JP2002217364A - Semiconductor mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of cracks of solder and damage of a semiconductor chip which are to be caused by temperature change, in a mounting structure wherein a semiconductor chip is bonded to a bus bar by using solder. SOLUTION: A thin metal plate 10A is arranged between the semiconductor chip 3 and the bus bar 1 which are bonded by using solders 4a, 4b, and has the same coefficient of linear expansion as that of the bus bar 1. Upper side protrusions 11 and lower side protrusions 12 are formed on the metal plate 10A. Tops of the respective protrusions are made to abut against the rear of the semiconductor chip 3 and the bus bar 1. Since the metal plate has the same coefficient of linear expansion as that of the bus bar, stress applied to the solder 4a between the bus bar and the metal plate is small. Since the metal plate is thin, stress of the solder 4b between the metal plate and the semiconductor chip is reduced. Inclination of the metal plate is prevented by the protrusions formed on the metal plate, and thickness of the solders 4a, 4b can be controlled to be always constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor mounting structure for mounting a semiconductor chip on a metal electrode plate.

[0002]

2. Description of the Related Art As a conventional semiconductor chip mounting structure,
There is a type such as a bus bar which is joined to an electrode plate via solder. Since the bonding structure using the solder has a role of releasing heat generated by the semiconductor chip and a role of making an electrical connection between the semiconductor chip and the bus bar when the semiconductor chip has electrodes on the front and back thereof. Therefore, it is necessary to ensure a reliable bonding state of the solder.

[0003] However, in general, when a semiconductor chip is bonded to a bus bar using Cu (copper) or the like via solder, when the semiconductor chip generates heat or when the ambient temperature repeatedly rises and falls due to the environment, Stress may be generated in the solder due to a difference in linear expansion coefficient between the semiconductor chip and the bus bar, and the solder may be cracked, or the semiconductor chip itself may be broken and malfunction. In order to reduce the stress, the thickness of the solder layer may be increased, but there is a limit to increasing the thickness of the solder having fluidity at the time of joining.

Therefore, as a countermeasure, as shown in FIG. 13, the coefficient of linear expansion between the bus bar 30 and the semiconductor chip 33 is close to that of Si (silicon) which is the material of the semiconductor chip.
A metal plate 35 made of a material such as o (molybdenum) or W (tungsten) is arranged, and the bus bar 30 and the metal plate 3
5 and between the metal plate 35 and the semiconductor chip 33 are connected by solders 37a and 37b, respectively. According to this, the semiconductor chip 33 and the bus bar 3
Since the total thickness of the solder between 0 is large and the linear expansion coefficients of the metal plate 35 and the semiconductor chip 33 are close to each other, high stress is not applied to the solder 37b therebetween and the semiconductor chip 33 is cracked. Not even.

[0005]

However, in the above-described conventional semiconductor mounting structure, the plane size of the metal plate 35 is larger than the size of the semiconductor chip 33, while the metal plate 35 is
The linear expansion coefficient of the metal plate 35 is considerably different from the linear expansion coefficient of the bus bar 30 in a situation where the thickness of the solder 37a itself between the metal bar 35 and the bus bar 30 is small. Therefore, the difference in the linear expansion coefficient between the metal plate 35 and the bus bar 30 due to the heat generation of the semiconductor chip 33 and the change in the environmental temperature still has an effect, and the solder 37a has the linear expansion coefficient difference between the bus bar 30 and the metal plate 35. Cracks are generated by the stress caused by the difference. For this reason, the problem that electrical and thermal problems occur is not necessarily solved. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a semiconductor mounting structure that does not cause cracks in a bonding solder or damage to a semiconductor chip due to heat generation of a semiconductor chip or a change in environmental temperature in view of the above conventional problems. And

[0006]

According to the present invention, there is provided a semiconductor mounting structure for mounting a semiconductor chip on a metal electrode plate, wherein the semiconductor chip is mounted between the semiconductor chip and the metal electrode plate by the metal electrode plate. A thin metal plate having a thinner thickness and closer to the metal electrode plate than the semiconductor chip or having the same linear expansion coefficient as the metal electrode plate is arranged, and the space between the metal electrode plate and the metal thin plate and between the semiconductor chip and the metal thin plate are arranged. Joining was performed with a joining material.

