Patent Application
20130098757
The present invention generally relates to a sputter deposition apparatus and an adhesion-preventing member.
SiO2 thin films are used for protection films for channel layers in thin film transistors (TFT) and barrier films for blue glass plates. Recently, as a method for the formation of a SiO2 thin film on a surface of an area-increased substrate, reactive sputtering is generally performed for sputtering, while an Si target is being subjected to a chemical reaction in an O2 gas ambience.
The magnet device 1261 is arranged on a rear surface side of the backing plate 1221. The magnet device 1261 includes a center magnet 127b1, disposed linearly on a magnet fixing plate 127c1, and an outer peripheral magnet 127a1 on a magnet fixing plate 127c1 that is parallel to the backing plate 1221, and the outer peripheral magnet 127a1 which surrounds the center magnet 127b1 in a ring shape at a predetermined distance from the peripheral edge of the center magnet 127b1. The outer peripheral magnet 127a1 and the center magnet 127b1 are respectively disposed in a manner such that their magnet poles of opposite polarities from each other facing the rear surface of the target 1211.
A moving device 129 is arranged on a rear side of the magnet device 1261, and the magnet device 1261 is fixed to the moving device 129. The moving device 129 is configured to move the magnet device 1261 in a direction parallel to the rear surface of the target 1211.
When explaining the overall structure of the sputter deposition apparatus 110, the target units of the sputter units 1201 to 1204 are arranged in a line spaced apart from each other inside the vacuum chamber 111, and the surfaces of the targets 1211 to 1214 of the target units are arranged in order on the same plane. Each of the backing plates 1221 to 1224 is attached to a wall face of the vacuum chamber 111 via an insulator 114, and electrically insulated with the vacuum chamber 111.
Metallic adhesion-preventing members 1251 to 1254 are stood up outside the outer peripheries of the respective the backing plates 1221 to 1224, while being spaced from the outer peripheries of the respective backing plates 1221 to 1224. The adhesion-preventing members 1251 to 1254 are electrically connected to the vacuum chamber 111. Tip portion of the respective adhesion-preventing members 1254 to 1254 are bent at a right angle toward the outer peripheries of the targets 1211 to 1214 in the sputter units 1201 to 1204 and surround the surfaces of the targets 1211 to 1214 in ring shapes such that the tip portions cover the peripheral portions of the backing plates 1221 to 1224 in the respective sputter units 1201 to 1204. The portions of the surfaces of the respective targets 1211 to 1214, which are exposed from the inner peripheries of the adhesion-preventing members 1254 to 1254, are referred to as sputtering surfaces.
When a method for the formation of a SiO2 thin film on a surface of a substrate 131 is explained by using the conventional sputter deposition apparatus 110, a vacuum evacuation device 112 is connected to an exhaust opening of the vacuum chamber 111, and the interior of the vacuum chamber 111 is preliminarily evacuated to vacuum. The substrate 131 is mounted on a substrate holder 132, which is transferred into the vacuum chamber 111 and stopped at a position spaced from and opposed to the sputtering surfaces of the respective targets 1211 to 1214.
When a gas introduction system 113 is connected to an introduction opening of the vacuum chamber 111 and a mixed gas of an Ar gas as a sputtering gas and an O2 gas as a reactive gas is introduced into the vacuum chamber 111, the O2 gas forms an oxide SiO2 through a reaction with the surfaces of the respective targets 1211 to 1214.
When an electric power supply 137 is electrically connected to the respective backing plates 1221 to 1224 and AC voltages having opposite polarities from each other are applied to two adjacent targets, while one of the two adjacent targets is placed at a positive potential, the other is placed at a negative potential. Thus, an electric discharge is generated between the adjacent targets, and Ar gas among the targets 1211 to 1214 and the substrate 131 is plasmatized.
Alternatively, it is acceptable that the electric power supply 137 is electrically connected to each of the backing plates 1221 to 1224 and the substrate holder 132; AC voltages having opposite polarities from each other are applied to each of the targets 1211 to 1214 and the substrate 131, the electric discharge is generated between the targets 1211 to 1214 and the substrate 131; and Ar gas between each of the targets 1211 to 1214 and the substrate 131 is plasmatized. This method can also be carried out in a case of a single target.
Ar ions in the plasma are trapped in magnetic fields formed at surfaces on the targets 1211 to 1214 opposite to the backing plates 1221 to 1224 by the magnet devices 1261 to 1264. When each of the targets 1211 to 1214 is put in a negative potential, the Ar ions are crashed onto the sputtering surfaces of the targets 1211 to 1214, thereby flicking particles of SiO2.
With respect to the magnetic field formed on each of the targets 1211 to 1214, since the above-mentioned magnet devices 1261 to 1264 become structurally non-uniform, the Ar ions concentrate at portions having a relatively high magnetic density, so that the targets 1211 to 1214 are shaved faster as compared to portions around them. In order to prevent the formation of those portions (erosion) of the targets 1211 to 1214 which are locally shaved in this way, sputtering is carried out, while the magnet devices 1261 to 1264 are being moved in areas inside the outer peripheries of the sputtering surfaces of the targets 1211 to 1214.
A part of SiO2 flicked out from the sputtering surfaces of the targets 1211 to 1214 adheres onto the surface of the substrate 131 to form a thin film of SiO2 on the surface of the substrate 131.
At such time, a part of SiO2 flicked out from the targets 1211 to 1214 adheres onto the surfaces of the adhesion-preventing members 1251 to 1254. There was a problem that the thin films of the adhesion material adhered onto the surfaces of the adhesion-preventing members 1251 to 1254 peel off from the surface of the adhesion-preventing members 1251 to 1254 during the sputtering, and scatter inside the vacuum chamber 111, so that abnormal electric discharge (arcing) is induced and the thin film formed on surface of the substrate 131 is contaminated.
Not only in the case where the insulative SiO2 thin film is formed on the surface of the substrate 131, as explained above, but also in the case where an electroconductive thin film of a metal is formed, there was a problem in that thin films of adhesion material adhered onto the surfaces of the adhesion-preventing members 1251 to 1254 were peeled off from the adhesion-preventing members 1251 to 1254 during the film formation and the thin film formed on the surface of the substrate 131 was contaminated.
