CN110100042B - Gas flow sputtering device and method for manufacturing sputtering target material - Google Patents

Abstract

The invention provides a gas flow sputtering apparatus suitable for manufacturing sputtering target raw material with high sputtering rate stably for a long time. The gas flow sputtering device is provided with: a pair of flat plate targets disposed in the sputtering chamber with a gap therebetween such that sputtering surfaces thereof face each other; a pair of cooling devices for cooling each of the plate targets; and a conductive fixing member for fixing the respective flat plate targets to the cooling device, wherein the pair of flat plate targets have mounting portions extending from respective side surfaces thereof, the pair of flat plate targets are fixed to the cooling device in a positional relationship in which the mounting portions are sandwiched between the fixing member and the cooling device, respectively, and the fixing member is covered with an insulating shielding member which does not contact the pair of flat plate targets.

Description

Gas flow sputtering device and method for manufacturing sputtering target material

Technical Field

The present invention relates to a gas flow sputtering apparatus and a method for producing a material for a sputtering target.

Background

In the field of magnetic recording represented by hard disk drives, as a material of a magnetic thin film responsible for recording, a material based on Co, Fe, or Ni, which is a ferromagnetic metal, is used. For example, a ferromagnetic alloy of Co-Cr system or Co-Cr-Pt system containing Co as a main component is used for a recording layer of a hard disk adopting an in-plane magnetic recording system. In the recording layer of a hard disk using a perpendicular magnetic recording system which has been put into practical use in recent years, a composite material in which nonmagnetic particles such as oxide and carbon are dispersed in a Co — Cr — Pt ferromagnetic alloy containing Co as a main component is often used.

In view of high productivity, a sputtering target having the above-described composition is often sputtered to produce a magnetic thin film for a magnetic recording medium such as a hard disk. In the non-magnetic material particle-dispersed sputtering target, the non-magnetic particles contained therein cause abnormal discharge during sputtering, and the abnormal discharge causes generation of fine particles. In recent years, with the increase in storage capacity of hard disk drives, the necessity of reducing particles from sputtering targets when manufacturing hard disk media has increased.

Sputtering targets are generally manufactured by a powder sintering method. It is known that the miniaturization of nonmagnetic particles in a sputtering target is very effective for reducing fine particles. For this reason, it is an effective method to mechanically crush and mix various raw material powders using a powerful ball mill or the like. However, in the conventional mechanical pulverization mixing method, there is a physical limit to the refinement of the structure, and it is difficult to completely eliminate the generation of particles.

Therefore, No. 2013/136962 of the japanese patent No. proposes to refine the oxide by PVD or CVD without using conventional mechanical powder crushed mixing. Specifically, a method is disclosed in which a magnetic material is formed on a substrate by PVD or CVD, the formed magnetic material is removed from the substrate, and the removed magnetic material is pulverized and used as a raw material. This document discloses that the average particle size of the oxide in the sputtering target can be reduced to 400nm or less by this technique. In the examples of this document, the film formation of the target material using the DC magnetron sputtering apparatus is disclosed.

Meanwhile, as a sputtering method, a gas flow sputtering method is also known (for example, Japanese patent application laid-open Nos. 2006-130378, 2007-186771, 2008-1957). The gas sputtering method is a method in which sputtering is performed under a relatively high pressure, and sputtering particles are transported to a target substrate for film formation by a forced flow of gas and deposited. Since this gas-flow sputtering method does not require high-vacuum evacuation, film formation can be performed by mechanical pump evacuation without using a large evacuation device such as a conventional general sputtering method, and this method can be carried out with inexpensive equipment. Furthermore, the gas flow sputtering method can realize high-speed film formation 10 to 1000 times as high as that of the normal sputtering method. Therefore, the gas flow sputtering method can reduce the equipment cost, shorten the film forming time and reduce the film forming cost.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2013/136962

Patent document 2: japanese patent laid-open publication No. 2006-130378

Patent document 3: japanese patent laid-open No. 2007-186771

Patent document 4: japanese patent laid-open No. 2008-1957

Disclosure of Invention

Technical problem to be solved by the invention

The invention disclosed in international publication No. 2013/136962 is effective for refining the structure of a nonmagnetic-material-particle-dispersed sputtering target, but requires a step of forming a film on a substrate by PVD or CVD in order to produce a raw material for the sputtering target. For this purpose, when film formation is performed using a high-performance apparatus such as a DC magnetron sputtering apparatus, there is a problem that the production cost of the sputtering target increases and the productivity is low. In this respect, since the gas sputtering method enables rapid film formation and requires low equipment cost, it is considered that the use of a material for producing a sputtering target by the gas sputtering method is advantageous.

However, attempts to produce a raw material for a sputtering target by the gas flow sputtering method have not been studied. Patent documents 2 to 4 are limited to the production of a catalyst layer of an electrode for a polymer electrolyte fuel cell, a semiconductor electrode layer for a dye-sensitized solar cell, a photocatalyst film, an antireflection film, an electrochromic element, and a transparent conductive film by a gas flow sputtering method. Therefore, there has not been a conventional art in which an apparatus is improved from the viewpoint of industrially producing a raw material for a sputtering target. In particular, since a large amount of raw material is required to be used as a raw material for a sputtering target, continuous sputtering needs to be stably performed for a long time, and there is still room for improvement in the apparatus configuration and the production method of the raw material for producing the sputtering target.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas flow sputtering apparatus suitable for producing a sputtering target material with a high sputtering rate stably for a long period of time. In addition, another technical problem to be solved by the present invention is to provide a target for gas flow sputtering. Further, another object of the present invention is to provide a method for producing a sputtering target material using the gas flow sputtering apparatus.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above-mentioned problems, and as a result, have found that the uniformity of the film thickness and the surface properties of a sputtered film formed by a gas flow sputtering apparatus are hardly problematic for the purpose of producing a raw material for a sputtering target. Therefore, in this object, it is more important to reduce abnormal discharge at the time of high sputtering rate than to improve the quality of the sputtered film. From such a viewpoint, the present inventors have found that a gas flow sputtering apparatus using a flat plate opposed type target and having the following structure is effective.

In one aspect of the present invention, a gas flow sputtering apparatus includes:

a sputtering chamber, the interior of which can be evacuated; a pair of flat plate targets disposed in the sputtering chamber with a gap therebetween such that sputtering surfaces thereof face each other; a pair of cooling devices for cooling each of the plate targets; a conductive fixing member for fixing each flat target to the cooling device; one or more gas discharge ports for supplying a sputtering gas between the pair of flat plate targets; a member for depositing sputtering particles, which is disposed so as to face the gas discharge port and so as to be located on the opposite side of the gas discharge port with a space between the pair of flat plate targets interposed therebetween,

the pair of flat plate targets have mounting portions extending from respective side surfaces, and are fixed to the cooling device in a positional relationship in which the mounting portions are sandwiched between the fixing member and the cooling device,

the fixing member is covered with an insulating shielding member that does not contact the pair of flat targets.

In one embodiment of the gas flow sputtering apparatus according to the present invention, the pair of flat plate targets has conductivity.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the pair of flat plate targets is fixed by the fixing member in a state where a surface opposite to a sputtering surface directly or indirectly contacts the cooling device.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the closest distance between each flat target and the insulating shielding member is adjusted to 0.1 to 5 mm.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the insulating shielding member is made of one or two or more materials selected from the group consisting of alumina, silica, zirconia, magnesia, yttria, calcia, titania, and boron nitride.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the insulating shield member has a peripheral wall that is erected around the side surfaces of the respective flat plate targets at intervals along the side surfaces.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the distance between the side surface of each flat target and the peripheral wall of the insulating shield member is 0.1 to 2 mm.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the insulating shield member is disposed so as to cover an edge portion of the sputtering surface of each flat plate target.

In another embodiment of the gas flow sputtering apparatus according to the present invention, the pair of flat plate targets is composed of a composite of a nonmagnetic material and a magnetic material.

In another aspect of the present invention, a method for producing a sputtering target material includes a step of sputtering using the gas flow sputtering apparatus according to the present invention.

In one embodiment of the method for producing a sputtering target material according to the present invention, the power density is set to 10W/cm²The sputtering is performed as described above.

In another embodiment of the method for producing a sputtering target material according to the present invention, the amount of the sputtering target material is 1cm²The flow rate of the sputtering gas is set to 1sccm/cm in the total projected area of the opposed sputtering surfaces of the pair of flat plate targets²The sputtering is performed as described above.

In another embodiment of the method for producing a sputtering target material according to the present invention, sputtering is performed with the pressure of the sputtering gas set to 10Pa or more.

In another embodiment of the method for producing a sputtering target material according to the present invention, the member on which the sputtering particles are deposited is a used sputtering target, and the method includes a step of depositing the sputtering particles on an erosion portion of the sputtering target.

