JPH05226514A - Semiconductor element containing package - Google Patents

Abstract

PURPOSE:To actuate a semiconductor element normally and stably by a method wherein a metallic substrate is effectivelly prevented from warping so as to efficiently absorb the heat generated by the semiconductor chip. CONSTITUTION:Within the tile semiconductor element containing package, an iron alloy made frame member 2 having an insulating member 3 engaged therewith is attached to the surface outer periphery of a metallic substrate 1 so as to fixedly contain a semiconductor chip 4 in a space formed by the surface of the semiconductor chip 1 and the frame member 2 to be contained in the space. In such a constitution, the metallic substrate 1 is composed of a molybdenum plate 5 with copper plates 6, 7 junctioned with upper and lower surfaces while assuming the thickness of the molybdenum plate 5, the copper plate 6 positioned on the upper surface side whereto the semiconductor chip 4 is fixed and the other copper plate 7 positioned on the rear surface side respectively as T1, T2, T3, T2/T1 = to while T3/T2=-T2/12T1+1.3 to -T2/12T1+1.6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to an improvement of a semiconductor device housing package for housing a high power, high frequency power transistor and the like.

[0002]

2. Description of the Related Art Conventionally, a semiconductor element accommodating package for accommodating high-output, high-frequency power transistors and the like has a metal base body having a mounting portion on which a semiconductor element is mounted and fixed, and the mounting portion. A frame member that is attached to the outer peripheral portion of the upper surface of the metal base via a brazing material such as silver solder so as to surround the metal base, and the electrode of the semiconductor element that is fitted inside the through hole provided in the frame member and is externally And an insulating member having a metallized wiring layer for connecting to an electric circuit,
The semiconductor element is mounted and fixed on the semiconductor element mounting portion of the metal substrate through the adhesive, and each electrode of the semiconductor element is electrically connected to the metallized wiring layer of the insulating member through the bonding wire. A lid is joined to the upper surface of the member via a sealing material made of a brazing material or the like, and the semiconductor element is hermetically sealed inside, so that a semiconductor device as a final product is obtained.

In the package for housing the semiconductor element, the insulating member is usually made of an aluminum oxide sintered body, and the frame member to which the insulating member is fitted has the same thermal expansion coefficient as that of the insulating member. It is made of iron alloy material such as Kovar metal.

The metal base is also made of an iron alloy material such as Kovar metal in order to match the thermal expansion coefficient with the frame member brazed and attached to the metal base.

However, in the conventional package for accommodating semiconductor elements described above, the metal substrate is made of an iron alloy such as Kovar metal, and its thermal conductivity is as low as 0.040 cal / sec · cm · ° C. Since the output of such a semiconductor element is extremely large and a large amount of heat is generated, the semiconductor element is housed inside the package to form a semiconductor device, and then the semiconductor element is operated when the semiconductor element is operated. The heat generated during operation is not radiated well to the outside and is accumulated in the semiconductor element itself, resulting in a high temperature of the semiconductor element, causing thermal damage to the semiconductor element or changing the characteristics of the semiconductor element. However, there is a drawback that the semiconductor device malfunctions.

Therefore, in order to solve the above-mentioned drawbacks, a metal substrate on which a semiconductor element is fixed has a thermal conductivity of 0.9 cal / sec · cm ·
It is conceivable to use oxygen-free copper as high as ℃.

However, when this oxygen-free copper is used as a metal substrate, the heat generated during the operation of the semiconductor element is satisfactorily released to the outside through the metal substrate, and the temperature of the semiconductor element can be kept low. Coefficient of thermal expansion is 18.3
× 10 ^-6 / ℃ as high as the thermal expansion coefficient of the frame member (5.7 × 10 ^-6 / ℃ ~
(6.2 × 10 ^-6 / ° C: 800 ° C), the thermal stress caused by the difference in the thermal expansion coefficient between the frame member and the metal member when brazing and attaching it to the metal member via the brazing material such as silver solder. As a result, the metal base is largely warped, and as a result, the semiconductor element cannot be firmly fixed to the metal base, or a gap is formed between the semiconductor element and the metal base, and the heat generated by the semiconductor element is transferred to the metal base. It causes a defect that it cannot be absorbed well.

[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 attach an iron alloy frame member to a metal base having a high thermal conductivity without warping the metal base. ,
With this, the semiconductor element is firmly fixed to the metal substrate, and the heat generated by the semiconductor element is satisfactorily radiated to the outside, so that the semiconductor element can be kept at a low temperature and can be operated normally and stably for a long period of time. To provide a package for.

[0009]

According to the present invention, an iron alloy frame member fitted with an insulating member made of an aluminum oxide sintered body is attached to an outer peripheral portion of an upper surface of a metal base, and the upper surface of the metal base and the frame member are attached. A semiconductor element housing package, in which a semiconductor element is fixedly housed in a space formed by, wherein the metal base is composed of a molybdenum plate and copper plates bonded to both upper and lower surfaces of the molybdenum plate. Thickness is T
1. If the thickness of the copper plate located on the upper surface side of the semiconductor element to be fixed is T2 and the thickness of the copper plate located on the lower surface side is T3, then T2 / T1 = 1 to 7, and T3 / T2 = −T2 / 12T1 + 1. 3 to -T2 / 12
It is characterized in that it is T1 + 1.6.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 base, 2 is a frame member, and 3 is an insulating member.

The metal base 1 has a frame member on the outer periphery of its upper surface.
2 is attached via a brazing material such as silver brazing, and a semiconductor element is provided on the upper surface of the metal substrate 1 surrounded by the frame member 2.
4 is placed and fixed via an adhesive such as a brazing material.

The metal substrate 1 has a three-layer structure in which copper plates 6 and 7 are arranged on both upper and lower surfaces of a molybdenum plate 5, and a lower copper plate 7, a molybdenum plate 5, an upper copper plate 6 and a frame member 2 are sequentially laminated. At the same time, each of them is simultaneously joined with a brazing material such as silver brazing to obtain a metal base 1 having a frame member attached to the outer peripheral surface of the upper surface thereof.

The upper copper plate 6 forming the metal base 1 is heated by the molybdenum plate 5 forming the metal base 1 and the frame member 2 when the frame member 2 is mounted on the metal base 1. The lower copper plate 7 acts to absorb a part of the thermal stress due to the difference in the expansion coefficient, and the lower copper plate 7 is made of metal by the residual thermal stress between the molybdenum plate 5 and the frame member 2 constituting the metal base 1. The base member 1 has a function of canceling the occurrence of warpage, whereby the metal substrate 1 can mount the frame member 2 on its upper surface without causing warpage.

In the metal substrate 1, the thickness of the molybdenum plate 5 is T1, the thickness of the copper plate 6 located on the upper surface side where the semiconductor element is fixed is T2, and the thickness of the copper plate 7 located on the lower surface side is T2.
When it is set to 3, when T2 / T1 <1, the heat conductivity of the metal substrate 1 becomes low, and the heat generated by the semiconductor element 4 cannot be effectively removed, and when T2 / T1> 7, The coefficient of thermal expansion of the metal substrate 1 becomes large and does not match the coefficient of thermal expansion of the frame member 2. As a result, a large warp occurs in the metal substrate 1 and the semiconductor element 4 cannot be firmly fixed. Therefore, the metal base 1 is a molybdenum plate 5
Is T1, the thickness of the copper plate 6 located on the upper surface side to which the semiconductor element is fixed is T2, and the thickness of the copper plate 7 located on the lower surface side is T3, T2 / T1 = 1 to 7 is specified. ..

In addition, T3 / T2 <-T2 / 12T1 + 1.
When 3, the metal base 1 is greatly curved in a concave shape, and the metal base 1
It becomes difficult to firmly fix the semiconductor element to, and conversely, when T3 / T2> -T2 / 12T1 + 1.6,
Since the metal base 1 is largely curved in a convex shape, it becomes difficult to firmly fix the semiconductor element to the metal base 1. Therefore, the metal substrate 1 has a thickness T1 of the molybdenum plate 5, and a thickness T2 of the copper plate 6 located on the upper surface side on which the semiconductor element is fixed.
If the thickness of the copper plate 7 located on the lower surface side is T3, T3 /
T2 = -T2 / 12T1 + 1.3 to -T2 / 12T1 +
It is specified in the range of 1.6.

Copper plates 6 are formed on both upper and lower surfaces of the molybdenum plate 5,
The metal base 1 bonded with 7 also has a thermal conductivity of about 0.75.
The heat generated when the semiconductor element 4 is operated is directly conducted and absorbed by the metal substrate 1 and is well radiated into the atmosphere, because it has a thermal conductivity of up to 0.9 cal / sec · cm · ° C.
Is always kept at a low temperature, and as a result, the semiconductor element 4 can be operated normally and stably for a long period of time.

Further, the frame member 2 attached to the outer peripheral portion of the upper surface of the metal substrate 1 is made of an iron alloy material such as Kovar metal (Fe-Ni-Co alloy) and forms a space for housing the semiconductor element 4. Acts as a wall material for.

The frame member 2 is formed in a predetermined frame shape by adopting a conventionally known metal processing method such as a metal rolling processing method or a grinding processing method for an ingot (lump) of Kovar metal or the like.

The frame member 2 also has a through hole 8 formed in a part thereof, and the through hole 8 is a metallization for electrically connecting the electrode of the semiconductor element 4 housed therein to an external electric circuit. The insulating member 3 having the wiring layer 9 is fitted via a brazing material such as silver brazing.

The insulating member 3 is made of an aluminum oxide sintered body, and an organic solvent suitable for raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO) and magnesia (MgO), A solvent is added and mixed to form sludge, which is then formed into a green sheet (raw sheet) by using the doctor blade method or calendar roll method.After that, the green sheet is punched appropriately and multiple sheets are laminated. It is manufactured by firing at high temperature (about 1600 ℃).

The insulating member 3 made of the aluminum oxide sintered body has a thermal expansion coefficient similar to that of the iron alloy material forming the frame member 2. Therefore, after the insulating member 3 is fitted to the frame member 2, both Even if heat is applied, no thermal stress is generated between them due to the difference in thermal expansion coefficient, and the insulating member 3 can be fitted to the frame member 2 extremely firmly.

