JPH07211822A - Package for accommodating semiconductor element - Google Patents

Abstract

PURPOSE:To rigidly solder and bond insulator composed of aluminum oxide based sindered body to a metal radiator having high thermal conductivity without generating large distortion, effectively dissipate the heat generated at the time of operating a semiconductor element toward the outside, and normally and stably operate the semiconductor element for a long term. CONSTITUTION:The package is constituted by soldering a radiator 1 to insulator 2 which is composed of aluminum oxide based sintered body and has a space for accommodating a semiconductor element in the inside. The metal radiator 1 is formed by soldering copper plates 5, 6 on the surface and the rear of a molybdenum plate 4. When the thickness of the molybdenum plate 4 is T1, the thickness of the copper plates 5, 6 is T2, T2/T1 is 1.25-4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element housing package for housing a semiconductor element.

[0002]

2. Description of the Related Art Conventionally, a semiconductor element accommodating package for accommodating a semiconductor element comprises a metal radiator having a mounting portion on which the semiconductor element is mounted and fixed, and an aluminum oxide sintered body. A hole for forming a space for accommodating a semiconductor element, and a frame-shaped insulator having a plurality of metallized wiring layers led out from the periphery of the hole to the outer periphery. A frame-shaped insulator is formed on the upper surface of the body by brazing so that the frame-shaped insulator surrounds the semiconductor element mounting portion of the metal radiator.

In such a conventional package for accommodating semiconductor elements, the semiconductor element is mounted and fixed on the semiconductor element mounting portion of the metal radiator via an adhesive such as a brazing material, and each electrode of the semiconductor element is insulated. Electrically connected to the metallized wiring layer of through a bonding wire or other electrical connection means,
After that, a lid made of metal, ceramics, glass, etc. is joined to the upper surface of the insulator through a sealing material such as glass, resin, solder, etc., and the semiconductor element is hermetically sealed inside to form the final product. Semiconductor device.

In addition, the metal radiator is firmly brazed with an insulator made of an aluminum oxide sintered body, and the heat generated during the operation of the semiconductor element is well dissipated into the atmosphere. The coefficient of thermal expansion obtained by integrally bonding the copper plates to the upper and lower surfaces of the molybdenum plate as described in the publication by rolling is close to the coefficient of thermal expansion of the insulator,
Moreover, a composite material having a thermal conductivity of about 150 W / mk is used.

[0005]

However, in recent years,
The density and integration of semiconductor devices have rapidly increased, and the amount of heat generated per unit area and unit volume during operation of the semiconductor devices has increased sharply. Therefore, in the conventional package for semiconductor element storage, the thermal conductivity of the metal radiator is about 150 W / m.
Since it is k, it becomes difficult to completely dissipate the heat generated during the operation of the semiconductor element to the outside through the metal radiator.
As a result, the semiconductor element has a high temperature due to the heat generated by the element itself, causing a thermal breakdown in the semiconductor element or causing a thermal change in the characteristics of the semiconductor element, which causes a malfunction in the semiconductor element. Was there.

Therefore, in order to solve the above-mentioned drawbacks, the thickness of the copper plate having a large thermal conductivity of the composite material (the material in which the copper plates are integrally joined by the rolling process to the upper and lower surfaces of the molybdenum plate) for forming the metal radiator is set. It is conceivable that the molybdenum plate having a low thermal conductivity is made thicker to improve the thermal conductivity of the metal radiator.

However, when the thickness of the copper plate is made thicker than that of the molybdenum plate, molybdenum has the property of being hard and less malleable, whereas copper is soft and has the property of being malleable, so that molybdenum is molybdenum. When copper plates are integrally joined to the upper and lower sides of the plate by rolling, it is difficult to perform uniform rolling because the properties of the two are greatly different, and the thickness of the molybdenum plate and the copper plate usually varies by about ± 5%. As a result, the coefficient of thermal expansion of the metal radiator will be partially different, and the processing stress during rolling will remain unevenly on the metal radiator, and the insulator will be connected to the metal radiator via the brazing material. When joining by bonding, it is said that the metal radiator is greatly deformed and the insulator cannot be firmly joined to the metal radiator, and the semiconductor element cannot be firmly fixed to the metal radiator. The disadvantage is induced.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object of the present invention is to provide a metal radiator having a high thermal conductivity with an insulator made of an aluminum oxide sintered body, which is greatly deformed. Firmly brazing without generating
It is an object of the present invention to provide a package for accommodating a semiconductor element, which can satisfactorily dissipate heat generated during the operation of the semiconductor element to the outside and operate the semiconductor element normally and stably for a long period of time.

