阅读说明：本技术 Mo合金靶材及其制造方法 (Mo alloy target material and manufacturing method thereof ) 是由 青木大辅 福冈淳 熊谷卓哉 于 2020-03-20 设计创作，主要内容包括：本发明涉及Mo合金靶材及其制造方法。本申请提供一种Mo合金靶材,其能够同时达成抑制夹持、接合等操作中的靶材变形、切削工具的刀头磨耗、破损,并且抑制溅射时的异常放电。一种Mo合金靶材,其含有10～49原子％的Ni、1～30原子％的Ti并且Ni和Ti的总量为50原子％以下,余量为Mo以及不可避免的杂质；所述Mo合金靶材的维氏硬度为340～450HV,以9个测定点进行测定而得到的维氏硬度的标准偏差为20HV以下。(The invention relates to a Mo alloy target material and a manufacturing method thereof. Provided is a Mo alloy target material which can simultaneously suppress target material deformation, wear of a cutting tip of a cutting tool, and damage in operations such as clamping and bonding, and can suppress abnormal discharge during sputtering. A Mo alloy target material containing 10 to 49 at% of Ni and 1 to 30 at% of Ti, wherein the total amount of Ni and Ti is 50 at% or less, and the balance being Mo and unavoidable impurities; the Vickers hardness of the Mo alloy target is 340-450 HV, and the standard deviation of the Vickers hardness measured by 9 measuring points is less than 20 HV.)

1. A Mo alloy target material containing 10 to 49 at% of Ni and 1 to 30 at% of Ti, wherein the total amount of Ni and Ti is 50 at% or less, and the balance being Mo and unavoidable impurities; the Vickers hardness of the Mo alloy target is 340-450 HV, and the standard deviation of the Vickers hardness measured by 9 measuring points is less than 20 HV.

2. A manufacturing method of a Mo alloy target material comprises the following steps: a step of mixing Mo powder, NiMo alloy powder and Ti powder so as to contain 10 to 49 at% of Ni and 1 to 30 at% of Ti, the total amount of Ni and Ti being 50 at% or less, and the balance being Mo and unavoidable impurities, thereby obtaining a mixed powder; a step of pressurizing the mixed powder at room temperature to obtain a molded body; and a step of subjecting the compact to pressure sintering to obtain a sintered body.

Technical Field

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

Background

In Flat Display devices such as electrophoretic displays (Flat Panel displays, hereinafter referred to as FPDs), various semiconductor devices, thin film sensors, and thin film electronic components such as magnetic heads, wiring films having low resistance values (hereinafter referred to as low resistance) are required. For example, with a large screen, high definition, and fast response, wiring films of FPDs are required to have a low resistance. In recent years, new products such as a touch panel that has increased operability in an FPD, and a flexible FPD that uses a resin substrate have been developed.

A wiring Thin film of a Thin film transistor (hereinafter, referred to as a TFT) used as a driving element of an FPD needs to have a low resistance, and the following studies have been made on a wiring material: the conventional Al is changed to Cu with lower resistance.

At present, when an amorphous Si semiconductor film is used in a TFT and Cu as a wiring film is in direct contact with Si, thermal diffusion occurs due to a heating step in TFT manufacturing, and the characteristics of the TFT are degraded. Therefore, a laminated wiring film using Mo or Mo alloy having excellent heat resistance as a barrier film is used as a cover film between Cu and Si.

Further, application studies of a transparent semiconductor film using an oxide which can achieve faster response than a conventional amorphous Si semiconductor film have been conducted, and a multilayer wiring film having a structure in which a wiring film of an oxide semiconductor is further laminated with a wiring film formed of Cu, a base film formed of Mo or Mo alloy, or a cap film has been studied. Therefore, a thin film made of a Mo alloy used for forming these multilayer wiring films is in high demand.

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

On the other hand, as a method for forming the Mo alloy thin film, a sputtering method using a sputtering target (hereinafter, simply referred to as "target") is most suitable. The sputtering method is one of physical vapor deposition methods, and is a method capable of stably forming a Mo alloy thin film over a large area as compared with other vacuum vapor deposition and ion plating methods, and is an effective method capable of obtaining an excellent Mo alloy thin film with little compositional variation even in an alloy containing a large amount of the above-described additive elements.

As a method for obtaining the above-described target material made of a Mo — Ni — Ti alloy, for example, patent document 1 proposes a method of applying a machining process to a sintered body obtained by mixing a Mo powder and one or more Ni alloy powders, or a sintered body obtained by pressure sintering a mixed powder obtained by mixing a Mo powder, a Ni alloy powder, and a Ti powder.

Disclosure of Invention

Problems to be solved by the invention

As disclosed in patent document 1, when a target material is produced by pressure sintering a mixed powder obtained by mixing a Mo powder, a Ni alloy, and a Ti powder by hot isostatic pressing (hereinafter referred to as "HIP"), the target material may have a portion having a low local hardness. Therefore, the target body may be deformed in operations such as clamping and bonding when machining the target into a predetermined shape and size.

Further, the Mo — Ni — Ti alloy is a so-called difficult-to-cut material having a high possibility of causing cracks, defects, and detachment at the time of machining, and when a portion having a high local hardness is present in the target material, the cutting edge of the cutting tool is worn or damaged, and the surface roughness of the obtained target material is increased, or in some cases, the target material body is damaged.

Further, when a portion having a low local hardness is present in the erosion region in the central portion of the sputtering surface of the target, only the portion having a low hardness remains, or only the portion having a low hardness comes off, and the surface roughness of the erosion region becomes rough, which is likely to become a starting point of abnormal discharge during sputtering.

The present invention aims to provide a Mo alloy target material that can simultaneously suppress deformation of the target material, wear of a cutting tip of a cutting tool, and damage during operations such as clamping and bonding, and suppress abnormal discharge during sputtering.

Means for solving the problems

The Mo alloy target material contains 10-49 atom% of Ni and 1-30 atom% of Ti, wherein the total amount of Ni and Ti is less than 50 atom%, and the balance is Mo and inevitable impurities; the Vickers hardness of the Mo alloy target is 340-450 HV, and the standard deviation of the Vickers hardness measured by 9 measuring points is less than 20 HV.

The Mo alloy target of the present invention can be obtained by a production method including the steps of: a step of mixing Mo powder, NiMo alloy powder and Ti powder so as to contain 10 to 49 at% of Ni and 1 to 30 at% of Ti, the total amount of Ni and Ti being 50 at% or less, and the balance being Mo and unavoidable impurities, thereby obtaining a mixed powder; a step of pressurizing the mixed powder at room temperature to obtain a molded body; and a step of subjecting the molded body to pressure sintering to obtain a sintered body.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention can provide the Mo alloy target material with the Vickers hardness adjusted. This can be expected to simultaneously suppress deformation of the target material, wear of the cutting tip of the cutting tool, and damage during operations such as clamping and bonding, and suppress abnormal discharge during sputtering. Therefore, the technique is useful for manufacturing the FPD and the like.

Drawings

FIG. 1 is an optical microscopic photograph of a sputtering surface of a target material in example 1 of the present invention.

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

Detailed Description

The target material of the present invention has a Vickers hardness of 340 to 450HV as defined in JIS Z2244, and has a standard deviation of Vickers hardness of 20HV or less as measured at arbitrary 9 measurement points. In the target of the present invention, the vickers hardness is set to a specific range, and the variation (standard deviation) thereof is reduced, whereby the deformation of the target body during operations such as clamping and bonding in machining can be suppressed. The target according to the embodiment of the present invention preferably has a vickers hardness standard deviation of 17HV or less, which is measured at any of 9 measurement points.

In addition, the target material of the present invention can suppress the generation of build-up (build-up edge) on a tool bit of, for example, a milling machine, a lathe, or the like by adjusting the vickers hardness to a specific range. That is, the target material of the present invention can suppress the gradual increase in the depth of the cutting tip accompanying the growth of the built-up edge as the cutting process is performed, reduce the difference in the size between the target material at the start of cutting and the target material at the completion of cutting, and suppress the breakage of the cutting tip accompanying the separation of the built-up edge.

On the other hand, if a local low-hardness portion composed of, for example, a Mo matrix phase or MoTi phase is present in the erosion region in the central portion of the sputtering surface of the target, only the low-hardness portion may remain or fall off, the surface of the erosion region of the target may become rough, and this may easily become a starting point of abnormal discharge during sputtering. Therefore, the vickers hardness of the target material of the present invention is 340HV or more. For the same reason as described above, the vickers hardness of the target according to the embodiment of the present invention is preferably 345HV or more.

By setting the vickers hardness of the target material of the present invention to 450HV or less, the amount of wear of the tool bit of, for example, a milling machine, a lathe, or the like can be suppressed. That is, the target material of the present invention can suppress the size difference between the target material at the start of cutting and at the completion of cutting from becoming large as the depth of the cutting tip gradually decreases with the wear of the cutting tip as the cutting process progresses; and also can suppress the breakage of the tip.

Further, the vickers hardness of the target material of the present invention is set to 450HV or less, so that damage to the target material body can be suppressed in operations such as clamping by a cutting machine and joining to a backing plate or a backing tube. For the same reason as described above, the vickers hardness of the target according to the embodiment of the present invention is preferably 445HV or less.

The vickers hardness in the present invention was measured at arbitrary 9 points in the vicinity of 1.5mm in the center of the sputtering surface of the target material, from the viewpoints of suppressing the deformation of the target material, the wear and damage of the cutting tip of the cutting tool, and the suppression of abnormal discharge during sputtering. At this time, the load was set to 9.8N, and the pressing time was set to 10 seconds.

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

The target material according to the embodiment of the present invention is preferably made of a Mo-Ni-Ti alloy phase from the viewpoint of having a Vickers hardness of 340 to 450 HV.

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

The content of Ni is 10 atomic% or more, and an oxidation suppression effect can be obtained. Further, Ni is an element that is more easily thermally diffused into Cu and Al than Mo, and may increase the resistance value. Therefore, the Ni content is 49 atomic% or less. For the same reason as described above, the content of Ni is preferably 25 at% or less, and more preferably 20 at% or less.

The moisture resistance can be improved by setting the content of Ti to 1 atomic% or more. Further, the content of Ti is 30 atomic% or less, so that the etching property can be improved. For the same reason as described above, the Ti content is preferably 20 at% or less, and more preferably 15 at% or less.

Further, Ti is also an element that is more easily thermally diffused into Cu and Al than Mo. Therefore, in the target material of the present invention, Ni is 10 to 49 atomic%, Ti is 1 to 30 atomic%, and the total of Ni and Ti is 50 atomic% or less.

The target material of the present invention can be obtained by the following production method, and a general mode thereof will be described. The present invention is not limited to the following embodiments.

First, a Mo powder, a NiMo alloy powder and a Ti powder are mixed so as to contain 10 to 49 at% of Ni and 1 to 30 at% of Ti, the total amount of Ni and Ti being 50 at% or less, and the balance being Mo and unavoidable impurities, thereby obtaining a mixed powder. Then, the mixed powder is pressed at normal temperature (20 ± 15 ℃ as defined in JIS Z8703), for example, by cold isostatic pressing (hereinafter, referred to as CIP) to prepare a compact.

Next, the compact is pressure-sintered to obtain a sintered body, and machining is performed on the sintered body, thereby obtaining the target material of the present invention. Here, in the method for manufacturing a target according to the embodiment of the present invention, after the step of obtaining the above-described sintered body by applying the conditions of pressure sintering described later, the target with the adjusted vickers hardness can be obtained without performing the heat treatment for removing the residual stress of the target and adjusting the vickers hardness.

In the target according to the embodiment of the present invention, it is preferable that the method for producing the target includes a step of obtaining the above-mentioned sintered body by including a "step of obtaining a pulverized powder by pulverizing the above-mentioned compact" prior to the step of obtaining the above-mentioned sintered body, and the sintered body is obtained by pressure sintering the pulverized powder, from the viewpoint of effectively reducing variation in vickers hardness of the entire target. Preferably, for example, the above-mentioned compact is first pulverized by a disk mill or the like to prepare a pulverized powder having a particle size of 1.5mm or less, the pulverized powder is pressure-sintered to obtain a sintered body, and the sintered body is subjected to machining.

The pressure sintering can be performed by HIP and hot pressing, preferably at 800-1200 ℃ under 10-200 MPa for 1-10 hours. The selection of these conditions depends on the apparatus in which the pressure sintering is carried out. For example, in the case of HIP, conditions of low temperature and high pressure are easily applied, and in the case of hot pressing, conditions of high temperature and low pressure are easily applied. In the production method of the present invention, HIP that can be sintered at a low temperature to suppress diffusion of Ni alloy and Ti and can be sintered at a high pressure to obtain a high-density sintered body is preferably used in the pressure sintering.

The sintering temperature is set to 800 ℃ or higher, whereby sintering can be promoted and a high-density sintered body can be obtained. For the same reason as described above, the sintering temperature is preferably 900 ℃ or higher.

On the other hand, by setting the sintering temperature to 1200 ℃ or lower, occurrence of a liquid phase and crystal growth of the sintered body can be suppressed, and a uniform and fine metallographic structure can be obtained. For the same reason as described above, the sintering temperature is preferably 1100 ℃.

The pressurizing force is set to 10MPa or more, whereby sintering can be promoted and a high-density sintered body can be obtained. Further, by setting the pressing force to 200MPa or less, introduction of residual stress into the target during sintering can be suppressed, 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 promoted, and a sintered body with high density can be obtained. Further, the sintering time is set to 10 hours or less, so that the reduction of the production efficiency can be suppressed.