JP2000114442A - Package for electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a package for an electronic part by which adhesion between a metal plate for radiation and a radiating fin is improved and thermal resistance between a semiconductor device and the radiating fin is reduced. SOLUTION: A metal plate 10 for radiation comprises a copper-molybdenum plate 11 on the upper and lower sides of which a copper plated films 12 and 13 are formed, respective. Mounting parts 90 for mounting a radiating fin 60 are provided at both ends of the metal plate 10 for radiation. A clearance d is formed between the mounting parts 90 and the radiating fin 60. In this way, by mounting the radiating fin 60 on the metal plate 10 for radiation, the adhesion between the radiating fin adhering part 61 and the radiating fin 60 is improved. Accordingly, when a semiconductor device 30 is placed and fixed on a semiconductor device placing part 31, the thermal resistance between the semiconductor device 30 and the radiating fin 60 can be reduced. As a consequence, the heat generated during the operation of the semiconductor device 30 can be successfully dissipated outside and the semiconductor device 30 can be operated normally over the long term.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package for electronic components and a method for manufacturing the same.

[0002]

2. Description of the Related Art In semiconductor devices, Si chips and Ga
Electronic components such as a semiconductor element such as an As chip and a chip capacitor are mounted on an electronic component mounting portion provided in an electronic component package and are put to practical use. Ceramics such as alumina are excellent in heat resistance, durability, thermal conductivity, etc.
It is suitable as a material for the main body of the electronic component package, and ceramic electronic component packages are currently in active use.

[0003] In order to reduce the package size, increase the mounting density on a mounting board, and improve the electrical characteristics of the ceramic electronic component package, a plurality of green sheets are generally laminated and fired to insulate. A ceramic package body as a frame member is manufactured.

Further, in the case of a semiconductor module such as a power module which generates a large amount of heat from a semiconductor element, the semiconductor device may not operate normally due to heat generation if only the semiconductor element is mounted by a normal method. Therefore, as a package for an electronic component that satisfactorily dissipates heat generated during operation of a semiconductor element into the atmosphere, for example, a ceramic package having a heat-dissipating metal plate made of a metal having excellent heat conductivity is known. I have. Further, as a countermeasure for suppressing the temperature rise of the semiconductor element, a method of attaching a heat radiating fin to a heat radiating metal plate and removing heat of the semiconductor element by natural air cooling or forced air cooling by a fan is most widely adopted.

[0005]

The technology for forming a heat-dissipating metal plate used in a ceramic package according to the prior art described above is, for example, such that the coefficient of thermal expansion is close to the coefficient of thermal expansion of the ceramic package body and the coefficient of thermal conductivity is low. About 200W
A composite material having a material of about / mK and comprising a porous sintered body of tungsten or molybdenum impregnated with molten copper is known.

Aluminum or an aluminum alloy is generally used as a heat dissipating fin because of its light weight and economy, and copper or a copper alloy is used because of its good thermal conductivity. In some cases.

However, when the ceramic package body is joined to the upper surface of the heat-dissipating metal plate by brazing using a brazing material such as silver brazing, a difference in the coefficient of thermal expansion between the heat-dissipating metal plate and the ceramic package body is caused. Thermal stress may occur, and the brazing strength between the metal plate for heat dissipation and the ceramic package body may be reduced. further,
When the heat dissipating metal plate is warped and the heat dissipating fins are attached to the lower surface of the heat dissipating metal plate, the degree of adhesion between the heat dissipating metal plate and the heat dissipating fins is reduced. There is a problem that the thermal resistance between them increases.

When the thermal resistance between the semiconductor element and the heat radiating fins increases, it is difficult to completely dissipate the heat generated during operation of the semiconductor element to the outside via the heat radiating metal plate and the heat radiating fins. . Therefore, there has been a problem that a semiconductor element becomes high in temperature due to heat generated during operation of the semiconductor element, and the semiconductor element is physically destroyed or a characteristic of the semiconductor element undergoes a thermal change, thereby causing a malfunction of the semiconductor element. .

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has improved the degree of adhesion between a heat dissipating metal plate and a heat dissipating fin, thereby improving the thermal resistance between the semiconductor element and the heat dissipating fin. It is an object of the present invention to provide an electronic component package that reduces the number of electronic components.

