JPS61270262A - High heat conductive aluminum nitride sintered body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a highly thermally conductive aluminum nitride sintered body used for insulating substrates, heat sinks, etc. In particular, the present invention relates to a highly thermally conductive aluminum nitride sintered body that is easily metalized. Regarding aluminum sintered bodies.

[Conventional technology] In recent years, demands for miniaturization and improved functionality of electronic devices have become extremely large, and as a result, semiconductors are becoming more integrated, more multifunctional, faster, more output, and more reliable. is rapidly progressing. Correspondingly, the amount of heat generated from semiconductors is increasing more and more, and a substrate with a large heat dissipation ability is required to replace the conventional He9203 substrate.

Examples of substrate materials with a large heat dissipation capacity, that is, materials with high thermal conductivity include diamond, cubic BN (boron nitride),
Examples include 5iC (silicon carbide), Bed (beryria), AΩN (aluminum nitride), and Si. However, diamond and cubic BN are difficult to manufacture in a size that can be used as a substrate, and are also very expensive.

Since SiC is a semiconductor, its electrical properties such as electrical insulation and dielectric constant are inferior to AQ203, and it cannot be used as a substitute for the AΩ203 substrate. Although BeO has very excellent electrical properties, the powder generated during molding and grinding processes is toxic, so it cannot be produced domestically and must be obtained from overseas, which may lead to unstable supply. There is. 3i has poor electrical properties and low mechanical strength, so its use as a substrate material is limited. AQN has high insulation, high dielectric strength,
In addition to excellent electrical properties such as low dielectric constant, pressureless sintering can be applied, but the reality is that a metal layer cannot be formed on the required surface, and a multilayer substrate for high output has not yet been developed.

[Problems to be Solved by the Invention] As described above, AQN has poor wettability with metals, so it cannot be metalized and is difficult to use as a substrate.

Also, for example, JP-A-50-75208 and JP-A-59-4
0404, the AΩN substrate surface is oxidized and then metalized, or as in JP-A-53-102310,
First, there are known techniques such as providing a metal oxide on the surface of an AΩN substrate and then metalizing it, but although these techniques can metallize the surface of a sintered body, simultaneous firing for the purpose of multilayering, Furthermore, since a layer with relatively low thermal conductivity is interposed between the metallized metal layer and the AQN substrate, a decrease in thermal conductivity cannot be avoided. It had

[Means for solving the problems] The present invention employs the following means to solve the above problems.

The highly thermally conductive aluminum nitride sintered body of the first invention contains 100 parts by weight of aluminum nitride, borides of groups 4a, 5a, and 5a of the periodic table, and borides of groups 4a and 5a of the periodic table. One or two selected from nitrides
The total amount of more than one species of compounds in terms of metal elements is 0.1~
10 parts by weight.

Group 4a elements of the periodic table are Ti, Zr, and 1-1f, group 5a elements are V, Nb, and Ta, and group 6a elements are cr, MO, and W.

The total amount of one or more compounds selected from borides of elements in groups 48, 5a, and 6a of the periodic table and nitrides of elements in groups 4a and 5a of the periodic table in terms of metal elements. DeA
The reason why the amount is 0.1 part to 10 part to QN100 part is because if it is less than this range, the wettability of the AΩN sintered body with metal will not be improved; If the amount is higher, the high thermal conductivity of the AQN sintered body will deteriorate, and
This is because sinterability deteriorates.

Although the above-mentioned components alone are sufficient for the present invention, if necessary, a sintering aid such as Y203 or Cao may be included in an amount not exceeding 5 parts by weight per 100 parts by weight of AΩN.

Also, the relative density of this sintered body (density% relative to theoretical density)
When it is 90% or more, the high thermal conductivity effect of AQN is large, and the adhesive strength of the metallization is large.

The highly thermally conductive aluminum nitride sintered body of the second invention is obtained by adding carbides of groups 4a, 5a, and 5a of the periodic table to the first invention, and the gist thereof is that aluminum nitride is and one or two selected from borides of elements in groups 4a, 5a, and 5a of the periodic table and nitrides of elements in groups 4a and 5a of the periodic table.
More than one species of compounds and 4a of the periodic table.

It is characterized in that it consists of a total amount of 0.1 to 10 parts by weight in terms of metal elements of an amphibiotic compound with one or more compounds selected from carbides of group 5a and 6a elements.

The total amount of borides, nitrides and carbides mentioned above is AΩN100
The weight of the heaviest part is 0.1 to 10 parts by weight, as in the first invention, if it is less than this range, the wettability of the AQN sintered body with metal will not be improved; On the other hand, if the content exceeds this range, the high thermal conductivity of the /IN sintered body will deteriorate, and the sinterability will also deteriorate.

Also, in the present invention, AQN is Y2 as in the first invention.
03 or CaO in an amount of 5 parts by weight or less.

The first and second inventions are made by adding sintering aid powder to AQN powder, the aforementioned boride powder, nitride powder, or carbide powder as needed, and molding the mixture using a mold or the like. Sintering in a non-oxidizing atmosphere such as N2, Ar, NHa enterolytic gas, N2, etc., or sintering in the presence of N, B, C, etc. using a compound that ultimately becomes a boride, nitride, or carbide. It can be obtained by tying

[Function] A boride of an element in groups 4a, 5a, or 5a of the periodic table and/or a nitride of an element in groups 4a or 5a of the periodic table, and in the case of the second invention, in addition to that, 4a of the periodic table.

The carbides of group 5a and 6a elements do not form a solid solution in the AΩN particles, but instead exist between the AQN particles, that is, at the grain boundaries, and bond with the metal. Therefore, the present invention improves the wettability of AQN with the metal. I think it will improve.

Further, normally, the presence of additives at grain boundaries deteriorates thermal conductivity, but in the present invention, the above-mentioned boride, nitride, or carbide in addition to A! Although it exists at the 2N grain boundary,
It has been found that this does not impair the high thermal conductivity of AQN. The reason for this is that the added compound reacts with /IN,
Since other compounds are not generated and there is no presence that covers the entire AQN particle, the bond between AQN particles is not impaired, and while maintaining the original characteristics of AΩN, AQN
It is thought that the wettability of N with metal can be improved.

[Effects of the Invention] The highly thermally conductive aluminum nitride sintered body of the present invention comprises boride of an element of groups 4a, 5a, or 6a of the periodic table and/or nitride of an element of group 4a or 5a of the periodic table in aluminum nitride. Alternatively, by containing carbides of elements of groups 4a, '5a, and 6a of the periodic table in addition, the wettability with metals could be improved without impairing the excellent thermal conductivity of aluminum nitride.

Since the present invention does not provide a layer of oxide or the like on the substrate surface during metallization, the metallized metal layer and the AΩN substrate are directly bonded to each other, resulting in excellent bonding strength and thermal conductivity.

Furthermore, by applying the present invention to a substrate such as an IC, it is possible to obtain an electronic component with excellent heat dissipation. The substrate can be easily obtained.

Embodiment] An embodiment of the first invention and the second invention will be described.

In this example, borides, nitrides, and carbides were added to 100 parts by weight of AΩN powder with an average particle size of 1.0 μm in the specified amounts in terms of metal shown in Table 1, mixed, and mixed in ethanol for 4 hours. Raw material powders were prepared by wet mixing, and then samples for measuring density and thermal conductivity and samples for measuring wettability with metal were obtained.

The density and thermal conductivity measurements were obtained by molding the raw powder into a diameter of 11 mm and a thickness of 3 mm at a molding pressure of 1.5 ton/Cm2, followed by pressureless sintering in a nitrogen atmosphere at 1700'C for 1 hour. I followed the sample. The density was measured as a relative density (the apparent density relative to the theoretical density is % of specific gravity), and the thermal conductivity was measured using a laser flash method after hand polishing the sample to a thickness of 2 mm.

