JP2002305276A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat radiation properties in a semiconductor device. SOLUTION: A heat spreader 2, where a semiconductor chip 1 is packaged, is exposed from a sealing body 5, a joining means 9 is mounted to a portion where the exposed portion is overlapped to one portion of a heat radiation fin 10, and the heat radiation fin 10 is fixed detachably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device technology, and more particularly to a technology effective when applied to a heat dissipation technology of a semiconductor device.

[0002]

2. Description of the Related Art With the increase in power consumption of semiconductor devices, various types of semiconductor devices having a resin-sealed type package structure have been variously reduced in thermal resistance. The high heat dissipation type semiconductor device studied by the present inventors exposes a part of the heat spreader included in the package of the semiconductor device from the package, and solders the exposed portion to a conductor pattern of a wiring board for mounting the semiconductor device. The heat radiation path is set by joining with the above.

[0003] Regarding heat dissipation technology for semiconductor devices,
For example, Nikkei BP, published May 31, 1993, "Practical Course VLSI Packaging Technology (Lower)" p200-
This is described in detail on page 212.

[0004]

However, the present inventor has found that there are the following problems in the above heat radiation technology. In other words, in the technology that secures a heat dissipation path only by joining a part of the heat spreader to the conductor pattern of the wiring board by soldering or the like, the heat dissipation performance of the semiconductor device greatly depends on the heat dissipation performance of the wiring board, and further improvement of the heat dissipation performance is required. There is a problem that can not be addressed.

An object of the present invention is to provide a technique capable of improving the heat dissipation of a semiconductor device.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, according to the present invention, in the first heat radiator joined to the semiconductor chip, the exposed portion exposed from the sealing body and the second heat radiator outside the sealing body can be detachably attached by the fastening means. Are mechanically joined together.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the following embodiments, when necessary for convenience, the description will be made by dividing into a plurality of sections or embodiments, but unless otherwise specified, they are not related to each other. Instead, one has a relationship of some or all of the other modifications, details, supplementary explanations, and the like.

Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, amount, range, etc.), the number is particularly limited and is limited to a specific number in principle. Except in some cases, the number is not limited to the specific number, and may be more than or less than the specific number.

Further, in the following embodiments, the constituent elements (including the element steps, etc.) are not necessarily essential unless otherwise specified, and when it is deemed essential in principle. Needless to say, there is nothing.

Similarly, in the following embodiments, when referring to the shapes, positional relationships, and the like of the constituent elements, etc., unless otherwise specified, and unless otherwise apparently considered in principle, it is substantially the same. And those similar or similar to the shape or the like. This is the same for the above numerical values and ranges.

In all the drawings for describing the embodiment, parts having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) In this embodiment, a case where the present invention is applied to a semiconductor device having a QFP (Quad Flat Package) structure in which a power IC (Integrated circuit) is formed will be described.

FIG. 1 is a plan view of the semiconductor device, and FIG.
1 is a plan view of the semiconductor device shown in FIG. 1 from which a sealing body and a bonding wire are removed, FIG. 3 is a cross-sectional view taken along line AA in FIG. 1, and FIG. FIG. 5 is an enlarged plan view of the connecting portion of the fastening means in the first radiator of the semiconductor device of FIG. 1 and the like.

A semiconductor chip (hereinafter, simply referred to as a chip) 1 constituting the semiconductor device of the present embodiment is, for example, a small piece of silicon single crystal having a plane quadrangular shape as a substrate, and has a main surface (first surface) facing upward. And mounted on a heat spreader (first heat radiator) 2.

On the main surface of the chip 1, for example, a power MOS
-An FET circuit is formed. This power MOS F
The electrodes of the ET circuit are led out by a plurality of bonding pads (external terminals) arranged near the outer periphery of the main surface of the chip 1. One end of a bonding wire (hereinafter simply referred to as a wire) 3 is joined to the bonding pad. The wire 3 is made of, for example, gold (Au) or aluminum (Al), and the other end is joined to the lead 4. The lead 4 is made of, for example, copper (Cu).
A plurality of alloys or 42 alloys are arranged at predetermined intervals along the outer periphery of the chip 1 so as to surround the outer periphery (four sides).

