KR20200112715A - Mo alloy target material and method for manufacturing the same - Google Patents

Abstract

An object of the present invention is to provide a Mo alloy target material which can suppress deformation of the target material and abrasion and fracture of a tip of a cutting tool in handling such as chucking and bonding, and suppress abnormal discharge during sputtering at the same time. To this end, the Mo alloy target material, according to the present invention, contains 10-49 atom% of Ni, 1-30 atom% of Ti, and the balance Mo and unavoidable impurities, wherein the total amount of Ni and Ti is 50 atom% or less. The Mo alloy target material has a Vickers hardness of 340-450 HV, and the standard deviation of the Vickers hardness measured at 9 measurement points is 20 HV or less.

Description

Mo alloy target material and method for manufacturing the same

The present invention relates to, for example, a Mo alloy target material for forming an electrode or a thin wiring for an electronic component, and a method of manufacturing the same.

Flat display devices such as electrophoretic displays (Flat Panel Display: hereinafter referred to as FPD) and thin-film electronic components such as various semiconductor devices, thin-film sensors, and magnetic heads have low electrical resistance ( Hereinafter, it is also referred to as "low resistance.") A thin wiring film is required. For example, FPD has a large screen, high definition, and high-speed response, and a low resistance is required for the thin wiring. In addition, in recent years, new products such as touch panels that add operability to FPDs and flexible FPDs using resin substrates have been developed.

The thin film transistor (Thin Film Transistor: hereinafter referred to as TFT) used as a driving element of the FPD needs to have a lower resistance, and therefore, research is being conducted to change the wiring material from Al to Cu with lower resistance than the conventional Al. .

At present, an amorphous Si semiconductor film is used for TFT, and when Cu, which is a wiring film, directly contacts Si, thermal diffusion by a heating process during TFT manufacturing deteriorates the characteristics of the TFT. For this reason, a laminated wiring film made of Mo or Mo alloy having excellent heat resistance as a barrier film is used as a cap film between Cu and Si.

In addition, from the amorphous Si semiconductor film to date, application of a transparent semiconductor film using an oxide capable of realizing a faster response is being conducted. In the wiring thin film of these oxide semiconductors, a wiring film made of Cu and a Mo or Mo alloy A laminated wiring film having a structure in which an underlying film or a cap film made of is laminated has been studied. For this reason, the demand for a thin film made of a Mo alloy used for forming these laminated wiring films is increasing.

Further, a Mo-Ni-Ti alloy has been proposed as a thin Mo alloy film having high moisture resistance and suitable for mobile devices and vehicle-mounted devices.

On the other hand, as a method of forming the aforementioned Mo alloy thin film, a sputtering method using a sputtering target material (hereinafter, also simply referred to as "target material") is optimal. The sputtering method is one of the physical vapor deposition methods. Compared to other vacuum vapor deposition or ion plating, it is a method that can stably form a Mo alloy thin film on a large area, and at the same time, even if the alloy has many additive elements as described above, composition fluctuation is small. It is an effective method for obtaining an excellent Mo alloy thin film.

As a method of obtaining the target material made of the Mo-Ni-Ti alloy described above, for example, in Patent Document 1, Mo powder and at least one Ni alloy powder are mixed, or Mo powder, Ni alloy powder and Ti powder are mixed. A method of machining a sintered compact obtained by pressing sintered mixed powder is proposed.

Japanese Patent Publication No. 2014-177696

When a target material is produced by pressing and sintering the Mo powder disclosed in Patent Document 1, a mixture of Ni alloy and Ti powder, by hot hydrostatic press (hereinafter referred to as "HIP") to produce a target material, the target material is locally low in the target material. There are cases where there is a hard part. For this reason, the target material body may be deformed during handling such as chucking or bonding when machining the target material to a predetermined shape and dimensions.

