lead frame 2 (die pad 24). By adopting this configuration, the die pad side covering portion 61 can improve the bonding strength between the die pad side joining portion and the sealing resin 5, and can suppress the peeling between the die pad side joining portion and the sealing resin 5. If this peeling occurs, when a thermal load is applied to the semiconductor device A1, the thermal stress applied to the conductive bonding material 4 increases, and cracks may occur in the conductive bonding material 4. This crack causes a decrease in the heat dissipation and conductivity of the conductive bonding material 4. However, since the semiconductor device A1 can suppress the peeling between the die pad side joining portion and the sealing resin 5, it can relieve the thermal stress applied to the conductive bonding material 4 and suppress the cracks generated in the conductive bonding material 4. Therefore, the semiconductor device A1 can suppress the decrease in the heat dissipation and conductivity of the conductive bonding material 4 by suppressing the cracks in the conductive bonding material 4. Also, generally, it is known that lead-containing solder has higher physical strength against thermal stress than lead-free solder. Therefore, in conventional semiconductor devices, lead-containing solder has been tended to be used for the conductive bonding material 4 in order to improve the resistance to thermal cycles. On the other hand, in the semiconductor device A1, since the thermal stress applied to the conductive bonding material 4 can be relieved by the die pad side covering portion 61 (resin composition 6) as described above, even if lead-free solder is used for the conductive bonding material 4, the resistance to thermal cycles can be improved. For this reason, the semiconductor device A1 can improve the resistance to thermal cycles while considering environmental protection.

[0088] According to the semiconductor device A1, the die pad side covering portion 61 includes a first die pad side portion 611 interposed between the contact surface 4c of the conductive bonding material 4 and the encapsulating resin 5. By adopting this configuration, the bonding strength between the conductive bonding material 4 and the encapsulating resin 5 can be improved by the first die pad side portion 611.

[0089] FIGS. 14A and 14B are schematic diagrams for explaining the mechanism by which the bonding strength between the conductive bonding material 4 and the encapsulating resin 5 is improved by the resin composition 6 (the first die pad side portion 611). FIG. 14A shows a case where the encapsulating resin 5 is directly formed on the conductive bonding material 4, that is, a conventional semiconductor device, and FIG. 14B shows a case where the resin composition 6 is interposed between the conductive bonding material 4 and the encapsulating resin 5, that is, the semiconductor device A1 of the present disclosure.

[0090] As shown in FIG. 14A, the surface of the conductive bonding material 4 is rough due to the fine grooves 40. These grooves 40 are smaller than the particle size of the filler 51 mixed into the encapsulating resin 5. Therefore, when the encapsulating resin 5 is directly formed on the surface of the conductive bonding material 4, the filler 51 mixed into the encapsulating resin 5 may block the openings of the grooves 40, and the grooves 40 may not be filled with the encapsulating resin 5. Due to such grooves 40 not filled with the encapsulating resin 5, voids are generated at the interface between the conductive bonding material 4 and the encapsulating resin 5, and these voids cause a decrease in the bonding strength.

[0091] On the one hand, as shown in FIG. 14B, by interposing a resin composition 6 between the conductive bonding material 4 and the encapsulating resin 5, the grooves 40 on the surface of the conductive bonding material 4 are filled with the resin composition 6. Therefore, the generation of voids is suppressed by the resin composition 6, so that the decrease in bonding strength due to voids is suppressed. Further, since the resin composition 6 is filled in the grooves 40, the bonding strength with the conductive bonding material 4 is improved by the anchor effect. Furthermore, at the interface between the resin composition 6 and the encapsulating resin 5, hydrogen bonds are formed, and the bonding strength between the resin composition 6 and the encapsulating resin 5 is good due to the hydrogen bonds. From the above, by interposing the resin composition 6 between the conductive bonding material 4 and the encapsulating resin 5, the bonding strength between the conductive bonding material 4 and the encapsulating resin 5 can be increased.

[0092] According to the semiconductor device A1, the die pad side covering portion 61 includes a die pad side second portion 612 interposed between the pad main surface 24a of the die pad 24 and the encapsulating resin 5. By adopting this configuration, the bonding strength between the die pad 24 and the encapsulating resin 5 can be improved by the die pad side second portion 612. Note that the surface of the lead frame 2 also has fine grooves similar to those of the conductive bonding material 4. Therefore, the bonding strength between the die pad 24 and the encapsulating resin 5 is improved in the same principle as shown in FIGS. 14A and 14B.

