JP2735749B2 - Aluminum nitride sintered body having metallized metal layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum nitride sintered body having a metallized metal layer.

[0002]

2. Description of the Related Art Conventionally, ceramics, especially oxide-based ceramics represented by alumina, have excellent properties such as electrical insulation and chemical stability. , Resistors, capacitors, etc. are often used for circuit boards, etc. on which the oxide-based ceramics are used. Semiconductor element storage packages and circuit boards using such oxide ceramics have a metallized metal layer as a circuit wiring conductor on the surface of the ceramic body. Many are adhered and joined.

The metallized metal layer on the surface of a ceramic body made of such an oxide ceramic usually has an average particle size of 2.0 μm when the ceramic body is made of an alumina sintered body.
An organic solvent is added to a powder composed of about molybdenum-manganese or the like, and a paste obtained by adding a solvent is applied to the surface of the alumina-based sintered body by a screen printing method. C. and a part of the glass component interposed between the alumina crystals of the alumina-based sintered body between powder particles such as molybdenum-manganese powder is transferred, and the alumina crystal and the molybdenum-manganese powder etc. And adhered to the surface of the alumina-based sintered body.

However, in recent years, the density and integration of semiconductor devices have been rapidly increasing, and the amount of heat generated when the semiconductor devices are operating has become extremely large.
Therefore, when this semiconductor element is housed and mounted in the above-mentioned conventional semiconductor element housing package or circuit board, the thermal conductivity of the alumina-based sintered body used for the package or circuit board is as low as about 20 W / mK. Therefore, heat generated during operation of the semiconductor element through the alumina sintered body cannot be satisfactorily dissipated into the atmosphere. As a result, the temperature of the semiconductor element becomes high due to the heat generated by the element itself. This has the drawback of causing thermal destruction or causing a thermal change in characteristics to cause a malfunction.

Therefore, in order to solve the above-mentioned drawbacks, the thermal conductivity is changed to oxide ceramics such as alumina-based sintered bodies.
It is conceivable to use an aluminum nitride sintered body that is extremely easy to conduct heat of 80.0 W / m · K or more.

[0006]

However, the aluminum nitride sintered body has a low glass component interposed between the aluminum nitride crystals and has poor wettability between the aluminum nitride crystal and the metal. Even if a metallized metal layer made of molybdenum-manganese powder or the like is bonded to the surface of the body, the bonding strength is extremely weak, and it has a drawback that it cannot be used as a package for storing semiconductor elements or a circuit board.

[0007]

SUMMARY OF THE INVENTION The present inventor has conducted various experiments in view of the above-mentioned drawbacks. As a result, a metallized metal layer containing a predetermined amount of manganese oxide powder, silicon oxide powder and yttrium aluminum garnet powder in molybdenum powder was used. Then, it was found that the metallized metal layer can be joined to the aluminum nitride sintered body by increasing the joining strength.

According to the present invention, based on the above findings, the bonding strength between the metallized metal layer and the aluminum nitride sintered body is high,
An object of the present invention is to provide an aluminum nitride sintered body having a metallized metal layer that can be suitably used for a package for housing a semiconductor element, a circuit board, and the like.

[0009]

SUMMARY OF THE INVENTION The present invention provides a molybdenum powder.
70.0 to 90.0% by weight, manganese oxide powder 3.0 to 20.0
A metallized metal layer containing, by weight, 3.0 to 15.0% by weight of silicon oxide powder and 1.0 to 10.0% by weight of yttrium aluminum garnet powder is bonded to the aluminum nitride sintered body.

The molybdenum powder used in the metallized metal layer according to the present invention constitutes the main component of the metallized metal layer. If the amount is less than 70.0% by weight, the sintering of the molybdenum powder is alienated and the metallized metal layer itself is not sintered. As the mechanical strength decreases, the sheet resistance of the metallized metal layer increases greatly, making it unusable for packages for storing semiconductor elements. If it exceeds 90.0% by weight, the bonding strength between the metallized metal layer and the aluminum nitride sintered body is exceeded. Becomes extremely weak and cannot be used for packages for housing semiconductor elements. Therefore, the amount of molybdenum powder is specified in the range of 70.0 to 90.0% by weight.

The molybdenum powder has a particle size of 0.3.
If it is less than μm, the surface energy of the molybdenum powder becomes large and it becomes easy to form agglomerates.If it exceeds 3.0 μm, the particle size of the molybdenum powder becomes large and the contact area between adjacent powders becomes small. Also, the sheet resistance of the metallized metal layer tends to be large.

Therefore, in order to reduce the sheet resistance of the metallized metal layer, the particle size of the molybdenum powder should be 0.3 to
It is preferable to set the range to 3.0 μm.