In addition, Mo-Ni-Ti alloy is not only a so-called difficult-to-cut material that has a high possibility of cracking, cracking, or falling off during machining. If there is a local high-hardness part in the target material, it may cause abrasion of chips of the cutting tool. Damage may be caused, and the surface roughness of the resulting target material may increase, or in some cases, the target material main body may be damaged.

In addition, if a localized low-hardness region exists in the eroded region of the central portion of the sputtering surface of the target material, only the low-hardness region remains or falls off, resulting in roughness of the surface of the eroded region, causing abnormalities during sputtering. It becomes easy to become the starting point of discharge.

An object of the present invention is a Mo alloy target material capable of simultaneously achieving suppression of abnormal discharge during sputtering, as well as suppressing the deformation of the target material in handling such as chucking or bonding, and abrasion or damage of chips of the cutting tool. Is to provide.

The Mo alloy target material of the present invention contains 10 to 49 atomic% of Ni and 1 to 30 atomic% of Ti, and the total amount of Ni and Ti is 50 atomic% or less, and the balance is composed of Mo and unavoidable impurities, Vickers The hardness is 340 to 450 HV, and the standard deviation of the Vickers hardness measured at 9 measuring points is 20 HV or less.

The Mo alloy target material of the present invention contains 10 to 49 atomic% of Ni and 1 to 30 atomic% of Ti, and the total amount of Ni and Ti is 50 atomic% or less, and the balance is Mo and unavoidable impurities. And NiMo alloy powder and Ti powder are mixed to obtain a mixed powder, the mixed powder is pressurized at room temperature to obtain a green body, and the green body is pressurized and sintered to obtain a sintered body. have.

The present invention can provide a Mo alloy target material with adjusted Vickers hardness. Thereby, it is possible to suppress deformation of the target material in handling such as chucking and bonding, and abrasion or breakage of chips of the cutting tool, and it is expected to simultaneously achieve suppression of abnormal discharge during sputtering. For this reason, it becomes a technique useful for the production of the above-described, for example, FPD.

1 is an optical microscope observation photograph of a sputtered surface of a target material of Example 1 of the present invention.
Fig. 2 is an optical microscope observation photograph of a sputtered surface of a target material of a comparative example.

The target material of the present invention has a Vickers hardness specified in JIS Z 2244 in the range of 340 to 450 HV, and a standard deviation of the Vickers hardness measured at 9 arbitrary measurement points is 20 HV or less. The target material of the present invention can suppress the deformation of the target material body during handling such as chucking or bonding in machining by making the Vickers hardness in a specific range and reducing the deviation (standard deviation). In addition, it is preferable that the target material of the embodiment of the present invention has a standard deviation of Vickers hardness measured at nine arbitrary measurement points of 17 HV or less.

Further, in the target material of the present invention, by adjusting the Vickers hardness to a specific range, it is possible to suppress the generation of the constituent blade edges in chips such as a phrase board or a lathe. That is, in the target material of the present invention, as the cutting process proceeds, the cutting amount of the chip accompanying the growth of the component edge is suppressed from gradually increasing, so that the dimensional difference of the target material at the start of cutting and the completion of cutting can be reduced. , It is also possible to suppress the breakage of the chip accompanying peeling of the component blade.

On the other hand, if there is a locally low hardness region composed of, for example, a Mo matrix or MoTi phase, in the central erosion region of the sputtering surface of the target material, only the low hardness region remains or falls out. In some cases, the surface of the eroded region of the target material becomes rough, and it becomes easy to become a starting point of abnormal discharge during sputtering. For this reason, the target material of the present invention has a Vickers hardness of 340 HV or more. And, for the same reason as described above, it is preferable that the target material of the embodiment of the present invention has a Vickers hardness of 345 HV or more.

By setting the Vickers hardness to 450 HV or less, the target material of the present invention can suppress the wear amount of chips such as a phrase board or a lathe. That is, in the target material of the present invention, as the cutting process proceeds, the amount of cutting of the chip caused by the wear of the chip gradually decreases, and it is possible to suppress an increase in the dimensional difference of the target material at the start of cutting and when the cutting is completed. It is also possible to suppress the breakage of.