According to a second aspect of the present invention, an upper protrusion protruding toward the semiconductor chip and a lower protrusion protruding toward the metal electrode plate are formed on the thin metal plate, and the top of the upper protrusion is formed on the semiconductor chip. The lower convex portion was in contact with the metal electrode plate. According to a third aspect of the present invention, the upper convex portion and the lower convex portion are formed so as to be positioned inside the peripheral contour of the semiconductor chip.

According to a fourth aspect of the present invention, the lower convex portion of the metal thin plate has a bead shape, is formed at a position overlapping the peripheral contour of the semiconductor chip, and the upper convex portion is formed inside the lower convex portion. It was taken. In the portion where the lower convex portion is formed, the concave portion is depressed by the amount of protrusion of the lower convex portion 14, so that the gap between the edge of the semiconductor chip and the thin metal plate increases.

According to a fifth aspect of the present invention, the bead-shaped lower convex portion is continuous along the peripheral contour of the semiconductor chip so as to form a quadrangular planar shape. In the invention according to claim 6, the upper convex portion includes a leg extending to the edge of the metal sheet.

According to a seventh aspect of the present invention, the upper convex portion of the metal thin plate has a bead shape and extends from the inside of the peripheral contour line of the semiconductor chip to the periphery of the metal thin plate, and the lower convex portion has a bead shape and has a peripheral shape of the semiconductor chip. The diagonal line of the metal sheet extends from the inside of the line to the corner of the metal sheet.

According to the invention of claim 8, the metal electrode plate is made of copper or aluminum or an alloy containing them, and the thin metal plate is made of the same metal material as the metal electrode plate. High degree of stress absorption and heat dissipation at the joint,
Electrical losses are also reduced.

[0012]

According to the first aspect of the present invention, in a semiconductor mounting structure in which a semiconductor chip is mounted on a metal electrode plate with a bonding material, the thickness between the semiconductor chip and the metal electrode plate at the bonding portion is smaller than that of the metal electrode plate and the metal is thin. Since a metal thin plate having a coefficient of linear expansion substantially similar to that of the electrode plate is arranged, the stress of the bonding material between the metal electrode plate and the metal thin plate against heat generation of the semiconductor chip and a change in environmental temperature is reduced, and The stress applied to the bonding material between the semiconductor chip and the semiconductor chip is also reduced, which has the effect of maintaining long-term reliability.

According to a second aspect of the present invention, an upper convex portion and a lower convex portion are formed on a metal thin plate, and the top portion 15a of the upper convex portion is in contact with the semiconductor chip, and the lower convex portion is in contact with the metal electrode plate. Since the thickness of the bonding material above and below the metal thin plate can be controlled to be constant, the semiconductor chip can be held horizontally with respect to the metal electrode plate. According to the third aspect of the present invention, since the upper convex portion and the lower convex portion are respectively positioned inside the peripheral contour of the semiconductor chip, the metal sheet can be further prevented from warping under the semiconductor chip. In addition, since the area of the thin metal plate can be reduced, the stress received from the metal electrode plate can be reduced.

According to a fourth aspect of the present invention, since the lower convex portion of the thin metal plate is formed in a bead shape and positioned so as to overlap the peripheral contour of the semiconductor chip, the gap between the edge of the semiconductor chip and the thin metal plate increases, and the joining material is increased. When the thickness of the metal is increased, the effect of reducing the stress that becomes severe at the periphery is large. In particular, the invention according to claim 5 is characterized in that the bead-shaped lower convex portion is continuous along the peripheral contour line of the semiconductor chip so as to form a quadrangular planar shape, so that the bonding material is formed along the entire periphery of the semiconductor chip. And the stress is further reduced.