The present invention was created to solve the disadvantages of the above-mentioned prior art; and objects thereof is to provide an adhesion-preventing member from which a thin film of an adhesion material is not peeled off during a film deposition process, and to provide a sputter deposition apparatus having such adhesion-preventing member.
The present invention is to solve the above-mentioned problems, and is a sputter deposition apparatus for forming a film on a film deposition surface of a substrate arranged at a position facing a sputtering surface of a target, said sputter deposition apparatus comprising: a vacuum chamber; a vacuum evacuation device evacuating the inside of the vacuum chamber; a gas introduction system introducing a gas into the vacuum chamber; a target having a sputtering surface exposed inside the vacuum chamber; an electric power supply for applying a voltage to the target; and an adhesion-preventing member arranged at a position in which sputtered particles sputtered from the sputtering surface of the target are to be attached, wherein the adhesion-preventing member comprises Al2O3, and an arithmetically average roughness of that adhering face of a surface of the adhesion-preventing member to which the sputtered particles are attached is at least 4 μm to at most 10 μm.
The present invention is the sputter deposition apparatus, wherein the adhesion-preventing member comprises a target-side adhesion-preventing member arranged for the target such that the target-side adhesion-preventing member surrounds the sputtering surface of the target.
The present invention is the sputter deposition apparatus, wherein the target comprises a plurality of targets, the targets are arranged in a line spaced apart from each other inside the vacuum chamber, the sputtering surfaces of the targets are arranged to be positioned on the same plane, and the electric power supply applies an alternative voltage between two adjacent targets, and wherein a gap between an outer periphery of the sputtering surface of one of the two adjacent targets and an outer periphery of the sputtering surface of the other target is covered with the target-side adhesion-preventing member.
The present invention is the sputter deposition apparatus, wherein the target comprises a plurality of targets, the targets are arranged in a line spaced apart from each other inside the vacuum chamber, sputtering surfaces of the targets are arranged to be positioned on the same plane, and the electric power supply applies either a DC voltage or an AC voltage between each of the targets and a substrate arranged at a position facing the sputtering surface of the target, and wherein a gap between an outer periphery of the sputtering surface of one of the two adjacent targets and the sputtering surface of the other target is covered with the target-side adhesion-preventing member.
The present invention is the above-described sputter deposition apparatus, wherein the adhesion-preventing member comprises a target-side adhesion-preventing member arranged for the substrate such that the target-side adhesion-preventing member surrounds a periphery of the film-forming surface of the substrate.
The present invention is the above-described sputter deposition apparatus, wherein the target comprises SiO2.
The present invention is the above-described sputter deposition apparatus, wherein the target comprises Si, and the gas introduction system is O2 gas source for discharging the O2 gas.
The present invention is the adhesion-preventing member which is arranged at that position in a film deposition apparatus to which film deposition particles are to be attached, the film deposition apparatus comprising: a vacuum chamber; a vacuum evacuating device evacuating the inside of the vacuum chamber; and a unit for discharging film deposition particles from a film deposition materials arranged inside the vacuum chamber, wherein the adhesion-preventing member comprises Al2O3, and an arithmetically average roughness of that adhering face of the surface of the adhesion-preventing member to which the sputtered particles are to be attached is set at between at least 4 μm and at most 10 μm.
The present invention is the adhesion-preventing member which is arranged at that position in an film deposition apparatus to which film deposition particles are attached, wherein the film deposition apparatus comprising: a vacuum chamber; a vacuum evacuating device evacuating the inside of the vacuum chamber; a gas introduction system introducing a gas into the vacuum chamber; and a reacting unit producing the film deposition particles from a chemical reaction of the gas introduced into the vacuum chamber, wherein the adhesion-preventing member comprises Al2O3, and an arithmetically average roughness of that adhering surface on the surface of the adhesion-preventing member to which the sputtered particles are to be adhered is set at between at least 4 μm and at most 10 μm.
Note that the arithmetic average roughness (Ra) is prescribed in JIS B0601:2001.
Since a thin film on an adhesion material is not peeled off from the adhesion-preventing member, contamination of the thin film formed on the substrate by an adhesion materials on the thin film can be prevented; and thus, the quality of the thin film formed on the substrate can be improved.
Even if the adhesion material is insulative, because the adhesion-preventing member is also insulative, neither insulation breakdown nor arcing occurs on the thin film of the adhesion material. Therefore, the adhesion-preventing member can be prevented from being damaged by the arcing; and it is possible to prevent the contamination of the thin film formed on the substrate caused by impurities originating from the arcing.
The structure of a first embodiment of the sputter deposition apparatus of the present invention will now be explained.
The sputter deposition apparatus 10 includes a vacuum chamber 11, and a plurality of sputter units 201 to 204. The structure of the sputtering units 201 to 204 includes targets 211 to 214 having sputtering surfaces 231 to 234 exposed inside the vacuum chamber 11, and the targets 211 to 214 arranged on the surfaces of the backing plates 221 to 224, and magnet devices 261 to 264.
The structure of each of the sputtering units 201 to 204 is the same; and thus, the structural arrangement of the sputtering unit 201 will be explained as a representative example of the sputter units.
The target 211 is formed into a flat planar shape with a surface which is smaller than the surface of a backing plate 221; the entire outer periphery of the target 211 is positioned on the inside of the outer periphery of the backing plate 221; and the target 211 is stacked upon and affixed to the surface of the backing plate 221 in a manner such that the entire peripheral edge of the backing plate 221 is exposed from the outer periphery of the target 211. The target 211 and the backing plate 221 having a surface affixed to the target 211 is hereinafter referred to as a target unit.
A magnet device 261 includes an outer peripheral magnet 27a1, a center magnet 27b1, and a magnet fixing plate 27c1. In this embodiment, the center magnet 27b1 is linearly arranged on a surface of the magnet fixing plate 27c1, and the outer peripheral magnet 27a1 annularly surrounds the center magnet 27b1 on the surface of the magnet fixing plate 27c1, while being separated from the peripheral edge of the center magnet 27b1 by a predetermined distance.