In addition, when the Vickers hardness of the target material of the present invention is 450 HV or less, damage to the target material body can be suppressed not only by chucking to a cutting machine, but also by handling when bonding to a backing plate or a backing tube. For the same reason as described above, it is preferable that the target material of the embodiment of the present invention has a Vickers hardness of 445 HV or less.

The Vickers hardness referred to in the present invention is not only suppressing the deformation of the target material described above, abrasion or damage of the chips of the cutting tool, but also suppressing abnormal discharge during sputtering, in all directions around the center of the sputtering surface of the target material 1.5 In mm, it is measured at arbitrary nine points. At this time, the load is 9.8 N, and the pressurization time is 10 seconds.

In addition, the target material of the present invention means that the Vickers hardness measured under the above conditions is in the range of 340 to 450 HV, and the standard deviation of the Vickers hardness measured at the nine measuring points is 20 HV or less.

In addition, it is preferable that the target material of the embodiment of the present invention is formed of a Mo-Ni-Ti alloy phase from the viewpoint of having a Vickers hardness of 340 to 450 HV.

In addition, the target material of the present invention contains 10 to 49 atomic% of Ni and 1 to 30 atomic% of Ti, and the total amount of Ni and Ti is 50 atomic% or less, and the sum of Ni, Ti and Mo is 100 It has a composition containing inevitable impurities in atomic percent. The content of Ni and Ti is defined as a range that does not significantly impair adhesion, heat resistance, and moisture resistance.

When the Ni content is 10 atomic% or more, an oxidation inhibitory effect can be obtained. In addition, Ni is an element that is more likely to thermally diffuse to Cu or Al than Mo, and may increase the electrical resistance value. For this reason, the Ni content is set to 49 atomic% or less. Further, for the same reason as described above, the content of Ni is preferably 25 atomic% or less, more preferably 20 atomic% or less.

Moisture resistance can be improved by setting the content of Ti to 1 atomic% or more. Moreover, the etching property can be improved by setting the content of Ti to 30 atomic% or less. Further, for the same reason as described above, the content of Ti is preferably 20 atomic% or less, more preferably 15 atomic% or less.

In addition, Ti is also an element that is more likely to thermally diffuse to Cu or Al than Mo. For this reason, in the target material of the present invention, Ni is 10 to 49 atomic%, Ti is 1 to 30 atomic%, and the sum of Ni and Ti is 50 atomic% or less.

The target material of the present invention can be obtained by the following manufacturing method, and its general form will be described. In addition, the present invention is not limited by the form described below.

First, Mo powder and NiMo alloy powder and Ti are made so that the total amount of Ni and Ti is 50 atomic% or less, and the balance is made of Mo and inevitable impurities. The powder is mixed to obtain a mixed powder. Then, this mixed powder is pressurized at room temperature (20±15° C. specified in JIS Z 8703) using, for example, a cold hydrostatic press (hereinafter referred to as “CIP”) to obtain a molded body.

Next, this molded body is pressurized and sintered to obtain a sintered body, and the target material of the present invention can be obtained by performing machining on it. Here, in the method of manufacturing a target material according to the embodiment of the present invention, after the step of obtaining the sintered body by applying the conditions of pressure sintering to be described later, the Vickers hardness is adjusted without performing a heat treatment for removing residual stress of the target material or adjusting the Vickers hardness. You can get the target material.

In addition, in the target material of the embodiment of the present invention, from the viewpoint of effectively reducing the variation in Vickers hardness of the entire target material, in the manufacturing method thereof, before the step of obtaining the sintered body, the ``step of pulverizing the sintered body to obtain crushed powder'' Inclusion, in the step of obtaining the sintered compact, it is preferable to press-sinter the crushed powder to obtain a sintered compact. For example, it is preferable to pulverize the molded body once with, for example, a disk mill, to produce crushed powder of 1.5 mm under, and to obtain a sintered body by pressure sintering the crushed powder, and mechanically process it.