According to a sixth aspect of the present invention, the bead-shaped upper convex portion includes the leg portion extending to the edge of the metal sheet.
The leg serves as a void escape passage, and voids remaining at the joint are reduced.

According to a seventh aspect of the present invention, the upper and lower bead-shaped protrusions of the metal sheet are radially extended to the edges or corners, and particularly the lower protrusions extend diagonally to the corners of the metal sheet. Therefore, the upper and lower convex portions each serve as a passage for the void in the bonding material, and the thickness of the bonding material between the semiconductor chip and the metal thin plate increases at the corner where the stress is particularly concentrated, thereby alleviating the stress.

According to the invention of claim 8, the metal electrode plate is made of copper or aluminum or an alloy containing them, and the thin metal plate is made of the same metal-based material as the metal electrode plate. Loss can be reduced,
Since the heat conductivity is large, when the semiconductor chip generates heat, heat can be easily transferred to the metal electrode plate, and stable long-term reliability of the semiconductor mounting structure can be maintained.

[0018]

Embodiments of the present invention will be described below with reference to examples. FIG. 1 is a top view showing a first embodiment in which the present invention is applied to a mounting unit for an inverter circuit.
FIG. 2 is a sectional view taken along the line AA in FIG. FIG. 3 is a perspective view showing the positional relationship of the bus bars in this mounting unit, and omits the resin, the heat radiation sheet, and the heat sink.
The mounting unit 100 includes a bus bar 1 made of a metal plate and a resin base 2 having a case shape which is entirely opened upward.
a, 1b and 1c are molded. The bus bars 1a, 1b and 1c are made of Cu (copper), Al (aluminum) or an alloy containing these. The bus bars 1a and 1b are exposed on the bottom surface of the resin base 2, respectively, and the bus bar 1c is partially overlapped on the upper side of the bus bar 1b, and the bus bars are separated from each other and insulated.

Semiconductor chips 3a and 3b made of MOSFETs are joined to upper surfaces of bus bars 1a and 1b as metal electrode plates by joining portions 20, respectively. Each of the semiconductor chips 3a and 3b has a back surface joined to the bus bar as a drain electrode and an upper surface as a source electrode. The upper surface of the semiconductor chip 3a and the bus bar 1c are connected by a metal wire 5a.
The upper surface of a is connected to the gate terminal 6a by a metal wire 9a.

The upper surface of the semiconductor chip 3b and the bus bar 1a are connected by a metal wire 5b, and the upper surface of the semiconductor chip 3b is connected by a gate terminal 6b and a metal wire 9b. Thus, as shown in FIG. 4, a circuit in which the semiconductor chips 3a and 3b are connected in series is formed. The bus bar 1b serves as a P terminal of the circuit, the bus bar 1c serves as an N terminal, and the bus bar 1a serves as an output INV terminal.

A heat sink 8 is attached to the bottom surface of the resin base 2 from which the bus bars 1a and 1b are exposed via a heat insulating sheet 7 having electrical insulation. As a result, heat generated when the semiconductor chips 3a and 3b operate is transmitted to the heat sink 8 and radiated.

FIG. 5 is an enlarged cross-sectional view showing the junction between the semiconductor chips 3a and 3b. Since the structure of the bonding portion is the same for both semiconductor chips, the semiconductor chip and the bus bar will be described below with reference numerals 3 and 1.
In the joining portion 20, the metal thin plate 10 is arranged between the bus bar 1 and the semiconductor chip 3, and the metal thin plate 10 and the bus bar 1 are joined with the solder 4a as a joining material, and the semiconductor chip 3 and the metal thin plate 10 are joined. Similarly, they are joined with solder 4b as a joining material. The plane size of the thin metal plate 10 is set slightly larger than that of the semiconductor chip 3.