Further, a metallized wiring layer 9 is provided on the insulating member 3 so as to pass through the inside and outside of the frame member 2, and an electrode of the semiconductor element 4 is provided with a bonding wire 10 at one end of the metallized wiring layer 9. An external lead terminal 11 which is connected to the other end and which is directly connected to an external electric circuit is brazed.

The metallized wiring layer 9 is made of a refractory metal powder such as molybdenum or tungsten, and a metal paste obtained by adding and mixing a suitable organic solvent or solvent to the molybdenum powder or the like is used as a green sheet for the insulating member 3. The insulating member 3 is applied in a predetermined shape by printing and applying it in advance by a thick film technique such as screen printing.

On the surface of the metallized wiring layer 9, a metal material having excellent corrosion resistance such as nickel (Ni) and gold (Au) and good conductivity is formed by plating to a thickness of 1.0 to 20.0 μm. The metallized wiring layer 9 can effectively prevent oxidative corrosion of the metallized wiring layer 9 when it is attached.
The bonding wire 10 and the external lead terminal 11 can be firmly attached to the 9. Therefore, it is preferable to deposit nickel, gold or the like on the surface of the metallized wiring layer 9 to a thickness of 1.0 to 20.0 μm.

The external lead terminal 11 brazed to one end of the metallized wiring layer 9 is made of Kovar metal or 42 alloy.
External lead terminal 11 made of metallic material such as (Fe-Ni alloy)
Is connected to an external electric circuit, the electrodes of the semiconductor element 4 housed inside are electrically connected to the external electric circuit.

The external lead terminal 11 is formed into a predetermined plate shape by adopting a conventionally known metal processing method such as rolling method or punching method of an ingot (lump) of Kovar metal or the like, one end of which is silver. It is attached to the metallized wiring layer 9 of the insulating member 3 via a brazing material such as brazing. The surface of the external lead terminals 11 is 1.0 to 20.0 μm by plating with nickel, gold, etc., which has excellent corrosion resistance and good conductivity.
If it is layered on the outer lead terminal 11, the outer lead terminal 11 can be effectively prevented from being oxidized and corroded, and the outer lead terminal 11 can be firmly connected to the external electric circuit. Therefore,
The external lead terminal 11 has nickel, gold, etc. on its surface.
It is preferable that the layer is deposited to a thickness of 0 to 20.0 μm.

Thus, according to the package for accommodating semiconductor elements of the present invention, the semiconductor element 4 is fixed to the surface of the metal base 1 surrounded by the frame member 2 with an adhesive and the semiconductor element is
The electrode 4 is connected to the metallized wiring layer 9 of the insulating member 3 via the bonding wire 10, and then the lid 12 is joined to the upper portion of the frame member 2 via a sealing material such as a brazing material to form a semiconductor element. The final product is a semiconductor device by hermetically sealing 4

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the gist of the present invention.

[0030]

According to the package for accommodating semiconductor elements of the present invention, the metal base has a three-layer structure in which copper plates are joined to the upper and lower surfaces of a molybdenum plate, and the thickness of the molybdenum plate is T.
1. When the thickness of the copper plate located on the upper surface side of the semiconductor element to be fixed is T2 and the thickness of the copper plate located on the lower surface side is T3, T2 / T1 = 1 to 7 and T3 / T2 = -T2 / 12T1 + 1 to -T2 / 12T1
Since it is +1.6, when the lower copper plate, the molybdenum plate, the upper copper plate and the frame member are sequentially laminated and they are simultaneously joined by a brazing material such as silver brazing, the metal substrate does not warp. It is possible to attach the frame member to the outer peripheral portion of the upper surface of the.

Therefore, in the package for housing a semiconductor element of the present invention, since the metal base is flat, the semiconductor element can be firmly fixed to the metal base and the heat generated by the semiconductor element is transferred to the atmosphere through the metal base. It can be released well.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a semiconductor element housing package 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 base 2 ... Frame member 3 ... Insulation member 4 ... Semiconductor element 5 ... Molybdenum plate 6 ... Upper copper plate 7 ... Lower copper plate 9 ... Metallized wiring layer 11 ... External lead terminals

Claims (1)

[Claims] 1. A space formed by an upper surface of a metal base and a frame member, wherein an iron alloy frame member fitted with an insulating member made of an aluminum oxide sintered body is attached to an outer periphery of an upper surface of the metal base. A semiconductor element housing package for fixedly housing a semiconductor element, wherein the metal base is formed by joining copper plates to upper and lower surfaces of a molybdenum plate,
Further, assuming that the thickness of the molybdenum plate is T1, the thickness of the copper plate located on the upper surface side where the semiconductor element is fixed is T2, and the thickness of the copper plate located on the lower surface side is T3, then T2 / T1 = 1 to 7, and T3 / T2 = -T2 / 12T1 + 1.3 to -T2 / 12
A package for housing a semiconductor element, which is T1 + 1.6.