JP2000236034A - Package for electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer a package for an electronic component, which has higher component bonding strength by preventing solder from flowing into the elec tronic component mount. SOLUTION: A package 20 has a stepped portion 21 at an end, which is positioned close to a semiconductor device mount 31 of the radiating metal plate 10. An end face 22 and the stepped portion 21 of the package 20, which are positioned close to the radiating metal plate 10, are provided with a joint pattern 23 for joining to the radiating plate 10 through a solder 15. The solder 15 creeps along the joint pattern 23 provided to the stepped portion 21, forming a solder accumulation 16 between the bonding pattern 23 and radiating metal plate 10. This prevents the solder 15 from flowing into the semiconductor device mount 31, thereby preventing the occurrence of bonding failure of a semiconductor device. Thus, the semiconductor device can be firmly secured to the radiating metal 10, ensuring correct and stable operation of the semiconductor device for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component package having an electronic component mounting portion for mounting an electronic component.

[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.

[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.

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 solder, the brazing material spreads over the upper surface of the heat-dissipating metal plate and spreads over the electronic component mounting portion. There is a problem of flowing. Hereinafter, the reason why the above problem occurs will be described.

The required amount of brazing material is determined by the clearance between the metal plate for heat dissipation and the ceramic package body. If the clearance becomes smaller than a certain level due to manufacturing variations, extra brazing other than that involved in joining is required. The material flows out to a portion other than the joint on the metal plate for heat radiation. The excess brazing material that flows out flows into the electronic component mounting portion.

When the brazing material flows into the electronic component mounting portion, unevenness is formed in the electronic component mounting portion, so that a gap is formed below the electronic component when the electronic component is mounted, and a defective connection of the electronic component occurs. Might be. Therefore, there is a problem that the electronic component cannot be firmly fixed to the metal plate for heat radiation.

The present invention has been made to solve such a problem, and provides an electronic component package that prevents a brazing material from flowing into an electronic component mounting portion and improves the joining strength of the electronic component. The purpose is to do.

[0010]

According to the electronic component package according to the first aspect of the present invention, the joining portion joined to the heat radiating metal plate by the brazing material is the end of the insulating frame member on the heat radiating metal plate side. And a brazing material storage portion for storing the brazing material is formed between the joint portion and the metal plate for heat radiation. Therefore, at the time of brazing, excess brazing material is stored in the brazing material storage portion, and it is possible to prevent the brazing material from flowing into the electronic component mounting portion. Thereby, it is possible to prevent the occurrence of a bonding failure of the electronic component, and to firmly fix the electronic component to the heat dissipation metal plate. Therefore, the electronic component can be normally and stably operated for a long time.

According to the electronic component package of the second aspect of the present invention, the joining portion is provided on the end surface of the insulating frame member on the side of the heat-dissipating metal plate and on the outer peripheral surface near the end surface. For this reason, at the time of brazing, the brazing material creeps up along the joining portion provided on the outer peripheral surface near the end surface of the insulating frame member, and a brazing material accumulation portion is formed between the joining portion and the metal plate for heat radiation. Therefore, by preventing the brazing material from flowing into the electronic component mounting portion, it is possible to prevent defective bonding of the electronic component and improve the bonding strength of the electronic component.

According to the electronic component package of the third aspect of the present invention, since the insulating frame member has a step at the end on the side of the heat-dissipating metal plate, a joint is provided at the step. At the time of brazing, the brazing material creeps up along the joining portion, and a brazing material accumulation portion is formed between the joining portion and the metal plate for heat radiation. Therefore, it is possible to prevent the brazing material from flowing into the electronic component mounting portion, to prevent defective bonding of the electronic component, and to improve the bonding strength of the electronic component.

According to the electronic component package of the fourth aspect of the present invention, since the bonding portion has an uneven portion, a brazing material accumulation portion is formed between the uneven portion and the metal plate for heat radiation. . Therefore, it is possible to prevent the brazing material from flowing into the electronic component mounting portion, to prevent defective bonding of the electronic component, and to improve the bonding strength of the electronic component.

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. For this reason, the width and thickness of the brazing material flowing on the heat-dissipating metal plate during brazing can be reduced as compared with forming a nickel film on one or both surfaces of the metal plate. Therefore, it is possible to prevent the brazing material from flowing into the electronic component mounting portion, to prevent defective bonding of the electronic component, and to improve the bonding strength of the electronic component.

Further, 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, an appropriate coefficient of thermal expansion and a high thermal conductivity can be obtained. It is possible to obtain a heat-dissipating metal plate.

