JP2013079420A - Sputtering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering apparatus capable of achieving high quality film deposition while preventing damage to targets.SOLUTION: The sputtering apparatus includes a film deposition chamber 1 which performs the film deposition on a substrate 13 internally disposed therein by sputtering, a power source 5 for forming plasma on the front surface side of the targets 2a and 2b disposed inside the film deposition chamber 1, permanent magnets 8a and 8b for producing confinement magnetic fields, and ring plates 6a and 6b for covering peripheral parts of the targets 2a and 2b disposed in the film deposition chamber 1. At least a surface layer part of the ring plates 6a and 6b is composed of an insulation material such as ceramic so that sputtering particles, which cause abnormal electric discharge and become a dust generating source, are prevented from piling up on the targets in a non-erosion region, thereby the high quality film formation is achieved while preventing damage to the targets.

Description

  The present invention relates to a sputtering apparatus that performs sputtering using plasma confined in a magnetic field.

A sputtering method using plasma, which is one of the thin film forming methods, is widely used for forming a thin film used in semiconductor devices and optical devices. For example, the sputtering method is used for forming a metal film or a transparent conductive film used as a wiring or an electrode. Sputtering is also used to form an insulator film made of oxide, nitride, fluoride, or the like.
Various types of sputtering apparatuses have been developed as sputtering apparatuses that perform film formation by sputtering. For example, as one of them, a facing target type sputtering apparatus having a pair of targets arranged to face each other is known (see, for example, Patent Documents 1 to 3). The facing target type sputtering apparatus is characterized in that film formation can be performed at a low temperature and damage to the substrate, which is a film formation target, can be suppressed by plasma.

FIG. 5 is a schematic sectional view showing a conventional facing target type sputtering apparatus.
As shown in the figure, a pair of targets 102 a and 102 b are disposed in the film formation chamber 101 so as to face each other with their front surfaces facing each other. In addition, the film formation chamber 101 includes an exhaust system (not shown) that exhausts and depressurizes the film formation chamber 101, and an air supply system (not shown) that supplies a sputtering gas such as argon gas into the film formation chamber 101. And are connected. The wall portion of the film formation chamber 101 is electrically connected to the ground potential. The negative electrode side of the DC power supply 103 is electrically connected to the targets 102a and 102b, respectively. The targets 102a and 102b function as cathode electrodes for generating plasma discharge.

On the front side of the targets 102a and 102b, frame-shaped deposition plates 104a and 104b are arranged so as to cover the peripheral portions of the targets 102a and 102b, respectively. The adhesion preventing plates 104a and 104b can prevent the sputtered particles from being deposited on the peripheral portion of the target where erosion does not progress, and can also function as an anode electrode for generating plasma discharge.
In addition, cylindrical permanent magnets 105a and 105b are arranged on the rear surfaces of the peripheral portions of the targets 102a and 102b, respectively. The permanent magnets 105a and 105b each have a magnetic pole at the end in the axial direction and are arranged so that different magnetic poles face each other, and generate a confined magnetic field for confining plasma in the space between the targets 102a and 102b. It is.
A substrate holder 107 that holds a substrate 106 that is a film formation target is installed on the side of the space between the targets 102a and 102b. The substrate holder 107 holds the substrate 106 with the film formation surface of the substrate 106 facing the space between the targets 102a and 102b.

Next, the operation of the facing target sputtering apparatus will be described.
First, the inside of the film forming chamber 101 is reduced to a predetermined pressure by an exhaust system. Thereafter, the pressure in the film forming chamber 101 is maintained at a predetermined pressure by the exhaust system.
Subsequently, a direct current voltage is applied to the targets 102 a and 102 b by the direct current power source 103 while supplying a sputtering gas such as argon gas into the film forming chamber 101 by the air supply system. As a result, plasma is generated in the space between the opposing targets 102a and 102b. The plasma is confined in the space between the targets 102a and 102b by the confinement magnetic field generated by the permanent magnets 105a and 105b.
Positive ions in the generated plasma collide with the target front surfaces of the targets 102a and 102b. Thereby, the target front surface is sputtered to generate sputtered particles, and erosion of the target front surface proceeds.
The sputtered particles fly and accumulate on the film formation surface of the substrate 106 held by the substrate holder 107. Thus, a thin film in which sputtered particles are deposited is formed on the film formation surface of the substrate 106.

