SEMICONDUCTOR PACKAGE AND SEMICONDUCTOR DEVICE

A semiconductor package includes: a semiconductor chip; a plurality of terminals connected to the semiconductor chip; and insulating sealing resin sealing the semiconductor chip and parts of the plurality of terminals, wherein an upper surface of the sealing resin is a flat heat radiation surface, the plurality of terminals respectively protrude from first and second side surfaces of the sealing resin that oppose each other, a distal end portion of each terminal has a substrate bonding surface positioned below a lower surface of the sealing resin, each terminal includes at least two bending portions existing below the heat radiation surface and bent downward, and angles of the bending portions are obtuse angles.

BACKGROUND OF THE INVENTION

Field

The present disclosure relates to a semiconductor package and a semiconductor device.

Background

A semiconductor package for driving a small-capacity domestic/industrial motor has generally adopted a transfer mold type and insertion mounted type external shape from the necessity of radiating heat appropriately for its amount of heat generation. A conventional surface mounted type semiconductor package has formed a U-shaped bending portion having an acute bending angle in a lead terminal (see, e.g., JPH06-085153A (FIG.2)). The U-shaped bending portion of the lead terminal is elastically deformed, to prevent a large stress from acting on a soldered portion of the lead terminal.

SUMMARY

In recent years, a request to reduce the size and the cost of a substrate in a system to be loaded with a semiconductor package for motor driving has become increasingly strong, and an increase in output capability relative to an external size of the package has been required. In such a motion, an increase in output capacity of a surface mounted type semiconductor package conventionally used only for a small-capacity application such as a fan motor and attachment of a heat sink have been attempted. However, in a conventional technique, a U-shaped bending portion of a lead terminal has been arranged to be higher than an upper surface of the package. This has made it impossible to appropriately bring the heat sink into contact with the upper surface of the package because the lead terminal contacts the heat sink and has made it impossible to obtain a good heat radiation property.

In view of the above-described problems, an object of the present disclosure is to provide a semiconductor package and a semiconductor device having a good heat radiation property.

A semiconductor package according to the present disclosure includes: a semiconductor chip; a plurality of terminals connected to the semiconductor chip; and insulating sealing resin sealing the semiconductor chip and parts of the plurality of terminals, wherein an upper surface of the sealing resin is a flat heat radiation surface, the plurality of terminals respectively protrude from first and second side surfaces of the sealing resin that oppose each other, a distal end portion of each terminal has a substrate bonding surface positioned below a lower surface of the sealing resin, each terminal includes at least two bending portions existing below the heat radiation surface and bent downward, and angles of the bending portions are obtuse angles.

In the present disclosure, each terminal includes the at least two bending portions bent downward. Angles of the bending portions are obtuse angles. When the heat sink is attached, the bending portions are respectively elastically deformed when a downward stress is applied to a heat radiation surface of the sealing resin with a distal end portion of each terminal fixed. Accordingly, the terminal can have a sufficient elastic deformation width in a height direction. Therefore, contact between the heat radiation surface of the sealing resin and the heat sink is appropriately maintained. Thus, a good heat radiation property can be obtained.

DESCRIPTION OF EMBODIMENTS

A semiconductor package and a semiconductor device according to the embodiments of the present disclosure will be described with reference to the drawings. The same components will be denoted by the same symbols, and the repeated description thereof may be omitted.

First Embodiment

FIG.1is a plan view illustrating the interior of a semiconductor package according to a first embodiment. The semiconductor package100is a three-phase inverter for motor driving, and is of a surface mounted type. Semiconductor chips1ato1fare each a power semiconductor chip such as an IGBT, a MOSFET, or a Di.

A driving IC chip2ais wire-connected to respective control terminals of the high-side semiconductor chips1ato1c. A driving IC chip2bis wire-connected to respective control terminals of the low-side semiconductor chips1dto1f. The driving IC chips2aand2bare each wire-connected to a plurality of control terminals3. The driving IC chip2adrives the high-side semiconductor chips1ato1c. The driving IC chip2bdrives the low-side semiconductor chips1dto1f.

The semiconductor chips1ato1care mounted on a P-phase main terminal4. The semiconductor chips1dto1fare respectively mounted on U-, V-, and W-phase main terminals4. The semiconductor chips1ato1fare respectively wire-connected to U-, V-, W-, UP-, VP-, and WP-phase main terminals4.

