JP7215320B2 - semiconductor equipment - Google Patents

Description

The technology disclosed in this specification relates to a semiconductor device.

A semiconductor device is disclosed in Japanese Patent Laid-Open No. 2002-200012. This semiconductor device includes a semiconductor element, a sealing body that seals the semiconductor element, and a conductor member that is joined to the semiconductor element inside the sealing body. The semiconductor element and the conductor member are joined via a solder layer.

JP 2009-146950 A

When the semiconductor element and the conductor member are soldered together, surplus solder may overflow from between the semiconductor element and the conductor member. At this time, if excess solder wets and spreads toward the semiconductor element, there is a risk of causing problems such as a short circuit or insulation failure in the semiconductor element. For this reason, it is preferable that the surplus solder wets and spreads along the conductor member. However, when the surface of the conductor member is widely covered with solder, the adhesion between the conductor member and the sealing body is deteriorated, which may deteriorate the durability of the semiconductor device, for example. This specification provides a technique capable of suppressing such events and improving the durability of the semiconductor device.

A semiconductor device disclosed in this specification includes a semiconductor element, a sealing body that seals the semiconductor element, and a conductor member that is bonded to the semiconductor element via a solder layer inside the sealing body. The conductor member has a plate-like portion and a protruding portion that protrudes from one surface of the plate-like portion. The protruding portion has a bonding surface in contact with the solder layer and a side surface extending from the peripheral edge of the bonding surface. One surface of the plate-shaped portion is provided with an outer peripheral groove extending along the peripheral edge of the protruding portion. A guide groove extending from the peripheral edge of the joint surface to the outer peripheral groove is provided on the side surface of the projecting portion.

According to the above structure, when the semiconductor element and the conductor member are soldered together, surplus solder overflowing from the joint surface is guided to the outer peripheral groove away from the semiconductor element through the guide groove extending from the joint surface. . This suppresses excess solder from wetting and spreading toward the semiconductor element. In addition, by collecting excess solder in the guide groove, it is avoided that the side surface of the protrusion is widely covered with solder. This significantly improves the durability of the semiconductor device.

1 is a plan view showing the appearance of a semiconductor device 10 of an embodiment; FIG. Sectional drawing in the II-II line in FIG. FIG. 10 is a diagram showing a side surface 32 of the projecting portion 20 of the second conductor plate 19; 4 is a diagram showing a joint surface 30 of a projecting portion 20 of a second conductor plate 19; FIG.

In an embodiment of the present technology, the sides of the protrusion may have multiple planes and multiple corners, such as a prism or truncated pyramid. In this case, a guide groove may be provided along at least one of the plurality of corners. However, the number, position and shape of the guide grooves are not particularly limited.

In one embodiment of the present technology, the aforementioned slope may be slanted such that it displaces outward as it moves away from the joint surface. That is, the side surface may be frustum-shaped. According to such a configuration, by increasing the area of the side surface while maintaining the area of the joint surface, it is possible to deal with a larger amount of surplus solder.

A semiconductor device 10 of an embodiment will be described with reference to FIGS. 1 to 4. FIG. The semiconductor device 10 of the present embodiment is employed, for example, in a power control device for an electric vehicle, and can form part of a power conversion circuit such as a converter or an inverter. An electric vehicle in this specification broadly means a vehicle having a motor for driving the wheels. Including fuel cell vehicles, etc.

As shown in FIGS. 1 and 2, the semiconductor device 10 includes a semiconductor element 12 and a sealing body 14 that seals the semiconductor element 12 . The sealing body 14 is made of an insulating material. Although not particularly limited, the sealing body 14 in this embodiment is made of a sealing material such as epoxy resin. The sealing body 14 generally has a plate shape and has an upper surface 14a, a lower surface 14b, a first end surface 14c, a second end surface 14d, a first side surface 14e and a second side surface 14f.

The semiconductor element 12 is a power semiconductor element and has a semiconductor substrate 12a, an upper surface electrode 12b and a lower surface electrode 12c. The upper electrode 12b is located on the upper surface of the semiconductor substrate 12a, and the lower electrode 12c is located on the lower surface of the semiconductor substrate 12a. The upper surface electrode 12b and the lower surface electrode 12c are electrically connected to each other through the semiconductor substrate 12a. Although not particularly limited, the semiconductor element 12 in this embodiment is a switching element, and can selectively turn on and off between the upper surface electrode 12b and the lower surface electrode 12c. The type of semiconductor substrate 12a is not particularly limited. The semiconductor substrate 12a may be, for example, a silicon substrate, a silicon carbide substrate, or a nitride semiconductor substrate. The upper electrode 12b and the lower electrode 12c can be made of one or more kinds of metals such as aluminum, nickel, or gold.