In another embodiment of the method for producing a sputtering target material according to the present invention, the method includes: and a step of making the total mass of the sputtering particles deposited on the insulating shielding member larger than the mass of the sputtering particles deposited on the member on which the sputtering particles are deposited.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, since abnormal discharge is less likely to occur when a sputtering target material is produced using a gas flow sputtering apparatus, sputtering can be continuously and stably performed for a long period of time. Thus, a raw material for a sputtering target, particularly a raw material for a non-magnetic material particle-dispersed sputtering target having a finer structure can be produced with higher production efficiency and at lower cost than in the conventional art.

Drawings

Fig. 1 is a schematic diagram showing an example of a basic structure of the inside of a gas flow sputtering apparatus according to the present invention.

Fig. 2-1 is a schematic diagram showing an example of a schematic device configuration of a gas flow sputtering apparatus according to the present invention.

Fig. 2-2 is a schematic diagram showing another example of a schematic apparatus configuration of the gas flow sputtering apparatus according to the present invention.

Fig. 2 to 3 are schematic diagrams showing still another example of the schematic device configuration of the gas flow sputtering apparatus according to the present invention.

Fig. 3 is a schematic diagram showing a first example of a cross-sectional structure around the gas flow sputtering target and the fixing member according to the present invention (without using a backing plate).

Fig. 4 is a schematic diagram showing a second example of a cross-sectional structure around the gas flow sputtering target and the fixing member according to the present invention (without using a backing plate).

Fig. 5 is a schematic view showing a third example of the cross-sectional structure around the gas flow sputtering target and the fixing member according to the present invention (without using a backing plate).

Fig. 6 is a schematic view showing a fourth example of the cross-sectional structure around the gas flow sputtering target and the fixing member according to the present invention (without using a backing plate).

Fig. 7 is a schematic diagram (using a backing plate) showing a fifth example of a cross-sectional structure around the gas flow sputtering target and the fixing member according to the present invention.

Fig. 8 shows an example of arrangement of the flat target and the insulating shielding member in a plan view when the flat target according to the present invention is fixed in the gas flow sputtering apparatus.

Fig. 9 is a schematic diagram showing a configuration example of a sputtering gas discharge unit having a plurality of gas discharge ports.

Detailed Description

Hereinafter, various embodiments of a gas flow sputtering apparatus according to the present invention will be described in detail with reference to the drawings. Fig. 1 shows an example of a basic configuration of the inside of a gas flow sputtering apparatus according to the present invention, and fig. 2-1 to 2-3 show a schematic apparatus configuration example of the gas flow sputtering apparatus according to the present invention. In a sputtering chamber 11 in which the inside can be made vacuum (less than atmospheric pressure), sputtering surfaces of a pair of flat plate targets 10a and 10b are arranged so as to face each other with a predetermined gap therebetween. In order to increase the plasma density uniformly on the target surface and effectively increase the etching rate without any unexpected problem, it is preferable that the pair of flat plate targets 10a and 10b are arranged so that the sputtering surfaces thereof are parallel to each other in a state before the start of sputtering. However, sputtering can be performed with the sputtering surfaces being inclined so as not to be parallel to each other. A negative voltage is applied to each of the targets 10a and 10b, and plasma of sputtering gas 17 such as Ar is generated in the space 12 between the pair of flat plate targets 10a and 10b, and sputtering particles 13 are generated by causing the plasma to collide with each target.

Exemplary potentials of the respective devices at the time of sputtering are divided and shown in fig. 2-1 to 2-3. The pair of flat plate targets 10a and 10b need to be brought into a cathode potential during sputtering, and the potential at the other portion is not particularly limited as long as the sputtering apparatus can be operated safely. In view of safety, the outer wall of the sputtering chamber 11 is generally set to the anode potential. In general, in the case where insulation of a portion other than a space between the anode potential portion and the cathode potential portion is required, it is effective to use an insulating member.

The power supply of the gas flow sputtering apparatus may be either a dc power supply or an ac power supply, but the dc power supply 15 is preferable because the cost of the power supply apparatus is low or the sputtering rate per unit time is high. The generated sputtering particles 13 flow in from the sputtering gas discharge port 14, are carried by the forced flow of the sputtering gas 17 flowing into the space 12 between the pair of flat plate targets 10a, 10b in the direction of the arrow, and are deposited on the surface of a member 16 (typically, a film formation target substrate) on which the sputtering particles 13 are deposited, and the member 16 on which the sputtering particles 13 are deposited is provided so as to face the sputtering gas discharge port 14 outside the space 12 (the space surrounded by the broken line in fig. 2-1 to 2-3) between the pair of flat plate targets 10a, 10 b. In this specification, the space between the pair of flat plate targets means a portion where two spaces overlap each other in a space surrounded by a pattern formed by extending the profile of the sputtering surface of one flat plate target toward the side close to the other flat plate target in the normal direction of the sputtering surface and in a space surrounded by a pattern formed by extending the profile of the sputtering surface of the other flat plate target toward the side close to the one flat plate target in the normal direction of the sputtering surface. In the present specification, the term "the member on which the sputtering particles are deposited faces the sputtering gas discharge ports" means that a straight line extending from at least one of the sputtering gas discharge ports in the gas discharge direction intersects with the surface of the member on which the sputtering particles are deposited. The member 16 on which the sputtering particles 13 are deposited can be supported by a support 18. The holder 18 is provided on the opposite side of the sputtering gas discharge port 14 with the space 12 sandwiched between the pair of flat plate targets 10a, 10 b. After that, the sputtering gas 17 is discharged from the exhaust port 20. The exhaust port 20 can be provided, for example, at the back (in other words, inside) of the holder 18. By providing the exhaust port 20 behind the pedestal 18, the sputtering particles 13 associated with the sputtering gas 17 can efficiently strike the member 16.

In the gas flow sputtering method, since the power density and the gas flow velocity can be increased as compared with the usual sputtering method, high-speed film formation can be performed. However, if the power density is increased to perform high-speed film formation, abnormal discharge is likely to occur. This tendency is remarkable particularly when the target is made of a material containing an insulating material such as an oxide. If abnormal discharge occurs during sputtering, elements near the place where the abnormal discharge occurs are damaged, the maintenance frequency increases, and the sputtering operation must be stopped. To avoid abnormal discharge, the interval between the pair of flat plate targets 10a, 10b is shortened (S)₁) Is very effective. Specifically, the distance between the pair of flat plate targets 10a and 10b before the start of sputtering is preferably 100mm or less, more preferably 50mm or less, still more preferably 45mm or less, and further preferably 40mm or less. On the other hand, if the distance between the pair of flat plate targets 10a and 10b is excessively shortened (S)₁) The amount of gas transporting the sputtering particles 13 becomes small, and the sputtering particles 13 adhere to the target surface again, so that it is difficult to efficiently deposit the sputtering particles 13 on the member 16. Shortening the interval (S) between the pair of flat plate targets 10a, 10b₁) In this case, a method of increasing the flow rate of the sputtering gas passing between the two so that the sputtering particles 13 do not adhere to the target surface facing each other may be considered. From this viewpoint, a pair of sputtering targets before the start of sputteringThe interval between the flat plate targets 10a, 10b is preferably 10mm or more, and more preferably 15mm or more.

As the sputtering time becomes longer, the thickness of the target becomes thinner due to erosion. Therefore, if the interval between the pair of flat plate targets 10a and 10b is not complemented, the interval gradually increases with the change in sputtering time, the voltage applied to the targets gradually increases, and the risk of abnormal discharge increases. However, if the interval between the pair of flat plate targets 10a, 10b is maintained within a certain range regardless of the thickness of the targets, for example, within an appropriate range of the interval between the pair of flat plate targets 10a, 10b described above, the risk of occurrence of abnormal discharge is not increased. Therefore, in the embodiment of the gas flow sputtering apparatus according to the present invention, the gap adjusting mechanism 19 is provided, so that when the pair of flat plate targets 10a and 10b is eroded by sputtering, the gap between the pair of flat plate targets can be maintained within a certain range or can be set to a gap required at the start of sputtering. In fig. 2, a pair of flat plate targets 10a and 10b are fixed to a cooling device 50, respectively, to form integral structural elements, and each integral structural element is movable by a corresponding gap adjustment mechanism 19.

