JP2019004137A - Semiconductor device and manufacturing method of the same - Google Patents

Abstract

To provide a semiconductor device which uses a plurality of types of wires and which can inhibit variation in bond strengths of the wires; and provide a manufacturing method of the semiconductor device.SOLUTION: A semiconductor device includes semiconductor elements 11, 12, a bonding body (lead frame), a first wire 31, a wire piece 4 and a second wire 32. The bonded body is conducted to the semiconductor elements. The first wire is made of first metal. The first wire includes a first bonding part bonded to the bonding body and a first linear part 313 extending from the first bonding part. The wire piece is made of the first metal. The wire piece is bonded to the bonding body. The second wire is made of second metal different from the first metal. The second wire includes a second bonding part 321 bonded to the bonding body via the wire piece and a second linear part 323 extending from the second bonding part.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a semiconductor device using a wire and a manufacturing method thereof.

  Patent Document 1 discloses an example of a conventional semiconductor device. The semiconductor device disclosed in this document includes a lead frame, a semiconductor element, and a plurality of wires. The plurality of wires include two types of wires made of different materials. The bonding strength between the wire and the portion connecting the wire may differ depending on the combination of materials. For this reason, the bonding strength of the plurality of wires varies, and there is a problem that any one of the bonding strengths may be relatively weak. For example, in Patent Document 1 described above, a measure of changing the lead frame plating material in accordance with the wire material is adopted. In this case, there is a concern that the manufacturing efficiency of the lead frame is reduced and the cost is increased, and sufficient improvement has not been achieved.

JP 2003-209132 A

  An object of the present disclosure is to provide a more preferable semiconductor device and a manufacturing method thereof. For example, in the present disclosure, when using a plurality of types of wires, it is an object of the present disclosure to provide a semiconductor device and a manufacturing method thereof that can suppress variations in bonding strength of these wires.

  According to a first aspect of the present disclosure, a semiconductor device is provided. The semiconductor device includes a semiconductor element, an object to be joined, a first wire, a wire piece, and a second wire. The joined body is electrically connected to the semiconductor element. The material of the first wire is a first metal. The first wire includes a first bonding portion bonded to the member to be bonded and a first linear portion extending from the first bonding portion. The wire piece is made of the first metal. The wire piece is bonded to the object to be bonded. The material of the second wire is a second metal different from the first metal. The second wire includes a second bonding portion bonded to the member to be bonded via the wire piece and a second linear portion extending from the second bonding portion.

  According to a second aspect of the present disclosure, a method for manufacturing a semiconductor device is provided. The manufacturing method includes forming a wire piece by bonding a part of a first wiring material made of a first metal to a bonded body, and using the first wiring material to form the bonded body. Forming a first wire including a bonded first bonding portion and a first linear portion extending from the first bonding portion; and a second wiring member made of a second metal different from the first metal. And forming a second wire including a second bonding portion bonded to the wire piece and a second linear portion extending from the second bonding portion.

It is a perspective view showing a semiconductor device concerning an embodiment of this indication. It is a top view showing a semiconductor device concerning an embodiment of this indication. It is a side view showing a semiconductor device concerning an embodiment of this indication. It is a partial expanded sectional view of a semiconductor device concerning an embodiment of this indication. It is a figure showing one process of a manufacturing method concerning an embodiment of this indication. It is a figure showing one process of a manufacturing method concerning an embodiment of this indication. It is a figure which shows an example of the wedge tool used by embodiment of this indication. It is a figure which shows a mode that a wire piece is formed. It is sectional drawing of the 1st wiring material and wire piece in the wire piece formation process shown to FIG. 8A-C. It is a figure showing one process of a manufacturing method concerning an embodiment of this indication. It is a figure which shows a mode that a 2nd wire is formed in the 2nd wire formation process which concerns on embodiment of this indication. It is a figure showing one process of a manufacturing method concerning an embodiment of this indication. It is various sectional views showing a wire bonding structure of a semiconductor device concerning an embodiment of this indication. It is a top view showing a wire bonding structure of a semiconductor device concerning an embodiment of this indication. It is a top view showing a semiconductor device concerning a modification of this indication. It is various sectional drawings which show the wire bonding structure of the semiconductor device which concerns on the modification of this indication. It is a top view which shows the wire bonding structure of the semiconductor device which concerns on the modification of this indication. The wedge tool which concerns on a modification is shown. It is a figure which shows the wire piece formed with the wedge tool. It is a perspective view showing a semiconductor device concerning an embodiment of this indication. It is a top view showing a semiconductor device concerning an embodiment of this indication. It is a side view showing a semiconductor device concerning an embodiment of this indication. It is a partial expanded sectional view of a semiconductor device concerning an embodiment of this indication. It is a figure for demonstrating the laminated structure of an anodized film. It is a figure showing one process of a manufacturing method of a semiconductor device concerning an embodiment of this indication. It is a figure showing one process of a manufacturing method of a semiconductor device concerning an embodiment of this indication. It is a figure which shows 1 process (anodic oxidation process process) of the manufacturing method of the semiconductor device which concerns on embodiment of this indication. It is a figure showing one process of a manufacturing method of a semiconductor device concerning an embodiment of this indication. It is a figure which shows the sealing process which concerns on the modification of this indication.

  Hereinafter, embodiments of the present disclosure will be specifically described with reference to the drawings.

  1 to 4 illustrate a semiconductor device A1 according to an embodiment of the present disclosure. The semiconductor device A1 of the present disclosure is mounted on an electrical circuit board such as an automobile or an electronic device. The semiconductor device A1 includes a plurality of semiconductor chips 1, a lead frame 2, a plurality of wires 3, a wire piece 4, and a resin package 5. FIG. 1 is a perspective view of the semiconductor device A1. FIG. 2 is a plan view of the semiconductor device A1. FIG. 3 is a side view of the semiconductor device A1, and shows the side surface when viewed from the left side in FIG. FIG. 4 is a partially enlarged cross-sectional view of the semiconductor device A1. 1 to 3, the resin package 5 is indicated by an imaginary line. In FIG. 4, the resin package 5 is not shown. In the following, for convenience of understanding, an orthogonal coordinate system defined by the x, y, and z directions orthogonal to each other will be defined and described. The z direction is the thickness direction of the semiconductor device A1.

  Each of the plurality of semiconductor chips 1 is a circuit element made of a semiconductor material, and is an electronic component that is the center of the function of the semiconductor device A1. In the present embodiment, the semiconductor device A1 includes a plurality of first semiconductor chips 11 and second semiconductor chips 12 as the plurality of semiconductor chips 1.

  Each of the plurality of first semiconductor chips 11 has a rectangular shape in plan view. Each first semiconductor chip 11 is a power chip such as an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a diode. Each first semiconductor chip 11 is not limited to the above. In the present embodiment, the semiconductor device A1 includes two first semiconductor chips 11. Each first semiconductor chip 11 has a chip main surface 111 and a chip back surface 112. The chip main surface 111 is a surface facing the z1 direction. The chip back surface 112 is a surface facing the z2 direction. Each first semiconductor chip 11 has an electrode pad 113.

  Each electrode pad 113 is made of pure aluminum. Each electrode pad 113 may be an aluminum alloy. Each electrode pad 113 has a pad main surface 113a, a pad back surface 113b, and a pad side surface 113c. The pad main surface 113a is a surface facing the z1 direction. In the present embodiment, the pad main surface 113a has a rectangular shape in plan view. The pad back surface 113b is a surface facing the z2 direction. The pad side surface 113c has a surface facing the x1 direction, a surface facing the x2 direction, a surface facing the y1 direction, and a surface facing the y2 direction. In each first semiconductor chip 11, the pad main surface 113 a forms part of the chip main surface 111. That is, the pad main surface 113a is at the same position as the chip main surface 111 in the z direction. The pad main surface 113a and the chip main surface 111 may be at different positions in the z direction. A wire 3 (first wire 31 described later) is bonded to the pad main surface 113a.

  The second semiconductor chip 12 has a rectangular shape in plan view. The second semiconductor chip 12 is an LSI chip such as a control IC, for example. The second semiconductor chip 12 is not limited to the above. In the present embodiment, the semiconductor device A1 has one second semiconductor chip 12. The second semiconductor chip 12 has a chip main surface 121 and a chip back surface 122. The chip main surface 121 is a surface facing the z1 direction. The chip back surface 122 is a surface facing the z2 direction. A plurality of wires 3 (second wire 32 described later and third wire 33 described later) are bonded to the chip main surface 121. In detail, the chip main surface 121 has an electrode pad, and the plurality of wires 3 are bonded to the electrode pad. Examples of the material of the surface layer of the electrode pad include, but are not limited to, aluminum, nickel / palladium, nickel / palladium gold, and the like.

  The lead frame 2 is made of a conductive material. An example of such a conductive material is Cu. The lead frame 2 is joined to the electrical circuit board to form a conduction path between the plurality of semiconductor chips 1 and the electrical circuit board. The lead frame 2 is Ni-plated on all surfaces. The lead frame 2 corresponds to an example of a “bonded body”. The lead frame 2 includes a plurality of die bonding parts 21, a plurality of wire bonding parts 22, a plurality of terminal parts 23, and a plurality of heat dissipation parts 24 as functional components.

  Each of the plurality of die bonding portions 21 is a portion that supports the semiconductor chip 1. Each die bonding portion 21 has a plate shape along the xy plane. In the present embodiment, the plurality of die bonding portions 21 include a plurality of first die bonding portions 211 and second die bonding portions 212.

  The first semiconductor chip 11 is bonded to each of the plurality of first die bonding portions 211. Each first die bonding portion 211 is formed larger than the outer shape of the first semiconductor chip 11 when viewed in the z direction. In the present embodiment, the lead frame 2 has two first die bonding portions 211. The second die bonding part 212 is joined to the second semiconductor chip 12. The second die bonding part 212 is formed larger than the outer shape of the second semiconductor chip 12 when viewed in the z direction. In the present embodiment, the lead frame 2 has one second die bonding part 212. The second die bonding portions 212 are located in the z1 direction from the first die bonding portions 211.

  In the present embodiment, a bonding layer 91 is interposed between each first die bonding portion 211 and each first semiconductor chip 11 supported by the first die bonding portion 211. The bonding layer 91 is made of a conductive material. Such a conductive material is, for example, solder or silver paste. Solder has a relatively high thermal conductivity. When solder is used as the bonding layer 91, heat can be efficiently transferred from the first semiconductor chip 11 to the first die bonding portion 211. Although a predetermined bonding layer is interposed between the second die bonding part 212 and the second semiconductor chip 12 supported by the second die bonding part 212, the illustration is omitted.

  Each of the plurality of wire bonding portions 22 is a portion that supports the wire 3. In the present embodiment, the plurality of wire bonding units 22 includes a plurality of first wire bonding units 221 and a plurality of second wire bonding units 222.

  A first wire 31 (described later) is joined to each of the plurality of first wire bonding portions 221. In the present embodiment, the lead frame 2 has two first wire bonding portions 221. The wire piece 4 is bonded to each of the plurality of second wire bonding portions 222. Each second wire bonding portion 222 is electrically connected to a second wire 32 (described later) through the bonded wire pieces 4. In the present embodiment, since the entire lead frame 2 is plated as described above, each first wire bonding portion 221 and each second wire bonding portion 222 have a plating surface facing the z1 direction. ing. In the present embodiment, the lead frame 2 has seven second wire bonding portions 222. The first wire bonding part 221 corresponds to an example of a “first bonding part”. Further, the second wire bonding part 222 corresponds to an example of “second bonding part”.