The metal sheet 10 is made of the same Cu as the bus bar 1,
It is made of Al or an alloy containing them, and its plate thickness is set thinner than the bus bar 1. As shown in the characteristic table of FIG. 6, Cu and Al, which are the materials of the metal sheet 10, have a relatively small Young's modulus, a large thermal conductivity, and a high electrical resistivity as compared with other materials Mo and W. small. The smaller the value of the Young's modulus, the softer and the greater the degree of absorption of the generated stress. The higher the thermal conductivity, the easier it is to conduct heat, which is effective for heat dissipation and heat diffusion. Further, the smaller the value of the electric resistivity, the smaller the electric loss. The electric loss is converted into heat, and the bus bar 1 and the thin metal plate 10 themselves become heat sources, thereby hindering the heat radiation from the semiconductor chip 3. It is desirable to be as small as possible.

The present embodiment is constructed as described above, and has the same linear expansion as the bus bar 1 between the bus bar 1 and the semiconductor chip 3 as a joint between the bus bar 1 (1a, 1b) and the semiconductor chip 3 (3a, 3b). Since the thin metal plate 10 having a coefficient is arranged and the thin metal plate 10 and the bus bar 1 and the semiconductor chip 3 and the thin metal plate 10 are joined by solder, the stress is dispersed to the two layers of solder. In particular, since the coefficient of linear expansion of the metal sheet 10 and the bus bar 1 is the same, the bus bar 1 against heat generation of the semiconductor chip 3 and a change in the environmental temperature.
The stress of the solder between the metal sheet 10 and the metal sheet 10 is reduced.

Further, when the semiconductor chip is joined to the bus bar with one layer of solder, the stress applied to the joining portion is reduced as the joining partner of the bus bar becomes thinner.
Also between the semiconductor chip 3 and the semiconductor chip 3, the thickness of the metal sheet 10 is made thinner than the bus bar 1, and the metal sheet 10
Is about the same size as the semiconductor chip 3 and smaller than the bus bar 1, so that despite the difference in linear expansion coefficient,
The stress applied to the solder 4b is further reduced. Therefore, the stress between the semiconductor chip and the bus bar is alleviated and reduced in a well-balanced manner, so that cracks do not occur in the upper and lower solders sandwiching the thin metal plate 10, and electrical and thermal problems are avoided.

Next, a second embodiment of the present invention will be described. In this case, a metal sheet disposed between a bus bar and a semiconductor chip is provided with a projection. FIG. 7 is a cross-sectional view showing a joint in this embodiment, and FIG. 8 is a view showing details of a metal thin plate. 8A is a plan view, FIG. 8B is a side view, and FIG. 8C is a sectional view taken along line BB in FIG. FIG. 7 corresponds to a cross section taken along the line CC in FIG. The metal sheet 10A of the present embodiment is made of a material having the same linear expansion coefficient as the bus bar 1 like the metal sheet 10 of the first embodiment, and has dot-shaped convex portions formed on the upper and lower sides.

Upper convex portion 11 protruding toward semiconductor chip 3
Are provided at four intersections at the center of the grid virtually drawn on the metal sheet 10A, and the lower projections 12 projecting toward the bus bar 1 are also at the same height,
It is provided at eight locations of the outer intersections surrounding the upper convex portion 11. As shown in FIG. 8A, the upper convex portion 11 and the lower convex portion 12 connect the semiconductor chip 3 to the metal thin plate 1.
All of them are located in the peripheral contour of the semiconductor chip 3 when they are superimposed on the center of 0A.

Particularly, as shown in FIG. 7, the apex of the upper convex portion 11 contacts the back surface of the semiconductor chip 3, the apex of the lower convex portion 12 contacts the bus bar 1, and the thin metal plate 10A and the bus bar 1 contact each other.
Are joined by solder 4a, and the thin metal plate 10A and the semiconductor chip 3 are joined by solder 4b. Upper convex part 11
And the height of the lower protruding portion 12 are the same, so that the thickness of the upper and lower solders sandwiching the thin metal plate 10A is the same. Other configurations are the same as those of the first embodiment.