As an example, the semiconductor element 12 in this embodiment is an RC (Reverse Conducting)-IGBT in which an IGBT (Insulated Gate Bipolar Transistor) and a diode are integrated. The upper electrode 12b is connected to the emitter of the IGBT and the anode of the diode, and the lower electrode 12c is connected to the collector of the IGBT and the cathode of the diode. As another embodiment, the semiconductor element 12 may be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). In this case, the top electrode 12b is connected to the source of the MOSFET and the bottom electrode 12c is connected to the drain of the MOSFET.

The semiconductor device 10 further includes a first conductor plate 16 and a second conductor plate 19 . The first conductor plate 16 and the second conductor plate 19 face each other with the semiconductor element 12 interposed therebetween. The first conductor plate 16 and the second conductor plate 19 are made of a conductor such as metal. As an example, the first conductor plate 16 and the second conductor plate 19 in this embodiment are made of copper, and the surfaces thereof are plated with nickel. The first conductor plate 16 and the second conductor plate 19 are held by the sealing body 14 and face each other with the semiconductor element 12 interposed therebetween. The upper surface 16 a of the first conductor plate 16 is located inside the sealing body 14 and electrically connected to the lower surface electrode 12 c of the semiconductor element 12 . The lower surface 16b of the first conductor plate 16 is exposed to the lower surface 14b of the sealing body 14. As shown in FIG. As a result, the first conductor plate 16 constitutes a part of the circuit electrically connected to the semiconductor element 12, and can also function as a heat sink for releasing the heat of the semiconductor element 12 to the outside. The upper surface 16a of the first conductor plate 16 and the lower electrode 12c of the semiconductor element 12 are joined by soldering, and the solder layer 13 is formed between the first conductor plate 16 and the semiconductor element 12. It is

The second conductor plate 19 has a plate-like portion 18 and a projecting portion 20 . The plate-like portion 18 generally has the same or similar shape as the first conductor plate 16 . An upper surface 18 a of the plate-like portion 18 is exposed on the upper surface 14 a of the sealing body 14 , and a lower surface 18 b of the plate-like portion 18 faces the first conductor plate 16 inside the sealing body 14 . The protruding portion 20 protrudes toward the semiconductor element 12 from the lower surface 18 b of the plate-like portion 18 . The projecting portion 20 is electrically connected to the upper surface electrode 12b of the semiconductor element 12 . Specifically, the projecting portion 20 and the upper surface electrode 12b of the semiconductor element 12 are joined by soldering, and the solder layer 15 is formed therebetween. An outer peripheral groove 28 is formed along the periphery of the projecting portion 20 in the lower surface 18 b of the plate-like portion 18 . The outer peripheral groove 28 is provided to accommodate excess solder in soldering the second conductor plate 19 and the semiconductor element 12 .

Semiconductor device 10 includes a first power terminal 22 , a second power terminal 24 , and a plurality of signal terminals 26 . The first power terminal 22 and the second power terminal 24 protrude from the first end surface 14 c of the encapsulant 14 . The first power terminal 22 is electrically connected to the first conductor plate 16 inside the sealing body 14 , and the second power terminal 24 is electrically connected to the second conductor plate 19 inside the sealing body 14 . It is connected to the. Thereby, the first power terminal 22 and the second power terminal 24 are electrically connected via the semiconductor element 12 . A plurality of signal terminals 26 protrude from the second end face 14 d of the sealing body 14 . Each signal terminal 26 is electrically connected to a signal pad (not shown) of the semiconductor element 12 .