  The plurality of terminal portions 23 are terminals that are electrically connected to the electrical circuit board. That is, the plurality of terminal portions 23 function as connector pins of the semiconductor device A1. Each of the plurality of terminal portions 23 is exposed from the resin package 5. The plurality of terminal portions 23 are arranged in the y direction. Further, the plurality of terminal portions 23 are located in the x2 direction from the resin package 5. Each terminal portion 23 is bent. In the present embodiment, the lead frame 2 has nine terminal portions 23.

  Each of the plurality of heat radiating portions 24 is a portion that releases heat generated in the semiconductor chip 1 to the outside. Each heat dissipating part 24 is exposed from the resin package 5. In the present embodiment, each heat radiating part 24 is connected to each first die bonding part 211. The plurality of heat dissipating parts 24 are arranged in the y direction and are located in the x1 direction from the resin package 5 in a plan view. In the present embodiment, since the first semiconductor chip 11 is a power chip, it generates a large amount of heat. Therefore, the plurality of heat radiating portions 24 are provided mainly for releasing heat generated in the first semiconductor chip 11. In the present embodiment, the lead frame 2 has two heat radiating portions 24. The plurality of heat radiating portions 24 may be a part of the lead frame 2 or may be formed by joining members different from the lead frame 2.

  The lead frame 2 includes a plurality of leads. In the present embodiment, the semiconductor device A1 has nine leads (first to ninth leads 2A to 2I) spaced apart from each other as the lead frame 2.

  The first lead 2 </ b> A has a terminal part 23, a first die bonding part 211, and a heat radiating part 24. In the first lead 2A, these are connected and formed integrally. As shown in FIGS. 1 and 3, the first lead 2 </ b> A is bent at a portion connecting the terminal portion 23 and the first die bonding portion 211. The first lead 2 </ b> A supports the first semiconductor chip 11.

  The second lead 2B has a terminal portion 23 and a second wire bonding portion 222. In the second lead 2B, these are connected and formed integrally. A second wire 32 is joined to the second lead 2 </ b> B via a wire piece 4. The third lead 2C, the fifth lead 2E, the sixth lead 2F, and the seventh lead 2G are the same as the second lead 2B.

  The fourth lead 2D has a terminal portion 23, a second wire bonding portion 222, and a second die bonding portion 212. In the fourth lead 2D, these are connected and formed integrally. The fourth lead 2D supports the second semiconductor chip 12. A second wire 32 is joined to the fourth lead 2D via a wire piece 4.

  The eighth lead 2 </ b> H has a terminal portion 23, a first wire bonding portion 221, and a second wire bonding portion 222. In the eighth lead 2H, these are connected and formed integrally. The first wire 31 is joined to the eighth lead 2H, and the second wire 32 is joined via the wire piece 4.

  The ninth lead 2 </ b> I includes a terminal portion 23, a first die bonding portion 211, a first wire bonding portion 221, and a heat dissipation portion 24. In the ninth lead 2I, these are connected and formed integrally. As shown in FIGS. 1 and 3, the ninth lead 2 </ b> I is bent at a portion connecting the terminal portion 23 and the first die bonding portion 211. The ninth lead 2I supports the first semiconductor chip 11. The first wire 31 is joined to the ninth lead 2I.

  Each of the plurality of wires 3 connects the first semiconductor chip 11 and the second semiconductor chip 12 to the lead frame 2. In the present embodiment, the plurality of wires 3 include a plurality of first wires 31, a plurality of second wires 32, and a plurality of third wires 33.

  Each of the plurality of first wires 31 is mainly composed of a first metal. Each of the plurality of second wires 32 and each of the plurality of third wires 33 is mainly composed of a second metal. The first metal has a relatively good bonding strength in metal bonding with the lead frame 2 as the bonded body. The second metal has a relatively inferior bonding strength in the metal bonding with the lead frame 2 as an object to be bonded, and has a good bonding strength in the metal bonding with the first metal. In the present embodiment, since the lead frame 2 is Ni-plated, the first metal and the second metal may be selected based on the compatibility of metal bonding with Ni. As such a first metal, there is a metal whose main component is aluminum, and as a second metal, there is a metal whose main component is gold or copper. In the present embodiment, each first wire 31 is an aluminum alloy to which any one of iron, silicon, and nickel is added. Each first wire 31 may be pure aluminum. Each second wire 32 and each third wire 33 are gold.

  Each first wire 31 has one end bonded to the first semiconductor chip 11 and the other end bonded to the lead frame 2. In addition, each 1st wire 31 is formed using the wedge tool 6 mentioned later. In the present embodiment, the semiconductor device A <b> 1 has two first wires 31. Each first wire 31 includes a pair of wedge joint portions 311 and 312 and a first linear portion 313.

  The pair of wedge joint portions 311 and 312 are both portions formed by wedge bonding using the wedge tool 6. The wedge bonding part 311 is bonded to the first semiconductor chip 11 (electrode pad 113). The wedge bonding portion 312 is bonded to the lead frame 2 (first wire bonding portion 221). The first linear portion 313 is a portion that connects the wedge joint portion 311 and the wedge joint portion 312. The first linear portion 313 extends from the pair of wedge joint portions 311 and 312, respectively. The first linear portion 313 has a circular cross-sectional shape perpendicular to the major axis direction, and a diameter of 300 to 400 μm. That is, the wire diameter of each first wire 31 is 300 to 400 μm. In addition, the wire diameter of each 1st wire 31 is not limited to this. In the present embodiment, the wedge bonding portion 312 corresponds to an example of a “first bonding portion”.

  Each of the plurality of second wires 32 has one end bonded to the lead frame 2 (second wire bonding portion 222) via the wire piece 4, and the other end connected to the second semiconductor chip 12 (chip main surface 121). It is joined. Each second wire 32 is formed using a capillary 7 described later. In the present embodiment, the semiconductor device A1 has eight second wires 32. Each second wire 32 includes a ball joint portion 321, a stitch joint portion 322, and a second linear portion 323.

  The ball bonding portion 321 is a portion formed by ball bonding using the capillary 7. The ball joint portion 321 is joined to the wire piece 4. The stitch joint portion 322 is a portion formed by stitch bonding using the capillary 7. The stitch joint portion 322 is joined to the second semiconductor chip 12 (chip main surface 121). The second linear portion 323 is a portion that connects the ball joint portion 321 and the stitch joint portion 322. The second linear portions 323 extend from the ball joint portion 321 and the stitch joint portion 322, respectively. In the present embodiment, the second linear portion 323 is formed in a linear shape. The second linear portion 323 has a circular cross-sectional shape perpendicular to the long axis direction and a diameter of 40 to 100 μm. That is, the wire diameter of each second wire 32 is 40 to 100 μm. In addition, the wire diameter of each 2nd wire 32 is not limited to this. In the present embodiment, the ball bonding portion 321 corresponds to an example of a “second bonding portion”.

  Each of the plurality of third wires 33 has one end bonded to the first semiconductor chip 11 (chip main surface 111) and the other end bonded to the second semiconductor chip 12 (chip main surface 121). Each third wire 33 is formed using a capillary 7 described later. In the present embodiment, the semiconductor device A <b> 1 has three third wires 33. Each third wire 33 includes a ball joint portion 331, a stitch joint portion 332, and a third linear portion 333.

  The ball bonding portion 331 is a portion formed by ball bonding using the capillary 7. The ball bonding portion 331 is bonded to the first semiconductor chip 11 (chip main surface 111). The stitch joint portion 332 is a portion formed by stitch bonding using the capillary 7. The stitch joint portion 332 is joined to the second semiconductor chip 12 (chip main surface 121). The third linear portion 333 is a portion that connects the ball joint portion 331 and the stitch joint portion 332. The third linear portion 333 extends from the ball joint portion 331 and the stitch joint portion 332, respectively. In the present embodiment, the third linear portion 333 is formed in a linear shape. The third linear portion 333 has a circular cross-sectional shape perpendicular to the long axis direction and a diameter of 40 to 100 μm. That is, the wire diameter of each third wire 33 is 40 to 100 μm. In addition, the wire diameter of each 3rd wire 33 is not limited to this.

  Each of the plurality of wire pieces 4 is made of the same material as the plurality of first wires 31. That is, the plurality of wire pieces 4 are mainly composed of the first metal. In this embodiment, each wire piece 4 is an aluminum alloy to which any of iron, silicon, and nickel is added. In addition, when each 1st wire 31 is a pure aluminum, each wire piece 4 is also a pure aluminum. Each wire piece 4 has an elongated shape, and has a rectangular shape in plan view. Each wire piece 4 is joined to the second wire bonding part 222. Moreover, the 2nd wire 32 is joined to each of the some wire piece 4 from the z1 direction. Each wire piece 4 is formed using a wedge tool 6 described later. Each wire piece 4 has substantially the same size as the wedge joint 311 of the first wire 31.

  The resin package 5 covers the plurality of semiconductor chips 1, a part of the lead frame 2, the plurality of wires 3, and the plurality of wire pieces 4. The resin package 5 is a thermosetting synthetic resin having electrical insulation. In this embodiment, it is a black epoxy resin. Further, the resin package 5 has a rectangular shape in plan view.

  Next, a method for manufacturing the semiconductor device A1 according to the embodiment of the present disclosure will be described. The manufacturing method according to the present embodiment includes a lead frame pre-process, a die bonding process, a wire bonding process, a resin molding process, and a lead frame post-process. The semiconductor device A1 is manufactured through the plurality of steps. In the present embodiment, the steps described above are performed in the order described above.

  In the lead frame pre-process, preparation for forming the lead frame 2 having the above-described configuration is performed. Specifically, in the lead frame pre-process, a copper metal plate is prepared, and the copper metal plate is punched. The punching process may be performed using a known method. Thereby, the lead frame 200 shown in FIG. 5 is obtained. The lead frame 200 includes a frame 201 and a plurality of leads (first to ninth leads 2A to 2I) supported by the frame 201. The first to ninth leads 2A to 2I are formed with portions corresponding to the die bonding portion 21, the wire bonding portion 22, the terminal portion 23, and the heat dissipation portion 24 described above. At this stage, the lead frame 200 has a plate shape and is not bent.

  Next, the lead frame 200 is bent. In the bending process, the lead frame 200 is bent so that the plurality of first die bonding portions 211 are translated in the z2 direction. Accordingly, the plurality of first die bonding portions 211 are positioned in the z2 direction with respect to the second die bonding portion 212. In the lead frame pre-process, the punching process and the bending process may be performed simultaneously.

  Thereafter, a plating process is performed. In the present embodiment, the entire lead frame 2 is plated with Ni. Note that only the first wire bonding portions 221 and the second wire bonding portions 222 may be plated.

  Subsequently, in the die bonding process, a plurality of semiconductor chips 1 are die bonded to the die bonding portion 21 of the lead frame 200. In the present embodiment, each first semiconductor chip 11 is disposed on each first die bonding portion 211 via a bonding layer 91. Thereby, each first semiconductor chip 11 is bonded to each first die bonding portion 211. Further, the second semiconductor chip 12 is disposed on the second die bonding portion 212 via a bonding layer (not shown). As a result, the second semiconductor chip 12 is bonded to the second die bonding part 212. In the die bonding step, the technique is not limited as long as a plurality of semiconductor chips 1 can be die bonded at predetermined positions. By performing the die bonding process, the lead frame 200 shown in FIG. 6 is obtained.

  Subsequently, in the wire bonding step, the plurality of wires 3 and the wire pieces 4 are bonded to the lead frame 200 and the plurality of semiconductor chips 1 bonded to the lead frame 200. In the present embodiment, the wire bonding step includes a wire piece forming step, a first wire forming step, a second wire forming step, and a third wire forming step, which are performed in this order. Note that the order of the wire piece forming step and the first wire forming step may be reversed. Further, the order of the second wire forming step and the third wire forming step may be reversed.

