阅读说明：本技术 半导体装置 (Semiconductor device with a plurality of semiconductor chips ) 是由 梅田宗一郎 久德淳志 于 2019-12-16 设计创作，主要内容包括：本发明的半导体装置100包括：电路基板10；具有主电极23的半导体元件20；金属框30；以及配置在金属框30与主电极23之间的平板状的金属板40,其中,金属板40以及导电性接合材料52、53构成了用于缓和施加于金属框40与半导体元件20之间的金属板40处以及导电性接合材料52、53处的应力的应力缓和结构,该应力缓和结构的具体结构为：金属板40的厚度比金属框30的厚度薄,且在金属板40上的与主电极23相对应的位置上形成有至少一个凸部41。根据本发明的半导体装置100,即使在使用比较厚的金属框的情况下,也能够缓和施加于半导体元件与金属框之间的导电性接合材料处的应力。(The semiconductor device 100 of the present invention includes: a circuit board (10); a semiconductor element 20 having a main electrode 23; a metal frame 30; and a flat plate-like metal plate 40 disposed between the metal frame 30 and the main electrode 23, wherein the metal plate 40 and the conductive bonding materials 52 and 53 constitute a stress relaxation structure for relaxing stress applied to the metal plate 40 and the conductive bonding materials 52 and 53 between the metal frame 40 and the semiconductor element 20, and the stress relaxation structure has a specific structure of: the metal plate 40 is thinner than the metal frame 30, and at least one projection 41 is formed on the metal plate 40 at a position corresponding to the main electrode 23. According to the semiconductor device 100 of the present invention, even when a relatively thick metal frame is used, stress applied to the conductive bonding material between the semiconductor element and the metal frame can be relaxed.)

1. A semiconductor device, comprising:

a circuit substrate;

a semiconductor element mounted on the circuit board, a main electrode of the semiconductor element being located on a surface opposite to a side facing the circuit board;

a metal frame disposed on the main electrode side of the semiconductor element; and

a flat plate-like metal plate disposed between the metal frame and the main electrode,

wherein a conductive bonding material is disposed between the metal plate and the main electrode and between the metal plate and the metal frame,

the metal plate and the conductive bonding material constitute a stress relaxation structure for relaxing stress applied to the metal plate and the conductive bonding material between the metal frame and the semiconductor element,

the stress relaxation structure has the specific structure that: the metal plate has a thickness smaller than that of the metal frame, and at least one protrusion is formed on the metal plate at a position corresponding to the main electrode.

2. The semiconductor device according to claim 1, wherein:

wherein the metal plate in the stress relaxing structure is formed of an elastic member.

3. The semiconductor device according to claim 1 or 2, wherein:

wherein the convex portion in the stress relaxing structure is formed on the surface of the metal plate on the main electrode side.

4. The semiconductor device according to claim 1 or 2, wherein:

wherein, in the stress relaxing structure, the convex portion is formed on both surfaces of the metal plate.

5. The semiconductor device according to any one of claims 1 to 4, wherein:

wherein the main electrode has a plurality of regions,

in the stress relaxing structure, the convex portion is formed on the metal plate at a position corresponding to each of the plurality of regions of the main electrode.

6. The semiconductor device according to claim 5, wherein:

wherein the plurality of regions are independent of each other.

7. The semiconductor device according to any one of claims 1 to 6, wherein:

wherein the semiconductor element further comprises a sub-electrode provided at a position apart from the main electrode on a surface opposite to the circuit substrate,

the metal plate is provided with a notch so as to avoid the sub-electrode.

8. The semiconductor device according to any one of claims 1 to 7, wherein:

wherein a convex portion is formed on the metal frame at a position corresponding to the metal plate.

9. The semiconductor device according to any one of claims 1 to 8, wherein:

wherein the metal plate is symmetrically arranged with respect to the center of the main electrode.

10. The semiconductor device according to any one of claims 1 to 9, wherein:

wherein a source electrode as the main electrode and a gate electrode as a sub electrode are formed on a surface of the semiconductor element on the opposite side to the side facing the circuit substrate, and a drain electrode is formed on the semiconductor element on the side facing the circuit substrate.

11. The semiconductor device according to any one of claims 1 to 9, wherein:

wherein a source electrode and a drain electrode as the main electrodes and a gate electrode as a sub electrode are formed on a surface of the semiconductor element on the metal frame side.

12. The semiconductor device according to claim 10 or 11, wherein:

the circuit board is provided with a plurality of semiconductor elements, and the metal plate is disposed between the main electrodes of the semiconductor elements and the metal frame.

13. The semiconductor device according to any one of claims 1 to 12, wherein:

wherein, the circuit substrate is a ceramic substrate.

14. The semiconductor device according to any one of claims 1 to 13, wherein:

wherein an area of the metal plate is narrower than an area of the semiconductor element in plan view.

15. The semiconductor device according to any one of claims 1 to 14, further comprising:

and a pin terminal which penetrates the metal frame, one end of which protrudes to the outside, and the other end of which is connected to the wiring pattern of the circuit board.

Technical Field

The present invention relates to a semiconductor device.

Background

Conventionally, a semiconductor device is known in which a semiconductor element mounted on a circuit board and a metal frame such as a lead frame are bonded to each other using a conductive bonding material such as solder (for example, see a conventional semiconductor device 900 in patent document 1).

Fig. 16 is a diagram illustrating a conventional semiconductor device 900.

As shown in fig. 16, the conventional semiconductor device 900 is a device in which a convex portion 941 is provided on a terminal 911(913) (of a metal frame) facing a semiconductor element 995, and a conductive bonding material (conductive adhesive, solder, or the like) 975 is disposed between the semiconductor element 995 and the terminal 911 (913). In the figure, reference numeral 999 denotes a jig.

According to the conventional semiconductor device 900, since the convex portions 941 are provided on the terminals 911 and 913 (of the metal frame) facing the semiconductor element 995, the distance between the semiconductor element 995 and the terminals 911 is kept at a predetermined value or more, and the thickness of the conductive bonding material disposed between the region where no convex portion is formed and the semiconductor element 995 is kept at a predetermined value or more, whereby stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element and the metal frame can be relaxed.

Prior art documents

[ patent document 1 ] Japanese patent No. 6346717

However, in recent years, in particular, in semiconductor devices used for electric power and the like, a relatively thick metal frame is used for flowing a large current, but with the recent demand for downsizing of electric equipment, the downsizing of the semiconductor device (and semiconductor element) has been advanced, and even if a convex portion of the conventional semiconductor device 900 is formed by processing a relatively thick metal frame, a convex portion corresponding to a fine main electrode of the semiconductor element (after the downsizing) is not easily formed, and it is difficult to relax stress (for example, thermal stress) acting on a conductive bonding material between the semiconductor element and the metal frame by maintaining the thickness of the conductive bonding material at a certain value or more by the convex portion.

In view of the above-described problems, an object of the present invention is to provide a semiconductor device capable of relaxing stress (for example, thermal stress) acting on a conductive bonding material between a semiconductor element and a metal frame even when the metal frame is relatively thick.

Disclosure of Invention

The semiconductor device according to the present invention includes: a circuit substrate; a semiconductor element mounted on the circuit board, a main electrode of the semiconductor element being located on a surface opposite to a side facing the circuit board; a metal frame disposed on the main electrode side of the semiconductor element; and a flat plate-like metal plate disposed between the metal frame and the main electrode, wherein conductive bonding materials are disposed between the metal plate and the main electrode and between the metal plate and the metal frame, and the metal plate and the conductive bonding materials constitute a stress relaxation structure for relaxing stress applied to the metal plate between the metal frame and the semiconductor element and stress applied to the conductive bonding materials, and the stress relaxation structure has a specific structure of: the metal plate has a thickness smaller than that of the metal frame, and at least one protrusion is formed on the metal plate at a position corresponding to the main electrode.