As shown in FIGS. 3 and 4 , the projecting portion 20 of the second conductor plate 19 has a joint surface 30 in contact with the solder layer 15 and side surfaces 32 extending from the peripheral edge 30 e of the joint surface 30 . The projection 20 has a truncated cone shape, and its side surface 32 is inclined so as to be displaced outward as it moves away from the joint surface 30 . In particular, the protrusion 20 of this embodiment has a truncated pyramid shape, and the side surface 32 of the protrusion 20 includes four flat surfaces 32a, 32b, 32c, and 32d and four corners 34. be

A plurality of guide grooves GG are provided on the side surface 32 of the projecting portion 20 . Although not particularly limited, in this embodiment, four guide grooves GG are provided in the four corners 34 respectively. Each guide groove GG extends along the corner portion 34 from the peripheral edge 30 e of the joint surface 30 to the outer peripheral groove 28 . Thereby, the four guide grooves GG are arranged symmetrically with respect to the joint surface 30 . The number, position and shape of the guide grooves GG are not particularly limited. As another embodiment, the side surface 32 of the protrusion 20 may be provided with at least one guide groove GG. Further, the guide grooves GG are not limited to the corners 34 of the side surfaces 32, and may be provided on the flat surfaces 32a to 32d of the side surfaces 32. FIG. Also, the width and/or depth of the guide groove GG may be constant along its longitudinal direction, or may change continuously or stepwise.

With the above configuration, when manufacturing the semiconductor device 10, it is necessary to solder between the projecting portion 20 of the second conductor plate 19 and the semiconductor element 12. FIG. In this soldering, surplus solder may overflow between the semiconductor element 12 and the projecting portion 20 . In this case, if the surplus solder wets and spreads toward the semiconductor element 12 , there is a risk of causing a short circuit or insulation failure in the semiconductor element 12 . On the other hand, if surplus solder wets and spreads along the side surface 32 of the protruding portion 20, short circuits and poor insulation in the semiconductor element 12 can be avoided. For this reason, in the prior art, the side surfaces 32 of the projecting portion 20 are plated with expensive gold in order to improve the wettability of the solder. However, if the side surface 32 of the protruding portion 20 is widely covered with solder, the adhesion between the side surface 32 and the sealing body 14 is reduced, which may reduce the durability of the semiconductor device 10, for example. be.

On the other hand, in the semiconductor device 10 of this embodiment, the side surface 32 of the projecting portion 20 is provided with the guide groove GG. The cross section of the guide groove GG is sufficiently small, and the melted solder spreads along the guide groove GG. Therefore, surplus solder is guided to the outer peripheral groove 28 through the guide groove GG, and is suppressed from wetting and spreading toward the semiconductor element 12 . In addition, by gathering surplus solder in the guide groove GG, it is avoided that the side surface 32 of the projecting portion 20 is widely covered with solder. As a result, the adhesion between the side surface 32 of the projecting portion 20 and the encapsulant 14 is maintained, and the durability of the semiconductor device 10 is significantly improved. Furthermore, the formation of the guide grooves GG can be performed by, for example, press working, which can be performed at a lower cost than gold plating. Therefore, it is possible to improve the manufacturing quality while suppressing the manufacturing cost of the semiconductor device 10 .

Although specific examples of the technology disclosed in this specification have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as filed. The techniques exemplified in this specification or drawings can achieve a plurality of purposes at the same time, and achieving one of them has technical utility in itself.

10: Semiconductor device 12: Semiconductor element 14: Sealing body 16: First conductor plate 18: Plate-like portion of second conductor plate 19: Second conductor plate 20: Protruding portion of second conductor plate 22: First power terminal 24: Second power terminal 26: Signal terminal 28: Peripheral groove 30: Joint surface of protrusion 32: Side surface of protrusion GG: Guide groove

Claims (1)

a semiconductor element;
a sealing body that seals the semiconductor element;
a conductor member bonded to the semiconductor element via a solder layer inside the sealing body;
with
The conductor member has a plate-like portion and a protruding portion that protrudes from one surface of the plate-like portion,
the protrusion has a joint surface in contact with the solder layer and a side surface extending from a peripheral edge of the joint surface;
The one surface of the plate-like portion is provided with an outer peripheral groove extending along the peripheral edge of the projecting portion,
The side surface of the projecting portion is provided with a guide groove extending from the peripheral edge of the joint surface to the outer peripheral groove,
wherein the protrusion has a shape of a prism or a truncated pyramid, and the side surface of the protrusion has a plurality of flat surfaces and a plurality of corners;
The guide groove is provided along at least one of the plurality of corners ,
semiconductor device.

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