TW201516169A - Method for regenerating spent sputtering target and sputtering target regenerated thereby - Google Patents

Abstract

The present disclosure relates to a method for regenerating a spent sputtering target and a sputtering target regenerated thereby. The method includes S(1) removing an impurity from a surface of the spent sputtering target; S(2) inserting the spent sputtering target from which the impurity is removed into a mold; S(3) filling and planarizing a raw material powder in the spent sputtering target which is inserted into the mold to form a laminate; S(4) pressurizing the laminate to form a molded body; and S(5) sintering the molded body.

Description

Recycling method for discarded sputter target and regenerated sputter target

The present invention relates to a method of regenerating a waste sputter target and a sputter target regenerated by the method.

The sputtering target is applied to fabricate a semiconductor memory device (RAM, MRAM, or FeRAM), a magnetic head (MR or TMR), or a capacitor to form an electrode layer or a seed layer on a wafer, glass, or target (substrate).

Generally, according to a sputtering process, when ions are accelerated by collision of a plasma with a target, atoms are excited from the surface of the target and then deposited on the surface of the substrate to form a thin film layer. However, in this sputtering process, only 50% or less of the sputtering target is consumed, and most of the remaining sputtering targets remain and are not used. As shown in Figures 14 and 15, typically only about 30 to 40% of the sputter target will be used, although it may vary depending on the processing conditions or the material of the target. Therefore, in the related art, the treatment of the sputter target after the sputter treatment is discarded, or part of the sputter target is collected for remelting or refining, pulverized and then sintered to produce A new sputter target. However, when the waste target is pulverized by complicated treatment, it takes a lot of time and money. When the waste After the target is pulverized, it may be doped with impurities, which may adversely affect the purification of the final sputter target.

In recent years, with the binding obligations of international conventions indicating the reduction of greenhouse gases that cause global warming effects (the main purpose of which is to reduce the average emissions of carbon dioxide by 5% from 2008 to 2012, it is the Kyoto Protocol since 1990). The first reduction period), however, the Convention has expired, and the United Nations Environment Program (UNEP) has spared no effort to extend the contract until 2020. The Emissions Trading System (ETS) will be introduced in 2015, so countries can only continue their industrial activities without leaving the traditional methods of industrial architecture and meeting the requirements of the International Environmental Organization. However, in the conventional powder disposal of waste targets, the use of strong acid causes the process to be in a high-risk condition and produces a significant amount of liquid after use, thereby causing environmental hazards.

The present invention is directed to regenerating a waste sputter target that is filled and sintered with a raw material powder through an environmentally friendly and economical process.

However, when the raw material powder is filled in the waste sputtering target for regenerating the waste sputtering target, the remaining portion (reuse portion) of the discarded sputtering target and the newly filled portion of the discarded sputtering target , different grains may grow, resulting in instability of the interface between the reused portion and the filled portion.

Therefore, according to an embodiment of the present invention, the raw material powder is filled in the waste sputter target, and the mold is molded at a predetermined pressure before sintering the raw material powder. In order to lower the sintering temperature thereof, it is easy to control the remaining crystal grains of the interface between the waste sputtering target and the new filler powder portion, so that the uniformity is increased and sputtering with fine crystal grains is obtained. Target.

The invention discloses a method for regenerating a waste sputtering target, comprising: S1) removing one impurity on a surface of the waste sputtering target; and S2) placing the waste sputtering target for removing the impurity into a a mold; S3) filling and planarizing a raw material powder in the waste sputtering target placed in the mold to form a laminate; S4) pressing the laminate to form a molded body; and S5) sintering the mold Body.

The sputtering target may be a waste metal target or a waste alloy target formed by an element selected from the group consisting of gold (Au), silver (Ag), and platinum (Pt). a group consisting of ruthenium (Ru), ruthenium (Ta), cobalt (Co), and tungsten (W); the waste alloy target is composed of two or more elements.

The raw material powder can be manufactured by a method comprising: placing a raw material into a mold; subjecting the raw material to a plasma treatment to form a main raw material powder; and placing the main raw material powder in a coating The bed of the same raw material composition is clothed, and then the main raw material powder is ground in a jet mill to form a second raw material powder.

Step S4 can be carried out at a pressure of 100 to 300 MPa for 1 to 60 minutes.

Step S5 can be carried out at a temperature of 700 to 2000 ° C and a pressure of 10 to 80 MPa for 1 to 20 hours.

Embodiments of the present invention provide a sputtering target that utilizes Regenerated by the above method.

The sputtering target may be a metal target or an alloy target formed by an element selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), and ruthenium. a group consisting of (Ru), tantalum (Ta), cobalt (Co), and tungsten (W); the alloy target is composed of two or more elements.

The sputter target can be used to form a thin film layer of a semiconductor or a magnetic recording device medium.

According to the regeneration method of the waste sputtering target according to the embodiment of the present invention, a raw material powder is filled in the waste sputtering target, and then molded and sintered at a predetermined pressure to lower the sintering temperature, thereby being easily Controlling the growth of the die on the interface between the remaining portion of the spent sputtering target and the new filled portion of the discarded sputtering target causes the spent sputtering target to regenerate a sputtering target having minute grains.

Compared to the production of new sputter targets, the above-described regeneration method uses less raw material powder, which reduces the manufacturing cost of the sputter target and the short acid production time. According to the disclosure of the present invention, the discarded sputter target which is generally discarded is reused, and the production time of the sputter target is shortened, resulting in a decrease in the amount of carbon dioxide emissions, and the disclosure of the present invention is environmentally friendly.

The above summary is for illustrative purposes only and does not limit the scope of the invention. Moreover, in addition to the illustrative concepts, further aspects, embodiments, and technical features are described in more detail in the description and drawings below.

1 is a flow chart of a method for recycling a waste sputtering target according to an embodiment of the present invention.

2 is a FESEM image of a regenerated sputter target according to Example 1.

3 is a FESEM image of a sputtering target of Comparative Example 1.

4 is a FESEM image of the regenerated sputter target of Example 2.

Fig. 5 is a FESEM image of a sputtering target of Comparative Example 2.

6 is a schematic view showing film thickness and deposition time at a power of 500 W when the film formed by the sputtering target of Example 1 and Comparative Example 1 is used; wherein KJLC refers to the sputtering target of Comparative Example 1, and HeeSung Refers to the sputtering target of Example 1.

7 is a schematic view showing film thickness and deposition time at a power of 1000 W when the film formed by the sputtering target of Example 1 and Comparative Example 1 is used; wherein KJLC refers to the sputtering target of Comparative Example 1, and HeeSung Refers to the sputtering target of Example 1.

8 is a schematic view showing film thickness and deposition time at a power of 1500 W when the film formed by the sputtering target of Example 1 and Comparative Example 1 is used; wherein KJLC refers to the sputtering target of Comparative Example 1, and HeeSung Refers to the sputtering target of Example 1.

9 is a schematic view showing the sheet resistance of the film when the film formed by the sputtering target of Example 1 and Comparative Example 1 is used; wherein KJLC refers to the sputtering target of Comparative Example 1, and the HeeSung refers to the embodiment. 1 splash target.

Figure 10 is formed using the sputtering target of Example 2 and Comparative Example 2-4. Schematic diagram of film thickness and deposition time at 500 W power in the film; wherein KJLC refers to the sputtering target of Comparative Example 2, HeeSung-R refers to the sputtering target of Example 2, and HeeSung-P refers to comparison The sputtering target of Example 3 and Ref. refer to the sputtering target of Comparative Example 4.

11 is a schematic view showing film thickness and deposition time at a power of 1000 W when the film formed by the sputtering target of Example 2 and Comparative Example 2-4 is used; wherein KJLC refers to the sputtering target of Comparative Example 2, HeeSung-R refers to the sputtering target of Example 2, HeeSung-P refers to the sputtering target of Comparative Example 3, and Ref. refers to the sputtering target of Comparative Example 4.

12 is a schematic view showing film thickness and deposition time at a power of 1500 W when the film formed by the sputtering target of Example 2 and Comparative Example 2-4 is used; wherein KJLC refers to the sputtering target of Comparative Example 2, HeeSung-R refers to the sputtering target of Example 2, HeeSung-P refers to the sputtering target of Comparative Example 3, and Ref. refers to the sputtering target of Comparative Example 4.

Figure 13 is a schematic view showing the corresponding resistance of the sheet resistance of the film when the film formed by the sputtering target of Example 2 and Comparative Example 2-4 is used; wherein KJLC refers to the sputtering target of Comparative Example 2, HeeSung-R system The sputtering target of Example 2, HeeSung-P means the sputtering target of Comparative Example 3, and Ref. means the sputtering target of Comparative Example 4.

14A and 14B are respectively an image view of the waste gold (Au) sputtering target used in Example 1, and a thickness diagram for measuring the thickness of the waste gold target.

15A and 15B are respectively an image view of a waste ruthenium (Ru) sputtering target used in Example 2 and a thickness diagram for measuring the thickness of the waste ruthenium target.

In the following detailed description, please refer to the illustration. The illustrative embodiments, the drawings, and the claims are not intended to limit the invention. Any changes made without departing from the spirit and scope of the invention may be practiced.

Hereinafter, embodiments of the present invention will be described.

According to an embodiment of the present invention, a method for regenerating a waste sputtering target is obtained by filling the raw material powder with the waste sputtering target and then sintering the mold at a predetermined pressure. Thereby, according to the regeneration method of the waste sputtering target according to the embodiment of the present invention, the sintering temperature is lowered, and thus, it is easy to control the growth of the remaining portion of the waste sputtering target and the interface of the new filler powder portion. The grain causes the waste sputter target to regenerate a sputter target having minute crystal grains.

1 is a schematic diagram of a method for regenerating a waste sputter target according to an embodiment of the present invention, and FIG. 1 for a description of the present invention.

S1) Remove impurities

First, impurities on the surface of the sputter target are removed (hereinafter referred to as step S1).

In general, the waste sputter target used and collected in the sputtering process may be a waste metal target or a waste alloy target formed by an element selected from the group consisting of: a group consisting of gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), tantalum (Ta), cobalt (Co), and tungsten (W); the waste alloy target is composed of two The above elements are composed, but the invention is not limited thereto.

Impurities such as oxides or carbides are present on the surface of the waste metal target, as shown in FIG. Therefore, in this step, impurities can be removed from the waste metal target using a conventional impurity removal method.

For example, a cleaning method such as a cleaning method using acid, alcohol, and/or distilled water, an ultrasonic cleaning method, and a surface plasma cleaning method are used to remove impurities such as oxides or carbides. The surface of the waste metal target is subjected to surface polishing, such as using a machine such as CNC, MCT, or a polisher to remove the impurity, and the surface of the waste metal target is about 1 mm or less ( Preferably, it is about 0.1 to 1 mm). Under this circumstance, if the surface thickness of the removed surface is too small, the impurity cannot be removed as desired, and if the thickness is too large, the filling material is increased, and the remanufacturing cost is also increased.

S2) placing the waste sputtering target from which the impurity has been removed

In step S1, the waste sputtering target from which the impurities are removed is placed in a mold (hereinafter referred to as step S2).

The material for the mold is not particularly limited in this step, and is, for example, a steel grade for a steel tool mold, SKD, or STD or a steel grade for stainless steel.

S3) filling and planarizing the raw material powder to form a laminate

Next, a raw material powder is filled in the waste sputtering target placed in the mold as described in step S2, and planarized to form a laminate (hereinafter, referred to as step S3).

Generally speaking, the sample of the raw material powder used in this step is a metal powder or an alloy powder, and the metal of the metal powder is selected from the group consisting of gold (Au) and silver. a group consisting of (Ag), platinum (Pt), ruthenium (Ru), ruthenium (Ta), cobalt (Co), and tungsten (W); the alloy powder is composed of two or more metals, but the present invention Not limited to this. However, the raw material powder needs to be consistent with the material of the waste sputter target.

The content (filling amount) of the raw material powder can be further calculated and adjusted by the density calculation method of the waste sputtering target and the desired re-sputtering target after removing the impurities in the step S1. For example, when the weight of the desired sputter target 3 kg and the waste sputter target is 1.5 kg, the waste sputter target is reconstituted with 2 kg of the raw material powder. In this example, 0.5 kg will be removed in the final process.

The raw material powders can be produced by the following methods, but the powder sputtering target can be obtained by powdering by a conventional drying method or a wet method in addition to the following methods.

For example, the raw material powder can be produced by a method comprising the steps of: placing a raw material into a mold (step S31), subjecting the raw material to a plasma treatment to form a main raw material powder (step S32), and The main raw material powder is deposited on a substrate coated with the same raw material component, and then the main raw material powder is ground in a jet mill to form a second raw material powder (step S33). The method is a novel drying method, and when the raw material powder is produced from the waste sputtering target by this method, the method disclosed in the present invention can shorten the production time of the raw material compared to the conventional wet method. The process is safe and environmentally friendly. It is possible to produce a raw material powder containing fine crystal grains which is high in purity compared to the conventional drying method.

First, the material is placed in a mold (or a) Plasma treatment is performed (step S31).

The raw material may be a bulk sputtering target itself or a bulk status formed by sintering or melting a metal (alloy). However, when the raw material is the waste sputtering target itself, impurities such as sodium (Na), copper (Cu), carbon (C), or cerium (Si) may be present on the surface of the raw material, or The surface may be oxidized by prolonged exposure to air. Therefore, the waste sputter target needs to be cleaned before being placed in the mold. The method of cleaning the raw material is not particularly limited, but the surface of the discarded sputter target may be cleaned or removed as described in step S1.

At the same time, the material of the mold into which the raw material is placed is not particularly limited. However, when the material of the mold is the same as the material to be placed, the increase of the component (for example, carbon) of the impurity can be prevented, and therefore, an additional environmental thermal process for removing carbon is not required. Reduce the time to make powder.

Thereafter, the raw material placed in the mold in step S31 is subjected to plasma treatment to form the main raw material powder (step S32). As described above, when the plasma treatment is carried out to form a main raw material powder, the raw material powder produced in a short period of time is safe and environmentally friendly as compared with the conventional wet method.

Here, the power, time, and processing vacuum level of the plasma treatment are not particularly limited, but are preferably 5 to 60 Kw (more preferably, 15 to 30 Kw), and the time is 10 to 240 minutes. The vacuum level is 50 to 600 torr. When the plasma treatment procedure is carried out, if the power is lower than 5 Kw, the yield of the raw material powder is reduced, however, if the power exceeds 60 Kw, the grain size of the main raw material powder is increased. Vacuum of processing When the level is lower than 50 torr, the plasma will be widely distributed to shorten the life of the positive mold for forming the plasma; however, if the vacuum level of the processing exceeds 600 torr, the main raw material powder will be crystallized. Increased particle size and increased oxygen content. Therefore, the plasma treatment can be carried out under the above conditions. Preferably, the applied voltage is 50 to 200 V and the applied current is 100 to 300 A, and the plasma may be a direct current (DC) transfer plasma.

When the plasma treatment is carried out under vacuum and an inert gas atmosphere, it prevents oxidation of the main raw material powder. Under such conditions, the inert gas generating an inert environment may be, but not limited to, argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ), methane (CH ₄ ), helium (He), and may be used alone. One of them may be a mixture of at least two of them.

The reaction gas for forming the plasma is not particularly limited, but may be, for example, argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ), methane (CH ₄ ), helium (He), which may be used alone. One of them may be a mixture of at least two of them. In this case, the flow rate of the reaction gas is preferably from 20 to 200 SLM.

The size of the main raw material powder formed by the plasma treatment is not particularly limited, but may be from 1 to 1000 μm. Under such a condition, about 3% of the main raw material powder formed may have a size exceeding 1000 μm, but this can be reused as a raw material.

Next, the main raw material powder formed as described in step S32 is placed on a substrate coated with the same raw material component, and then the main raw material powder is ground in a jet mill to form a second raw material. Powder (step S33). When the second raw material powder is formed by grinding in a jet mill, A raw material powder having a smaller grain size than the conventional drying method can be produced. The substrate coated with the same raw material component is used in a jet mill to reduce impurities (such as iron (Fe), chromium (Cr), nickel (Ni)) derived from the substrate and the raw material powder, which is mixed with The base material made of stainless steel is different, and a high-purity raw material powder can be obtained.

The type of gas used in the jet mill is not particularly limited, but may be, for example, one of argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ), helium (He) or the like. At least two or more mixtures. The gas source does not contain oxygen, thereby preventing the occurrence of oxidation of the powder, and thus preventing the surface energy from increasing when the second raw material powder is formed. The speed of the blade to be ground in the jet mill is not particularly limited, but if the speed is about 1,000 to 20,000 rpm, the grinding time can be shortened. When the grinding gas pressure is 5 to 10 bar, the grinding time can also be shortened.

The crystal grain size of the second raw material powder formed in the jet mill is not particularly limited, but may be about 10 μm or less, preferably about 0.1 to 10 μm.

Alternatively, the second raw material powder formed by the step S33 may be subjected to a hydrogen reduction heat treatment. As described above, when the hydrogen reduction heat treatment is applied to the second raw material powder, the oxygen or nitrogen in the second raw material powder may be removed to increase the purity of the second raw material powder.

The conditions of the hydrogen reduction heat treatment are not particularly limited, and are preferably carried out at 500 to 1,000 ° C for 2 to 10 hours in a hydrogen atmosphere. If the hydrogen reduction heat treatment is insufficient for the aforementioned time and temperature range, the oxygen and hydrogen are not sufficiently removed, and if the hydrogen reduction heat treatment exceeds The powder will aggregate during the aforementioned time and temperature range.

The mold used for the hydrogen reduction heat treatment is not particularly limited, but may be, for example, alumina (Al ₂ O ₃ ), stainless steel series, tantalum (Ta), molybdenum (Mo), tungsten (W), Zirconium dioxide (ZrO ₂ ) or bismuth trioxide (Y ₂ O ₃ ). Here, the mold selected from the group consisting of alumina (Al ₂ O ₃ ), zirconium dioxide (ZrO ₂ ) or antimony trioxide (Y ₂ O ₃ ) is oxygen-stable (oxi- Stabilized), and therefore the raw material powder is not oxidized (the oxide content does not increase). The gas used for the hydrogen reduction heat treatment is not particularly limited, but may be, for example, hydrogen (H ₂ ), nitrogen (N ₂ ), argon (Ar), and helium (He) or a mixture of at least two of them. .

The raw material powder prepared as described above is filled in the sputtering target and then planarized. In such a case, in order to reduce the deviation value of the thickness of the final sputtering target, the sputtering target filled with the raw material powder can be adjusted to a level of ±0.1 mm or less at the level of planarization.

S4) forming a molded body

A voltage is applied to the laminate produced in the step S3 to form a molded body (herein, referred to as step S4). The sintering temperature in step S5 can be lower than the temperature in step S4, so that the crystal grains grown in the interface between the reused portion and the newly filled regenerated sputtering target can be controlled. Specifically, the portion of the reused portion of the waste sputter target that is regenerated by the step S5 is coarse particles, and the crystal grains of the filled portion are finer. However, the die of the interface between the reused portion and the filled portion can be adjusted to be less than 30% of the reused portion, so as to prevent the use of the re-use and the filling portion due to the difference in grain size. Separation phenomenon, and therefore High density target.

The method of forming the molded body is not particularly limited, but may be, for example, by a compression molding method or a cold isostatic molding method.

The pressure conditions as described in step S4 are not specifically limited, but if the time is about 1 to 60 minutes and the pressure is between 100 and 300 MPa, the relative density of the molded body may be maintained while maintaining the target type. increase.

S5) Sintered molded body

The molded body obtained in the step S4 is sintered (herein, referred to as step S5).

The method of sintering the molded body is not particularly limited and may be, for example, a hot pressing method, a heat equalizing method, a spark plasma sintering method, or a gas pressure sintering method. In the above method, when the molded body is sintered by hot pressing, it can be reduced to be lower than oxidation of the powder in the molded body.

The burning condition of the molded body is not particularly limited. However, if the sintered body is sintered at a pressure of 10 to 80 MPa and a temperature of about 700 to 2000 ° C for 1 to 20 hours, a target having a high relative density and a small grain size can be produced. Preferably, the sintering temperature may be lower than 80% of the melting point (Tm) of the sputtering target material.

The material of the mold for sintering the mold body is not particularly limited and may be, for example, carbon (C), molybdenum (Mo), tungsten (W), tantalum (Ta), niobium (Nb), zirconium (Zr) or platinum ( Pt), which may be used singly or in combination of at least two of them.

However, the present invention provides a sputtering target which is regenerated by the aforementioned regeneration method.

In the case of the regenerated sputtering target, the newly filled crystal grains are fine, but the grains in the reused portion are coarser than the grains in the filled portion. However, as disclosed in the present invention, the crystal grains grown on the interface between the filling portion and the recycling portion can be adjusted to discard the crystal grains on the sputtering target layer during the regeneration using the above-described regeneration method. 30% or less makes it possible to prevent the separation of the interface between the filled portion and the reused portion due to the difference in grain size, and therefore the regenerated sputter target of the present invention can be suitably used in the regeneration process.

The regenerated sputter target according to the present invention has fine crystal grains such that when the regenerated sputter target is applied to the sputtering process, product uniformity is increased and particle formation is suppressed to reduce the defect rate of the product.

The regenerated sputter target can be a sputter target for forming a thin film layer of a semiconductor or a magnetic recording device medium (eg, a hard disk), and more suitable for forming a circuit in a semiconductor process. The regenerated sputter target can be used to produce compounds, hardened materials, electrical contact materials, resistive materials, catalytic materials, or photosensitive or anti-black materials.

In the following, specific embodiments of the invention are described in detail, but such embodiments are not intended to limit the scope of the invention.

Example 1

1-1 production of raw material powder

The target material was sputtered by cutting a target of 2 kg of waste gold (Au) having a purity of 4 N or more by a cutting tool, and then immersing it in alcohol for 5 minutes to wash away the waste gold sputtering target. The cleaned gold sputter target was inserted into a gold mold that was attached to a 60 kW direct current (DC) transfer plasma apparatus. Next, a vacuum pump is attached to the plasma apparatus to decompress it to 10 ^-2 torr, and is set to be processed using a mixed reaction gas (gas flow rate of 150 SLM) of nitrogen (N ₂ ) and argon (Ar). Vacuum level (200 torr), and the plasma is formed using a plasma reaction gas (gas flow rate of 50 SLM) formed of nitrogen (N ₂ ), argon (Ar), and hydrogen (H ₂ ), and using a power of 15 kW. Gold powder is produced (the size of the center crystal grain is 50 μm or less).

1-2 Sputtering target production

The surface of the waste gold sputter target having a purity of 4 N or more (see FIG. 14) was immersed in hydrochloric acid (HCL) for 5 minutes to clean the discarded gold sputter target. 1.5 kg of the cleaned gold sputter target was inserted into the mold, and then 2.0 kg of the gold powder prepared in Example 1-1 was filled to flatten the surface and the horizontal surface level was within ±0.1 mm. And get a stack. Thereafter, the laminate was pressed and molded under a pressure of 180 MPa for 10 minutes, and then a molded body was obtained, and then the molded body was separated from the mold. Next, the separated molded body was subjected to hot press sintering at a temperature of 800 ° C and a pressure of 20 MPa for 12 hours to produce a gold sputtering target.

Example 2

2-1 production of raw material powder

The waste ruthenium (Ru) sputtering target having a purity of 3 N5 or more was cut by a cutting tool, and then immersed in sodium hypochlorite (NaClO) for 5 minutes, and then the waste ruthenium sputtering target was cleaned. The cleaned sputter target was inserted into a die that was attached to a 60 kW direct current (DC) transfer plasma device. Next, a vacuum pump is attached to the plasma apparatus to reduce it to a pressure of 10 ^-2 torr, and a mixed reaction gas (gas flow rate of 150 SLM) of nitrogen (N ₂ ) and argon (Ar) is used to The processing vacuum level (200 torr), and the plasma is formed using a plasma reaction gas (gas flow rate of 50 SLM) formed of nitrogen (N ₂ ), argon (A _r ), and hydrogen (H ₂ ), and using 15 kW. The power produces a major powder.

Next, the main tantalum powder obtained by the foregoing steps is deposited on a coated crucible substrate (stainless steel is coated with tantalum powder) and then classified by a jet mill to produce a second tantalum powder. Under such conditions, when ground in a jet mill, the gas source was nitrogen (N ₂ ), the grinding gas pressure was 7 bar, and the classified blade speed was 2,000 rpm.

Next, the second tantalum powder was subjected to a hydrogen reduction heat treatment in which a molybdenum (Mo) mold was used at 900 ° C for 8 hours to give a final tantalum powder (the size of the central crystal grains was 10 μm or less).

2-2 Sputtering target production

The sputtering target was fabricated as described in Example 1-2, except that 1.5 kg of the spent gold sputter target used in Example 1-2 was replaced with a 1.5 kg spent ruthenium sputter target (see Figure 15), and 2.0 kg of strontium powder obtained in Example 2-1 was used instead of 2.0 kg of gold powder.

Comparative example 1

Comparative Example 1 used a gold sputtering target (EJTAUX X404A4, 4N) of KJLC, Germany, which was produced by a wet method.

Comparative example 2

Comparative Example 2 used a ruthenium sputter target (EJTRUX X 354A2, 3N5) of KJLC, Germany, which was produced by a wet method.

Comparative example 3

The tantalum powder prepared in Example 2-1 was filled in a carbon mold, and sintered at a pressure of 30 MPa and a temperature of 1500 ° C for 3 hours to produce a tantalum sputtering target. Under such circumstances, in order to induce sufficient degassing, the pressure is applied at a minimum pressure and the rate of temperature rise is adjusted to 5 ° C or lower.

Comparative example 4

Comparative Example 4 used a ruthenium sputtering target produced by Heraeus.

Experimental example 1

The cross-sections of the sputter targets in Examples 1 and 2 and Comparative Examples 1 and 2 were examined by field emission scanning electron microscopy (FESEM), and the results are shown in Figures 2 to 5.

As shown in FIGS. 2 and 3, the crystal grain shape of the gold sputtering target of Example 1 was approximately the same as that of the gold sputtering target shown in Comparative Example 1. However, the gold sputter target of Example 1 has a crystal grain size of about 44 μm and a crystal grain size smaller than that of the gold sputter target of Comparative Example 1 (the average crystal grain size is about 54 μm). .

The crystal grain shape of the tantalum sputtering target of Example 2 was approximately the same as that of the tantalum sputtering target shown in Comparative Example 2 (see FIGS. 4 and 5).

Experimental example 2

In order to confirm the impurity content and purity in the sputtering target manufactured by the waste sputtering target of the present invention, in Examples 1, 2, and Comparative Examples 1, 2, it was analyzed by Inductively Coupled Plasma (IPC). And record the results in Tables 1 and 2 below. As shown in Tables 1 and 2 below, the filled portion indicates the portion where the raw material powder is filled, and the reused portion indicates the portion where the waste sputtering target is used but the raw material powder is not filled, and the interface portion is indicated in the filled portion and the portion Reuse the interface between the parts.

As shown by the measurement results, the purity of the filling portion, the interface portion, and the reuse portion of the gold sputtering target in Example 1 was the same as that of the gold sputtering target shown in Comparative Example 1. However, the total impurity in Example 1 was lower than that of the gold sputter target of Comparative Example 1 (see Table 1).

As shown in the second embodiment of the sputtering target, the total impurity in the second embodiment is lower than that of the sputtering target of the second embodiment, and the purity of the filling portion, the interface portion, and the reuse portion. The tantalum sputtering target shown in Comparative Example 2 was the same.

As described above, even when the sputtering target is produced by the recycling portion disclosed in the present invention, it can be confirmed that the sputtering target is not contaminated.

Experimental example 3

In order to confirm the performance of the sputtering target produced by the waste sputtering target according to the present invention, sputtering treatments were carried out using Examples 1 and 2 and Comparative Examples 1 to 4. Under such conditions, the thickness of the film is measured according to the deposition time of 500 W, 1000 W, and 1500 W, and the sheet resistance (Ω/sq.) of the film is measured based on the change in power. The SME-200E from ULVAC is used as a sputtering device. The measurement results are recorded in Figures 6 to 13.

As shown in FIGS. 6 to 8, in the gold sputtering target of the first embodiment, the film formed by each of the above powers has substantially the same thickness as the gold sputtering target of Comparative Example 1. In the gold sputter target of Example 1, even if the power supplied was different, the sheet resistance of the formed film did not change, and the result was different from that of the gold sputter target of Comparative Example 1 (see Fig. 9).

In the example of the tantalum sputtering target in the second embodiment, the thickness of the film is the same as that of the sputtering targets of Comparative Examples 2 to 4, and the sheet resistance of the film formed is also disclosed in Comparative Examples 2 to 4. The sputtering target is similar (see Figures 10 to 13).

It is to be understood that the above-described embodiments are merely illustrative for the sake of convenience of description, and the scope of the claims is intended to be limited by the scope of the claims.

Claims (8)

A method for regenerating a waste sputtering target, comprising: S1) removing one impurity on a surface of the waste sputtering target; and S2) placing the discarded sputtering target to remove the impurity into a mold; S3 Filling and planarizing a raw material powder to form a laminate in the waste sputtering target placed in the mold; S4) pressing the laminate to form a molded body; and S5) sintering the molded body. The recycling method according to claim 1, wherein the waste sputtering target is a waste metal target or a waste alloy target, and the waste metal target is selected from one of the following groups: Forming: a group consisting of gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), tantalum (Ta), cobalt (Co), and tungsten (W); It consists of two or more elements. The method of claim 1, wherein the raw material powder is produced by a method comprising: placing a raw material into a mold; and subjecting the raw material to a plasma treatment to form a main raw material powder; and the main raw material powder is placed on a substrate coated with the same raw material component, and then the main raw material powder is ground in a jet mill to form a second raw material powder. The regeneration method according to claim 1, wherein the step S4 is carried out at a pressure of 100 to 300 MPa for 1 to 60 minutes. The regeneration method according to claim 1, wherein the step S5 is carried out at a temperature of 700 to 2000 ° C and a pressure of 10 to 80 MPa for 1 to 20 hours. A sputtering target which is regenerated by a method according to any one of claims 1 to 5. The sputtering target according to claim 6, wherein the sputtering target is a metal target or an alloy target, and the metal target is formed by an element selected from the group consisting of: a group consisting of gold (Au), silver (Ag), platinum (Pt), ruthenium (Ru), ruthenium (Ta), cobalt (Co), and tungsten (W); the alloy target is composed of two or more types The composition of the elements. The sputter target of claim 6, wherein the sputter target is used to form a thin film layer of a semiconductor or a magnetic recording device medium.