In the present specification, the "metal frame" refers to a flat plate (e.g., a lead frame) made of metal itself or a flat plate (e.g., a clip lead (connector)) formed by punching or bending the flat plate made of metal. The "flat plate-like metal plate" is a metal plate that is not bent greatly, and strictly speaking, even if there are some irregularities, it is only necessary to have a flat plate-like shape as a whole. In other words, the metal plate after press working corresponds to a "flat plate-like metal plate", but the metal plate after bending does not correspond to a "flat plate-like metal plate".

In the semiconductor device of the present invention, in the stress relaxing structure, the metal plate is formed of an elastic member.

In the semiconductor device of the present invention, in the stress relaxing structure, the convex portion is formed on the surface of the metal plate on the main electrode side.

In the semiconductor device of the present invention, the stress relaxation structure may be configured such that the convex portion is formed on both surfaces of the metal plate.

In the semiconductor device of the present invention, the main electrode has a plurality of regions, and in the stress relaxation structure, the projections are formed on the metal plate at positions corresponding to the plurality of regions of the main electrode, respectively.

In the semiconductor device of the present invention, the plurality of regions are independent of each other.

In the present specification, "independent" means that the conductive bonding materials 52 are formed independently of each other to such an extent that they do not flow into another adjacent region, for example, and this means not only a case where they are completely separated but also a case where a plurality of regions are nominally connected by a very fine wiring pattern is included in the category of "independent".

In the semiconductor device according to the present invention, the semiconductor element further includes a sub-electrode provided at a position apart from the main electrode on a surface opposite to the side facing the circuit board, and the metal plate is provided with a notch so as to avoid the sub-electrode.

In the semiconductor device of the present invention, a convex portion is formed at a position corresponding to the metal plate on the metal frame.

In the semiconductor device of the present invention, the metal plate is disposed symmetrically with respect to the center of the main electrode.

In the semiconductor device of the present invention, a source electrode as the main electrode and a gate electrode as a sub-electrode are formed on a surface of the semiconductor element on the opposite side to the side facing the circuit substrate, and a drain electrode is formed on the semiconductor element on the side facing the circuit substrate.

In the semiconductor device of the present invention, a source electrode and a drain electrode as the main electrodes and a gate electrode as a sub electrode are formed on a surface of the semiconductor element on the metal frame side.

In the semiconductor device according to the present invention, the plurality of semiconductor elements are mounted on the circuit board, and the metal plate is disposed between the main electrodes of the semiconductor elements and the metal frame.

In the semiconductor device of the present invention, the circuit board is a ceramic board.

In the semiconductor device of the present invention, the area of the metal plate is narrower than the area of the semiconductor element in plan view.

In the semiconductor device of the present invention, further comprising: and a pin terminal which penetrates the metal frame, one end of which protrudes to the outside, and the other end of which is connected to the wiring pattern of the circuit board.

Effects of the invention

According to the semiconductor device of the present invention, since the stress relaxation structure has a structure in which at least one projection is formed at a position on the metal plate corresponding to the main electrode, a space having at least a height of the projection can be secured between the metal plate and the main electrode by the projection, and a space between the region where the projection is not formed and the main electrode can be maintained at a certain amount or more. In this way, the thickness of the conductive bonding material disposed between the region where the projection is not formed and the main electrode can be kept at a predetermined value or more, and stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element and the metal frame can be alleviated.

In the semiconductor device according to the present invention, the metal plate has a thickness smaller than that of the metal frame in the stress relaxation structure, and at least one convex portion is formed at a position corresponding to the main electrode on the metal plate. In this way, the projection corresponding to the fine main electrode of the semiconductor element can be formed using a metal plate which is thinner than the metal frame and which can be easily subjected to microfabrication. Particularly when the metal plate is thin to such an extent that the convex portion can be formed by press working, the convex portion can be easily formed by press working the metal plate.

In general, when a high withstand voltage is ensured, it is necessary to form the conductive bonding material to be thick in order to ensure an insulation distance (in order to prevent a short circuit between the metal frame and the circuit board), but when no convex portion is formed on the metal frame or a convex portion that is much shorter than a gap between the metal frame and the main electrode is formed and the conductive bonding material is filled between the metal frame and the main electrode, the conductive bonding material may be damaged when the metal frame is placed on the conductive bonding material during the manufacturing process, and it is difficult to improve the reliability of the semiconductor device.

In contrast, according to the semiconductor device of the present invention, since the flat plate-like metal plate is disposed between the metal frame and the main electrode, the space between the metal frame and the main electrode may not be entirely filled with the conductive bonding material. Thus, in the manufacturing process, the conductive bonding material can be prevented from being damaged when the metal frame is disposed on the conductive bonding material, and the reliability of the semiconductor device is not easily lowered. Further, since the stress relaxation structure has a structure in which at least one projection is formed at a position on the metal plate corresponding to the main electrode, even when the distance between the metal frame and the main electrode is increased, the metal plate and the main electrode can be easily maintained at a predetermined distance. Thus, the conductive bonding material between the metal plate and the metal frame does not need to be excessively thick, and the conductive bonding material is less likely to be crushed, so that the reliability of the semiconductor device is less likely to be lowered.

In addition, according to the semiconductor device of the present invention, since the stress relaxation structure has a structure in which the thickness of the metal plate is smaller than the thickness of the metal frame, the metal plate itself can be deformed by stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element and the metal frame and absorb the stress. In this way, stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element and the metal frame can be further relaxed. Further, the stress relaxation structure has a structure in which the metal plate has a thickness smaller than that of the metal frame and at least one projection is formed at a position corresponding to the main electrode on the metal plate, so that the thickness of the conductive bonding material disposed between the region where no projection is formed and the main electrode can be maintained at a constant value or more. In addition to the stress absorption by the deformation of the metal plate itself, the stress can be further absorbed by the conductive bonding material disposed between the region where the projection is not formed and the main electrode. In this way, stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element and the metal frame can be further relaxed.

Further, according to the semiconductor device of the present invention, since the stress relaxation structure has a structure in which at least one convex portion is formed at a position corresponding to the main electrode on the metal plate, the electrode and the metal plate can be reliably joined by making the starting point of solder wet spread with the conductive joining material intensively joined around the position of the convex portion of the metal plate, and by providing the cut in the metal plate so as to avoid the sub-electrode, wet spread of solder to the sub-electrode can be suppressed, and the possibility of occurrence of short circuit between the main electrode and the sub-electrode can be reduced.

Drawings

Fig. 1 is a diagram illustrating a semiconductor device 100 according to an embodiment.

Fig. 2 is a diagram for explaining a conductive bonding material between a metal frame and a semiconductor element and stress applied to a metal plate.

Fig. 3 is an enlarged plan view of a main portion of a semiconductor device 100a according to a second embodiment.

Fig. 4 is a peripheral exploded view of the semiconductor element 20 according to the second embodiment.

Fig. 5 is a diagram for explaining a semiconductor device 100b according to a modification.

Fig. 6 is a circuit diagram of a semiconductor device 100b according to a modification.