Japanese Patent Laid-Open No. 10-46330 JP-A-10-330936 Japanese Patent Laid-Open No. 10-8246

In the conventional counter target type sputtering apparatus, the target is sputtered by positive ions in the plasma in a region where the magnetic field component parallel to the front surface of the target works stronger than the perpendicular magnetic field component. Therefore, such a region becomes an erosion region where erosion of the target proceeds. On the other hand, in the region where the magnetic field component perpendicular to the target surface works stronger than the parallel magnetic field component, it is difficult for cation ions in the plasma to reach the target surface, so that erosion hardly progresses. For this reason, especially the area | region where the magnet is arrange | positioned at the target rear surface side, and its peripheral area become a non-erosion area | region where erosion does not advance.
On the target surface in the non-erosion region, sputtered particles generated in a portion in the erosion region of the same target and sputtered particles flying from a portion in the erosion region of the opposing target are deposited. The deposit of sputtered particles causes abnormal discharge due to the difference in composition and density from the target. When an abnormal discharge occurs, the target may be damaged and become unusable, for example, the target may be cracked. Moreover, since the deposit of sputtered particles is peeled off by stress, it becomes a dust generation source that deteriorates the film quality of the thin film formed on the substrate.

Therefore, in the conventional counter target type sputtering apparatus, in order to prevent the deposition of sputtered particles on the target surface in the non-erosion region, as described above, the deposition preventing plate covers the peripheral portion of the target on the front side of the target. Is arranged.
However, the deposition preventing plate that also functions as the anode electrode is disposed with a distance of, for example, about 2 mm or more from the target in order to prevent a short circuit with the target that also functions as the cathode electrode. For this reason, sputtered particles flying from the opposing target enter the gap between the deposition plate and the target, and as a result, sputtered particles are deposited not only on the deposition plate but also on the target surface in the non-erosion region. . The deposition rate of sputtered particles on the target surface in the non-erosion region is covered with the deposition plate, so it is slower than the deposition rate on the deposition plate, but in proportion to the increase in the cumulative discharge time. The amount of sputtered particle deposits will increase. As described above, even when the deposition preventing plate is disposed, there is a problem that it is not sufficient to prevent the cause of abnormal discharge and the accumulation of sputtered particles serving as a dust generation source.

  Further, the boundary region between the non-erosion region and the erosion region is a region in which a magnetic field component parallel to the front surface of the target and a magnetic field component perpendicular to the target surface are mixed. For this reason, in the boundary region, sputtering of the target and deposition of sputtered particles on the target proceed simultaneously. Since plasma is generated above the boundary region, if the boundary region is covered with the deposition preventing plate, the deposition preventing plate comes into contact with the plasma and is damaged. Therefore, it is practically difficult to completely cover the target with the deposition preventing plate over the entire area outside the erosion region.

Even in a general magnetron sputtering method in which the target is disposed facing the film formation surface of the substrate, a portion that is not sputtered is generated on the front surface of the target. In this case, in the front surface of the target, the central portion and the outer peripheral edge portion are not sputtered, and the ring-shaped or racetrack-shaped portion excluding the central portion and the outer peripheral edge portion is sputtered. During sputtering, sputtered particles accumulate on a portion of the front surface of the target that is not sputtered, causing abnormal discharge and a source of dust generation.
As a countermeasure against inconvenience due to the non-sputtered part, the surface state is modified by performing a process such as mirror polishing on the front surface of the target, or by swinging the magnet disposed on the back side of the target, A part that is not sputtered is reduced.

  However, the countermeasure for swinging the magnet is complicated in apparatus configuration, and it is difficult to completely prevent the non-sputtered portion of the outer peripheral edge of the target surface from being generated only by swinging the magnet.

  The present invention has been made against the background of the above circumstances, and an object thereof is to provide a sputtering apparatus capable of realizing high-quality film formation while preventing damage to a target.

  That is, in the sputtering apparatus of the present invention, the first aspect of the present invention is a film forming chamber for performing film formation by sputtering on a substrate disposed inside, and a plasma on a front side of a target disposed in the film forming chamber. A plasma generation unit for generating, a magnetic field generation unit for generating a confinement magnetic field that surrounds and confines the plasma on the front side of the target, and a ring plate that covers a peripheral portion of the target disposed in the film formation chamber, The ring plate is characterized in that at least the surface layer portion is made of an insulating material.

  The sputtering apparatus of the second aspect of the present invention is characterized in that, in the first aspect of the present invention, the insulating material is ceramic.

  In the sputtering apparatus of the third aspect of the present invention, in the first or second aspect of the present invention, the ring plate is formed along the inner peripheral edge of the non-erosion region generated at the peripheral edge of the target during the sputtering, or on the inner peripheral side thereof or on the outer peripheral side thereof. It has a shape in which the inner peripheral edge is located on the side.

  A sputtering apparatus according to a fourth aspect of the present invention is characterized in that, in any one of the first to third aspects of the present invention, the ring plate is in contact with the target surface without a gap.

  A sputtering apparatus according to a fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects of the present invention, a part or all of the surface of the ring plate is subjected to a thermal spraying process.

