JPH01313365A - Sintered body of metallized aln having high thermal conductivity and high-thermally conductive substrate - Google Patents

Abstract

PURPOSE:To provide the sintered AlN body having the high adhesive strength of the metallized layer, good electrical conductivity and high thermal conductivity by incorporating the sintered AlN body which is specified in the ratio of the quantity of solid soln. oxygen to the AlN in the metal layer consisting of W and/or Mo. CONSTITUTION:The paste formed by adding the compd. selected from groups IIa, IIIa, for example, CaO and Y2O3 as a sintering assistant and deoxidizing agent together with AlN powder to W or Mo paste is prepd. Said paste is coated on the surface of the sintered AlN body and the unsintered body thereof and is then calcined, by which the sintered body of the metallized AlN mentioned above is obtd. The metal layer of the sintered body of the metallized AlN mentioned above is required to contain the sintered AlN body having <=0.3wt.% quantity of solid soln. oxygen with respect to the AlN. The sintered body of the metallized AlN obtd. in such a manner exhibits the excellent thermal conductivity or low heat resistance and is, therefore, useful as the material for an insulating substrate, etc., in semiconductor industry.

Description

[Detailed description of the invention] <IP industry 1. FIELD OF APPLICATION> The present invention is directed to metallized AlN with excellent high thermal conductivity and having a gold n-layer consisting of W or - or both W and
This invention relates to a sintered body and a highly thermally conductive substrate using the same.

<Conventional technology and its problems> The recent progress of TSL is remarkable, and the improvement of Collection 1I4RA is remarkable. The change in IC chip size also contributes to this, and as the IC chip size increases, the amount of heat generated per package increases. For this reason, the maturity of substrate materials has come to be considered important.

In addition, the thermal conductivity of the aluminum sintered bodies conventionally used as IC substrates is not mature enough, and it is becoming impossible to cope with the increase in heat generation of IC chips. For this reason, a highly thermally conductive beryllia substrate is being considered as an alternative to the aluminum substrate, but beryllia has the drawback of being highly toxic and difficult to handle.

Aluminum nitride (AlN) is a material that has high thermal conductivity, high insulation properties, and is non-toxic, so it is widely used in the semiconductor industry.
(It is attracting attention as an insulating H material or a pack abrasive material.There are many technologies for forming a metal layer on the surface for use as 1.L plates, barrier boards, etc. for various ICs including power transistors. It has been reported.

For example, composition and metallization method for metallizing non-oxide ceramic bodies (Tokukosho (No. 32-27037), Nippon Electric Mo's aluminum nitride technology (Electronics Ceramics Magazine, November 1986 issue, p. 28) The former discloses a composition that can provide a strong bond that can be plated or brazed, as well as a metallization method using the same. [1] In addition to W, ceramics, non-oxide-based and Lamix component wood 71, that is, metallizing compositions containing AlN and metals or total flexure oxides, and NN unfired A simultaneous firing method is described in which the paste is applied to the compact and fired in a non-oxidizing atmosphere.

The latter describes a highly thermally conductive UN multilayer wiring board, in which a paste containing fine W powder and N/N is printed on an AlN green sheet, and a +? One layer was applied, the binder was removed, and pressureless sintering was performed, and the sinterability of W and electrical resistance NN sintered body were investigated depending on the amount of AlN added, and Af
It is reported that the best results were shown in blue when the N addition was ff11%, and the tensile strength was 2 Kg4 or higher, which was a practical strength of 1 minute.

There are several other cases reported, but W t > t, <
It is judged that a NN sintered body with high adhesion strength and good f can be obtained by adding AlN to the Mo paste, or by adding a metal or a total bending oxide.

Therefore, we measured the thermal resistance of an N/N base plate with a metal layer containing the same components as above, and mounted a high-power S and transistor on the metallized layer. However, the value was unexpectedly poor, and when we conducted a test, we found that the heat conduction of the metallized layer was poor.

In other words, a large amount of heat is transferred to the AlN substrate, which has high thermal conductivity.
Attempts were made to dissipate heat by mounting a metal layer on the device, but the metallized layer between the element and the substrate impairs heat conduction.
It was not possible to achieve the original high heat dissipation effect.

<Purpose of the Invention> Therefore, the present invention provides a metallized NN sintered body that has a high strength contact between metallized layers, good conductivity, and a new feature of high thermal conductivity. This is the purpose of writing.