The present embodiment is constructed as described above. As a joining portion between the bus bar 1 and the semiconductor chip 3, a metal sheet 10A having an upper convex portion 11 and a lower convex portion 12 between the bus bar 1 and the semiconductor chip 3 is provided. Since it is arranged and joined between the metal thin plate 10A and the bus bar 1 and between the semiconductor chip 3 and the metal thin plate 10A by solder, it has the same effect as that of the first embodiment, and has the same effect as the first embodiment. By bringing the apex into contact with the semiconductor chip 3 and the bus bar 1, the inclination of the thin metal plate 10A is suppressed, and the thickness of the upper and lower solders sandwiching the thin metal plate 10A can be constantly controlled.

FIGS. 9 and 10 show a third embodiment of the present invention. FIG. 9 is a cross-sectional view showing a joint, and FIG. 10 is a view showing details of a thin metal plate. 10A is a plan view, and FIG. 10B is a side view. FIG. 9 corresponds to a cross section taken along the line DD in FIG. The metal sheet 10B of the present embodiment is
As in the case of the thin metal plate 10 of this embodiment, the bus bar 1 is made of a material having the same linear expansion coefficient as that of the metal thin plate 10, and bead-shaped projections are formed on the upper and lower sides.

Upper convex portion 13 protruding toward semiconductor chip 3
Is provided in the center of the thin metal plate 10 </ b> B in a square shape, and the lower convex portion 14 protruding toward the bus bar 1 is also provided in a rectangular shape outside the upper convex portion 13. Upper convex part 13
The lower projection 14 and the lower projection 14 keep the height constant over the entire circumference, and the height of the upper projection 13 and the height of the lower projection 14 are set to be the same. The upper convex portion 13 is located within the peripheral contour of the semiconductor chip 3 when the semiconductor chip 3 is superimposed on the center of the thin metal plate 10B, and the lower convex portion 14 is represented by a virtual line as shown in FIG. It is set so as to overlap the peripheral contour of the semiconductor chip 3 shown.

In particular, as shown in FIG. 9, the apex of the upper convex portion 13 contacts the back surface of the semiconductor chip 3, the apex of the lower convex portion 14 contacts the bus bar 1, and the thin metal plate 10A and the bus bar 1
Are joined by solder 4a, and the thin metal plate 10A and the semiconductor chip 3 are joined by solder 4b. Metal sheet 10
The other configuration is the same as that of the first embodiment except that the structure is changed to the metal sheet 10B.

The present embodiment is constructed as described above, and as a joint portion between the bus bar 1 and the semiconductor chip 3, a bead-shaped upper convex portion 13 having a square shape formed between the bus bar 1 and the semiconductor chip 3, and a lower portion. A metal thin plate 10B having a side convex portion 14 is arranged, and the metal thin plate 10B and the bus bar 1 and the semiconductor chip 3 and the metal thin plate 10B are joined by soldering. The thickness of the solder 4b joined to the semiconductor chip 3 along the peripheral contour line of the semiconductor chip 3 is determined by the thickness of the lower convex portion 14 (that is, the semiconductor chip 3).
(When viewed from the side). As a result, the same effect as that of the second embodiment is obtained, and the stress at the peripheral end of the semiconductor chip 3 where the stress is normally concentrated is further reduced.

In the third embodiment, the upper convex portion 13 at the center of the thin metal plate 10B is formed in a bead square shape.
The central portion may be dot-shaped as in the second embodiment.

Next, a fourth embodiment of the present invention will be described. This is one in which the shape of the convex portion of the thin metal plate arranged between the bus bar and the semiconductor chip is different. FIG.
7A and 7B show a metal sheet according to a fourth embodiment, wherein FIG. 7A is a plan view and FIG. 7B is a side view. Both the upper convex portion 15 and the lower convex portion 16 provided on the thin metal plate 10C are formed in a bead shape. The metal sheet 10C is made of a material having the same linear expansion coefficient as the bus bar.

The upper protruding portion 15 has a T-shape at the center of the metal sheet 10C, comprising a top 15a parallel to the edge of the metal sheet 10C and a leg 15b extending from the middle of the top 15a to the edge. Four are formed corresponding to the edges. Although the tops 15a of the respective upper protrusions 15 are not connected to each other, the four tops 15a have a rectangular shape as a whole. Further, the tip of the leg portion 15b of each upper convex portion 15 is located at a bisecting point of each edge of the thin metal plate 10C.