The interval adjustment mechanism 19 is not particularly limited, and any known mechanism can be used, and examples thereof include linear motion mechanisms such as a cylinder linear motion mechanism and a ball screw linear motion mechanism. The driving method is not particularly limited, and motor driving, hydraulic driving, pneumatic driving, and the like can be mentioned. From the viewpoint of being able to precisely adjust the position, a motor-driven linear motion mechanism is preferable. The interval between the pair of flat plate targets 10a, 10b may be automatically changed to a desired set value or may be manually changed. In addition, the change in the gap between the pair of flat plate targets 10a and 10b may be monitored during sputtering, and feedback control may be performed to maintain the gap set initially during sputtering. The feedback control may be manual or automatic. As a method of measuring the change in the distance between the pair of flat targets 10a and 10b, for example, a method of providing a weight sensor so as to be able to measure the weight of each of the flat targets 10a and 10b and calculating an average decrease in the target thickness (that is, an average increase in the distance between the targets) from the target weight decrease amount, the target density, and the projection area of the sputtering surface is included. In order to automatically calculate the average reduction amount of the target thickness, a computer may be mounted on the apparatus, or the calculation result may be displayed on a display attached to the apparatus. In addition, the following methods are also conceivable: the relationship between the discharge time and the integrated power and the average reduction amount of the target thickness is determined in advance for the flat targets 10a and 10b as sputtering targets, and based on this, the average reduction amount of the target thickness is calculated from at least the discharge time and the integrated power.

Then, the interval adjustment mechanism 19 is manually or automatically operated to reduce the average interval between the two targets by an amount corresponding to the sum of the average reduction amounts of the thicknesses of the targets 10a and 10b, so that the interval between the pair of flat plate targets 10a and 10b can be maintained within a certain range from the start to the end of sputtering. Since the voltage can be changed by 100V or more even if the distance between the pair of flat plate targets 10a and 10b is changed by about 1cm, the change in the average distance between the pair of flat plate targets 10a and 10b from the start of sputtering to the end of sputtering is preferably 5mm or less, more preferably 4mm or less, still more preferably 3mm or less, still more preferably 2mm or less, and further more preferably 1mm or less, from the viewpoint of continuing stable sputtering.

As shown in fig. 2-2, the gap adjusting mechanism 19 may be provided in the sputtering chamber 11, but when provided in the sputtering chamber 11, the gap adjusting mechanism 19 needs to be resistant to vacuum, and is exposed to plasma in the sputtering chamber 11, and there is a possibility that the operation may be disturbed due to particle deposition, and therefore measures against this need to be taken. Further, when oil such as lubricating oil is used for the interval adjustment mechanism 19, evaporation may occur in a vacuum atmosphere, and this may be required to be dealt with. Therefore, as shown in fig. 2 to 3, it is preferable that at least a part of the interval adjusting mechanism 19 is provided outside the sputtering chamber 11 (in fig. 2 to 3, a linear motion member such as a screw shaft in the case of a ball screw linear motion mechanism is provided inside the chamber 11, but a power source of a motor or the like is provided outside the chamber 11), and as shown in fig. 2 to 1, it is more preferable that the interval adjusting mechanism 19 is provided entirely outside the sputtering chamber 11. When the gap adjustment mechanism 19 is provided outside the sputtering chamber 11, it is preferable that a boundary between a part of the inside and the outside of the sputtering chamber 11 is defined by the extensible member 52, and the extensible member 52 is disposed so as to be extensible and contractible in accordance with the operation of the gap adjustment mechanism 19 and has an atmospheric barrier performance. By the expansion/contraction member 52 expanding and contracting in accordance with the operation of the gap adjustment mechanism 19, even if the movable portion of the gap adjustment mechanism 19 moves during sputtering, the inside of the sputtering chamber 11 can be kept vacuum (less than atmospheric pressure) while being isolated from the atmosphere. The expansion member 52 is not particularly limited as long as it can perform the above-described function, and examples thereof include a bellows. As a material of the stretchable member, stainless steel, titanium, high nickel alloy (Hastelloy), aluminum, or the like is preferably used from the viewpoint of durability against repeated stretching in a state where a force of the magnitude of atmospheric pressure is applied to the inside and outside.

In order to efficiently deposit the sputtering particles 13 on the member 16 on which the sputtering particles 13 are deposited, the direction of the forced flow of the sputtering gas 17 is preferably perpendicular to the surface of the member 16 on which the sputtering particles 13 are deposited.

In order to prevent the growth of the sputtering particles adhering to the member 16 (typically, a substrate to be film-formed) on which the sputtering particles 13 are deposited, the member 16 is preferably cooled. When cooling, the material of the member 16 on which the sputtered particles 13 are deposited is not particularly limited, and plastic, glass, metal, ceramic, or the like can be used. When cooling is not performed, a heat-resistant material such as glass, metal, or ceramic is preferable as the material of the member 16 on which the sputtering particles 13 are deposited. This is because there is an influence of flowing the gas toward the component 16 side in the gas flow sputtering, and the plasma may reach the vicinity of the component 16. Among them, in order to easily recover the deposited sputtering particles, the member 16 is preferably made of one or more materials selected from the group consisting of alumina, silica, zirconia, magnesia, yttria, calcium oxide, titanium oxide, boron nitride, aluminum, iron, copper, titanium, niobium, tantalum, tungsten, molybdenum, cobalt, chromium, nickel, and graphite, and particularly, a material which does not react with the sputtering particles and has poor wettability is more preferable. In addition, it is preferable to select the raw material in consideration of contamination according to the end use. Further, a method of directly depositing the same material as the sputtering particles 13 as the member 16 can also be employed. In this case, a method of depositing sputtering particles on an erosion portion of a used sputtering target to return to their original shape and regenerating the sputtering target is also conceivable. The thus regenerated sputtering target can be pressurized and/or heated as necessary.

The shape of the member 16 on which the sputtering particles 13 are deposited is not particularly limited, and generally, a plate shape or a film shape can be used. In the gas flow sputtering apparatus, the member 16 on which the sputtering particles 13 are deposited can be supported on the support 18 by means of a jig, a fastening screw, an adhesive, a tape, or the like. Further, the member 16 may have a box-like container shape to collect more sputtering particles.

As the sputtering gas 17, two or more of the following gases can be used alone or in combination: he. Rare gas such as Ar, Ne, Kr, Xe, N₂、O₂And the like. Among them, Ar is preferable in view of cost, and Kr and Xe are preferable in view of efficiently moving the sputtering particles. In addition, N can be used as needed in addition to the inert gas₂And/or O₂. By using N₂And/or O₂Since reactive sputtering of nitrides and oxides can be performed using a metal as a target, the following advantages cannot be obtained by the conventional production method: the raw material and the compound in a non-equilibrium state can be made into a high-purity powdery raw material.

In the gas flow sputtering apparatus, the flow rate of the sputtering gas can be made much larger than that of the DC magnetron sputtering apparatus. By increasing the flow rate of the sputtering gas, the sputtering particles can be deposited on the member on which the sputtering particles are deposited at a high speed. In one embodiment of the gas flow sputtering apparatus according to the present invention, the flow rate of the sputtering gas may be 1sccm/cm²The above. The flow rate of the sputtering gas is preferably 2sccm/cm²The concentration is more preferably 5sccm/cm²The above. On the other hand, when the flow rate of the sputtering gas is too large, the pressure in the chamber increases due to the limitation of the capacity of the exhaust pump, and therefore, it is preferable to be 200sccm/cm²Hereinafter, more preferably 100sccm/cm²Hereinafter, it is more preferably still 50sccm/cm²The following. sccm means at 0 ℃ and 1Ccm (cm) at atm³In/min). Here, the flow rate is a value obtained by dividing the flow rate of the sputtering gas by the total projected area of the facing sputtering surfaces of the pair of flat plate targets 10a and 10 b. For example, the flow rate of the sputtering gas is 5000sccm, and the length of each of the two targets facing each other is 100cm, 10cm in the vertical direction and 10cm in the horizontal direction²In the case of the sputtering surface of projected area (2), the flow rate is 5000 sccm/(100X 2) cm²＝25sccm/cm²。

In addition, in the gas flow sputtering apparatus, the pressure of the sputtering gas can be made much larger than the flow rate of the DC magnetron sputtering apparatus. By increasing the gas pressure, the advantage of reducing the discharge voltage can be obtained. In one embodiment of the gas flow sputtering apparatus according to the present invention, the absolute pressure of the sputtering gas may be 10Pa or more. The absolute pressure of the sputtering gas is preferably 20Pa or more, more preferably 30Pa or more, and still more preferably 40Pa or more. On the other hand, when the absolute pressure of the sputtering gas is too high, abnormal discharge tends to increase, and therefore, 200Pa or less is preferable, 150Pa or less is more preferable, and 100Pa or less is still more preferable. Here, the absolute pressure of the sputtering gas is a pressure in a space between the pair of targets facing each other, and the pressure in the sputtering chamber 11 is generally highly uniform, so that if the pressure is a space in the sputtering chamber 11, substantially the same value can be obtained even when the pressure is measured at other positions such as near the sputtering gas discharge port 14 and near the exhaust port 20.

From the viewpoint of improving the productivity of producing a sputtered film by the gas flow sputtering apparatus, the power density is preferably high. However, when the power density is increased, there is a problem that abnormal discharge is likely to occur. In one embodiment of the gas-flow sputtering apparatus according to the present invention, since the gap adjustment mechanism for maintaining the gap between the pair of flat plate targets within a predetermined range is provided, the occurrence of abnormal discharge can be reduced, and therefore, the apparatus can be stably gas-flow sputtered for a long period of time even if the power density is increased. Illustratively, the gas flow sputtering device according to the present invention can be used at a flow rate of 10W/cm²The power density is preferably 20W/cm²The power density is preferably 30W/cm²The above power density operation. Although the power density is not particularly setHowever, since the discharge voltage rises when an excessively high power density is set, it is generally preferable to operate at a discharge voltage of 900V or less as much as possible in order to reduce the occurrence of abnormal discharge by adjusting the power density so that the discharge voltage is 1000V or less. Here, the power density is the total power ÷ total area of the sputtering surfaces of the opposed targets (here, the sum of the projected areas of the opposed sputtering surfaces of the pair of flat plate targets). For example, in the case of a pair of flat plate targets having a sputtering surface of 10cm in the vertical direction × 15cm in the horizontal direction, the total projected area of the sputtering surfaces of the targets is 150cm²×2＝300cm²。

The material of the target is not particularly limited, and a conductive material such as a metal (including an alloy) can be suitably used. Further, an insulating material may be used, and a conductive material and an insulating material may be used together. As a material of the target, a ferromagnetic material containing one or more metal elements selected from the group consisting of Co, Fe, Ni, and Gd can be used. Non-magnetic materials such as non-magnetic metals (aluminum, copper, ruthenium, zinc, titanium, manganese, scandium, zirconium, hafnium, chromium alloys, etc.), oxides, carbides, nitrides, carbonitrides, and carbon can also be used, and ferromagnetic materials and non-magnetic materials can also be used together. As a sputtering target which can remarkably achieve the effect of reducing abnormal discharge by the gas flow sputtering apparatus according to the present invention, there are a sputtering target composed of a composite of a conductive material and an insulating material, and a sputtering target composed of a composite of a nonmagnetic material and a magnetic material. Since such a composite contains an insulating material or a nonmagnetic material, abnormal discharge is particularly likely to occur during sputtering, and therefore the advantage of using the gas flow sputtering apparatus according to the present invention is remarkable. Examples of the combination of the materials constituting the composite of the ferromagnetic material and the nonmagnetic material include a Cr-Co alloy magnetic material containing a nonmagnetic material, a Cr-Pt-Co alloy magnetic material containing a nonmagnetic material, a Pt-Fe alloy magnetic material containing a nonmagnetic material, an Fe-Ni alloy magnetic material containing a nonmagnetic material, an Fe-Co alloy magnetic material containing a nonmagnetic material, an Fe-Ni-Co alloy magnetic material containing a nonmagnetic material, and the like. In a typical embodiment, a nonmagnetic material particle-dispersed sputtering target in which nonmagnetic material particles are dispersed in a ferromagnetic material is provided as a sputtering target composed of a composite of a nonmagnetic material and a magnetic material.

The present invention relates to a gas flow sputtering apparatus for producing a sputtering target material without forming a high-quality sputtering film. In this case, it is preferable that the sputtering target used in the gas flow sputtering apparatus according to the present invention can be produced at low cost. For example, although a sputtering target having a high relative density is often used to form a uniform sputtering film, the sputtering target used in the gas flow sputtering apparatus according to the present invention is not required to have such a high relative density. Therefore, in one embodiment, the relative density of the sputtering target for gas flow sputtering according to the present invention may be 90% or less, 80% or less, and 70% or less. However, when the relative density is too low, it is difficult to secure sufficient strength required for use as a sputtering target. In addition, the impedance value of the target itself increases, and conductivity cannot be obtained in some cases. Therefore, the sputtering target for gas flow sputtering according to the present invention has a relative density of preferably 40% or more, more preferably 50% or more, and still more preferably 60% or more. Such a target with a low relative density can be produced by merely agglomerating raw material powder into an integrated mass by low-temperature sintering or cold forming, and therefore can be produced at low cost. In addition, materials that have been difficult to form into a target shape, such as materials that are difficult to sinter, materials with a low melting point, materials with a large difference in melting point, and materials that require high purity, can also be used. The relative density is a value expressed by a percentage of a measured density divided by a theoretical density. The measured density is calculated from the weight and the volume determined from the dimensions and shape. The theoretical density is a value theoretically determined from the composition of the material constituting the sputtering target.

From the viewpoint of improving the productivity of producing a sputtered film by a gas flow sputtering apparatus, the total projected area of the facing sputtering surfaces of the pair of flat plate targets is preferably 300cm²Above, more preferably 500cm²Above, still more preferably 1000cm²The above. The total projected area has no particular upper limit, but is generally 10000cm in terms of practicality²Below, typically 8000cm²Hereinafter, more typically 6000cm²The following. For example, when the sputtering surface of each flat plate target has a rectangular shape of 10cm × 20cm, the total projected area of the facing sputtering surfaces of the pair of flat plate targets can be calculated to be 10cm × 20cm × 2 to 400cm²。

The shape of the sputtering surface of the flat plate target facing each other is not particularly limited, and examples thereof include a square, a rectangle, a polygon, an ellipse, and a circle. Among them, a rectangular shape is preferable for efficiently collecting the sputtered particles. Further, the length of the facing surface of the flat target in the direction perpendicular to the flow direction of the sputtering gas (Y in fig. 1) is preferably longer than the length thereof in the direction parallel to the flow direction of the sputtering gas (X in fig. 1) because sputtering efficiency can be improved. Specifically, Y/X ≧ 1 is preferred, Y/X ≧ 1.2 is more preferred, and Y/X ≧ 1.5 is still more preferred. However, when Y/X is too large, it is difficult to handle the target, so Y/X ≦ 20 is preferable, Y/X ≦ 15 is more preferable, and Y/X ≦ 10 is still more preferable.

The thickness of each of the pair of flat plate targets is not particularly limited, and may be set as appropriate depending on the film formation use time or the like, but is preferably thick in view of extending the time during which continuous sputtering is possible. Therefore, the thickness of each flat target is preferably 3mm or more, more preferably 5mm or more, and still more preferably 10mm or more. However, since there is a technical limit to increasing the thickness, it is generally 30mm or less, typically 20mm or less, and more typically 15mm or less. In order to perform continuous sputtering for a long time, a plurality of flat plate targets may be stacked and used. By adopting such a configuration, it is not necessary to replace the sputtering target every time it is consumed.

The flat plate targets 10a and 10b can be mounted on the cooling device 50 in the gas flow sputtering device after being fixed to the backing plate 47 as necessary. In the present invention, when the backing plate 47 is used, an assembly of the flat target and the backing plate is referred to as a "flat target", and the "flat target" as the assembly is fixed to the cooling apparatus 50 in the gas flow sputtering apparatus. Examples of the material of the back plate include copper, a copper alloy, aluminum, an aluminum alloy, titanium, a titanium alloy, iron, an iron alloy, molybdenum, a molybdenum alloy, cobalt, and a cobalt alloy.

The flat plate targets 10a, 10b can be fixed on the cooling device 50 using the fixing member 45 described below without using a backing plate. In addition, even when a backing plate is not used, the bottom portions of the flat targets 10a and 10b can be formed into a backing plate shape. In other words, the flat plate targets 10a and 10b can be integrated with the backing plate using the same material.

The method of fixing the flat plate targets 10a and 10b to the backing plate 47 is not particularly limited, and examples thereof include a method of bonding with an adhesive and a method of diffusion bonding with the backing plate 47. In the method of bonding by an adhesive, since setting the power density high as described above causes the bonded portion to have a high temperature as well, it is preferable to use a conductive adhesive having heat resistance. The conductive adhesive having heat resistance particularly preferably has a melting point of 200 ℃ or higher.

The sputtering gas 17 flows into the sputtering chamber 11 from the sputtering gas discharge port 14, and flows in the direction of the arrow through the space portion 12 between the pair of flat plate targets 10a, 10 b. The number of the sputtering gas discharge ports 14 may be one or two or more. However, in order to reduce variations in the flow rate of the sputtering gas 17 flowing into the pair of flat plate targets 10a and 10b over the entire length of the side surfaces on the side where the sputtering gas 17 flows (in other words, the length in the longitudinal direction of the slit that becomes the entrance of the space portion 12) (Y in fig. 1), or in order to be able to adjust the flow rate of the sputtering gas 17, it is preferable to provide two or more sputtering gas discharge ports 14 along the longitudinal direction of the slit. In the case where two or more sputtering gas discharge ports 14 are provided, a sputtering gas discharge means 22 can be used for simplifying the piping structure, and the sputtering gas discharge means 22 can branch the sputtering gas supplied from one or two or more gas supply pipes and flow out from a larger number of discharge ports than the number of gas supply pipes. One or more than two sputtering gas exhaust units 22 can be provided.

The structure of such a gas discharge unit 22 is shown in fig. 9, for example. The gas discharge unit 22 includes: a gas introduction pipe 28 having an inlet 24 for introducing the sputtering gas 17 from a gas supply pipe (not shown); the tubular member 26 is connected to a gas introduction pipe 28, and a plurality of sputtering gas discharge ports 14 are aligned in a row on a side surface thereof. The sputtering gas 17 flowing in from the inlet 24 of the gas exhaust unit 22 passes through the gas introduction pipe 28 and the inside of the tubular member 26 in this order, and then flows out from the plurality of sputtering gas exhaust ports 14. The sputtering gas discharge port 14 is preferably arranged along the longitudinal direction of the slit that becomes the entrance of the space portion 12.

The flow rate of the sputtering gas 17 discharged from each of the sputtering gas discharge ports 14 may be controlled by a flow rate control mechanism such as a mass flow controller or a flow rate control valve (butterfly valve, needle valve, gate valve, ball valve), or the like, or such a flow rate control mechanism may be provided in accordance with the number of gas supply pipes connected to the gas discharge unit 22, and the flow rate of the sputtering gas 17 discharged from the plurality of discharge ports 14 may be controlled uniformly.

The relative positional relationship between the sputtering gas discharge port 14 and the pair of flat plate targets 10a and 10b may be fixed, or a position adjustment mechanism capable of performing relative adjustment as needed may be provided. Examples of the position adjustment mechanism include the following: the gas introduction pipe 28 is fixed to the wall of the sputtering chamber 11 by using a sealing material 29 such as a ferrule, an O-ring, a packing, or a gasket, and the distance between the gas introduction pipe 28 and the wall is adjusted by loosening the sealing material 29 (see fig. 2-1 to 2-3). In this case, from the viewpoint of operability, the sealing material 29 is preferably provided outside the sputtering chamber 11.

Fig. 3 is a schematic diagram showing an example of a cross-sectional structure around the flat plate targets 10a and 10b for gas flow sputtering and the fixing member 45 according to the present invention, without using the backing plate 47. When the target has a mounting portion 102 extending from the side surface 101, the target is fixed to the cooling device 50 in a positional relationship in which the mounting portion 102 is sandwiched between the conductive fixing member 45 and the cooling device 50 via the diaphragm (indirect cooling plate) 46. The target may be fixed to the cooling device 50 without interposing the diaphragm 46 therebetween in a positional relationship in which the mounting portion 102 is directly sandwiched between the conductive fixing member 45 and the cooling device 50. The cooling efficiency is higher when the diaphragm 46 is not present, but in this case, when the inside of the sputtering chamber 11 is evacuated, the cooling water 48 needs to be discarded in order to prevent the cooling water 48 from leaking from the cooling device 50, and therefore, the diaphragm 46 is preferably provided from the viewpoint of maintainability.

The conductive fixing member 45 is used because the insulating material cannot obtain sufficient strength. The mounting portion 102 can be integrally formed with the flat target body portion. The region where the mounting portions 102 are provided is not particularly limited as long as the flat plate targets 10a, 10b can be fixed to the cooling device 50, and the mounting portions 102 may be provided continuously around the side surfaces 101 of the flat plate targets 10a, 10b, or the number of mounting portions 102 necessary for fixing the flat plate targets 10a, 10b to the cooling device 50 may be provided intermittently at a plurality of positions. From the viewpoint of workability of the flat plate targets 10a, 10b and strength of the mounting portion, it is preferable to provide the mounting portion 102 continuously around the side surface 101 of the flat plate targets 10a, 10 b.

In addition to performing stable discharge, it is preferable that the conductive fixing member 45 sandwiching the mounting portion 102 does not protrude upward beyond the upper surface (sputtering surface) 103 of the flat plate targets 10a and 10 b. Therefore, the upper surface of the mounting portion 102 extending from the side surface 101 is preferably located lower than the upper surface 103 of the flat plate targets 10a and 10 b. In this case, when the cross section of the target is observed, the upper surfaces 103 of the flat plate targets 10a and 10b and the upper surface of the mounting portion 102 form a step. On the other hand, from the viewpoint of securing the fixing strength between the flat plate targets 10a, 10b and the cooling device 50, the lower surface 104 of the mounting portion 102 extending from the side surface 101 is preferably the same height as the lower surface 106 of the flat plate targets 10a, 10 b. That is, the lower surfaces 106 of the flat targets 10a and 10b are preferably flush with the lower surface 104 of the mounting portion 102.

The material of the conductive fixing member 45 is not particularly limited, but preferably has heat resistance. As the heat-resistant conductive material, a metal is cited, and a metal having a melting point higher than that of aluminum (660.3 ℃), particularly preferably a metal having a melting point of 700 ℃ or higher, still more preferably a metal having a melting point of 800 ℃ or higher, and further preferably a metal having a melting point of 1000 ℃ or higher is particularly preferable. Carbon such as graphite can also be used. For example, a material selected from the group consisting of iron, copper, titanium, niobium, tantalum, tungsten, molybdenum, cobalt, chromium, nickel, and graphite may be used alone, or an alloy (including stainless steel) or a metal-graphite composite may be used in combination of two or more kinds. Among them, stainless steel is preferable for reasons of high strength, easy purchase, and low cost.

The shape and size of the conductive fixing member 45 are not particularly limited as long as the flat plate targets 10a and 10b can be fixed to the cooling device 50 in a positional relationship in which the mounting portion 102 is sandwiched between the conductive fixing member 45 and the cooling device 50, but for the reason of performing stable discharge, the upper surface of the conductive fixing member 45 preferably does not protrude upward beyond the upper surfaces of the flat plate targets 10a and 10b, and is more preferably located at a position lower than the upper surfaces of the flat plate targets 10a and 10 b. The conductive fixing member 45 may be formed of an integrally molded product, or may be formed by combining two or more members. For example, in the embodiment shown in fig. 3, in the case where a plurality of mounting portions 102 are provided continuously around the side surface 101 of the flat plate targets 10a, 10b, the conductive fixing member 45 can be constituted by a frame-shaped first fixing element 45a and a frame-shaped second fixing element 45b placed on the first fixing element 45a, the first fixing element 45a having a lower surface on the same plane as the lower surface 104 of the mounting portion 102, an upper surface on the same plane as the upper surface of the mounting portion 102, and an inner side surface closely attached to the side surface of the mounting portion 102; the second fixing member 45b has a lower surface flush with the upper surface of the mounting portion 102, an upper surface located lower than the upper surface 103 of the flat plate targets 10a, 10b, and an inner side surface closely attached to the side surface 101 of the flat plate targets 10a, 10 b. In this case, the first fixing element 45a and the second fixing element 45b are preferably in contact with each other continuously without steps on the outer side surfaces of the first fixing element 45a and the second fixing element 45b, for the reason that the sputtering apparatus and the shielding shape can be simplified. In a typical embodiment, the first and second fixing elements 45a and 45b can be provided in the form of rectangular frames, respectively.

The conductive fixing member 45 is preferably not sputtered. When the conductive fixing member 45 is sputtered, a desired composition of a sputtered film cannot be obtained, and the maintenance frequency of the conductive fixing member 45 is increased, which is inconvenient. Although the entire amount of sputtered particles is ideally deposited on the member 16, if the sputtering rate is increased to improve the production efficiency, many sputtered particles are scattered around the flat targets 10a and 10 b. As a result, the sputtering ions are also deposited on the conductive fixing member 45 and are likely to further diffuse to the surroundings. When the deposition range of the sputtered particles is increased, if the sputtered particles are conductive, there is a possibility that a position which should be a cathode potential and a position of an anode (ground) potential are short-circuited. Therefore, the conductive fixing member 45 is preferably covered with the insulating shielding member 49. In other words, the insulating shielding member 49 can also be said to function as a member for depositing sputtering particles.

In the embodiment shown in fig. 3, the insulating shielding member 49 includes a side plate 492 covering the outer surface of the conductive fixing member 45 and an upper surface plate 493 covering the upper surface of the conductive fixing member 45. In order to enhance the effect of preventing the conductive fixing member 45 from being sputtered, the distance L3 between the lower surface of the upper panel 493 of the insulating shield member 49 and the upper surface of the conductive fixing member 45 is preferably 10mm or less, more preferably 5mm or less, and still more preferably 2mm or less. L3 may be 0 because the lower surface of the upper panel 493 of the insulating shielding member 49 does not cause abnormal discharge even if it contacts the upper surface of the conductive fixing member 45.

The insulating shielding member 49 is preferably made of a heat-resistant material. The insulation resistance of the insulating shielding member 49 is such that the insulation breakdown voltage at the thickness of the member to be installed is preferably 1kV or more, more preferably 2kV or more, and still more preferably 10kV or more. Suitable examples of the heat-resistant material constituting the insulating shield member 49 include one or more selected from the group consisting of alumina, silica, zirconia, magnesia, yttria, calcia, titania, and boron nitride. When these materials are used, the adhered sputtered particles can be easily recovered.

In order to prevent abnormal discharge, it is preferable that the insulating shielding member 49 does not contact the targets 10a and 10b, and if the distance between the insulating shielding member 49 and the targets 10a and 10b is increased, the portion of the conductive fixing member 45 not covered with the insulating shielding member 49 becomes larger, and the effect of preventing sputtering of the conductive fixing member 45 becomes weaker. Therefore, when the pair of flat plate targets 10a and 10b are viewed in plan, the closest distance (L1) between each target 10a and 10b and the insulating shielding member 49 is preferably adjusted to 0.1mm or more, more preferably 0.3mm or more, and still more preferably 0.5mm or more. The closest distance (L1) is preferably adjusted to 5mm or less, more preferably 3mm or less, and still more preferably 1mm or less.

In the embodiment shown in fig. 3, when the flat plate targets 10a and 10b are respectively viewed in plan, a gap (L1) closest to each other is generated between each of the targets 10a and 10b and the insulating shielding member 49. In this case, a sputtering gas may enter from the gap, and the conductive fixing member 45 may be sputtered. Therefore, in order to improve the effect of preventing the conductive fixing member 45 from being sputtered, as shown in fig. 4, an insulating shielding member 49 may be disposed so as to cover the edge of the upper surface (sputtering surface) 103 of each of the flat plate targets 10a and 10 b. In this case as well, the closest distance (L1) between each target 10a, 10b and the insulating shielding member 49 is preferably adjusted to be within the above-described range.

If necessary, the insulating shield member 49 may be covered with another shield member in order to reduce the deposition of the sputtering ions on the insulating shield member 49. In this case, the shielding member is preferably heat-resistant regardless of whether it is conductive or insulating.

Note that, when the material of the shielding member 49 is changed from insulating to conductive, the discharge voltage is increased to a level that increases the discharge power, and therefore the risk of arcing between the shielding member 49 and the conductive fixing member 45 is increased, and therefore the shielding member 49 needs to have insulating properties in order to perform stable sputtering over a long period of time.

The cooling device 50 is in contact with the respective flat plate targets 10a, 10b, and can therefore be brought into a cathode potential. Therefore, in order to prevent the cooling device 50 from being sputtered, it is preferable to dispose the insulating shielding member 501 for the cooling device so as to cover the outer surface of the cooling device 50. Although the sputtering prevention effect can be obtained by covering at least a part of the outer surface of the cooling device 50 with the insulating shielding member 501, it is preferable to cover the entire outer surface. The insulating shielding member 501 can directly contact the outer surface of the cooling device 50. A suitable material for the insulating shielding member 501 for the cooling device is the one described for the insulating shielding member 49.

Fig. 7 is a schematic diagram showing an example of a cross-sectional structure of the flat targets 10a and 10b for gas sputtering according to the present invention when the backing plate 47 is used. The operation and preferred embodiment of each component element denoted by the same reference numerals are as described in fig. 3, and the description will be mainly given of the structure different from the embodiment of fig. 3, with the overlapping description omitted. The portion of the backing plate 47 of the target extends from the side 101 to form a mounting location 102. The target is fixed to the cooling device 50 in a positional relationship in which the mounting portion 102 is directly sandwiched between the conductive fixing member 45 and the cooling device 50. In the present embodiment, since the back plate 47 is present, there is no risk of leakage of cooling water when the sputtering chamber 11 is evacuated, and therefore, it is not necessary to insert the diaphragm 46.

In the present embodiment, the shape and size of the conductive fixing member 45 are not particularly limited as long as the targets 10a and 10b can be fixed to the cooling device 50 in a positional relationship in which the mounting portion 102 is sandwiched between the conductive fixing member 45 and the cooling device 50. In the embodiment shown in fig. 7, the conductive fixing member 45 is an integrally molded product, and has a frame structure having a lower surface flush with the upper surface of the mounting portion 102, an upper surface located lower than the upper surface 103 of the flat plate targets 10a and 10b, and an inner side surface closely attached to the side surface 101 of the flat plate targets 10a and 10 b. In a typical embodiment, the conductive fixing member 45 may be provided in the form of a rectangular frame.

In the embodiment of fig. 3 and 7, the insulating shielding member 49 has a peripheral wall 491 which is erected along the side surface 101 of the flat plate targets 10a and 10b and surrounds the side surface 101 with a space L1 therebetween. Since the peripheral wall 491 is present, the side surfaces of the flat plate targets 10a and 10b are hidden, and therefore, the discharge is easily stabilized. Further, an effect that the plasma conductive fixing member 45 is hardly sputtered can be expected.

The peripheral wall 491 is not essential, and as shown in fig. 5, a system in which the peripheral wall 491 is not provided can be adopted. As shown in fig. 6, the top panel 493 of the insulating shielding member 49 can be increased in thickness to increase the strength of the insulating shielding member. According to this embodiment, since the target side surface can be hidden, the same effect as the peripheral wall 491 can be expected.

The structure of the insulating shielding member 49 is not limited to the embodiment shown in fig. 3 to 7, and other embodiments may be adopted. For example, in the embodiment shown in fig. 2-2, the insulating shield member 49 does not include the side plate 492. In the embodiment shown in fig. 2-3, the fastener mounting base 502 is covered by the upper panel 493 and the side panels 492 of the insulating shield member 49.

Fig. 8 is a plan view showing an example of the arrangement relationship between the flat plate targets 10a and 10b and the insulating shielding member 49 when the rectangular flat plate targets 10a and 10b are used. In the embodiment shown in fig. 8, rectangular flat plate targets 10a and 10b are disposed around a peripheral wall 491 of a rectangular frame-shaped insulating shield member 49.

In order to maintain stable discharge, the distance L1 between the side surface 101 of the flat plate targets 10a and 10b and the peripheral wall 491 of the insulating shield member 49 is preferably 0.1mm or more, more preferably 0.2mm or more, and still more preferably 0.3mm or more. For the reason of preventing the fixing member 45 from being sputtered, the interval L1 is preferably 2mm or less, more preferably 1.5mm or less, and still more preferably 1mm or less.

As a method of fixing the flat plate targets 10a, 10b to the cooling device 50, the following method can be mentioned: one or more through holes are provided in the conductive fixing member 45, and one or more through holes are also provided in the diaphragm 46 if provided, and further, a mounting hole is provided in the cooling device 50, and a fastening member 51 such as a bolt or a screw is inserted into the through hole and the mounting hole in this order to fix (see fig. 3 to 6). One or more through holes may be provided in the mounting portion 102, and the fastener 51 (see fig. 7) may be inserted. Further, as a method of fixing the insulating shielding member 49, the following method may be mentioned: the insulating shielding member 49 is provided with a through hole, and the insulating shielding member 501 for a cooling device is also provided with a mounting hole, and a fastening member 503 such as a bolt or a screw is inserted into the through hole and the mounting hole in this order and fixed. In this case, when the fastener 503 is made of metal, in order to prevent the fastener 503 from being sputtered, it is preferable to ground the fastener 503 to be an anode potential.

From the viewpoint of durability, a metal material is more preferable for the mounting hole for the fastener 503 than an insulating material such as ceramic. Therefore, a metal fastener mounting base 502 may be provided on the outer side surface of the insulating shielding member 501 for a cooling device, and a mounting hole may be provided in the fastener mounting base 502. The fastener mounting base 502 may be directly disposed on the outer side surface of the insulating shielding member 501 so as to surround the outer side surface of the insulating shielding member 501. In the case where the fastener 503 is made of metal, in order to prevent the fastener 503 from being sputtered, it is preferable to ground the fastener 503 so that it becomes an anode potential. Further, in order to prevent the fastener mounting base 502 from being sputtered, it is preferable to ground the fastener mounting base 502 to an anode potential.

According to one embodiment of the gas flow sputtering apparatus of the present invention, the sputtering rate is set to 0.005g/h/cm²Above, preferably 0.01g/h/cm²Above, more preferably 0.02g/h/cm²Above, for example, 0.005 to 0.1g/h/cm²Continuous sputtering can be performed for 5 hours or more without abnormal discharge. However, the reference area of the sputtering rate is the total area of the sputtering surfaces of the facing targets (here, the total of the projected areas of the facing sputtering surfaces of the pair of flat plate targets). The sputtering film obtained by sputtering using the gas flow sputtering apparatus according to the present invention can be peeled from the member on which the sputtering particles are deposited, recovered, and then pulverized to be used as a sputtering target material. By sintering this raw material, a sputtering target can be produced. In particular, the present invention is useful as a method for efficiently producing a nonmagnetic material particle-dispersed sputtering target having a finer structure.

According to one embodiment of the method for producing a sputtering target material using the gas flow sputtering apparatus according to the present invention, the total mass of the sputtering particles deposited on the insulating shielding member 49 can be made larger than the mass of the sputtering particles deposited on the member 16 on which the sputtering particles are deposited. For example, the ratio of the total mass of the sputtering particles deposited on the insulating shielding member 49 to the mass of the sputtering particles deposited on the member 16 may be 2 or more, 3 or more, and 4 or more. Therefore, it is also important to collect the sputtering particles deposited on the insulating shielding member 49 and use them as a sputtering target material in order to improve productivity.

[ examples ] A method for producing a compound

While embodiments of the present invention are illustrated below, the provision of these embodiments is considered to provide a better understanding of the present invention and its advantages, and is not intended to limit the invention.

< 1. verification of Effect of Interval Regulation of Flat target >

(test example 1)

A sputtering film was formed under the following conditions by using a flat-plate target opposed-type gas flow sputtering apparatus having the structure shown in fig. 1 and 2-1 (however, the structure of mounting a sputtering target was the structure shown in fig. 3), and mounting the sputtering target according to the structure shown in fig. 3 and 8. As the interval adjusting mechanism of the pair of plate targets, a ball screw linear motion mechanism is used. An ingot produced by the sintering method is machined into a predetermined shape to prepare a sputtering target.

As shown in fig. 9, the sputtering gas discharge means has a plurality of gas discharge ports arranged in a row along the entire length of the slit that becomes the entrance of space portion 12. The number of discharge ports provided to the sputtering gas discharge unit was 20.

In addition, the shape of the first fixing element is a rectangular frame body, and the material of the first fixing element is stainless steel. The second fixing element is in a rectangular frame body, and the second fixing element is made of stainless steel.

< gas flow sputtering Condition >

Power supply: DC power supply

Power density: 44W/cm²

Sputtering gas pressure: 85Pa

Sputtering gas flow rate (sum of flow rates of respective discharge ports): ar: 21.8sccm/cm²

Total sputtering time: 250hr

Target shape: rectangular flat plate

Target size: 85mm (X direction) × 135mm (Y direction) × 20mmt

Total projected area of target: 230cm²

Target material: cu

Target relative density: 99 percent

The space S between the pair of flat plate targets before the start of sputtering₁：30mm

Distance D between the flat target and the substrate to be film-formed: 80mm

Material of the substrate to be film-formed: stainless steel

Size of the substrate to be subjected to film formation: 200mm x 3mmt

Temperature of substrate to be film-formed: 40 deg.C

Material of insulating shielding member: alumina (insulation breakdown voltage: 50kV)

Distance L1 between the flat target and the insulating shielding member: 0.5mm

Distance L3 between the lower surface of the upper panel of the insulating shielding member and the upper surface of the conductive fixing member: 0.1mm or less

Cooling of the target: using cooling water

A fixing method of fixing the fixing element and the insulating shielding member to the cooling device: screw connection

Insulating shielding member for cooling device: alumina (insulation breakdown voltage: 50kV)

In test example 1, sputtering was continued for the above sputtering time without using the interval adjustment mechanism. As a result, continuous sputtering can be performed for 5 hours or more per 1 lot without abnormal discharge in the initial stage of sputtering, but the average distance S between the pair of flat plate targets₁When the time is about 100 hours after the time exceeds 37mm, the abnormal discharge is increased and it is difficult to maintain the stabilitySputtering. Based on the results of this test, the relationship between the discharge time and the integrated power and the average reduced amount of the target thickness was determined. The sputtering rate of the test was 0.062g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 22%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 51%. Note that the average spacing S between a pair of plate targets in the test₁The measurement was performed with a vernier caliper.

(test example 2)

A sputtering film was formed under the same conditions as in test example 1, except that the gap adjustment mechanism was manually adjusted so that the change width of the average gap between the pair of flat plate targets was 5mm or less during sputtering based on the relationship between the discharge time and the integrated power and the average reduction amount of the target thickness, which were obtained in test example 1. As a result, in the test, abnormal discharge did not occur over a total sputtering time of 250 hours. The sputtering rate of the test was 0.069g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 26%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 46%.

(test example 3)

In sputtering, a sputtering film was formed under the same conditions as in experimental example 1 except that the sputtering chamber was opened periodically (every 10 hours), the weight of a pair of flat plate targets was measured, the width of change of the average interval was calculated therefrom, and interval adjustment was manually performed by an interval adjustment mechanism so that the width of change was 5mm or less. As a result, in the test, abnormal discharge did not occur over a total sputtering time of 250 hours. The sputtering rate of the test was 0.067g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 25%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 48%.

< 2. verification of Effect of insulating Shielding Member >

(test example 4)

A sputtering film was formed under the same sputtering conditions as in test example 1, except that the insulating shielding member was removed and a sputtering test was performed. In this case, abnormal discharge occurs between the target holder and another member having an anode potential, and stable film formation cannot be performed, and film formation is stopped immediately after the start. The observation of the inside of the sputtering chamber revealed that an abnormal discharge trace remained on the surfaces of the target and the fixing member.

(test example 5)

A sputtered film was formed under the same sputtering conditions as in test example 1, except that the flat target was brought into contact with the insulating shielding member with a gap L1 therebetween of 0. In this case, abnormal discharge frequently occurs between the target and the insulating shield, and the film formation is stopped at 30 minutes. The sputtering rate of the test was 0.064g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 31%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 44%.

(test example 6)

A sputtered film was formed under the same sputtering conditions as in test example 1, except that the distance L1 between the flat target and the insulating shielding member was set to 2.2 mm. In this case, although the film formation can be stably performed with a small amount of abnormal discharge at the beginning of the film formation, the abnormal discharge frequently occurs and the discharge is stopped after 3 hours. The fixed member was also sputtered as a result of checking the sputtering chamber. The sputtering rate of the test was 0.062g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 25%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 44%.

(test example 7)

A sputtered film was formed under the same sputtering conditions as in test example 1, except that the distance L1 between the flat target and the insulating shielding member was set to 0.1 mm. In this case, although the film formation can be stably performed with a small amount of abnormal discharge at the beginning of the film formation, the abnormal discharge frequently occurs after 2 hours has elapsed, and the discharge is stopped. The abnormal discharge trace was confirmed to remain between the target and the insulating shield in the sputtering chamber. The sputtering rate of the test was 0.067g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 30%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 51%.

(test example 8)

A sputtered film was formed under the same sputtering conditions as in test example 1, except that the distance L1 between the flat target and the insulating shielding member was set to 1.5 mm. In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. However, the fixed member was also sputtered as a result of checking the inside of the sputtering chamber. The sputtering rate of the test was 0.069g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 26%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 46%.

(test example 9)

A sputtered film was formed under the same sputtering conditions as in experimental example 1, except that the gas flow sputtering conditions were changed to the following conditions.

Power density: 22W/cm²

Sputtering gas pressure: 70Pa

Sputtering gas flow rate (sum of flow rates of respective discharge ports): ar: 32.7sccm/cm²

Target material: Cu-TiO₂-SiO₂

Target relative density: 95 percent

Distance L1 between the flat target and the insulating shielding member: 0.4mm

The space S between the pair of flat plate targets before the start of sputtering₁：20mm

In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. The sputtering chamber was checked and no abnormality was found. The sputtering rate of this test was 0.013g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 28%. Weight increase of insulating shielding member and target reduction after sputtering testThe weight ratio of the small amount is 48%.

The sputtered film of test example 9 was peeled off from the substrate and recovered. The film was then pulverized to obtain a fine powder. The sintered body was filled in a carbon mold, and hot-pressed under vacuum atmosphere, at 1000 ℃ for 2 hours, under a pressure of 30MPa to obtain a sintered body. Next, hot isotropic press working (HIP) is performed. The conditions of the hot isotropic press working were: the temperature rise rate was 300 ℃/hr, the holding temperature was 1000 ℃ and the holding time was 2 hours, the pressure of Ar gas was gradually increased from the start of temperature rise, and the pressure was increased at 150MPa while holding the temperature at 1000 ℃. And after the heat preservation is finished, the natural cooling is directly carried out in the furnace. The average diameter of the oxide particles in the sintered body was observed with a microscope and measured, and found to be 0.4 μm.

(test example 10)

A sputtered film was formed under the same sputtering conditions as in experimental example 1, except that the gas flow sputtering conditions were changed to the following conditions.