  First, in the wire piece forming step, a plurality of wire pieces 4 are formed from the first wiring member 301 using a wedge bonding apparatus. The first wiring member 301 is a metal whose main component is conductive. In the present embodiment, the first wiring member 301 is an aluminum alloy in which the main component is aluminum and any one of iron, silicon, and nickel is added to the aluminum. Moreover, the wire diameter of the 1st wiring material 301 is about 300-400 micrometers. 7A to 7C show an example of the wedge tool 6 of the wedge bonding apparatus used in this embodiment. The wedge tool 6 includes a wedge 61, a wire guide 62, and a cutter 63. In addition, a horn for supporting these components and applying ultrasonic vibration, a main body for supporting the horn, a wire reel for winding the first wiring member 301, and the like are provided, but illustration and description thereof are omitted. FIG. 7A is a front view showing the entire wedge tool 6. FIG. 7B is a perspective view showing the wedge 61. FIG. 7C is a cross-sectional view taken along line VII-VII shown in FIG. 7B.

  The wedge 61 presses the first wiring member 301 and joins the first wiring member 301 to the joining target by ultrasonic vibration. The wedge 61 is made of, for example, tungsten carbide. As shown in FIGS. 7A to 7C, a guide groove 611 is formed in the wedge 61. The guide groove 611 is provided at the lower end of the wedge 61. In the present embodiment, as shown in FIG. 7C, the cross-sectional shape of the guide groove 611 is V-shaped. The wire guide 62 is fixed to the wedge 61, and guides the first wiring member 301 wound around the wire reel to the wedge 61. The cutter 63 is for cutting the first wiring member 301. The cutter 63 is disposed adjacent to the wedge 61. The wire guide 62 and the cutter 63 are disposed on the opposite sides with the wedge 61 in between.

  8A-C and FIGS. 9A-B show how the wire piece 4 is formed using the wedge tool 6 configured as described above. 8A to 8C are front views of the wedge tool 6. 9A and 9B are cross-sectional views as viewed from the direction in which the first wiring member 301 extends (the longitudinal direction of the wire piece 4) at the tip of the wedge 61. FIG. FIG. 9A is a cross-sectional view of the first wiring member 301 at the time shown in FIG. 8A. FIG. 9B is a cross-sectional view of the wire piece 4 at the time shown in FIG. 8C.

  First, as shown in FIG. 7A, the tip of the wedge 61 of the wedge tool 6 that is in a state in which wedge bonding is possible in advance is positioned immediately above the second wire bonding portion 222. Then, the tip of the wedge 61 is directed toward the second wire bonding part 222. At this time, the tip portion of the first wiring member 301 is fitted in the guide groove 611.

  Next, as shown in FIG. 8A, wedge bonding is performed using the wedge tool 6. Specifically, ultrasonic vibration is applied while pressing the wedge 61 against the second wire bonding portion 222. At this time, as shown in FIG. 9A, the contact surface 412 is formed by pressing the first wiring member 301 against the second wire bonding portion 222. The contact surface 412 is a surface with a cross section retracted from the outer peripheral surface 413 on the circular arc toward the central axis Ox side of the first wiring member 301. In the present embodiment, since the surface of the second wire bonding part 222 is flat, the contact surface 412 is flat. In addition, two pressed surfaces 411 are formed when the first wiring member 301 is pressed against the second wire bonding part 222. Each pressed surface 411 is a portion pressed against the inner surface 611 a of the guide groove 611. Each pressed surface 411 is a surface that is retracted from the outer peripheral surface 413 having an arcuate cross section to the central axis Ox side of the first wiring member 301. Each of the pressed surfaces 411 appears as pressing marks 43 by the wedge tool 6 on the appearance. Then, the tip portion of the first wiring member 301 is further crushed by the ultrasonic vibration. Thereby, the front-end | tip part of the 1st wiring material 301 and the 2nd wire bonding part 222 are ultrasonic-welded.

  Next, the wedge tool 6 is moved to the left in the figure (see the black arrow in FIG. 8A). Due to this movement, as shown in FIG. 8B, the cutter 63 is positioned between the left end of the contact surface 412 in the drawing and the left end of the second wire bonding portion 222 in the drawing. Next, as shown in FIG. 8B, the cutter 63 is lowered (see the black arrow in FIG. 8B), and the first wiring member 301 is cut by the lowering of the cutter 63. The descending amount of the cutter 63 is set to such an extent that the cutter 63 does not completely cut the first wiring member 301. Thereafter, as shown in FIG. 8C, the first wiring member 301 is separated from the second wire bonding portion 222 together with the wedge 61. Thereby, the cut | disconnected 1st wiring material 301 is cut | disconnected and the wire piece 4 is formed. As shown in FIG. 9B, the wire piece 4 formed in this manner has an irregular shape having the pressed surface 411, the contact surface 412, and the outer peripheral surface 413 in its cross-sectional shape. Furthermore, as for the wire piece 4, the part most located in z1 direction in a cross-sectional shape continues in a longitudinal direction. That is, the wire piece 4 has a shape in which the ridges are continuous in the longitudinal direction. In addition, the pressed surface 411 of the wire piece 4 appears as the pressing mark 43 (wedge pressing mark) in appearance. And the torn surface 42 is formed in one edge of the longitudinal direction of the wire piece 4 by cut | disconnecting the 1st wiring material 301. FIG. A wire piece formation process is performed through such a process. Since the wire piece 4 is formed of the first wiring member 301, the wire diameter (cross-sectional dimension) of the wire piece 4 is slightly crushed by the wedge 61, but the wire diameter of the first wiring member 301 ( 300 to 400 μm).

  Subsequently, in the first wire forming step, the plurality of first wires 31 are formed using the wedge bonding apparatus. That is, the first wire forming process uses the same wedge tool 6 as the wire piece forming process.

  In the first wire forming step, the first wiring material 301 is firstly bonded to the first semiconductor chip 11 (electrode pad 113) using the wedge tool 6 in the same manner as the wedge bonding (see FIG. 8A) in the wire piece forming step. Wedge bonding. Specifically, ultrasonic vibration is applied while pressing the wedge 61 with the first wiring member 301 fitted in the guide groove 611 against the first semiconductor chip 11 (electrode pad 113). Thereby, the front-end | tip part of the 1st wiring material 301 and the electrode pad 113 are ultrasonically welded. This welded portion becomes the wedge joint 311 of the first wire 31.

  Next, unlike the wire piece forming step, the wedge tool 6 is moved (looping) while pulling out the first wiring member 301 without cutting the first wiring member 301. Thereby, the first linear portion 313 of the first wire 31 is formed. By this looping, the wedge 61 is positioned immediately above the first wire bonding portion 221.

  Next, the first wiring member 301 is wedge bonded to the first wire bonding portion 221 using the wedge tool 6. Specifically, the tip of the wedge 61 is directed toward the first wire bonding portion 221, and ultrasonic vibration is applied while pressing the wedge 61 against the first wire bonding portion 221. Thereby, the 1st wiring material 301 and the 1st wire bonding part 221 are ultrasonic-welded. This welded portion becomes the wedge joint portion 312 of the first wire 31. The shape of the wedge joint 312 is substantially the same as the shape of the wedge joint 311. After that, as in the wire piece forming step, as shown in FIGS. 8B and 8C, the first wiring member 301 is cut to form the first wire 31.

  Through such a process, the first wire forming process is performed. In the first wire forming step, the first wiring member 301 may be first wedge-bonded to the first wire bonding portion 221, looped, and then wedge-bonded to the electrode pad 113.

  The wire piece forming step is performed a plurality of times (the same number as the required number of wire pieces 4), and then the first wire forming step is performed a plurality of times (the same number as the required number of first wires 31). 10 is obtained.

  Subsequently, in the second wire forming step, a plurality of second wires 32 are formed from the second wiring member 302 using a ball bonding apparatus. The second wiring member 302 is a metal whose main component is conductive, and is a metal different from the first wiring member 301. In the present embodiment, the second wiring material 302 is mainly composed of gold. Moreover, the wire diameter of the 2nd wiring material 302 is about 40-100 micrometers. The ball bonding apparatus has a capillary 7.

  FIG. 11 shows how the second wire 32 is formed using the capillary 7.

  First, the second wiring member 302 is ball bonded to the wire piece 4 using the capillary 7. Specifically, the second wiring member 302 is protruded from the tip end of the capillary 7 and the protruding tip portion of the second wiring member 302 is dissolved. Thereby, the molten ball 71 is formed. Thereafter, the molten ball 71 is pressed against the wire piece 4. Then, ultrasonic vibration is applied while the molten ball 71 is pressed against the wire piece 4, and the ball-shaped second wiring member 302 is joined to the wire piece 4. Thereby, the ball joint portion 321 of the second wire 32 is formed. In addition, in the said ball bonding, when applying ultrasonic vibration, it is good to vibrate in the longitudinal direction of the wire piece 4. With this ultrasonic vibration, as shown in FIG. 4, the wire piece 4 protrudes in the z1 direction at both ends of the portion where the second wire 32 (ball bonding portion 321) is bonded in the direction in which the vibration is applied.

  Next, the capillary 7 is moved (looping) while pulling out the second wiring member 302 from the capillary 7. Thereby, the second linear portion 323 of the second wire 32 is formed. With this looping, the capillary 7 is positioned immediately above the bonding position of the chip main surface 121 of the second semiconductor chip 12. In the present embodiment, the wire piece 4 is linearly moved from the second semiconductor chip 12.

  Next, the second wiring member 302 is stitch bonded to the second semiconductor chip 12 using the capillary 7. Specifically, the ultrasonic vibration is applied while the capillary 7 is directed toward the chip main surface 121 and the second wiring member 302 is pressed against the chip main surface 121. As a result, the second wiring member 302 is bonded to the chip main surface 121, and the stitch bonding portion 322 of the second wire 32 is formed. Then, the capillary 7 is raised while holding the second wiring member 302. Thereby, the 2nd wiring material 302 is cut | disconnected and the 2nd wire 32 is formed. When the second wiring member 302 (second wire 32) is stitch bonded to the second semiconductor chip 12, the second semiconductor chip 12 is damaged by a pressing force or ultrasonic vibration during the stitch bonding. there is a possibility. In order to suppress such damage, for example, the second wire 32 may be bonded after forming bumps on the second semiconductor chip 12 using the second wiring member 302.

  Subsequently, in the third wire forming step, a plurality of third wires 33 are formed from the second wiring member 302 using a ball bonding apparatus, as in the second wire forming step. That is, the third wire 33 is also formed using the capillary 7. In the case of the third wire 33, the second wiring member 302 is ball bonded to the first semiconductor chip 11 (chip main surface 111). Thereby, the ball joint portion 331 is formed. Thereafter, looping is performed to form the third linear portion 333. In the present embodiment, the first semiconductor chip 11 is linearly moved from the second semiconductor chip 12. Then, the second wiring material 302 is stitch bonded to the second semiconductor chip 12 (chip main surface 121). As a result, the stitch joint 332 is formed. Then, the capillary 7 is raised while holding the second wiring member 302. Thereby, the 2nd wiring material 302 is cut | disconnected and the 3rd wire 33 is formed.

  A 2nd wire formation process and a 3rd wire formation process are performed through the above processes. Then, the second wire forming step is performed a plurality of times (the same number as the number of necessary second wires 32), and the third wire forming step is performed a plurality of times (the same number as the number of necessary third wires 33). Thus, the lead frame 200 shown in FIG. 12 is obtained. That is, FIG. 12 shows the state of the lead frame 200 after the wire bonding process.

  13A-C and FIG. 14 are formed by the second wire bonding portion 222, the wire piece 4, and the second wire 32 through the wire piece forming step and the second wire forming step. Is done. 13A to 13C are various cross-sectional views taken along a plane perpendicular to the longitudinal direction of the wire piece 4. FIG. 14 is a view (plan view) of the wire piece 4 after the second wire forming step as seen from the z1 direction. In FIG. 14, the wire piece 4 has a cross section shown in FIG. 13A described later.