[0009]

SUMMARY OF THE INVENTION The present invention is for accommodating a semiconductor device in which a metal radiator is brazed to an insulator made of an aluminum oxide sintered body having a cavity for accommodating a semiconductor device therein. In the package, the metal radiator is formed by brazing copper plates on the upper and lower surfaces of a molybdenum plate, and the thickness of the molybdenum plate is T1 and the thickness of the copper plate is T2.
Then, T2 / T1 is 1.25 to 4.

[0010]

According to the package for accommodating semiconductor elements of the present invention, the metal radiator is formed of the composite material in which the copper plates are brazed on the upper and lower surfaces of the molybdenum plate, and the thickness of the molybdenum plate is T1 and the thickness of the copper plate is T2. At this time, since T2 / T1 is limited to the range of 1.25 to 4, the thermal conductivity of the metal radiator is 250 W / mk or more, and as a result, the heat generated during the operation of the semiconductor element is externally transmitted through the metal radiator. The semiconductor element can be normally and stably operated at a low temperature for a long period of time.

Further, according to the package for housing a semiconductor element of the present invention, since the metal radiator is formed by brazing the copper plates on the upper and lower surfaces of the molybdenum plate, the thickness variation of the molybdenum plate and the copper plate is prevented. As a result, when the insulator is joined to the metal radiator via the brazing material, no large deformation occurs in the metal radiator and the metal radiator can be made flat. This makes it possible to bring the metal heat radiator and the insulator into close contact with each other and firmly braze them together, and also to firmly fix the semiconductor element to the metal heat radiator.

[0012]

The present invention will now be described in detail with reference to the accompanying drawings.

1 and 2 show an embodiment of a package for housing a semiconductor device according to the present invention, in which 1 is a metal radiator and 2 is an insulator.

The metal radiator 1 has a mounting portion A on which the semiconductor element 3 is mounted and fixed, and the semiconductor element 3 is bonded to the mounting portion A by glass, resin, brazing material or the like. It is placed and fixed through the agent.

The metal heat radiator 1 has a structure in which copper plates 5 and 6 are bonded to the upper and lower surfaces of a molybdenum plate 4 with a brazing material 7 such as silver brazing material. When the semiconductor element 3 is mounted and fixed on the metal radiator 1, the metal radiator 1 absorbs the heat generated by the semiconductor element 3 and has a high conductivity of 250 W / mk or more and is extremely easy to conduct heat. The absorbed heat can be satisfactorily dissipated to the atmosphere, and as a result, the semiconductor element 3 can be kept at a low temperature at all times, and the semiconductor element 3 can be normally and stably operated for a long period of time.

The metal radiator 1 is prepared in advance by preparing a flat molybdenum plate 4 and copper plates 5 and 6 by a conventionally known metal working method, and then the copper plates 5 are formed on the upper and lower surfaces of the flat molybdenum plate 4. 6 is placed by sandwiching a brazing material such as silver brazing material between them, and then the brazing material is heated and melted, and the molybdenum plate 4 and the copper plates 5 and 6 are brazed and joined together. , 6 are joined by brazing and no external force is applied to the molybdenum plate 4 and the copper plates 5, 6 so that the molybdenum plate 4 and the copper plates 5, 6 have a uniform thickness. As a result, the coefficient of thermal expansion of the metal radiator 1 does not differ partially, and when the insulator 2 described later is brazed to the metal radiator 1 via a brazing material such as silver braze, Causing a large deformation No, it is possible to firmly fix the semiconductor element 3 to the metal heat radiating member 1 with a strengthened brazed joint between the metal radiator body 1 and the insulator 2.

Further, the metal radiator 1 has a coefficient of thermal expansion
Since it is 7.0 to 8.5 × 10 ^-6 / ℃, which is close to the coefficient of thermal expansion of the insulator 2, even if the insulator 2 is joined to the metal radiator 1 through a brazing material such as silver braze, it will be between them. Is unlikely to generate thermal stress due to the difference in thermal expansion coefficient,
The bonding strength between the metal radiator 1 and the insulator 2 can be made extremely strong.

The metal radiator 1 formed by brazing copper plates 5 and 6 on the upper and lower surfaces of the molybdenum plate 4 has a coefficient of thermal expansion of the molybdenum plate 4 of 5.1 × 10 ⁻⁶ / ° C. and heat of the copper plates 5 and 6. The expansion coefficient is 17 × 10 ^-6 / ℃, the molybdenum plate 4 is a copper plate 5,
The thermal expansion coefficient of the insulator 2 (6.0 × 10 ^-6 / ℃ ~ 7.5 × 10 ^-6 / ℃)
It is assumed to be close to.

Further, the metal radiator 1 formed by brazing the copper plates 5 and 6 on the upper and lower surfaces of the molybdenum plate 4 is caused by the difference in thermal expansion coefficient between the molybdenum plate 4 and the copper plates 5 and 6. Thermal stress will be offset on the front and back sides,
As a result, the metal radiator 1 is always flat and the metal radiator 1 is
The semiconductor element 3 can be firmly joined to the semiconductor element mounting portion A of FIG.