Forming a copper film selected from a copper plating film, a copper sprayed film, and a printed and baked copper 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 joining a copper plate by brazing to both surfaces of the metal plate 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 by the value of the upper layer of the heat-dissipating metal plate immediately below the semiconductor element. 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.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. First Embodiment FIG. 1 shows a first embodiment in which the present invention is applied to a surface mount type semiconductor package made of ceramics.
This will be described with reference to FIG.

As shown in FIGS. 1 and 2, a semiconductor package 100 made of ceramics includes a metal plate 10 for heat radiation,
It is composed of a package body 20 made of alumina, a lead frame 50 and the like.

The heat dissipating metal plate 10 has a semiconductor element mounting portion 31 on which the semiconductor element 30 is mounted and fixed on the upper surface thereof.
It is mounted and fixed using an adhesive such as glass, resin, or brazing material.

The heat-dissipating metal plate 10 has copper plating films 12 and 13 formed on both upper and lower surfaces of a copper-tungsten plate 11 as a metal plate made of a metal material in which a porous sintered body of tungsten is impregnated with molten copper. Configuration.

A package body 20 made of alumina as a frame-shaped insulating frame member is joined to the upper surface of the heat-dissipating metal plate 10 using a brazing material 15 so as to surround the entire periphery of the semiconductor element mounting portion 31. Have been. The brazing material 15 is preferably a silver brazing material, containing 72 to 85% by weight of silver and containing 15% of copper.
Silver-copper eutectic alloys containing up to 28% by weight are more preferred. The semiconductor element 3 is composed of the heat dissipating metal plate 10 and the package body 20.
A space for mounting 0 is formed. This space is hermetically sealed by joining a lid or the like (not shown) to the upper surface of the package body 20 with a sealing material such as solder, low-melting glass, resin, or brazing material.

The package body 20 is made of a metal plate 10 for heat radiation.
Side of the semiconductor element mounting portion 31
One. Metal plate 1 for heat radiation of package body 20
A bonding pattern 23 as a bonding portion made of tungsten, molybdenum, or the like that is bonded to the metal plate 10 for heat dissipation via the brazing material 15 is provided on the end surface 22 on the 0 side and the step portion 21. The surface of the bonding pattern 23 is plated with nickel, gold, or the like. The brazing material 15 is creeping up along the joining pattern 23 provided on the step portion 21, and the brazing material 15 is located between the joining pattern 23 and the metal plate 10 for heat radiation.
Is accumulating. That is, the brazing material pool 16 is formed between the joint pattern 23 and the metal plate 10 for heat radiation.

A plurality of wiring patterns 24 such as tungsten and molybdenum are formed from the inner peripheral portion to the outer peripheral portion of the package body 20. The surface of the wiring pattern 24 is plated with nickel, gold, or the like. One end of the wiring pattern 24 is electrically connected to an electrode portion of the semiconductor element 30 via a bonding wire 40, and the other end of the conductive wiring layer 24 is connected to a lead frame 50 connected to an external electric circuit such as a printed circuit board. It is electrically connected.

Next, a method for manufacturing the heat-dissipating metal plate 10 will be described. (1) The copper-tungsten plate 11 is sintered at 800 ° C. in a nitrogen-hydrogen mixed gas atmosphere. Then, for example, a copper-tungsten plate 11 is formed by an electrolytic plating method using a plating solution containing nickel sulfate, nickel chloride or the like as a main component.
A nickel plating thin film having a plating thickness of 1.0 μm is formed on the upper and lower surfaces of
Further sintering at 0 ° C. Further, for example, sulfuric acid,
A copper plating film 12 and 13 having a plating thickness of 15 μm is formed on both upper and lower surfaces of a copper-tungsten plate having a nickel plating thin film formed thereon by an electrolytic plating method using a plating solution containing copper nitrate or the like as a main component. The metal plate 10 for use is obtained.

Next, a method of manufacturing the package body 20 will be described. (2) Magnesia, silica, calcined talc, alumina powder
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.

(3) Each green sheet is processed into a desired shape by 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.

(4) 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 .

(5) 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. (6) The package body 20 is obtained by plating the electrode portions and the bonding patterns of the formed wiring pattern with nickel, gold, or the like.

(7) Next, the heat-dissipating metal plate 10 produced in the above step (1) and the package body 20 produced in the above steps (2) to (6) are soldered together with a solder such as silver solder. Join using materials. At this time, the brazing material 15 creeps up along the bonding pattern 23 provided on the step portion 21 of the package body 20, and the brazing material accumulation portion 16 is formed between the bonding pattern 23 and the metal plate 10 for heat radiation. For this reason, the excess brazing material 15 is stored in the brazing material storage portion 16, and it is possible to prevent the brazing material 15 from flowing into the semiconductor element mounting portion 31.