  The wire bonding structure shown in FIGS. 13A to 13C depends on various conditions such as the pressing force and the environmental temperature during ball bonding of the second wire 32, and the relative hardness between the second wire 32 and the wire piece 4. It becomes one of the cross-sectional shapes shown in 13C. For convenience of understanding, in FIGS. 13A to 13C, the wire piece 4 (see FIG. 9B) before the second wire 32 is joined is indicated by a dotted line.

  FIGS. 13A and 14 show a wire bonding structure when the wire piece 4 is crushed by the second wire 32. In this case, as shown in FIG. 13A, the wire piece 4 has a recessed upper surface compared to the wire piece 4 before the second wire 32 is formed, and is one of the second wire 32 (ball joint portion 321). It is shaped to wrap the part. Moreover, the both ends of the said recessed part protrude. Further, the degree of curvature (curvature) of the lower surface of the ball bonding portion 321 is moderated by the wire piece 4 as compared with the case of the molten ball 71. Further, as shown in FIG. 14, the wire piece 4 is deformed by a part of the pressed surface 411 being crushed by the ball joint portion 321. FIG. 4 shows the case of the wire bonding structure shown in FIG. 13A. FIG. 13B shows a wire bonding structure when the second wire 32 and the wire piece 4 are crushed together. In this case, as shown in FIG. 13B, the lower surface of the second wire 32 (ball bonding portion 321) and the upper surface of the wire piece 4 are crushed substantially equally, and the lower surface of the ball bonding portion 321 and the upper surface of the wire piece 4 are flat. It has become. FIG. 13C shows a wire bonding structure when the wire piece 4 is not deformed. In this case, as shown in FIG. 13C, the lower surface of the second wire 32 (ball bonding portion 321) is curved along the shape of the upper surface of the wire piece 4. Further, in each of FIGS. 13A to 13C, the second wire 32 is formed on the wire piece 4, and the second wire 32 is separated from the second wire bonding portion 222. Note that the wire bonding structure shown in FIGS. 13A to 13C is not limited to that shown in FIG.

  In the resin molding process, the resin package 5 is formed. In the present embodiment, it is formed by molding. In the resin molding process, the lead frame 200 (see FIG. 12) after the wire bonding process is pressed by a mold (not shown), and a resin material is injected into the cavity of the mold. Then, the resin material is cured to form the resin package 5.

  In the lead frame post-process, a process for making the lead frame 200 after the resin molding process into the semiconductor device A1 shown in FIGS. 1 to 3 is performed. For this reason, in the lead frame post-process, cutting (cut-out) and bending are performed. In the cutting process, a portion where the first to ninth leads 2A to 2I and the frame 201 are connected is removed by cutting along a cutting line CL (dotted line) shown in FIG. Then, in the bending process, the portion of the first to ninth leads 2A to 2I protruding from the resin package 5 (terminal portion 23) is bent so that the tip portion in the x2 direction is translated in the z2 direction. Thereby, the some terminal part 23 makes the shape bent.

  The semiconductor device A1 shown in FIGS. 1 to 4 can be manufactured by sequentially performing the steps shown above.

  The lead frame 2 of the present embodiment is entirely plated with Ni. Therefore, when the second wire 32 whose main component is gold and the second wire bonding part 222 plated with Ni are directly bonded, the bonding strength tends to decrease. According to the present embodiment, the second wire 32 (ball bonding portion 321) is bonded to the second wire bonding portion 222 via the wire piece 4. The wire piece 4 is mainly composed of the same aluminum as the first wire 31. For this reason, the bonding strength between the second wire 32 and the wire piece 4 is stronger than the bonding strength when the second wire 32 is directly bonded to the second wire bonding portion 222. Therefore, when the first wire 31 and the second wire 32 made of different types of metal are bonded to the lead frame 2 plated with a single type of Ni, the bonding strength of the first wire 31 (wedge bonding portion 312). And variations in the bonding strength of the second wire 32 (ball bonding portion 321) can be suppressed. In addition, since it is not necessary to apply a plurality of types of plating to the lead frame 2, it is possible to avoid a decrease in the manufacturing efficiency of the semiconductor device A1.

  According to this embodiment, the wire piece 4 and the first wire 31 are both wedge-bonded to the lead frame 2, and the wire piece 4 and the first wire 31 are formed from the same first wiring member 301. Therefore, the same wedge bonding apparatus (wedge tool 6) can be used for the wire forming step and the first wire piece forming step. That is, it is possible to reduce manufacturing complexity such as using a new bonding apparatus or changing a wiring material used for wire bonding.

  According to this embodiment, the cross-sectional dimension of the wire piece 4 is approximately 300 to 400 μm, and the wire diameter of the second wire 32 is 40 to 100 μm. That is, the cross-sectional dimension of the wire piece 4 is larger than the wire diameter of the second wire 32. Therefore, the second wire 32 can be securely bonded to the wire piece 4. That is, the ball joint portion 321 of the second wire 32 can be formed on the wire piece 4.

  Next, various modifications of the semiconductor device A1 and the manufacturing method thereof according to the present embodiment will be described.

  In the present embodiment, the case where the first metal (first wire 31 and wire piece 4) is mainly composed of aluminum and the second metal (second wire 32) is composed mainly of gold has been described. It is not limited. What is necessary is just to change suitably by the compatibility of metal joining with the lead frame 2 (surface layer) as a to-be-joined body. Specifically, the combination of the lead frame 2, the first metal, and the second metal may be set to satisfy the following conditions. That is, the bonding strength between the first metal and the lead frame 2 is higher than the bonding strength when the second metal and the lead frame 2 are directly bonded, and the bonding strength between the first metal and the second metal is the second. The condition is that the bonding strength is higher than when the metal and the lead frame 2 are directly bonded. For example, in the above-described embodiment, a metal whose main component is copper may be used as the second wire 32 instead of a metal whose main component is gold. In the above embodiment, the lead frame 2 may not be plated with Ni, and the surface layer of the lead frame 2 may be copper. However, when the lead frame 2 is not subjected to Ni plating, the portion exposed from the resin package 5 is preferably plated for protection against deterioration in consideration of deterioration such as natural oxidation. Even in such a case, the above-described effects can be achieved.

  In the above embodiment, in the second wire forming step, the second wiring member 302 (second wire 32) is ball-bonded to the wire piece 4, and to the second semiconductor chip 12 (chip main surface 121). Although the case where the second wire 32 is formed by stitch bonding has been described, it may be reversed. That is, the second wiring member 302 (second wire 32) is ball bonded to the second semiconductor chip 12 (chip main surface 121) and stitch bonded to the wire piece 4 to form the second wire 32. May be. In this case, in the second wire 32, the ball joint portion 321 is joined to the second semiconductor chip 12, and the stitch joint portion 322 is joined to the wire piece 4. Therefore, in the modification, the stitch joint portion 322 corresponds to an example of a “second bonding portion”.

  Thus, when the second wire 32 is stitch-bonded to the wire piece 4, the following points should be considered. That is, in the above embodiment, the second wire 32 is ball bonded to the wire piece 4. Therefore, the ball bonding portion 321 of the second wire 32 is bonded to the wire piece 4. Since the ball joint portion 321 has a ball shape, the moving direction of the capillary 7 in the subsequent looping is not particularly limited with respect to the direction of ultrasonic vibration applied during ball bonding. That is, the second linear portion 323 can be formed in any direction with respect to the ball joint portion 321. However, when the second wire 32 is stitch-bonded to the wire piece 4, the direction of ultrasonic vibration applied at the time of the stitch bonding is limited to the direction in which the capillary 7 has moved during looping. That is, the direction of ultrasonic vibration applied during stitch bonding is limited to the direction in which the second linear portion 323 extends from the stitch joint portion 322. Therefore, the second wire 32 may be formed so that the second linear portion 323 extends from the stitch joint portion 322 along the longitudinal direction of the wire piece 4. By doing in this way, the direction where the ridge of the wire piece 4 extends and the direction of the ultrasonic vibration added at the time of stitch bonding can be made to correspond. Therefore, the pressing force at the time of stitch bonding can be efficiently transmitted to the second wire 32. Thereby, when the second wire 32 is stitch-bonded to the wire piece 4, the bonding strength between the second wire 32 and the wire piece 4 can be increased. In the formation of the second wire 32, when the direction in which the second linear portion 323 extends is predetermined, the wire piece 4 is formed so that the longitudinal direction of the wire piece 4 coincides with that direction. It is good to leave.

  FIG. 15 shows the semiconductor device A <b> 1 ′ when the second wire 32 is stitch-bonded to the wire piece 4. FIG. 15 is a plan view of the semiconductor device A1 '. 16A-C and FIG. 17 show a wire bonding structure in the semiconductor device A1 '. 16A to 16C are various cross-sectional views taken along a plane perpendicular to the longitudinal direction of the wire piece 4 in the wire bonding structure. Each of FIGS. 16A to 16C has the same conditions as those in FIGS. That is, FIG. 16A shows a wire bonding structure when the wire piece 4 is crushed by the second wire 32. FIG. 16B shows a wire bonding structure when the second wire 32 and the wire piece 4 are crushed against each other. FIG. 16C shows a wire bonding structure when the wire piece 4 is not deformed. FIG. 17 is a diagram (plan view) of the wire bonding structure viewed from the z1 direction. FIG. 17 shows a case where the cross section of the wire piece 4 is the cross section shown in FIG. 16A.

  In the semiconductor device A1 ′, as shown in FIGS. 15 and 17, the longitudinal direction of each wire piece 4 and the second linear portion from the stitch joint portion 322 in each second wire 32 joined to each wire piece 4 are used. The direction in which 323 extends coincides. That is, the second wire 32 is formed so that the second linear portion 323 extends from the stitch joint portion 322 along the longitudinal direction of the wire piece 4. In the present embodiment, two second wires 32 are joined at the second wire bonding part 222 of the second lead 2B, and the second wire 32 is connected to the second linear shape from the stitch joining part 322. Since the extending direction of the portion 323 is different, the wire piece 4 is formed for each of the two second wires 32. Further, in the wire bonding structure of the semiconductor device A1 ′, the second wire 32 (stitch joint portion 322) and the wire piece 4 are deformed similarly to FIGS. 13A to 13C as shown in FIGS. 16A to 16C. Yes. That is, when the second wire 32 is stitch bonded to the wire piece 4, the second wire 32 is deformed in the same manner as when the second wire 32 is ball bonded. Note that the wire bonding structures shown in FIGS. 16A to 16C are not limited to those shown in FIG.

  Even when the second wire 32 is stitch-bonded to the wire piece 4 as in the present modification shown above, the same effects as in the above embodiment can be obtained. In addition, when the second wire 32 is directly stitch-bonded to the object to be bonded (second wire bonding part 222), the object to be bonded may be damaged by a pressing force or ultrasonic vibration during the stitch bonding. However, in this modification, stitch bonding is performed to the object to be bonded via the wire piece 4. That is, stitch bonding is performed on the wire piece 4. Since the wire piece 4 has the same wire diameter as that of the first wire 31, the wire piece 4 is thicker than the plating layer. Accordingly, the pressing force and ultrasonic vibration applied to the joined body during stitch bonding can be reduced by the wire piece 4. Thereby, damage to a joined object can be controlled. Further, since the pressing force and ultrasonic vibration during stitch bonding can be alleviated by the wire piece 4, it is not necessary to form bumps or the like. Further, it is possible to suppress the damage to the joined body by reducing the pressing force and ultrasonic vibration during stitch bonding, but on the other hand, the bonding strength is reduced. However, when the stitch bonding is performed on the wire piece 4 as in this modification, it is not necessary to reduce the pressing force or the ultrasonic vibration, so that it is possible to suppress a decrease in the bonding strength.