Pressurized sintering can be applied by HIP or hot press. It is preferable to carry out under conditions of 800-1,200 degreeC, 10-200 MPa, and 1-10 hours. The choice of these conditions depends on the pressure sintering apparatus. For example, HIP is easy to apply at low temperature and high pressure, and hot press is easy to apply at high temperature and low pressure. In the production method of the present invention, it is preferable to use HIP in which sintering at a low temperature is possible for pressure sintering, diffusion of Ni alloy or Ti can be suppressed, and sintering at high pressure to obtain a high-density sintered body.

By setting the sintering temperature to 800°C or higher, sintering is promoted, and a high-density sintered body can be obtained. Further, for the same reason as described above, the sintering temperature is preferably set to 900°C or higher.

On the other hand, by setting the sintering temperature to 1,200°C or less, it is possible to suppress liquid phase expression and crystal growth of the sintered body, thereby obtaining a uniform and fine metal structure. Further, for the same reason as described above, the sintering temperature is preferably set to 1,100°C or less.

When the pressing force is 10 MPa or more, sintering is promoted and a high-density sintered body can be obtained. Further, when the pressing force is 200 MPa or less, the introduction of residual stress to the target material during sintering is suppressed, the occurrence of cracks after sintering can be suppressed, and a general-purpose pressure sintering apparatus can be used.

By setting the sintering time to 1 hour or more, sintering can be sufficiently advanced, and a high-density sintered body can be obtained. Further, by setting the sintering time to 10 hours or less, a decrease in manufacturing efficiency can be suppressed.

Example

Mo powder with a 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on volume is 7 µm, NiMo alloy powder with D50 of 35 µm, Ti powder with D50 of 30 µm, and 30 Ni It contained atomic% and 20 atomic% Ti, and the balance was mixed so as to consist of Mo and inevitable impurities to obtain a mixed powder.

Then, this mixed powder was filled into a rubber mold, and CIP treatment was performed under conditions of a molding pressure of 2.7 ton/cm 2 (≒2.65 MPa) to obtain a molded article.

Next, the molded body obtained above was installed inside the furnace body of the HIP apparatus, and pressure sintered under conditions of 1,000° C., 120 MPa, and 5 hours, and the Mo alloy sintered body as the target material of the present invention example 1 was obtained. Got it.

Mo powder with a 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on volume is 7 µm, NiMo alloy powder with D50 of 35 µm, Ti powder with D50 of 30 µm, and 20 Ni It contained atomic% and 20 atomic% Ti, and the balance was mixed so as to consist of Mo and inevitable impurities to obtain a mixed powder.

Then, this mixed powder was filled into a rubber mold, and CIP treatment was performed under conditions of a molding pressure of 2.7 ton/cm 2 (≒2.65 MPa) to obtain a molded article. This molded body was pulverized by a disk mill to obtain crushed powder of 1.5 mm under.

Next, the crushed powder obtained above was installed inside the furnace body of the HIP apparatus, and pressure sintered under conditions of 1,000° C., 120 MPa, and 5 hours to obtain a Mo alloy sintered body serving as a target material of the present invention example 2 was obtained.

Mo powder with a 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on volume is 7 µm, NiMo alloy powder with D50 of 35 µm, Ti powder with D50 of 30 µm, and Ni with 49 It contained atomic% and 1 atomic% of Ti, and mixed so that the remainder consisted of Mo and inevitable impurities to obtain a mixed powder.

Then, this mixed powder was filled into a rubber mold, and CIP treatment was performed under conditions of a molding pressure of 2.7 ton/cm 2 (≒2.65 MPa) to obtain a molded article. This molded body was pulverized by a disk mill to obtain crushed powder of 1.5 mm under.

Next, the pulverized powder obtained above was installed inside the furnace body of the HIP apparatus, and pressure sintered under conditions of 1,000°C, 120 MPa, and 5 hours to obtain a Mo alloy sintered body serving as a target material of Example 3 of the present invention.