In other words, the outer peripheral magnet 27a1 is formed in a ring shape, and the center magnet 27b1 is arranged inside the ring of the outer peripheral magnet 27a1. The “ring shape” as used here refers to a shape surrounding the periphery of the center magnet 27b1, and does not necessarily mean one seamless circular ring. In other words, as long as it surrounds the periphery of the center magnet 27b1, and the ring may have plurality of parts and have linear shape at a certain portion thereof. Moreover, a closed circular ring or a closed and deformed circular ring may be employed.
A magnet device 261 is arranged on a rear surface side of the backing plate 221. As to a magnet fixing plate 27c1 of the magnet device 261, its surface on which the center magnet 27b1 and the outer peripheral magnet 27a1 are arranged to face the rear surface of the backing plate 221. Different magnetic polarities from each other are arranged respectively at a portion of the outer peripheral magnet 27a1 facing the rear surface of the backing plate 221 and a portion of the center magnet 27b1 facing the rear surface of the backing plate 221.
In other words, the magnet device 261 comprises a center magnet 27b1 arranged in a direction in which a magnetic field is generated on the sputtering surface 231, and an outer peripheral magnet 27a1 arranged so as to be in a continuous shape around the center magnet 27b1. The center magnet 27b1 and the outer peripheral magnet 27a1 are arranged in such a manner that magnetic poles having different polarities from each other face the sputtering surface 231. That is, the magnetic polarities of the magnetic pole of that portion of the outer peripheral magnet 27a1 which faces the rear surface of the target 211 and the magnetic polarities of the magnetic pole of that portion of the center magnet 27b1 which faces the rear surface of the target 211 are different from each other.
A moving device 29 as an XY stage is arranged on a rear surface side of the magnet fixing plate 27c1; and the magnet device 261 is fixed to the moving device 29. A control unit 36 is connected to the moving device 29; and the transfer device 29 is constructed to transfer the magnet device 261 in a direction parallel to the rear surface of the target 211 upon receipt of a control signal from the control unit 36.
When the magnet device 261 is moved by the moving device 29, a magnetic field formed on the target 211 by the magnet device 261 moves on the surface of the target 211 accompanied with the movement of the magnet device 261.
The overall structure of the sputter deposition apparatus 10 will now be explained. For an exhaust opening and an introduction inlet of the vacuum chamber 11, a vacuum evacuation device 12 is connected to the exhaust opening, and a gas introducing system 13 is connected to the introduction inlet. The vacuum evacuation device 12 is constructed to evacuate the inside of the vacuum chamber 11 through the exhaust opening. The gas introduction system 13 has a sputtering gas source 13a for discharging a sputtering gas and a reactive gas source 13b for discharging a reactive gas and reactable with the targets 211 to 214 in the respective sputter units 201 to 204 so that a mixed gas of the sputtering gas and the reactive gas can be introduced into the vacuum chamber 11 through the introduction inlet.
The target portions in the respective sputter units 201 to 204 are arranged in a line inside the vacuum chamber 11, while being separated from one another; and the surfaces of the targets 211 to 214 of the respective target portions are aligned to be positioned in the same plane.
The backing plates 221 to 224 of the sputter units 201 to 204 are attached to a wall surface of the vacuum chamber 11 via columnar insulating materials 14; and the backing plates 221 to 224 of the sputter units 201 to 204 are electrically insulated from the vacuum chamber 11.
An electric power supply 37 is electrically connected to the backing plates 221 to 224 in the respective sputter units 201 to 204. The electric power supply 37 is constructed to apply an AC voltage to the backing plates 221 to 224 of the sputter units 201 to 204, while shifted between two adjacent targets by a half cycle. When AC voltage having opposite polarities from each other is applied to the two adjacent targets, one of the two adjacent targets is set to a positive potential, and the other target is set to a negative potential; consequently, an electric discharge is generated between the adjacent targets. The frequency of the AC voltage is preferably 20 kHz to 70 kHz (that is, between at least 20 kHz and at most 70 kHz) because the electric discharge can be stabilized and maintained between the adjacent targets, and is, preferably, 55 kHz.
The electric power supply 37 of the present invention is not only constructed to apply the AC voltage to the backing plates 221 to 224 in the sputter units 201 to 204, but also may be constructed to apply pulse-like negative voltages thereto for more than once. In this case, after the application of the negative voltage is finished and before starting to apply the negative voltage to one of the two adjacent targets, the negative voltage is applied to the other of the two adjacent targets.
The sputter deposition apparatus 10 includes adhesion-preventing members positioned to the place where sputtered particles discharged by sputtering from sputtering surfaces 231 to 234 of the targets 211 to 214 are adhered.
The adhesion-preventing members comprise target-side adhesion-preventing members 251 to 254 positioned on the targets 211 to 214 in such manner that they surround the peripheries of the sputtering surfaces 231 to 234 of the targets 211 to 214.
In other words, the ring-shaped target-side adhesion-preventing members 251 to 254 are positioned outside of the outer peripheries of the respective targets 211 to 214. The “ring shape” as used here refers to a shape surrounding the periphery of the sputtering surfaces 231 to 234 of the targets 211 to 214, and does not necessarily mean one seamless circular ring. In other words, as long as it surrounds the periphery of the sputtering surfaces 231 to 234 of the targets 211 to 214, and the ring may have plurality of parts and have a linear shape at a certain portion thereof.
The target-side adhesion-preventing members 251 to 254 comprise Al2O3; and the arithmetically average roughness of those faces (hereinafter referred to as adhering surfaces or faces) of the surfaces of the target-side adhesion-preventing members 251 to 254, which are exposed to the outer sides of the outer peripheries of the sputtering surfaces 231 to 234 of the targets 211 to 214, is set to between at least 4 μm and at most 10 μm. As shown by the Examples, as discussed below, the adhering surfaces of the target-side adhesion-preventing members 251 to 254 having the arithmetically average roughness of between at least 6 μm and at most 10 μm is the most preferable.
