JPH11335822A - Nialmo sputtering target and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sputtering characteristics and to also improve the uniformity of a formed film by using a sintered compact having a uniform compsn. consisting of Ni, Al and Mo as principal components and the balance inevitable impurities. SOLUTION: Nickel powder of 3-150 μm average particle diameter, Al powder of 3-150 μm average particle diameter and Mo powder of <=5 μm average particle diameter are mixed in a ball mill or the like and the powdery mixture is sintered with a pressure sintering apparatus such as a hot press at prescribed temp. and pressure in vacuum or in an inert gaseous atmosphere. A dense sintered compact having >=100% relative density is preferably used as the objective sputtering target. In order to attain the high relative density, the powdery mixture is preferably sintered by holding at 1,000 to <1,300 deg.C and >=200 kg/cm<2> pressure for >=2 hr. The objective sintered compact having a structure contg. Mo particles dispersed in an Ni-Al alloy matrix is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a NiAlMo sputtering target used for forming a corrosion resistant film, an optical interference film, a conductive film for forming a wiring of an LCD by a sputtering method, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, alloy thin films containing high melting point Mo (molybdenum) have been used as functional thin films such as corrosion resistant films, optical interference films, and conductive films for wiring of LCDs. From the viewpoint of the uniformity of the resulting film, the sputtering target used for forming these functional thin films is also preferably an alloy target corresponding to the composition or a composite target in which each constituent element is finely dispersed.

Conventionally, as a method of manufacturing such a sputtering target, a melting method, a powder metallurgy method, and the like are known.

[0004] However, when a target containing a high melting point element such as Mo is produced by a melting method, a high temperature is required for melting the raw material, which is not preferable from the viewpoint of apparatus cost and energy consumption. In addition, voids typified by shrinkage cavities may remain inside the target manufactured by the melting method, and these voids cause an abnormal discharge or the like during sputtering. Normally, these voids can be removed by plastic working such as forging and rolling.However, when the intermetallic compound to be produced is a brittle alloy system, the internal voids must be removed by plastic working such as forging or rolling. Is impossible.

On the other hand, with respect to the powder metallurgy method, as disclosed in, for example, JP-A-6-279910, Mo-
By adding Al alloy powder and hot isostatic pressing (HIP) or cold isostatic pressing (CIP) or molding and extruding and then sintering at high temperature, NiAlMo alloy with high sintering density can be manufactured. It is known that this is possible. However, in such a method, Ni-Al
The sintering temperature is 1300 ° C. to 16
There was a problem that the temperature was as high as 00 ° C.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide NiAl which contains a high melting point metal Mo and a low melting point metal Al and has a brittle intermetallic compound produced.
With respect to a NiAlMo sputtering target for forming a Mo alloy film, the problems in the prior art as described above are solved, the sputtering characteristics are good, and the uniformity of the obtained film is good, and the constituent elements are finely dispersed. Another object of the present invention is to provide a NiAlMo sputtering target made of a dense sintered body and a manufacturing method capable of manufacturing the target with a simple process.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that Ni, Al,
After sufficiently mixing each of the Mo metal powders, by pressing and sintering with a hot press device or the like, it has been found that a sputtering target composed of a dense sintered body in which constituent elements are finely dispersed and easily obtained can be easily obtained. .

Conventionally, when mixing and sintering metal powders such as Mo and Al whose melting points are greatly different from each other, a metal having a low melting point is dissolved first, and a uniform and dense sintered body can be obtained. Although it was thought that there was no such problem, by coexisting Ni which easily reacts with Al to form an intermetallic compound having a relatively high melting point, there is no possibility that Al is dissolved and flows out, and NiAlMo is produced by a simple process. The inventors have found that a sputtering target can be manufactured, and have completed the present invention. In other words, by mixing Al powder and Ni powder with Mo powder having a sufficiently small particle size and sintering under pressure,
Al and Ni are alloyed during pressure sintering, and a dense alloy phase can be formed between fine Mo particles, making it possible to produce a sputtering target composed of a sintered body having a high density and a uniform composition. I found something.

