JP2003243584A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device in which the film thickness of silicon grease on the composition plane of a base plate and a radiating fin can be made uniform when coupling the base plate and the radiating fin by bolts and reliability can be improved by suppressing stress applied to an insulating substrate in the semiconductor device in which the base plate and the radiating fin are coupled by interposing heat conductive grease between the both. <P>SOLUTION: On the rear side of the base plate or on the counter side of the radiating fin, a plurality of recesses are formed while being located inside positions of a plurality of first mounting holes on the base plate or a plurality of second mounting holes on the radiating fin proximately to the plurality of first mounting holes or the plurality of second mounting holes and when coupling the base plate and the radiating fin, the heat conductive grease near the inside of the positions of the plurality of first mounting holes and the plurality of second mounting holes is made to escape to the plurality of recesses. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which a heat conductive grease is interposed between a base plate and a heat radiating fin to bond them to each other.

[0002]

2. Description of the Related Art FIG. 31 shows, for example, Japanese Patent Laid-Open No. 2000-228.
FIG. 4 is a cross-sectional view showing a conventional semiconductor device disclosed in Japanese Patent Publication No. 490, 490, in which 1 is an insulating substrate on which a chip 2 is mounted on a front surface side 1 a, 3 is a case for housing this insulating substrate 1, and 4 is the above-mentioned. The back side 1b of the insulating substrate 1 is joined to the front side 4a, and the one end 3a of the case 3 is joined with an adhesive (not shown) and screws (not shown), and the plurality of mounting holes are provided on the outer peripheral side. 4b is formed on the base plate, 6 is joined to the back surface side 4c of the base plate 4, and radiating fins are formed with a plurality of mounting screw holes 6a facing the plurality of mounting holes 4b. A plurality of bolts that pass through the hole 4b and are screwed into the plurality of mounting screw holes 6a to form a screw member that connects the base plate 4 and the heat radiation fin 6.

In this structure, one end 3a of the case 3 is joined to the base plate 4 to which the insulating substrate 1 is joined to the front surface side 4a with an adhesive (not shown) and a screw (not shown). To be done. Further, the back side 4c of the base plate 4
The heat radiation fin 6 is joined to. Then, the plurality of bolts 7 penetrate the plurality of mounting holes 4b and are screwed into the plurality of mounting screw holes 6a, and the base plate 4 is coupled to the heat radiation fins 6. In this way, the base plate 4 and the radiation fins 6 are joined, and the heat of the base plate 4 is radiated to the radiation fins 6. By the way, on the back surface side 4c of the base plate 4 and the facing surface side 6b of the heat radiation fin 6 facing the back surface side 4c, unevenness is present in a normal processing method, so that the heat radiation effect tends to be reduced. Therefore, as shown in FIG. 32, the back surface side 4c of the base plate 4 is
Silicon grease 5 as a heat conductive grease on the entire surface
Is applied, and the heat radiation fins 6 are joined through the silicone grease 5. Therefore, the heat of the base plate 4 is effectively radiated to the heat radiation fins 6.

[0004]

The conventional semiconductor device is
The silicon grease 5 is applied to the entire rear surface 4c of the base plate 4, the heat radiation fins 6 are aligned with each other, and the base plate 4 and the heat radiation fins 6 are coupled via the plurality of bolts 7. When the bolt 7 is screwed, the silicon grease 5 inside the joint surface between the base plate 4 and the radiation fin 6 is pushed out to the surroundings. However, as shown in FIG. 33, on the back surface side 4c of the base plate 4, the silicon grease 5a existing inside the positions of the plurality of mounting holes 4b is closed by the bolt 7 when pushed out to the surroundings. The silicon grease 5a is stopped and stays inside the positions of the plurality of mounting holes 4b, and the silicon grease 5a in that portion has a larger film thickness than other portions. When the bolt 7 is screwed in such a state, the base plate 4 is warped, stress is applied to the insulating substrate 1 joined to the base plate 4, and the stress causes the stress.
There has been a problem that cracks may occur in the insulating substrate 1 after a long period of time.

The present invention has been made to solve the above problems, and when the bolt 7 is screwed,
An object of the present invention is to provide a semiconductor device in which the film thickness of the silicon grease 5 on the joint surface between the base plate 4 and the radiation fins 6 can be made uniform, the stress applied to the insulating substrate 1 can be suppressed, and the reliability can be improved.

[0006]

According to a first aspect of the present invention, there is provided a semiconductor device, wherein a plurality of first mounting holes of the base plate or the heat radiation are provided on a back surface side of a base plate or an opposing surface side of a heat radiation fin. A plurality of second mounting holes of the fin, each of which is located inward of each of the plurality of second mounting holes and is provided with a plurality of recesses adjacent to the plurality of first mounting holes or the plurality of second mounting holes; When the heat dissipating fins are joined together, the heat conductive grease in the vicinity of the inside of the positions of the plurality of first mounting holes and the plurality of second mounting holes is allowed to escape into the plurality of recesses. is there.