Sealing resin5such as epoxy resin seals the semiconductor chips1ato1f, the driving IC chips2aand2b, a part of each of the control terminals3, and a part of each of the main terminals4with a transfer mold. An external shape of the sealing resin5is rectangular in planar view, and has a first side surface5aand a second side surface5bthat oppose each other, respectively, as long sides. The plurality of control terminals3protrude from the first side surface5a. The plurality of main terminals4protrude from the second side surface5b. The semiconductor chips1ato1fand the driving IC chips2aand2bare connected to the exterior by the control terminals3and the main terminals4that protrude from the sealing resin5. Each of the main terminals4performs output of a current to a motor or connection to a high voltage power source. Each of the control terminals3inputs a motor driving signal, inputs a protection signal, outputs an error signal, and supplies an IC driving power source, for example.

FIG.2is a side view illustrating the semiconductor package according to the first embodiment. An upper surface of the sealing resin5is a flat heat radiation surface. Respective distal end portions of the main terminal4and the control terminal3have substrate bonding surfaces6positioned below a lower surface of the sealing resin5. The respective substrate bonding surfaces6of the plurality of main terminals4and the plurality of control terminals3are positioned at the same height.

The main terminal4and the control terminal3exist below a heat radiation surface5c. Each of the main terminal4and the control terminal3includes at least two bending portions7aand7bbent downward. Respective angles θ1and θ2of the bending portions7aand7bare obtuse angles. Each of the substrate bonding surfaces6of the semiconductor package is bonded to an electrode of a substrate101with a bonding material8such as a solder interposed therebetween.

FIG.3is a side view illustrating a semiconductor device according to the first embodiment. A heat sink102is attached to the heat radiation surface5cof the semiconductor package100. A heat radiation grease10or an insulating heat radiation resin sheet, for example, is provided as a heat transfer member between the heat radiation surface5cand the heat sink102.

The heat sink102is fixed to the substrate101with a screw9. An external shape of the sealing resin5is pressed downward by tightening the screw9. Thus, the main terminal4and the control terminal3in the semiconductor package100are elastically deformed. The heat radiation surface5cof the sealing resin5is pressed against the heat sink102with respective repulsive forces of the main terminal4and the control terminal3elastically deformed.

A spacer11having an appropriate height is inserted between the heat sink102and the substrate101such that the lower surface of the sealing resin5does not contact the substrate101after the screw9is tightened. Although the spacer11is provided in a portion of the screw9, the present disclosure is not limited to this. As long as the substrate101and the heat sink102can be held with an appropriate spacing, the screw9may be provided in another location.

In a conventional technique, the number of bending portions of each of terminals is only one. Only the one bending portion is elastically deformed. Accordingly, an elastic deformation width in a height direction is small. On the other hand, in the present embodiment, each of the main terminal4and the control terminal3includes the at least two bending portions7aand7bbent downward. The respective angles θ1and θ2of the bending portions7aand7bare obtuse angles. When the heat sink102is attached, the two bending portions7aand7bare respectively elastically deformed when a downward stress is applied to the heat radiation surface5cof the sealing resin5with the distal end portion of each of the terminals fixed. Accordingly, the main terminal4and the control terminal3can have a sufficient elastic deformation width in a height direction. Therefore, contact between the heat radiation surface5cof the sealing resin5and the heat sink102is appropriately maintained. Thus, a good heat radiation property can be obtained.

Each of the main terminal4and the control terminal3exists below the heat radiation surface5cand does not have a portion above the heat radiation surface5c. Accordingly, a part of each of the main terminal4and the control terminal3does not contact the heat sink102. Thus, the heat sink102can be appropriately brought into contact with the heat radiation surface5c.

In the conventional technique, a direction in which the bending portion is deformed is limited to a transverse direction. Accordingly, elasticity in a longitudinal direction is not exerted, whereby a height cannot be adjusted. On the other hand, in the present embodiment, the at least two bending portions7aand7bare elastically deformed so that elasticity in a longitudinal direction is exerted, whereby a height can be adjusted. Accordingly, semiconductor packages respectively having different heights can be mounted on the same heat sink102.

