TWI715466B - Molybdenum alloy target material and manufacturing method thereof - Google Patents

Abstract

The present invention provides a molybdenum alloy target material, which not only suppresses the deformation of the target material or the wear or breakage of the blade of a cutting tool during processing such as clamping or joining, but also suppresses abnormal discharge during sputtering. A molybdenum alloy target material containing Ni at 10 at% to 49 at %, Ti at 1 at% to 30 at %, and the total amount of Ni and Ti is 50 at% or less, and the remainder contains Mo and unavoidable impurities, The Vickers hardness is 340 HV to 450 HV, and the standard deviation of the Vickers hardness measured at 9 measuring points is 20 HV or less.

Description

Molybdenum alloy target material and manufacturing method thereof

The present invention relates to a molybdenum (Mo) alloy target used for forming electrodes or wiring films for electronic parts, for example, and a manufacturing method thereof.

In flat display devices such as electrophoretic displays (flat panel displays, flat panel displays: hereinafter referred to as FPD), various semiconductor components, thin-film sensors, magnetic heads, and other thin-film electronic components, low resistance values (hereinafter, also referred to as " "Low resistance") wiring film. For example, in FPD, along with large screen, high definition, and high-speed response, low resistance of its wiring film is required. In addition, in recent years, new products such as touch panels that impart operability to FPDs or 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 be low in resistance, and studies are underway to change the wiring material from Al to Cu, which has a lower resistance.

At present, the TFT uses an amorphous Si semiconductor film. If Cu and Si as a wiring film are in direct contact, thermal diffusion occurs during the heating step in the TFT manufacturing process, thereby deteriorating the characteristics of the TFT. Therefore, a build-up wiring film in which Mo or Mo alloy having excellent heat resistance is used as a barrier film between Cu and Si is used as a cover film.

In addition, from the conventional amorphous Si semiconductor films, the application research of transparent semiconductor films using oxides that can further achieve high-speed response has been conducted. These oxide semiconductor wiring films have also been examined for a build-up wiring film having a structure in which a wiring film containing Cu and a base film or cover film containing Mo or Mo alloy are laminated. Therefore, the demand for thin films containing Mo alloys for forming these multilayer wiring films has increased.

Furthermore, as a Mo alloy thin film having high moisture resistance and suitable for mobile devices or in-vehicle devices, Mo-Ni-Ti alloys have been proposed.

On the other hand, as a method of forming the Mo alloy thin film, a sputtering method using a sputtering target (hereinafter, also simply referred to as "target") is the most preferable. The sputtering method is one of the physical vapor deposition methods. Compared with other vacuum vapor deposition or ion plating, it is a method that can form a large area of Mo alloy thin film stably, and it can be obtained even if it is an alloy with a large amount of added elements as described above. An effective method for excellent Mo alloy thin films with little composition variation.

Moreover, as a method of obtaining a target material containing the Mo-Ni-Ti alloy, for example, Patent Document 1 proposes a method of machining a sintered body that is mixed with Mo powder and one or more kinds of Ni alloy powder or a mixed powder of Mo powder, Ni alloy powder and Ti powder are pressure-sintered.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-177696

If Hot Isostatic Pressing (hereinafter referred to as "HIP") is used to compare the mixture of Mo powder, Ni alloy powder and Ti powder disclosed in Patent Document 1 The mixed powder is subjected to pressure sintering to produce a target, and there may be local low-hardness sites in the target. Therefore, in processes such as clamping or joining when machining the target material into a predetermined shape and size, the target body may be deformed.

In addition, Mo-Ni-Ti alloy is a so-called difficult-to-cut material that has a high possibility of cracking, chipping, and falling off during machining. Moreover, if there are local high hardness parts in the target material, it will cause the cutting tool blade The abrasion or damage of the target material may increase the surface roughness of the target material obtained, or the target body may be damaged depending on the situation.

In addition, if there is a local low-hardness site in the erosion area at the center of the sputtering surface of the target, only the low-hardness site remains or falls off. This causes the surface roughness of the erosion area to become rough and easily becomes sputtering. The starting point of the abnormal discharge at the time.

The object of the present invention is to provide a Mo alloy target material that can suppress abnormal discharge during sputtering in addition to suppressing deformation of the target material during chucking or joining, or wear or breakage of cutting tool blades.