(8) The lead frame 50 is electrically connected to the electrode portion of the wiring pattern 24, and the semiconductor package 100
The semiconductor element 30 is mounted on the semiconductor element mounting section 31, and the electrode section of the semiconductor element 30 and the electrode section of the wiring pattern 24 are electrically connected by wire bonding. Thereafter, the semiconductor element mounting portion 31 is hermetically sealed with a lid or the like.

Next, FIG. 6 shows a comparative example in which nickel plating films are formed on the upper and lower surfaces of the copper-tungsten plate 11 of the first embodiment shown in FIG. It will be described using FIG. The substantially same parts as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 6, in the comparative example, nickel plating films 112 and 113 are formed on the upper and lower surfaces of the copper-tungsten plate 11, respectively.
A bonding pattern 223 as a bonding portion of tungsten, molybdenum, or the like that is bonded to the metal plate for heat radiation via a brazing material 215 is provided on the end surface 222 on the side of the metal plate for heat radiation. The surface of the bonding pattern 223 is plated with nickel, gold, or the like.

In the comparative example, at the time of brazing, extra brazing material 215 not involved in joining flows out to a portion other than the joining portion on the heat-dissipating metal plate, and the extra brazing material 215 flowing out is mounted on the semiconductor element. It flows into the part 31 and the unevenness is formed on the electronic component mounting part 31. Therefore, there is a possibility that a bonding failure of the semiconductor element may occur, and the semiconductor element cannot be firmly fixed to the metal plate for heat radiation.

On the other hand, in the first embodiment, the brazing filler metal portion 16 is provided between the bonding pattern 23 and the metal plate 10 for heat radiation.
Is formed, it is possible to prevent the brazing material 15 from flowing into the semiconductor element mounting portion 31. As a result, it is possible to prevent the occurrence of a bonding failure of the semiconductor element 30,
The semiconductor element 30 can be firmly fixed to the metal plate 10 for heat radiation. Therefore, the semiconductor element 30 can be normally and stably operated for a long time.

Further, in the first embodiment, the copper plating films 12 and 13
Is formed, the width and thickness of the brazing material 15 flowing on the heat-dissipating metal plate 10 can be reduced during brazing as compared with the comparative example.
5 can be further prevented from flowing. Also,
Copper plating film 12 on both upper and lower surfaces of copper-tungsten plate 11
By forming and 13, the heat-dissipating metal plate 10 having an appropriate coefficient of thermal expansion and a high thermal conductivity 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.

(Second Embodiment) The package body 20 of the first embodiment shown in FIG. 1 does not have a step, and the end face 22 of the package body 20 on the side of the metal plate 10 for heat radiation and the end face 2
A second embodiment in which a bonding pattern is provided on the outer peripheral surface near 2 will be described with reference to FIG. The substantially same parts as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 3, in the second embodiment, the end face 7 of the package body 70 on the side of the metal plate 10 for heat radiation is used.
2, and a bonding pattern 73 as a bonding portion of tungsten, molybdenum, or the like, which is bonded to the metal plate 10 for heat dissipation via the brazing material 65 on the outer peripheral surface 71 near the end surface 72. The surface of the bonding pattern 73 is plated with nickel, gold, or the like. The brazing material 65 is creeping up along the joining pattern 73 provided on the outer peripheral surface 71,
The brazing material 6 is provided between the joining pattern 73 and the heat-dissipating metal plate 10.
5 has accumulated. That is, the brazing material pool 66 is formed between the joining pattern 73 and the metal plate 10 for heat radiation. Therefore, at the time of brazing, it is possible to prevent the brazing material 65 from flowing into the semiconductor element mounting portion 31. Thereby, it is possible to prevent the occurrence of a bonding failure of the semiconductor element, and to firmly fix the semiconductor element to the metal plate 10 for heat radiation. Therefore, the semiconductor element can be normally and stably operated for a long time.