Further, in the semiconductor device according to the second aspect of the present invention, the recess is a recess formed on the back surface side of the base plate or on the facing surface side of the heat radiation fin, and a communication portion that connects this recess to the outside. It is composed of.

Further, in the semiconductor device according to the third invention, the recess is composed of a recess formed on the back surface side of the base plate or on the facing surface side of the heat radiation fin, and the end portion of this recess portion is outward. It is one that has been opened.

Further, in the semiconductor device according to the fourth aspect of the present invention, the concave portion is a concave portion formed on the back surface side of the base plate or the facing surface side of the heat radiation fin, and the concave portion is formed continuously with the concave portion. And a penetrating portion penetrating in one direction.

Further, in the semiconductor device according to the fifth aspect of the present invention, the concave portion is a concave portion formed on the back surface side of the base plate or on the opposite surface side of the heat radiation fin, and the concave portion of the heat radiation fin facing the concave portion. It is composed of a communicating portion which is formed on the facing surface side or the back surface side of the base plate and which communicates the recessed portion to the outside.

Further, in the semiconductor device according to the sixth aspect of the present invention, the concave portion continuously communicates with each of the plurality of second mounting holes of the heat radiation fin in the extending direction thereof, and the tip positions of the plurality of screw members are provided. It is built up to a deeper position.

Further, in the semiconductor device according to the seventh invention, a plurality of first mounting holes of the base plate or a plurality of the radiation fins are provided on the back surface side of the base plate or the facing surface side of the radiation fins. Located inside the respective positions of the second mounting holes and formed respectively near the plurality of first mounting holes or the plurality of second mounting holes, the back surface side of the base plate and the heat radiation side. A plurality of penetrating portions that make the joint surface of the fin facing the facing surface side communicate with the outside are provided, and the plurality of first mounting holes and the plurality of second mounting holes are provided when the base plate and the heat radiation fin are coupled. The heat conductive grease in the vicinity of the inner position of the mounting hole is released to the plurality of penetrating portions.

Further, in the semiconductor device according to the eighth aspect of the present invention, the base plate is formed so as to be closer to the inside position than the respective positions of the plurality of first mounting holes on the back surface side of the base plate. While forming a plurality of penetrating portions penetrating from the side to the front surface side, the case is formed with a communicating portion that communicates the plurality of penetrating portions to the outside, and when the base plate and the heat radiation fin are coupled, The thermally conductive grease near the positions inside the plurality of first mounting holes is allowed to escape to the plurality of through portions.

Further, in the semiconductor device according to the ninth aspect of the present invention, the semiconductor device according to the ninth aspect is provided on the back surface side of the base plate or the opposing surface side of the heat radiation fins, and the plurality of first mounting holes of the base plate or the plurality of heat radiation fins. The base plate and the heat radiating fin are provided so as to be concentrically connected to the second mounting hole and have a plurality of recesses having a diameter larger than that of the plurality of first mounting holes or the plurality of second mounting holes. At the time of coupling, the heat conductive grease in the vicinity of the inner side of the positions of the plurality of first mounting holes is allowed to escape into the plurality of recesses.

Furthermore, in the semiconductor device according to the tenth aspect of the invention, as the heat conductive grease, silicon grease is used.
While applying in a thickness range of 0 μm to 200 μm,
The joint between the back surface side of the base plate and the opposing surface side of the heat radiation fin is formed so that the flatness is in the range of -100 μm to +150 μm or the surface finish is within 12 s.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. The first embodiment of the present invention will be described with reference to FIGS. 1 is a sectional view of the semiconductor device, FIG. 2 is a partially enlarged sectional view of FIG.
FIG. 3 is a bottom view of the base plate of FIG. 1. In the figure, 1 is an insulating substrate on which a chip 2 is mounted on the front surface side 1a, 3 is a case for accommodating the insulating substrate 1, and 4 is a back surface side 1b of the insulating substrate 1 whose front surface side 4a is bonded and Case 3
Is a base plate which is joined to one end 3a of the base material with an adhesive material (not shown) and screws (not shown), and has the plurality of mounting holes 4b formed on the outer peripheral side thereof. Silicon grease 5 is applied as. Reference numeral 4d is a recess formed of a groove formed inside the plurality of mounting holes 4b. Reference numeral 6 denotes a heat radiating fin in which the rear surface side 4c of the base plate 4 is joined via silicon grease 5 and a plurality of mounting screw holes 6a facing the plurality of mounting holes 4b are formed, and 7 denotes the plurality of mounting holes 4b. Through the base plate 4 and screwed into the plurality of mounting screw holes 6a.
And a plurality of bolts that constitute a screw member that couples the heat radiation fins 6 with each other. Reference numeral 8 is a gel injected into the case 3, 9 is a resin injected onto the gel 8, and 10 is a lid for sealing the inside of the case 3.

In this structure, one end 3a of the case 3 is joined to the base plate 4 having the insulating substrate 1 bonded to the one surface side 4a by an adhesive (not shown) and a screw (not shown). To be done. Further, as shown in FIG. 3, the silicon grease 5 is applied on the entire back surface 4c of the base plate 4.
Is applied, and the radiation fin 6 is joined. Then
The plurality of bolts 7 penetrate the plurality of mounting holes 4b and are screwed into the plurality of mounting screw holes 6a, and the base plate 4 is coupled to the heat radiation fins 6. By the way, the silicon grease 5 is applied to the entire surface of the back surface 4c of the base plate 4, the heat radiation fins 6 are aligned, and the base plate 4 and the heat radiation fins 6 are coupled to each other through the plurality of bolts 7. However, when the bolt 7 is screwed, the silicon grease 5a on the inner side of the joint surface between the base plate 4 and the heat radiation fin 6 is pushed out to the periphery. Here, as shown in FIG. 3, since the recesses 4d are formed inside the plurality of mounting holes 4b, the silicon grease 5a existing inside the plurality of mounting holes 4b is located. Will flow into the recess 4d. Therefore, the silicone grease 5a is replaced by the bolt 7
Is no longer blocked, and the film thickness of the silicon grease 5 becomes uniform over the entire surface. Therefore, when the bolt 7 is screwed, the warp of the base plate 4 is prevented, the stress on the insulating substrate 1 joined to the base plate 4 is suppressed, and the insulating substrate 1 is cracked. Is prevented from occurring. On the other hand, since the entire surface of the base plate 4 and the radiating fins 6 are joined uniformly via the silicon grease 5, the heat of the base plate 4 is effectively radiated to the radiating fins 6. .

In the first embodiment, the concave portion 4d is described as a groove, but the silicon grease 5a is used.
However, the shape is not particularly limited. Further, although the base plate 4 has the concave portion 4d, the concave portion 6c may be provided on the facing surface side 6b of the heat radiation fin 6 facing the back surface side 4c of the base plate 4, as shown in FIG. Further, although the description has been given of the case where the silicon grease 5 is applied to the entire back surface 4c of the base plate 4, the radiating fins 6 facing the back surface 4c of the base plate 4 are described.
It may be applied to the facing surface side 6b. Furthermore, it may be provided on both the base plate 4 and the radiation fins 6.

Embodiment 2. The second embodiment of the present invention will be described with reference to FIG. 6 is a plan view of the heat radiation fin. In the figure, 6c is a concave portion provided on the side 6b of the radiating fin 6 facing the base plate 4 inside the positions of the plurality of mounting holes 6a of the radiating fin 6, and its end 6d is indicated by an alternate long and short dash line. It is open outward from the position of the base plate 4 shown by. In this configuration, bolt 7
When screwing, the silicon grease 5a on the inner side of the joint surface between the base plate 4 and the heat radiation fins 6 is pushed out to the surroundings, but the recesses are formed inside the plurality of mounting holes 6a. 6c is formed, the silicon grease 5a existing inside the plurality of mounting holes 6a tends to flow into the recess 6c. Here, since the end portion 6d of the recess 6c is open outward from the position of the base plate 4, the inside of the recess 6c is maintained at the atmospheric pressure, and the silicon grease 5 reaches the recess 6c. It will flow easily. Therefore, the film thickness of the silicon grease 5 is quickly made uniform between the base plate 4 and the radiation fins 6, and the workability is improved.

Embodiment 3. The third embodiment of the present invention will be described with reference to FIGS. 7 and 8. 7 is a side view of the base plate, and FIG. 8 is a bottom view thereof. In the figure, 4 d is a recess formed of a groove formed inside the plurality of mounting holes 4 b of the base plate 4, and one end 4 f thereof is open to the outer periphery of the base plate 4. In this configuration, since the thin portion 4g of the base plate 4 at the position of the recess 4d extends to the outer periphery of the base plate 4, the thin portion 4g has elasticity, and when the bolt 7 is screwed in. The warp of the base plate 4 is suppressed, and the stress on the insulating substrate 1 bonded to the base plate 4 is further relieved. In the third embodiment of the invention, the recess 4d is provided on the base plate 4 side. However, the same effect can be obtained by providing the recess on the surface of the heat dissipation fin that faces the base plate 4. In addition,
As shown in FIG. 9, in the structure in which both ends of the recess 4d are opened to the outer periphery of the base plate 4, a thin portion (not shown) surrounds the periphery of the plurality of mounting holes 4b, so that the elastic effect of the thin portion is improved. Due to the synergistic effect of this elastic effect and the homogenization of the silicon grease 5, the concentration of stress on the insulating substrate 1 bonded to the base plate 4 can be suppressed.