  In the said embodiment, although the case where the capillary 7 was used at the 2nd wire formation process was demonstrated, it is not limited to this, You may use the wedge tool 6. FIG. In this case, the second wire 32 is wedge-bonded to the wire piece 4 and the second semiconductor chip 12. Therefore, the second wire 32 has a pair of wedge joint portions instead of the ball joint portion 321 and the stitch joint portion 322. The pair of wedge joint portions are connected by the second linear portion 323. Also in the wedge bonding, the direction of applying ultrasonic vibration is limited to the moving direction in looping, as in the case of stitch bonding using the capillary 7. Therefore, it is preferable to loop so that the longitudinal direction of the wire piece 4 coincides with the direction in which ultrasonic vibration is applied by wedge bonding. That is, in the second wire forming step, the second wire is arranged such that the direction in which the second linear portion 323 extends from the wedge joint portion joined to the wire piece 4 of the second wire 32 coincides with the longitudinal direction of the wire piece 4. 32 may be formed. Thereby, the direction where the ridge of the wire piece 4 extends and the direction where the 2nd linear part 323 extends from the wedge junction part joined to the wire piece 4 of the 2nd wire 32 can be made to correspond. Therefore, the bonding strength between the second wire 32 and the wire piece 4 can be increased. Also in this modified example, when the second wire 32 is directly wedge-bonded to the object to be joined (second wire bonding part 222), similarly to the stitch bonding, due to the pressing force and the ultrasonic vibration during the wedge bonding, The joint may be damaged. However, by performing wedge bonding via the wire piece 4 as in this modification, it is possible to suppress damage to the joined object without forming bumps or the like, as in the case of stitch bonding. Furthermore, it is possible to suppress a decrease in bonding strength.

  In the above embodiment, in the wedge 61 of the wedge tool 6, the guide groove 611 has a V-shaped cross section, but the present invention is not limited to this. For example, as shown in FIG. 18A, the guide groove 611 may have a trapezoidal cross-sectional shape. By doing so, as shown in FIG. 18A, when the first wiring member 301 is wedge-joined, the first wiring member 301 is crushed along the guide groove 611 having a trapezoidal cross section. Therefore, as shown in FIG. 18B, the wire piece 4 formed using such a wedge 61 has a flat upper surface (a surface facing z1). Thereby, the bonding of the second wire 32 to the wire piece 4 becomes easy.

  In the above embodiment, a wiring material having a circular cross section perpendicular to the major axis direction is used as the first wiring material 301, but a ribbon-shaped wiring material may be used. In this case, since the wire piece 4 is formed of a ribbon-shaped wiring material, the surface facing the z1 direction is flat. Therefore, the bonding of the second wire 32 to the wire piece 4 becomes easy.

  In the said embodiment, although the wire piece 4 demonstrated the case where it formed by wedge bonding using the wedge tool 6, it is not limited to this. For example, the wire piece 4 may be formed using the capillary 7. For example, the wire piece 4 is formed on the second wire bonding portion 222 in the same shape as a bump used for flip chip bonding or the like. Moreover, you may join the wire piece 4 to the 2nd wire bonding part 222 by stitch bonding.

  In the said embodiment, although the case where the wedge tool 6 was used at the 1st wire formation process was demonstrated, it is not limited to this, You may use the capillary 7. FIG. In this case, in the first wire forming step, the first wiring member 301 is used for ball bonding to the first semiconductor chip 11, and after looping, stitch bonding is performed to the lead frame 2 (first wire bonding portion 221). To do. Therefore, the first wire 31 has a ball joint formed by ball bonding instead of the wedge joint 311, and has a stitch joint formed by stitch bonding instead of the wedge joint 312. In this case, the stitch joint portion corresponds to an example of a “first bonding portion”. On the contrary, in the first wire forming step, the first wiring member 301 is used for ball bonding to the lead frame 2 (first wire bonding portion 221), and after looping, the first semiconductor chip 11 is bonded. Stitch bonding may be used. Therefore, the first wire 31 has a stitch joint formed by stitch bonding instead of the wedge joint 311, and has a ball joint formed by ball bonding instead of the wedge joint 312. In this case, the ball joint portion corresponds to an example of a “first bonding portion”. Note that when the first wire 31 is formed by the capillary 7 as described above, the wire piece 4 may also be formed by using the capillary 7.

  In the said embodiment, you may further perform the anodizing process process which forms an anodized film between a wire bonding process and a resin molding process. By doing in this way, since an anodic oxide film is formed in the surface of the part (electrode pad 113, the 1st wire 31, wire piece 4) whose main ingredients are aluminum, these corrosion resistance can be improved. it can.

  In the above embodiment, the case where the semiconductor chip 1 includes the plurality of first semiconductor chips 11 and the second semiconductor chips 12 has been described. However, the present invention is not limited to this. Moreover, although the case where it has the 1st-9th leads 2A-2I (9 leads) as the lead frame 2 was demonstrated to the example, it is not limited to this. That is, as long as a plurality of types of wires are used, the semiconductor device can be applied to various shapes of semiconductor devices. The number and types of semiconductor chips 1, the shape of the lead frame 2, the number of leads, etc. What is necessary is just to change suitably according to the function made into the objective. Further, instead of a lead frame structure, a chip-type semiconductor device for surface mounting may be used.

  The semiconductor device and the method for manufacturing the semiconductor device according to the present disclosure are not limited to the above-described embodiments. The specific configuration of each part of the semiconductor device of the present disclosure and the specific configuration of each process of the manufacturing method of the present disclosure can be variously modified.

The present disclosure includes the following supplementary notes.
[Appendix A1]
A semiconductor element;
A body to be electrically connected to the semiconductor element;
A first wire made of a first metal material, the first wire including a first bonding portion bonded to the object to be bonded and a first linear portion extending from the first bonding portion;
A wire piece made of the first metal and bonded to the object to be bonded;
The second wire is a second metal made of a second metal different from the first metal, the second bonding portion being joined to the joined body via the wire piece, and the second wire extending from the second bonding portion. A semiconductor device comprising: a second wire including a shaped portion.
[Appendix A2]
The second bonding part is spaced apart from the object to be joined;
The semiconductor device according to appendix A1.
[Appendix A3]
The first bonding portion and the wire piece are bonded by wedge bonding using a wedge tool, and have a press mark formed at the time of the bonding.
The semiconductor device according to appendix A1 or appendix A2.
[Appendix A4]
The shape of the wire piece is substantially the same shape as the first bonding portion.
The semiconductor device according to appendix A3.
[Appendix A5]
The second bonding portion is a ball bonding portion bonded by ball bonding.
The semiconductor device according to any one of appendices A1 to A4.
[Appendix A6]
The second bonding portion is a stitch bonding portion bonded by stitch bonding.
The semiconductor device according to any one of appendices A1 to A4.
[Appendix A7]
The wire piece has an elongated shape,
The direction in which the second linear portion extends from the stitch joint portion and the longitudinal direction of the wire piece match.
The semiconductor device according to appendix A6.
[Appendix A8]
The bonding strength between each of the first wire and the wire piece and the bonded body is based on the bonding strength between the second wire and the bonded body when the second wire is directly bonded to the bonded body. high,
The bonding strength between the wire piece and the second wire is higher than the bonding strength between the second wire and the object to be bonded when the second wire is directly bonded to the object to be bonded.
The semiconductor device according to any one of appendices A1 to A7.
[Appendix A9]
The wire diameter of the first wire is larger than the wire diameter of the second wire,
The semiconductor device according to any one of appendices A1 to A8.
[Appendix A10]
The bonded body includes a first bonded portion to which the first bonding portion is bonded, and a second bonded portion to which the second bonding portion is bonded through the wire piece,
The first bonding portion and the second bonding portion have surface layers made of the same material,
The semiconductor device according to any one of appendices A1 to A9.
[Appendix A11]
The first bonding portion and the second bonding portion are nickel-plated,
The semiconductor device according to appendix A10.
[Appendix A12]
The first metal is mainly composed of aluminum,
The second metal is mainly composed of gold or copper.
The semiconductor device according to appendix A11.
[Appendix A13]
A method for manufacturing a semiconductor device, comprising:
Forming a piece of wire by bonding a part of the first wiring material made of the first metal to the object to be bonded;
Using the first wiring material, forming a first wire including a first bonding portion bonded to the object to be bonded and a first linear portion extending from the first bonding portion;
A second wiring member comprising a second bonding material bonded to the wire piece and a second linear portion extending from the second bonding portion using a second wiring material made of a second metal different from the first metal. Forming a wire.
[Appendix A14]
In forming the wire piece, a wire guide, a wedge that presses the first wiring member sent from the wire guide against a bonding target, and a cutter that cuts the first wiring member are provided. Using a wedge tool, form the wire piece,
In forming the first wire, the first wire is formed using the wedge tool.
The manufacturing method according to appendix A13.
[Appendix A15]
Forming the wire piece
Adding ultrasonic vibration in a state in which a part of the first wiring member is pressed against the object to be bonded by the wedge, and bonding a part of the first wiring material to the object to be bonded;
Cutting the first wiring material so as to leave a part of the first wiring material, thereby forming the wire piece.
The manufacturing method according to appendix A14.
[Appendix A16]
In forming the second wire, a capillary is used to form the second wire,
Forming the second wire comprises:
Melting the second wiring member protruding from the tip of the capillary to form a molten ball;
Ball bonding for forming the second bonding portion by pressing and joining the molten ball to the wire piece;
Looping to form the second linear part by moving the capillary while pulling out the second wiring material after the ball bonding,
After the looping, stitch bonding that presses and bonds the second wiring member to the semiconductor element,
The manufacturing method according to any one of appendices A13 to A15.
[Appendix A17]
In forming the second wire, a capillary is used to form the second wire,
Forming the second wire comprises:
Ball bonding for melting the second wiring material protruding from the tip of the capillary to form a molten ball, pressing the molten ball against a semiconductor element, and bonding;
Looping to form the second linear part by moving the capillary while pulling out the second wiring material after the ball bonding,
After the looping, the second wiring member is pressed against the wire piece and joined to form the second bonding portion, and stitch bonding is included.
The manufacturing method according to any one of appendices A13 to A15.
[Appendix A18]
The wire piece has an elongated shape,
In forming the second wire, the second wire is formed by matching the direction in which the second linear portion extends from the second bonding portion and the longitudinal direction of the wire piece.
The manufacturing method according to attachment A17.
[Appendix A19]
As said 1st metal, the joint strength with said to-be-joined body is higher than the joint strength with said 2nd metal and said to-be-joined body, and the joint strength with said 2nd metal has said 2nd metal and said to-be-joined Use a material that has higher strength than the body.
The manufacturing method according to any one of appendices A13 to A18.
[Appendix A20]
The wire diameter of the first wire is larger than the wire diameter of the second wire,
The manufacturing method according to any one of appendices A13 to A19.
[Appendix A21]
The bonded body includes a first bonded portion to which the first bonding portion is bonded, and a second bonded portion to which the second bonding portion is bonded through the wire piece,
The first bonding portion and the second bonding portion have surface layers made of the same material,
The manufacturing method according to any one of appendices A13 to A20.
[Appendix A22]
Further, nickel plating is applied to the first bonding portion and the second bonding portion.
The manufacturing method according to attachment A21.
[Appendix A23]
As the first metal, a metal whose main component is aluminum is used,
As the second metal, a metal whose main component is gold or copper is used.
The manufacturing method according to appendix A22.