The structural arrangements of the sputter units 201 to 204 are the same; and thus, the sputter unit 201 will be explained as a representative example. As shown in
The target-side adhesion-preventing member 251 is arranged on a surface of the backing plate 221 to which the target 211 is fixed at such a relative position that the center of the ring of the target-side adhesion-preventing member 251 overlaps with the center of the target 211; and the target-side adhesion-preventing member covers that peripheral edge portion of the backing plate 221 which is exposed from outer periphery of the target 211, so that the inner periphery of the target-side adhesion-preventing member 251 surrounds the outer periphery of the target 211.
The inner periphery of the ring is preferably as small as possible should the below-mentioned plasma enter a gap between the inner periphery of the ring of the target-side adhesion-preventing member 251 and the outer periphery of the target 211.
The entire surface of the target 211 is exposed to inside of the ring of the target-side adhesion-preventing member 251, so that the entire front surface of the target 211 constitutes the sputtering surface to be sputtered. A reference numeral 231 denotes the sputtering surface.
When the sputtering surface 231 of the target 211 is sputtered as explained later, a portion of particles discharged from the sputtering surface 231 are adhered to the adhesion surface of the target-side adhesion-preventing member 251; therefore, the particles do not adhere to the surface of the backing plate 221.
The target-side adhesion member 251 in the present invention is not limited to the case in which the inner periphery of the ring of the target-side adhesion-preventing member 251 is the same as or larger than the outer periphery of the target 211, but it includes a case in which the inner periphery of the ring of the target-side adhesion-preventing member 251 is smaller than the outer periphery of the target 211. In this case, when the target-side adhesion-preventing member 251 is arranged on the surface of the target 211 as explained above, the target-side adhesion-preventing member 251 covers the peripheral portion of the target 211; and thus, the portion of the surface of the target 211 which is exposed from the inside of the ring of the target-side adhesion-preventing member 251 becomes the sputtering surface 231 to be sputtered.
In other words, the target-side adhesion-preventing member 251 is set at that edge portion of the target 211 where the face side of the surface of the target 211 which includes the sputtering surface 231 becomes discontinuous, and surrounds the periphery of the sputtering surface 231.
As far as the relationship between the one putter unit (for example, a reference numeral 201) among the sputtering units 201 to 204 and another sputtering unit 202 adjacent thereto is concerned, the gap between the outer periphery of the sputtering surface 231 of one target 211 of the two adjacent targets 211, 212 and the outer periphery of the sputtering surface 232 of the other target 212 is covered with the target-side adhesion-preventing members 251, 252.
Therefore, the sputtered particles discharged from the respective sputtering surfaces 231 and 232 do not permeat the gap between the outer periphery of the sputtering surface 231 of one target 211 and the outer periphery of the sputtering surface 232 of the other target 212.
Columnar supporting members 24 are erected outside of the outer peripheries of the backing plates 221 to 224, and the target-side adhesion-preventing members 251 to 254 are attached on the tips of the supporting members 24.
When the supporting member 24 is electroconductive, the supporting member 24 is spaced from the outer periphery of the backing plate 221. The electroconductive supporting member 24 is electrically connected to the vacuum chamber 11. However, the target-side adhesion-preventing member 251 is electrically insulative; therefore, the backing plate 221 is electrically insulated from the vacuum chamber 11, even though the target-side adhesion-preventing member 251 contacts the backing plate 221.
Furthermore, when the supporting member 24 is either electroconductive or electrically insulative, the target-side adhesion-preventing members 251 to 254 are electrically floating.
The sputter deposition apparatus 10 includes a substrate holding plate 32 for holding the substrate 31.
When the substrate 31 is held by the substrate holding plate 32, the substrate 31 is positioned in such a manner that it faces the surfaces of the respective targets 211 to 214 (the sputtering surfaces 231 to 234). The size of the surface of the substrate holding plate 32 is made larger compared to the size of the surface of the substrate 31, so that the entire outer periphery of the substrate 31 is positioned inside of the outer periphery of the substrate holding plate 32; and the substrate 31 is held at the surface of the substrate holding plate 32 at such a relative position, so that the entire periphery of the peripheral edge portion of the substrate holding plate 32 is exposed from the outer periphery of the substrate 31.
The surface of the substrate 31 on which a film is to be deposited is exposed inside the vacuum chamber 11.
Here, the adhesion-preventing member comprises a substrate-side adhesion-preventing member 35 which is arranged on the substrate 31 in such a manner that surrounds the periphery of the deposition surface of the substrate 31.
In other words, the ring-shaped substrate-side adhesion-preventing member 35 is arranged on the outer side of the outer periphery of the substrate 31. The “ring shape” as used here refers to a shape surrounding the periphery of the deposition surface of the substrate 31, and does not necessarily mean one seamless circular ring. In other words, as long as it surrounds the periphery of the deposition surface of the substrate 31, the ring may have a plurality of parts and have linear shape at a certain portion thereof.
The substrate-side adhesion-preventing member 35 comprises Al2O3, and the arithmetic average roughness of the face (hereinafter referred to as adhering surface) of the surface of the substrate-side adhesion-preventing member 35, which is exposed outside of the outer periphery of the film forming surface of the substrate 31, is set at between at least 4 μm and at most 10 μm. As explained later by way of the Examples, the arithmetic average roughness of that adhering surface of the substrate-side adhesion-preventing member 35 is the most preferable when set at between at least 6 μm and at most 10 μm.
The outer periphery of the ring of the substrate-side adhesion-preventing member 35 is larger than the outer periphery of the substrate holding plate 32, whereas the inner periphery of the substrate-side adhesion-preventing member 35 is the same or larger than the outer periphery of the film deposited face of the surface of the substrate 31 on which a film is deposited.