Further, the metal radiator 1 made by brazing copper plates 5 and 6 on both upper and lower surfaces of the molybdenum plate 4 has a thickness T1 of the molybdenum plate 4 and a thickness T2 of the upper and lower copper plates 5 and 6. When / T1 is less than 1.25, the thermal conductivity of the metal radiator 1 becomes low, the heat generated by the semiconductor element 3 cannot be sufficiently removed, and the thermal expansion coefficient of the insulator 2 is large.
And the brazing joint strength between the metal radiator 1 and the insulator 2 is reduced, or the metal radiator 1 is warped, so that the semiconductor element 3 cannot be firmly fixed. , And when T2 / T1 exceeds 4, a metal radiator 1
The coefficient of thermal expansion of the semiconductor element 2 becomes larger than the coefficient of thermal expansion of the insulator 2, the brazing joint strength between the metal radiator 1 and the insulator 2 is reduced, or the metal radiator 1 is warped, and the semiconductor element Three
Will not be able to be firmly fixed. Therefore, in the metal radiator 1, the thickness of the molybdenum plate 4 is T1,
When the thickness of the upper and lower copper plates 5 and 6 is T2, T2 / T1 is limited to the range of 1.25 to 4.

Furthermore, in the metal radiator 1, the thickness of the brazing material 7 for joining the molybdenum plate 4 and the copper plates 5, 6 is 0.02 mm.
When the copper plates 5 and 6 are brazed to the upper and lower surfaces of the molybdenum plate 4 via the brazing filler metal 7, a large number of voids (holes) are formed inside the brazing filler metal 7 and the heat conduction of the metal radiator 1 is reduced. There is a risk of lowering the rate. Therefore, the brazing material 7
Is preferably 0.02 mm or more in thickness in order to prevent voids from being formed inside and lowering the thermal conductivity of the metal radiator 1.

The metal radiator 1 has a frame-shaped insulator 2 bonded to the upper surface thereof through a brazing material such as silver brazing so as to surround the semiconductor element mounting portion A of the metal radiator 1.
A space for accommodating the semiconductor element 3 is formed inside by the metal radiator 1 and the insulator 2.

The insulator 2 bonded to the upper surface of the metal radiator 1 is made of an aluminum oxide sintered material, and for example, aluminum oxide sintered material powder such as aluminum oxide, silicon oxide, calcium oxide and magnesium oxide. A suitable organic binder and solvent are added and mixed to form a slurry, and a plurality of ceramic green sheets (ceramic green sheets) are formed by using a sheet forming technique such as the well-known doctor blade method. Conventionally well-known punching technology is applied to a plurality of ceramic green sheets, and appropriate punching processing is performed on each of them, and these are stacked on top of each other to obtain a ceramic green sheet laminated body, and finally the ceramic green sheet laminated body is subjected to a reducing atmosphere. It is manufactured by firing at a temperature of about 1600 ° C. in the middle.

A metallized bonding layer 8 made of a high melting point metal powder such as tungsten, molybdenum, or manganese is deposited on the lower surface of the insulator 2, and the metallized bonding layer 8 is insulated from the metal radiator 1. A metal paste that acts as a base metal when joining the body 2 through a brazing filler metal, and a metal paste obtained by adding and mixing an appropriate binder and solvent to a refractory metal powder such as tungsten or molybdenum is used as the insulator 2. The green sheet is preliminarily printed and applied by a thick film method such as screen printing to be attached to the lower surface of the insulator 2 to a predetermined thickness.

The metallized bonding layer 8 is metallized on its outer surface by plating with a metal such as nickel or gold having excellent corrosion resistance and brazing wettability to a thickness of 0.1 to 10.0 μm. It is possible to effectively prevent the bonding layer 8 from being oxidized and corroded, and to strengthen the bonding between the metallized bonding layer 8 and the metal substrate 1. Therefore, it is preferable that the outer surface of the metallized bonding layer 8 be coated with a metal such as nickel and gold having excellent corrosion resistance and brazing wettability in a thickness of 0.1 to 10.0 μm.

Further, the insulator 2 is provided with a plurality of metallized wiring layers 9 made of high melting point metal powder such as tungsten, molybdenum, manganese, etc. from the inner peripheral portion to the outer peripheral portion thereof, and one end of the metallized wiring layer 9 has a semiconductor. The electrodes of the element 3 are connected via a bonding wire 10, and the other end is externally brazed with an external lead terminal 11 connected to an external electric circuit via a brazing material such as silver solder.