The manganese oxide powder, the silicon oxide powder and the yttrium aluminum garnet powder contained in the metallized metal layer of the present invention are all glasses for strongly bonding molybdenum powder as a main component to an aluminum nitride sintered body. When the manganese oxide powder content is less than 3.0% by weight, the silicon oxide powder content is less than 3.0% by weight, and the yttrium aluminum garnet powder content is less than 1.0% by weight, the glass component Is not sufficiently formed, the metallized metal layer cannot be firmly joined to the aluminum nitride sintered body, the content of manganese oxide powder exceeds 20.0% by weight, and the content of silicon oxide powder is 15.0% by weight. % And the content of yttrium aluminum garnet powder exceeds 10.0% by weight, molybdenum as the main component Sintering of down powder is alienated,
The mechanical strength of the metallized metal layer itself is reduced, and the sheet resistance of the metallized metal layer is greatly increased. Therefore,
The content of the manganese oxide powder is 3.0 to 20.0% by weight.
The content of silicon oxide powder is 3.0 to 15.0% by weight, and the content of yttrium aluminum garnet powder is 1.0 to 1.0% by weight.
To 10.0% by weight.

When the manganese oxide powder, silicon oxide powder, and yttrium aluminum garnet powder contained in the metallized metal layer have a particle size exceeding 10 μm, the contact area between the powders forming the glass component becomes small, and the glass component is formed. Therefore, it tends to be difficult to firmly join the metallized metal layer to the aluminum nitride sintered body. Therefore, in order to firmly join the metallized metal layer to the aluminum nitride sintered body, it is preferable that the manganese oxide powder, the silicon oxide powder, and the yttrium aluminum garnet powder have a particle size of 10 μm or less.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows an example in which an aluminum nitride sintered body having a metallized metal layer of the present invention is applied to a package for housing a semiconductor element, 1 is an insulating base made of aluminum nitride sintered body, and 2 is a lid. is there. The insulating base 1 and the lid 2 constitute a container 3 for housing the semiconductor element 4.

The insulating base 1 has a mounting portion for mounting and fixing the semiconductor element 4 at the center of the upper surface thereof. The semiconductor element 4 is provided with an adhesive such as glass or resin on the semiconductor element mounting portion. It is fixed by bonding.

The insulating substrate 1 has a high thermal conductivity of the aluminum nitride sintered body constituting it of 80.0 W / m · K or more and is easy to conduct heat, so that the semiconductor substrate is placed on the semiconductor element mounting portion of the insulating substrate 1. When the element 4 is attached and activated, the insulating base 1
Can directly conduct and absorb the heat generated by the semiconductor element 4 and satisfactorily dissipate the absorbed heat into the atmosphere. It will not change and will not malfunction.

The insulating substrate 1 made of the aluminum nitride sintered body is prepared, for example, by adding a powder such as yttrium oxide or calcia as a sintering aid and a suitable organic solvent and solvent to aluminum nitride powder as a main raw material. The raw material powder obtained by mixing is filled in a predetermined mold and pressed at a certain pressure to form a molded body, and thereafter, the molded body is manufactured by firing at a high temperature of about 1800 ° C. You.

A plurality of metallized metal layers 5 are formed on the insulating substrate 1 from the periphery of the semiconductor element mounting portion to the outer peripheral end thereof, and the metallized metal layer 5 is provided around the semiconductor element mounting portion of the metallized metal layer 5. Electrodes are electrically connected via bonding wires 6, and external lead terminals 7 electrically connected to an external electric circuit are brazed to a portion led out to the outer peripheral end via a brazing material 8 such as silver brazing. Be worn.

The metallized metal layer 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 4 to the external lead terminal 7, and is composed of 70.0 to 90.0% by weight of molybdenum powder, 3.0 to 20.0% by weight of manganese oxide powder, Silicon oxide powder 3.0
To 15.0% by weight, and 1.0 to 10.0% by weight of yttrium aluminum garnet powder.

The metallized metal layer 5 is prepared by adding a manganese oxide powder, a silicon oxide powder, a yttrium aluminum garnet powder and an appropriate organic solvent and a solvent to a molybdenum powder to form a metal paste, and the aluminum paste is made of aluminum nitride. A predetermined pattern is printed on the surface of the insulating substrate 1 made of the union by a conventionally well-known screen printing method, and then the coated substrate is reduced to about 1500 in a reducing atmosphere.
By baking at a temperature of ° C., the insulating substrate 1 is adhered and formed at a predetermined position. In this case, since the metallized metal layer 5 contains a predetermined amount of the manganese oxide powder, the silicon oxide powder, and the yttrium aluminum garnet powder in the molybdenum powder, the metallized metal layer 5 is extremely strongly bonded to the insulating base 1.

The external lead terminals 7 brazed to the metallized metal layer 5 serve to connect the semiconductor element 4 housed therein to an external electric circuit.
Is connected to an external electric circuit, so that the semiconductor element 4 housed inside is electrically connected to the external electric circuit via the metallized metal layer 5 and the external lead terminal 7.

The external lead terminal 7 is made of Kovar metal (Fe-
It is made of an iron alloy-based metal material such as Ni-Co alloy or 42 alloy (Fe-Ni alloy), and is brazed to the metallized metal layer 5 via a brazing material 8 such as silver brazing.