The chip 1 and the wires 3 are covered with a sealing body 5 made of a plastic material such as a glass epoxy resin. The end of the lead 4 on the chip 1 side is covered with a sealing body 5, but the end separated from the chip 1 is exposed from the sealing body 5. The leads 4, so-called outer leads, exposed from the sealing body 5 are formed, for example, in a gull wing shape, and the leading end thereof is connected to a printed wiring board (wiring board) 6.
Land 6 formed on the first surface (mounting surface of the semiconductor device)
a and a solder material such as lead (Pb) -tin (Zn) solder or the like (see FIG. 3). The circuit of the semiconductor device is electrically connected to the wiring of the printed wiring board 6 by the connection between the lead 4 and the land 6a. Here, a state is illustrated in which the semiconductor device is mounted on the printed wiring board 6 such that the back surface of the chip 1 faces the first surface of the printed wiring board 6.

The printed wiring board 6 is provided with a four-layer wiring structure on an insulating substrate made of a plastic material such as a glass epoxy resin. On the first surface of the printed wiring board 6, in addition to the lands 6a, a conductor pattern 6b for mounting a chip and a wiring pattern are formed.
The four-layer wiring (including the land 6a and the conductor pattern 6b) of the printed wiring board 6 is made of, for example, copper or a copper alloy. Further, the printed wiring board 6 has a through hole 6 having a flat circular shape penetrating the first surface and the second surface of the back surface.
c is perforated. On the inner wall surface of the through hole 6c,
For example, a conductor film 6d made of copper or a copper alloy is coated. The conductive film 6d is connected to the wiring of the printed wiring board 6.

On the other hand, the back surface (second surface) of the chip 1
Is bonded to the heat spreader 2 via an adhesive 7 such as a solder material made of a lead (Pb) -tin (Zn) alloy or a silver (Ag) paste having a high adhesive strength.
The heat spreader 2 is made of a metal such as a copper (Cu) alloy or aluminum (Al). When a copper alloy is selected as the material of the heat spreader 2, since the heat conductivity of copper is higher than that of other metals, the heat dissipation of the heat generated in the chip 1 can be improved. Further, since the difference in the coefficient of thermal expansion with respect to the chip 1 is smaller than that of aluminum, cracks and the like of the chip 1 due to the thermal stress of the chip 1 can be suppressed or prevented. On the other hand, when aluminum is selected, although the heat dissipation is lower than that of the copper alloy, the weight of the semiconductor device can be reduced while maintaining a certain degree of heat dissipation. The entire surface or a part of the heat spreader 2 may be plated with a metal such as nickel or gold. Thereby, the corrosion resistance and the bonding property with other members can be improved.

The pattern of the heat spreader 2 has a planar square pattern portion 2a at the center thereof and a band-like pattern portion 2b projecting radially outward from the four corners of the pattern portion 2a (FIG. 1). 2). The planar dimension of the planar quadrangular pattern portion 2a is larger than the planar dimension of the chip 1, and the chip 1 is mounted at the center of the pattern portion 2a. The upper surface of the pattern portion 2a (that is, the surface on which the chip 1 is mounted) is covered with the sealing member 5, but the side and back surfaces thereof are exposed from the sealing member 5. The back surface of the heat spreader 2 is joined to the conductor pattern 6b on the first surface of the printed wiring board 6 via an adhesive 8 such as lead-tin solder.

In the strip-shaped pattern portion 2b of the heat spreader 2, a part of the upper surface at the base portion is covered with the sealing body 5, but the surface on the outer end side (namely, the upper surface, the side surface, and the rear surface). Is exposed from the sealing body 5. The corner of the tip of the pattern portion 2b exposed from the sealing body 5 is partially notched (see FIGS. 1, 2 and 5). The cutout area at the corner is a fastening means attachment area (hereinafter simply referred to as an attachment area) 2c for hooking the bolt 9a of the fastening means 9.

In the present embodiment, mounting regions 2c having the same shape are formed at the tips of the four pattern portions 2b of the heat spreader 2, and the fastening means 9 is mounted on the four mounting regions 2c. The four attachment areas 2c are located at substantially the same distance from the center of the chip 1,
Alternatively, they are dispersed and arranged in a well-balanced manner so as to be vertically and horizontally symmetrical with respect to the chip 1. If the mounting regions 2c are not arranged in a well-balanced manner, the thermal stress generated by the heat generated in the chip 1 may be unevenly applied to the chip 1, resulting in a crack in the chip 1. On the other hand, by arranging the mounting regions 2c in a well-balanced manner as described above, heat generated in the chip 1 can be transmitted to each of the four pattern portions 2b in substantially the same manner. 1
Since the thermal stress applied to the chip 1 can be made substantially uniform, cracks in the chip 1 can be suppressed or prevented. Also,
By arranging the mounting area 2c as described above,
Since the attachment of the fastening means 9 can be performed regularly, the workability of the attachment of the fastening means 9 can be improved, and the work time for the attachment can be reduced.