Fig. 7 is an enlarged cross-sectional view of a main portion of a semiconductor device 100b according to a modification.

Fig. 8 is a diagram for explaining a semiconductor device 100c according to the third embodiment.

Fig. 9 is an enlarged cross-sectional view of a main portion of a semiconductor device 100c according to a third embodiment.

Fig. 10 is a diagram for explaining a semiconductor device 100d according to the fourth embodiment.

Fig. 11 is a diagram for explaining a semiconductor device 100e according to the fifth embodiment.

Fig. 12 is a diagram for explaining semiconductor devices 100f to 100h according to the sixth to eighth embodiments.

Fig. 13 is a diagram for explaining semiconductor devices 100i to 100k according to ninth to eleventh embodiments.

Fig. 14 is a schematic sectional view of a semiconductor device 100l according to a twelfth embodiment.

Fig. 15 is a diagram illustrating a semiconductor device 100m according to a thirteenth embodiment.

Fig. 16 is a diagram illustrating a conventional semiconductor device 900.

Detailed Description

Hereinafter, a semiconductor device according to the present invention will be described with reference to embodiments shown in the drawings. In addition, each drawing is a schematic diagram, and does not necessarily reflect an actual size strictly.

[ first embodiment ] to provide a toner

1. Structure of semiconductor device 100 according to the first embodiment

Fig. 1 is a diagram illustrating a semiconductor device 100 according to an embodiment. Fig. 1(a) is a schematic sectional view of the semiconductor device 100, and fig. 1(B) is an enlarged plan view of a main portion of the semiconductor device 100.

The semiconductor device 100 is covered with an insulating mold resin 60 including the circuit board 10, the semiconductor element 20, the metal frame 30, and the metal plate 40 (see fig. 1 a). The semiconductor device 100 is a power semiconductor device used for power control and the like. The semiconductor device 100 is also referred to as a semiconductor module.

The circuit board 10 is a substrate in which a pattern wiring layer 12 is formed on one surface of an insulating substrate 11. The pattern wiring layer 12 has a semiconductor element mounting portion 14 on which the semiconductor element 20 is mounted, and an electrode portion 15 connected to a source electrode 23 (front surface electrode) of the semiconductor element 20 via a metal frame 30, and the pattern wiring layer 12 is connected to a terminal not shown for external connection.

The circuit board 10 is preferably a ceramic substrate having a coefficient of linear expansion close to that of the semiconductor element 20, and in the first embodiment, a DCB substrate (Direct Copper Bonding substrate) in which the pattern wiring layer 12 is formed on the front surface of the alumina ceramic substrate and the heat dissipation plate 13 is formed on the back surface is used as the circuit board 10, or a substrate such as a printed circuit board may be used. In this case, a heat dissipating member (for example, a heat dissipating member formed of a plate-like metal layer such as copper, iron, or aluminum) is preferably provided on the rear surface.

The heat dissipation plate 13 and the heat dissipation member on the back surface of the DCB substrate are electrically insulated from the semiconductor element 20, but may be connected to a ground electrode of a device using the semiconductor device 100.

The semiconductor element 20 is disposed on the pattern wiring layer 12 (semiconductor element mounting portion 14) of the circuit board 10 and bonded thereto by a conductive bonding material 51 (e.g., solder). The semiconductor element 20 is a power semiconductor element.

The semiconductor element 20 includes: the semiconductor device includes a base 21, a drain electrode 22 formed on a side of the base 21 facing the circuit board 10, a source electrode 23 as a main electrode formed on a surface of the base opposite to the side facing the circuit board 10, and a gate electrode 24 as a sub-electrode. The substrate 21 is composed of a substrate of a suitable material (e.g., silicon carbide, gallium nitride, etc.).

The metal frame 30 is disposed on the source electrode 23 side of the semiconductor element 20 via a conductive bonding material 52, a metal plate 40 described later, and a conductive bonding material 53. Therefore, a large current can be conducted to a path through which the main current flows without blocking the main current. The metal frame 30 is (a connector of) a clip lead formed by punching, bending, or the like a flat metal plate. One end of the metal frame 30 is electrically connected to the source electrode 23, and the other end is electrically connected to the electrode portion 15 of the circuit board 10 via the conductive bonding material 55.

Further, although the gate electrode 24 is bonded to the wiring member 32 via the conductive bonding material 54 (e.g., solder) (see fig. 1), the current flowing through the gate electrode 24 is much smaller than the current flowing between the source electrode 23 and the drain electrode 22, and therefore, the thickness (cross-sectional area) of the wiring member 32 may be a clip wire or a lead wire as the wiring member 32.

The metal plate 40 is a flat plate-like member disposed between the metal frame 30 and the source electrode 23. The metal plate 40 is disposed at a position corresponding to the source electrode 23 (a position where the metal plate 40 and the source electrode 23 overlap when the semiconductor device 100 is viewed from a direction perpendicular to the circuit board 10).

Conductive bonding materials 52 and 53 (e.g., solder) are disposed between the metal plate 40 and the source electrode 23 and between the metal plate 40 and the metal frame 30. The metal plate 40 and the conductive bonding materials 52 and 53 constitute a stress relaxation structure, which will be described later in detail.

The metal plate 40 is composed of an elastic member. The thickness of the metal plate 40 is thinner than that of the metal frame 30. Further, a plurality of (6) projections 41 are formed on the metal plate 40 on the source electrode 23 side at positions corresponding to the source electrode 23.

The metal plate 40 has a rectangular shape in plan view, and has one convex portion 41 formed near each corner of the rectangle, and two convex portions 41 formed at an appropriate interval (with good balance) in the central portion. In addition, if 3 or more projections 41 are formed, the metal plate 40 can be stably arranged on the semiconductor element 20 when the metal plate 40 is placed on the semiconductor element 20 with the projections 41 facing downward in the manufacturing process.

As described above, in the first embodiment, by forming the convex portion on the metal plate 40 thinner than the metal frame 30 instead of the thick metal frame 30 in which the small convex portion is difficult to form, even if the convex portion is not formed on the metal frame 30, the interval between the semiconductor element 20 and the metal frame 40 can be maintained at a certain value or more.

When the thickness of the metal frame 30 is t2, the thickness of the region of the metal plate 40 where the convex portion 41 is formed is t12, and the thickness of the region of the metal plate 40 where the convex portion 41 is not formed is t1, t1< t2 and t12< t2 are satisfied. When the height of the projection is t11 (t 12-t1), t11< t1, for example, t11<0, is satisfied. 5 × t 1.

The area of the metal plate 40 is narrower than the area of the semiconductor element, and further narrower than the area of the region where the active electrode 23 is formed, when viewed in plan.

The metal plate 40 is symmetrical with respect to the center of the source electrode 23, i.e., does not bend and maintains a flat plate-like configuration. The convex portions 41 are also provided at positions symmetrical with respect to the vertical bisector of each side of the metal plate 40.

2. Stress relaxation structure

Before describing the stress relaxation structure, the stress applied to the metal plate 40 and the conductive bonding materials 52 and 53 between the metal frame 30 and the semiconductor element 20 will be described.

Fig. 2 is a schematic diagram for explaining a conductive bonding material between a metal frame and a semiconductor element and stress applied to a metal plate.

In an electric apparatus in which the semiconductor device 100 is mounted, the ambient temperature may increase depending on the usage environment. In particular, in an electronic device using a large current assumed by the present invention, surrounding members are also likely to generate heat, and a high-temperature environment is likely to be formed.