The substrate-side adhesion-preventing member 35 is positioned on the surface of the substrate holding plate 32 for holding the substrate 31 at such a relative position that the center of the ring of the substrate-side adhesion-preventing member 35 overlaps with that of the film forming surface of the substrate 31; and the substrate-side adhesion-preventing member covers the peripheral portion of the substrate holding plate 32 exposed from the outer periphery of the substrate 31, and surrounds the outer periphery of the film forming surface of the substrate 31 with the inner periphery of the ring of the substrate-side adhesion-preventing member 35.
As explained later, when the sputtering surfaces 231 to 234 of the respective targets 211 to 214 are sputtered, a part of the particles discharged from the respective sputtering surfaces 231 to 234 are adhered onto the surface of the substrate 31 and the adhering surface of the substrate-side adhesion-preventing member 35, respectively, but not adhered onto the surface of the substrate holding plate 32.
Hereinafter, the substrate 31, the substrate holding plate 32 for holding the substrate 31 and the substrate-side holding member 35 surrounding the outer periphery of the film forming surface of the substrate 31 are referred to as an object to be processed 30.
A method for sputter deposition of a SiO2 thin film on the film deposition surface of the substrate 31 by using the sputter deposition apparatus 10 will be explained.
First, an explanation is made of a measuring step for determining the protruding minimum value as the minimum value and the protruding maximum value as the maximum value of a distance by which a portion of the outer peripheries of the outer peripheral magnets of the magnet device 261 to 264 in the sputter units 201 to 204 protrude from the outer peripheries of the sputtering surfaces 231 to 234 of the target 211 to 214 in the sputter units 201 to 204.
In reference to
The target-side adhesion-preventing members 251 to 254 are fixed to the supporting members 24, and the sputtering surfaces 231 to 234 of the targets 211 to 214 of the sputtering portions 201 to 204 are exposed on the inside of the rings of the target-side adhesion-preventing members 251 to 254.
The inside of the vacuum chamber 11 is evacuated by the vacuum evacuating device 12. Afterward, the vacuum ambience inside the vacuum chamber 11 is maintained by continuous vacuum evacuation.
While the object to be processed 30 is not carried into the vacuum chamber 11, the gas introduction system 13 introduces the mixed gas of the sputtering gas and the reactive gas. Here, Ar gas is used as the sputtering gas, and O2 gas is used as the reactive gas, whereas the mixed gas is introduced into the vacuum chamber 11 at such a flow rate which makes a so-called Oxide Mode in which the O2 gas introduced from the reactive gas source 13b(O2 gas source) into the vacuum chamber 11 reacts with the surfaces of the targets 211 to 214 of the sputter units 201 to 204, and an electrically insulative oxide SiO2 is formed on the surfaces on the targets 211 to 214. Here, Ar gas is introduced at a flow rate of 50 sccm and the O2 gas is introduced at a flow rate of 150 sccm.
The vacuum chamber 11 is set at a ground potential. When AC voltages of 20 kHz to 70 kHz are applied from the electric power supply 37 to the backing plates 221 to 224 of the sputter units 201 to 204, an electric discharge is generated between the adjacent targets 211 to 214, and Ar gas above the targets 211 to 214 in the sputter units 201 to 204 is ionized and then plasmatized.
Ar ions in the plasma are trapped in a magnetic fields formed by the magnet devices 261 to 264 of the sputter units 201 to 204. When a negative voltage is applied to the backing plates 221 to 224 of the sputter units 201 to 204 from the electric power supply 37, the Ar ions collide against the sputtering surfaces 231 to 234 of the targets 211 to 214 on the backing plates 221 to 224 to which the negative voltage is applied, and SiO2 particles formed on the sputtering surfaces 231 to 234 are stricken off. The state of the sputter units 201 to 204 during the sputtering is the same, so the following explanation uses the sputter unit associated with reference numeral 201 as a representative example.
While moving the magnet device 261 by the moving device 29, the magnetic field formed above the surface of the target 211 by the magnet device 261 moves above the surface of the target 211 together with the plasma trapped in the magnetic field, and the surface of the target 211 is continuously sputtered along a movement trajectory of the plasma.
When the magnet device 261 is moved in a movement area in which the entire outer periphery of the outer peripheral magnet 27a1 is located inside the outer periphery of the sputtering surface 231, a central portion of the sputtering surface 231 is sputtered and shaved in a concaved form. The area of the sputtering surface 231 which is shaved by sputtering is referred as an erosion area. The sputtering surface 231 is shaved to the point where the location of the outer peripheral of the erosion area is visually recognized.
Next, the composition and the pressure of the gas evacuated under vacuum from the inside of the vacuum chamber 11 are being monitored as the movement area of the magnet device 261 is gradually widened, and the amount by which a portion of the outer periphery of the outer peripheral magnet 27a1 protruded to the outside of the outer periphery of the sputtering surface 231 is gradually increased.
As the amount of the portion of the outer periphery of the outer peripheral magnet 27a1 which protrudes to the outside of the outer periphery of the sputtering surface 231 increases, the horizontal component of the magnetic field on the target-side adhesion-preventing member 251 increases; and when the target-side adhesion-preventing member 251 is shaved by sputtering, the gas composition inside the vacuum chamber 11 changes during the evacuation. When the sputtering of the adhesion-preventing member 251 has been confirmed by the change in the gas composition during the evacuation based on the change in the gas composition in the vacuum chamber 11, the amount of protrusion of the outer periphery of the outer peripheral magnet 27a1 from the outer periphery of the sputtering surface 231 is measured.
In a producing step to be explained later, if the target-side adhesion-preventing member 251 is shaved by sputtering, the particles from the target-side adhesion-preventing member 251 adhere to the surface of the substrate 31, and a film formed on the surface of the substrate 31 becomes contaminated with impurities. Accordingly, the amount of protrusion measured here is stored in the control unit 36 as the maximum protruding value.