The metallized wiring layer 9 is a thick film formed by screen printing or the like in advance on a ceramic green sheet serving as the insulator 2 with a metal paste obtained by adding and mixing a suitable binder and a solvent to a refractory metal powder such as tungsten or molybdenum. By printing and applying a predetermined pattern by a method, the insulator 2 is adhered and formed from the inner peripheral portion to the outer peripheral portion.

The external lead terminal 11 brazed to one end of the metallized wiring layer 9 is made of a metal material such as iron-nickel alloy or iron-nickel-cobalt alloy, and the external lead terminal 11 is connected to an external electric circuit. By doing so, the electrodes of the semiconductor element 3 housed inside are electrically connected to the external electric circuit.

The external lead terminal 11 is made of iron-nickel alloy or the like by rolling, punching, etching or the like.
It is formed into a predetermined plate shape by adopting a conventionally known metal processing method, and one end thereof is brazed to the metallized wiring layer 9 of the insulator 2 via a brazing material such as silver brazing.

It should be noted that the external lead terminal 11 is provided with a metal such as nickel and gold having excellent corrosion resistance and solder wettability on the surface thereof by plating to a thickness of 0.1 to 10.0 μm. Oxidation and corrosion of the lead terminals 11 can be effectively prevented, and the external lead terminals 11 can be firmly connected to the external electric circuit via solder. Therefore, the external lead terminal 11 has nickel on its outer surface.
It is preferable to mount a metal such as gold having excellent corrosion resistance and solder wettability to a thickness of 0.1 to 10.0 μm.

Thus, according to the semiconductor element housing package of the present invention, the semiconductor element 3 is mounted on the semiconductor element mounting portion A of the metal radiator 1 surrounded by the insulator 2 via an adhesive such as a brazing material. Then, the electrodes of the semiconductor element 3 are connected to the metallized wiring layer 9 of the insulator 2 via the bonding wires 10, and then the lid 12 is placed on the upper surface of the insulator 2.
Are joined together via a sealing material such as solder, glass, or resin, and the semiconductor element 3 is hermetically sealed inside, so that a semiconductor device as a final product is obtained.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above-mentioned embodiments,
On the exposed surface of the metal heat sink 1, a metal such as nickel, gold, etc., which has excellent corrosion resistance and brazing wettability, is 0.1 to 10.0 μm.
When the metal radiator 1 is attached to the thickness of m by the plating method, the metal radiator 1 can be firmly brazed to the insulator 2 while effectively preventing the metal radiator 1 from being oxidized and corroded.

In the above-described embodiment, the semiconductor element housing package in which the frame-shaped insulator 2 is joined to the upper surface of the metal radiator 1 has been described as an example, but the container for housing the semiconductor element 3 is made of aluminum oxide. It is also applicable to a package for housing a semiconductor element, which is made of an insulating material made of a high quality sintered body and has a metal heat radiator bonded to the outer surface of the container.

[0034]

According to the package for accommodating semiconductor elements of the present invention, the metal radiator is formed of the composite material in which the copper plates are brazed on the upper and lower surfaces of the molybdenum plate, and the thickness of the molybdenum plate is T1 and the thickness of the copper plate is T2. Then, T2 / T
Since 1 is limited to the range of 1.25 to 4, the thermal conductivity of the metal radiator is 250 W / mk or more, and as a result, the heat generated during the operation of the semiconductor element is well dissipated to the outside through the metal radiator. As a result, the semiconductor element can always be operated at a low temperature and can operate normally and stably for a long period of time.

Further, according to the package for accommodating semiconductor elements of the present invention, since the metal radiator is formed by brazing and joining the copper plates to the upper and lower surfaces of the molybdenum plate, variation in the thickness of the molybdenum plate or the copper plate occurs. As a result, when the insulator is joined to the metal radiator via the brazing material, no large deformation occurs in the metal radiator and the metal radiator can be made flat. This makes it possible to bring the metal heat radiator and the insulator into close contact with each other and firmly braze them together, and also to firmly fix the semiconductor element to the metal heat radiator.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a package for housing a semiconductor device of the present invention.

FIG. 2 is a sectional view taken along line XX of the package shown in FIG.

[Explanation of symbols]

 1 ... Metal heat sink 2 ... Insulator 3 ... Semiconductor element 4 ... Molybdenum plate 5, 6 ... Copper plate 7 ... Brazing material

Claims (1)

[Claims] 1. A semiconductor element housing package comprising a metal heat radiator brazed to an insulator made of an aluminum oxide sintered body having a cavity for housing a semiconductor element therein. When the body is formed by brazing copper plates on both upper and lower surfaces of the molybdenum plate, and the thickness of the molybdenum plate is T1 and the thickness of the copper plate is T2, T2 / T1 is 1.
25 to 4 is a package for housing a semiconductor element.