A1, A1 ': Semiconductor device 1: Semiconductor chip 11: First semiconductor chip 111: Chip main surface 112: Chip back surface 113: Electrode pad 12: Second semiconductor chip (semiconductor element)
121: Chip main surface 122: Chip back surface 2: Lead frame (bonded body)
2A to 2I: First to ninth leads 21: Die bonding part 211: First die bonding part 212: Second die bonding part 22: Wire bonding part 221: First wire bonding part (first bonding part)
222: Second wire bonding part (second bonding part)
23: Terminal part 24: Heat radiation part 200: Lead frame (bonded body)
201: frame 3: wire 301: first wiring member 302: second wiring member 31: first wire 311: wedge joint 312: wedge joint (first bonding part)
313: First linear portion 32: Second wire 321: Ball joint portion (second bonding portion)
322: Stitch joint (second bonding part)
323: second linear portion 33: third wire 331: ball joint portion 332: stitch joint portion 333: third linear portion 4: wire piece 411: pressed surface 412: contact surface 413: outer peripheral surface 42: fracture Section 43: Press mark 5: Resin package 6: Wedge tool 61: Wedge 611: Guide groove 611a: Inner surface 62: Wire guide 63: Cutter 7: Capillary 71: Molten ball 91: Bonding layer

  19 to 22 illustrate a semiconductor device A1 according to another embodiment of the present disclosure. The semiconductor device A1 of the present disclosure is of a type that is surface-mounted on an electrical circuit board such as an automobile or an electronic device. The semiconductor device A1 includes a plurality of semiconductor chips 1, a lead frame 2, a plurality of wires 3, an anodized film 4, and a resin package 5. FIG. 19 is a perspective view of the semiconductor device A1. FIG. 20 is a plan view of the semiconductor device A1. FIG. 21 is a side view of the semiconductor device A1, and shows the left side surface in FIG. FIG. 22 is a partial enlarged cross-sectional view of the semiconductor device A1. 19 to 21, the anodic oxide film 4 is hatched, and the resin package 5 is indicated by an imaginary line. In FIG. 22, the resin package 5 is not shown. In the following, for convenience of understanding, an orthogonal coordinate system defined by the x, y, and z directions orthogonal to each other will be defined and described. The z direction is the thickness direction of the semiconductor device A1.

  Each of the plurality of semiconductor chips 1 is a circuit element made of a semiconductor material, and is an electronic component that is the center of the function of the semiconductor device A1. In the present embodiment, the semiconductor device A1 includes a plurality of first semiconductor chips 11 and second semiconductor chips 12 as the plurality of semiconductor chips 1.

  Each of the plurality of first semiconductor chips 11 has a rectangular shape in plan view. Each first semiconductor chip 11 is a power chip such as an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a diode. However, the present invention is not limited to this. In the present embodiment, the semiconductor device A1 includes two first semiconductor chips 11. Each first semiconductor chip 11 has a chip main surface 111 and a chip back surface 112. The chip main surface 111 is a surface facing the z1 direction. The chip back surface 112 is a surface facing the z2 direction. Each first semiconductor chip 11 has an electrode pad 113.

  Each electrode pad 113 is made of pure aluminum. Each electrode pad 113 may be an aluminum alloy. Each electrode pad 113 has a pad main surface 113a, a pad back surface 113b, and a pad side surface 113c. The pad main surface 113a is a surface facing the z1 direction. In the present embodiment, the pad main surface 113a has a rectangular shape in plan view. The pad back surface 113b is a surface facing the z2 direction. The pad side surface 113c has a surface facing the x1 direction, a surface facing the x2 direction, a surface facing the y1 direction, and a surface facing the y2 direction. In each first semiconductor chip 11, the pad main surface 113 a forms part of the chip main surface 111. That is, the pad main surface 113a is at the same position as the chip main surface 111 in the z direction. The pad main surface 113a and the chip main surface 111 may be at different positions in the z direction. A wire 3 (an aluminum wire 31 to be described later) is bonded to the pad main surface 113a.

  The second semiconductor chip 12 has a rectangular shape in plan view. The second semiconductor chip 12 is an LSI chip such as a control IC, for example. However, the present invention is not limited to this. In the present embodiment, the semiconductor device A1 has one second semiconductor chip 12. The second semiconductor chip 12 has a chip main surface 121 and a chip back surface 122. The chip main surface 121 is a surface facing the z1 direction. The chip back surface 122 is a surface facing the z2 direction. A plurality of wires 3 (gold wires 32 to be described later) are bonded to the chip main surface 121.

  The lead frame 2 is made of a conductive material. An example of such a conductive material is Cu. The lead frame 2 is joined to the electrical circuit board to form a conduction path between the plurality of semiconductor chips 1 and the electrical circuit board. The lead frame 2 includes a plurality of die bonding parts 21, a plurality of wire bonding parts 22, a plurality of terminal parts 23, and a plurality of heat dissipation parts 24 as functional components.

  Each of the plurality of die bonding portions 21 is a portion that supports the semiconductor chip 1. Each die bonding portion 21 has a plate shape along the xy plane. In the present embodiment, the plurality of die bonding portions 21 include a plurality of first die bonding portions 211 and second die bonding portions 212.

  The first semiconductor chip 11 is bonded to each of the plurality of first die bonding portions 211. Each first die bonding portion 211 is formed larger than the outer shape of the first semiconductor chip 11 when viewed in the z direction. In the present embodiment, the lead frame 2 has two first die bonding portions 211. In the second die bonding part 212, the second semiconductor chip 12 is bonded. The second die bonding part 212 is formed larger than the outer shape of the second semiconductor chip 12 when viewed in the z direction. In the present embodiment, the lead frame 2 has one second die bonding part 212. The second die bonding portions 212 are located in the z1 direction from the first die bonding portions 211.

  In the present embodiment, a bonding layer 91 is interposed between each first die bonding portion 211 and each first semiconductor chip 11 supported by the first die bonding portion 211. The bonding layer 91 is made of a conductive material. Such a conductive material is, for example, solder or silver paste. Solder has a relatively high thermal conductivity. When solder is used as the bonding layer 91, heat can be efficiently transferred from the first semiconductor chip 11 to the first die bonding portion 211. Although a predetermined bonding layer is interposed between the second die bonding part 212 and the second semiconductor chip 12 supported by the second die bonding part 212, the illustration is omitted.

  Each of the plurality of wire bonding portions 22 is a portion that supports the wire 3. In the present embodiment, the plurality of wire bonding units 22 includes a plurality of first wire bonding units 221 and a plurality of second wire bonding units 222.

  An aluminum wire 31 (described later) is bonded to each of the plurality of first wire bonding portions 221. Each first wire bonding portion 221 is subjected to Ni plating in consideration of bonding with the aluminum wire 31. In the present embodiment, the lead frame 2 has two first wire bonding portions 221. A gold wire 32 (described later) is bonded to each of the plurality of second wire bonding portions 222. Each second wire bonding portion 222 is subjected to Ag plating in consideration of bonding with the gold wire 32. In the present embodiment, the lead frame 2 has seven second wire bonding portions 222.

  The plurality of terminal portions 23 are terminals that are electrically connected to the electrical circuit board. That is, the plurality of terminal portions 23 function as connector pins of the semiconductor device A1. Each of the plurality of terminal portions 23 is exposed from the resin package 5. The plurality of terminal portions 23 are arranged in the y direction. Further, the plurality of terminal portions 23 are located in the x1 direction from the resin package 5. Each terminal portion 23 is bent. In the present embodiment, the lead frame 2 has nine terminal portions 23.

  Each of the plurality of heat radiating portions 24 is a portion that releases heat generated in the semiconductor chip 1 to the outside. Each heat dissipating part 24 is exposed from the resin package 5. In the present embodiment, each heat radiating part 24 is connected to each first die bonding part 211. The plurality of heat dissipating parts 24 are arranged in the y direction and are located in the x2 direction from the resin package 5 in a plan view. In the present embodiment, since the first semiconductor chip 11 is a power chip, it generates a large amount of heat. Therefore, the plurality of heat radiating portions 24 are provided mainly for releasing heat generated in the first semiconductor chip 11. In the present embodiment, the lead frame 2 has two heat radiating portions 24. The plurality of heat radiating portions 24 may be a part of the lead frame 2 or may be formed by joining members different from the lead frame 2.

  The lead frame 2 includes a plurality of leads. In the present embodiment, the semiconductor device A1 has nine leads (first to ninth leads 2A to 2I) spaced apart from each other as the lead frame 2.

  The first lead 2 </ b> A has a terminal part 23, a first die bonding part 211, and a heat radiating part 24. In the first lead 2A, these are connected and formed integrally. As shown in FIGS. 19 and 21, the first lead 2 </ b> A is bent at a portion connecting the terminal portion 23 and the first die bonding portion 211. The first lead 2 </ b> A supports the first semiconductor chip 11.

  The second lead 2B has a terminal portion 23 and a second wire bonding portion 222. In the second lead 2B, these are connected and formed integrally. A gold wire 32 is bonded to the second lead 2B. The third lead 2C, the fifth lead 2E, the sixth lead 2F, and the seventh lead 2G are the same as the second lead 2B.

  The fourth lead 2D has a terminal portion 23, a second wire bonding portion 222, and a second die bonding portion 212. In the fourth lead 2D, these are connected and formed integrally. The fourth lead 2D supports the second semiconductor chip 12. A gold wire 32 is joined to the fourth lead 2D.

  The eighth lead 2 </ b> H has a terminal portion 23, a first wire bonding portion 221, and a second wire bonding portion 222. In the eighth lead 2H, these are connected and formed integrally. An aluminum wire 31 and a gold wire 32 are joined to the eighth lead 2H.

  The ninth lead 2 </ b> I includes a terminal portion 23, a first die bonding portion 211, a first wire bonding portion 221, and a heat dissipation portion 24. In the ninth lead 2I, these are connected and formed integrally. As shown in FIGS. 19 and 21, the ninth lead 2 </ b> I is bent at a portion connecting the terminal portion 23 and the first die bonding portion 211. The ninth lead 2I supports the first semiconductor chip 11. An aluminum wire 31 is bonded to the ninth lead 2I.

  Each of the plurality of wires 3 connects the first semiconductor chip 11 and the second semiconductor chip 12 to the lead frame 2. In the present embodiment, the plurality of wires 3 include a plurality of aluminum wires 31 and a plurality of gold wires 32.

  Each of the plurality of aluminum wires 31 is an aluminum alloy to which any of iron, silicon, and nickel is added. Each aluminum wire 31 may be pure aluminum. Each aluminum wire 31 has one end bonded to the first semiconductor chip 11 and the other end bonded to the lead frame 2. In the present embodiment, each aluminum wire 31 has a linear shape in which the cross section perpendicular to the longitudinal direction is a circle, but it may be in a ribbon shape. Moreover, although the wire diameter of each aluminum wire 31 is 300-400 micrometers, it is not limited to this. Each aluminum wire 31 is covered with an anodized film 4. However, in each aluminum wire 31, the surface in contact with the electrode pad 113 and the surface in contact with the first wire bonding portion 221 are not covered with the anodized film 4. In the present embodiment, the semiconductor device A1 has two aluminum wires 31.

  Each of the plurality of gold wires 32 is made of gold. Each gold wire 32 has one end bonded to the second semiconductor chip 12 (chip main surface 121) and the other end connected to the lead frame 2 (second wire bonding portion 222) or the first semiconductor chip 11 (chip main surface 111). ) Is bonded. In the present embodiment, the semiconductor device A1 has eleven gold wires 32.

  The anodized film 4 has a laminated structure. FIG. 23 shows a laminated structure of the anodic oxide film 4. The anodic oxide film 4 has a barrier layer 4B and a porous layer 4C in its laminated structure. The barrier layer 4B is laminated on the aluminum wire 31 and the electrode pad 113 as the aluminum substrate 4A. The porous layer 4C is laminated on the barrier layer 4B. The porous layer 4C has a plurality of fine holes (bore) 4D.