FIG.4is a side view illustrating a semiconductor device according to a comparative example. A heat sink of a large size is required to radiate heat of a surface mounted type semiconductor package the amount of heat radiation of which has increased by increasing its output capacity. In a conventional DIP-shaped semiconductor device, an external shape of sealing resin has been screwed. However, the weight of the heat sink is supported by a soldered portion of a terminal, resulting in a problem that the soldered portion deteriorates by vibration at the time of a system operation. In the comparative example, a heat sink102is fixed to a substrate101with a screw9. If the semiconductor package is mounted at a normal height, a spacing between an upper surface of the substrate101and a lower surface of sealing resin5is as small as approximately 0.5 mm, and both the surfaces contact each other when a screw is tightened. In the case of a surface mounted type, the semiconductor package is generally mounted such that the lower surface of the sealing resin floats from the substrate so that a stress is not transmitted to an external shape of the sealing resin at the time of occurrence of bending of the substrate, for example. On the other hand, in the present embodiment, the main terminal4and the control terminal3respectively have the sufficient elastic deformation widths in the height direction, as described above. Accordingly, the semiconductor package100can be mounted such that a height of the heat radiation surface5cand a height of the lower surface of the sealing resin5from the substrate101increase. Even when the heat sink102is fixed to the substrate101with the screw9, the lower surface of the sealing resin5is maintained in a state floating from the substrate101. Accordingly, a stress to the semiconductor package100from the substrate101can be relieved.

FIG.5is a side view illustrating a modification of the semiconductor device according to the first embodiment. Not only a semiconductor package100according to the present embodiment but also another device103requiring heat radiation such as a diode module may be mounted on a substrate101to share a heat sink102. The other device103is fixed to the heat sink102with a screw9. In a state where the heat sink102has not been attached yet, a heat radiation surface5cof the semiconductor package100is made higher than a heat radiation surface of the other device103. As a result, screwing and a spacer for the semiconductor package100are not required, thereby making it possible to reduce a mounting cost and a member cost.

Second Embodiment

FIG.6is a side view illustrating a semiconductor device according to a second embodiment. A root portion of each of a main terminal4and a control terminal3that protrude in a transverse direction from a side surface of sealing resin5is provided with a folded portion12. The folded portion12has a shape such as a U, S, V, or concave shape folded in a longitudinal direction.

In the first embodiment, when an attempt to ensure the height of the semiconductor package is made, the main terminal4and the control terminal3transversely protrude. Accordingly, a mounting area on the substrate101increases. On the other hand, in the present embodiment, the main terminal4and the control terminal3are respectively provided with the folded portions12. Even if the folded portions12are provided, an amount of transverse protrusion of each of the main terminal4and the control terminal3is small. Accordingly, a mounting area hardly increases.

When a heat sink102is attached, the folded portion12is elastically deformed when a downward stress is applied to a heat radiation surface5cof sealing resin5with a distal end portion of each of the terminals fixed. As a result, a mounting area on a substrate101is reduced, whereby an adjustment margin of a mounting height can be enlarged. Even in a case where an external surface of the sealing resin5is not horizontal, for example, a case where the substrate101is deflected, the heat sink102can be appropriately brought into contact with the heat radiation surface5c. Other components and effects are similar to those in the first embodiment.

If the folded portion12has a V shape, an angle formed between two inclined portions constituting the V shape is preferably 30 degrees or more. When the angle is thus widened, the main terminal4and the control terminal3are easily elastically deformed.

FIGS.7and8are side views each illustrating a modification 1 of the semiconductor device according to the second embodiment. A folded portion12is provided in a downward extending portion of each of a main terminal4and a control terminal3, and has a shape such as a U, S, V, or concave shape folded in a transverse direction. As a result, a semiconductor package can be mounted with its height kept. A stress to be applied when a heat sink102is attached is not easily applied in a shear direction of soldering (in the transverse direction in the figure). Accordingly, the reliability of a soldered portion is improved. A mounting area can be further reduced.

As illustrated inFIG.8, two semiconductor packages100can also be arranged side by side and bonded to a substrate101to share a heat sink102. When the heat sink102is pressed against respective heat radiation surfaces5cof the two semiconductor packages100and is fixed, respective folded portions12of a main terminal4and a control terminal3in each of the two semiconductor packages100are elastically deformed. Thus, the respective heights of the heat radiation surfaces5cof the two semiconductor packages100are made uniform. Accordingly, the heat radiation surfaces5cof the two semiconductor packages100need not be uniform in height when bonded to the substrate101. Even if a spacing between the substrate101and the heat sink102is not uniform, an amount of elastic deformation of the folded portion12of each of the terminals is adjusted. Thus, the heat sink102can be appropriately brought into contact with the respective heat radiation surfaces5cof the two semiconductor packages100.

FIG.9is a side view illustrating a modification 2 of the semiconductor device according to the second embodiment. An entire shape of each of a main terminal4and a control terminal3is an S-shaped folded portion12.FIG.10is a side view illustrating a modification 3 of the semiconductor device according to the second embodiment. An entire shape of each of a main terminal4and a control terminal3is a transverse U-shaped folded portion12. If respective shapes of the main terminal4and the control terminal3are thus simple, the main terminal4and the control terminal3are easily processed.

Third Embodiment

FIG.11is a top view illustrating a semiconductor package according to a third embodiment. The width of a main terminal4protruding from a second side surface5bis larger than the width of a control terminal3protruding from a first side surface5a. Therefore, the control terminal3has a low modulus of elasticity, and is elastically deformed.

FIG.12is a side view illustrating a semiconductor device according to the third embodiment. Both ends of a substrate101is attached to a heat sink102with a spacer11interposed therebetween. At an attachment position, a spacing between the substrate101and the heat sink102is ensured by the spacer11. On the other hand, the substrate101is deflected, whereby the spacing between the substrate101and the heat sink102is narrow in a central portion of the substrate101. A mounting direction of the semiconductor package is set such that the control terminal3is located on the narrower side of the spacing. Therefore, the spacing between the substrate101and the heat sink102on the control terminal3side is narrower than the spacing between the substrate101and the heat sink102on the main terminal4side.

Generally, the substrate101is deflected and is not flat. Thus, the substrate101and an attachment plane of the heat sink102may not be parallel to each other. When the deflection of the substrate101is large, contact between a heat radiation surface5cof the semiconductor package and the heat sink102may be unable to be approximately maintained. A direction in which the substrate101is easily deflected is previously grasped, to set the mounting direction of the semiconductor package such that the control terminal3is oriented toward the narrower side of the spacing between the substrate101and the heat sink102. As a result, the main terminal4and the control terminal3are elastically deformed to correspond to a difference in the spacing between the substrate101and the heat sink102so that appropriate contact between the heat radiation surfaces5cof the semiconductor package and the heat sink102can be maintained.

A material for the main terminal4and a material for the control terminal3may be made to differ in modulus of elasticity. For example, the main terminal4and the control terminal3are respectively made of Fe (iron) and Cu (copper). In this case, the modulus of elasticity of the main terminal4is larger than that of the control terminal3The materials for the main terminal4and the control terminal3are not limited to such a combination, but may be respectively materials having different moduli of elasticity. The mounting direction of the semiconductor package is set such that the terminal having the lower modulus of elasticity is oriented toward the narrower side of the spacing between the substrate101and the heat sink102. As a result, even in a case where a surface of sealing resin5is not horizontal, for example, a case where the substrate101is deflected, appropriate contact between the heat radiation surface5cof the semiconductor package and the heat sink102can be maintained.

An external shape of the sealing resin5is not firmly fixed with a screw or the like. Accordingly, the external shape of the sealing resin5resonates when vibration has occurred during a system operation, whereby there may occur defects such as respective damages to the main terminal4and the control terminal3and detachment of a soldered portion. The control terminal3and the main terminal4may be respectively made to have different shapes. As a result, respective resonance frequencies of the terminals differ from each other. Accordingly, the defects can be prevented by suppressing overall resonance vibration.

Fourth Embodiment

FIG.13is a side view illustrating a semiconductor device according to a fourth embodiment. When a heat sink102is attached, a main terminal4and a control terminal3are elastically deformed to come closer to a surface of the heat sink102. In the present embodiment, the heat sink102is provided with a groove13in a portion opposing each of the main terminal4and the control terminal3of a semiconductor package100. As a result, a specific insulation distance can be ensured between each of the control terminal3and the main terminal4elastically deformed and the heat sink102made of a metal.

The semiconductor chips1ato1fare not limited to semiconductor chips formed of silicon, but instead may be formed of a wide-bandgap semiconductor having a bandgap wider than that of silicon. The wide-bandgap semiconductor is, for example, a silicon carbide, a gallium-nitride-based material, or diamond. A semiconductor chip formed of such a wide-bandgap semiconductor has a high voltage resistance and a high allowable current density, and thus can be miniaturized. The use of such a miniaturized semiconductor chip enables the miniaturization and high integration of the semiconductor device in which the semiconductor chip is incorporated. Further, since the semiconductor chip has a high heat resistance, a radiation fin of a heatsink can be miniaturized and a water-cooled part can be air-cooled, which leads to further miniaturization of the semiconductor device. Further, since the semiconductor chip has a low power loss and a high efficiency, a highly efficient semiconductor device can be achieved.

The entire disclosure of Japanese Patent Application No. 2021-198300, filed on Dec. 7, 2021 including specification, claims, drawings and summary, on which the convention priority of the present application is based, is incorporated herein by reference in its entirety.