However, the shape of the mounting area 2c is
The present invention is not limited to the above, and various changes can be made. For example, it may be as shown in FIG. That is, in FIG. 6A, the attachment area 2c is the pattern portion 2
It is formed by a flat semi-elliptical notch extending from the side of b to the center. In FIG. 6B, the mounting region 2c is formed by a plane circular hole opened in the pattern portion 2b. Further, in FIG. 6C, the attachment area 2c is formed by a plane elliptical hole opened in the pattern portion 2b.

FIGS. 5 and 6 show the shape of the mounting area 2c.
In the case of (a) and (c), the mounting area 2c
In addition, since a certain margin in the plane dimensions can be provided, even if the plane position of the mounting area of the pattern portion 2b and the plane position of the through hole 6c of the printed wiring board 6 are slightly shifted, the margin is provided. The fastening means 9 can be attached. That is, the mounting area 2c
And the degree of freedom of the formation position of the through hole 6c can be improved. Therefore, the dimensional accuracy of the attachment region 2c of the pattern portion 2b and the accuracy of the formation position of the through hole 6c can be reduced, so that the workability of the heat spreader 2 and the printed wiring board 6 can be improved.

In the case of FIGS. 5 and 6A, the area of the heat spreader 2 can be reduced, and the mounting area of the semiconductor device can be reduced. As shown in FIGS. 6B and 6C, in the case of a type in which a hole is formed in the pattern portion 2b of the heat spreader 2, the area of the pattern portion 2b must be larger than the plane area of the hole. The mounting area of the semiconductor device including the above becomes large. This poses a problem when the electronic components mounted on the printed wiring board 6 are required to have a high density, and the pattern portion 2b cannot be made too large due to the relationship between adjacent electronic components. On the other hand, in the case of FIG. 5 and FIG. 6A, since the attachment area 2c is formed by cutting out a part of the pattern part 2b, it is necessary to make the pattern part 2b larger than the attachment area 2c. Because there is no
The above problems can be avoided. Therefore, when there is no margin in the area for attaching the fastening means 9, the type shown in FIGS. 5 and 6A is selected, and when there is a margin in the area for attaching the fastening means 9, FIG. It is also effective to select the types () and (c).

The fastening means 9 comprises a bolt 9a and a nut 9
b. The bolt 9a is connected to the heat spreader 2
And protrudes from the first surface of the printed wiring board 6 through the through hole 6c to the second surface via the pattern portion 2b. The bolt 9a has a nut 9
b is fitted and fixed. The bolt 9a and the nut 9b are made of, for example, copper or a copper alloy in consideration of heat dissipation. However, bolt 9a and nut 9b
Is not limited to this, and general constituent materials for bolts and nuts may be used. Thereby, cost can be reduced.

However, the fastening means 9 is not limited to the bolt 9a and the nut 9b but can be variously changed. For example, as shown in FIGS.
It is good. FIG. 7 is an enlarged plan view of a main part of the pattern portion 2b of the heat spreader 2, and FIG. 8 is an enlarged cross-sectional view of a main part of the semiconductor device. The insertion pin 9c is penetrated into the plane circular mounting area 2c opened in the pattern portion 2b of the heat spreader 2 and into the through hole 6c of the printed wiring board 6. And this insertion pin 9c
Are fixed by being formed such that the diameter of the upper end thereof is larger than the diameter of the mounting region 2c, and the diameter of the lower end of the insertion pin 9c is larger than the diameter of the through hole 6c. I have. The material of the insertion pin 9c may be the same as that of the bolt 9a and the nut 9b, but may be an insulating material such as high thermal conductive rubber. When this insertion pin 9c is used, the mounting time of the fastening means 9 can be greatly reduced as compared with the case where the bolt 9a and the nut 9b are used. Further, since the number of parts can be reduced, the cost of the semiconductor device can be reduced.

In the semiconductor device having such a structure, the heat generated on the main surface of the chip 1 is dissipated through, for example, the following route. First, the heat is dissipated outside through the wire 3 and the lead 4. Second, the heat is transmitted to the heat spreader 2 through the back surface of the chip 1 and is radiated to the outside. In this second heat radiation path, for example, there is the following heat radiation path (see the arrow in FIG. 4). First, the heat is spread through the surface of the heat spreader 2 exposed from the sealing body 5. Second, the heat is transmitted from the back surface of the heat spreader 2 to the conductor pattern 6 b and is radiated through the wiring of the printed wiring board 6. further,
Thirdly, in the present embodiment, the heat transmitted to the heat spreader 2 is transmitted to the fastening means 9 through the pattern portion 2b and is radiated through the surface thereof, and the heat transmitted from the fastening means 9 to the inside of the through hole 6c of the printed wiring board 6 It is transmitted to the wiring through the conductive film 6d and is radiated. As described above, in the present embodiment, the heat generated in the chip 1 can be dissipated through a large number of heat dissipation paths, so that the heat dissipation performance of the semiconductor device can be improved.