In this case, stress is applied in a direction in which the circuit board 10 warps (see fig. 2). In this case, in the semiconductor device 100, since the difference in the linear expansion coefficient between the semiconductor element 20 (silicon carbide, etc.) and the metal frame 30 (copper) is large, the stress received by the conductive bonding materials 52 and 53 and the metal plate 40 between the semiconductor element 20 and the metal frame 30 is the largest, and such stress is likely to cause cracking of the conductive bonding material or peeling between the conductive bonding material and the metal frame (or the semiconductor element).

In order to alleviate such stress, in the semiconductor device 100 according to the first embodiment, the metal plate 40 and the conductive bonding materials 52 and 53 constitute a stress alleviating structure that alleviates stress applied to the metal plate 40 and the conductive bonding materials 52 and 53 between the metal frame 30 and the semiconductor element 20.

The stress relaxation structure has the structure: the metal plate 40 is thinner than the metal frame 30, and at least one (6) convex portions are formed on the metal plate 40 at positions corresponding to the source electrodes 23, the convex portions being formed on the surface of the metal plate 40 on the source electrode 23 side. With this configuration, the convex portion 41 can secure a space having at least the height of one convex portion 41, and the thickness of the conductive bonding material 52 can be maintained at a constant value or more. Further, since the distance between the metal frame 30 and the semiconductor element 20 can be made relatively wide, even if the conductive bonding material sandwiching the metal plate 40 is relatively thick, the conductive bonding material is less likely to receive excessive pressure, and stress of the conductive bonding material is surely relaxed in a highly reliable state.

In addition, since the metal plate 40 in the stress relaxing structure is formed of an elastic member, the metal plate 40 itself can be deformed to relax the stress.

3. Effects of the semiconductor device 100 according to the first embodiment

According to the semiconductor device 100 of the first embodiment, since the stress relaxation structure has a structure in which at least one convex portion 41 is formed at a position of the metal plate 40 corresponding to the main electrode (source electrode 23), the thickness of the conductive bonding material 52 disposed between the region of the metal plate 40 where the convex portion 41 is not formed and the source electrode 23 can be maintained at a constant value or more by ensuring a space at least corresponding to the height of the convex portion 41 between the metal plate 40 and the source electrode 23 by the convex portion 41, and thus, the stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 and the metal plate 40 between the semiconductor element 20 and the metal frame 30 can be relaxed.

In addition, according to the semiconductor device 100 of the first embodiment, since the stress relaxation structure has a structure in which the thickness of the metal plate 40 is smaller than the thickness of the metal frame 30 and at least one convex portion 41 is formed at a position on the metal plate 40 corresponding to the source electrode 23, it is not necessary to form the convex portion by processing the metal frame 30 having a relatively large thickness. In this way, the convex portion 41 corresponding to the minute source electrode 23 of the semiconductor element 20 can be formed using the metal plate 40 which is thinner than the metal frame 30 and can be easily subjected to microfabrication. In particular, in the case where the metal plate 40 is thin to such an extent that the convex portion 41 can be formed by press working, the convex portion 41 can be easily formed by press-pressing the metal plate 40.

In general, when a high withstand voltage is to be ensured, it is necessary to form the conductive bonding material to be thick in order to ensure an insulation distance (in order to prevent a short circuit between the metal frame and the circuit board), but when no convex portion is formed on the metal frame or a convex portion that is much shorter than the distance between the metal frame and the main electrode is formed and the conductive bonding material is filled between the metal frame and the main electrode (see the distance t3 in fig. 1), there is a possibility that the conductive bonding material is damaged when the metal frame is placed on the conductive bonding material during the manufacturing process, and it is difficult to improve the reliability of the semiconductor device.

In contrast, according to the semiconductor device 100 of the first embodiment, since the flat plate-like metal plate 40 is disposed between the metal frame 30 and the source electrode 23, it is not necessary to fill the entire space between the metal frame 30 and the source electrode 23 with the conductive bonding material. In this way, during the manufacturing process, the conductive bonding material can be prevented from being damaged when the metal frame 30 is disposed on the conductive bonding material 53, and the reliability of the semiconductor device is not easily lowered. Further, since the stress relaxation structure has a structure in which at least one convex portion 41 is formed at a position on the metal plate 40 corresponding to the source electrode 23, even when the distance between the metal frame 30 and the source electrode 23 is increased, the distance between the metal plate 40 and the source electrode 23 (see reference symbol t11 in fig. 1 a) can be easily maintained at a predetermined distance, and thus the conductive bonding material 53 between the metal plate 40 and the metal frame 30 does not need to be excessively thick, and the conductive bonding material is less likely to be pressed, and the reliability of the semiconductor device is less likely to be lowered.

In addition, according to the semiconductor device 100 of the first embodiment, since the stress relaxing structure has a structure in which the thickness of the metal plate 40 is smaller than the thickness of the metal frame 30, the stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 and the metal plate 40 between the semiconductor element 20 and the metal frame 30 can be absorbed by the deformation of the metal plate itself. In this way, stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 and the metal plate 40 between the semiconductor element 20 and the metal frame 30 can be further relaxed. Further, since the stress relaxation structure has a structure in which the thickness of the metal plate 40 is smaller than the thickness of the metal frame 30 and at least one convex portion 41 is formed at a position on the metal plate 40 corresponding to the source electrode 23, the thickness of the conductive bonding material 52 disposed between the region of the metal plate 40 where the convex portion 41 is not formed and the source electrode 23 can be maintained at a predetermined value or more, and the conductive bonding material 52 disposed between the region where the convex portion 41 is not formed and the source electrode 23 can absorb the deformation of the metal plate 40 in addition to the deformation of the metal plate 40 itself to absorb the stress, and thus the stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 between the semiconductor element 20 and the metal frame 30 and the metal plate 40 can be further relaxed.

In addition, according to the semiconductor device 100 of the first embodiment, since the stress relaxation structure has a structure in which at least one convex portion 41 is formed at a position corresponding to the source electrode 23 on the metal plate 40 and the conductive bonding material 52 is intensively bonded around the position of the convex portion 41 of the metal plate 40, the motor and the metal plate can be reliably bonded by forming the starting point of the solder wetting and spreading. Further, by providing the metal plate with the notch so as to avoid the sub-electrode, wet spreading of the solder to the sub-electrode can be suppressed, and the possibility of short-circuiting between the main electrode and the sub-electrode can be reduced.

In addition, according to the semiconductor device 100 of the first embodiment, since the stress relaxing structure has a structure in which the metal plate 40 is formed of an elastic member, the metal plate 40 itself is easily elastically deformed, and the stress is more easily absorbed.

According to the semiconductor device 100 of the first embodiment, since the metal plate 40 is symmetrical with respect to the center of the source electrode 23, the metal plate 40 can be stably disposed on the source electrode 23. Thus, the metal plate 40 is less likely to be inclined during the manufacturing process, and the thickness of the conductive bonding material 52 between the metal plate 40 and the source electrode 23 is easily kept constant, thereby maintaining high reliability.

In addition, according to the semiconductor device 100 of the first embodiment, since the semiconductor element 20 has the source electrode 23 as the main electrode and the gate electrode 24 as the sub-electrode formed on the surface of the semiconductor element 20 opposite to the side facing the circuit board 10, the semiconductor element 20 is a semiconductor device suitable for an electronic device using a large current

According to the semiconductor device 100 of the first embodiment, since the circuit board 10 uses a ceramic substrate (alumina ceramic substrate), the difference in linear expansion coefficient between the circuit board and the semiconductor element 20 is small, and thus stress is not easily applied to the conductive bonding material 52 between the semiconductor element 20 and the circuit board 10.