A solution to the problem > One piece of good metallized APNvlIil with less warping and waviness and high adhesion strength! One way to achieve this is to include an AlN component in the metallized layer.1However, it is extremely insufficient to provide the metallized layer with high thermal conductivity.

The structure of the metallized layer is basically considered to be that AlN or AlN compounds were present in the voids of the sintered body of Tsuru Yota (Yo/W). 120-15014
/Ink, but J is added to the low thermal conductivity AlN, b, or a compound thereof existing in the voids as an additive, and is lowered to the end of the rod.

Therefore, it is clear that a metallized NN sintered body with excellent thermal conductivity can be obtained by surfacing a metallized layer containing a highly thermally conductive NN sintered body of the same level or higher as that of the Tsuru W111 body. This is what the inventors discovered.

That is, the present invention contains a NN sintered body in which the amount of solid dissolved oxygen in the metal layer consisting of W or both (W or ratio) is 0.3% by weight or less based on AlN. The present invention provides a highly thermally conductive metallized NN sintered body and a high thermal conductivity i/1 substrate comprising the sintered body, a semiconductor element, a lead frame, and/or a heat dissipation board.

Effect> Insulating properties such as NN sintered bodies, the thermal conduction mechanism of Lamics uses phonon conduction as one body, so defects such as pores and impurities cause phonon scattering, and the thermal conductivity is only at a low level. I can't get it. In particular, if the water resistant solid solution in the UN particles, which is considered to be the main reason for the decrease in thermal conductivity, is contained in the AfN sintered body in an amount of 0.3% by weight or more, the thermal conductivity of AfN decreases by 1.
0014/nk or less.

Therefore, in order to reduce the acid content to 0.3% by weight or less,
At the same time as WlMo is fired, the water adsorbed on the NN surface is deoxidized and AlN/! ! - It is extremely necessary to perform a precise 1 heat on a high density evil.

Since AJN itself is difficult to sinter, it is necessary to consider the effects of additives that promote the sintering of AlN.

That is, the periodicity of W or the paste as a sintering aid and IB2 acid agent together with AlN powder (Table 11a, Ila
A method of adding a compound selected from the group, such as CaO1Y20s, a method of adding carbon to 〇N powder and sintering it to deoxidize it and make a low water resistant sintered body.
Takatsumugi's method of adding low-acid AlN powder, avoiding the sintering aid remaining in the AlN sintered body with a decomposition heat oven, and adding high-purity Al
A method for obtaining a N sintered body, a method in which the sintering aid remaining on the sintered body is removed by placing it in a reducing atmosphere for a long time, and the aid penetrates into the metallized layer from the NNN root plate, that is, the base material. There is no difference in the effect of any of these methods, including the method of extracting the effect of NN powder as a sintering aid and deoxidizing agent.

In addition, for metallization methods, AP
After applying to the surface of the N sintered body and its unsintered body, good metallization can be achieved even when fired.
I'm not sure.

To give a specific example of the present invention, the metallizing composition includes AlN powder, lI3 and Y2 powder as well as W powder.
O3, CaO or Y, organic acid salt of Ca, Al
-It is particularly effective to blend a mixture of
I was caught.

Among these, the effect was particularly noticeable when 5 small parts of AlN powder and 0.05 small parts of Y stearate were used per 100 weights of W.

Despite containing a trace amount of Y, the stearin P
The a salt exists as a liquid and is extremely uniformly distributed in the W paste.
) Therefore, the effect of 1 m of stearin was clearly recognized in this invention.

A specific example of forming metallized AlN using these metallized compositions is as follows.
A paste was prepared by adding a binder consisting of a known binder such as a resin, an acrylic resin, a polyvinyl alcohol, and a known solvent such as α-tilpinol or bubucarbinol.

This paste was coated on a fusuma (AlN) green sheet, and if necessary, it was laminated and heated for 16 hours in a non-oxidizing atmosphere.
A metallized HN sintered body was obtained by firing at a temperature of 00 to 2100°C.

It has been experimentally found that the thermal conductivity of the metallized layer is more effective as the proportion of AlN in the metallized layer increases. In addition, the metallized layer of minced melon is made of AlN with Ila and I
[[It has been recognized that the presence of a group a compound leads to a positive effect.