When the heat spreader 2 is joined to the printed circuit board 6 using only the adhesive 8 made of solder or the like, the semiconductor device cannot be fixed stably due to the fatigue failure of the adhesive 8, and the semiconductor device cannot be fixed. There is a case where the reliability in joining is reduced. On the other hand, in the present embodiment, since the heat spreader 2 is mechanically fixed to the printed wiring board 6 by the fastening means 9, even if the adhesive 8 is subjected to fatigue failure, the semiconductor device can be kept for a long period of time. The semiconductor device can be fixed stably over the entire region, and the reliability of the bonding of the semiconductor device can be improved. In the present embodiment, the semiconductor device is bonded to the printed wiring board 6 with the adhesive 8.
However, the adhesive 8 may be removed and the heat spreader 2 may be fixed to the printed wiring board 6 only by the fastening means 9. By doing so, fatigue fracture of the adhesive 8 can be avoided. Also, at this time, the thermal stress can be reduced by adjusting the amount of fastening of the fastening means 9, so that the reliability of the joining of the semiconductor device can be improved. Further, attachment and detachment of the semiconductor device can be relatively easily performed.

(Embodiment 2) The present embodiment describes a case where the heat spreader is set to a predetermined potential, and the other configuration is the same as that of Embodiment 1.

FIG. 9 is a cross-sectional view of a semiconductor device as an example. In this case, the back surface of the chip 1 is electrically connected to the heat spreader 2 through the adhesive 7. The heat spreader 2 is connected to the wiring of the printed wiring board 6 through the adhesive 8 and the conductor pattern 6b, and the wiring is electrically connected to, for example, a GND potential (reference potential). That is, chip 1
Has a structure to which a GND potential is supplied. The GND potential is set to, for example, 0 (zero) V. In the case of this structure, since the supply area of the GND potential can be increased, the stability of the GND potential can be improved. Therefore, a change in the GND potential due to an electromagnetic wave or the like can be suppressed or prevented, so that the occurrence of a malfunction of the semiconductor device due to the change in the GND potential can be suppressed or prevented.

FIG. 10 shows another example, and is a sectional view of a main part of a semiconductor device. In this case, the adhesive 7 uses an insulating material, and the back surface of the chip 1 and the heat spreader 2 are insulated. Here, the GN of chip 1
A D potential (reference potential) is drawn out by a bonding pad on the main surface of the chip 1 and is electrically connected to the heat spreader 2 through a wire 3a. The heat spreader 2 may be electrically connected to the GND potential through the conductor pattern 6b of the printed wiring board 6 in the same manner as described above, but here, the heat spreader 2 is connected to the through hole 6c via the fastening means 9.
And a printed wiring board 6
It is configured to be electrically connected to the GND potential through the internal wiring. In the case of this structure, a large GND potential supply area can be secured, and the GND potential can be obtained from any part of the chip 1 depending on the arrangement of the wires 3a, so that the stability of the GND potential can be improved. . Therefore, GN caused by electromagnetic waves
Since the fluctuation of the D potential can be suppressed or prevented, its GND
It is possible to suppress or prevent occurrence of a malfunction of the semiconductor device due to a potential change.

Here, the case where the heat spreader 2 is set to the reference potential has been described. However, the present invention is not limited to this. For example, the heat spreader 2 may be set to the power supply potential on the higher potential side. Also in this case, the stability of the power supply potential can be improved, so that the operation reliability of the semiconductor device can be improved.

(Embodiment 3) The present embodiment describes a modification of the mounting region of the heat spreader, and other configurations are the same as those of the first and second embodiments.