  The sputtering apparatus of the sixth aspect of the present invention is characterized in that, in the fifth aspect of the present invention, the surface of the ring plate is roughened by the thermal spraying process.

  A sputtering apparatus according to a seventh aspect of the present invention is characterized in that, in the fifth or sixth aspect of the present invention, the thermal spraying treatment uses ceramics as a thermal spray material.

  The sputtering apparatus according to an eighth aspect of the present invention is the deposition apparatus according to any one of the first to seventh aspects, wherein the sputtering apparatus is positioned in front of the ring plate at a peripheral portion of the target disposed in the film forming chamber. A board is arranged.

  A sputtering apparatus according to a ninth aspect of the present invention is characterized in that, in the eighth aspect of the present invention, the deposition preventing plate is in contact with the ring plate without a gap.

  A sputtering apparatus according to a tenth aspect of the present invention is characterized in that, in the eighth and ninth aspects of the invention, a part or all of the surface of the deposition preventing plate is subjected to a thermal spraying process.

  The sputtering apparatus according to an eleventh aspect of the present invention is characterized in that, in the tenth aspect of the present invention, the surface of the deposition preventing plate is roughened by the thermal spraying process.

  A sputtering apparatus according to a twelfth aspect of the present invention is characterized in that, in the tenth or eleventh aspect of the present invention, the thermal spraying treatment uses a conductive material as a thermal spraying material.

  A sputtering apparatus according to a thirteenth aspect of the present invention is characterized in that, in any of the eighth to twelfth aspects of the present invention, the deposition preventing plate functions as an electrode of the plasma generation unit.

  A sputtering apparatus according to a fourteenth aspect of the present invention is the sputtering apparatus according to any one of the first to thirteenth aspects of the present invention, wherein the targets are made of a pair and face each other in the film formation chamber with the front surfaces of the targets facing each other. It is characterized by being.

  In the sputtering apparatus of the fifteenth aspect of the present invention, in any one of the first to thirteenth aspects of the present invention, the target is disposed so as to face the film formation surface of the substrate with the front surface of the target facing. Features.

  A sputtering apparatus according to a sixteenth aspect of the present invention is the sputtering apparatus according to any one of the first to fifteenth aspects, wherein the magnetic field generating unit is composed of a magnet, and the magnetic pole of the magnet is disposed in the film forming chamber. It is installed so that it may be located in the side or outer peripheral side.

That is, according to the present invention, a ring plate that covers the peripheral portion of the target with respect to the target disposed in the deposition chamber is provided, and at least the surface layer portion of the ring plate is made of an insulating material. It is possible to prevent the cause of abnormal discharge and sputtered particles that become a dust generation source from directly depositing on the peripheral edge of the target in the non-erosion region. Therefore, according to the present invention, it is possible to realize high-quality film formation while preventing damage to the target.
In the present invention, the erosion region is a region where erosion (thickness reduction) proceeds by sputtering.
Further, the non-erosion region referred to in the present invention is a region where spatter does not occur, thickness reduction does not occur, and sputtered particles are partially deposited.
In the erosion region and the non-erosion region, there is a boundary region in which sputter and deposition of sputtered particles coexist and the thickness does not decrease or does not proceed at a certain depth. The above-described certain depth can be determined as appropriate.

The target is not limited to one having a specific shape, but may have a shape in which a portion other than the peripheral portion of the target front surface is located in the erosion region. When the target has such a shape, erosion of the target can be efficiently advanced. In this specification, the target front surface means a surface on the plasma side on which the target is sputtered unless otherwise specified.
The target material is not limited to a specific material, and can be appropriately selected from a metal material, a semiconductor material, an insulator material, and the like according to the type of thin film to be deposited on the substrate. Specifically, a transparent conductive film or a metal film can be formed, or a thin film that is an electrically insulating material such as an oxide, nitride, or fluoride can be formed from a conductive target.

  In addition, a substrate to be formed is not limited to a specific substrate, and a thin film can be formed on a semiconductor substrate, a glass substrate, or any other substrate. In addition, the substrate referred to in the present invention includes those in which a metal film, a semiconductor film, an insulator film, or the like is formed on a semiconductor substrate, a glass substrate, or another substrate.

  At least the surface layer portion of the ring plate is made of an insulating material. The material of the insulating material is not particularly limited, but for example, ceramics can be used as the insulating material. Ceramics are excellent in plasma resistance and can prevent the ring plate from being damaged by the plasma. In particular, high-purity alumina is excellent in plasma resistance and vacuum resistance, and therefore can effectively prevent the ring plate from being damaged.

  The ring plate may have a shape in which the inner peripheral edge is located along or on the inner peripheral side of the non-erosion region generated at the target peripheral edge during sputtering. In this case, the front surface of the target in the non-erosion region is entirely covered by the ring plate. Therefore, it is possible to prevent the cause of abnormal discharge and the deposition of sputtered particles that become a dust generation source on the peripheral portion of the target.