The lower convex portion 16 is formed so as to overlap with the peripheral contour of the semiconductor chip 3 indicated by a virtual line in FIG.
The metal sheet 10C extends along the vicinity of each edge. The lower convex portion 16 is provided with two portions separated by a leg 15b of the upper convex portion 15 for each edge, and has a square shape surrounding the square shape of the top portion 15a of the upper convex portion 15 as a whole. The other configuration is the same as that of the third embodiment except that the metal sheet 10B is changed to the metal sheet 10C.

According to the present embodiment, since the lower protruding portion 16 is provided so as to overlap the peripheral contour of the semiconductor chip 3, the lower convex part 16 is provided on the peripheral contour of the semiconductor chip 3 as in the third embodiment. The thickness of the solder 4b is increased by the amount of protrusion of the lower convex portion 16, and the stress at the peripheral end of the semiconductor chip 3 is reduced. Further, since the upper convex portion 15 has a T-shape and its leg portion 15b extends to the edge of the thin metal plate 10C, it serves as a passage for voids (air bubbles) generated below the thin metal plate 10C, and becomes a joint. This has the effect of reducing voids remaining in the substrate.

FIG. 12 is a view showing a fifth embodiment in which the shape of the convex portion of the thin metal plate is further changed. (A) of the figure is a plan view, and (b) is a side view. Both the upper convex portion 17 and the lower convex portion 18 provided on the thin metal plate 10D are formed in a bead shape. The metal sheet 10D is made of a material having the same linear expansion coefficient as the bus bar. The upper convex portions 17 extend from the vicinity of the center of the thin metal plate 10D to the edges in a direction perpendicular to the edges, and are formed in four corresponding to the edges. The tip is located at the bisecting point of each edge.

The lower protruding portion 18 extends diagonally from each corner of the thin metal plate 10D, and the tip toward the center thereof is stopped outside the center of the upper protruding portion 17 from the center of the thin metal plate 10D. . Each of the center-side distal ends of the upper convex portion 17 and the lower convex portion 18 is located on the inner side (center side) of the peripheral contour of the semiconductor chip 3 indicated by a virtual line in FIG. As described above, the upper convex portion 17 and the lower convex portion 18 extend radially to the edges and corners as a whole. As a result, the void generated at the joint is
For example, it is possible to remove the solder effectively by performing vacuum evacuation while the soldering temperature is equal to or higher than the melting point of the solder. The lower protruding portion 18 overlaps a corner of the semiconductor chip 3. The other configuration is the same as that of the third embodiment except that the metal sheet 10B is changed to the metal sheet 10D.

According to the present embodiment, the second embodiment is different from the second embodiment in that a thin metal plate having the same linear expansion coefficient as that of the bus bar is arranged between the bus bar and the semiconductor chip, and that the thin metal plate has upper and lower convex portions. In addition to the same effect as described above, since the upper convex portion 17 and the lower convex portion 18 all extend radially to the edges and corners, the effect of reducing voids remaining at the joint is large. Further, since the lower protruding portion 18 overlaps the corner of the semiconductor chip 3 and the thickness of the solder between the semiconductor chip 3 and the thin metal plate increases at the corner of the semiconductor chip 3 where the stress is particularly concentrated, the stress is reduced. As a result, the influence of the stress on the semiconductor chip 3 is reduced.

In each embodiment, the material of the thin metal plate is the same as that of the bus bar 1. However, the present invention is not limited to this. For example, the coefficient of linear expansion of the bus bar is the same as or the same as that of the bus bar. As long as the material has a linear expansion coefficient, the material components can be changed as appropriate. In addition, the third and fourth
In the embodiment, the upper convex portion and the lower convex portion are each formed so as to draw a quadrangle, but other than that, a substantially circular shape can be drawn, and various modifications can be made to the planar shape.
In addition, although each embodiment shows an example in which the present invention is applied to a mounting unit of an inverter circuit, the present invention can be applied to various mounting units in which a semiconductor chip is joined to a metal electrode plate by soldering.