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

The Mo alloy target of the present invention can be obtained by the following manufacturing method, the manufacturing method includes: containing 10 atomic% to 49 atomic% of Ni, 1 atomic% to 30 atomic% of Ti, and the total amount of Ni and Ti Less than 50 atomic%, the remainder includes A step of mixing Mo powder, NiMo alloy powder and Ti powder to obtain a mixed powder in a manner containing Mo and unavoidable impurities; a step of pressing the mixed powder at room temperature to obtain a molded body; and The step of pressure sintering the body to obtain a sintered body.

The invention can provide a Mo alloy target material with adjusted Vickers hardness. This is expected to be able to suppress the deformation of the target material during processing such as chucking or joining, or the wear or breakage of the blade of the cutting tool, while also suppressing abnormal discharge during sputtering. Therefore, it becomes such a useful technique for manufacturing FPDs.

Fig. 1 is an optical microscope observation photograph of the sputtering surface of a target of Example 1 of the present invention.

Fig. 2 is an optical microscope observation photograph of the sputtering surface of a target of a comparative example.

Regarding the target material of the present invention, the Vickers hardness specified in Japanese Industrial Standards (JIS) Z 2244 is within the range of 340HV to 450HV, and the standard deviation of the Vickers hardness measured at any 9 measurement points Below 20HV. In the target of the present invention, by setting the Vickers hardness to a specific range and reducing the deviation (standard deviation), it is possible to suppress the deformation of the target body during processing such as clamping or joining in machining. Furthermore, it is preferable that the target material of the embodiment of the present invention has a standard deviation of the Vickers hardness measured at any 9 measurement points of 17 HV or less.

In addition, in the target material of the present invention, by adjusting the Vickers hardness to a specific range It can suppress the formation of cutting edge on the blades such as milling machines or lathes. That is, the target material of the present invention can prevent the cutting amount of the blade from gradually increasing as the cutting edge grows as the cutting process progresses, and can reduce the size difference between the target material at the beginning of cutting and the end of cutting, in addition to this In addition, the breakage of the blade caused by the peeling of the cutting edge can be suppressed.

On the other hand, if there is a local low-hardness site composed of Mo matrix phase or MoTi in the erosion area at the center of the sputtering surface of the target, only the low-hardness site may remain or fall off. The surface of the eroded area becomes rough and easily becomes the starting point of abnormal discharge during sputtering. Therefore, the Vickers hardness of the target material of the present invention is 340 HV or more. Furthermore, for the same reason as described above, the target material of the embodiment of the present invention preferably has a Vickers hardness of 345 HV or more.

In the target material of the present invention, the Vickers hardness is 450 HV or less, so that, for example, the wear amount of the blade of a milling machine or a lathe can be suppressed. That is, the target material of the present invention can suppress that the cutting amount of the blade gradually decreases with the wear of the blade as the cutting process progresses, and the size difference between the target material at the start of cutting and the end of the cutting increases, among other things It can restrain the damage of the blade.

In addition, by setting the Vickers hardness of the target material of the present invention to 450 HV or less, in addition to clamping the cutting machine, damage to the target body can be suppressed during processing when joining with a backing plate or a backing tube. Furthermore, for the same reason as described above, the target material of the embodiment of the present invention preferably has a Vickers hardness of 445 HV or less.

Regarding the Vickers hardness in the present invention, in addition to suppressing the deformation of the target material or the wear or breakage of the blade of the cutting tool, the abnormal discharge during sputtering is suppressed From the viewpoint of, the measurement is performed at arbitrary 9 points in a 1.5 mm square near the center of the sputtering surface of the target. At this time, the load was 9.8N, and the pressure time was 10 seconds.

Furthermore, the target material of the present invention means that the Vickers hardness measured under the above conditions is in the range of 340 HV to 450 HV, and the standard deviation of the Vickers hardness measured at the 9 measurement points is 20 HV or less.

In addition, from the viewpoint of setting the Vickers hardness to 340 HV to 450 HV, the target material of the embodiment of the present invention is preferably composed of a Mo-Ni-Ti alloy phase.

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

By setting the Ni content to 10 atomic% or more, an oxidation inhibitory effect can be obtained. In addition, compared with Mo, Ni is an element that is easily thermally diffused into Cu or Al, and may increase the resistance value. Therefore, the content of Ni is set to 49 atomic% or less. In addition, for the same reason as described above, the content of Ni is preferably 25 at% or less, more preferably 20 at% or less.

By making the content of Ti 1 atomic% or more, the moisture resistance can be improved. In addition, by making the content of Ti 30 atomic% or less, etching properties can be improved. In addition, for the same reason as described above, the content of Ti is preferably 20 atomic% or less, and more preferably 15 atomic% or less.

In addition, Ti is also an element that is easier to thermally diffuse to Cu or Al than Mo. Therefore, in the target material of the present invention, Ni is 10 atomic% to 49 atomic %, Ti is 1 atomic% to 30 atomic %, and the total of Ni and Ti is 50 atomic% or less.

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

First, it is mixed in such a way that it contains 10 atomic% to 49 atomic% of Ni, 1 atomic% to 30 atomic% of Ti, and the total amount of Ni and Ti is 50 atomic% or less, and the remainder contains Mo and unavoidable impurities Mo powder, NiMo alloy powder and Ti powder are mixed powders. Furthermore, the mixed powder is pressurized at room temperature (20±15°C specified in JIS Z 8703), for example, using Cold Isostaitc Pressing (hereinafter referred to as "CIP") to form a molded body .

Next, the compact is sintered under pressure to obtain a sintered body, which is subjected to mechanical processing to obtain the target of the present invention. Here, the manufacturing method of the target material of the embodiment of the present invention applies the pressure sintering conditions described later, and does not perform the step of removing the residual stress of the target material or adjusting the Vickers hardness after the step of obtaining the sintered body. The target material with adjusted Vickers hardness can be obtained.

Furthermore, from the viewpoint of effectively reducing the deviation of the Vickers hardness of the entire target material, the target material of the embodiment of the present invention preferably includes the step of obtaining the sintered body in the manufacturing method. The step of crushing the compact to obtain crushed powder". In the step of obtaining the sintered body, the crushed powder is pressure-sintered to obtain a sintered body. For example, it is preferable to crush the formed body at one time, for example, using a disc mill, to produce crushed powder of 1.5 mm or less, press and sinter the crushed powder to obtain a sintered body, and perform mechanical processing on it. .

Pressure sintering can be performed using HIP or hot pressing, preferably at 800°C to 1200°C, 10MPa to 200MPa, and 1 hour to 10 hours. The selection of these conditions depends on the pressure sintering device. For example, HIP is easy to apply low temperature and high pressure conditions, and hot pressing is easy to apply high temperature and low pressure conditions. In the manufacturing method of the present invention, pressure sintering preferably uses HIP, which can be sintered at a low temperature, can suppress the diffusion of Ni alloy or Ti, and can be sintered under high pressure to obtain a high-density sintered body.

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

On the other hand, by setting the sintering temperature to 1200°C or lower, the appearance of the liquid phase or the crystal growth of the sintered body can be suppressed, and a uniform and fine metal structure can be obtained. In addition, for the same reason as described above, the sintering temperature is preferably 1100°C or lower.

By setting the pressure to 10 MPa or more, sintering can be promoted and a high-density sintered body can be obtained. In addition, by setting the pressure to 200 MPa or less, the introduction of residual stress to the target during sintering can be suppressed, and the occurrence of cracks after sintering can be suppressed. In addition, a general-purpose pressure sintering device can be used.

By setting the sintering time to 1 hour or more, sintering can be sufficiently performed, and a high-density sintered body can be obtained. In addition, by setting the sintering time to 10 hours or less, it is possible to suppress a decrease in manufacturing efficiency.

[Example]

The cumulative particle size distribution based on volume is mixed in a way that contains 30 atomic% of Ni, 20 atomic% of Ti, and the remainder contains Mo and unavoidable impurities The 50% particle size (hereinafter referred to as "D50") is Mo powder of 7 μm, NiMo alloy powder of D50 of 35 μm, and Ti powder of D50 of 30 μm to obtain mixed powders.

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

Next, the obtained molded body was set in the furnace of the HIP device, and pressure sintering was performed under the conditions of 1000° C., 120 MPa, and 5 hours to obtain a Mo alloy sintered body as a target of Example 1 of the present invention.

The 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on the volume of mixing is 7μm Mo in a way that it contains 20 at% Ni, 20 at% Ti and the remainder contains Mo and unavoidable impurities. Powder, NiMo alloy powder with D50 of 35 μm and Ti powder with D50 of 30 μm to obtain mixed powder.

Then, the mixed powder was filled in a rubber mold, and CIP treatment was performed under a molding pressure of 2.7 ton/cm ² (≒2.65 MPa) to obtain a molded body. The formed body was crushed by a disc mill to obtain crushed powder of 1.5 mm or less.

Next, the obtained crushed powder was set in the furnace body of the HIP device, and pressure sintering was performed under the conditions of 1000° C., 120 MPa, and 5 hours to obtain a Mo alloy sintered body as a target of Example 2 of the present invention.

The 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on the volume of mixing is 7μm Mo with 49 atomic% Ni, 1 atomic% Ti and the remainder contains Mo and unavoidable impurities Powder, NiMo alloy powder with D50 of 35 μm and Ti powder with D50 of 30 μm to obtain mixed powder.

Then, the mixed powder was filled in a rubber mold, and CIP treatment was performed under a molding pressure of 2.7 ton/cm ² (≒2.65 MPa) to obtain a molded body. The formed body was crushed by a disc mill to obtain crushed powder of 1.5 mm or less.

Next, the obtained crushed powder was set in the furnace of the HIP device, and pressure sintering was performed under the conditions of 1000° C., 120 MPa, and 5 hours to obtain a Mo alloy sintered body as a target of Example 3 of the present invention.

The 50% particle size (hereinafter referred to as "D50") of the cumulative particle size distribution based on the mixing volume is 7μm Mo in a manner that contains 10 atomic% Ni, 30 atomic% Ti, and the remainder contains Mo and unavoidable impurities Powder, NiMo alloy powder with D50 of 35 μm and Ti powder with D50 of 30 μm to obtain mixed powder.

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

Next, the obtained molded body was set in the furnace of the HIP device, and pressure sintering was performed under the conditions of 1000° C., 120 MPa, and 5 hours to obtain a Mo alloy sintered body as a target of Example 4 of the present invention.

It is obtained by mixing Mo powder with a D50 of 7μm, NiMo alloy powder with a D50 of 35μm and Ti powder with a D50 of 30μm in a manner that contains 30 at% Ni, 20 at% Ti, and the remainder contains Mo and unavoidable impurities. Mix the powder.

Then, the mixed powder was filled in a pressure vessel made of mild steel, set in the furnace body of the HIP device, and pressure sintered under the conditions of 1000° C., 120 MPa, and 5 hours to obtain a target as a comparative example Mo alloy sintered body.

Arbitrary positions of the sputtering surface of each sintered body obtained from the above Take a test piece by machining. In addition, the Vickers hardness was measured at a measurement point corresponding to the 9 points shown in FIGS. 1 and 2 using MVK-E manufactured by Akashi Manufacturing Co., Ltd. based on JIS Z 2244. The results are shown in Table 1.

Here, it was confirmed that the Mo alloy sintered body as an example of the present invention has no wear or breakage of the blade when it is used for machining to form the shape of a target material. In addition, the Mo alloy sintered body does not fall off during the machining process, so it can be expected to suppress abnormal discharge during sputtering. In addition, the Mo alloy sintered body was not deformed or damaged during processing such as clamping of the cutting machine.

On the other hand, when the Mo alloy sintered body as a comparative example was used for machining to form the shape of the target, the blade was worn or broken. In addition, in the machining process, it was confirmed that the Mo alloy sintered body fell off.

The results of observing the metal structure of the sputtering surface of each target with an optical microscope are shown in FIGS. 1 and 2.

The target as a comparative example is dispersed in the Mo phase that becomes the matrix shown in Figure 2 There is a metal structure of a coarse Ni alloy phase represented by a light gray part, and it was confirmed that the deviation (standard deviation) of the Vickers hardness exceeds 20 HV.

On the other hand, in the target material of Example 1 of the present invention, it can be confirmed that the Ni alloy phase shown in the light gray part of FIG. 1 is finely dispersed, and there is no coarse Ni alloy phase observed in the comparative example, and the deviation of Vickers hardness (Standard deviation) is adjusted to 20HV or less. Thereby, the target of the present invention can be expected to suppress the deformation of the target during processing or the wear or breakage of the blade of the cutting tool, and it can also be expected to suppress the generation of the starting point of abnormal discharge during sputtering.

Claims (2)

A molybdenum alloy target material containing Ni at 10 at% to 49 at %, Ti at 1 at% to 30 at %, and the total amount of Ni and Ti is 50 at% or less, and the remainder contains Mo and unavoidable impurities, The Vickers hardness is 340 HV to 450 HV, and the standard deviation of the Vickers hardness measured at 9 measuring points is 20 HV or less. A method for manufacturing a molybdenum alloy target material, including: The Mo powder is mixed so that it contains 10 atomic% to 49 atomic% of Ni, 1 atomic% to 30 atomic% of Ti, and the total amount of Ni and Ti is 50 atomic% or less, and the remainder contains Mo and inevitable impurities , NiMo alloy powder and Ti powder to obtain mixed powder steps; The step of pressing the mixed powder at room temperature to obtain a molded body; and The step of pressure-sintering the compact to obtain a sintered body.

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