  In addition, the ring plate may have a shape in which the inner peripheral edge of the ring plate is positioned on the outer peripheral side of the inner peripheral edge of the non-erosion region generated at the target peripheral edge during sputtering. Even in this case, in the front surface of the target, sputtering of the target and deposition of sputtered particles proceed simultaneously, and in the boundary region between the erosion region and non-erosion region, the sputtering of the target and deposition of sputtered particles proceed simultaneously. Therefore, the deposition of sputtered particles is suppressed, and the amount of deposition is suppressed to a small amount even if it is not covered with the ring plate. Therefore, even if the inner peripheral edge of the ring plate is positioned on the outer peripheral side of the inner peripheral edge of the non-erosion region, the ring plate is effective for depositing sputtered particles that are the cause of abnormal discharge and the dust generation source on the peripheral edge of the target. Can be prevented.

  Further, the ring plate can be brought into contact with the target surface without any gap. Since the ring plate is in contact with the target surface without any gap, it is possible to prevent sputter particles from wrapping around between the ring plate and the target surface during sputtering. Can be reliably prevented.

Further, the ring plate may be subjected to a thermal spraying process on a part or all of its surface. By performing the thermal spraying process, the ring plate surface can be modified so that the sputtered particles deposited on the ring plate surface are difficult to peel off. Specifically, for example, the ring plate surface can be roughened by thermal spraying. The sputtered particles deposited on the ring plate surface are stably held on the roughened ring plate surface. For this reason, it becomes difficult to separate the sputtered particles from the ring plate surface. Thus, by performing the thermal spraying process, it is possible to prevent the sputtered particles deposited on the surface of the ring plate from peeling off and contaminating the thin film formed on the substrate.
Various materials can be used as the thermal spraying material used for the thermal spraying treatment applied to the surface of the ring plate. For example, ceramics can be used. Since the ceramic has plasma resistance, the ring plate can be prevented from being damaged by the plasma. In addition, the said thermal spraying process may be performed on the insulating material which comprises a ring plate, and the sprayed layer itself may comprise the insulating material of a ring plate surface layer part.

  An adhesion-preventing plate that prevents deposition of sputtered particles on the periphery of the target may be disposed on the periphery of the target so as to be positioned in front of the ring plate. In this case, since the ring plate is disposed between the peripheral edge of the target and the deposition preventing plate, it is possible to suppress the sputter particles from entering between the deposition preventing plate and the peripheral edge of the target. Deposition on the periphery of the target can be prevented.

The adhesion preventing plate can be disposed so as to contact the ring plate without a gap. By disposing the adhesion preventing plate so as to be in contact with the ring plate without a gap, it is possible to prevent sputter particles from entering between the adhesion preventing plate and the ring plate during sputtering.
In addition, the material of an adhesion prevention board is not specifically limited as this invention, A metal, a semiconductor, and a nonmetallic material can be selected suitably. Further, the deposition preventing plate can be made of a conductive material so as to function as an electrode of a plasma generation unit described later.

Further, the deposition preventing plate may be subjected to a thermal spraying process on part or all of its surface. By performing the thermal spraying process, the surface of the deposition preventing plate can be modified so that the sputtered particles deposited on the surface of the deposition preventing plate are difficult to peel off. Specifically, for example, the surface of the deposition preventing plate can be roughened by a thermal spraying process. The roughened deposition preventing plate surface can stably hold the sputtered particles deposited on the deposition preventing plate surface. For this reason, it becomes difficult to separate the sputtered particles from the surface of the deposition preventing plate. Thus, by performing the thermal spraying process, it is possible to prevent the sputtered particles deposited on the surface of the deposition preventing plate from being peeled off and contaminating the thin film formed on the substrate.
In addition, although various materials can be used as a thermal spraying material used for the thermal spraying process performed on the deposition preventing plate surface, for example, a conductive material such as an aluminum material can be used.

The plasma generation unit may be any unit as long as it can generate plasma on the front side of the target disposed in the film formation chamber, and the configuration is not particularly limited in the present invention. For example, the plasma generation unit can be configured by a cathode electrode, an anode electrode, and a power source that applies a voltage therebetween. As the power source, a DC power source or a high frequency power source can be appropriately selected and used depending on the type of thin film to be formed. The cathode electrode can also serve as a target. Further, the anode electrode can also serve as an adhesion preventing plate or a film formation chamber wall.
Further, when a high frequency power source is used in a case where a pair of targets are arranged opposite to each other as will be described later, for example, each of the targets arranged opposite to each other can alternately serve as a cathode electrode.

The magnetic field generation unit only needs to generate a confined magnetic field that surrounds and confines the plasma generated by the plasma generation unit on the front side of the target, and the configuration is not limited to a specific one. For example, the magnetic field generation unit can be configured by a pair of magnet units arranged so that different magnetic poles face each other, and each magnet unit is formed in a circumferential shape. Each magnet part may be constituted by a plurality of magnets arranged in a circumferential shape, or may be constituted by a magnet integrally formed in a circumferential shape. The magnet may be a permanent magnet or an electromagnet.
The magnet constituting the magnetic field generation unit can be installed so that its magnetic pole is located on the back side or the outer peripheral side of the target arranged in the film forming chamber.

The sputtering apparatus of the present invention can be configured as a counter target type sputtering apparatus by arranging the pair of targets so that the front surfaces of the targets face each other and are opposed to each other with a space therebetween. In this case, the ring plate and the deposition preventive plate can be arranged as described above with respect to the targets arranged to face each other. Further, the substrate to be deposited is disposed on the side of the space between the opposing targets. According to such a facing target type sputtering apparatus, film formation can be performed at a low temperature, and damage to the substrate due to plasma can be suppressed.
Moreover, the sputtering apparatus of this invention can also use the said single target. In this case, it can be configured so as to be opposed to the film formation surface of the substrate with the front surface of the target facing.

  As described above, according to the present invention, it is possible to prevent the sputter particles that are the cause of abnormal discharge and the dust generation source from directly depositing on the peripheral edge of the target in the non-erosion region outside the erosion region. High-quality film formation can be realized while preventing damage to the target.

It is a schematic sectional drawing which shows the sputtering device of one Embodiment of this invention. Similarly, it is a schematic sectional drawing which shows a use condition. Similarly, it is the schematic which shows the erosion state of the target in a sputtering device with the erosion state of the target in the conventional sputtering device. It is the schematic which shows the erosion state of the target in the sputtering device of other embodiment of this invention. It is a schematic sectional drawing which shows the conventional facing target type sputtering device.

(Embodiment 1)
A sputtering apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic sectional view showing a sputtering apparatus of this embodiment, FIG. 2 shows an erosion state of a target in the sputtering apparatus of this embodiment, and FIG. 3 shows an erosion state of the target in the sputtering apparatus of this embodiment and a conventional one. It is the expanded schematic which shows the erosion state of the target in a sputtering device.

  The sputtering apparatus of this embodiment is of a counter target type. As shown in FIG. 1, a pair of targets 2a and 2b are disposed in the film formation chamber 1 so as to face each other in the vertical direction with the target front surfaces 2a1 and 2b1 facing each other. Further, a backing plate that cools the target and functions as an electrode may be provided on the rear surface side of the target. The backing plate material is not limited to a specific material, and various materials can be appropriately selected.

The film forming chamber 1 is connected to an exhaust system 3 that exhausts the pressure in the film forming chamber 1 to reduce the pressure, and an air supply system 4 that supplies a sputtering gas such as argon gas into the film forming chamber 1. . As a sputtering gas supplied into the film forming chamber 1, an inert gas such as an argon gas can be used. Further, by adding a reactive gas such as oxygen gas or nitrogen gas to the inert gas, a thin film of oxide, nitride, or the like can be formed.
The outputs 2 of the power source 5 are electrically connected to the targets 2a and 2b, respectively. Further, the other output end of the power source 5 is electrically connected to the side wall of the film forming chamber 1. Thereby, the targets 2a and 2b and the film formation chamber 1 function as electrodes for generating plasma discharge.

Ring plates 6a and 6b covering the peripheral edges of the targets 2a and 2b are in contact with the surfaces of the targets 2a and 2b without any gaps. The ring plates 6a and 6b are made of an insulating material, specifically, for example, made of ceramics having excellent plasma resistance.
The ring plates 6a and 6b have a shape in which the inner peripheral edge is positioned along the inner peripheral edge of the non-erosion regions 11a and 11b generated at the peripheral edges of the targets 2a and 2b, respectively, during sputtering (see FIG. 3A). The inner peripheral edges of the ring plates 6a and 6b may be located on the inner peripheral side of the inner peripheral edges of the non-erosion regions 11a and 11b.

  It should be noted that in the portions between the non-erosion regions 11a and 11b and the erosion regions 10a and 10b described later in the targets 2a and 2b, spattering and deposition occur simultaneously, respectively, and the thickness does not decrease or the erosion has a constant depth. Thus, the boundary regions 12a and 12b do not travel.

  The surfaces of the ring plates 6a and 6b are each subjected to a thermal spraying process using ceramics as a thermal spray material. Thereby, the surfaces of the ring plates 6a and 6b are roughened. The thermal spraying process may be performed on a part of the surface of the ring plates 6a and 6b, or may be performed on the entire surface. In the present invention, the surface of the ring plates 6a and 6b may not be sprayed.

Further, in the film forming chamber 1, frame-shaped deposition plates 7a and 7b are respectively positioned in front of the ring plates 6a and 6b at the peripheral portions of the targets 2a and 2b on which the ring plates 6a and 6b are formed. Has been placed. The adhesion preventing plates 7a and 7b are in contact with the ring plates 6a and 6b without any gaps, respectively. Further, the inner peripheral edges of the deposition preventing plates 7a and 7b are located on the outer peripheral side of the inner peripheral edges of the ring plates 6a and 6b, respectively (see FIG. 2A). Note that the inner peripheral edges of the deposition preventing plates 7a and 7b may be positioned along the inner peripheral edges of the ring plates 6a and 6b, respectively.
The deposition preventing plates 7a and 7b function as anode electrodes for preventing the deposition of sputtered particles on the peripheral portions of the targets 2a and 2b, respectively, and generating plasma discharge.

  The surfaces of the deposition preventing plates 7a and 7b are each subjected to a thermal spraying process using a conductive material such as an aluminum material as a thermal spraying material. Thereby, the surface of the adhesion prevention plates 7a and 7b is roughened. The thermal spraying process may be performed on a part of the surface of the deposition preventing plates 7a and 7b or on the entire surface. Moreover, as this invention, you may not perform a thermal spraying on the surface of the adhesion prevention plates 7a and 7b.

In the film forming chamber 1, permanent magnets 8a and 8b are arranged on the rear surfaces of the targets 2a and 2b, respectively. The permanent magnets 8a and 8b are arranged so that different magnetic poles face each other. Further, the permanent magnets 8a and 8b are arranged in a circumferential shape along the peripheral edges of the targets 2a and 2b, respectively. Permanent magnets 8a and 8b may be formed integrally with each other, or may be composed of a plurality of divided magnets.
The permanent magnets 8a and 8b correspond to a magnetic field generation unit of the present invention that generates a confined magnetic field for confining the plasma 9 in the space between the targets 2a and 2b. In FIG. 2, the magnetic field lines of the magnetic field formed by the permanent magnets 8a and 8b are indicated by broken lines.

  The power source 5, the targets 2 a and 2 b as electrodes, and the film forming chamber 1 constitute a plasma generation unit of the present invention that generates plasma 9 on the front side of the targets 2 a and 2 b. Further, when the deposition preventing plates 7a and 7b act as electrodes, the deposition preventing plates 7a and 7b also function as plasma generation units. Inside the confined magnetic field, erosion regions 10a and 10b are formed in which erosion is generated in the targets 2a and 2b by the plasma 9 generated by the plasma generator.

  A substrate holder 14 for holding a substrate 13 that is a film formation target is installed on the side of the space between the targets 2a and 2b. The substrate holder 14 holds the substrate 13 with the film formation surface of the substrate 13 facing the space between the targets 2a and 2b. The substrate 13 is, for example, a semiconductor substrate or a glass substrate.

Next, the operation of the sputtering apparatus will be described with reference to FIGS.
First, the inside of the film forming chamber 1 is reduced to a predetermined pressure by the exhaust system 3. Thereafter, the pressure in the film forming chamber 1 is maintained at a predetermined pressure by the exhaust system 3.

  Subsequently, a voltage is applied between the targets 2 a and 2 b and the film forming chamber 1 by the power source 5 while supplying a sputtering gas such as argon gas into the film forming chamber 1 by the air supply system 4. As a result, plasma 9 is generated in the space between the opposing targets 2a and 2b. The plasma 9 is confined in the space between the targets 2a and 2b by the confinement magnetic field generated by the permanent magnets 8a and 8b. Thus, erosion regions 10a and 10b are formed inside the confined magnetic field, where the plasma 9 causes erosion on the targets 2a and 2b.

  In the erosion regions 10a and 10b, positive ions in the generated plasma 9 collide with the target front surfaces 2a1 and 2b1 of the targets 2a and 2b, respectively. Thereby, the target front surfaces 2a1 and 2b1 are sputtered to generate sputtered particles, and the erosion of the target front surfaces 2a1 and 2b1 proceeds.

  The sputtered particles fly and accumulate on the film forming surface of the substrate 13 held by the substrate holder 14. Thus, a thin film in which sputtered particles are deposited is formed on the film formation surface of the substrate 13.

2 and 3 show the erosion of the target in the sputtering apparatus of the present embodiment and the erosion of the target in the conventional sputtering apparatus.
3A shows the erosion of the target in the sputtering apparatus of the present embodiment. In FIG. 3A, the right figure is a plan view of the target front side showing the target and its periphery, and the left figure is A- in the right figure. It is an A line expanded sectional view.
3B shows the erosion of the target in the conventional sputtering apparatus shown in FIG. 5. In FIG. 3B, the right figure is a plan view of the target front side showing the target and its periphery, and the left figure is the right figure. It is a BB line expanded sectional view.

In the sputtering apparatus of the present embodiment, ring plates 6a and 6b are disposed between the peripheral portions of the targets 2a and 2b and the deposition preventing plates 7a and 7b, respectively. The ring plates 6a and 6b have shapes in which the inner peripheral edge is located along or on the inner peripheral edge of the non-erosion regions 11a and 11b, respectively. By disposing such ring plates 6a and 6b, it is possible to reliably prevent the sputtered particles from entering between the peripheral portions of the targets 2a and 2b and the deposition preventing plates 7a and 7b.
Further, the surfaces of the ring plates 6a and 6b and the surfaces of the deposition preventing plates 7a and 7b are each subjected to thermal spraying to be roughened. For this reason, even if sputtered particles are deposited on the ring plates 6a and 6b and the adhesion preventing plates 7a and 7b, the deposited sputtered particles can be prevented from peeling off.
Therefore, according to the sputtering apparatus of the present embodiment, it is possible to realize high-quality film formation while preventing damage to the targets 2a and 2b.

  On the other hand, in the conventional sputtering apparatus shown in FIG. 5, as shown in FIG. 3B, there are gaps between the peripheral portions of the targets 102a and 102b and the deposition preventing plates 104a and 104b. For this reason, sputtered particles wrap around between the peripheral portions of the targets 102a and 102b and the deposition preventing plates 104a and 104b. As a result, sputtered particles that cause abnormal discharge and generate dust are deposited on the peripheral portions of the targets 102a and 102b.

(Embodiment 2)
Next, a sputtering apparatus according to another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic diagram showing target erosion in the sputtering apparatus of the present embodiment. In FIG. 4, the right figure is a plan view of the target front side showing the target and its periphery, and the left figure is a CC line of the right figure. It is an expanded sectional view. In addition, about the structure similar to the said Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted or simplified.

  The sputtering apparatus according to the present embodiment has the same configuration as that of the first embodiment except for the shapes of the ring plates 16a and 16b disposed between the peripheral portions of the targets 2a and 2b and the deposition preventing plates 7a and 7b. ing.

As shown in FIG. 3, ring plates 16a and 16b are formed on the targets 2a and 2b so as to be in contact with the surfaces of the targets 2a and 2b without any gaps. The ring plates 16a and 16b are made of an insulating material such as ceramics, for example, like the ring plates 6a and 6b. The surfaces of the ring plates 16a and 16b are roughened by a thermal spraying process using ceramics as a thermal spray material, for example. In the present invention, the ring plates 16a and 16b may not be sprayed.
The ring plates 16a and 16b have a shape in which the inner peripheral edge is located on the outer peripheral side of the inner peripheral edge of the non-erosion regions 11a and 11b generated at the peripheral edges of the targets 2a and 2b, respectively, during sputtering.

  In the film forming chamber 1, frame-shaped deposition prevention plates 7a and 7b are arranged at the peripheral portions of the targets 2a and 2b on which the ring plates 16a and 16b are formed, respectively, in front of the ring plates 16a and 16b. ing. The adhesion prevention plates 7a and 7b are in contact with the ring plates 16a and 16b without any gaps, respectively. Further, the inner peripheral edges of the deposition preventing plates 7a and 7b are located on the inner peripheral side of the inner peripheral edges of the ring plates 16a and 16b, respectively, and are positioned along or on the outer peripheral side of the non-erosion region 11. Yes.

Thus, in the sputtering apparatus of Embodiment 2, the inner peripheral edges of the ring plates 16a and 16b are positioned on the outer peripheral side of the inner peripheral edges of the non-erosion regions 11a and 11b, respectively. Therefore, of the non-erosion regions 11a and 11b, the portions on the erosion regions 10a and 10b side are not covered with the ring plates 16a and 16b, but the outer peripheral side portion where most of the sputtered particles are deposited is the ring plate 16a, 16b.
Further, in the boundary regions 12a and 12b between the erosion regions 10a and 10b and the non-erosion regions 11a and 11b, the sputtering of the targets 2a and 2b and the deposition of the sputtered particles proceed at the same time. Therefore, the problem caused by the deposition of sputtered particles is smaller than that on the outer peripheral side.
Therefore, also in the second embodiment, the ring plates 16a and 16b can effectively prevent the sputtered particles from flowing between the peripheral portions of the targets 2a and 2b and the deposition preventing plates 7a and 7b.