[0093] According to the semiconductor device A1, the die pad side covering portion 61 includes a die pad side third portion 613 interposed between the element side surface 1c and the encapsulating resin 5. By adopting this configuration, the bonding strength between the element side surface 1c and the encapsulating resin 5 can be improved by the die pad side third portion 613. Note that the element side surface 1c also has fine grooves similar to those of the conductive bonding material 4. Therefore, the bonding strength between the element side surface 1c and the encapsulating resin 5 is improved in the same principle as shown in FIGS. 14A and 14B.

[0094] According to the semiconductor device A1, the resin composition 6 includes a lead-side covering portion 62, and the lead-side covering portion 62 covers the joint portion (lead-side joint portion) between each first wire 31 (each second joint portion 312) and the lead frame 2 (wire bonding portion 211 of the first lead 21). By adopting this configuration, the lead-side covering portion 62 can improve the bonding strength between the lead-side joint portion and the encapsulation resin 5, and can suppress the peeling between the lead-side joint portion and the encapsulation resin 5. If this peeling occurs, when a thermal load is applied to the semiconductor device A1, the thermal stress applied to the second joint portion 312 of each first wire 31 increases, and each first wire 31 may be peeled off from the wire bonding portion 211. However, since the semiconductor device A1 can suppress the peeling between the lead-side joint portion and the encapsulation resin 5, it can relieve the thermal stress applied to the second joint portion 312 of each first wire 31 and suppress each first wire 31 from being peeled off from the wire bonding portion 211. Also, when each first wire 31 is made of a metal containing Al, a passive film (oxide film) is formed on the surface of each first wire 31 and is protected from corrosion. However, when peeling occurs between the lead-side joint portion and the encapsulation resin 5, each first wire 31 and the encapsulation resin 5 may rub against each other, and the passive film on the surface of each first wire 31 may be broken. In this case, corrosion (for example, pitting corrosion) progresses from the portion where the passive film is broken, leading to a decrease in the conductivity of each first wire 31 and a disconnection of each first wire 31. On the other hand, in the semiconductor device A1, since the lead-side covering portion 62 serves as a protective material and can suppress the corrosion of the first wire 31, it can suppress a decrease in the conductivity of the first wire 31 and a disconnection of the first wire 31.

[0095] According to the semiconductor device A1, the lead-side covering portion 62 includes a lead-side first portion 621 interposed between the second joint portion 312 of the first wire 31 and the encapsulation resin 5. By adopting this configuration, the lead-side first portion 621 can improve the bonding strength between the second joint portion 312 and the encapsulation resin 5.

[0096] According to the semiconductor device A1, the lead-side covering portion 62 includes a lead-side second portion 622 interposed between the wire bonding portion 211 (first lead 21) and the sealing resin 5. By adopting this configuration, the bonding strength between the wire bonding portion 211 (first lead 21) and the sealing resin 5 can be improved by the lead-side second portion 622. Note that the surface of the lead frame 2 (first lead 21) also has fine grooves, similar to the conductive bonding material 4. Therefore, the bonding strength between the wire bonding portion 211 and the sealing resin 5 is improved in the same principle as shown in FIGS. 14A and 14B.

[0097] According to the semiconductor device A1, the lead-side covering portion 62 includes a lead-side third portion 623 interposed between a part of the linear portion 313 of the first wire 31 and the sealing resin 5. By adopting this configuration, the bonding strength between the linear portion 313 of the first wire 31 and the sealing resin 5 can be improved by the lead-side third portion 623.

[0098] According to the semiconductor device A1, each first wire 31 is made of a metal containing Al, and the first lead 21 is made of a metal containing Cu. Each first wire 31 is joined to the first lead 21 (wire bonding portion 211). In the case of joining such dissimilar metals, compared with the case of joining the same kind of metals, due to the difference in the coefficient of thermal expansion (linear expansion coefficient), the thermal stress applied to each first wire 31 (second joining portion 312) increases, and the peeling between the lead-side joining portion and the sealing resin 5 is likely to occur. Therefore, when each first wire 31 and the first lead 21 are dissimilar metals, it is more effective to suppress the peeling between the lead-side joining portion and the sealing resin 5 by including the resin composition 6 in the lead-side covering portion 62 than when each first wire 31 and the first lead 21 are the same kind of metals.