In the case where the degree of the hardness of the target-side adhesion-preventing member 251 is so high that it cannot be sputtered (i.e., when a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes to the inside of the sputtering surface 232 of the adjacent target 212, and the sputtering surface 232 of the adjacent target 212 is shaved), the pressure inside the vacuum chamber 11 changes. When the sputtering of the sputtering surface 232 of the adjacent target 212 has been confirmed from the change in pressure inside the vacuum chamber 11, the amount of protrusion of the outer periphery of the outer peripheral magnet 27a1 from the outer periphery of the sputtering surface 231 is measured.
In a producing step to be explained later, if the sputtering surface 232 of the target 212 in the sputter unit 202 is shaved by the plasma trapped in the magnetic field of the magnet device 261 in the adjacent sputter unit 201, the flatness of a thin film formed on the surface of the substrate 31 is deteriorated; therefore, the amount of protrusion measured here is stored in the control unit 36 as the maximum protruding value.
Next, in reference to
The target-side adhesion-preventing member 251 to 254 of the sputter units 201 to 204 are removed from the supporting members 24; and the target portions of the sputter units 201 to 204 are carried to the outside of the vacuum chamber 11.
The size of the gap between the outer periphery of the erosion area and the outer periphery of the sputtering surface 231 is measured from the target 211 of the target portion carried to the outside of the vacuum chamber 11. It is understood that as the inside of the above described distance from the outer periphery of the outer peripheral magnet 27a1 is shaved by sputtering, the size of the gap measured here is stored in the control unit 36 as the minimum protruding value.
Next, in reference to
The target-side adhesion-preventing members 251 to 254 are fixed to the supporting members 24, and the sputtering surfaces 231 to 234 of the targets 211 to 214 of the sputter units 201 to 204 are exposed inside the rings of the target-side adhesion-preventing members 251 to 254.
The inside of the vacuum chamber 11 is evacuated by the vacuum evacuation device 12. Consequently, the vacuum ambience is maintained inside the vacuum chamber 11 by continuous evacuation.
The object to be processed 30 is carried into the inside of the vacuum chamber 11, and is then stopped at a position where the film deposition surface of the substrate 31 on the object to be processed 30 faces the sputtering surfaces 231 to 234 of the targets 211 to 214 of the sputter units 201 to 204.
The mixed gas of the sputtering gas and the reactive gas is introduced from the gas introduction system 13 into the vacuum chamber 11 at the same flow rates as in the above described measuring step. The surfaces of targets 211 to 214 of the sputter units 201 to 204 react with the O2 gas introduced into the vacuum chamber 11 as the reactive gas; and thus, SiO2 is formed.
Similar to the measuring step, the AC voltage is applied to the backing plates 221 to 224 of the sputter units 201 to 204 from the electric power supply 37; and the Ar gas between the targets 211 to 214 of the sputter units 201 to 204 and the substrate 31 is plasmatized to sputter the sputtering surfaces 231 to 234 of the targets 211 to 214 of the sputter units 201 to 204.
A portion of SiO2 particles sputtered from the sputtering surfaces 231 to 234 of the targets 211 to 214 of the sputter units 201 to 204 adheres to the film deposition surface of the substrate 31; and thus, the thin film of SiO2 is formed on the film deposition surface of the substrate 31.
A portion of the SiO2 particles sputtered from the sputtering surfaces 231 to 234 of the targets 211 to 214 adheres to the adhering surfaces of the target-side adhesion-preventing members 251 to 254 and the adhering surface of the substrate-side adhesion-preventing member 35. The target-side adhesion-preventing members 251 to 254 and the substrate-side adhesion-preventing members 35 both comprise Al2O3, and the arithmetically average roughness of the adhering surfaces of the target-side adhesion-preventing members 251 to 254 and the arithmetically average roughness of the adhering surfaces of the substrate-side adhesion-preventing member 35 are both set at between at least 4 μm and at most 10 μm; and as explained later in the Examples below, the thin films of the attached material adhered to the adhering surfaces of the adhesion-preventing members 251 to 254 and 35 during the sputtering are not peeled off from the adhering surfaces. Thus, a problem (such as, the thin film on the adhered material peeled off from the adhering surfaces of the adhesion-preventing members 251 to 254, and 35 scatter inside the vacuum chamber 11 to induce arcing, or adhere to the surface of the substrate 31 to contaminate the thin film formed on the deposition surface of the substrate 31) does not occur.
Further, since the target-side adhesion-preventing members 251 to 254 are insulative, no insulation breakdown occurs on the adhered films of SiO2 deposited on the adhering surfaces of the target-side adhesion-preventing members 251 to 254, and no arcing occurs above the target-side adhesion-preventing members 251 to 254. Since no arcing occurs above the target-side adhesion-preventing members 251 to 254, damage to the target-side adhesion-preventing members 251 to 254 due to the arcing can be prevented. Also, the contamination of the thin film formed on the film forming surface of the substrate 31 by impurities originating from the arcing can be prevented.
The state of the sputter units 201 to 204 during the sputtering is the same. Therefore, the following explanation uses the sputter unit associated with reference numeral 201 as a representative example.
Here, the control unit 36 is constructed to move the magnet device 261 between a position in which the entire outer periphery of the outer peripheral magnet 27a1 is positioned inside the outer periphery of the sputtering surface 231 of the target 211; and a position in which a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes from the outer periphery of the sputtering surface 231.
In other words, the magnet device 261 is constructed to move between a position in which the entire outer periphery of the outer periphery magnet 27a1 is included inside the inner periphery of the adhesion-preventing member 251 that surrounds the periphery of the sputtering surface 231 and a position in which a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes outside from the inner periphery of the adhesion-preventing member 251 that surrounds the periphery of the sputtering surface 231.
When a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes from the outer periphery of the sputtering surface 231 during the sputtering, the plasma trapped in the magnetic field of the magnet device 261 contacts the target-side adhesion-preventing member 251; however, since the target-side adhesion-preventing member 25a1 is made of an electrically insulated material, no arcing occurs when the plasma contacts the target-side adhesion-preventing member 251. Therefore, when compared to the prior art, a preferable wider area of the sputtering surface 231 of the target 211 can be sputtered.
The control unit 36 of the present invention is not limited to the above construction, but the control unit may be constructed to make the magnet device 261 move in an area where the entire outer periphery of the outer peripheral magnet 27a1 is included inside of the outer periphery of the sputtering surface 231 of the target 211. However, it is preferable to have a case where a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes outside the outer periphery of the sputtering surface 231, and a case where a wider area of the sputtering surface 231 can be sputtered.
Here, the control unit 36 makes a portion of the outer periphery of the outer peripheral magnet 27a2 protrude from the outer periphery of the sputtering surface 231 by a distance longer than the minimum protruding value determined in the measuring step; and while the magnet device 261 is being moved, and when the members such as, backing plate 221 or the like, between the target 211 and the magnet device 261 are ignored, the magnet device 261 which the surface facing the rear side surface of the target 211 of the outer peripheral magnet 27a1 does not pass the position that is right on back of the same portion of the sputtering surface 231 of the target 211, but the surface of the outer peripheral magnet 27a1 facing the rear side surface of the target 211 is made to move to pass everywhere on the right on back of the entire sputtering surface 231 of the target 211.
Moreover, when the outer peripheral magnet 27a1 protrudes to the outer periphery of the sputtering surface 231, it does not protrude from the same portion of the outer periphery, and the magnet device 261 is made to move so that the outer peripheral magnet 27a1 protrudes at least once from every portion of the outer periphery of the sputtering surface 231.
Consequently, the entire sputtering surface 231 inside the outer periphery is shaved by sputtering, and SiO2 re-adhering on the sputtering surface 231 is not deposited on the sputtering surface 231. Since insulative SiO2 is deposited on the surface of the electroconductive target in the prior art, arcing occurs on the target due to the insulation breakdown of the deposited SiO2; however, with respect to the present invention, SiO2 is not deposited on the target 211; thus, no arcing occurs on the target 211.
The target 211 can be prevented from being damaged from the arcing because no arcing occurs on the target 211. Also, the thin film formed on the substrate 31 can be prevented from being contaminated by impurities.
Furthermore, the control unit 36 is constructed to make the outer periphery of the outer peripheral magnet 27a1 protrude from the outer periphery of the sputtering surface 231 by a distance smaller than the maximum protrusion value determined in the measuring step. Therefore, the target-side adhesion-preventing member 251 can be prevented from being shaved by sputtering; and the contamination of the thin film formed on the substrate 31 by impurities can be prevented.
As to the relationship between one of the sputter units 201 to 204 (for example, the sputter unit 201) and another sputter unit 202 adjacent thereto, the control unit 36 is constructed to make the magnet device 261 in the one sputter unit 201 to move between a position where the entire outer periphery of the outer peripheral magnet 27a1 of the magnet device 261 is included in a place inside the outer periphery of the sputtering surface 231 of the target 211 in the sputter unit 201, and to also move from a position where a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes to the outer periphery of the sputtering surface 231 to the outer periphery of the sputtering surface 232 of the target 212 of another sputter unit 202 which is adjacent to the target 211.
In other words, when an area between the outer periphery of the sputtering surface 231 of the target 211 in one sputter unit 201 and the outer periphery of the sputtering surface 232 of the target 212 in another sputter unit 202 adjacent to the sputter unit 201 is referred as an outer area, the control unit 36 is constructed to make the magnet device 261 in the sputter unit 201 move between the position where the entire outer periphery of the outer peripheral magnet 27a1 of the magnet device 261 is included inside the outer periphery of the sputtering surface 231 of the target 211 in the sputter unit 201 and the position where the entire outer periphery of the outer peripheral magnet 27a1 of the magnet device 261 protrudes into the outer area.
In other words, the magnet device 261 arranged on a back side of the sputtering face 231 of at least one target 211 is constructed to move between the position in which the entire outer periphery of the outer peripheral magnet 27a1 is included inside the inner periphery of the adhesion-preventing member 251 surrounding the periphery of the sputtering surface 231 of the target 211 and the position where a portion of the outer periphery of the outer peripheral magnet 27a1 protrudes between the outer side of the inner periphery of the adhesion-preventing member 251 of the target 211 and the inner periphery of the adhesion-preventing member 252 surrounding the periphery of the sputtering surface 232 of another target 212 adjacent to the target 211.
Therefore, regarding the present invention, if the size of the sputtering surface 231 to 234 of the targets 211 to 214 of the sputter units 201 to 204 are the same as in the prior art and the distance between the outer periphery of the sputtering erosion area of the sputtering surface 231 of the target 211 in one sputter unit (here, reference numeral 201) and the outer periphery of the erosion area of the sputtering surface 232 of the target 212 in another sputter unit 202 adjacent thereto is also set the same as in the prior art, the distance of the gap between the outer peripheries of the adjacent targets 211 to 214 can be made wider compared to the prior art. Therefore, the amount of the target material used can be reduced and the reduction in cost can be attained.
In reference to
The object to be processed 30 that have undergone the treatment is carried to the outside of the vacuum chamber 11, and sent to a succeeding step. Then, an unprocessed object to be processed 30 is carried into the inside of the vacuum chamber 11, and the above explained producing step of the sputtering film deposition is repeated.
In the above description, the case in which the sputter deposition apparatus 10 is equipped with a plurality of the sputter units has been explained, but the present invention can include a case with only one sputter unit. In this case, an electric power supply is electrically connected to a backing plate and a substrate holder, an AC voltages having opposite polarities from each other are applied to a target and a substrate, an electric discharge is generated between the target and the substrate, and it is enough to plasmatize the sputtering gas between the target and the substrate.
In the above explanation, the target of the sputter units and the substrates are in the state where they are standing and are facing towards each other. However, the present invention is not limited to such a structural arrangement as long as the sputtering surface of the target of the sputter units and the film deposition surface of the substrate are faced toward each other (that is, that they can face each other by arranging the substrate above the target of each sputter units, and they face each other by arranging the substrate below the target of each sputter unit). If the substrate is arranged under the target in each of the sputter units, particles may fall onto the substrate causing the quality of the thin film to deteriorate. Therefore, it is preferable to arrange the substrate above the target of each sputter units, or as explained above, to arrange the substrate and the target of each sputter unit to face each other in a state where they are standing.