FIG. 11 shows an example of such a structure, and shows a structure intended to allow a positioning error between the mounting area 2c of the heat spreader 2 and the through hole of the printed wiring board 6. Here, the two mounting areas 2c on the left side of FIG. 11 are formed by plane circular holes,
FIG. 11 illustrates a case where the two mounting areas 2c on the right side of FIG. 11 are formed by plane-oval holes. When attaching this semiconductor device to the printed wiring board 6, first, FIG.
After the fastening means 9 is attached to the two attachment areas 2c on the left side of FIG. 11, the fastening means 9 is attached to the two attachment areas 2c on the right side of FIG. According to this structure, when the fastening means 9 is mounted on the two mounting areas 2c on the right side in FIG. 11, the two mounting areas 2c on the left side and the through holes of the printed wiring board 6 are slightly displaced from each other. Can compensate for the deviation. Here, the left mounting area 2c is illustrated as an elliptical shape extending in the horizontal direction of FIG. 11, but the shape of the mounting area 2c is not limited to this and can be variously changed. It is preferable to extend the hole of the attachment area 2c in a direction in which the displacement easily occurs.

(Embodiment 4) This embodiment is directed to a modification of the attachment region of the heat spreader, and other configurations are the same as those of the first and second embodiments.

FIG. 12 shows an example of this, and shows a structure in which the attachment area 2c of the heat spreader 2 has a function as a mark. Here, the planar shape of the mounting region 2c at the upper left of FIG. 12 is circular, and the planar shape of the other mounting region 2c is elliptical. This is achieved by making one of the plurality of mounting areas 2c different from the shape of the other mounting areas 2c.
It has a function as a mark. The worker sees the plane circular attachment area 2 c and mounts the semiconductor device on the printed wiring board 6. By providing the mounting area 2c serving as a mark, the semiconductor device can be accurately mounted on the printed wiring board without making a mistake in the mounting direction of the semiconductor device. Therefore, it is possible to prevent a problem caused by a wrong mounting of the semiconductor device. In addition, since the removal of the semiconductor device due to the mounting error can be eliminated, the working efficiency can be improved. Here, the case where the mounting region 2c at the upper left of FIG. 12 is formed into a plane circular shape is exemplified, but the purpose of the present embodiment is that the mounting region 2c only has to function as a mark, and is limited to the plane circular shape. Various changes can be made instead of the above.

When mounting the semiconductor device of the present embodiment on a printed wiring board, first, the fastening means 9 is attached to the upper left attachment area 2c, and then the fastening means 9 is attached to the other attachment area 2c. Is preferred. Thus, the same effect as in the third embodiment can be obtained.

(Embodiment 5) This embodiment is directed to a modification of the mounting region of the heat spreader. The other structure is the same as that of the first and second embodiments.

FIG. 13 shows an example of such a case, in which the mounting area 2c of the heat spreader 2 is arranged so that the semiconductor device cannot be mounted in a state where the mounting direction is wrong.

Here, the lower right mounting area 2 in FIG.
c is a circular plane, and the other mounting area 2c
Is an elliptical shape. Therefore, FIG.
The mounting area 2c at the lower right of 3 has a function as a mark as in the fourth embodiment. Also, the arrangement position of the attachment area 2c at the lower right in FIG. 13 is arranged so as to be different from the arrangement position of the other attachment areas 2c. That is, the other attachment area 2c is arranged symmetrically in the vertical and horizontal directions with respect to the center of the chip 1, but the attachment area 2c at the lower right in FIG. 13 is arranged so as to be asymmetric. This makes it possible to prevent the semiconductor device from being mounted in the wrong direction. Therefore, the same effect as in the fourth embodiment can be obtained. The purpose of the present embodiment is to form the mounting region 2c on the heat spreader 2 so that the mounting direction of the semiconductor device is not mistaken, and the shape and arrangement of the mounting region 2c are not limited to those described above. Various changes are possible.

The mounting method of the semiconductor device according to the present embodiment is similar to that of the third and fourth embodiments, except that the fastening means 9 is mounted on the flat circular mounting area 2c, and then the fastening means 9 is mounted on the other mounting area 2c. Is preferably attached. Thus, similarly to the third and fourth embodiments, misalignment between the mounting region 2c and the through hole 6c can be allowed. However, the dimensions and arrangement of the mounting area 2c are designed so that misalignment in a state where the mounting direction of the semiconductor device is wrong is not allowed.

(Embodiment 6) This embodiment describes a case where a heat radiating fin (second heat radiator) is mounted on a semiconductor device, and other than that is the same as Embodiments 1 to 5. .

FIGS. 14 to 17 show the semiconductor device of the present embodiment. 14 is a perspective view of the semiconductor device of the present embodiment, FIG. 15 is a plan view of the semiconductor device of FIG. 14, FIG. 16 is a cross-sectional view taken along line CC of FIG. 15, and FIG. The main part enlarged plan view which shows 10a is each shown.

The radiating fin 10 is made of a metal having high thermal conductivity such as copper, copper alloy or aluminum, and can be detached by the fastening means 9 with its fin portion 10b facing upward. It is attached to a semiconductor device. Here, the radiation fins 10 are provided above the main surface of the chip 1. The back surface of the radiation fin 10 is joined to the sealing body 5 directly or via a radiation sheet. When a heat radiating sheet is interposed between the heat radiating fin 10 and the sealing body 5, the adhesion between the heat radiating fin 10 and the sealing body 5 can be improved, so that the heat radiating characteristics of the semiconductor device can be improved. Can be. In the present embodiment, the tightness of the fastening means 9 can be adjusted to improve the adhesion between the radiating fin 10 and the sealing body 5. The heat dissipation characteristics of the semiconductor device can be improved without interposing a heat dissipation sheet in the semiconductor device. Therefore, the cost can be reduced by eliminating the heat radiation sheet. Here, the case where the fin portion 10b is plate-shaped is illustrated, but the present invention is not limited to this, and various changes can be made. For example, the fin portion 10b may have a columnar shape.

At the tip of the pattern portion 10c extending radially from the four corners of the radiation fin 10, an attachment area 10a for attaching the fastening means 9 is formed.
Here, as shown in FIG.
Are formed by plane circular holes. The bolt 9a of the fastening means 9 is attached to the mounting area 10 of the radiating fin 10.
a, It penetrates through the mounting area 2c of the heat spreader 2 and the through hole 6c of the printed wiring board 6, and is detachably fixed to a tip portion thereof by a nut 9b fitted thereto.

However, the mounting area 1 of the radiation fin 10
The shape of Oa is not limited to the above, but can be variously changed. For example, the shape shown in FIG. 18 may be used.
In FIG. 18A, the attachment region 10a is formed by a cutout having a plane semi-elliptical shape extending from the side of the pattern portion 10c to the center. In FIG. 18B, the mounting region 10a is formed by a plane elliptical hole opened in the pattern portion 10c. further,
In FIG. 18C, the mounting area 10a is formed by cutting out a corner of the pattern portion 10c. This is because the heat spreader 2 described with reference to FIGS.
Is the same as That is, FIGS.
In this case, misalignment of the radiation fins 10 (misalignment with respect to the mounting area 2c of the heat spreader 2 and the through hole 6c of the printed wiring board 6) can be tolerated. Also in this case, as described in the third to fifth embodiments, the shape and arrangement of the attachment region 10b may be changed for each of the four corner pattern portions 10c. In this case, the third to fifth embodiments are described.
Similarly to the above, misalignment of the radiation fins 10 can be tolerated.
Also, when attaching the radiating fins 10, there is a case where it is necessary to attach the radiating fins 10 in a directional manner due to the flow direction of air cooling or the like or the convenience of the design of the entire device incorporating the printed wiring board 6. In this case, the function as the mark or the mounting area 10a can be prevented from being mistakenly attached by preventing it from being attached by mistake.

In the semiconductor device having such a structure, the following heat dissipation path is formed in addition to the heat dissipation path described in the first embodiment. The first is a path through which heat generated on the main surface of the chip 1 is transmitted to the radiation fins 10 via the sealing body 5 and dissipated. The second is a path in which the heat generated on the main surface of the chip 1 is transmitted to the heat spreader 2 through the back surface of the chip 1, and then transmitted to the heat dissipating fins 10 via the fastening means 9 and dissipated (see FIG. 16). As described above, in the present embodiment, since the number of heat radiation paths can be increased, the heat radiation characteristics can be further improved as compared with the case of the first embodiment. Therefore, it is possible to easily implement a total heat radiation design such that the heat dissipation is not reduced even when the peripheral functions are incorporated into one chip or a plurality of chips are mounted. Further, the radiation fins 10 can be replaced with various ones according to the radiation conditions of the semiconductor device. Therefore, the degree of freedom in heat radiation design can be improved.

(Embodiment 7) This embodiment relates to FIG.
As shown in FIG. 20 and FIG. 20, the case where the mounting state of the semiconductor device is reversed with respect to the above-described first to sixth embodiments will be described.

In this embodiment, the main surface of the chip 1 is
It comes to face the first surface of the printed wiring board 6. Therefore, the sealing body 5 is in contact with the first surface of the printed wiring board 6. A heat dissipating fin 10 is detachably connected to the back surface of the chip 1 via a heat spreader 2 by fastening means 9.