According to the semiconductor device 100 of the first embodiment, since the area of the metal plate 40 is smaller than the area of the semiconductor element 20 in plan view, the entire metal plate 40 can be placed on the conductive bonding material 52. Thus, during the manufacturing process, the metal plates 40 can be joined in a stable state during solder reflow, and mounting misalignment is less likely to occur.

[ second embodiment ] to provide a medicine for treating diabetes

Fig. 3 is an enlarged plan view of a main portion of a semiconductor device 100a according to a second embodiment. Fig. 4 is an exploded view of the periphery of the semiconductor element 20 according to the second embodiment.

The semiconductor device 100a according to the second embodiment basically has the same structure as the semiconductor device 100 according to the first embodiment, but the structure of the main electrode is different from the semiconductor device 100 according to the first embodiment. That is, in the semiconductor device 100a according to the second embodiment, the source electrode 23a has a plurality of regions, and the stress relaxation structure has the convex portions 41 formed on the metal plate 40 at positions corresponding to the plurality of regions of the source electrode 23.

The source electrode 23a is formed of 4 rectangular regions as a plurality of regions, and these regions are separated from each other on the surface by an insulating layer, a groove, or the like, but on the inner side, these regions are electrically connected to each other.

The metal plate 40a is arranged to overlap the source electrode 23a in plan view, and covers most of the source electrode 23 a. The metal plate 40a has a rectangular shape as a whole, and a notch is provided on one side of the gate electrode and the opposite side (see fig. 3).

The metal plate 40a is formed at a position corresponding to the source electrode 23 on the side facing the source electrode 23a, specifically, at a position corresponding to a plurality of regions of the source electrode 23 a. Two convex portions (one in the vicinity of the end portion) are formed in a region of the metal plate 40a corresponding to a region distant from the gate electrode 24 (where no notch is formed) among the plurality of regions of the source electrode 23, and one convex portion is formed in a central portion of each region of the metal plate 40a corresponding to a region close to the gate electrode 24 (where a notch is formed) among the plurality of regions of the source electrode 23.

In the second embodiment, as shown in fig. 4, a conductive bonding material (e.g., solder) is placed on each region of the source electrode 23a by a dispenser or the like, a metal plate 40a is disposed on the conductive bonding material, a conductive bonding material 53 is further placed on the metal plate 40a, and the metal frame 30 is placed on the conductive bonding material 53.

As described above, although the structure of the main electrode of the semiconductor device 100a according to the second embodiment is different from the semiconductor device 100 according to the first embodiment, since the stress relaxation structure has at least one protrusion 41 passing through the protrusion 41 formed at a position corresponding to the main electrode (source electrode) 23a on the metal plate 40a as in the semiconductor device 100 according to the first embodiment, the distance of the height of at least one protrusion 41 can be secured between the metal plate 40a and the source electrode 23a, and the distance between the region where the protrusion 41 is not formed and the source electrode 23a can be maintained at a constant value or more. In this way, the thickness of the conductive bonding material 52 disposed between the region of the metal plate 40a where the convex portion 41 is not formed and the source electrode 23a is kept at a constant value or more, and the stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 and the metal plate 40a between the semiconductor element 20 and the metal frame 30 can be relaxed.

In addition, according to the semiconductor device 100a of the second embodiment, since the source electrode 23a has a plurality of regions, the current distribution is less likely to be varied and the current can be made uniform, as compared with the case where the source region is a single region (for example, in the central portion and the peripheral portion of the source electrode). Further, there is an effect of dispersing stress applied to the conductive bonding material between the metal plate 40a and the source electrode 23a, and thermal stress is more easily relaxed.

According to the semiconductor device 100a of the second embodiment, since the source electrode 23a has a plurality of regions and the stress relaxation structure has a structure in which the convex portions 41 are formed at positions on the metal plate 40a corresponding to the plurality of regions of the source electrode 23a, the conductive bonding material 52 can be bonded to the convex portions 41 in a concentrated manner in the respective regions of the source electrode 23a, and thus, the metal plate 40a and the respective regions of the source electrode 23a can be reliably connected to each other, and a large current can more easily flow. Further, since the convex portion 41 is formed at the position corresponding to each region of the source electrode 23a, the thickness of the conductive bonding material 52 between each region and the metal plate 40a can be kept at a constant value or more, so that stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 between the semiconductor element 20 and the metal frame 30 can be relaxed, and the reliability of the semiconductor device can be improved.

In addition, according to the semiconductor device 100a of the second embodiment, since the plurality of regions of the source electrode 23a are formed independently, the conductive bonding material 52 is intensively bonded around the convex portion 41 in each region. Therefore, the conductive bonding materials 52 and 53 between the source electrode 23a and the metal frame 30 are easily secured, and the reliability of the semiconductor device is improved.

In addition, according to the semiconductor device 100a of the second embodiment, since the metal plate 40a is provided with the notch so as to avoid the gate electrode 24, the distance between the metal plate 40a and the gate electrode 24, and further, between the conductive bonding materials 52 and 53 and the gate electrode 24 can be kept constant or more, and thus, the occurrence of short circuit between the source electrode 23a and the gate electrode 24 can be prevented.

Further, the semiconductor device 100 according to the first embodiment has the same structure as the semiconductor device 100 according to the first embodiment except for the structure of the source electrode 100 according to the second embodiment, and therefore has the corresponding effects of the semiconductor device 100 according to the first embodiment.

[ DEFORMATION (APPLICATION EXAMPLE) ]

Fig. 5 is a diagram for explaining a semiconductor device 100b according to a modification. Fig. 5(a) is an external perspective view of the semiconductor device 100B, and fig. 5(B) is a view of the internal structure of the semiconductor device 100B. In fig. 5(B), the molded resin 60 is not shown. Fig. 6 is a circuit diagram of a semiconductor device 100b according to a modification. Fig. 7 is a cross-sectional view of a semiconductor device 100b according to a modification.

The semiconductor device 100B according to the modification basically has the same configuration as the semiconductor device 100a according to the second embodiment, but differs in that a plurality of semiconductor elements are mounted on the circuit board 10a, and the metal plate 40 is arranged between the source electrodes (main electrodes) 23S1 and 23S2 of the semiconductor elements and the metal frames 30a and 30B, that is, in the semiconductor device 100B according to the modification, two semiconductor elements, i.e., the semiconductor element 20a and the semiconductor element 20B, are incorporated as the semiconductor elements (see fig. 5B and 6)).

First, the appearance of the semiconductor device 100b according to the modification will be described.

The semiconductor device 100b of the modification is sealed with the mold resin 60, and 5 terminals (70D1, 70S2, 70S1(D2), 70G1, 70G2) for electrical connection to an external circuit are exposed to the outside of the mold resin 60 (see fig. 5 a). In addition, a heat radiation member (not shown) is also exposed to improve the heat radiation effect. The terminals 70D1, 70S2, 70S1(D2) as the main current paths have a large cross-sectional area so that a large current can flow. In the semiconductor device 100b of the modification, each terminal is formed by bending a metal frame extending from the inside toward the front surface side (semiconductor element mounting surface side) when viewed from the circuit board 10a side.

Next, the internal structure of the semiconductor device 100b according to the modification will be described.