That is, the sputtering target of the present invention is a NiAlMo sputtering target characterized by comprising Ni, Al and Mo as main components, the remainder being unavoidable impurities, and a sintered body having a uniform composition. is there. Further, the sputtering target of the present invention is a NiAlMo sputtering target formed of a sintered body having a structure in which Ni and Al are alloyed to form a substrate and fine Mo particles are dispersed in the substrate. The average particle size of the Mo particles dispersed in the substrate is 5 μm.
m or less. The relative density obtained by assuming the theoretical density of the sintered body used for the sputtering target of the present invention as a volume ratio weighted average of the densities of the individual constituent elements of Ni, Al and Mo is 100%.
A dense sintered body as described above is preferable.

Further, the method of manufacturing a sputtering target according to the present invention is characterized in that, after mixing the respective metal powders of Ni, Al and Mo, the mixture is sintered under pressure.
This is a method for producing a sputtering target, preferably using Mo powder having an average particle size of 5 μm or less.
After mixing the respective metal powders of i, Al, and Mo, the mixture is subjected to pressure sintering at a temperature of 1000 ° C. or more and less than 1300 ° C. and a pressure of 200 kg / cm ² or more for 2 hours or more, Conditions under which a sintering effect is obtained, for example, 950 ° C.
It is preferable to perform pressure sintering at the above temperature and at a pressure of 1.5 ton / cm ² or more for 2 hours or more.

Hereinafter, the present invention will be described in detail.

The Ni powder and Al powder used in the present invention preferably have an average particle size of 3 to 150 μm in order to achieve the fine structure of the sputtering target of the present invention. Mo powder having an average particle diameter of 5 μm or less is used. These metal powders are sufficiently mixed by a powder mixing device such as a ball mill, a V-shaped blender, a cross mixer, etc. to obtain a mixed powder. Next, this mixed powder is heated in a vacuum or an inert gas atmosphere in a pressure of 500 to 120 using a pressure sintering apparatus such as hot press or HIP.
Sintering is performed by applying a pressure of 100 kg / cm ² or more at a temperature of 0 ° C. The sintered body thus obtained has a relative density of 60% or more and a fine structure with an average particle size of 150 μm or less.

The density of the sintered body can be controlled by the sintering temperature, the sintering pressure, and the sintering time. Any of the operations of increasing the length is effective in improving the density of the sintered body.

In general, by using a sputtering target made of a high-density sintered body, it is possible to prevent a splash at the time of sputtering caused by, for example, an included gas or the like, to suppress the generation of particles, and to reduce the time required for using the target. Although good characteristics as a target can be obtained, for example, it can be lengthened, the NiAlM of the present invention can be obtained.
o It is preferable to use a dense sintered body having a relative density of 100% or more in the sputtering target.

A dense sintered body having a relative density of 100% or more is
For example, a sintering temperature of 1000 ° C. or more and a sintering pressure of 200
It can be obtained by holding at kg / cm ² or more for 2 hours or more. Alternatively, it can be obtained by a combination of a sintering temperature, a sintering pressure, and a holding time at which a sintering effect equivalent to or more than that is obtained. In other words, even if the sintering temperature is 1000 ° C
By increasing the sintering pressure even if it is less than 1, it is possible to obtain a dense sintered body having a relative density of 100% or more. Similarly, by increasing the holding time, the sintering temperature can be increased to 100.
Even if the temperature is lower than 0 ° C., it is possible to obtain a dense sintered body having a relative density of 100% or more. For example, if the sintering pressure is 1.
The sintering temperature of 95 tons / cm ² or more
A dense sintered body having a relative density of 100% or more can be obtained at 0 ° C. for 2 hours. The sintering temperature is 130
When the temperature is 0 ° C. or higher, a liquid phase may be generated, and the sintering temperature is set at 13 ° C. from the viewpoint of equipment cost and energy consumption.
Preferably, the temperature is lower than 00 ° C.

Here, the following formula defines the relative density used in the present invention.

Relative density (%) = (bulk density / volume average density) × 100 Here, the bulk density (g / cm ³ ) is, for example, an actually measured value calculated from the dimensions and weight of a manufactured target. .
Further, the volume average density (g / cm ³ ) is a value obtained by averaging the intrinsic densities of the respective elements constituting the target by weighting the volume ratio in the target composition (volume ratio weighted average value). For example, element A and element B are a (vol%) and b (v
ol%) (where a + b = 100 (%)),
Its volume average density is represented by (aρ _A + bρ _B ) / 100. Here, ρ _A and ρ _B represent the specific density of the element A and the specific density of the element B, respectively.

In the present invention, the relative density may exceed 100%.
This is due to the fact that the bulk density of the alloy consisting of 1 is much higher than the theoretical density expected from the weighted average of the volume ratios of Ni alone and Al alone.

According to the method for manufacturing a NiAlMo sputtering target of the present invention, Ni and Al begin to form an alloy such as α-Ni or β-NiAl at a low temperature of about 500 ° C., but the sintering temperature is further increased. Even Ni,
Al element hardly reacts with Mo, and Ni-
A sintered body having a structure in which Mo particles are dispersed in an Al alloy substrate is obtained. Therefore, the obtained sintered body has a uniform and fine structure corresponding to the particle size of the Mo powder added first. In particular, the average particle size of the Mo powder added first is 5 μm.
By performing the following, an abnormal discharge is less likely to occur during sputtering, and a sputtering target having good uniformity of the obtained film and having a uniform and fine structure can be obtained.

[0020]

(Example 1) As a raw material powder, the average particle size was 5
μm Ni powder and Mo powder with an average particle size of 150μ
m of Al powder was used. Ni and Al
Was weighed so as to have a composition (composition A) having an atomic ratio of 3: 1 and the balance of Mo, and mixed by a ball mill for 16 hours. This mixed powder is filled in a carbon mold and heated at a temperature of 550 ° C. to 1150 ° C., 200 k
FIG. 1 shows the density of the sintered body obtained when the pressure was maintained at a pressure of g / cm ² for 2 hours. From FIG. 1, it can be seen that a dense sintered body having a relative density of 100% or more can be obtained at 1000 ° C. or more.

The cross section of the sintered body having a relative density exceeding 100% was mirror-polished and its structure was observed by EPMA. The following results were obtained for the sintered body having a relative density exceeding 100%. . As an example of the observation results, FIGS. 2 and 3 show a state of a sintered body having a relative density of 108.5% obtained at a sintering temperature of 1150 ° C. From the secondary electron beam image shown in FIG. 2, it can be seen that this sintered body is a dense sintered body without pores. 3A to 3C, Ni, Al,
From the characteristic X-ray image of each element of Mo (the white part indicates the concentrated part of the element), this sintered body alloys Ni and Al to form a substrate, and the average particle size in the substrate is 5 μm or less. Mo
It can be seen that the particles have a uniformly dispersed structure. further,
From the results of the X-ray diffraction measurement of this sintered body shown in FIG. 4, it can be seen that this alloy of Ni and Al is a mixed phase of α-Ni phase and β-NiAl phase.

This sintered body was processed into a predetermined shape and joined to a backing plate to obtain a sputtering target.

Example 2 In the same manner as in Example 1, Ni powder and Mo powder having an average particle diameter of 5 μm and Al powder having an average particle diameter of 150 μm were used as raw material powders. The composition was weighed so that the composition was such that the atomic ratio of Al was 2: 1 and the balance was Mo (composition B), and the mixture was mixed by a ball mill for 16 hours. This mixed powder is filled in a carbon mold and heated at 550 ° C. to 1150 ° C.
FIG. 1 shows the density of the sintered body obtained when the temperature was maintained at a temperature of 200 ° C. and a pressure of 200 kg / cm ² for 2 hours. Figures 1 to 10
It is understood that a dense sintered body having a relative density of 100% or more can be obtained at a temperature of 00 ° C. or more.