The external lead terminal 7 is made of iron 51.0 to 6
4.0% by weight, nickel 29.0-34.0% by weight and cobalt
When formed from an alloy of 7.0 to 15.0% by weight, its coefficient of thermal expansion is close to the coefficient of thermal expansion (4.2 to 4.7 × 10 ⁻⁶ / ° C.) of the aluminum nitride sintered body constituting the insulating substrate 1.
0 × 10 ⁻⁶ / ° C. (20 to 400 ° C.), and when the external lead terminals 7 are brazed to the metallized metal layer 5 adhered to the insulating base 1, the space between the insulating base 1 and the external lead terminals 7 No large thermal stress is generated due to the difference between the two thermal expansion coefficients, and the external lead terminals 7
Can be very firmly brazed. Therefore, the external lead terminal 7 has a thermal expansion coefficient of 4.0 to 5.0 ×
An alloy of 51.0 to 64.0% by weight of iron, 29.0 to 34.0% by weight of nickel, and 7.0 to 15.0% by weight of iron to firmly braze to the metallized metal layer 5 of the insulating substrate 1 at 10 ^-6 / ° C (20 to 400 ° C) It is preferable to form it.

Thus, in the above-mentioned package for housing a semiconductor element, the semiconductor element 4 is bonded and fixed to the semiconductor element mounting portion of the insulating base 1 with an adhesive, and each electrode of the semiconductor element 4 is bonded to the metallized metal layer 5 with the bonding wire 6. And then electrically connected to the upper surface of the insulating base 1.
2 are joined with a sealing material such as glass or resin, and the container 3 is hermetically sealed to provide a semiconductor device as a product.

(Experimental Example) Next, the operation and effect of the present invention will be described based on the following experimental examples. First, particle size as starting material
A manganese oxide powder, a silicon oxide powder and a yttrium aluminum garnet powder (hereinafter abbreviated as YAG) having a particle size of 2 μm are added to a 0.8 μm molybdenum powder in Tables 1 and 2.
, And an organic solvent and a solvent are added and mixed with the mixture and kneaded with a kneader for 48 hours to obtain a metallized metal layer paste sample.

Sample No. 18 is a comparative sample for comparison with the product of the present invention, and is a paste for a metallized metal layer which is generally used in the past and is composed of molybdenum powder having a particle size of 0.8 μm and manganese powder.

Using the metallized metal layer paste sample thus obtained, the surface of the aluminum nitride sintered body was
Twenty 1.5 mm square, 20 μm thick patterns are printed and applied by screen printing, and then this is placed in a reducing atmosphere for about 1500
Then, the metallized metal layer is adhered and bonded to the surface of the aluminum nitride sintered body.

Next, the metallized metal layer is
Square, length 40.0mm iron 51.0-64.0% by weight, nickel 29.0
One end of a metal column consisting of 34.0% by weight and 7.0-15.0% by weight of cobalt is brazed through a silver braze (silver: 72.O% by weight, copper: 28.0% by weight), and then the metal column is brazed. The end opposite to the portion was pulled in the vertical direction, the tensile strength when the metallized metal layer was peeled off from the aluminum nitride sintered body was examined, and the average value was calculated as the bonding strength of the metallized metal layer.

When a metal pillar is brazed to the metallized metal layer, a thickness of 1. mm is applied to the outer surface of the metallized metal layer.
A 5 μm nickel plating layer was deposited.

The above results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

As can be seen from the above experimental results, the conventional metallized metal layer has an extremely weak bonding strength of 0.4 kg / mm ² with the aluminum nitride sintered body, whereas the product of the present invention has 2.0 kg / mm ² or more, and the metallized metal layer is firmly adhered and bonded to the aluminum nitride sintered body.

In particular, the metallized metal layer is made of molybdenum powder.
When formed of 75 to 85% by weight, manganese oxide powder 5 to 10% by weight, silicon oxide powder 5 to 10% by weight, and yttrium aluminum garnet powder 2 to 5% by weight, the joining strength of the metallized metal layer to the aluminum nitride sintered body Is 5Kg /
mm ² or more, so that the metallized metal layer is extremely strongly adhered and bonded to the aluminum nitride sintered body.

Accordingly, the aluminum nitride sintered body having the metallized metal layer according to the present invention can be very suitably used for a package for accommodating a semiconductor element and a circuit board for accommodating a semiconductor element.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment in which an aluminum nitride sintered body having a metallized metal layer of the present invention is applied to a semiconductor element housing package for housing a semiconductor element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base consisting of aluminum nitride sintered body 2 ... Lid 5 ... Metallized metal layer 7 ... External lead terminal

Claims (1)

(57) [Claims] A manganese oxide powder of 3.0 to 20.0% by weight and a silicon oxide powder of 3.0 to 90.0% by weight of molybdenum powder.
An aluminum nitride sintered body having a metallized metal layer, wherein a metallized metal layer containing from 1 to 15.0% by weight and from 1.0 to 10.0% by weight of yttrium aluminum garnet powder is joined to an aluminum nitride-based sintered body.