[0099] According to the semiconductor device A1, the pad back surface 24b of the die pad 24 is exposed from the encapsulating resin 5. In this way, when the die pad 24 is exposed, its expansion rate due to thermal load becomes larger than when it is not exposed. As a result, the thermal stress on the die pad side bonding portion increases, and the encapsulating resin 5 is likely to peel off at the die pad side bonding portion. Therefore, in the semiconductor device A1 where the pad back surface 24b of the die pad 24 is exposed from the encapsulating resin 5, by providing the die pad side covering portion 61, the suppression of peeling of the encapsulating resin 5 due to thermal stress on the die pad side bonding portion becomes more effective.

[0100] According to the semiconductor device A1, the semiconductor element 1 is a power semiconductor chip such as a MOSFET. Although the power semiconductor chip has high resistance to relatively large currents and voltages, it generates a large amount of heat. Therefore, peeling of the encapsulating resin 5 as described above is likely to occur. Therefore, in the semiconductor device A1 in which a power semiconductor chip is mounted as the semiconductor element 1, by providing the resin composition 6, the suppression of peeling of the encapsulating resin 5 becomes more effective.

[0101] In the first embodiment, the resin composition 6 has been shown to include both the die pad side covering portion 61 and the lead side covering portion 62, but it may include only one of them. For example, when the resin composition 6 includes only the die pad side covering portion 61, the resin composition 6 (die pad side covering portion 61) is interposed between the die pad side bonding portion and the encapsulating resin 5, thereby increasing the bonding strength between the die pad side bonding portion and the encapsulating resin 5. In this case, the step of applying the paste composition (coating step) may be performed before the step of bonding the plurality of first wires 31, second wires 32, and third wires 33. On the other hand, when the resin composition 6 includes only the lead side covering portion 62, the resin composition 6 (lead side covering portion 62) is interposed between the lead side bonding portion and the encapsulating resin 5, thereby increasing the bonding strength between the lead side bonding portion and the encapsulating resin 5. Therefore, when the resin composition 6 including only one of the die pad side covering portion 61 or the lead side covering portion 62 is formed, it is not necessary to form the other, so that cost reduction and shortening of the manufacturing process can be achieved.

[0102] In the first embodiment, the case where the lead side covering portion 62 of the resin composition 6 covers the joint portion between the first wire 31 and the first lead 21 has been shown, but the present invention is not limited thereto. For example, a resin composition 6 that covers the joint portion between the second wire 32 and the second lead 22 may be provided in place of, or in addition to, the lead side covering portion 62. By configuring in this way, it is possible to suppress the encapsulating resin 5 from peeling off from the joint portion between the second wire 32 and the second lead 22. Further, a resin composition 6 that covers the joint portion between the third wire 33 and the third lead 23 may be provided in place of, or in addition to, the lead side covering portion 62. By configuring in this way, it is possible to suppress the encapsulating resin 5 from peeling off from the joint portion between the third wire 33 and the third lead 23.

[0103] Figs. 15 to 31 show other embodiments of the semiconductor device and the method for manufacturing the same according to the present disclosure. In these figures, elements identical or similar to those of the semiconductor device A1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0104] Figures 15 and 16 show a semiconductor device according to the second embodiment. The semiconductor device A2 of the second embodiment has a different formation region of the resin composition 6 compared to the semiconductor device A1. Specifically, as shown in FIGS. 15 and 16, the resin composition 6 of the semiconductor device A2 further includes a die pad side covering portion 61 that includes a die pad side fourth portion 614. FIG. 15 is a plan view showing the semiconductor device A2 and corresponds to FIG. 4 in the first embodiment. FIG. 16 is a cross-sectional view taken along the line XVI-XVI shown in FIG. 15.