The cross section of the sintered body having a relative density exceeding 100% was mirror-polished and its structure was observed by EPMA. As in Example 1, the sintered body was a dense sintered body having no pores. It was found that Ni and Al were alloyed to form a substrate, and the substrate had a structure in which Mo particles having an average particle size of 5 μm or less were uniformly dispersed. FIG. 4 shows the results of X-ray diffraction measurement of the sintered body obtained at a sintering temperature of 1150 ° C. From the measurement results, it can be seen that the alloy of Ni and Al has an α-Ni phase and a β-NiAl phase. It is a mixed phase, and from the comparison with Example 1, the quantitative ratio is Ni and Al added first.
It can be seen that it corresponds to the quantitative ratio of.

As in Example 1, the obtained sintered body was processed into a predetermined shape and joined to a backing plate to obtain a sputtering target.

(Example 3) A mixed powder having the composition A was prepared in the same procedure as in Example 1, and the mixed powder was filled in a rubber mold and then subjected to pressure molding by CIP. The obtained compact was sintered by HIP at a sintering temperature of 950 ° C. and a sintering pressure of 1.5 t.
The sintering was performed at on / cm ² for 2 hours. As shown in Table 1, sintering temperature 1000 ° C, sintering pressure 200kg / c
m ² , the relative density of the sintered body obtained after holding for 2 hours was 102.9%, but the increase in the sintering pressure caused the relative density of the obtained sintered body to be 107.5%. Rose.

[0027]

[Table 1]

(Example 4) A mixed powder of the A composition was prepared in the same procedure as in Example 1, and the temperature was set to 1000 ° C and 200 kg / cm ² by a hot press device in the same manner as in Example 1.
For 5 hours. Due to the extension of the holding time, the relative density of the obtained sintered body was 104.7% as shown in Table 1.
Rose.

[0029]

According to the present invention, Mo, which is a high melting point metal, is used.
And a low-melting-point metal, Al, and also a NiAlMo alloy in which a brittle intermetallic compound is formed.
A sputtering target can be easily obtained.
Furthermore, since the NiAlMo sputtering target of the present invention is formed of a dense and high-density sintered body in which the constituent elements are finely dispersed, abnormal discharge is unlikely to occur during sputtering, and a thin film with good uniformity can be formed. At the same time, splash at the time of sputtering caused by an included gas or the like can be prevented, generation of particles can be suppressed, and the target can be used for a longer time.

Therefore, the NiAlMo sputtering target of the present invention is suitable as a sputtering target for forming a functional thin film such as a corrosion-resistant film, an optical interference film, and a conductive film for forming a wiring of an LCD.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the sintering temperature and the relative density in Examples 1 and 2.

FIG. 2 is a view showing an example of a secondary electron beam image of a sintered body in Example 1.

FIG. 3 is a view showing an example of a characteristic X-ray image of a sintered body in Example 1. (A) Ni characteristic X-ray image, (b) Al characteristic X-ray image, (c) Mo characteristic X-ray image

FIG. 4 is a view showing the measurement results of the sintered bodies in Example 1 and Example 2 by X-ray diffraction.

Claims (6)

[Claims] 1. A NiAlMo sputtering target comprising Ni, Al and Mo as main components, the remainder being inevitable impurities, and a sintered body having a uniform composition. 2. The N alloy according to claim 1, wherein Ni and Al are alloyed to form a matrix, and the sintered body has a structure in which fine Mo particles are dispersed in the matrix.
iAlMo sputtering target. 3. The N particle according to claim 2, wherein the Mo particles dispersed in the substrate have an average particle size of 5 μm or less.
iAlMo sputtering target. 4. A relative density of a sintered body obtained by assuming a theoretical density as a volume ratio weighted average value of densities of individual constituent elements of Ni, Al and Mo is 100% or more. The NiAlMo according to any one of claims 1 to 3,
Sputtering target. 5. The method for producing a NiAlMo sputtering target according to claim 1, wherein the respective metal powders of Ni, Al, and Mo are mixed and then sintered under pressure. 6. After mixing each metal powder of Ni, Al, and Mo, a temperature of 1000 ° C. or more and less than 1300 ° C. and 200
pressure sintering at a pressure of at least kg / cm ^{2 for at} least 2 hours,
5. The method for producing a NiAlMo sputtering target according to claim 1, wherein pressure sintering is performed under a condition that achieves a sintering effect equal to or higher than the above condition. 6.