In
In the above explanation, at first, the O2 gas is reacted with the surfaces of the targets 211 to 214 of Si to form SiO2 on the surface of the targets 211 to 214; and then, the thin film of SiO2 is formed by sputtering the surfaces of the targets 211 to 214. However, the present invention also includes a case such that by sputtering the surfaces of Si 211 to 214 without O2 gas being reacted with the targets 211 to 214, Si particles are discharged from the surfaces of the targets 211 to 214 and are reacted with O2 gas to form a thin film of SiO2.
In the above explanation, a case in which the thin film of SiO2 is formed by sputtering the Si target while O2 gas is introduced into the vacuum chamber 11; however, a case in which a thin film of SiO2 is formed by sputtering a SiO2 target is also included in the present invention.
Furthermore, the present invention can be used in a case in which a target of a metallic material (such as, Al or the like) is sputtered to form a metallic thin film.
Also, if O2 gas is not used in the deposition of the film, the O2 gas source 13b may be omitted from the gas introduction system 13 in the sputter deposition apparatus 10.
The adhesion-preventing member of the present invention is not limited to the target-side adhesion-preventing members 251 to 254 arranged at the positions surrounding the outer peripheries of the sputtering surfaces 231 to 234 of the targets 211 to 214 and the substrate-side adhesion-preventing member 35 arranged at the position surrounding the outer periphery of the film forming surface of the substrate 31, as long as the adhesion-preventing member is at a position where the sputtered particles discharged from the sputtering surfaces 231 to 234 of the targets 211 to 214 by sputtering are adhered. For example, the present invention may have an adhesion-preventing member arranged on an inner wall surface of the vacuum chamber 11. Reference numeral 39 denotes the adhesion-preventing member arranged on the inner wall surface of the vacuum chamber 11.
In the case where the material of the inner wall surface of the vacuum chamber 11 is Al2O3, the inner wall surface of the vacuum chamber 11 itself may be used, after being treated to the arithmetically average roughness of at least 4 μm to at most 10 μm without the adhesion-preventing member 39 being attached to the inner wall surface of the vacuum chamber 11. However, it is much more preferable if the adhesion-preventing member 39 is attached to the inner wall surface because the cleaning of the vacuum chamber 11 is much easier.
The adhesion-preventing member regarding the present invention comprises Al2O3; and as long as the arithmetically average roughness of that adhering surface on the face of the adhesion-preventing member to which the film deposition particles are adhered to is set at between at least 4 μm and at most 10 μm, the adhesion-preventing member is not limited to those used in the sputter deposition apparatus as explained above. Moreover, in reference to
Here, discharging means is: in reference to
Moreover, the adhesion-preventing member of the present invention comprises Al2O3; and as long as the arithmetic average roughness of that adhering face on the surface of the adhesion-preventing member to which the film deposition particles are to be adhered is set at between at least 4 μm and at most 10 μm, in reference to
In reference to
As for the adhesion-preventing member with respect to the present invention, a material of all Al2O3 is much more preferable to a material with Al2O3 coated on the surface of the metallic body. Because when using the material with Al2O3 coated on the surface of the metallic body, and when heated by the plasma, a metal having a higher thermal expansion rate than Al2O3, there is a risk of Al2O3 coating of the heat expanded metallic body to be peeled off.
A first test adhesion-preventing member: Al2O3 in which the arithmetically average roughness of an adhering surface is set at less than 2 μm by blast process; a second test adhesion-preventing member: Al2O3 in which the arithmetically average roughness of an adhering surface is set at between at least 2 μm and less than 3 μm by blast process; a third test adhesion-preventing member: Al2O3 in which the arithmetically average roughness of an adhering surface was set at between at least 4 μm and less than 6 μm by blast process; and a fourth test adhesion-preventing member: Al2O3 in which the arithmetically average roughness of an adhering surface is set at between at least 6 μm and at most 10 μm by blast process were made.
Regarding the sputter deposition apparatus 10 of the present invention, in a testing step, one adhesion-preventing member from the first to fourth test adhesion-preventing members 251 to 254, and 35 is used as a mixed gas of Ar gas and O2 gas introduced into the vacuum chamber 11, and by sputtering Si targets 211 to 214, SiO2 particles are adhered to the surfaces of the adhesion-preventing members 251 to 254, and 35. When the targets 211 to 214 are continuously sputtered until the thickness of thin film (SiO2 film) of an adhered material adhered to the adhering surfaces of the adhesion-preventing members 251 to 254, and 35 reach 1000 μm, the sputtering is stopped, the adhesion-preventing members 251 to 254, and 35 are carried to outside of the vacuum chamber 11, and adhered surfaces of the adhesion-preventing members 251 to 254, and 35 are photographed. The testing steps were repeated by using each of the first to fourth test adhesion-preventing members as the adhesion-preventing members 251 to 254, and 35.
Furthermore, it is previously known that when 10,000 of the substrates 31 are deposited with film from the sputter deposition apparatus 10 without exchanging the adhesion-preventing members 251 to 254, and 35, a SiO2 film with the film thickness of 1000 μm is deposited on the adhering surfaces of the adhesion-preventing members 251 to 254, and 35.
According to the above results, it is understood that when using Al2O3 with the arithmetically average roughness of the adhering surface set at between at least 4 μm and at most 10 μm by the blast process, no adhering material is peeled off from the adhering surface of the adhesion-preventing member, although 10,000 substrates are processed.
Furthermore, when the arithmetically average roughness of the adhering surface is set at between at least 6 μm and at most 10 μm, it is understood that the effect preventing the peeling off of the adhering material is much larger.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-138498 | Jun 2010 | JP | national |
This application is a continuation of International Application No. PCT/JP2011/063583, filed on Jun. 14, 2011, which claims priority to Japan Patent Application No. 2010-138498, filed on Jun. 17, 2010. The contents of the prior applications are herein incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2011/063583 | Jun 2011 | US |
| Child | 13716421 | US |