In the semiconductor device 100b of the modification, the semiconductor element 20a and the semiconductor element 20b are connected in series, and the source electrode 23S1 of the semiconductor element 20a and the drain electrode 22D1 of the semiconductor element 20b are connected (see fig. 6).

The circuit board 10a has pattern wiring layers 12D1, 12D2, 12G1, 12G2 (see fig. 5B).

The semiconductor element 20a has a drain electrode 22D1 on one surface side and a source electrode 23S1 and a gate electrode 24G1 on the other surface side. The semiconductor element 20B has a drain electrode 22D2 on one surface side and a source electrode 23S2 and a gate electrode 24G2 on the other surface side (see fig. 5B).

The semiconductor element 20a is mounted on the pattern wiring layer 12D1 such that the drain electrode 22D1 faces the pattern wiring layer 12D1, and the semiconductor element 20b is mounted on the pattern wiring layer 12D2 such that the drain electrode 22D2 faces the pattern wiring layer 12D 2.

The terminal 70D1 is connected to the drain 22D1 of the semiconductor element 20a via the pattern wiring layer 12D 1.

The terminal 70G1 is electrically connected to the gate electrode 24G1 of the semiconductor element 20a via the wiring member 32G1 and the pattern wiring layer 12G 1.

The terminal 70S1(D2) is connected to the source electrode 23S1 of the semiconductor element 20a through the pattern wiring layer 12D2 and the metal frame 30 a. In addition, the terminal 70S1(D2) is also connected to the drain electrode 22D2 of the semiconductor element 20b via the pattern wiring layer 12D 2.

The terminal 70G2 is electrically connected to the gate electrode 24G2 of the semiconductor element 20b via the wiring member 32G2 and the pattern wiring layer 12G 2.

The terminal 70S2 is formed by bending an end portion of the metal frame 30b, and is connected to the source electrode of the semiconductor element 20 b.

The metal frame 30a is a clip lead (so-called connector) for connecting the semiconductor element 20a and the pattern wiring layer 12D2, and includes: the flat plate-like metal plate 40 (see fig. 7) disposed between the metal frame 30a and the source electrode 23S1, and the conductive bonding material 52 is disposed between the metal plate 40 and the source electrode 23S1 and between the metal plate 40 and the metal frame 30 a. The metal plate 40a and the conductive bonding material 52 constitute a stress relaxation structure for relaxing stress applied to the metal plate 40a and the conductive bonding material 52 between the metal frame 30a and the semiconductor element 20 a.

One end of the metal frame 30b is connected to the source electrode 23S2 of the semiconductor element 20b, and the other end is a terminal 70S2, and the metal frame includes: a flat plate-like metal plate 40 (the structure is the same as that of fig. 7) disposed between the metal frame 30b and the source electrode 23S2, and conductive bonding materials 52 are disposed between the metal plate 40 and the source electrode 23S2 and between the metal plate 40 and the metal frame 30 b. The metal plate 40b and the conductive bonding material 52 constitute a stress relaxation structure for relaxing stress applied to the metal plate 40b and the conductive bonding material 52 between the metal frame 30b and the semiconductor element 20 b.

The semiconductor device 100b according to the modification has the same configuration as the semiconductor device 100a according to the second embodiment except that two semiconductor elements, i.e., the semiconductor element 20a and the semiconductor element 20b, are incorporated, and therefore has the corresponding effects of the semiconductor device 100a according to the second embodiment

[ third embodiment ]

Fig. 8 is a diagram for explaining a semiconductor device 100c according to the third embodiment. Fig. 8(a) is a perspective view of the semiconductor device 100c, and fig. 8(B) is a plan view of the internal structure of the semiconductor device 100 c. In fig. 8(B), the molded resin 60a is not shown for the sake of simplicity of explanation. Fig. 9 is an enlarged cross-sectional view of a main portion of a semiconductor device 100c according to a third embodiment (a cross-sectional view B-B in fig. 8B).

The semiconductor device 100c according to the third embodiment basically has the same configuration as the semiconductor device 100b according to the modification, but is different from the semiconductor device 100b according to the modification in the configuration of the connection member, the metal frame, and the external terminal. That is, in the semiconductor device 100c according to the third embodiment, as shown in fig. 8B, the connection members and the metal frame are flat leads (lead frames) 30c, 30d, 30e, 30f, and 30g, the external terminals penetrate the leads, one terminal of the external terminal protrudes outside, and the other terminal is a pin terminal connected to the globoid wiring layer of the power board.

The pin terminal is an elongated cylindrical conductive pin having a flange portion with a large diameter at the center. The pin terminal is used as a terminal for external connection and as a member for connecting a lead and a wiring pattern.

The pin terminal is composed of: a lead terminal 70G1 connected to the gate electrode 24G1 of the semiconductor element 20a, a lead terminal 70D1 connected to the drain electrode 22D1 of the semiconductor element 20a, a lead terminal 70S1(D2) connected to the source electrode 23S1 of the semiconductor element 20a and the drain electrode 22D2 of the semiconductor element 20b, 3 lead terminals 70S2 connected to the source electrode 23S2 of the semiconductor element 20b, and a lead terminal 70G2 connected to the gate electrode 24G2 of the semiconductor element 20 b.

As shown in fig. 8(B), the semiconductor device 100c according to the third embodiment includes two semiconductor elements 20a and 20B. These two semiconductor elements have a drain electrode (not shown) formed on the patterned wiring layer 12 side of the circuit board 10, and source electrodes 24G1 and 24G2 and gate electrodes 24G1 and 24G2 on the opposite side of the circuit board 10. Further, a circuit in which 2 switching elements are connected in series is configured by 2 semiconductor elements 20a and 20b, the pattern wiring layer 12 of the circuit board 10, the leads 30c and 30d, and the respective pin terminals (the circuit configuration is the same as that of fig. 6).

As shown in fig. 8(B), the lead 30c is disposed on the source electrode 23S1 of the semiconductor element 20a, and includes: a first electrode connection portion 33c electrically connected to the source electrode 23S1 of the semiconductor element 20a, a second electrode connection portion 34c connected to the pattern wiring layer 12D1 through the pin terminal 70S1(D1), and a third electrode connection portion 35c connected to the motor portion (not shown) of the pattern wiring layer through the pin terminal 70S1 (D2).

As shown in fig. 8(B), the lead 30d is disposed on the source electrode 23S2 of the semiconductor element 20B, and includes: a first electrode connection portion 33d electrically connected to the source electrode 23S2 of the semiconductor element 20b via a conductive bonding material, and 2 second electrode connection portions 34d connected to the pattern wiring layer 12S2 via the pin terminals 70S 2.

The stress relaxation structure has at least one convex portion 41 formed at a position corresponding to the source electrodes 23S1 and 23S2 on the metal plate 40 (see fig. 9).

As described above, although the semiconductor device 100c according to the third embodiment differs from the semiconductor device 100b according to the modification in the structure of the connection member and the external terminal, since the stress relaxing structure has the structure in which at least one convex portion 41 is formed at the position corresponding to the source electrodes 23S1 and 23S2 on the metal plate 40 as in the semiconductor device 100c according to the modification, the convex portion 41 can secure a space at least corresponding to the height of the convex portion 41 between the metal plate 40 and the source electrodes 23S2 and 23S2, and a certain degree of space can be maintained between the region where the convex portion 41 is not formed and the source electrodes 23S2 and 23S 2. Therefore, the thickness of the conductive bonding material 52 disposed between the region of the metal plate 40 where the convex portion 41 is not formed and the source electrodes 23S1, 23S2 can be kept at a predetermined value or more, and thus stress (i.e., thermal stress) acting on the conductive bonding materials 52, 53 between the semiconductor element 20 and the metal frames 30c, 30d and the metal plate 40 can be suppressed.