According to the present embodiment, since the heat radiating path between the heat spreader 2 and the heat radiating fin 10 is short and the contact area is large, the heat radiating characteristics are further improved as compared with the first to sixth embodiments. It becomes possible. Also in this case, a heat radiation sheet may be interposed between the heat spreader 2 and the heat radiation fins 10.

(Embodiment 8) In this embodiment, as shown in FIG. 21, the radiation fin 10 is detachably attached to the heat spreader 2 by a screw (fastening means) 9d. The screw 9d is made of, for example, copper, a copper alloy, aluminum, or the like. The end of the screw 9d does not penetrate the heat spreader 2 and is screwed to a position halfway in the thickness direction of the heat spreader 2. That is, the screw 9
d is not connected to the printed wiring board 6. Therefore, the printed wiring board 6 is not provided with a through hole for attaching the fastening means. Otherwise,
This is the same as the first to seventh embodiments.

According to the present embodiment, the first embodiment
The following effects can be obtained in addition to the effects obtained in Nos. To 7. That is, there is no need to provide a through hole for attaching the fastening means to the printed wiring board 6, so that the wiring area can be increased accordingly. Further, the degree of freedom in wiring arrangement on the printed wiring board can be improved. Therefore, the easiness of designing the printed wiring board can be improved.

(Embodiment 9) In Embodiments 1 to 8, the case where four heat spreader mounting areas are provided has been described. However, the present invention is not limited to this, and various modifications can be made.

FIG. 22 is a partially broken plan view of an example of the semiconductor device according to the present embodiment. In FIG.
A semiconductor device having a flat package structure is illustrated. The lead 4 protrudes from the long side (two sides) of the sealing body 5. The heat spreader 2 is formed in a planar rectangular shape, and both ends are projected (exposed) from both ends in the longitudinal direction of the sealing body 5. The heat spreader 2
The mounting area 2c is formed in each of the exposed areas at both ends. That is, here, the attachment area 2c is provided at two places. However, the formation positions of the mounting regions 2c at both ends of the heat spreader 2 are the same as those in the first embodiment.
Similarly to 7, they are arranged in a well-balanced manner so as to be symmetrical about the chip 1.

In the present embodiment, the mounting area 2c is
The heat spreader 2 is formed by cutting out the center portions of both sides of the heat spreader 2 into a plane semi-elliptical shape. The semiconductor device is mounted on the printed wiring board by fitting the bolt 9a of the fastening means 9 into the mounting area 2c. However, the shape of the mounting area 2c is not limited to this shape, and can be variously changed.
The shape described above may be used.

According to the ninth embodiment, the same effects as those of the first to eighth embodiments can be obtained.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the gist of the invention. Needless to say,

For example, a structure in which the lead and the chip are connected by a bump electrode may be employed.

The present invention can also be applied to various package structures, for example, an SOP (Small Outline Package).

In the above description, the case where the invention made by the present inventor is mainly applied to a semiconductor device having a power MOS-FET circuit, which is the field of application as the background, has been described. However, the present invention is not limited to this. ,
For example, DRAM (Dynamic Random Access Memory), S
RAM (Static Random Access Memory) or flash memory (EEPROM; Electric Erasable Progra)
The present invention can also be applied to a semiconductor device having a memory circuit such as an mmable read only memory (MMM) or a semiconductor device in which a memory circuit and a logic circuit are provided on the same semiconductor substrate.

[0064]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

That is, the first bonded to the semiconductor chip
The heat radiation performance of the semiconductor device is improved by mechanically joining the exposed portion of the heat radiator exposed from the sealing body and the second heat radiator outside the sealing body in a detachable manner by fastening means. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a plan view of the semiconductor device shown in FIG. 1 from which a sealing body is removed.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a sectional view taken along line BB of FIG. 1;

FIG. 5 is an enlarged plan view of a fastening means coupling portion in the first radiator of the semiconductor device of FIG. 1 and the like;

6 (a) to 6 (c) are enlarged plan views of a main part of a first radiator showing a modified example of the fastening means mounting region of FIG.

FIG. 7 is an enlarged plan view of a main part of a first radiator of a semiconductor device according to another embodiment of the present invention;

8 is an enlarged cross-sectional view of a main part of the semiconductor device of the same embodiment as FIG. 7;

FIG. 9 is a cross-sectional view of a semiconductor device according to another embodiment of the present invention.

FIG. 10 is a sectional view of a main part of a semiconductor device according to another embodiment of the present invention;

FIG. 11 is a plan view of a semiconductor device according to another embodiment of the present invention.