(Third Embodiment) Steps are formed at the semiconductor device mounting portion 31 side and the end opposite to the semiconductor device mounting portion side of the package body 20 of the first embodiment shown in FIG. A third embodiment in which a joining pattern is provided on the end surface 22 and the step portion on the side of the metal plate 10 will be described with reference to FIG. The substantially same parts as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 4, in the third embodiment, the package body 120 is a stepped portion at the end of the heat dissipating metal plate 10 and on the side of the semiconductor element mounting section 31 and the side opposite to the semiconductor element mounting section. It has a part 121. A bonding pattern 123 as a bonding portion of tungsten, molybdenum, or the like, which is bonded to the metal plate for heat dissipation 10 via a brazing material 115, is provided on an end surface 122 of the package body 120 on the side of the metal plate for heat dissipation 10 and the step portion 121. . Joining pattern 1
The surface of 23 is plated with nickel, gold, or the like. The brazing material 115 is creeping up along the joining pattern 123 provided on the step portion 121, and the joining pattern 1
The brazing material 115 is stored between the metal plate 23 and the metal plate 10 for heat radiation. That is, the brazing material pool 116 is formed between the joining pattern 123 and the metal plate 10 for heat radiation.
For this reason, at the time of brazing, the brazing material 1
15 can be prevented from flowing. Thereby, it is possible to prevent the occurrence of a bonding failure of the semiconductor element, and to firmly fix the semiconductor element to the metal plate 10 for heat radiation. Therefore, the semiconductor element can be normally and stably operated for a long time.

(Fourth Embodiment) A bonding pattern having an uneven portion on the end face 22 of the package body 20 on the side of the metal plate 10 for heat radiation without forming a step portion in the package body 20 of the first embodiment shown in FIG. A fourth embodiment provided will be described with reference to FIG. The substantially same parts as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 5, in the fourth embodiment, tungsten, molybdenum, or the like, which is joined to the heat-dissipating metal plate 10 via the brazing material 165 on the end surface 172 of the package body 170 on the heat-dissipating metal plate 10 side. A bonding pattern 173 is provided as a bonding portion. Joining pattern 17
The surface of No. 3 is plated with nickel, gold or the like.
The bonding pattern 173 is provided on the heat dissipation metal plate 10 side with the recess 17.
4 and a convex portion 175. A brazing material 165 is stored between the concave portion 174 and the metal plate 10 for heat radiation. That is, the brazing material pool 166 is formed between the joint pattern 173 and the metal plate 10 for heat radiation. Therefore, it is possible to prevent the brazing material 165 from flowing into the semiconductor element mounting portion 31 during brazing. As a result, it is possible to prevent the occurrence of bonding failure of the semiconductor element, and
The semiconductor element can be firmly fixed at the same time. Therefore, the semiconductor element can be normally and stably operated for a long time.

In the embodiments described above, copper-
Although the copper plating films 12 and 13 are formed on both upper and lower surfaces of the tungsten plate 11, in the present invention, copper plating may be formed on only one surface of the copper-tungsten plate, or a metal made of molybdenum or copper-molybdenum may be used. A copper plating film may be formed on one or both sides of the plate. Further, a thermal sprayed film of copper or a printed and baked 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 the above embodiments, 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 (Pin Grid Array) or another type of package.

The present invention is applicable not only to electronic component packages made of alumina but also to electronic device 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 a first embodiment of the present invention, taken along line II of FIG. 2;

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

FIG. 3 is a sectional view showing a semiconductor package according to a second embodiment of the present invention;

FIG. 4 is a sectional view showing a semiconductor package according to a third embodiment of the present invention.

FIG. 5 is a sectional view illustrating a semiconductor package according to a fourth embodiment of the present invention;

FIG. 6 is a sectional view showing a semiconductor package according to a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Heat-dissipation metal plate 11 Copper-tungsten plate (metal plate) 12, 13 Copper plating film 15, 65, 115, 165 Brazing material 16, 66, 116, 166 Brazing material storage part 20, 70, 120, 170 Package body (Insulating frame member) 21, 121 Step portion 22, 72, 122, 172 End surface 23, 73, 123, 173 Joining pattern (joining portion) 30 Semiconductor element (electronic component) 31 Semiconductor element mounting portion (electronic component mounting portion) 71 Outer peripheral surface 100 Semiconductor package (package for electronic component) 174 Concave portion (irregular portion) 175 Convex portion (irregular portion)

Claims (5)

[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 joint provided at an end of the insulating frame member on the side of the heat-dissipating metal plate, and joined to the heat-dissipating metal plate by a brazing material; and An electronic component package, comprising: a brazing material storage portion formed between the brazing materials, for storing the brazing material. 2. The electronic component package according to claim 1, wherein the joining portion is provided on an end surface of the insulating frame member on the side of the heat-dissipating metal plate and an outer peripheral surface near the end surface. . 3. The heat-dissipating frame member has a step at the end on the heat-dissipating metal plate side.
Or the package for electronic components of 2. 4. The electronic component package according to claim 1, wherein the bonding portion has an uneven portion. 5. 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 5. A copper film, or a copper plate joined to one or both surfaces of the metal plate by brazing.
Electronic component package according to the item.