Fourth Embodiment The fourth embodiment of the present invention will be described with reference to FIGS. 10 is a bottom view of the base plate, and FIG. 11 is a sectional view taken along line XI-XI of FIG. In the figure, 4h is a penetrating portion which is continuous with the recess 4d and which penetrates the base plate 4. In this configuration, since the penetrating portion 4h that is continuous with the recess 4d is separated from the opening surface side of the recess 4d, the silicon grease 5a existing inside the plurality of mounting holes 4b is located in the recess 4d.
Even if it flows into the entire surface, the penetration portion 4h is not blocked, so that the inside pressure of the recess 4d can be maintained at the atmospheric pressure, the silicon grease 5 smoothly flows into the recess 4d, and the film thickness of the silicon grease 5 is made uniform over the entire surface. it can. In addition, in the fourth embodiment of the present invention, the description has been given of the case where the concave portion 4d and the penetrating portion 4h continuous with the concave portion 4d are provided on the base plate 4 side.
The same effect can be obtained by providing a concave portion and a penetrating portion continuous with the concave portion on the side of the radiation fin.

Embodiment 5. The fifth embodiment of the present invention will be described with reference to FIGS. 12 is a bottom view of the base plate, and FIG. 13 is a plan view of the heat radiation fin. In the figure, 4d is a recess formed by a groove formed inside the plurality of mounting holes 4b of the base plate 4, and 6c is this recess 4d.
At least a part of the base plate 4 is a concave portion that faces each other and that is located inside the positions of the plurality of mounting holes 6a in the radiating fin 6, and the end portion 6d is the base plate 4 shown by a chain line.
It is open to the outside of the position. In this configuration, the silicon grease 5a existing inside the plurality of mounting holes 4b flows into both the concave portion 4d on the base plate 4 side and the concave portion 6c on the heat radiation fin 6 side. Can be easily made uniform over the entire surface.

In the fifth embodiment of the present invention, the base plate 4
Although the concave portion 4d is provided on the side and the end 6d of the concave portion 6c of the heat radiation fin 6 facing the concave portion 4d is open to the outside, as shown in FIG. 14, a plurality of mounting holes for the base plate 4 are provided. A concave portion 4d formed of a groove is provided inside 4b,
The end 4f of the recess 4d is opened to the outer periphery of the base plate 4, and the position of the plurality of mounting holes 6a in the heat radiation fin 6 is set so as to face at least a part of the recess 4d as shown in FIG. The same effect can be obtained with the configuration in which the recess 6c is provided at the inner position.

Sixth Embodiment The sixth embodiment of the present invention will be described with reference to FIGS. 16 is a bottom view of the base plate, and FIG. 17 is a plan view of the heat radiation fins. In the figure, 4d is a recess formed by a groove formed inside the plurality of mounting holes 4b of the base plate 4, and 6e is this recess 4d.
At least a part of each is a penetrating portion which faces each other and penetrates a position inside the plurality of mounting holes 6a in the heat dissipation fin 6. In this configuration, one is the concave portion 4d and the other is the penetrating portion 6.
It is a combination of e and the penetrating portion 6e is processed before assembling the both. Therefore, in the configuration in which the silicon grease 5 is applied, the penetrating portion 6e is processed and provided, and
In the case where the coating is not applied, the processing of the penetrating portion 6e may be omitted, and the same radiation fin 6 can be shared by these two. In the sixth embodiment of the present invention,
The case where the recess 4d is provided on the side of the base plate 4 and the penetrating portion 6e is provided on the side of the heat radiation fin 6 has been described. Produce an effect.

Embodiment 7. The seventh embodiment of the present invention will be described with reference to FIGS. 18 is a sectional view of the semiconductor device, and FIG. 19 is a plan view of the radiation fin. In the figure, 6f is a position inside the plurality of second mounting holes 6a of the heat radiation fin 6, and the plurality of mounting holes 6a are
Is a recess communicating with the plurality of mounting holes 6a continuously in the extending direction of the plurality of mounting holes 6a, and is provided in the plurality of mounting holes 6a up to a position H2 deeper than the tip positions H1 of the plurality of bolts 7.
In this configuration, since the depth of the recess 6f is provided up to a position H2 deeper than the tip positions H1 of the plurality of bolts 7,
Since the inside of the recess 6f is maintained in the atmosphere, the silicon grease 5 can easily flow into the recess 6f, and since the recess 6f communicates with the plurality of mounting holes 6a, the silicon grease 5 also adheres to the bolt 7. However, the silicone grease 5 has an effect of preventing the bolt 7 from loosening.

Embodiment 8. Embodiment 8 of the present invention will be described with reference to FIG. 20. FIG. 20 is a bottom view of the base plate. In the figure, 4h is a plurality of penetrating portions formed inside the plurality of mounting holes 4b of the base plate 4.
With this configuration, for example, an appropriate number is formed by cutting, etc., which facilitates processing. Further, since the respective penetrating portions 4h are individually communicated with the atmosphere, the silicon grease 5 can be easily introduced, and the film thickness of the silicon grease 5 can be easily made uniform. Although the through-hole 4h is formed in the base plate 4 in the above configuration, the same effect can be obtained by forming the through-hole 6e at a position inside the plurality of second mounting holes 6a of the heat radiation fin 6 as shown in FIG. Play.

Ninth Embodiment The ninth embodiment of the present invention will be described with reference to FIGS. 22 is a partial cross-sectional view of the semiconductor device, FIG. 23 is a partial bottom view of the base plate, and FIG. 24 is a partial bottom view of the case. In the figure,
Reference numeral 3b denotes a plurality of mounting holes penetrating the case 3 corresponding to the plurality of mounting holes 4b of the base plate 4, and 3c is formed inside the plurality of mounting holes 3b, and a plurality of penetrating portions penetrating the case 3. 4h are a plurality of mounting holes 4 of the base plate 4
The plurality of penetrating portions 4h formed at the inner position of b are formed at the inner positions of the plurality of mounting holes 4b of the base plate 4,
It is a plurality of penetrating portions that communicate with the penetrating portion 3c. In this configuration, the case 3, the base plate 4, and the heat radiation fin 6 are attached to the bolt 7
Even if the structure is joined by the
Therefore, the film thickness of the silicon grease 5 can be easily made uniform. In the configuration, the case 3 is provided with the penetrating portion 3c so that the penetrating portion 4
25 and 26, the case 3 has a recess 3 that communicates with the through portion 4h of the base 4 as shown in FIGS.
It is also possible to have a structure in which d is provided and the end portion 3e is opened at the outer circumference of the case 3.

Embodiment 10. Embodiment 1 of the present invention
0 will be described with reference to FIGS. 27 and 28. 27 is a partial cross-sectional view of the semiconductor device, and FIG. 28 is a partial rear view of the base plate. In the figure, reference numeral 4d designates a plurality of recesses which are provided on the other surface side 4c of the base plate 4 and are located substantially concentrically with the plurality of mounting holes 4b of the base plate 4, and have a larger diameter than the plurality of mounting holes 4b. The end portion 4f opens to the outer periphery of the base plate 4 to communicate the plurality of recesses 4b with the outside air. In this configuration, the concave portion 4d is located on the outer periphery of the bolt 7, and when the base plate 4 and the radiation fin 6 are coupled, the silicon grease 5 near the inside of the plurality of mounting holes 4b is bolted. Before it is blocked by 7, it can be released into the plurality of recesses 4b, and the film thickness of the silicon grease 5 can be made extremely uniform.

Eleventh Embodiment Embodiment 1 of the present invention
1 will be described with reference to FIGS. 29 and 30. 29 is a partial cross-sectional view of the semiconductor device, and FIG. 30 is a partial plan view of the heat radiation fin. In the figure, reference numeral 6c designates a plurality of recesses which are provided in the heat radiation fin 6 and are substantially concentric with the plurality of mounting holes 6a of the heat radiation fin 6, and have a larger diameter than the plurality of mounting holes 6a, and the end portions 6d thereof. Opens outward from the outer peripheral position of the base plate 4 to communicate the plurality of recesses 6c with the outside air. In this configuration, since the recess 6c is provided in the heat dissipation fin 6 which is larger than the base plate 4, the size of the recess 6c can be set arbitrarily. In the tenth and eleventh embodiments, the ends 4f or 6d of the plurality of recesses 4b or the plurality of recesses 6c communicate with the outside air, but the ends 4f or 6d are not necessarily open to the outside air. You don't have to.

Twelfth Embodiment Embodiment 1 of the present invention
2, as shown in FIG. 1, as the heat conductive grease applied to the entire back surface 4c of the base plate 4 or the facing surface side 6b of the heat radiation fin 6 facing the back surface 4c of the base plate 4, Silicon grease 5 is 100 μm to 20
It is evenly applied in a thickness range of 0 μm. Further, the joint surface between the back surface side 4c of the base plate 4 and the facing surface side 6b of the heat dissipation fin 6 is configured to have a flatness in the range of -100 μm to +150 μm or a surface finish of 12 s or less. In this configuration, the silicon grease 5 is 100 μm to 200 μm.
Since the thickness is provided in the range of μm, corrosion of the contact surface between the base plate 4 and the radiation fin 6 is prevented. Also,
The flatness of the joint surface between the base plate 4 and the radiation fin 6 is -10.
Range of 0μm to + 150μm or surface finish is 12s
Since it is configured within, the contact area can be effectively secured.

[0031]

Since the present invention is configured as described above, it has the following effects.

On the back surface side of the base plate or the facing surface side of the heat radiation fins, inside the respective positions of the plurality of first mounting holes of the base plate or the plurality of second mounting holes of the heat radiation fins. And having a plurality of recesses adjacent to the plurality of first mounting holes or the plurality of second mounting holes,
When the base plate and the heat radiation fin are coupled, the heat conductive grease near the inner side of the positions of the plurality of first mounting holes and the plurality of second mounting holes escapes into the plurality of recesses. Since the heat conductive grease is not blocked by the screw member, the film thickness of the heat conductive grease can be made uniform over the entire surface, and when the screw member is screwed, the base plate Warp is prevented, and stress on the insulating substrate bonded to the base plate is suppressed,
Generation of cracks in the insulating substrate is prevented. Further, since the entire surface of the base plate and the heat radiation fins are evenly bonded via the heat conductive grease, the contact thermal resistance of the base plate can be minimized and the heat radiation effect of the heat radiation fins can be improved. effective.