[0105] As shown in FIGS. 15 and 16, the die pad side fourth portion 614 covers a part of the element main surface 1a. The die pad side fourth portion 614 is interposed between a part of the element main surface 1a and the encapsulating resin 5. As shown in FIGS. 15 and 16, the die pad side fourth portion 614 is connected to the die pad side third portion 613. In the manufacturing process (coating process) of the semiconductor device A2, the paste composition that becomes the resin composition 6 is applied, for example, by a jet dispenser. When applying this paste composition, a part of the paste composition may be formed on the element main surface 1a. The die pad side fourth portion 614 can be formed by a part of the paste composition applied to the element main surface 1a.

[0106] According to the semiconductor device A2, similar to the semiconductor device A1, the resin composition 6 is provided. This resin composition 6 covers the joint portion (die pad side joint portion or lead side joint portion) between the conductive member (for example, the conductive bonding material 4 or the first wire 31) and the lead frame 2. Therefore, also in the semiconductor device A2, similar to the semiconductor device A1, it is possible to suppress malfunction caused by peeling of the encapsulating resin 5.

[0107] In the second embodiment, although the first joint portions 311 of the first wires 31, the first joint portions 321 of the second wires 32, and the first joint portions 331 of the third wires 33 are shown as being exposed from the die pad side covering portion 61 (resin composition 6), the present invention is not limited thereto. For example, the die pad side covering portion 61 (resin composition 6) may cover some or all of these. However, since a source current flows through each first wire 31, it tends to be at a higher temperature than the second wire 32 and the third wire 33. Therefore, each first wire 31 is more likely to be adversely affected by the heat load than the second wire 32 and the third wire 33. Thus, it is desirable to expose at least the first joint portions 331 of the first wires 31 from the die pad side covering portion 61 (resin composition 6) in terms of suppressing the adverse effects of the heat load on the first wires 31.

[0108] In the second embodiment, although the die pad side fourth portion 614 is shown as covering a part of the element main surface 1a, the present invention is not limited thereto. For example, the die pad side fourth portion 614 may cover the entire element main surface 1a. However, when the die pad side fourth portion 614 covers the entire element main surface 1a, considering that the temperature difference at the interface of the element main surface 1a becomes large as described above, it is desirable that the die pad side fourth portion 614 does not cover the entire element main surface 1a but only covers a part of the element main surface 1a.

[0109] Figs. 17 to 24 show a semiconductor device according to the third embodiment. The semiconductor device A3 of the third embodiment is different from the semiconductor device A1 mainly in that it does not include a source sense terminal.

[0110] FIG. 17 is a perspective view showing the semiconductor device A3. FIG. 18 is a view in which the encapsulating resin 5 and the resin composition 6 are omitted from the perspective view shown in FIG. 17. FIG. 19 is a plan view showing the semiconductor device A3. FIG. 20 is a view in which the encapsulating resin 5 is omitted from the plan view shown in FIG. 19. In FIG. 20, the resin composition 6 is shown by an imaginary line (marked with a dot pattern for convenience of understanding). FIG. 21 is a front view showing the semiconductor device A3. FIG. 22 is a bottom view showing the semiconductor device A3. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII of FIG. 20. FIG. 24 is a cross-sectional view taken along line XXIV-XXIV of FIG. 20.

[0111] In the semiconductor device A3, the semiconductor element 1 includes a first main surface electrode 111 and a second main surface electrode 112 as the main surface electrodes 11, as shown in FIGS. 18, 20, and 24. Therefore, the semiconductor element 1 according to the present embodiment does not include the third main surface electrode 113 as compared with the semiconductor element 1 according to the first embodiment. For this reason, the semiconductor device A3 does not include the third wire 33 and the third lead 23 that were provided to conduct the third main surface electrode 113 to the outside of the semiconductor device.

[0112] In the semiconductor device A3, the first lead 21 does not include a plurality of terminal portions 212, but includes one terminal portion 212. Note that the number of the terminal portions 212 in the semiconductor device A3 is not limited. Also, in the semiconductor device A3, as shown in FIGS. 17 to 22, the die pad 24 includes a portion protruding from the encapsulating resin 5 between the terminal portion 212 and the terminal portion 222. As shown in FIGS. 17 to 22, the protruding portion may be shorter than each of the terminal portions 212 and 222, or may have the same shape as each of the terminal portions 212 and 222.

[0113] According to the semiconductor device A3, the joint portion (die pad side joint portion or lead side joint portion) between the conductive member (conductive bonding material 4 or first wire 31) and the lead frame 2 is covered with the resin composition 6. Therefore, also in the semiconductor device A3, similar to the semiconductor device A1, it is possible to suppress the malfunction caused by the peeling of the encapsulating resin 5.

[0114] Figures 25 to 28 show a semiconductor device according to the fourth embodiment. The semiconductor device A4 of the fourth embodiment has a different formation region of the resin composition 6 compared with the semiconductor device A1. Specifically, the resin composition 6 of the semiconductor device A4 further includes a lead-side covering portion 63 and a lead-side covering portion 64. Figure 25 is a plan view showing the semiconductor device A4 and corresponds to Figure 4 in the first embodiment. Figure 26 is a partially enlarged view obtained by enlarging a part of Figure 25. Figure 27 is a cross-sectional view taken along line XXVII-XXVII of Figure 25. Figure 28 is a cross-sectional view taken along line XXVIII-XXVIII of Figure 25.

[0115] In the semiconductor device A4, it is assumed that both the second wire 32 and the third wire 33 are bonding wires containing Al. The wire diameters of the second wire 32 and the third wire 33 are, for example, about φ125 μm.

[0116] As shown in Figures 25, 26, and 27, the lead-side covering portion 63 covers the joint portion between the second wire 32 and the second lead 22. As shown in Figures 26 and 27, the lead-side covering portion 63 includes a lead-side first portion 631, a lead-side second portion 632, and a lead-side third portion 633. The lead-side first portion 631, the lead-side second portion 632, and the lead-side third portion 633 are integrally formed.

[0117] As shown in Figures 26 and 27, the lead-side first portion 631 is a portion interposed between the second joint portion 322 of the second wire 32 and the sealing resin 5.

[0118] As shown in Figures 26 and 27, the lead-side second portion 632 is a portion interposed between the wire bonding portion 221 of the second lead 22 and the sealing resin 5. The lead-side second portion 632 is connected to the lead-side first portion 631.

[0119] The lead-side third part 633 is a part interposed between a part of the linear part 323 of the second wire 32 and the sealing resin 5, as shown in FIGS. 26 and 27. Specifically, the lead-side third part 633 is formed in a part of the linear part 323 on the second joint part 322 side. The lead-side third part 633 is connected to the lead-side first part 631.

[0120] The lead-side covering part 64 covers the joint part between the third wire 33 and the third lead 23, as shown in FIGS. 25, 26, and 28. The lead-side covering part 64 includes a lead-side first part 641, a lead-side second part 642, and a lead-side third part 643, as shown in FIGS. 26 and 28. The lead-side first part 641, the lead-side second part 642, and the lead-side third part 643 are integrally formed.

[0121] The lead-side first part 641 is a part interposed between the second joint part 332 of the third wire 33 and the sealing resin 5, as shown in FIGS. 26 and 28.

[0122] The lead-side second part 642 is a part interposed between the wire bonding part 231 of the third lead 23 and the sealing resin 5, as shown in FIGS. 26 and 28. The lead-side second part 642 is connected to the lead-side first part 641.

[0123] The lead-side third part 643 is a part interposed between a part of the linear part 333 of the third wire 33 and the sealing resin 5, as shown in FIGS. 26 and 28. Specifically, the lead-side third part 643 is formed in a part of the linear part 333 on the second joint part 332 side. The lead-side third part 643 is connected to the lead-side first part 641.

[0124] According to the semiconductor device A4, similarly to the semiconductor device A1, the resin composition 6 is provided. This resin composition 6 covers the joint part (die pad side joint part or lead side joint part) between the conductive member (for example, the conductive bonding material 4 or the first wire 31) and the lead frame 2. Therefore, also in the semiconductor device A4, similarly to the semiconductor device A1, it is possible to suppress the malfunction caused by the peeling of the sealing resin 5.

[0125] According to the semiconductor device A4, the resin composition 6 includes a lead-side covering portion 63, and the lead-side covering portion 63 covers the joint portion between the second wire 32 and the second lead 22. By adopting this configuration, the resin composition 6 can function as an adhesive and improve the bonding strength between the joint portion of the second wire 32 and the second lead 22 and the encapsulating resin 5. Therefore, the semiconductor device A4 can suppress the peeling between the joint portion and the encapsulating resin 5. If such peeling occurs, when a thermal load is applied to the semiconductor device A4, for example, thermal stress is applied to the neck portion (the connection portion between the second joint portion 322 and the linear portion 323) of the second wire 32, which may break the wire at this neck portion. However, in the semiconductor device A4, since the peeling between the joint portion of the second wire 32 and the second lead 22 and the encapsulating resin 5 can be suppressed, the thermal stress applied to this neck portion can be alleviated. Therefore, the semiconductor device A4 can suppress malfunctions (such as wire breakage of the second wire 32) caused by the peeling of the encapsulating resin 5. In particular, in the semiconductor device A4, since the second wire 32 is a metal containing Al and the second lead 22 is a metal containing Cu, the thermal stress applied to this neck portion becomes large. Therefore, it is effective in suppressing malfunctions of the semiconductor device A4 to alleviate the thermal stress applied to this neck portion by the lead-side covering portion 63.

[0126] According to the semiconductor device A4, the second wire 32 is thinner than each first wire 31. Therefore, the second wire 32 is more likely to have a wire break due to corrosion than each first wire 31. However, in the semiconductor device A4, since the resin composition 6 includes a lead-side covering portion 63 and the lead-side covering portion 63 serves as a protective material, the corrosion of the second wire 32 (for example, the connection portion (neck portion) between the second joint portion 322 and the linear portion 323) can be suppressed. That is, the semiconductor device A4 can suppress wire breakage due to the corrosion of the second wire 32.

[0127] According to the semiconductor device A4, the resin composition 6 includes a lead-side covering portion 64, and the lead-side covering portion 64 covers the joint portion between the third wire 33 and the third lead 23. By adopting this configuration, the resin composition 6 functions as an adhesive, and the bonding strength between the joint portion between the third wire 33 and the third lead 23 and the encapsulating resin 5 can be improved. Therefore, the semiconductor device A4 can suppress the peeling between the joint portion and the encapsulating resin 5. If such peeling occurs, when a thermal load is applied to the semiconductor device A4, for example, thermal stress is applied to the neck portion (the connection portion between the second joint portion 332 and the linear portion 333) of the third wire 33, and there is a possibility of disconnecting this neck portion. However, in the semiconductor device A4, since the peeling between the joint portion between the third wire 33 and the third lead 23 and the encapsulating resin 5 can be suppressed, the thermal stress applied to this neck portion can be alleviated. Therefore, the semiconductor device A4 can suppress malfunctions (such as disconnection of the third wire 33) caused by the peeling of the encapsulating resin 5. In particular, in the semiconductor device A4, since the third wire 33 is a metal containing Al and the third lead 23 is a metal containing Cu, the thermal stress applied to this neck portion becomes large. Therefore, relaxing the thermal stress applied to this neck portion by the lead-side covering portion 64 is effective in suppressing malfunctions of the semiconductor device A4.

[0128] According to the semiconductor device A4, the third wire 33 is thinner than each first wire 31. Therefore, the third wire 33 is more likely to be disconnected due to corrosion than each first wire 31. However, in the semiconductor device A4, since the resin composition 6 includes a lead-side covering portion 64 and the lead-side covering portion 64 serves as a protective material, corrosion of the third wire 33 (for example, the connection portion (neck portion) between the second joint portion 332 and the linear portion 333) can be suppressed. That is, the semiconductor device A4 can suppress disconnection of the third wire 33 due to corrosion.

[0129] In the fourth embodiment, the case where the second wire 32 and the third wire 33 are each made of a metal containing Al is shown, but the present invention is not limited thereto. For example, the second wire 32 may be composed of a metal containing Cu or a metal containing Au. Even in this case, the lead-side coating portion 63 serves as an adhesive, and the bonding strength between the bonding portion of the second wire 32 and the second lead 22 and the encapsulating resin 5 can be improved. Similarly, for example, the third wire 33 may be composed of a metal containing Cu or a metal containing Au. Even in this case, the lead-side coating portion 64 serves as an adhesive, and the bonding strength between the bonding portion of the third wire 33 and the third lead 23 and the encapsulating resin 5 can be improved.

[0130] Figs. 29 to 31 show a semiconductor device according to the fifth embodiment. The semiconductor device A5 of the fifth embodiment has a different formation region of the resin composition 6 compared to the semiconductor device A4. Specifically, the resin composition 6 of the semiconductor device A5 further includes an element-side coating portion 65. Fig. 29 is a plan view showing the semiconductor device A5, corresponding to Fig. 25 in the fourth embodiment. Fig. 30 is a cross-sectional view taken along line XXX-XXX of Fig. 29. Fig. 31 is a cross-sectional view taken along line XXXI-XXXI of Fig. 29.

[0131] The element-side coating portion 65 covers the bonding portion between the second wire 32 and the second main surface electrode 112 and the bonding portion between the third wire 33 and the third main surface electrode 113, respectively. In a plan view, the element-side coating portion 65 spreads around from each of these bonding portions. In a plan view, the element-side coating portion 65 overlaps a part of the first main surface electrode 111 and covers a part of the first main surface electrode 111. However, the element-side coating portion 65 (resin composition 6) does not cover the portion (region R1 shown in Fig. 29) of the first main surface electrode 111 where each first wire 31 can be bonded. In the example shown in Fig. 29, the element-side coating portion 65 is connected to the die pad-side coating portion 61, but the element-side coating portion 65 may not be connected to the die pad-side coating portion 61.

[0132] According to the semiconductor device A5, similar to the semiconductor device A1, a resin composition 6 is provided. This resin composition 6 covers the joint portion (die pad side joint portion or lead side joint portion) between the conductive member (for example, the conductive bonding material 4 or the first wire 31) and the lead frame 2. Therefore, also in the semiconductor device A5, similar to the semiconductor device A1, it is possible to suppress malfunction caused by peeling of the encapsulation resin 5.

[0133] According to the semiconductor device A5, the resin composition 6 includes an element side covering portion 65. The element side covering portion 65 covers the joint portion between the second wire 32 and the second main surface electrode 112, and the joint portion between the third wire 33 and the third main surface electrode 113. By adopting this configuration, the resin composition 6 becomes an adhesive, and the bonding strength between the joint portion of the second wire 32 and the second lead 22 and the encapsulation resin 5, and the bonding strength between the joint portion of the third wire 33 and the third lead 23 and the encapsulation resin 5 can be improved. Therefore, the semiconductor device A5 can suppress the encapsulation resin 5 from peeling off from these joint portions, so that it is possible to suppress malfunction caused by peeling of the encapsulation resin 5. Note that a part of the element main surface 1a (mainly the second main surface electrode 112 and the third main surface electrode 113) is covered with the resin composition 6 by the element side covering portion 65, but during the operation of the semiconductor device A5, the second main surface electrode 112 and the third main surface electrode 113 generate less heat than the first main surface electrode 111. Therefore, the influence of the decrease in heat dissipation due to a part of the element main surface 1a being covered with the resin composition 6 is small.

[0134] In the fifth embodiment, the case where the element side covering portion 65 covers a part of the first main surface electrode 111 is shown, but it is not limited thereto. For example, the element side covering portion 65 may not cover the first main surface electrode 111. That is, all of the first main surface electrode 111 may be exposed from the resin composition 6.

[0135] In the fifth embodiment, the case where the resin composition 6 includes the die pad side covering portion 61, the plurality of lead side covering portions 62, 63, 64, and the element side covering portion 65 has been shown. However, the resin composition 6 does not necessarily include all of these. That is, the resin composition 6 may include at least one or more of these.

[0136] Note that, as for the lead side covering portion 63 shown in the fourth embodiment and the element side covering portion 65 shown in the fifth embodiment, one or both of them may be added to the semiconductor device A3.

[0137] In the first to fifth embodiments, the case where the semiconductor element 1 has a vertical structure including the main surface electrode 11 and the back surface electrode 12 has been shown, but it is not limited thereto. For example, the semiconductor element 1 may have a horizontal structure that does not include the back surface electrode 12 (including the main surface electrode 11). In this case, as the conductive bonding material 4, an Ag paste may be used instead of solder.

[0138] In the first to fifth embodiments, the case where the pad back surface 24b of the die pad 24 of the lead frame 2 is exposed from the sealing resin 5 has been shown, but it is not limited thereto, and the pad back surface 24b may be covered with the sealing resin 5.

[0139] In the first to fifth embodiments, the case where the semiconductor devices A1 to A5 are surface mount types has been shown, but they are not limited to surface mount types and may be lead insertion types. Also, in the first to fifth embodiments, the case where the lead frame 2 protrudes from the sealing resin 5 in a plan view has been shown, but it is not limited thereto. For example, a so-called non-lead package type in which the lead frame 2 does not protrude from the sealing resin 5 in a plan view may be used. Therefore, the package shape of the semiconductor device of the present disclosure is not particularly limited and can be applied to various package types.

[0140] The semiconductor device and its manufacturing method according to the present disclosure are not limited to the above-described embodiments. Specific configurations of each part of the semiconductor device of the present disclosure and specific processes of each step of the manufacturing method of the present disclosure can be freely designed in various ways.

Claims

1. a semiconductor element having a main surface and a rear surface spaced apart from each other in a first direction, and a side surface connected to the main surface and the rear surface; a lead frame on which the semiconductor element is mounted; a conductive member joined to the lead frame for electrically connecting the semiconductor element and the lead frame; a sealing resin that covers a portion of the lead frame and the semiconductor element, the lead frame includes a die pad and a lead spaced apart from the die pad; the semiconductor element is mounted on the die pad and has a first main surface electrode formed on a main surface of the element; the conductive member includes a first wire bonded to the first principal surface electrode and the lead to electrically connect the first principal surface electrode and the lead, a lead-side covering portion covering a joint portion between the first wire and the lead; Semiconductor device.

2. the die pad has a pad main surface facing in the same direction as the element main surface and a pad back surface facing in the same direction as the element back surface, The pad main surface faces the element rear surface. The semiconductor device according to claim 1 .

3. the semiconductor element includes a back electrode formed on a back surface of the element, the conductive member includes a conductive bonding material that bonds and conducts electricity between the semiconductor element and the die pad, The semiconductor device according to claim 2 , wherein the conductive bonding material bonds and conducts electricity between the back electrode and the die pad.

4. the conductive bonding material has an element contact surface that contacts the back electrode, a die pad contact surface that contacts the die pad, and a connecting surface that connects the element contact surface and the die pad contact surface, a die pad side covering portion for covering a bonding portion between the conductive bonding material and the die pad, the die pad side covering portion includes a die pad side first portion interposed between the connecting surface and the sealing resin. The semiconductor device according to claim 3 .

5. the die pad side covering portion further includes a die pad side second portion connected to the die pad side first portion and interposed between the pad main surface and the sealing resin; The semiconductor device according to claim 4.

6. the die pad side covering portion further includes a die pad side third portion connected to the die pad side first portion and interposed between at least a part of the element side surface and the sealing resin.

6. The semiconductor device according to claim 4 or 5.

7. 7. The semiconductor device according to claim 6, wherein the die pad covering portion further includes a die pad fourth portion interposed between at least a part of the element main surface and the sealing resin.

8. The conductive bonding material is solder.

8. The semiconductor device according to claim 3, wherein the first insulating layer is a first insulating layer.

9. The rear surface of the pad is exposed from the sealing resin.

9. The semiconductor device according to claim 3.

10. the first wire includes a first joint portion joined to the first principal surface electrode and a second joint portion joined to the lead; The semiconductor device according to claim 1 .

11. the first wire further includes a linear portion connecting the first joint portion and the second joint portion, The linear portion includes a resin abutment region that contacts the sealing resin over the entire circumferential direction. The semiconductor device according to claim 10.

12. The semiconductor device according to claim 1 , wherein the lead-side covering portion is offset to one side in the first direction with respect to the semiconductor element.

13. The semiconductor device according to claim 1 , wherein the lead-side covering portion is made of a resin composition.

14. The semiconductor device according to claim 3 , further comprising a die pad side covering portion that covers a joint portion between said conductive bonding material and said die pad.

15. The semiconductor device according to claim 14 , wherein the die pad side covering portion is made of a resin composition.

16. Further comprising an element side covering portion, the semiconductor element has a second principal surface electrode formed on the principal surface of the element; the conductive member includes a second wire bonded to the second principal surface electrode and the lead frame; The semiconductor device according to claim 1 , wherein the element side covering portion covers a joint portion between the second wire and the second principal surface electrode.

17. The semiconductor device according to claim 16 , wherein the element side cover is made of a resin composition.

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