  In the above embodiment, the case where the pair of targets are arranged to face each other in the vertical direction has been described. However, the direction in which the pair of targets are arranged to face each other is not limited to the vertical direction. The pair of targets can be arranged to face each other in any direction, and can be arranged to face each other in the horizontal direction in addition to the vertical direction.

  In the above-described embodiment, a description has been given of a counter-target type sputtering apparatus in which a pair of targets are arranged opposite to each other in the film forming chamber. However, a plurality of pairs may be used, and targets may not be paired. May be. For example, the present invention can be applied to a sputtering apparatus in which a front surface of a target is disposed facing a film formation surface of a substrate that is a film formation target.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to the content of the said embodiment, A suitable change is possible.

Using the sputtering apparatus shown in FIG. 1 (Invention Example 1), the sputtering apparatus shown in FIG. 4 (Invention Example 2), and the sputtering apparatus shown in FIG. 5 (Comparative Example), a Si target having a thickness of 5 mm was used as the target. Then, continuous discharge was performed. The continuous discharge conditions were as follows: the flow rate of argon gas supplied into the film formation chamber as a sputtering gas was set to 50 sccm, the pressure in the film formation chamber was set to 0.5 Pa, and the input power from the power source was set to 2.5 W / cm ² .

As a result of the above continuous discharge, in the comparative example, when 150 hours passed from the start of the discharge, the deposit of sputtered particles deposited on the target under the deposition preventing plate peeled off. Thereafter, the number of peeled materials increased with the passage of time, and the target cracked.
On the other hand, in Invention Example 1 and Invention Example 2, in both cases, the peeled material observed in the comparative example was not observed even after 300 hours had elapsed from the start of discharge, which is the life of the target. No cracks occurred.

DESCRIPTION OF SYMBOLS 1 Deposition chamber 2a Target 2a1 Target front surface 2b Target 2b1 Target front surface 3 Exhaust system 4 Air supply system 5 Power supply 6a Ring plate 6b Ring plate 7a Depositing plate 7b Depositing plate 8a Permanent magnet 8b Permanent magnet 9 Plasma 10a Erosion region 10b Erosion Region 11a Non-erosion region 11b Non-erosion region 12a Boundary region 12b Boundary region 13 Substrate 14 Substrate holder 16a Ring plate 16b Ring plate

Claims (16)

A film formation chamber for performing film formation by sputtering on a substrate disposed inside;
A plasma generation unit for generating plasma on the front side of the target disposed in the film formation chamber;
A magnetic field generation unit for generating a confined magnetic field for enclosing and confining the plasma on the front side of the target;
A ring plate covering a peripheral edge of the target disposed in the film formation chamber,
The sputtering apparatus according to claim 1, wherein at least a surface layer portion of the ring plate is made of an insulating material.   The sputtering apparatus according to claim 1, wherein the insulating material is ceramic.   3. The ring plate according to claim 1, wherein the ring plate has a shape in which an inner peripheral edge is located along an inner peripheral edge of the non-erosion region generated at the peripheral edge of the target during the sputtering, or an inner peripheral side or an outer peripheral side thereof. The sputtering apparatus described.   The sputtering apparatus according to claim 1, wherein the ring plate is in contact with the target surface without a gap.   The sputtering apparatus according to claim 1, wherein a part or all of the surface of the ring plate is sprayed.   The sputtering apparatus according to claim 5, wherein the surface of the ring plate is roughened by the thermal spraying process.   The sputtering apparatus according to claim 5 or 6, wherein the thermal spraying treatment uses ceramics as a thermal spray material.   The sputtering apparatus according to claim 1, wherein a deposition preventing plate is disposed in front of the ring plate at a peripheral portion of the target disposed in the film forming chamber. .   The sputtering apparatus according to claim 8, wherein the deposition preventing plate is in contact with the ring plate without a gap.   The sputtering apparatus according to claim 8 or 9, wherein a part or all of the surface of the deposition preventing plate is subjected to a thermal spraying process.   The sputtering apparatus according to claim 10, wherein the surface of the deposition preventing plate is roughened by the thermal spraying process.   The sputtering apparatus according to claim 10 or 11, wherein the thermal spraying treatment uses a conductive material as a thermal spray material.   The sputtering apparatus according to claim 8, wherein the deposition preventing plate functions as an electrode of the plasma generation unit.   The sputtering apparatus according to any one of claims 1 to 13, wherein the targets are in pairs and are arranged to face each other with a gap in the film formation chamber with the front surfaces of the targets facing each other.   The sputtering apparatus according to claim 1, wherein the target is disposed so as to face the film-forming surface of the substrate with the front surface of the target facing.   The magnetic field generation part is made of a magnet, and the magnetic pole of the magnet is installed so as to be located on the back side or the outer peripheral side of the target arranged in the film forming chamber. The sputtering apparatus in any one.

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