The semiconductor device 100c according to the third embodiment includes the lead terminals 70S1(D2) and 70S2 that penetrate the metal frames 30c and 30D, protrude outward at one end, and are connected to the pattern wiring layer 12 of the circuit board 10 at the other end. With such a configuration, since the metal frames (leads) 30c and 30D are fixed to the circuit board 10 via the pin terminals 70S1(D2) and 70S2, even when the metal frames (leads) 30b and 30c are difficult to self-align, a difference in thermal contraction stress applied to the conductive bonding materials 52 and 53 is unlikely to occur, and thus variations in the conductive bonding materials are unlikely to occur. Thus, when the conductive bonding materials 52 and 53 are cured (when solder is condensed), the semiconductor elements 20a and 20b are less likely to be inclined, and the thickness of the conductive bonding material can be kept constant, which is a highly reliable semiconductor device.

In addition, according to the semiconductor device 100c according to the third embodiment, the present invention is not only applicable to the case where a clip lead is used as a metal frame (see reference numeral 30a in fig. 5B). ) Or a part of the terminal (see reference numeral 70S2 in fig. 5B), the same applies to the case where a lead (lead frame) connecting an electrode of a semiconductor element and a terminal (pin terminal) is used.

Further, since the semiconductor device 100c according to the third embodiment has the same configuration as the semiconductor device 100b according to the modification except for the configuration of the connection member and the external terminal, the semiconductor device 100b according to the modification has the advantageous effects.

[ fourth embodiment ] A

Fig. 10 is a diagram for explaining a semiconductor device 100d according to the fourth embodiment. Fig. 10(a) is an enlarged plan view of a main part for explaining the metal plate 40B, fig. 10(B) is an enlarged sectional view of a main part of the semiconductor device 100d, and the illustration of the mold resin 60 is omitted.

The semiconductor device 100d according to the fourth embodiment basically has the same structure as the semiconductor device 100a according to the second embodiment, but is different from the semiconductor device 100a according to the second embodiment in the structure of a metal plate. That is, in the semiconductor device 100d according to the fourth embodiment, as shown in fig. 10, the stress relaxation structure has not only the convex portion 41 formed on the metal plate 40b on the source electrode 23 side but also the convex portion 42 formed on the metal plate 40b on the side opposite to the source electrode 23 side (on the metal frame 30 side) (that is, the convex portion is formed on both surfaces of the metal plate 40b in the stress relaxation structure).

In the fourth embodiment, the convex portion 42 has substantially the same height as the convex portion 41, but may have any other suitable height.

For example, the height of the convex portion 42 may be set to reach the metal frame 30. In this case, the interval corresponding to the height of the projection 42 (i.e., the interval between the metal frame 30 and the metal plate 40 b) can be reliably maintained at a certain value or more. Thus, the thickness of the conductive bonding material 53 between the metal plate 40b and the metal frame 30 can be reliably maintained at a predetermined value or more, and the stress applied to the conductive bonding material 53 can be relaxed. The position of the projection 42 on the plane can be appropriately arranged according to the actual situation.

As described above, the semiconductor device 100d according to the fourth embodiment is different from the semiconductor device 100a according to the second embodiment in the structure of the metal plate, but has a structure in which at least one projection 41 is formed at a position corresponding to the source electrode 23 on the metal plate 40b, as in the semiconductor device 100a according to the second embodiment, and therefore, the projection 41 can secure a space having a height of at least one projection 41 between the metal plate 40b and the source electrode (main electrode) 23, and the space between the source electrode 23 and a region where the projection 41 is not formed can be maintained at a constant value or more. Thus, the thickness of the conductive bonding material 52 disposed between the region of the metal plate 40b where the convex portion 41 is not formed and the source electrode 23 is kept at a constant value or more, and the stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 and the metal plate 40b between the semiconductor element 20 and the metal frame 30 can be relaxed.

In addition, the upper portion of the convex portion 42 may reach the vicinity of the metal frame 30, and the lower portion of the convex portion 41 may reach the vicinity of the source electrode 23, that is, the length from the top of the convex portion 42 to the top of the convex portion 41 may be substantially equal to the length between the semiconductor element 20 and the metal frame 30.

Further, since the semiconductor device 100d according to the fourth embodiment has the same configuration as the semiconductor device 100a according to the second embodiment except for the configuration of the connection member and the external terminal, the semiconductor device 100a according to the second embodiment also has the corresponding effects.

[ fifth embodiment ] A

Fig. 11 is an enlarged cross-sectional view of a main portion of a semiconductor device 100e according to a fifth embodiment.

The semiconductor device 100e according to the fifth embodiment basically has the same structure as the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment, but is different from the semiconductor device according to the first embodiment in the structure of the metal frame. That is, in the semiconductor device 100e according to the fifth embodiment, the convex portion 31 is also formed at a position corresponding to the metal plate 40 on the metal frame 30 h.

The convex portion 31 of the metal frame 30h is formed by pressing the metal frame 30 h. Since the metal frame 30h is relatively thick in order to allow a large current to flow, if the metal frame 30h is subjected to press working, a relatively large convex portion (up to the height of the convex portion 31 with respect to a region of the metal frame where the convex portion 31 is not formed) and a convex portion having a large width are formed. However, as long as the metal plate 40 is provided, the distance between the metal plate 40 and the metal frame 30h can be maintained at a constant value or more without forming a projection corresponding to the minute source electrode 23.

As described above, although the semiconductor device 100e according to the fifth embodiment is different from the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment in the structure of the metal frame, since the stress relaxation structure has a structure in which at least one convex portion 41 is formed at a position corresponding to the source electrode 23 on the metal plate 40 as in the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment, the gap having at least one height of the convex portion 41 between the metal plate 40 and the source electrode can be secured by the convex portion 41, and the gap between the region where the convex portion 41 is not formed and the source electrode 23 can be maintained at a constant value or more. Thus, the thickness of the conductive bonding material 52 disposed between the region of the metal plate 40 where the convex portion 41 is not formed and the source electrode 23 is kept at a predetermined value or more, and the stress (for example, thermal stress) acting on the conductive bonding materials 52 and 53 between the semiconductor element 20 and the metal frame 30 and the metal plate 40 can be relaxed.

In addition, according to the semiconductor device 100e of the fifth embodiment, since the convex portion 31 is formed also at the position corresponding to the metal plate 40 on the metal frame 30h, the convex portion 31 can secure a space at least corresponding to the height of the convex portion 31 between the metal frame 30h and the metal plate 40, and the space between the region where the convex portion 31 is not formed and the metal plate 40 can be maintained at a constant value or more. Thus, the thickness of the conductive bonding material 53 disposed between the region where the convex portion 31 is not formed and the metal plate 40 can be kept at a predetermined value or more, and stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element 20 and the metal frame 30h can be relaxed.

Further, since the semiconductor device 100e according to the fifth embodiment has the same structure as the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment except for the structure of the metal frame, the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment has the corresponding effects.