[Brief description of the drawings]

FIG. 1 is a top view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a perspective view showing a positional relationship of a bus bar in the embodiment.

FIG. 4 is a circuit diagram of one phase of an inverter to which the embodiment is applied.

FIG. 5 is an enlarged cross-sectional view showing a bonding portion of a semiconductor chip.

FIG. 6 is a diagram showing characteristics of a metal material and silicon.

FIG. 7 is a cross-sectional view of a joint showing a second embodiment.

FIG. 8 is a view showing details of a metal thin plate in the second embodiment.

FIG. 9 is a cross-sectional view of a joint showing a third embodiment.

FIG. 10 is a diagram showing details of a thin metal plate in a third embodiment.

FIG. 11 is a view showing a metal sheet according to a fourth embodiment.

FIG. 12 is a view showing a thin metal plate according to a fifth embodiment.

FIG. 13 is a diagram showing a conventional example.

[Explanation of symbols]

 1, 1a, 1b Bus bar (metal electrode plate) 1c Bus bar 2 Resin base 3, 3a, 3b Semiconductor chip 4a, 4b Solder (joining material) 5a, 5b, 9a, 9b Metal wire 6a, 6b Gate terminal 7 Heat dissipation sheet 8 Heat sink 10, 10A, 10B, 10C, 10D Metal sheet 11, 13, 15, 17 Upper convex part 12, 14, 16, 18 Lower convex part 15a Top part 15b Leg part 20 Joint part 100 Mounting unit

Claims (8)

[Claims] 1. A semiconductor mounting structure in which a semiconductor chip is mounted on a metal electrode plate, wherein between the semiconductor chip and the metal electrode plate, the thickness is smaller than the metal electrode plate and closer to or closer to the metal electrode plate than the semiconductor chip. A semiconductor mounting structure, wherein a metal thin plate having the same linear expansion coefficient as the metal electrode plate is arranged, and the metal electrode plate and the metal thin plate and the semiconductor chip and the metal thin plate are bonded with a bonding material. . 2. The metal thin plate has an upper convex portion protruding toward the semiconductor chip and a lower convex portion protruding toward the metal electrode plate, and a top of the upper convex portion is formed of a semiconductor. 2. The semiconductor mounting structure according to claim 1, wherein said lower convex portion is in contact with a chip, and said lower convex portion is in contact with a metal electrode plate. 3. The semiconductor mounting structure according to claim 2, wherein the upper convex portion and the lower convex portion are formed so as to be located inside a peripheral contour of the semiconductor chip. 4. A lower convex portion of the thin metal plate has a bead shape,
3. The semiconductor mounting structure according to claim 2, wherein the semiconductor chip is formed at a position overlapping on a peripheral contour line of the semiconductor chip, and the upper convex portion is formed inside the lower convex portion. 5. The semiconductor mounting structure according to claim 4, wherein the lower convex portion is continuous along a peripheral contour of the semiconductor chip so as to form a quadrangular planar shape. 6. The semiconductor mounting structure according to claim 4, wherein said upper convex portion includes a leg portion extending to an edge of said metal sheet. 7. An upper convex portion of the thin metal plate has a bead shape,
The corner of the metal sheet extends from inside the peripheral contour of the semiconductor chip to the edge of the metal sheet, the lower convex portion has a bead shape, and diagonally on the diagonal line of the metal sheet from the inside of the peripheral contour of the semiconductor chip. The semiconductor mounting structure according to claim 2, wherein the semiconductor mounting structure extends to at least one of the plurality of semiconductor devices. 8. The method according to claim 1, wherein the metal electrode plate is made of copper or aluminum or an alloy containing them, and the thin metal plate is made of the same metal material as the metal electrode plate. 8. The semiconductor mounting structure according to 5, 6, or 7.