[0010]

According to the electronic component package of the present invention, a contact portion is provided on the lower surface of the metal plate for heat radiation so as to be in close contact with the fin for heat radiation. A mounting portion having a gap between the heat radiation fin and the heat radiation fin is provided on the side. Therefore, when the insulating frame member is joined to the upper surface of the metal plate for heat dissipation, thermal stress occurs due to a difference in the coefficient of thermal expansion between the metal plate for heat dissipation and the insulating frame member. Even if it occurs, the degree of adhesion between the contact portion and the heat radiation fin is improved by attaching the heat radiation fin to the metal plate for heat radiation. Therefore, the thermal resistance between the semiconductor element and the radiating fins can be easily reduced, and the heat generated during the operation of the semiconductor element can be satisfactorily dissipated to the outside so that the semiconductor element can operate normally and stably for a long time. Can be done.

In this case, when the end of the metal plate for heat radiation is warped vertically upward, and the end of the metal plate for heat radiation is warped vertically downward, it is referred to as a convex warp. The gap between the mounting portion and the heat radiating fin effectively works. Hereinafter, the reason will be described.

In general, the radiating fin is fixed to the radiating metal plate using a dedicated member such as a screw or a clip.
For this reason, when a gap is not formed between the mounting portion and the radiating fin in the case of convex warpage, when the radiating fin is mounted on the radiating metal plate, the radiating metal corresponding to a portion immediately below the semiconductor element is provided. A gap may be formed between the plate, that is, the contact portion and the heat dissipation fin, and the degree of adhesion between the contact portion and the heat dissipation fin may be reduced, thereby increasing the thermal resistance between the semiconductor element and the heat dissipation fin. However, if a gap is formed between the mounting part and the radiating fin, even when the fin is attached to the radiating metal plate, even if it is convexly warped, the tight contact between the contact part and the radiating fin will occur. The degree improves. Therefore, the gap between the mounting portion and the heat dissipating fin is important.

According to the electronic component package of the present invention, the heat-dissipating metal plate is made of a metal material selected from the group consisting of molybdenum, copper-molybdenum, and copper-tungsten. A copper plating film formed on one or both surfaces of the copper sprayed film, any copper film selected from copper printed and fired film, or a copper plate joined by brazing to one or both surfaces of a metal plate Have. Therefore, by using a metal plate made of any metal material selected from molybdenum, copper-molybdenum, and copper-tungsten having an appropriate coefficient of thermal expansion, heat radiation having an appropriate coefficient of thermal expansion and a high thermal conductivity is provided. Metal plate can be obtained.

Forming a copper film selected from a copper plating film, a copper sprayed film, and a copper printed and fired film on a metal plate;
Or by joining a copper plate by brazing to a metal plate,
Compared to the one in which the copper plate is integrally joined to the metal plate by rolling, the thickness of the metal plate and copper film does not vary,
The heat-dissipating metal plate has a predetermined uniform thickness. Therefore, since the coefficient of thermal expansion of the heat dissipating metal plate does not partially differ, for example, the heat dissipating metal plate and the insulating frame member such as ceramics are brazed using a brazing material such as silver brazing, and When the semiconductor element is mounted on the plate, the deformation of the metal plate for heat radiation is small, the metal plate for heat radiation and the insulator can be firmly joined, and the semiconductor element is firmly fixed on the metal plate for heat radiation. Can be.

A heat-dissipating metal plate formed by forming a copper film on both surfaces of a metal plate or bonding a copper plate to both surfaces of the metal plate by brazing is formed between the metal plate and the copper film or between the metal plate and the copper plate. Since the thermal stress generated due to the difference in thermal expansion between the two is canceled out on both surfaces of the metal plate, the metal plate for heat radiation can always be made flat. Therefore, when the semiconductor element is mounted on the metal plate for heat radiation, the semiconductor element can be firmly fixed on the metal plate for heat radiation.

When the semiconductor element is mounted on the heat-dissipating metal plate, the thermal conductivity of the heat-dissipating metal plate is higher than the value of the entire heat-dissipating metal plate in the upper layer of the heat-dissipating metal plate. Is important, a copper film may be formed on only one surface of the metal plate corresponding to the portion directly below the semiconductor element, or the copper plate may be joined to only one surface of the metal plate by brazing. The copper plating method, thermal spraying method, or printing method can be performed by a known method, and is not particularly limited.