[ embodiments six to thirteen ]

Fig. 12 is a diagram for explaining semiconductor devices 100f to 100h according to the sixth to eighth embodiments. Fig. 12(a) is an enlarged cross-sectional view of a main portion of a semiconductor device 100f according to a sixth embodiment, fig. 12(B) is an enlarged cross-sectional view of a main portion of a semiconductor device 100g according to a seventh embodiment, and fig. 12(C) is an enlarged cross-sectional view of a main portion of a semiconductor device 100h according to an eighth embodiment. Fig. 13 is a diagram for explaining semiconductor devices 100i to 100k according to ninth to eleventh embodiments. Fig. 13(a) is a diagram for explaining a semiconductor device 100i according to the ninth embodiment, fig. 13(B) is a diagram for explaining a semiconductor device 100j according to the tenth embodiment, and fig. 13(C) is a diagram for explaining a semiconductor device 100k according to the eleventh embodiment. Fig. 14 is an enlarged cross-sectional view of a main portion of a semiconductor device 100l according to a twelfth embodiment. Fig. 15 is a diagram illustrating a semiconductor device 100m according to a thirteenth embodiment. Fig. 15(a) is a circuit diagram of a main part of the semiconductor device 100m, and fig. 15 (B) is an enlarged cross-sectional view of a main part of the semiconductor device 100 m.

The semiconductor devices 100f to 100m according to embodiments six to thirteen have basically the same structure as the semiconductor device 100 of embodiment one or the semiconductor device 100a of embodiment two, but are different from the semiconductor device 100a of embodiment two in at least one structure of a metal plate, a convex portion, and a source electrode.

In a semiconductor device 100f according to a sixth embodiment, as shown in fig. 12(a), a metal plate 40c is substantially rectangular without a notch. Another difference is that the projection 41 is formed at the same position in each of the four regions of the source electrode 23 a. Thus, the current flowing through the four regions is more easily uniformized.

In the semiconductor device 100g according to the seventh embodiment, as shown in fig. 12B, the source electrode 23a is divided into a plurality of regions (four regions), but of the four regions, a region close to the gate electrode 24 is formed to be short, and the shape of the metal plate 40d corresponds to the shape of the source electrode 23B (inverted C-shape). This can more reliably prevent the conductive bonding materials 52 and 53 on the source electrode side from short-circuiting with the gate electrode 24.

In the semiconductor device 100h according to the eighth embodiment, as shown in fig. 12(C), the source electrode 23C has four regions, but these regions are not independent of each other, and one end portion of each region is connected to each other, and one electrode is zigzag-shaped when viewed from a plane. The metal plate 40 has a substantially rectangular shape in plan view, and has a convex portion formed at a position corresponding to the laterally long region of the source electrode 23 c.

In the semiconductor device 100i according to the ninth embodiment, as shown in fig. 13 a, the source electrode 23d is divided into three regions, but is not completely separated, and two places may be connected between the plurality of regions (the regions dividing the plurality of regions may be holes), but one place may be connected between the plurality of regions (the regions dividing the plurality of regions may be slit-shaped, see fig. 13 a). In addition, the metal plate 40e and the source 23d are both cut in a circular shape so as to avoid the gate electrode 24. The metal plate 40e has a substantially rectangular shape, and has convex portions 41 formed at each corner and at the center thereof. As described above, the present invention can be applied even if the shape of the source electrode 23d is a special shape.

As shown in fig. 13B, in a semiconductor device 100j according to a tenth embodiment, a source electrode 23e and a drain electrode 22a as main electrodes and a gate electrode as a sub electrode are formed on a surface of a semiconductor element 20a on the metal frame side (a surface on the opposite side of the circuit board 10), a metal plate 40f is disposed between the metal frame (not shown) and the source electrode 23e, and a metal plate 40g is disposed between the metal frame (not shown) and the drain electrode 22 a.

In addition, in the semiconductor device 100k according to the eleventh embodiment, as shown in fig. 13(C), the source electrode 23f and the drain electrode 22b are each divided into a plurality of regions.

In a semiconductor device 100l according to a twelfth embodiment, as shown in fig. 14, the source electrode is divided into a plurality of regions, and the metal plates 40j and 40k and the conductive bonding materials 52 and 53 are arranged in each of the plurality of regions. The metal frame 30 is common. Alternatively, a different electrode (but the potential must be the same) may be used instead of the divided source electrode.

In the semiconductor device 100l according to the twelfth embodiment, as shown in fig. 14, the main electrodes of different semiconductor elements may be connected to each other by a common metal frame, and the metal plates may be disposed between the common metal frame and each of the main electrodes.

In the semiconductor device 100m according to the thirteenth embodiment, as shown in fig. 15, diodes may be arranged as semiconductor elements on the circuit board 10, and two diodes may be connected in parallel to a common wiring pattern.

As described above, although the semiconductor devices 100e to 100m according to the fifth to thirteenth embodiments are different from the semiconductor device 100a according to the first embodiment or the second embodiment in the structure of at least one of the metal plate, the projection, and the source electrode, the stress relaxing structure has a structure in which at least one projection is formed at a position on the metal plate corresponding to the main electrode, and therefore, as in the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment, the projection can secure a space having at least one projection height between the metal plate and the main electrode, and the space between the region where no projection is formed and the main electrode can be maintained at a predetermined amount or more. In this way, the thickness of the conductive bonding material disposed between the region of the metal plate where the projection is not formed and the main electrode can be kept at a predetermined value or more, and the stress (for example, thermal stress) acting on the conductive bonding material between the semiconductor element and the metal frame and the metal plate can be relaxed.

Further, since the semiconductor devices 100e to 100m according to fifth to thirteenth embodiments have the same configuration as the semiconductor device 100a according to the first embodiment or the semiconductor device 100a according to the second embodiment except for at least one of the metal plate, the convex portion, and the source electrode, the semiconductor device 100 according to the first embodiment or the semiconductor device 100a according to the second embodiment also has the effect.

The present invention has been described above based on the above embodiments, and the present invention is not limited to the above embodiments. The present invention can be implemented in various ways without departing from the scope of the invention, and for example, the following modifications can be made.

(1) The number, position, and the like of the components described in the above embodiments are merely examples, and may be changed within a range not to impair the effect of the present invention.

(2) In the above embodiments three to thirteen, the semiconductor device 100 of the first embodiment or the semiconductor device 100a of the second embodiment is described as a base, but the present invention is not limited thereto. The present invention can also be applied to a semiconductor device in which the features of each embodiment are combined.

(3) Although the MOSFET is used as the semiconductor element in the first to twelfth embodiments and the diode is used as the semiconductor element in the thirteenth embodiment, the present invention is not limited thereto. In the first to twelfth embodiments, a diode may be used as the semiconductor element, in the third embodiment, a MOSFET may be used as the semiconductor element, and in the first to thirteenth embodiments, a switching element other than a MOSFET such as an IGBT, a rectifying element such as a schottky barrier diode, a control rectifying element such as a thyristor, or another suitable element may be used.

Description of the symbols

10, 10a … circuit substrate; 11 … insulating substrate; 12 … pattern wiring layer; 13 … heat sink plate; 14 … semiconductor element mounting part; 15 … electrode portions; 20. 955 … semiconductor element; 21 … a substrate; 22 … drain electrode; 23 … source electrode (main electrode); 24 … gate electrode (sub-electrode); 30 … metal frame (clip lead, terminal); 31. 941 … convex part (of metal frame); 32 … wiring members; 33 … a first electrode connection; 34 … a second electrode connection; 35c … third electrode connection; 40 … sheet metal; 41. 42 … (of sheet metal); 51. 52, 53, 54, 55 … conductive bonding material; 60 … molding resin; 70. a 911 … terminal; 100. 900 … semiconductor device.