Since the recess is composed of a recess formed on the back surface side of the base plate or on the opposing surface side of the heat radiation fin, and a communication portion communicating this recess to the outside, the inside of the recess is large. Maintained at atmospheric pressure, the heat conductive grease will easily flow into the recess, and the film thickness of the heat conductive grease can be quickly made uniform between the base plate and the heat radiation fins. It has the effect of improving the sex.

The concave portion is formed by a concave portion formed on the back surface side of the base plate or the facing surface side of the heat radiation fin, and the end portion of the concave portion is opened outward, and the base plate is the concave portion. Since the thin part at the position is formed up to the outer periphery of the base plate, the thin part has elasticity, and when the screw member is screwed, the base plate is prevented from warping and is joined to the base plate. The stress applied to the insulating substrate is further alleviated by the synergistic effect of the elastic effect of the thin portion and the uniformization of the film thickness of the heat conductive grease.

The recess is composed of a recess formed on the back surface side of the base plate or on the opposing surface side of the heat radiation fin, and a penetrating portion formed continuously with the recess and penetrating outward. Therefore, the penetrating portion continuous to the recess is separated from the opening surface side of the recess, and even if the thermally conductive grease flows into the entire surface of the recess, the penetrating portion is not blocked, so that the inside of the recess is large. There is an effect that the atmospheric pressure can be maintained, the heat conductive grease can smoothly flow into the recess, and the film thickness of the silicon grease can be made uniform over the entire surface.

The concave portion is formed on the back surface side of the base plate or on the facing surface side of the heat radiation fins, and on the facing surface side of the heat radiation fins facing the hollow portion or on the back surface side of the base plate. Since it is formed by the communication part that communicates the recessed part to the outside, the heat conductive grease will flow into both the recessed part on the base plate side and the recessed part on the heat radiation fin side, and the heat transfer The effect is that the film thickness can be easily made uniform over the entire surface of the organic grease.

Since the concave portion is continuously communicated with each of the plurality of second mounting holes of the heat radiation fin in the extending direction thereof and is provided side by side to a position deeper than the tip positions of the plurality of screw members, Since the inside of the recess is maintained in the atmosphere, the heat-conducting grease can easily flow into the above-mentioned recess, and the heat-conducting grease also adheres to the screw member and acts as a loosening stopper.

On the back surface side of the base plate or the facing surface side of the heat radiation fins, inside the respective positions of the plurality of first mounting holes of the base plate or the plurality of second mounting holes of the heat radiation fins. Are formed in proximity to the plurality of first mounting holes or the plurality of second mounting holes, respectively, and the joint surface between the back surface side of the base plate and the facing surface side of the heat radiation fin is outward. A plurality of penetrating portions that communicate with each other, and when the base plate and the heat radiation fins are coupled to each other, the plurality of first portions are connected to each other.
Since the thermal conductive grease near the positions inside the mounting holes and the plurality of second mounting holes is allowed to escape to the plurality of through portions, the appropriate number of through portions can be formed by cutting or the like. There is an effect that processing becomes easy.

A plurality of penetrating portions which are respectively formed closer to inner positions than the respective positions of the plurality of first mounting holes on the back surface of the base plate and penetrate the base plate from the back surface side to the front surface side. At the same time as forming, the case is formed with a communicating portion that communicates the plurality of through portions to the outside, and when connecting the base plate and the heat radiation fin, the connecting portion is more than the position of the plurality of first mounting holes. Since the thermal conductive grease near the inner position is allowed to escape to the multiple through-holes, even if the case, the base plate and the heat radiation fin are connected by the screw member, the thermal conductive grease can be smoothly passed through the through-holes. And the film thickness of the heat conductive grease can be easily made uniform.

It is provided on the back surface side of the base plate or on the opposing surface side of the heat radiation fins, and is substantially concentrically connected to the plurality of first mounting holes of the base plate or the plurality of second mounting holes of the heat radiation fins. A plurality of recesses having a larger diameter than the plurality of first mounting holes or the plurality of second mounting holes, and the plurality of first mountings when coupling the base plate and the heat radiation fins Since the heat conductive grease in the vicinity of the inner side of the hole is allowed to escape to the plurality of recesses, the recesses are located on the outer periphery of the screw member, and the base plate and the heat radiation fin are coupled to each other. When the plurality of first
Before the heat conductive grease in the vicinity of the position of the mounting hole is released to the plurality of recesses before being blocked by the screw member, there is an effect that the film thickness can be made extremely easy to be uniform.