FIG. 12 is a plan view of a semiconductor device according to another embodiment of the present invention.

FIG. 13 is a plan view of a semiconductor device according to another embodiment of the present invention.

FIG. 14 is a perspective view of a semiconductor device according to another embodiment of the present invention.

FIG. 15 is a plan view of the semiconductor device of FIG. 14;

FIG. 16 is a sectional view taken along line CC of FIG. 15;

17 is an enlarged plan view of a main part of a radiation fin in the semiconductor device of FIG. 15;

FIGS. 18 (a) to (c) are enlarged plan views of a main part of a modified example of a mounting area of a radiation fin.

FIG. 19 is a cross-sectional view of a semiconductor device according to another embodiment of the present invention.

FIG. 20 is a sectional view of the same semiconductor device as FIG. 19;

FIG. 21 is a sectional view of a semiconductor device according to another embodiment of the present invention;

FIG. 22 is a partially broken plan view of a semiconductor device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Heat spreader (1st heat radiator) 2a Pattern part 2b Pattern part 2c Fastening means attachment area 3 Bonding wire 4 Lead 5 Sealing body 6 Printed wiring board (wiring board) 6a Land 6b Conductive pattern 6c Through hole 6d Conductive film Reference Signs List 7 adhesive 8 adhesive 9 fastening means 9a bolt (fastening means) 9b nut (fastening means) 9c insertion pin (fastening means) 9d screw (fastening means) 10 radiating fin (second radiator) 10a fastening area attaching area 10b fin Part 10c pattern part

Continued on the front page F term (reference) 5F036 AA01 BA04 BB05 BC03 BC09 BE01

Claims (5)

[Claims] A semiconductor chip, a lead connected to a terminal on a first surface of the semiconductor chip, a first radiator joined to a second surface of the semiconductor chip opposite to the first surface;
A sealing body covering the whole of the semiconductor chip, a part of the lead, and a part of the first radiator; and a second radiator exposed from the sealing body. A semiconductor device, wherein an exposed portion from the sealing body and a part of the second radiator are mechanically joined in a detachable manner by fastening means. 2. A semiconductor chip, a lead connected to a terminal on a first surface of the semiconductor chip, and a first radiator joined to a second surface of the semiconductor chip opposite to the first surface.
A sealing body covering the whole of the semiconductor chip, a part of the lead and a part of the first radiator, and a second radiator exposed from the sealing body; A part of the lead to be bonded to the conductor pattern of the wiring board; a part of the first heat radiator exposed from the sealing body is bonded to the conductor pattern of the wiring board; Exposed part from the stop,
A semiconductor device, wherein a part of the second heat radiator is mechanically joined in a detachable state by a fastening means, and a part of the fastening means is joined to the wiring board. 3. A semiconductor chip, a lead connected to a terminal on a first surface of the semiconductor chip, and a first heat radiator joined to a second surface of the semiconductor chip opposite to the first surface.
A sealing body covering the whole of the semiconductor chip, a part of the lead and a part of the first radiator, and a second radiator exposed from the sealing body; A part of the lead to be bonded to the conductor pattern of the wiring board; a part of the first heat radiator exposed from the sealing body is bonded to the conductor pattern of the wiring board; A portion exposed from the stopper and a part of the second heat radiator are mechanically joined in a detachable state by a plurality of fastening means; a part of the fastening means is joined to the wiring board; A semiconductor device, wherein the plurality of fastening means in a heat radiator are dispersedly arranged so as to be symmetrical to each other. 4. A semiconductor chip, a lead connected to a terminal on a first surface of the semiconductor chip, and a first radiator joined to a second surface of the semiconductor chip opposite to the first surface.
A sealing body covering the whole of the semiconductor chip, a part of the lead and a part of the first radiator, and a second radiator exposed from the sealing body; A part of the lead to be bonded to the conductor pattern of the wiring board; a part of the first heat radiator exposed from the sealing body is bonded to the conductor pattern of the wiring board; Exposed part from the stop,
A part of the second radiator is mechanically joined to the wiring board in a detachable state by fastening means; a part of the fastening means is joined to the wiring board; A semiconductor device electrically connected to a potential. 5. A semiconductor chip, a lead connected to a terminal on a first surface of the semiconductor chip, a radiator joined to a second surface of the semiconductor chip opposite to the first surface, and the semiconductor chip. And a sealing body covering a part of the lead and a part of the heat radiator, and a portion of the heat radiator exposed from the sealing body and a wiring board are mechanically joined by fastening means. A semiconductor device characterized by the following.