These compounds make /VN and W%t dense, respectively.
Moreover, it is strongly sintered, and it also improves the wettability and density of the AlN substrate surface. It is thought that it is given.

However, when the proportion of the AlN sintered body in the metallized layer exceeds 30 parts by weight, AtN
The sintered body is precipitated, the metal 1 is difficult to crack, and the resistance becomes high, which is not desirable for practical use.

As described above, in order to obtain a metallized MN sintered body with high thermal conductivity, it is necessary to add 9N sintered body 61. < not only requires that the substrate has high thermal conductivity, but also that the adhering metallization layer also has high thermal conductivity.

In this invention, the AlN sintered body contained in the metallized layer is made to have high thermal conductivity, that is, the amount of acid dissolved in the UN particles is reduced to 0.3% by weight or less. A metallized AlN sintered body could be obtained.

The metallized AlN sintered body thus obtained exhibits excellent thermal conductivity and low thermal resistance, making it a popular insulating substrate or package material in the semiconductor industry.

Example IIi> The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 100 parts by weight of W powder was mixed with yttrium stearate, yttrium oxide, calcium stearate, or hJ lesium oxide shown in Table 1 and AlN powder (average particle size 0.4μ, oxygen amount 1). .41 yen%) was sufficiently mixed with an organic vehicle in 3 wood 1-1-le, and a large amount of W base was obtained.

Each of these W pastes was printed on an unsintered NN body, and the binder was removed and fired at the same time.

The sheet resistance of the W4 body of the obtained WfLa AlN sintered body was measured.

In addition, after applying NL METS-1 to the W metallized surface, N.

The treated Kovar wire was soldered and pulled in a direction perpendicular to the metallized surface to measure the adhesion strength.

Also, NL and Au plating on the W metallized surface 1! I! L
, after that, a high power transistor is installed and the forward falling light I
J.

The thermal resistance state of the substrate was measured based on the thermal resistance evaluation f[i], which was obtained by measuring the change Δ■BE due to the application of power in VB. The results of (a) are indicated by an O mark if it is of a practical level, and an X mark if it is not practical.

Furthermore, the surface condition after N, Metsu-1 treatment was examined.
Using a mirror, stains, foaming, and the precipitation state of Metsu 4Mo were evaluated, and their superiority or inferiority was indicated by ○ or X.

In addition, trial number 21 marked with * in the table is a comparative example.

Further, the addition Φ of yttrium stearate (Y stearate) and other additives is based on 100 parts by weight of W powder.

Example 2 A deposited layered AlN sintered body was obtained in the same manner as in Example 1 except that a specific powder was used in place of the W powder used in Example 1.

Table 2 shows the j-strike binding of this sintered body similar to that in Example 1.

The sample numbers marked with * in the human body are comparative examples.

Table 2 As is clear from the results of Examples 1 and 2 above, in order to have a metallized AlN sintered body with high thermal conductivity, that is, a metallized layer with low thermal resistance, it is necessary to AlN present in
It is necessary that the solid solution water resistance of the sintered body is 0.3% or less.

In addition, if the sheet resistance, tensile strength, surface condition, etc. of this sintered body are evaluated, it is important that the hanging part during the addition of AlN should be Φ or less than 100 cm of W or heavy metal. Admitted.

<Effects of the Invention> As described above, the metallized AlN sintered body that will become the north gate exhibits excellent thermal conductivity and low thermal resistance, and is extremely popular as an insulation 4A material or packaging material in the half-and-half industry. Therefore, it is expected that it will be effective.

Claims (4)

[Claims] (1) The amount of solid dissolved oxygen in the metal layer consisting of W or Mo alone or both W and Mo is 0.3 with respect to AlN.
A highly thermally conductive metallized Al sintered body, characterized in that it contains an AlN sintered body of not more than % by weight. (2) The content of AlN is 3 parts by weight per 100 parts by weight of the metal layer consisting of W or Mo alone or both W and Mo.
The highly thermally conductive metallized Al sintered body according to claim 1, wherein the content is 0 parts by weight or less. (3) Group IIa or III of the periodic table in the AlN sintered body
The highly thermally conductive metallized AlN sintered body according to claim 1, which contains an oxide of a group a element. (4) A highly thermally conductive substrate comprising a metallized AlN sintered body, a semiconductor element, a lead frame, and/or a heat dissipation substrate.