According to the electronic component package according to the third aspect of the present invention, the copper film or the copper plate is formed or joined to one or both surfaces of the metal plate except for the mounting portion.
The thickness of the copper film or the copper plate is equal to the gap between the mounting portion and the heat radiating fin. For this reason, the metal plate for heat radiation can be easily manufactured, and the gap between the mounting portion and the heat radiation fin can be easily formed. Therefore, the degree of adhesion between the contact portion and the heat radiation fin can be easily improved, and the thermal resistance between the semiconductor element and the heat radiation fin can be easily reduced.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a surface mount type ceramic semiconductor package.
This will be described with reference to FIG.

As shown in FIGS. 1 and 2, a ceramic semiconductor package 100 includes a heat-dissipating metal plate 10,
Package body 20 made of alumina, lead frame 50
And radiating fins 60 and the like.

The heat-dissipating metal plate 10 has a package body joining portion 81 to which the package body 20 is joined on its upper surface, and the semiconductor element 30 is mounted and fixed substantially at the center of the package body joining portion 81. The semiconductor element mounting portion 31 is provided. The semiconductor element 30 is mounted and fixed on the semiconductor element mounting portion 31 using an adhesive such as glass, resin, or brazing material.

The heat-dissipating metal plate 10 has a heat-dissipating fin contact portion 61 to which the heat-dissipating fins 60 are attached on the lower surface thereof and which are in close contact with the heat-dissipating fins 60. At both ends of the metal plate 10 for heat radiation, mounting portions 90 for mounting the fins 60 for heat radiation are provided. A groove portion 91 is formed between the upper surface of the mounting portion 90 and the package body joining portion 81, and a groove portion 92 is formed between the lower surface of the mounting portion 90 and the heat radiation fin contact portion 61. The notch 7 is provided in the mounting portion 90 so that the mounting portion 90 can be fixed using the screw 70.
1 is formed.

The heat-dissipating metal plate 10 has copper plating films 12 and 13 on both upper and lower surfaces of a copper-molybdenum plate 11 as a metal plate made of a metal material in which a porous sintered body of molybdenum is impregnated with 40% of molten copper. It is a formed configuration. The copper plating film 12 is provided on a portion corresponding to the package body bonding portion 81, and is not provided on the upper surface of the mounting portion 90. Then, the copper plating film 13 is
1, and is not provided on the lower surface of the mounting portion 90. In the present embodiment, the mounting portion 9
A gap d is formed between the fins 0 and the radiating fins 60, and the gap d has a configuration equal to the thickness of the copper plating film 13.

For the package body joining portion 81, a brazing material 15 such as silver brazing is used so that a package body 20 made of alumina as an insulating frame member formed in a frame shape surrounds the entire periphery of the semiconductor element mounting portion 31. Are joined. A space for mounting the semiconductor element 30 is formed by the metal plate 10 for heat dissipation and the package body 20. This space is hermetically sealed by joining a lid or the like (not shown) to the upper surface 21 of the package body 20 with a sealing material such as solder, low-melting glass, resin, or brazing material.

The package body 20 has a bonding pattern 23 made of tungsten, molybdenum, or the like, which is bonded to the metal plate 10 for heat dissipation via the brazing material 15 on the lower surface 22. From the inner periphery to the outer periphery, tungsten, molybdenum is used. And the like. Joining pattern 2
3 and the surface of the wiring pattern 24 are plated with nickel, gold, or the like. One end of the wiring pattern 24 is electrically connected to the electrode portion of the semiconductor element 30 via the bonding wire 40, and the other end of the conductor wiring layer 24 is connected to an external electric circuit such as a printed circuit board.
0 is electrically connected.

Next, a method for manufacturing the metal plate 10 for heat radiation will be described. (1) A copper-molybdenum plate is punched into a predetermined shape using a punching die, and a copper-molybdenum plate 11 having mounting portions 90 at both ends is manufactured as shown in FIG. The copper-molybdenum plate 11 has grooves 91 and 92 inside the mounting portion 90.

(2) As shown in FIG. 4, a copper plating film 12 and a copper plating film 12 are formed on both upper and lower surfaces of a copper-molybdenum plate 11 by an electrolytic plating method using a plating solution containing copper sulfate, copper nitrate or the like as a main component. The heat dissipation metal plate 10 is obtained by forming 13. At this time, a copper plating film 12 is provided on a portion corresponding to the package body joining portion, and a copper plating film 13 is provided on a portion corresponding to the heat radiation fin contact portion.

Next, a method of manufacturing the package body 20 will be described. (3) Magnesia, silica, calcined talc,
Powder to which a small amount of a sintering aid such as calcium carbonate and a coloring agent such as titanium oxide, chromium oxide, and molybdenum oxide are added,
A plasticizer such as dioxyl phthalate, a binder such as an acrylic resin or a butyral resin, and a solvent such as toluene, xylene and alcohol are added, and the mixture is sufficiently kneaded to obtain a viscosity of 200.
A slurry of 0 to 40000 cps is produced, and a plurality of 0.3 mm-thick alumina green sheets, for example, are formed by a doctor blade method.

(4) Each green sheet is processed into a desired shape using a punching die, a punching machine, or the like, and a plurality of via holes are punched to form a conductor using tungsten powder, molybdenum powder, or the like in each via hole. The vias are filled to form vias. An inner layer pattern is formed on the green sheet corresponding to the inner layer of the package body using the same conductive paste as the via. A conductor pattern is screen-printed on the green sheet corresponding to the front and back layers of the package body using the same conductor paste as the via.

(5) A green sheet corresponding to an inner layer having a via and an inner layer pattern formed thereon and a green sheet corresponding to a surface layer on which a conductor pattern is screen-printed,
This green sheet laminate is heated to, for example,
It is integrated by thermocompression bonding under the condition of 0 to 250 kg / cm ² .

(6) The integrated green sheet laminate is fired at 1500 to 1600 ° C. in a nitrogen-hydrogen mixed gas atmosphere. As a result, the resin component in the conductive paste is decomposed and eliminated, a wiring pattern is formed on the surface of the package body made of alumina, and a bonding pattern is formed on the back surface.

(7) The electrode portion and the bonding pattern of the formed wiring pattern are plated with nickel, gold, or the like to obtain the package body 20 shown in FIG.

(8) Next, the heat-dissipating metal plate 90 before the formation of the polished surface, prepared in the above steps (1) and (2), and the above (3)
The package body 20 manufactured in the steps (7) to (7) is joined using a brazing material such as silver brazing. At this time, thermal stress is generated due to the difference in the coefficient of thermal expansion between the metal plate 10 for heat radiation and the package body 20, and the end of the metal plate 10 for heat radiation is warped vertically downward, for example, as shown in FIG. That is, so-called convex warpage may occur. In FIG. 6, when the heat dissipation metal plate 10 and the package body 20 are joined, the heat dissipation metal plate 1
The warpage is exaggerated for easy understanding of the warpage occurring at zero. Although not shown, when the metal plate for heat radiation and the package body are joined, a so-called concave warp may occur in which the end of the metal plate for heat radiation warps vertically upward.

(9) The lead frame is electrically connected to the electrode portion of the wiring pattern, the semiconductor device is mounted on the semiconductor device mounting portion of the semiconductor package, and the electrode portion of the semiconductor device and the electrode portion of the wiring pattern are connected by wires. They are electrically connected by bonding. Thereafter, the semiconductor element mounting portion is hermetically sealed with a lid or the like, and then, the heat dissipating fins 60 are attached to the heat dissipating metal plate 10 as shown in FIG. And screw 70
The radiating fins 60 are fixed to the radiating metal plate 10 by using, and the radiating fin contact portions 61 are brought into close contact with the radiating fins 60. At this time, since the groove portions 91 and 92 are formed inside the mounting portion 90, when the heat dissipating metal plate 10 is excessively deformed at the time of attaching the heat dissipating fins 60, the heat dissipating metal plate 10 and the package body 20 are Cracks can be prevented from occurring at the interface of.

Next, in FIG. 6, length × width × thickness = 3
Heat-dissipating metal plate 1 with dimensions of 5 mm x 17 mm x 2.0 mm
0, and length × width × thickness = 27 mm × 15 mm × 1.
When the warpage in the longitudinal direction was measured using the package body 20 having a size of 0 mm, the warpage value was 4 to 50 μm. In FIG. 1, the thickness of the copper plating film 13 and the value of the gap d are 0.1 to 1 mm. Therefore, the heat dissipating fin contact portion 61 can adhere to the heat dissipating fin 60 with a high degree of adhesion. At this time, the value of the thermal conductivity of the metal plate 10 for heat radiation was 260 W / m · K or more.

In the present embodiment described above, since the gap d is formed between the mounting portion 90 and the radiating fins 60, the radiating fins 60 are mounted on the The degree of adhesion between the fin contact portion 61 and the heat radiation fin 60 is improved. Therefore, even when the semiconductor element 30 is placed and fixed on the semiconductor element mounting portion 31, the thermal resistance between the semiconductor element 30 and the heat radiation fins 60 can be easily reduced. Therefore, the heat generated during the operation of the semiconductor element 30 is satisfactorily radiated to the outside, and the semiconductor element 30
Can be operated normally and stably for a long time.

Further, in this embodiment, since the copper plating films 12 and 13 are formed on the upper and lower surfaces of the copper-molybdenum plate 11, the heat dissipating metal plate having an appropriate coefficient of thermal expansion and a high thermal conductivity is provided. 10 can be obtained. Therefore, when the heat-dissipating metal plate 10 and the package body 20 are joined, the warpage generated in the heat-dissipating metal plate 10 can be made relatively small, and the heat-dissipating metal plate 10 and the package body 20 are firmly joined. be able to.

Further, in the present embodiment, the thickness of the copper plating film 13 is equal to the gap d between the mounting portion 90 and the radiating fin 60, so that the heat radiating metal plate 10 can be easily manufactured. Thus, the gap d between the mounting portion 90 and the radiating fins 60 can be easily formed. Therefore,
The degree of adhesion between the heat dissipating fin contact portion 61 and the heat dissipating fin 60 can be easily improved, and the thermal resistance between the semiconductor element 30 and the heat dissipating fin 60 can be easily reduced.

In this embodiment, the copper plating films 12 and 13 are formed on the upper and lower surfaces of the copper-molybdenum plate 11, but in the present invention, copper plating may be formed on only one surface of the copper-molybdenum plate. Alternatively, a copper plating film may be formed on one or both sides of a metal plate made of molybdenum or copper-tungsten. Further, a metal sprayed film of copper or a printed and fired film of copper may be formed on one or both surfaces of a metal plate made of molybdenum, copper-molybdenum or copper-tungsten, or a metal made of molybdenum, copper-molybdenum or copper-tungsten. A copper plate may be joined to one or both surfaces of the plate by brazing.

In this embodiment, the present invention is applied to a surface mount type semiconductor package.
The present invention may be applied to an insertion type package such as a rid array) or other types of packages.

The present invention is applicable not only to electronic parts packages made of alumina but also to electronic parts packages made of any ceramics such as aluminum nitride, mullite, and low-temperature fired glass ceramics.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor package according to an embodiment of the present invention, taken along line II of FIG. 2;

FIG. 2 is a plan view showing a semiconductor package according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a metal plate according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a heat-dissipating metal plate according to an embodiment of the present invention.

FIG. 5 is a sectional view showing a package body according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a state in which a heat-dissipating metal plate and a package body according to one embodiment of the present invention are joined.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 Heat-dissipating metal plate 11 Copper-molybdenum plate (metal plate) 12, 13 Copper plating film 15 Brazing material 20 Package body (insulating frame member) 30 Semiconductor device (electronic component) 31 Semiconductor device mounting portion (electronic component mounting portion) Reference Signs List 60 radiating fin 61 radiating fin contact portion 90 mounting portion 91, 92 groove 100 semiconductor package (electronic component package)

Claims (3)

[Claims] 1. A heat-dissipating metal plate having an electronic component mounting portion for mounting an electronic component on an upper surface, and a space which is joined to the upper surface of the heat-dissipating metal plate and accommodates the electronic component on an inner side. An insulating frame member, a heat dissipating fin mounted on the lower surface of the heat dissipating metal plate, a contact portion provided on the lower surface of the heat dissipating metal plate and in close contact with the heat dissipating fin, and the adhesion of the heat dissipating metal plate And a mounting portion for mounting the heat-radiating fin to the heat-radiating metal plate. Package for parts. 2. The heat-dissipating metal plate is made of molybdenum, copper-
Molybdenum, a metal plate made of any metal material selected from copper-tungsten, and one selected from a copper plating film formed on one or both surfaces of the metal plate, a copper sprayed film, and a printed printing film of copper 2. The electronic component package according to claim 1, further comprising a copper film, or a copper plate joined to one or both surfaces of the metal plate by brazing. 3. The copper film or copper plate is formed or joined to one or both surfaces of the metal plate except for the mounting portion, and the thickness of the copper film or copper plate is equal to the gap. 3. The electronic component package according to claim 2, wherein: