KR20160105304A - Sputtering target and manufacturing method of sputtering target - Google Patents

Abstract

The purpose of the present invention is to provide a sputtering target, having an increased durability and restraining arching during sputtering. According to the present invention, the sputtering target comprises: a target member where a ratio of presence per unit area of an organic substance is equal to and not more than 15.8% on a surface thereof; and a base material bonded to the target member through an adhesive material. Moreover, the ratio of presence of the organic substance can comprise silicon. Moreover, the target member and the base material can have a cylindrical shape.

Description

[0001] SPUTTERING TARGET AND MANUFACTURING METHOD OF SPUTTERING TARGET [0002]

The present invention relates to a sputtering target and a manufacturing method thereof. Particularly, it relates to the surface state of the sputtering target.

2. Description of the Related Art In recent years, a flat panel display (FPD) manufacturing technology and a manufacturing technology of a solar cell have rapidly developed, and a large-sized thin television and a solar cell market are increasing. In accordance with the development of such a market, a glass substrate is being made larger in order to reduce manufacturing cost of products. Currently, development of a device for a size of 2200 mm x 2400 mm called the eighth generation is underway.

Particularly, in a sputtering apparatus for forming a metal thin film or a metal oxide thin film on a large glass substrate, a flat sputtering target or a cylindrical (also called a rotary or rotary type) sputtering target is used. The cylindrical sputtering target has an advantage that the use efficiency of the target is higher than that of the flat sputtering target, the occurrence of corrosion is small, and generation of particles due to separation of the deposit is small.

When a thin film is formed by the sputtering method, when particles are generated, the pattern may be defective or the like. The most common cause of such particles is an abnormal discharge (arcing) which occurs during sputtering. Particularly, when arcing occurs on the target surface, the peripheral target material in which arcing occurs is released from the target in a cluster shape (lump shape) and adhered to the substrate.

Unevenness (surface roughness) of the target surface is generally known as a parameter that affects occurrence frequency of arcing. For example, as shown in Patent Documents 1 to 3, a surface treatment technique for reducing surface roughness of a target in order to suppress occurrence of arcing has been developed.

Patent Document 1: JP-A No. 2005-002364 Patent Document 2: JP-A-2003-055762 Patent Document 3: JP-A-10-298743

However, even if the surface roughness of the target is reduced by performing the surface treatment, it is difficult to sufficiently suppress the arcing. Therefore, it is necessary to perform pre-sputtering for continuing film formation on the dummy substrate until the number of arcing is reduced and stabilized after the target is mounted on the sputtering apparatus and vacuum evacuation is performed. This free sputtering not only delays the time at which the state of the sputtering apparatus reaches the operating state in the production line but also shortens the period (target life) in which the target can be used because it consumes the target.

As a result of repeated studies by the present inventors in view of the above-mentioned facts, it has been found that, as parameters affecting occurrence frequency of arcing, besides the surface roughness of the target, the organic matter mass entering the concave portion of the target surface is related. This organic material is an insulator, which is charged by electrons emitted from the plasma in sputtering, and its charge amount causes arcing as a name. Further, since the organic material is contained in the concave portion of the target surface, the presence of the organic material can not be noticed when the surface treatment of the target is performed using the surface roughness of the target as an index. Therefore, the period of free sputtering until the sputtering apparatus reaches the operating state in the production line becomes longer.

An object of the present invention is to provide a sputtering target having a long life span while suppressing arcing during sputtering.

A sputtering target according to an embodiment of the present invention has a target member in which the existence ratio of the organic material on the surface per unit area is 15.8% or less and a substrate bonded to the target member via the bonding material.

Further, in another form, the organic material may comprise silicon.

Further, in another form, the target member and the substrate may be cylindrical.

In another aspect, the target member may be formed of ITO (Indium Tin Oxide).

In another aspect, the target member may be made of IGZO (Indium Gallium Zinc Oxide).

In another aspect, the target member may be made of IZO (Indium Zinc Oxide).

In another aspect, the surface roughness (Ra) of the target member may be less than 0.5 占 퐉.

A method of manufacturing a sputtering target according to an embodiment of the present invention is a method of manufacturing a sputtering target, comprising: bonding a target member whose surface is covered with a film-like resin to a substrate via a bonding material; peeling the film- The target member is ground so that the ratio of the organic material contained in the shape resin per unit area is 15.8% or less.

Further, in another form, the grinding can grind the target member at least 0.15 mm from the surface.

Further, in another form, the organic material may comprise silicon.

In another aspect, the grinding can be performed so that the surface roughness (Ra) of the target member is less than 0.5 占 퐉.

According to the present invention, arcing during sputtering can be suppressed, and a sputtering target having a long life can be provided.

1 is a perspective view showing an example of a cylindrical sintered body constituting a cylindrical sputtering target according to an embodiment of the present invention.
2 is a cross-sectional view showing an example of the configuration of a cylindrical sputtering target after assembly according to an embodiment of the present invention.
3 is a process flow chart showing a method of manufacturing the sputtering target 100 according to an embodiment of the present invention.
4 is a graph showing the correlation between the ratio of the organic material present on the surface of the sputtering target and arcing occurrence number according to an embodiment of the present invention.
5 is an SEM image of a target surface immediately after peeling off a masking tape in a sputtering target according to an embodiment of the present invention.
Fig. 6 is an SEM image of the target surface shown in Fig. 5 further enlarged.
7 is a cross-sectional view taken along the line A-B of the SEM image shown in Fig.
8 is a SEM-EDX mapping image of a target surface immediately after peeling off a masking tape in a sputtering target according to an embodiment of the present invention.
FIG. 9 is an EDX spectrum showing the SEM-EDX analysis result of measuring the brightly visible portion of the SEM-EDX mapping image shown in FIG.
Fig. 10 is an SEM-EDX mapping image of the target surface in which the existence ratio of the organic material on the target surface is 10.2%, among the graph shown in Fig.
11 is a SEM-EDX mapping image of a target surface in which the existence ratio of the organic material on the target surface is 15.8%, among the graphs shown in Fig.
Fig. 12 is a SEM-EDX mapping image of the target surface in which the existence ratio of the organic material on the target surface is 38.5%, among the graph shown in Fig.
13 is a SEM-EDX mapping image of the target surface in which the existence ratio of the organic material on the target surface is 52.3%, among the graph shown in Fig.
Fig. 14 shows experimental results comparing the number of arcing occurrences with the target surface roughness and the ratio of organic substances present in Examples and Comparative Examples.
15 is an SEM image of a target surface immediately after peeling off a masking tape in an IGZO sputtering target according to an embodiment of the present invention.
16 is an SEM image of the target surface immediately after peeling off the masking tape in the IZO sputtering target according to one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. It should be noted, however, that the present invention can be carried out in various forms without departing from the gist of the present invention, and the present invention is not limited to the contents of the embodiments described below.

For the sake of clarity, the drawings are schematically illustrated with respect to the width, thickness, shape, and the like of the corner portions in comparison with the actual shapes, but they are merely examples and do not limit the interpretation of the present invention. In addition, elements having the same functions as those described with reference to the drawings already described in the present specification and drawings are denoted by the same reference numerals, and redundant explanations can be omitted.

In the following embodiments, a cylindrical sputtering target is described as an example of a sputtering target. However, the present invention is not limited to a cylindrical sputtering target, and may be applied to a flat sputtering target.

In the following description, the density of the molded body and the density of the sintered body are expressed by relative densities. Relative density is expressed by relative density = (measured density / theoretical density) x 100 (%), depending on the theoretical density and the measured density. The theoretical density is a density value which is calculated from using the raw material, the indium oxide 90% by mass, when the tin oxide is a raw material was weighed so that 10 mass%, (In ₂ O ₃ Density ^{(g / cm 3) × 90} + of SnO ₂ of Density (g / cm < ³ >) x 10) / 100. The density of In ₂ O ₃ has a density of 7.18g / cm ^3, SnO ₂ is calculated to be 6.95g / cm ^3, the theoretical density is calculated to be 7.15 (g / cm ^3). On the other hand, the measurement density is a value obtained by dividing a weight by a volume. In the case of a molded body, the volume is calculated by measuring the dimensions. In the case of the sintered body, the volume is calculated according to the Archimedes method.

The difference between the sintered bodies represents the difference in relative density. For example, the difference in relative density between sintered body A having a relative density of 99.5% and sintered body B having a relative density of 99.6% is calculated as 99.6% -99.5% = 0.1%. This is because, since the sintered bodies have the same theoretical density when the compositions of the sintered bodies are the same, a difference in density between adjacent sintered bodies can be evaluated by simply calculating a difference. At this time, the maximum value of the difference between the sintered bodies is evaluated by a difference. The sputtering target in the present invention can be applied to an assembly in which sintered bodies of the same composition are arranged side by side.

<Embodiment>

[Configuration of sputtering target]

1 is a perspective view showing an example of a cylindrical sintered body constituting a cylindrical sputtering target according to an embodiment of the present invention. 2 is a cross-sectional view showing an example of the configuration of a cylindrical sputtering target after assembly according to an embodiment of the present invention.

In the present embodiment, a cylindrical sputtering target is exemplified. The sputtering target 100 according to the present embodiment includes a base material 101 and target members 102a and 102b. Each of the target members 102a and 102b is bonded to the base material 101 via the bonding material 103. [ At this time, the bonding material 103 is provided so as to fill the gap provided between the base material 101 and the target members 102a and 102b.

The sputtering target 100 according to the present embodiment has the target members 102a and 102b and the base material 101 bonded to the target members 102a and 102b through the bonding material 103. [ Further, the sputtering target 100 is characterized by the surface state of the sintered body constituting the target members 102a and 102b. Specifically, on the surfaces of the target members 102a and 102b, the organic material exists in a unit area of 15.8% or less (preferably 10.2% or less). This point will be described later.

Here, the existence ratio of the organic material is the ratio of the organic material in the surface state of the target members 102a, 102b of the sputtering target 100 in the distribution step. That is, the existence ratio of the organic material is the existence ratio of the organic material in the surface state of the target members 102a and 102b before the sputtering (before the plasma atmosphere is used or before the sputtering target is used). Here, in the state before performing the sputtering, the surface roughness of the target members 102a and 102b has an average surface roughness (Ra) of less than 0.5 占 퐉.

The target members 102a and 102b are provided so as to surround the outer peripheral surface of the base material 101. [ It is preferable that the target members 102a and 102b are provided on the same axis or substantially the same axis with respect to the central axis of the base material 101. [ With this configuration, when the sputtering target 100 is mounted on the sputtering apparatus and rotated around the substrate 101, the distance between the surface of each of the target members 102a and 102b and the surface (sample substrate) It can be kept constant.

The sputtering target 100 has the target members 102a and 102b disposed at predetermined intervals when the target members 102a and 102b are mounted on the base member 101. [

The sputtering target 100 of the present embodiment can be an elongated sputtering target having a length of 100 mm or more by bonding the target member 102 to the base material 101 via the bonding material 103.

[materials]

It is preferable that the base material 101 has an outer shape along the inner surface of the target members 102a and 102b having a hollow cylindrical shape. As described above, the outer diameter of the base material 101 is slightly smaller than the inner diameters of the target members 102a and 102b, and the gap is adjusted so that when the two are overlapped on the same axis, a gap is generated. A bonding material 103 is provided in this gap.

The base material 101 is preferably a metal which has good wettability with the bonding material 103 and can obtain a high bonding strength between the bonding material 103 and the bonding material 103. Therefore, it is preferable to use, for example, copper (Cu) or titanium (Ti), a copper alloy, a titanium alloy, or stainless steel (SUS) as a material constituting the base material 101. [ As the copper alloy, an alloy containing copper (Cu) as a main component such as chromium copper can be applied. In addition, when titanium (Ti) is used for the substrate 101, a lightweight and rigid substrate 101 can be obtained.

[binder]

The bonding material 103 is provided between the base material 101 and the respective target members 102a and 102b. It is preferable that the bonding material 103 is bonded to the base material 101 and the respective target members 102a and 102b and has good heat resistance and thermal conductivity. Further, since it is put under vacuum during the sputtering, it is preferable that it has a characteristic that the gas emission is small in vacuum.

From the viewpoint of manufacturing, it is preferable that the bonding material 103 has fluidity when bonding the base material 101 and the respective target members 102a, 102b. In order to satisfy such a characteristic, a low melting point metal material having a melting point of 300 캜 or less can be used for the bonding material 103. For example, as the bonding material 103, a metal such as indium or tin or a metal alloy material containing any one of these elements may be used. Specifically, indium or tin alloy, indium-tin alloy, tin-based solder alloy, or the like can be used.

[Target Member]

As shown in Figs. 1 and 2, each of the target members 102a and 102b is formed into a hollow cylindrical shape. Each of the target members 102a and 102b has a thickness of at least several millimeters to several tens of millimeters, and it is possible to use the entire thickness portion as a target member.

When the target members 102a and 102b are mounted on the base 101, the base 101 is inserted into the hollow portions of the target members 102a and 102b, and then the two are joined together via the bonding material 103. That is, the outer diameter of the base material 101 is smaller than the inner diameter (diameter of the hollow portion) of each of the target members 102a and 102b, and the bonding material 103 is provided so as to fill the gap therebetween. In order to stably maintain the respective target members 102a and 102b and the base material 101, there is no space in the bonding material 103 in the gap.

In order to prevent the bonding material 103 from adhering to the surfaces of the respective target members 102a and 102b when filling the gap between the bonding material 103 and the surface of the target members 102a and 102b, After attaching a shape resin (masking tape), the bonding material 103 is filled. As the masking tape, it is preferable to use a material having heat resistance at the melting temperature of the bonding material 103. For example, a polyimide film using a silicone adhesive can be used. The masking tape is peeled off after the target members 102a and 102b are bonded to the base material 101. Here, when the target members 102a and 102b are bonded to the substrate 101, they are processed at a temperature of about 200 캜. Therefore, as the bonding material 103, it is preferable to use a material having heat resistance that does not deteriorate at the bonding processing temperature.

Each of the target members 102a and 102b is formed using various materials capable of forming a sputtering film. For example, the target members 102a, 102b may be ceramic. As the ceramics, a metal oxide, a metal nitride, a sintered body of a metal oxynitride, or the like can be used. As the metal oxide, an oxide of a metal belonging to a typical element such as indium oxide, tin oxide, zinc oxide, or gallium oxide can be used.

Specifically, a compound of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), indium oxide, zinc oxide and gallium oxide A sintered body of a compound selected from a compound of Indium Gallium Zinc Oxide (IGZO) can be used as the target members 102a and 102b.

The above specific example is merely an example, and various kinds of sputtering materials can be used as a target member in the sputtering target according to the present embodiment.

The relative density of each of the target members 102a and 102b may be 99.0% or more and 99.9% or less. Preferably, the relative density of each of the target members 102a and 102b may be 99.7% or more and 99.9% or less. The difference in relative density between the adjacent target member 102a and the target member 102b, that is, the difference in relative density between solids of the target member, may be 0.1% or less. In addition, the relative density of the target member or the molded article according to the embodiment of the present invention is a value evaluated by the Archimedes method.

In addition, the thickness of each of the target members 102a and 102b may be 6.0 mm or more and 15.0 mm or less. The length of each of the target members 102a and 102b in the axial direction of the cylinder may be 150 mm or more and 380 mm or less. Further, the space in the axial direction of the cylinder between the adjacent target member 102a and the target member 102b can be 0.2 mm or more and 0.5 mm or less. Further, the surface roughness of the target member preferably has an average surface roughness (Ra) of 0.5 탆 or less.

Here, a step of bonding the target members 102a and 102b to the substrate 101 and peeling off the masking tape, then removing the masking tape residue on the surfaces of the target members 102a and 102b is performed. The present inventors have found that the masking tape residue remains in the concave portions on the surfaces of the target members 102a and 102b and the masking tape residue filled in the concave portions leads to arcing.

As a result of intensive research, the inventors of the present invention have found that arcing can be suppressed by setting the ratio of the organic material on the surface of each of the target members 102a, 102b to be 15.8% or less per unit area. That is, in the sputtering target 100 according to the present embodiment, the existence ratio of the organic material per unit area on the surfaces of the target members 102a and 102b is 15.8% or less (preferably 10.2% or less).

[About the Presence of Organic Substances]

Here, the calculation method of the ratio of the organic material to the organic material in the unit area will be described in detail. The existence ratio of the organic material in the present embodiment is calculated by detecting characteristic X-rays generated by electron beam irradiation to the surfaces of the target members 102a and 102b. Since the characteristic X-ray energy generated by the electron beam irradiation is element-specific, the element of the object irradiated with the electron beam can be identified by measuring the energy of the characteristic X-ray. Further, information on the composition can be obtained from the signal intensity at each energy value of the characteristic X-ray.

As described above, an energy dispersive X-ray spectroscopy (EDX) method provided in a Scanning Electron Microscope (SEM) can be used as an apparatus for detecting characteristic X- Can be used. The detection sensitivity of EDX is about 1 atomic%. In the case of calculating the ratio of organic substances per unit area using SEM-EDX, the number of total measurement points subjected to EDX measurement (EDX mapping measurement) is denoted by denominator in an area of one frame scanned by SEM. It can be calculated by taking the number of measurement points at which organic substances are detected as molecules.

In the present embodiment, the method using SEM-EDX is exemplified as a method of detecting the presence ratio of organic substances, but the method is not limited to this method. For example, in addition to SEM-EDX, an electron probe micro analyzer (EPMA), wavelength dispersive X-ray spectrometry (WDS), or Auger Electron Spectroscopy (AES) Can be used. In any of the analysis methods, it is possible to calculate the existence ratio of the organic substance based on the result of the mapping measurement of the target element.

In this embodiment, since it is necessary to detect the organic substances remaining in the concave portions of the surfaces of the target members 102a and 102b, it is preferable to evaluate them by SEM-EDX suitable for acquiring information about the surface. It is also preferable to set the acceleration voltage of the electron beam of the SEM to 30 kV or less in SEM-EDX in order to obtain information about the surface of each target member 102a, 102b as much as possible. More preferably, the acceleration voltage of the electron beam of the SEM in SEM-EDX can be set to 20 kV or less. Here, if the acceleration voltage of the electron beam of the SEM is larger than the upper limit, there is a problem that it becomes difficult to acquire information about the surface because the electron beam reaches deeply from the surface of each of the target members 102a and 102b.

Further, in the present embodiment, when silicon (silicon) is detected in SEM-EDX, it is judged that organic material remains on the surface of the target. Since silicon is contained in the pressure-sensitive adhesive (adhesive) of the masking tape, silicon detected on the target surface can be judged as a part of the pressure-sensitive adhesive remaining when the masking tape is peeled off. Thereafter, when there is no special description, the presence ratio of the organic material is used in an equivalent meaning to the ratio of the presence of silicon in SEM-EDX.

Here, in this embodiment, a target not containing silicon as a main component is used. When the present invention is applied to a target member containing silicon as the main component, it is possible to judge whether or not the adhesive of the masking tape remains on the target member by evaluating elements other than silicon among the elements included in the adhesive of the masking tape .

As described above, according to the sputtering target of the present embodiment, occurrence of arcing can be suppressed by making the existence ratio of the organic material in the surface area of the target member 15.8% or less. In addition, it is possible to provide a sputtering target having a long lifetime while suppressing arcing.

[Manufacturing method of sputtering target]

Next, a method of manufacturing the sputtering target 100 according to the present embodiment will be described in detail. 3 is a process flow chart showing a method of manufacturing the sputtering target 100 according to an embodiment of the present invention.

In this embodiment, an example in which the indium tin oxide (ITO) sintered body is used as the target members 102a and 102b is shown, but the material of the sintered body is not limited to ITO, and other metal oxide compounds such as IZO and IGZO may also be used.

First, raw materials constituting the target members 102a and 102b are prepared. In this embodiment, a powder of indium oxide and a powder of tin oxide are prepared (S401, S402). The purity of such a raw material may be usually 2N (99% by mass) or more, preferably 3N (99.9% by mass) or more, and more preferably 4N (99.99% by mass) or more. If the purity is lower than 2N, desired physical properties can not be obtained because the target members 102a and 102b contain a large amount of impurities (for example, decrease in transmittance of the formed thin film, increase in resistance value, generation of particles due to arcing) There may be problems.

Next, the raw material powder is pulverized and mixed (S403). The pulverization and mixing treatment of the raw material powder may be carried out by using a dry method using balls or beads (so-called media) such as zirconia, alumina or nylon resin, a media agitated mill using the balls or beads, a medialess vessel rotary mill, A wet method such as a mill, an air stream mill or the like can be used. In general, the wet method is preferable to the wet method because the wet method has better pulverizing and mixing ability than the dry method.

The composition of the raw material is not particularly limited, but it is preferable to appropriately adjust it according to the composition ratio of the target members 102a and 102b.

Next, the slurry of the raw material powder is dried and granulated (S404). At this time, the slurry can be rapidly dried using rapid dry assembly. Rapid dry assembly can be carried out by adjusting the temperature or air flow of the hot air using a spray drier.

Next, the mixture obtained by the above-mentioned mixing and granulation (pre-baked in the case of pre-baking) is press-formed to form a cylindrical formed body (S405). Through this process, the target member 102a, 102b is formed into a shape suitable for the intended target member 102a, 102b. Examples of the molding process include mold molding, casting molding, and injection molding. However, in order to obtain a complicated shape such as a cylindrical shape, cold isostatic pressing (CIP) or the like is preferable. In molding by CIP, the raw material powder weighed at a predetermined weight is first filled in a rubber mold. At this time, by filling the rubber mold while rocking or tapping, uneven filling of the raw material powder in the mold and voids can be eliminated. The pressure for forming by CIP is preferably 100 MPa or more and 200 MPa or less. By adjusting the molding pressure as described above, in the present embodiment, a cylindrical molded body having a relative density of 54.5% or more and 58.0% or less can be formed. More preferably, by adjusting the molding pressure of the CIP to 150 MPa or more and 180 MPa or less, a cylindrical molded body having a relative density of 55.0% or more and 57.5% or less can be obtained.

Next, the cylindrical formed body obtained in the forming step is sintered (S406). Electric furnaces are used for sintering. The sintering conditions can be appropriately selected depending on the composition of the sintered body. For example, ITO containing 10 wt% SnO ₂ can be sintered in an oxygen gas atmosphere at a temperature of 1400 to 1600 ° C for 10 to 30 hours. When the sintering temperature is lower than the lower limit, the density of the target members 102a and 102b is lowered. On the other hand, if the temperature exceeds 1600 DEG C, the damage to the electric furnace or furnace is large and frequent maintenance is required, and the operation efficiency is significantly lowered. When the sintering time is shorter than the lower limit, the density of the target members 102a and 102b is lowered. The sintering pressure may be an atmospheric pressure or a pressurized atmosphere.

Here, in the case of sintering in an electric furnace, the occurrence of cracks can be suppressed by adjusting the rate of temperature increase and the temperature decrease rate of sintering. Specifically, the heating rate of the electric furnace at sintering is preferably 300 ° C / hour or less, more preferably 180 ° C / hour or less. It is preferable that the temperature lowering rate of the electric furnace at sintering is 600 DEG C / hour or less. In addition, the temperature raising rate or the temperature raising rate may be adjusted so as to change stepwise.

The cylindrical shaped body is shrunk by the sintering process and the temperature is maintained during the temperature rise in order to make the temperature in the furnace uniform before all the materials commonly enter the temperature region where the heat shrinkage starts. As a result, temperature unevenness in the furnace is eliminated, and all the sintered bodies provided in the furnace shrink uniformly. In addition, by setting appropriate conditions for each material, the arrival temperature and the holding time can be stabilized to obtain a sintered body density.

Next, the formed cylindrical sintered body is machined into a desired cylindrical shape using a machining machine such as a plane grinding machine, a cylindrical grinding machine, a lathe, a cutting machine, and a machining center (S407). The machining here is a step of machining the cylindrical sintered body so as to have a desired shape and surface roughness, and finally the target members 102a and 102b are formed through this step.

Regarding the outer surface (sputtered surface) of the target members 102a and 102b, the average surface roughness (Ra) of the surface is preferably 0.5 占 퐉 or less. This can reduce the risk that an electric field is concentrated on the protrusions during sputtering and an abnormal discharge occurs.

Next, the machined cylindrical sintered body (i.e., the target members 102a and 102b) is ultrasonically cleaned in pure water to remove machined grinding residue adhering to the surface of the sintered body. Then, a masking tape is attached to cover the surface of the dried sintered body after the cleaning (S408).

Next, the target members 102a and 102b whose surfaces are covered with the masking tape are bonded to the base material 101 via the bonding material 103 (S409). Particularly, in the case of the sputtering target 100, the cylindrical target members 102a and 102b are formed by bonding a bonding material 103 to a cylindrical base material 101 called a backing tube, As shown in Fig.

For example, when indium is used as the bonding material 103, molten indium is injected into the gap between the target members 102a and 102b and the base material 101. [

Next, the masking tape adhering to the surfaces of the target members 102a and 102b bonded to the base material 101 is peeled off (S410). Subsequently, the surface of the target members 102a and 102b is coated with a dust-free cloth coated with an organic solvent in order to remove the adhesive of the masking tape adhered to the surfaces of the target members 102a and 102b on which the masking tape has been peeled off. Wiping treatment is carried out.

Then, after the wiping process, the target members 102a and 102b are ground from the surface side using sandpaper of # 400 room. This grinding is carried out so that the existence ratio of the organic material contained in the masking tape per unit area is 15.8% or less on the surface of the target members 102a and 102b. The proportion of organic substances present can be calculated by the method described above. After grinding, ultrasonic cleaning is performed for 20 minutes in pure water and dried. Through the above process, the sputtering target 100 according to the present embodiment can be obtained.

As described above, according to the manufacturing method of the sputtering target according to the present embodiment, the sputtering target is grinded until the existence ratio of the organic material on the surface of the target member is 15.8% or less per unit area, . In addition, it is possible to provide a sputtering target having a long lifetime while suppressing arcing.

Example

(Example 1)

In the grinding step (S411) in the process flow shown in Fig. 3, the present inventors fabricated four target members having different grinding amounts, and investigated the correlation between the ratio of the presence of the organic material in each target member and the number of occurrence of the initial accumulated arcing . The term &quot; initial accumulated arcing occurrence count &quot; means the number of arcing occurrences occurring during free sputtering until the sputtering apparatus is mounted on the sputtering apparatus and vacuum exhausted, until the sputtering apparatus reaches the operating state in the production line to be.

Here, the arcing occurring between the free sputtering will be described in detail. In order to mount the sputtering target on the sputtering apparatus, it is necessary to open the vacuum chamber for sputtering. When the vacuum chamber is opened to the atmosphere, water, gas and organic substances in the atmosphere are attached to the inner wall of the vacuum chamber. Similarly, moisture, gas and organic substances in the atmosphere adhere to the surface of the sputtering target. As described above, when the vacuum chamber and the sputtering target surface are pre-sputtered with moisture, gas, and organic substance attached thereto, the electrons emitted from the plasma are charged on the deposit, and arcing is caused by reaching the limit of the charge amount . Therefore, during pre-sputtering, much arcing occurs as compared to the operating state.

The arcing during the free sputtering gradually decreases when the free sputtering is continued, and the frequency of occurrence of the arcing is stabilized in a certain range. Then, when arcing frequency is stabilized, free sputtering is terminated. That is, the number of occurrence of the initial accumulated arcing is the cumulative number of arcing occurrences that occurred during free sputtering.

In this embodiment, the correlation between the presence ratio of the organic material on the target surface and the number of initial accumulated arcing occurrences will be described. Here, the relation between the ratio of the presence of each organic material and the target member is as shown in Table 1.

[Table 1]

Here, the 'grinding amount of the target member' is the grinding amount of the grinding step (S411) in the process flow shown in FIG. In this embodiment, grinding was performed using # 400 radiation protection cloth. The condition of 'no grinding amount of target member' is a target member in which grinding is not performed in S411. That is, the surface of the target member is wiped with an organic solvent after peeling off the masking tape, and ultrasonically cleaned in pure water for 20 minutes and dried. In addition, the 'presence ratio of organic material' is the ratio of the organic material calculated by SEM-EDX per unit area. Here, the SEM-EDX measurement apparatus, measurement conditions, and existence ratio are as follows.

(Device name)

SEM: Electron microscope JSM-6700F (manufactured by JEOL)

EDX: Energy dispersive analyzer JED2200F (manufactured by JEOL)

(Measuring conditions)

Acceleration voltage: 15kV

Output current: 10μA

The calculation method of the existence ratio will be described. In this embodiment, when silicon contained in the adhesive of the masking tape is detected by SEM-EDX, it is judged that an organic substance is present. First, the mapping image of silicon is obtained by EDX mapping measurement. The mapping image has different EDX spectral intensities of silicon depending on the amount of organic material present at each measurement point. Next, the EDX spectral intensity of the silicon in the mapping image is normalized to the highest spectral intensity at 100% for the entire measurement point. Then, it is judged that the organic material exists, and the ratio of the measurement point where the organic material exists is calculated as the ratio of the organic material to the total measurement point.

The sputtering conditions for evaluating the number of times of occurrence of the initial cumulative arcing will be described. The target and sputtering conditions for evaluating the number of times of occurrence of the initial cumulative arcing in this embodiment are as follows.

(Evaluation target)

Target material: ITO (SnO ₂ = 10%)

(Sputtering condition)

Sputtering gas: Ar

Sputtering pressure: 0.6 Pa

Sputtering gas flow rate: 300 sccm

Sputtering power: 4.0 W / cm ²

The results of the evaluation under the above conditions will be described. 4 is a graph showing the correlation between the ratio of the organic material present on the surface of the sputtering target and arcing occurrence number according to an embodiment of the present invention. As shown in Fig. 4, when the ratio of the organic material is reduced from 38.5% to 15.8%, the number of the initial accumulated arcing decreases from 468 times to 60 times. On the other hand, even if the ratio of organic substances is reduced from 15.8% to 10.2%, the number of times of occurrence of the initial accumulated arcing rarely changes only from 60 to 45 times. That is, from the results shown in FIG. 4, it has been found that the number of times of occurrence of the initial accumulated arcing can be largely reduced by reducing the existence ratio of the organic material to at least 15.8% or less. Referring to Table 1, it is possible to largely reduce the number of times of occurrence of the initial accumulated arcing by grinding the target after peeling the masking tape by 0.15 mm or more.

Further, the present inventors conducted an analysis of the target surface in order to elucidate the mechanism of the correlation between the presence ratio of organic materials and the number of times of occurrence of the initial accumulated arcing. Fig. 5 is an SEM image of a target surface after a general surface treatment is performed after peeling off a masking tape in a sputtering target according to an embodiment of the present invention. Fig. The SEM image shown in Fig. 5 was carried out under the above-described measurement conditions. In the SEM image shown in Fig. 5, a bright portion is a convex portion, and a dark portion is a concave portion. As shown in FIG. 5, it is confirmed that a plurality of concave portions 200, 202, and 204 are locally present on the target surface. An SEM image obtained by further enlarging the concave portion 200 is shown in Fig. As shown in Fig. 6, it is confirmed that the concave portion 200 appears darker than the surroundings. In the SEM image, the darker the part, the deeper it is. That is, as shown in FIG. 7 in which a schematic cross-sectional view taken along the line A-B including the recess 200 is drawn, the recess 200 has a shape recessed larger than the periphery thereof.

Next, the results of the EDX mapping measurement of the silicon attributed to the adhesive of the masking tape to the sample of the SEM image shown in Fig. 5 will be described. FIG. 8 is a SEM-EDX mapping image of a target surface after a masking tape has been peeled off and then subjected to general surface treatment in the sputtering target according to an embodiment of the present invention. 9 is an EDX spectrum showing a SEM-EDX analysis result of measuring a bright visible portion of the SEM-EDX mapping image shown in FIG. The mapping image and the EDX spectrum shown in Figs. 8 and 9 were performed under the above measurement conditions.

In a portion that appears bright in the mapping image shown in FIG. 8, a peak 220 attributed to silicon is identified in the EDX spectrum shown in FIG. That is, the part that appears bright in the mapping image is the part where the organic material exists. As shown in FIG. 8, it was confirmed that organic material segregation regions 210, 212 and 214 in which organic substances were locally segregated exist on the surface of the target. 5 and FIG. 8, it is confirmed that the organic material segregation regions 210, 212, and 214 correspond to the recesses 200, 202, and 204, respectively. That is, it has been found that a residue of a pressure-sensitive adhesive containing silicon is present in the concave portion of the target surface.

Here, the SEM-EDX mapping image measured for each of the targets with different organic substance presence ratios shown in Fig. 4 is shown in Figs. 10 to 13. It is confirmed that there is almost no organic substance segregation region in the target in which the presence ratio of the organic substance on the surface shown in Fig. 10 is 10.2%. There are two organic material segregation regions 230 and 232 in the target where the existence ratio of organic substances on the surface shown in Fig. 11 is 15.8%. 12, there is an organic material segregation region in the entire region of the mapping image in the target where the existence ratio of the organic material on the surface is 38.5%. In the case where the existence ratio of the organic material on the surface shown in FIG. 13 is 52.3%, there is a high density organic material segregation region in the entire region of the mapping image.

As a result of evaluating the surface roughness of each of the targets different in the presence ratio of the organic material shown in FIG. 4, there was no significant difference in the surface roughness of the four targets, and the average surface roughness (Ra) . In addition, the apparatus for measuring the surface roughness and the measurement conditions are as follows.

(Device name)

Surface roughness tester, Surftest SJ-301 (manufactured by Mitutoyo)

(Measuring conditions)

JIS2001 standard compliant condition

Measurement length: 4.0 mm (0.8 mm x 5)

Measuring tip material: Diamond

Radius of curvature at tip of measurement part: 2 탆

Measuring force: 0.75 mN

Measurement speed: 0.5 mm / s

As described above, according to the experiment by the present inventors, it has been found that the number of times of occurrence of the initial accumulated arcing can be suppressed by making the existence ratio of the organic material in the surface area of the target member of the sputtering target 15.8% or less. It was also confirmed that the number of times of occurrence of the initial accumulated arcing in the present embodiment was not caused by the surface roughness of the target member.

[Comparison of Example 1 and Comparative Example 1]

The results of comparison between the existence ratio of the organic material, the surface roughness, and the number of occurrences of the initial accumulated arcing with respect to Example 1 and Comparative Example 1 according to the embodiment of the present invention will be described.

FIG. 14 shows experimental results comparing the number of arcing occurrences with the target surface roughness and the ratio of organic substances present in Example 1 and Comparative Example 1. FIG. Examples 1-1 and 1-2 and Comparative Examples 1-1 and 1-2 shown in FIG. 14 correspond to four targets in which the existence ratio of the organic material shown in FIG. 4 is different. Comparative Example 1-3 is a target member subjected to a mirror finishing process instead of the grinding process (S411) in the process flow shown in Fig. That is, the target member is subjected to only the mirror-surface processing for suppressing the surface roughness without grinding after peeling off the masking tape, and ultrasonic cleaning and drying in pure water as described above.

As in Comparative Example 1-3, in the target member subjected to mirror-surface processing instead of grinding, the existence ratio of the organic material was 68.5% and the number of times of occurrence of the initial accumulated arcing was 232, There are many results compared to arcing occurrence. In addition, the surface roughness of the target member of Comparative Example 1-3 was smaller than that of Examples 1-1 and 1-2, and Ra was less than 0.1 占 퐉. As is clear from the results of Comparative Examples 1-3, it is not sufficient to suppress the surface roughness of the target member in order to suppress the number of times of occurrence of the initial accumulated arcing, and the organic substance adhering to the surface of the target member, It has been found that it is important to reduce the existence ratio of the organic material contained in the concave portion of the surface of the member.

(Example 2)

Although the evaluation result of the ITO target member is described in the first embodiment, the same result can be obtained even when other oxide target members are used. For example, it was confirmed that the same result as the ITO target member can be obtained for the IGZO target member. In Embodiment 2, the surface state of the IGZO target member will be specifically described.

15 is an SEM image of a target surface immediately after peeling off a masking tape in an IGZO sputtering target according to an embodiment of the present invention. The SEM image shown in Fig. 15 was carried out under the same measurement conditions as in Figs. 5 and 6.

As shown in Fig. 15, it is confirmed that a plurality of concave portions 300, 302, and 304 exist locally on the target surface. Here, as shown in Fig. 15, the concave portions 300 are formed in the grain boundaries, and the concave portions 302 and 304 are formed in the crystal grains. The diameter of the concave portion is larger than the width of the grooves of the grain boundaries (the distance between crystal grains in a direction orthogonal to the grain boundary extending direction).

Also in the sample shown in Fig. 15, it was confirmed that, similarly to the samples shown in Fig. 5 and Fig. 6, there was a region where the organic material was segregated corresponding to the recess. That is, it was confirmed that a residue of a pressure-sensitive adhesive containing silicon was present in the concave portion of the target surface. As described above, it was confirmed that the organic material enters the concave portion of the IGZO target member in the same manner as the ITO target member. The number of the initial cumulative arcing that occurs due to the organic material entering the concave portion is By reducing the ratio to 15.8% or less.

(Example 3)

In Embodiment 3, the surface state of the IZO target member will be specifically described. 16 is an SEM image of the target surface immediately after peeling off the masking tape in the IZO sputtering target according to one embodiment of the present invention. The SEM image shown in Fig. 16 was carried out under the same measurement conditions as in Figs. 5 and 6.

As shown in Fig. 16, it is confirmed that a plurality of concave portions 310, 312, and 314 are locally present on the target surface. Here, as shown in Fig. 16, the concave portions 312 and 314 are formed in the grain boundaries, and the concave portion 310 is formed in the crystal grain. The diameter of the concave portion is larger than the width of the groove of the grain boundary system.

As for the sample shown in Fig. 16, it was confirmed that, similarly to the samples shown in Fig. 5 and Fig. 6, there was a region where the organic material was segregated corresponding to the concave portion. That is, it was confirmed that a residue of a pressure-sensitive adhesive containing silicon was present in the concave portion of the target surface. As described above, it was confirmed that the organic material enters the concave portion of the IZO target member in the same manner as the ITO target member and the IGZO target member, and the number of the initial cumulative arcing that occurs due to the organic material contained in the concave portion, To 15.8% or less in terms of the ratio of the total amount of the inorganic particles to the total amount of the inorganic particles.

The embodiments described above as the embodiments of the present invention can be appropriately combined as long as they do not contradict each other. It should be noted that those skilled in the art can appropriately add, remove, or change the design of the sputtering targets of the respective embodiments, or add, omit, or change the conditions of the sputtering targets according to the embodiments, And are included in the scope of the present invention.

It is to be understood that what is obvious from the description of this specification or easily predictable by a person skilled in the art is naturally caused by the present invention even if it is different from the action and effect brought about by the aspects of the above embodiments .

100: sputtering target
101: substrate
102: target member
103: Bonding material
200, 202, 204, 300, 302, 304, 310, 312, 314:
210, 212, 214, 230, 232: organic substance segregation region
220: Peak

Claims (11)

A target member in which the existence ratio of the organic material on the surface per unit area is 15.8% or less,
And a substrate bonded to the target member via a bonding material. The method according to claim 1,
Wherein the organic material comprises silicon. The method according to claim 1,
Wherein the target member and the substrate are cylindrical. The method of claim 3,
Wherein the target member is made of indium tin oxide (ITO). The method of claim 3,
Wherein the target member is made of IGZO (Indium Gallium Zinc Oxide). The method of claim 3,
Wherein the target member is made of IZO (Indium Zinc Oxide). The method according to claim 1,
Wherein a surface roughness (Ra) of the target member is less than 0.5 占 퐉. A target member whose surface is covered with a film-shaped resin is bonded to the base material through the bonding material,
Peeling the film-shaped resin from the target member,
Wherein the target member is ground on the surface of the target member such that the ratio of the organic material contained in the film-like resin per unit area is 15.8% or less. 9. The method of claim 8,
Wherein the grinding is performed by grinding the target member at least 0.15 mm from the surface. 9. The method of claim 8,
Wherein the organic material comprises silicon. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 9. The method of claim 8,
Wherein the grinding is performed so that the surface roughness (Ra) of the target member is less than 0.5 占 퐉.

Images