  The anodized film 4 has a wire covering portion 41 and a pad covering portion 42. The wire covering portion 41 covers the aluminum wire 31. The wire covering portion 41 is formed over the entire length of the aluminum wire 31. The pad covering portion 42 covers the electrode pad 113 (pad main surface 113a) of the first semiconductor chip 11. The pad covering portion 42 coincides with the pad main surface 113a when viewed in the z direction. The wire covering portion 41 and the pad covering portion 42 are integrally formed. The wire covering portion 41 is formed by growing from the surface of the aluminum wire 31 in an anodic oxidation process described later. Therefore, the wire covering portion 41 is integral with the aluminum wire 31. The pad covering portion 42 is formed by growing from the surface of the electrode pad 113 in the anodizing process. Therefore, the pad covering portion 42 is integral with the electrode pad 113. In this embodiment, the anodic oxide film 4 has a thickness of 1000 to 2000 mm.

  The resin package 5 covers the plurality of semiconductor chips 1, a part of the lead frame 2, the plurality of wires 3, and the anodized film 4. Since the anodized film 4 covers the aluminum wire 31, it can be said that the resin package 5 covers the aluminum wire 31. The resin package 5 is a thermosetting synthetic resin having electrical insulation. In this embodiment, it is a black epoxy resin. Further, the resin package 5 has a rectangular shape in plan view.

  Next, a method for manufacturing the semiconductor device A1 according to the embodiment of the present disclosure will be described with reference to FIGS. The manufacturing method according to this embodiment includes a lead frame pre-process, a die bonding process, a wire bonding process, an anodizing process, a resin molding process, and a lead frame post-process. The semiconductor device A1 is manufactured through the plurality of steps. In the present embodiment, the steps described above are performed in the order described above.

  In the lead frame pre-process, preparation for forming the lead frame 2 having the above-described configuration is performed. Specifically, in the lead frame pre-process, a copper metal plate is prepared, and the copper metal plate is punched. The punching process may be performed using a known method. Thereby, the lead frame 200 shown in FIG. 24 is obtained. The lead frame 200 includes a frame 201 and a plurality of leads (first to ninth leads 2A to 2I) supported by the frame 201. The first to ninth leads 2A to 2I are formed with portions corresponding to the die bonding portion 21, the wire bonding portion 22, the terminal portion 23, and the heat dissipation portion 24 described above. At this stage, the lead frame 200 has a plate shape and is not bent.

  Next, the lead frame 200 is bent. In the bending process, the lead frame 200 is bent so that the plurality of first die bonding portions 211 are translated in the z2 direction. Accordingly, the plurality of first die bonding portions 211 are positioned in the z2 direction with respect to the second die bonding portion 212. Thereafter, various plating processes are performed on necessary portions. In the present embodiment, Ni plating is applied to the first wire bonding portion 221, and Ag plating is applied to the second wire bonding portion 222. In the lead frame pre-process, punching and bending may be performed simultaneously.

  Subsequently, in the die bonding process, a plurality of semiconductor chips 1 are die bonded to the die bonding portion 21 of the lead frame 200. In the present embodiment, each first semiconductor chip 11 is disposed on each first die bonding portion 211 via a bonding layer 91. Thereby, each first semiconductor chip 11 is bonded to each first die bonding portion 211. Further, the second semiconductor chip 12 is disposed on the second die bonding portion 212 via a bonding layer (not shown). As a result, the second semiconductor chip 12 is bonded to the second die bonding part 212. In the die bonding step, the technique is not limited as long as a plurality of semiconductor chips 1 can be die bonded at predetermined positions.

  Subsequently, in the wire bonding step, the plurality of wires 3 are wire-bonded to the lead frame 200 and the plurality of semiconductor chips 1 bonded to the lead frame 200. The wire bonding is performed using a known wire bonder. In the wire bonding step, one end of each aluminum wire 31 is bonded to the electrode pad 113 (pad main surface 113a) of the first semiconductor chip 11, and the other end is bonded to the first wire bonding portion 221. Further, one end of each gold wire 32 is bonded to the second semiconductor chip 12, and the other end is bonded to the second wire bonding portion 222 or the chip main surface 111 of the first semiconductor chip 11. In this embodiment, the aluminum wire 31 is joined using the wedge bonding method, and the gold wire 32 is joined using the ball bonding method. The lead frame 200 shown in FIG. 25 is obtained by the die bonding process and the wire bonding process.

  Subsequently, in the anodizing process, the lead frame 200 (see FIG. 25) after the wire bonding process is anodized to form the anodized film 4. FIG. 26 shows an example of the anodizing process. Specifically, the lead frame 200 as the anode and the cathode 71 are immersed in the electrolytic solution 72, and a voltage is applied between the anode and the cathode 71. Then, a chemical reaction occurs in a portion where the aluminum wire 31 and the electrode pad 113 which are aluminum materials are exposed, and the oxide film (anodized film 4) grows while the aluminum wire 31 and the electrode pad 113 are dissolved. By the growth of the oxide film, the barrier layer 4B and the porous layer 4C are formed in this order on the aluminum wire 31 and the electrode pad 113 as the aluminum substrate 4A. At this time, an oxide film simultaneously grows on both the aluminum wire 31 and the electrode pad 113, and the wire covering portion 41 and the pad covering portion 42 are integrally formed. The reaction does not occur in the lead frame 2 made of copper or the gold wire 32 made of gold. That is, the anodic oxide film 4 is not formed on the lead frame 2 or the gold wire 32. In the present embodiment, the lead frame 200 shown in FIG. 27 is obtained by the anodic oxidation process. In FIG. 27, the portion where the anodized film 4 is formed is hatched. The film thickness of the anodic oxide film 4 varies depending on conditions such as processing time (time of immersion in the electrolytic solution 72) and the applied voltage.

  The anodizing method is classified according to the type of the electrolytic solution 72, for example. The classification according to the type of the electrolytic solution 72 includes an acidic bath type, an alkaline bath type, an organic acid bath type, and a hard film type. In the present embodiment, an alkaline solution is used as the electrolytic solution 72, but is not limited thereto. Examples of such an alkaline solution (electrolytic solution 72) include ammonia-fluoride, alkali-peroxide, and sodium phosphate. Examples of the acidic solution used in the acidic bath type include sulfuric acid, oxalic acid, chromic acid, and boric acid. Further, it is also classified according to the type of voltage (DC voltage or AC voltage) applied to the anode and cathode 71. In the present embodiment, a DC voltage is applied.

  In the resin molding process, the resin package 5 is formed. In the present embodiment, it is formed by molding. In the resin molding process, the lead frame 200 (see FIG. 27) after the anodizing process is pressed by a mold (not shown), and a resin material is injected into the cavity of the mold. Then, the resin material is cured to form the resin package 5.

  In the lead frame post-process, a process for making the lead frame 200 after the resin molding process into the semiconductor device A1 shown in FIGS. 19 to 21 is performed. For this reason, in the lead frame post-process, cutting (cut-out) and bending are performed. In the cutting process, a portion where the first to ninth leads 2A to 2I and the frame 201 are connected is removed by cutting along a cutting line CL (dotted line) shown in FIG. Then, in the bending process, the portion of the first to ninth leads 2A to 2I protruding from the resin package 5 (terminal portion 23) is bent so that the tip portion in the x2 direction is translated in the z2 direction. Thereby, the some terminal part 23 makes the shape bent.

  The semiconductor device A1 shown in FIGS. 19 to 22 is obtained by sequentially performing the steps described above.

  According to the present embodiment, each aluminum wire 31 is covered with the anodized film 4 (wire covering portion 41). Thereby, each aluminum wire 31 is protected by the anodized film 4. The inventor's test has found that the anodic oxide film 4 can suppress the occurrence of pitting corrosion with respect to the temperature cycle. Therefore, bonding failure and disconnection due to damage of the aluminum wire 31 can be suppressed. That is, the reliability with respect to the temperature cycle of the semiconductor device A1 can be improved. Further, when aluminum is exposed to air, a natural oxide film (aluminum oxide film) is formed, and the natural oxide film can improve corrosion resistance. However, the natural oxide film is very thin, and the film thickness cannot be increased further. For example, the natural oxide film has a thickness of about 50 to 200 mm. Therefore, the improvement in corrosion resistance is limited. On the other hand, the anodic oxide film 4 has a film thickness of about 1000 to 2000 mm as described above, and is very thick compared to the natural oxide film. Therefore, the corrosion resistance can be further improved as compared with the case where a natural oxide film is formed on the aluminum wire 31.

  According to this embodiment, in the anodizing process, the entire lead frame 200 after the die bonding process and the wire bonding process is immersed in the electrolytic solution 72 (see FIG. 26). As a result, the anodic oxide film 4 (pad coating portion 42) is formed not only on the aluminum wire 31 but also on the electrode pad 113 whose main component is aluminum. Therefore, since the pad main surface 113a of the electrode pad 113 can also be protected by the anodic oxide film 4, corrosion of the pad main surface 113a can also be suppressed. Further, the corrosion of the pad main surface 113a of the electrode pad 113 can reach the pad side surface 113c and the pad back surface 113b through the interface of the electrode pad 113. As a result, the bonding strength of the electrode pad 113 is reduced, and the electrode pad 113 may be peeled off from the first semiconductor chip 11. Therefore, corrosion of the pad side surface 113c and the pad back surface 113b can be suppressed by protecting the pad main surface 113a of the electrode pad 113 with the anodic oxide film 4 (pad covering portion 42). That is, peeling of the electrode pad 113 can be suppressed.

  According to the present embodiment, the wire covering portion 41 and the pad covering portion 42 are integrally formed in the anodized film 4. Thereby, the joining strength between the aluminum wire 31 and the first semiconductor chip 11 (electrode pad 113) can be improved.

  According to this embodiment, the wire bonding process is performed before the anodizing process. For example, since the anodized aluminum wire 31 (the aluminum wire 31 covered with the anodized film 4) cannot be bonded due to the influence of the anodized film 4, the anodized film 4 needs to be removed. Therefore, troublesome processing is required. Therefore, the same method as the conventional bonding of the aluminum wire 31 can be used by wire bonding the aluminum wire 31 before the anodic oxide film 4 is formed. Thereby, the said troublesome process becomes unnecessary.

  According to this embodiment, the alkaline electrolytic solution 72 is used in the anodizing process. In the anodizing process, since the entire lead frame 200 is immersed in the electrolytic solution 72 as shown in FIG. 26, parts other than the aluminum wire 31 are also immersed in the electrolytic solution 72. That is, the lead frame 200 (2) is also immersed in the electrolytic solution 72. Since the lead frame 200 (2) is made of copper, if the acidic electrolyte solution 72 is used, the lead frame 200 (2) may be deteriorated. Therefore, by using the alkaline electrolytic solution 72, the corrosion of the lead frame 200 (2) can be reduced as compared with the acidic electrolytic solution 72.

  Next, various modifications of the semiconductor device A1 and the manufacturing method thereof according to the present embodiment will be described.