< gas flow sputtering Condition >

Power density: 28W/cm²

Sputtering gas pressure: 25Pa

Sputtering gas flow rate (sum of flow rates of respective discharge ports): ar: 14.2sccm/cm²

Target material: Cu-TiO₂

Target relative density: 97 percent

Target size: 143mm (X direction) × 493mm (Y direction) × 30mmt

Total projected area of target: 1410cm²

Distance L1 between the flat target and the insulating shielding member: 0.8mm

In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. In addition, no abnormality was found in the sputtering chamber by checking. The sputtering rate of the test was 0.011g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 40%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the reduced weight of the target was 42%。

(test example 11)

A sputtering target was mounted in the configuration shown in fig. 4 using a flat-plate target opposed-type gas flow sputtering apparatus having the configuration shown in fig. 1 and 2-1 (however, the mounting configuration of the sputtering target was the configuration shown in fig. 4) to form a sputtering film under the following conditions. A sputtering film was formed using the same apparatus configuration and sputtering conditions as in experimental example 1, except that the gas flow sputtering conditions were changed to the following conditions.

< gas flow sputtering Condition >

Distance L1 between the flat target and the insulating shielding member: 4.5mm

Distance L3 between the lower surface of the upper panel of the insulating shielding member and the upper surface of the conductive fixing member: 4.6mm

In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. However, the fixed member was also sputtered as a result of checking the inside of the sputtering chamber. The sputtering rate of this test was 0.028g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 48%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 37%.

(test example 12)

A sputtering target was mounted in the configuration shown in fig. 5 using a flat-plate target opposed-type gas flow sputtering apparatus having the configuration shown in fig. 1 and 2-1 (however, the mounting configuration of the sputtering target was the configuration shown in fig. 5) to form a sputtering film under the following conditions. A sputtering film was formed using the same apparatus configuration and sputtering conditions as in experimental example 1, except that the gas flow sputtering conditions were changed to the following conditions.

< gas flow sputtering Condition >

Distance L1 between the flat target and the insulating shielding member: 0.6mm

Distance L3 between the lower surface of the upper panel of the insulating shielding member and the upper surface of the conductive fixing member: 0.1mm

In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. However, for sputteringThe fixed member was also sputtered as a result of the confirmation in the chamber. The sputtering rate of this test was 0.034g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 44%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target after the sputtering test was 40%.

(test example 13)

A sputtering target was mounted in the configuration shown in fig. 6 by using a flat-plate target opposed-type gas flow sputtering apparatus having the configuration shown in fig. 1 and 2-1 (however, the mounting structure of the sputtering target was the configuration shown in fig. 6) to form a sputtering film under the following conditions. A sputtering film was formed using the same apparatus configuration and sputtering conditions as in experimental example 1, except that the gas flow sputtering conditions were changed to the following conditions.

< gas flow sputtering Condition >

Distance L1 between the flat target and the insulating shielding member: 0.6mm

Distance L3 between the lower surface of the upper panel of the insulating shielding member and the upper surface of the conductive fixing member: 0.5mm

In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. In addition, no abnormality was found in the sputtering chamber by checking. The sputtering rate of the test was 0.007g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 27%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 48%.

(test example 14)

A sputtering target was mounted in the configuration shown in fig. 7 by using a flat-plate target opposed-type gas flow sputtering apparatus having the configuration shown in fig. 1 and 2-1 (however, the mounting configuration of the sputtering target was the configuration shown in fig. 7) to form a sputtering film under the following conditions. A sputtering film was formed using the same apparatus configuration and sputtering conditions as in experimental example 1, except that the gas flow sputtering conditions were changed to the following conditions.

< gas flow sputtering Condition >

Power density: 33W/cm²

Sputtering gas pressure: 130Pa

Sputtering gas flow rate (sum of flow rates of respective discharge ports): ar: 33.3sccm/cm²

Target size: 100mm (X direction) × 150mm (Y direction) × 10mmt

Total projected area of target: 300cm²

The space S between the pair of flat plate targets before the start of sputtering₁：20mm

Distance L1 between the flat target and the insulating shielding member: 0.2mm

Distance L3 between the lower surface of the upper panel of the insulating shielding member and the upper surface of the conductive fixing member: 0.2mm

Material of the back sheet: cu (structure integrated with target)

In this case, the film formation can be stably performed with a small amount of abnormal discharge, and the film formation is completed as planned after 5 hours have elapsed. In addition, no abnormality was found in the sputtering chamber by checking. The sputtering rate of this test was 0.033g/h/cm². After the sputtering test, the ratio of the increased weight of the substrate to be film-formed to the decreased weight of the target was 24%. After the sputtering test, the ratio of the increased weight of the insulating shielding member to the decreased weight of the target was 48%.

[ description of reference ]

10a, 10b plate target

11 sputtering chamber

12 space part

13 sputtering particles

14 sputtering gas discharge port

15 DC power supply

16 parts for depositing sputtering particles

17 sputtering gas

18 support (holding member)

19 interval adjusting mechanism

20 exhaust port

22 gas discharge unit

24 inlet of gas exhaust unit

26 tubular member

28 gas inlet pipe

29 sealing material

45 conductive fixing member

45a first fixing element

45b second fixing element

46 diaphragm

47 back plate

48 cooling water

49 insulating shield member

491 peripheral wall

492 side plate

493 upper panel

50 cooling device

51 fastener

52 telescoping member

101 side of the target

102 mounting location

103 upper surface (sputtering surface) of plate target

104 lower surface of the mounting portion

106 lower surface of a plate target

501 insulating shield member for cooling device

502 fastener mounting base

503 fastening means

Claims (17)

1. A gas flow sputtering device is provided with:

a sputtering chamber, the interior of which can be evacuated; a pair of flat plate targets disposed in the sputtering chamber with a gap therebetween such that sputtering surfaces thereof face each other; a pair of cooling devices for cooling each of the plate targets; a conductive fixing member for fixing each flat target to the cooling device; one or more gas discharge ports for supplying a sputtering gas between the pair of flat plate targets; a member for depositing sputtering particles, which is disposed so as to face the gas discharge port and so as to be located on the opposite side of the gas discharge port with a space between the pair of flat plate targets interposed therebetween,

the pair of flat plate targets have mounting portions extending from respective side surfaces, and are fixed to the cooling device in a positional relationship in which the mounting portions are sandwiched between the fixing member and the cooling device,

the fixing member is covered with an insulating shielding member that does not contact the pair of flat targets.

2. The gas flow sputtering apparatus according to claim 1, wherein the pair of flat plate targets have conductivity.

3. The gas flow sputtering apparatus according to claim 1 or 2, wherein the pair of flat plate targets are fixed by the fixing member in a state where a surface opposite to a sputtering surface directly or indirectly contacts the cooling device.

4. The gas flow sputtering apparatus according to claim 1 or 2, wherein the closest distance between each flat target and the insulating shield member is adjusted to 0.1 to 5 mm.

5. The gas flow sputtering apparatus according to claim 1 or 2, wherein the insulating shield member is made of one or more materials selected from the group consisting of aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, yttrium oxide, calcium oxide, titanium oxide, and boron nitride.

6. The gas flow sputtering apparatus according to claim 1 or 2, wherein the insulating shield member has a peripheral wall that is erected around the side surface of each flat target at intervals along the side surface.

7. The gas flow sputtering apparatus according to claim 6, wherein the distance between the side surface of each flat target and the peripheral wall of the insulating shield member is 0.1 to 2 mm.

8. The gas-flow sputtering apparatus according to claim 1 or 2, wherein the insulating shield member is disposed so as to cover an edge portion of the sputtering surface of each flat target.

9. The gas flow sputtering apparatus according to claim 1 or 2, wherein the pair of flat plate targets is composed of a composite of a nonmagnetic material and a magnetic material.

10. The gas flow sputtering apparatus according to claim 1 or 2, wherein an upper surface of the mounting portion extending from the side surface is located at a position lower than an upper surface of the flat plate target.

11. The gas flow sputtering apparatus according to claim 1 or 2, wherein the conductive fixing member does not protrude more toward the upper side than the upper surface of the flat plate target.

12. A method for manufacturing a sputtering target material, comprising a step of sputtering using the gas flow sputtering apparatus according to any one of claims 1 to 11.

13. The manufacturing method according to claim 12, wherein the power density is set to 10W/cm²The sputtering is performed as described above.

14. The method of claim 12 or 13, wherein the amount of the additive is 1cm per unit of the substrate²The flow rate of the sputtering gas is set to 1sccm/cm in the total projected area of the opposed sputtering surfaces of the pair of flat plate targets²The sputtering is performed as described above.

15. The manufacturing method according to claim 12 or 13, wherein sputtering is performed with the pressure of the sputtering gas set to 10Pa or more.

16. The manufacturing method according to claim 12 or 13, wherein the member on which the sputtering particles are deposited is a used sputtering target, comprising a step of depositing the sputtering particles at an erosion portion of the sputtering target.

17. The manufacturing method according to claim 12 or 13, comprising: and a step of making the total mass of the sputtering particles deposited on the insulating shielding member larger than the mass of the sputtering particles deposited on the member on which the sputtering particles are deposited.

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