Mo powder with a 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on volume is 7 µm, NiMo alloy powder with D50 of 35 µm, Ti powder with D50 of 30 µm, and Ni of 10 It contains atomic% and 30 atomic% of Ti, and the balance is mixed so as to consist of Mo and unavoidable impurities to obtain a mixed powder.

Then, this mixed powder was filled into a rubber mold, and CIP treatment was performed under conditions of a molding pressure of 2.7 ton/cm 2 (≒2.65 MPa) to obtain a molded article.

Next, the molded body obtained above was installed inside the furnace body of the HIP apparatus, and pressure sintered under conditions of 1,000°C, 120 MPa, and 5 hours to obtain a Mo alloy sintered body serving as a target material of the present invention example 4 was obtained.

Mo powder with a D50 of 7 µm, NiMo alloy powder with a D50 of 35 µm, and a Ti powder with a D50 of 30 µm, containing 30 atomic% Ni and 20 atomic% Ti, and the balance as Mo and inevitable impurities The mixture was mixed to obtain a mixed powder.

Then, this mixed powder was filled in a pressurized container made of mild steel, installed inside the furnace body of a HIP apparatus, and sintered under pressure under conditions of 1,000°C, 120 MPa, and 5 hours, and the Mo alloy sintered body as the target material of the comparative example Got it.

A test piece was collected by machining at an arbitrary position on the surface to be the sputtered surface of each of the sintered bodies obtained above. In addition, Vickers hardness was measured at measurement points corresponding to 9 points shown in Figs. 1 and 2 using MVK-E manufactured by Akashi Co., Ltd. according to JIS Z 2244. The results are shown in Table 1.

Here, it was confirmed that all of the Mo alloy sintered bodies serving as examples of the present invention had no chip abrasion or breakage during machining to obtain the shape of the target material. Moreover, since there was no dropping of the Mo alloy sintered body in the machining, suppression of abnormal discharge during sputtering can also be expected. In addition, there was no case where the Mo alloy sintered body was deformed or damaged during handling such as chucking on a cutting machine.

On the other hand, in the Mo alloy sintered body as a comparative example, chip abrasion or breakage occurred during machining to form a target material. In addition, dropping of the Mo alloy sintered body was confirmed during the machining.

1 and 2 show the results of observing the metal structure of the surface of each target material as a sputtering surface with an optical microscope.

The target material serving as a comparative example was a metal structure in which a coarse Ni alloy phase represented by a light gray portion was scattered on the Mo phase serving as the matrix shown in FIG. 2, and it was confirmed that the variation (standard deviation) in Vickers hardness exceeded 20 HV.

On the other hand, the target material used as Inventive Example 1 has a finely dispersed Ni alloy phase represented by the light gray portion of Fig. 1, and thus there is no coarse Ni alloy phase shown in the comparative example, and the variation (standard deviation) of Vickers hardness is less than 20 HV. It was confirmed that it was adjusted. Thereby, the target material of the present invention can not only suppress the deformation of the target material during handling and the wear or damage of the chips of the cutting tool, but also suppress the generation of abnormal discharge starting points during sputtering.

Claims (2)

It contains 10 to 49 atomic% of Ni and 1 to 30 atomic% of Ti, and the total amount of Ni and Ti is 50 atomic% or less, the balance is made of Mo and inevitable impurities, and the Vickers hardness is 340 to 450 HV. , Mo alloy target material having a standard deviation of Vickers hardness measured at 9 measuring points of 20 HV or less. Mo powder and NiMo alloy powder and Ti powder so that Ni is 10 to 49 atomic%, Ti is 1 to 30 atomic%, and the total amount of Ni and Ti is 50 atomic% or less, and the balance becomes Mo and unavoidable impurities. A method for producing a Mo alloy target material comprising a step of mixing to obtain a mixed powder, a step of pressing the mixed powder at room temperature to obtain a molded body, and a step of pressing the molded body to obtain a sintered body.

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