  In the above embodiment, a treatment for sealing the plurality of holes 4D formed in the porous layer 4C may be further added after the anodizing treatment step. The sealing process is a process of sealing the plurality of holes 4D of the porous layer 4C laminated on the aluminum base 4A (the aluminum wire 31 and the electrode pad 113) by the anodizing process. Examples of the sealing treatment method include a hydration sealing method and an inorganic filling sealing method. The hydration sealing method is a method in which water molecules are taken into the holes 4D, and the porous holes 4D are closed by volume expansion in the holes 4D, such as a pressurized water vapor sealing type (temperature: 110 to 140 ° C.) There is a water sealing type (temperature: 95 ° C. or more). The inorganic filling and sealing method is a method in which a metal salt such as nickel, cobalt, or chromium or a fluoride of these metal salts is adsorbed as a metal salt hydroxide near the opening of the hole 4D to close the hole 4D. There are a two-stage sealing type using a metal salt and a low-temperature sealing type in which a fluoride is allowed to coexist with a metal salt. FIG. 28 shows the laminated structure of the anodic oxide film 4 after the sealing treatment by the hydration sealing method. As FIG. 28 shows, the hydrate 6 is formed by the sealing process compared with FIG. The hydrate 6 is made of, for example, aluminum hydroxide. As shown in FIG. 28, the hydrate 6 is filled in the vicinity of the openings of the plurality of holes 4D, and the openings of the plurality of holes 4D are closed. It should be noted that the opening of each hole 4D is not completely closed but is included in the “sealing” even if it is narrow. Since the hydrate 6 is filled in the vicinity of the opening as described above, the thickness does not change between the anodizing treatment and the sealing treatment. In addition, the hydrate 6 may be formed in layers on the porous layer 4C. By performing the sealing treatment as described above, the surface of the anodic oxide film 4 becomes chemically more stable (inactive) and does not easily react with oxygen or other chemical substances. Therefore, the corrosion resistance of the aluminum wire 31 is further improved.

  In the above embodiment, the case where the anodic oxide film 4 has the porous layer 4C in which the plurality of holes 4D are formed has been described, but the porous layer 4C may not be formed depending on the method of anodizing treatment. Therefore, the anodic oxide film 4 may not have the porous layer 4C.

  In the above embodiment, the case where the semiconductor chip 1 includes the plurality of first semiconductor chips 11 and the second semiconductor chips 12 has been described. However, the present invention is not limited to this. Moreover, although the case where it has the 1st-9th leads 2A-2I (9 leads) as the lead frame 2 was demonstrated to the example, it is not limited to this. What is necessary is just to change suitably according to the objective function of semiconductor device A1, such as the number and kind of the semiconductor chip 1, and the shape of the lead frame 2 and the number of leads. For example, when the semiconductor device A1 is a discrete semiconductor of MOSFET, one MOSFET is bonded to the lead frame 2 as the semiconductor chip 1. The number of leads (terminal portions 23) may be three.

  In the above embodiment, the semiconductor device A1 having a lead frame structure has been described. However, the semiconductor device A1 can be applied to various semiconductor devices using wires whose main component is aluminum. For example, a chip-type semiconductor device for surface mounting instead of a lead frame structure can be applied as long as a wire whose main component is aluminum is used.

  The semiconductor device and the manufacturing method thereof according to the present disclosure are not limited to the above-described embodiments. The specific configuration of each part of the semiconductor device of the present disclosure and the specific configuration of each process of the manufacturing method can be varied in design in various ways.

The present disclosure includes the following supplementary notes.
[Appendix B1]
A semiconductor element;
An aluminum wire having one end bonded to the semiconductor element;
An anodized film having a wire coating covering the aluminum wire;
A sealing resin covering the semiconductor element and the anodized film;
A semiconductor device comprising:
[Appendix B2]
The semiconductor element has an electrode pad whose main component is aluminum,
The electrode pad has a pad main surface to which one end of the aluminum wire is bonded,
The anodic oxide film further has a pad covering portion that covers the pad main surface,
The semiconductor device according to appendix B1.
[Appendix B3]
In the anodized film, the wire coating part and the pad coating part are integrally formed,
The semiconductor device according to appendix B2.
[Appendix B4]
The anodized film has a porous layer in which a plurality of holes are formed,
A hydrate that seals the plurality of holes;
The semiconductor device according to any one of appendices B1 to B3.
[Appendix B5]
Iron, silicon, or nickel is added to the aluminum wire,
The semiconductor device according to any one of appendices B1 to B4.
[Appendix B6]
An electrode electrically connected to the semiconductor element;
The electrode has a die bonding part to which the semiconductor element is bonded inside the sealing resin and a terminal part exposed from the sealing resin.
The semiconductor device according to any one of appendices B1 to B5.
[Appendix B7]
The electrode is a lead frame;
The semiconductor device according to appendix B6.
[Appendix B8]
Bonding one end of an aluminum wire to the semiconductor element;
Forming an anodized film covering the aluminum wire;
Forming a sealing resin covering the semiconductor element and the anodized film;
A method for manufacturing a semiconductor device, comprising:
[Appendix B9]
The semiconductor element has an electrode pad whose main component is aluminum,
In the wire bonding step, one end of the aluminum wire is bonded to the electrode pad,
In forming the anodized film, an anodized film covering the electrode pad is formed.
The manufacturing method according to appendix B8.
[Appendix B10]
Forming the anodized film is performed after joining one end of the aluminum wire to the semiconductor element and before forming the sealing resin.
The manufacturing method according to appendix B9.
[Appendix B11]
In joining one end of the aluminum wire to the semiconductor element, a wedge bonding method is used.
The manufacturing method according to any one of Supplementary Notes B8 to B10.
[Appendix B12]
The anodized film has a porous layer in which a plurality of holes are formed,
Further comprising sealing the plurality of pores with a hydrate.
The manufacturing method according to any one of Appendix B8 to Appendix B11.
[Appendix B13]
The semiconductor device further includes an electrode electrically connected to the semiconductor element,
Further comprising bonding the semiconductor element to the electrode;
The manufacturing method according to any one of Supplementary Notes B8 to B12.
[Appendix B14]
In forming the anodic oxide film, the electrode and the cathode as an anode are immersed in an electrolytic solution, and a DC voltage is applied to the anode and the cathode.
The manufacturing method according to appendix B13.
[Appendix B15]
In forming the anodized film, an alkaline solution is used as the electrolytic solution.
The manufacturing method according to attachment B14.

A1: Semiconductor device 1: Semiconductor chip 11: First semiconductor chip 111: Chip main surface 112: Chip back surface 113: Electrode pad 113a: Pad main surface 113b: Pad back surface 113c: Pad side surface 12: Second semiconductor chip 121: Chip main Surface 122: Chip back surface 2: Lead frames 2A to 2I: First to ninth leads 21: Die bonding portion 211: First die bonding portion 212: Second die bonding portion 22: Wire bonding portion 221: First wire bonding portion 222: 2nd wire bonding part 23: Terminal part 24: Heat radiation part 200: Lead frame 201: Frame 3: Wire 31: Aluminum wire 32: Gold wire 4: Anodized film 4A: Aluminum base 4B: Barrier layer 4C: Porous layer 4D: Hole 41: Wire covering part 42: Par De covering section 5: the resin package 6: hydrate 71: cathode 72: electrolyte 91: bonding layer

Claims (23)

A semiconductor element;
A body to be electrically connected to the semiconductor element;
A first wire made of a first metal material, the first wire including a first bonding portion bonded to the object to be bonded and a first linear portion extending from the first bonding portion;
A wire piece made of the first metal and bonded to the object to be bonded;
The second wire is a second metal made of a second metal different from the first metal, the second bonding portion being joined to the joined body via the wire piece, and the second wire extending from the second bonding portion. A semiconductor device comprising: a second wire including a shaped portion. The second bonding part is spaced apart from the object to be joined;
The semiconductor device according to claim 1. The first bonding portion and the wire piece are bonded by wedge bonding using a wedge tool, and have a press mark formed at the time of the bonding.
The semiconductor device according to claim 1 or 2. The shape of the wire piece is substantially the same shape as the first bonding portion.
The semiconductor device according to claim 3. The second bonding portion is a ball bonding portion bonded by ball bonding.
The semiconductor device according to claim 1. The second bonding portion is a stitch bonding portion bonded by stitch bonding.
The semiconductor device according to claim 1. The wire piece has an elongated shape,
The direction in which the second linear portion extends from the stitch joint portion and the longitudinal direction of the wire piece match.
The semiconductor device according to claim 6. The bonding strength between each of the first wire and the wire piece and the bonded body is based on the bonding strength between the second wire and the bonded body when the second wire is directly bonded to the bonded body. high,
The bonding strength between the wire piece and the second wire is higher than the bonding strength between the second wire and the object to be bonded when the second wire is directly bonded to the object to be bonded.
The semiconductor device according to claim 1. The wire diameter of the first wire is larger than the wire diameter of the second wire,
9. The semiconductor device according to any one of claims 1 to 8. The bonded body includes a first bonded portion to which the first bonding portion is bonded, and a second bonded portion to which the second bonding portion is bonded through the wire piece,
The first bonding portion and the second bonding portion have surface layers made of the same material,
The semiconductor device according to claim 1. The first bonding portion and the second bonding portion are nickel-plated,
The semiconductor device according to claim 10. The first metal is mainly composed of aluminum,
The second metal is mainly composed of gold or copper.
The semiconductor device according to claim 11. A method for manufacturing a semiconductor device, comprising:
Forming a piece of wire by bonding a part of the first wiring material made of the first metal to the object to be bonded;
Using the first wiring material, forming a first wire including a first bonding portion bonded to the object to be bonded and a first linear portion extending from the first bonding portion;
A second wiring member comprising a second bonding material bonded to the wire piece and a second linear portion extending from the second bonding portion using a second wiring material made of a second metal different from the first metal. Forming a wire. In forming the wire piece, a wire guide, a wedge that presses the first wiring member sent from the wire guide against a bonding target, and a cutter that cuts the first wiring member are provided. Using a wedge tool, form the wire piece,
In forming the first wire, the first wire is formed using the wedge tool.
The manufacturing method according to claim 13. Forming the wire piece
Adding ultrasonic vibration in a state in which a part of the first wiring member is pressed against the object to be bonded by the wedge, and bonding a part of the first wiring material to the object to be bonded;
Cutting the first wiring material so as to leave a part of the first wiring material, thereby forming the wire piece.
The manufacturing method according to claim 14. In forming the second wire, a capillary is used to form the second wire,
Forming the second wire comprises:
Melting the second wiring member protruding from the tip of the capillary to form a molten ball;
Ball bonding for forming the second bonding portion by pressing and joining the molten ball to the wire piece;
Looping to form the second linear part by moving the capillary while pulling out the second wiring material after the ball bonding,
After the looping, stitch bonding that presses and bonds the second wiring member to the semiconductor element,
The manufacturing method according to any one of claims 13 to 15. In forming the second wire, a capillary is used to form the second wire,
Forming the second wire comprises:
Ball bonding for melting the second wiring material protruding from the tip of the capillary to form a molten ball, pressing the molten ball against a semiconductor element, and bonding;
Looping to form the second linear part by moving the capillary while pulling out the second wiring material after the ball bonding,
After the looping, the second wiring member is pressed against the wire piece and joined to form the second bonding portion, and stitch bonding is included.
The manufacturing method according to any one of claims 13 to 15. The wire piece has an elongated shape,
In forming the second wire, the second wire is formed by matching the direction in which the second linear portion extends from the second bonding portion and the longitudinal direction of the wire piece.
The manufacturing method according to claim 17. As said 1st metal, the joint strength with said to-be-joined body is higher than the joint strength with said 2nd metal and said to-be-joined body, and the joint strength with said 2nd metal has said 2nd metal and said to-be-joined Use a material that has higher strength than the body.
The manufacturing method according to any one of claims 13 to 18. The wire diameter of the first wire is larger than the wire diameter of the second wire,
The manufacturing method as described in any one of Claim 13 thru | or 19. The bonded body includes a first bonded portion to which the first bonding portion is bonded, and a second bonded portion to which the second bonding portion is bonded through the wire piece,
The first bonding portion and the second bonding portion have surface layers made of the same material,
The manufacturing method according to any one of claims 13 to 20. Further, nickel plating is applied to the first bonding portion and the second bonding portion.
The manufacturing method according to claim 21. As the first metal, a metal whose main component is aluminum is used,
As the second metal, a metal whose main component is gold or copper is used.
The manufacturing method according to claim 22.

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