Since silicon grease is applied as the heat conductive grease in a film thickness range of 100 μm to 200 μm, the above-mentioned silicon grease prevents corrosion of the contact surface between the base plate and the heat radiation fins, and it can be used for a long period of time. As a result, it is possible to maintain the heat radiation effect for a long period of time because the aging is prevented, and the flatness of the joint between the back surface side of the base plate and the opposing surface side of the heat radiation fin is -100 μm.
Since the surface finish is formed within the range of up to +150 μm or within 12 seconds, the contact area can be effectively secured, the contact thermal resistance can be minimized, and the heat dissipation effect can be maximized.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device showing a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the semiconductor device showing the first embodiment of the present invention.

FIG. 3 is a bottom view of the base plate showing the first embodiment of the present invention.

FIG. 4 is a partial bottom view of a base plate showing another embodiment of the first embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a semiconductor device showing another embodiment of the first embodiment of the present invention.

FIG. 6 is a plan view of a radiation fin showing a second embodiment of the present invention.

FIG. 7 is a side view of a base plate showing a third embodiment of the present invention.

FIG. 8 is a bottom view of the base plate showing the third embodiment of the present invention.

FIG. 9 is a partial bottom view of a base plate showing another embodiment of the third embodiment of the present invention.

FIG. 10 is a partial bottom view of the base plate showing the fourth embodiment of the present invention.

FIG. 11 is a partial cross-sectional view taken along line XI-XI of the base plate showing the fourth embodiment of the present invention.

FIG. 12 is a partial bottom view of the base plate showing the fifth embodiment of the present invention.

FIG. 13 is a partial plan view of a heat dissipation fin showing a fifth embodiment of the present invention.

FIG. 14 is a partial bottom view of a base plate showing another embodiment of the fifth embodiment of the present invention.

FIG. 15 is a partial plan view of a radiation fin showing another embodiment of the fifth embodiment of the present invention.

FIG. 16 is a partial bottom view of the base plate showing the sixth embodiment of the present invention.

FIG. 17 is a partial plan view of a heat radiation fin showing a sixth embodiment of the present invention.

FIG. 18 is a partial cross-sectional view of a semiconductor device showing a seventh embodiment of the present invention.

FIG. 19 is a partial plan view of a heat radiation fin showing a seventh embodiment of the present invention.

FIG. 20 is a partial bottom view of the base plate showing the eighth embodiment of the present invention.

FIG. 21 is a partial plan view of a heat radiation fin showing another embodiment of the eighth embodiment of the present invention.

FIG. 22 is a partial cross-sectional view of a semiconductor device showing a ninth embodiment of the present invention.

FIG. 23 is a partial bottom view of the base plate showing the ninth embodiment of the present invention.

FIG. 24 is a partial bottom view of the case showing the ninth embodiment of the present invention.

FIG. 25 is a partial cross-sectional view of a semiconductor device showing another embodiment of the ninth embodiment of the present invention.

FIG. 26 is a partial bottom view of a case showing another embodiment of the ninth embodiment of the present invention.

FIG. 27 is a partial cross-sectional view of the semiconductor device showing the tenth embodiment of the present invention.

FIG. 28 is a partial bottom view of the base plate showing the tenth embodiment of the present invention.

FIG. 29 is a partial cross-sectional view of a semiconductor device showing an eleventh embodiment of the present invention.

FIG. 30 is a partial plan view of a heat dissipation fin showing an eleventh embodiment of the present invention.

FIG. 31 is a cross-sectional view of a conventional semiconductor device.

FIG. 32 is a cross-sectional view of a conventional semiconductor device.

FIG. 33 is a bottom view of a base plate of a conventional semiconductor device.

[Explanation of symbols]

1 Insulating substrate, 1a Surface side, 2 chips, 3 cases, 3c, 4h, 6e Penetration part, 3d, 4d, 6c, 6
f Recesses, 3e, 4f, 6d Ends, 4 Base plates, 4
b Mounting hole, 4c Back side, 5 Silicon grease,
6 radiating fins, 6a mounting screw holes, 6b facing surface side, 7 bolts.

Claims (10)

[Claims] 1. A base plate on which an insulating substrate on which chips are mounted is bonded to the front surface side and a plurality of first mounting holes are formed on the periphery, and the base plate is bonded to the front surface side, and the insulating substrate is placed inside. A case, a heat dissipation fin joined to the back surface side of the base plate and having a plurality of second mounting holes facing the plurality of first mounting holes, a back surface side of the base plate or the base plate. The heat conductive grease applied to the facing surface side of the heat radiation fin facing the back surface side, and the plurality of first mounting holes and the plurality of second mounting holes, and the base plate. In a semiconductor device having a plurality of screw members for coupling with the heat radiation fins,
Located on the back surface side of the base plate or on the facing surface side of the heat dissipation fins and located inside the respective positions of the plurality of first mounting holes or the plurality of second mounting holes,
Positions of the plurality of first mounting holes when the base plate and the heat radiation fins are coupled to each other, the recesses being provided in proximity to the plurality of first mounting holes or the plurality of second mounting holes. A semiconductor device characterized in that the heat conductive grease near the inner position is allowed to escape to the plurality of recesses. 2. The recess is composed of a recess formed on the back surface side of the base plate or on the facing surface side of the heat radiation fins, and a communication portion communicating the recess with the outside. The semiconductor device according to claim 1. 3. The recess is composed of a recess formed on the back surface side of the base plate or on the opposing surface side of the heat radiation fin, and the end of this recess is opened outward. The semiconductor device according to claim 1. 4. The recess is composed of a recessed portion formed on the back surface side of the base plate or on the opposing surface side of the heat radiation fin, and a penetrating portion formed continuously with the recessed portion and penetrating outward. The semiconductor device according to claim 1, wherein: 5. The recessed portion is a recess formed on the back surface side of the base plate or the facing surface side of the heat radiation fin, and the facing surface side of the heat radiation fin facing the recessed portion, or the back surface of the base plate. 2. The semiconductor device according to claim 1, wherein the semiconductor device is formed of a communication portion that is formed on a side and communicates the recessed portion to the outside. 6. The recess is continuously communicated with each of the plurality of second mounting holes of the heat radiation fin in the extending direction thereof, and is provided side by side to a position deeper than the tip positions of the plurality of screw members. The semiconductor device according to claim 1, wherein: 7. An insulating substrate on which a chip is mounted is joined to the front surface side and a plurality of first mounting holes are formed on the periphery of the base plate. A case, a heat dissipation fin joined to the back surface side of the base plate and having a plurality of second mounting holes facing the plurality of first mounting holes, a back surface side of the base plate or the base plate. The heat conductive grease applied to the facing surface side of the heat radiation fin facing the back surface side, and the plurality of first mounting holes and the plurality of second mounting holes, and the base plate. In a semiconductor device having a plurality of screw members for coupling with the heat radiation fins,
Formed on the back surface side of the base plate, or on the opposite surface side of the heat dissipation fins, closer to inner positions than the respective positions of the plurality of first mounting holes or the plurality of second mounting holes, A plurality of penetrating portions that communicates outwardly the joint surface between the back surface side of the base plate and the facing surface side of the heat radiation fins are provided, and when the base plate and the heat radiation fins are coupled, the plurality of 1. A semiconductor device characterized in that the thermally conductive grease near the position inside the mounting hole of No. 1 is allowed to escape to the plurality of penetrating portions. 8. A base plate on which an insulating substrate on which chips are mounted is bonded to a front surface side and a plurality of first mounting holes are formed around the base plate, and the plurality of first mounting holes on the front surface side of the base plate. A plurality of third mounting holes facing each other, which are joined to the front surface side of the base plate and accommodate the insulating substrate inside, and the rear surface side of the base plate which is joined to the case. A radiating fin having a plurality of second mounting holes facing the mounting hole, a heat conductive grease applied to the back surface side of the base plate or the facing surface side of the radiating fin facing the back surface side of the base plate. , And the plurality of first mounting holes, and the plurality of second mounting holes,
In a semiconductor device including a plurality of screw members that are inserted into the plurality of third mounting holes and couple the base plate, the case, and the heat radiation fins, the plurality of first members on the back surface side of the base plate are provided. A plurality of penetrating portions that are formed closer to inner positions than the respective positions of the mounting holes, and that penetrate the base plate from the back surface side to the front surface side, When the base plate and the heat radiation fins are connected to each other, the heat conductive grease near the inner positions of the plurality of first mounting holes is removed from the heat conductive grease. A semiconductor device characterized in that it escapes into a plurality of penetrations. 9. An insulating substrate on which a chip is mounted is bonded to a front surface side, and a base plate having a plurality of first mounting holes formed around the base plate is bonded to the front surface side of the base plate. A case, a heat dissipation fin joined to the back surface side of the base plate and having a plurality of second mounting holes facing the plurality of first mounting holes, a back surface side of the base plate or the base plate. The heat conductive grease applied to the facing surface side of the heat radiation fin facing the back surface side, and the plurality of first mounting holes and the plurality of second mounting holes, and the base plate. In a semiconductor device having a plurality of screw members for coupling with the heat radiation fins,
It is provided on the back surface side of the base plate, or on the opposite surface side of the heat radiation fins, and is arranged substantially concentrically with the plurality of first mounting holes or the plurality of second mounting holes. A mounting hole or a plurality of recesses having a diameter larger than that of the plurality of second mounting holes is provided, and when the base plate and the heat radiation fin are coupled, the vicinity of the inner side of the positions of the plurality of first mounting holes 2. A semiconductor device characterized in that the heat conductive grease is allowed to escape into the plurality of recesses. 10. The heat conductive grease is silicon grease applied in a thickness range of 100 μm to 200 μm, and a flatness of a joint surface between the back surface side of the base plate and the facing surface side of the heat radiation fin is −100 μm. The semiconductor device according to any one of claims 1 to 9, characterized in that the surface finish is formed within a range of from +150 µm or within 12 seconds.