Wettability with metal was measured as adhesive strength of metallization. The adhesive strength of metallization is 30X10X of the raw material powder.
After molding to 5 mm with a molding pressure of 1.5 ton/cm2, W powder (average particle size 1
．． 0 μm) on the surface of the molded body.
mm, approximately 20 μm thick, dried, 1700 mm
After sintering at normal pressure for 1 hour in a nitrogen atmosphere, a Ni layer of 2 to 5 μm thick was formed on the surface of the sintered body by electrolytic Ni plating, and after sintering at 850°C for 10 minutes, a eutectic silver solder was applied. A 1 x 1 mm Kovar (nickel alloy containing cobalt and iron) plate was brazed at 930'C for 15 minutes using the adhesive, and the adhesive strength was measured as beer strength.

This beer strength is 0.5 mm/Se when the lead wire bonded to the Kovar plate is perpendicular to the adhesive surface.
This is the strength when the Kovar plate is peeled off from the sintered body by pulling at a speed of C.

Table 1 shows the measurement results of relative density, thermal conductivity, and beer strength. Note that samples No. 1a to 6a are No. 1 of the first invention.
b and 2b are examples of the second invention. In addition, all compositions other than those shown in Table 1 are AQN, and the unit of content in the composition is parts by weight in terms of metal relative to 100 parts by weight of AQN.

From this example, as shown in Table 1, AQN contains one or more compounds selected from borides and nitrides of groups 48, 5a, and 6a of the periodic table, or In addition, by containing 0.1 to 10 parts by weight of carbide in terms of metal, a sintered body with high thermal conductivity and high beer strength, that is, good wettability with metal, can be obtained. I understand.

In addition, 4a, 5a, 6a of the periodic table other than those shown in Table 1
Borides of group elements, and nitrides of group 4a, 5a elements of the periodic table, or in addition to borides of group 4a, 5a, 6 of the periodic table.
Similar to the samples shown in Table 1, samples using carbides of Group A elements also have a value of 0 when converted to metal with respect to AQN.
．． By containing 1 to 10 weight omega parts, a sintered body with high thermal conductivity and good wettability with metal was obtained.

The thermal conductivity of the conventional /'MIEN sintered body (relative density 99%) is 0.14 to 0.24 caQ/cm, sec.

°C, beer strength is less than 0.5 kmMmm2. or,
The thermal conductivity of AΩ2o3 (99% relative density) is 0°04
~0.07 CaΩ/cm, sec, 'C, beer strength is: 2-5k2-5k.

/IN powder (average particle size 1.0 μm>100 parts by weight of Mo
3 parts by weight of MO2B (average particle size 2.0 μm)
Adding CaO as a sintering aid to the mixture containing
Relative density, thermal conductivity, and beer strength were measured. The results are shown in Table 2.

Table 2 As can be seen from Table 2, when the amount of CaO added was up to 5 parts by weight, the sinterability, thermal conductivity, and beer strength were all the same as those without CaO, but up to 5 parts by weight. If a certain amount of Cao is added, the occurrence of precipitates on the metallized surface after firing, which are thought to be caused by the liquid phase such as Ca3AΩ208 generated during firing, becomes severe, making it impossible to measure beer strength. I understand.

Claims (1)

[Scope of Claims] 1 100 parts by weight of aluminum nitride, and one or two selected from borides of elements in groups 4a, 5a, and 6a of the periodic table and nitrides of elements in groups 4a and 5a of the periodic table.
The total amount of more than one species of compounds in terms of metal elements is 0.1~
10 parts by weight of a highly thermally conductive aluminum nitride sintered body. 2 100 parts by weight of aluminum nitride, and one or two selected from borides of elements in groups 4a, 5a, and 6a of the periodic table and nitrides of elements in groups 4a and 5a of the periodic table.
A total of 0.1 to 10% of the total weight of both compounds, including one or more compounds selected from carbides of elements in groups 4a, 5a, and 6a of the periodic table, in terms of metal elements. A highly thermally conductive aluminum nitride sintered body comprising: