JP4017219B2 - Sputtering equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sputtering apparatus used for forming a thin film on a substrate, and more particularly to a rotary sputtering apparatus capable of manufacturing a thin film device in which a plurality of types of thin films are deposited in a laminated state.
[0002]
[Prior art]
In recent years, as high-performance thin film devices such as magnetic heads and magnetic sensors have been improved, it has been required to form a thin film having a highly accurate film thickness and a high quality film using a sputtering phenomenon. Research and development of technologies for forming high-performance thin films are being actively conducted. In particular, research on artificial lattices that exhibit a giant magnetoresistance (GMR) effect has recently been actively conducted. For the formation of this artificial lattice, a sputtering apparatus capable of attaching a plurality of targets made of different materials is used. For example, a multilayer film in which a magnetic film and a nonmagnetic film are alternately laminated on a substrate is formed. Is done. In the manufacture of a thin film device using this artificial lattice, it is necessary to form an ultrathin film of several to several tens of kilometers. In forming this ultrathin film, high-precision film thickness control and high-quality film quality reproducibility are required. It is necessary to ensure.
[0003]
FIG. 4 is a longitudinal sectional view showing a conventional sputtering apparatus that is generally used in a film forming process of a thin film device using an artificial lattice. In the figure, a vacuum chamber 1 of an outer container is connected to a vacuum exhaust pump 7 through a vacuum exhaust port 2, an exhaust chamber 3 and a valve 4 opened on the side wall thereof, and the vacuum exhaust pump 7 is driven. By doing so, the inside is pulled into a high vacuum state. A process gas such as argon gas is introduced into the vacuum chamber 1 in a high vacuum state through a gas introduction pipe (not shown).
[0004]
Inside the vacuum chamber 1, a rotary table 8 is rotatably provided around a rotary shaft 9, and a plurality of substrates 10 to be deposited are arranged on a rotary circle on the mounting surface (upper surface) of the rotary table 8. It is attached. On the other hand, as the target 11 made of a sputtering material, a plurality of types made of different materials are used, and these targets 11 are arranged on the movement trajectory of the substrate 10 by the rotation of the turntable 8 so as to face each other from above.
[0005]
The sputtering apparatus applies a voltage to a plurality of targets 11 simultaneously or sequentially from a power supply unit (not shown) via an electrode 12 and a backing plate 13 in a process gas atmosphere inside the vacuum chamber 1. For example, argon plasma is generated and ions having high energy are incident on the target 11 to eject sputtered particles from the target 11 and deposit the sputtered particles on the substrate 10, thereby forming a thin film on the surface of the substrate 10. Form.
[0006]
[Problems to be solved by the invention]
However, in the sputtering apparatus configured as described above, the air in the vacuum chamber 1 is exhausted while flowing toward the vacuum exhaust port 2 provided on one side wall, as indicated by arrows in the figure. The pressure state during film formation in the vicinity of the target 11 varies, and due to this pressure variation, a difference occurs in the film formation state in the vicinity of each target 11 and a thin film device having a desired film thickness cannot be formed. There's a problem. Further, when a plurality of films are simultaneously formed by a plurality of targets 11, the flow of the process gas flowing from the vicinity of the target 11 on the side away from the exhaust chamber 3 (left side in the drawing) toward the exhaust chamber 3 is Since it intersects with the flow of the process gas from the vicinity of the other target 11, the film components of each of the plurality of targets 11 are mixed. As a result, there is also a problem that a desired high quality film characteristic cannot be obtained because a film component formed by another target 11 is mixed in a thin film formed by a certain target 11.
[0007]
Therefore, an object of the present invention is to provide a sputtering apparatus that can solve the above-described problems and can form a multilayer film having a predetermined film thickness and high-quality film quality.
[0008]
[Means for Solving the Problems]
To achieve the above object rotation, of the invention according to claim 1, in which the vacuum chamber is rotatably disposed within the vacuum chamber, mounted a plurality of substrates are arranged in the mounting position on the rotating disc A table, an electrode arranged on an arrangement circle corresponding to the rotation trajectory of the substrate, and individually holding a plurality of targets facing the substrate; a mounting position of the substrate in the vacuum chamber; and an arrangement of the electrodes An exhaust passage formed in the center of each of the installed circles ; The inside of the vacuum chamber is surrounded by an upper space surrounded by the upper surface of the rotary table and the inner peripheral wall of the vacuum chamber and the substrate and the target are disposed, and the lower surface of the rotary table and the inner peripheral wall of the vacuum chamber. And an exhaust passage in the upper space and an exhaust passage in the lower space are provided separately .
[0009]
In this sputtering apparatus, an exhaust passage is provided at the mounting position of each substrate and at the central portion of the arrangement circle of each target, so that any air containing gas in the vicinity of each target is in the central exhaust passage. Collected and exhausted. Therefore, the exhaust paths from the vicinity of each target to the outside of the vacuum chamber are all in the same form and have the same exhaust conductance. There is almost no variation. Therefore, it is possible to form a thin film having a desired film thickness and density while keeping the film formation state by each target substantially the same. Moreover, the flow of the process gas from the vicinity of each target to the exhaust port of the vacuum chamber is collected at the central portion of the vacuum chamber, and thus does not cross each other. Therefore, even when a plurality of types of thin films are formed simultaneously with a plurality of types of targets, contamination due to the mutual mixing of the film components of the plurality of targets can be reliably prevented, and high-quality having desired film characteristics can be obtained. A thin film can be obtained.
[0010]
Further, contaminated air or the like in the lower space provided with a mechanism such as a rotary table rotation holding mechanism can be prevented from flowing into the upper space where the substrate and the target are disposed, and the lower space is contaminated. By exhausting the air and the like separately from the upper space, it is possible to reliably prevent contamination of the film formation by contaminated air and the like.
[0018]
According to a second aspect of the present invention, the ring-shaped partition member is disposed in the vicinity of the lower surface of the rotary table so as to face the annular gap between the peripheral end surface of the rotary table and the inner peripheral wall of the vacuum chamber. It is the structure provided in the surrounding wall.
[0019]
Thereby, the structure which isolate | separates the inside of the vacuum chamber of Claim 1 into an upper space and a support space with a rotary table as a boundary is effectively achieved by the cheap and simple structure which only provides a ring-shaped partition member. Can do.
[0020]
According to a third aspect of the present invention, an exhaust opening having a large exhaust conductance is provided at a central portion of the rotary table, and the rotary table has a rotation holding mechanism at a peripheral portion of the exhaust opening on the lower surface thereof. The exhaust chamber is rotatably supported by a bottom plate portion of the vacuum chamber, and an exhaust port is provided in the bottom plate portion of the vacuum chamber so as to face the exhaust opening portion at an inward position with respect to the mounting portion of the rotation holding mechanism. And an exhaust passage that communicates with each other via a plurality of exhaust communication holes formed along the outer periphery of the attachment portion of the rotation holding mechanism, and the exhaust opening, The exhaust port and the exhaust passage portion constitute an exhaust passage in the upper space of the vacuum chamber, and the exhaust communication hole and the exhaust passage portion constitute a lower space in the vacuum chamber. An exhaust passage is configured.
[0021]
Thereby, the structure which provides the exhaust passage of upper space and the exhaust passage of lower space separately can be achieved cheaply and easily.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a sputtering apparatus according to an embodiment of the present invention. In FIG. 1, the same or equivalent parts as those in FIG. The vacuum chamber 14 is formed in a vacuum container by hermetically combining a chamber frame 17 that forms a chamber peripheral wall and a chamber base 18 that forms the bottom surface of the chamber. A rotary table 19 on which a plurality of substrates 10 are arranged and mounted on the same rotation circle on the upper surface is formed with an exhaust opening 20 at the center of rotation, and the lower surface of the peripheral edge of the exhaust opening 20 is a ball. It is rotatably supported by the chamber base 18 via a rotation holding mechanism 21 made of a bearing or the like. The exhaust opening 20 is formed to have a relatively large diameter so that the exhaust conductance is sufficiently large, that is, the exhaust resistance is sufficiently small.
[0023]
The chamber base 18 has a configuration in which a bottom plate portion 22 and an exhaust passage portion 23 located below the bottom plate portion 22 are integrally formed. The bottom plate portion 22 has an exhaust port 24 having a diameter larger than that of the exhaust opening 20 of the rotary table 19 and is opened at the center portion facing the exhaust opening 20, and is connected to the exhaust passage portion 23 via the exhaust port 24. Communicate. Further, the exhaust passage portion 23 is provided with an exhaust port 27 at the center of the bottom surface so as to face the exhaust port 24 of the bottom plate portion 22, and below the exhaust port 27 on the lower surface of the exhaust passage portion 23, A vacuum exhaust pump 7 is attached via a valve 4. Therefore, when the evacuation pump 7 is driven, the upper space surrounded by the upper surface of the rotary table 19 and the chamber frame 17 inside the vacuum chamber 14 becomes the exhaust opening 20 of the rotary table 19 and the chamber base 18. The exhaust gas is exhausted through the exhaust port 24 of the bottom plate portion 22, the exhaust port 27 of the exhaust passage portion 23, and the valve 4.
[0024]
FIG. 2 is a sectional view taken along line AA in FIG. The rotation holding mechanism 21 that rotatably supports the rotary table 19 is fixed to the peripheral edge of the exhaust port 24 in the bottom plate portion 22 of the chamber base 18, and the bottom plate portion 22 has an attachment portion for the rotation holding mechanism 21. Four arc-shaped exhaust communication holes 28 are formed at equal intervals along the outer periphery of the gas. As shown in FIG. 1, a ring-shaped partition body 29 is fixed to the inner peripheral wall of the chamber frame 17 so as to be close to the lower surface of the rotary table 19. It functions to substantially close the gap between the peripheral end surface and the inner peripheral wall of the chamber frame 17 from below. Thereby, the inside of the vacuum chamber 14 is separated into an upper space and a lower space with the rotary table 19 as a boundary.
[0025]
Therefore, when the evacuation pump 7 is driven, the lower space of the vacuum chamber 14 surrounded by the lower surface of the rotary table 19 in the vacuum chamber 14, the inner peripheral wall of the chamber frame 17, and the bottom plate portion 22 of the chamber base 18 is The exhaust gas is exhausted from the valve 4 through an exhaust passage including four exhaust communication holes 28 in the bottom plate portion 22, an exhaust passage portion 23, and an exhaust port 27 of the exhaust passage portion 23.
[0026]
As shown in FIG. 1, a plurality of electrodes 12 each holding a target 11 via a backing plate 13 are attached to a lid 30 of a vacuum chamber 14 that hermetically covers an upper end opening of a chamber frame 17. . FIG. 3 is a perspective view of the chamber frame 17 as viewed from below. In the figure, the cover 30 is formed with four attachment holes 31 for attaching the electrodes 12 at equal intervals on an arrangement circle 33 indicated by a two-dot chain line in the figure. The four electrodes 12 are respectively inserted into the mounting holes 31 and are fixed to the lid 30 while being kept airtight by the packing 32 of FIG. Therefore, the exhaust opening 20 and the exhaust ports 24 and 27 are concentrically formed on the inner side of the arrangement circle 33 of the four electrodes 12. The target 11 held on each electrode 12 via the backing plate 13 is disposed to face the movement locus of each substrate 10 due to the rotation of the turntable 19. That is, the arrangement circle 33 corresponds to the movement locus of the center point of each substrate 10.
[0027]
As clearly shown in FIG. 3, between the four electrodes 12, a substantially triangular partition wall 34 is integrally projected from the chamber frame 17 in the radial center direction. The partition walls 34 are individually independent. Each electrode 12 is covered with a partition member 37 having an opening with a predetermined diameter. The partition member 37 allows the partition 10 to be separated only when the substrate 10 is positioned directly below the target 11 as the rotary table 19 rotates. The sputtered particles that have passed through the opening of the member 37 reach the substrate 10 to grow a thin film. Thereby, the thin film to be formed has a film characteristic in which the crystal grain growth direction is constant, the direction of magnetic anisotropy is uniform, and the sheet resistance is low. Further, each of the partition members 37 is individually penetrated with four gas introduction pipes 40 attached to the chamber frame 17 so as to individually supply process gas to the vicinity of each electrode 12. Yes.
[0028]
Next, film formation by the sputtering apparatus will be described. The inside of the vacuum chamber 14 is pulled into a high vacuum state by driving the vacuum exhaust pump 7, and a process gas such as argon gas is supplied from each gas introduction pipe 40 to the inside of the vacuum chamber 14 in this high vacuum state. Are introduced individually in the vicinity of each electrode 12. In the process gas atmosphere inside the vacuum chamber 14, by applying a voltage to each of the plurality of targets 11 simultaneously or sequentially from the power supply unit (not shown) via the electrode 12 and the backing plate 13, for example, argon When plasma is generated and ions having high energy are incident on the target 11, sputtered particles are ejected from the target 11, and the sputtered particles are deposited on the substrate 10 through the opening of the partition member 37. Here, the rotary table 19 performs a continuous rotation at a constant speed or a rotary motion that stops for a predetermined time each time the substrate 10 faces the target 11. When the turntable 19 is rotated by a predetermined number of revolutions, film formation by sputtered particles ejected from the four targets 11 is sequentially laminated on each substrate 10 to form a multilayer film.
[0029]
In this sputtering apparatus, the exhaust opening 20 of the rotary table 19, the bottom plate portion 22 of the chamber base 18, and the exhaust ports 24 and 27 of the exhaust passage portion 23 are concentric to the center of the arrangement circle 33 of each electrode 12. The air including the gas in the vicinity of each electrode 12 is formed in the shape of the vacuum exhaust via the exhaust opening 20 and the exhaust ports 24 and 27 each having a sufficiently large exhaust conductance. Is exhausted. Therefore, the exhaust paths from the vicinity of each electrode 12 to the vacuum pump 7 are formed in the same form and the exhaust conductance is set to be the same. There is almost no variation in the pressure state during film formation. Further, the process gas is supplied to the vicinity of each electrode 12 through the gas introduction pipes 40 individually provided for each electrode 12, and from this point, the film is formed at the vicinity of each electrode 12. It is possible to more reliably suppress the occurrence of pressure state variations. Therefore, it is possible to form a thin film having a desired film thickness and density while keeping the film formation state by each electrode 12 substantially the same.
[0030]
On the other hand, the flow of the process gas from the vicinity of each electrode 12 to the vacuum pump 7 is collected in the central portion of the vacuum chamber 14 as indicated by the arrow E1 in FIG. 7 so that they do not cross each other.
[0031]
In addition, a partition wall 34 that is formed integrally with the chamber frame 17 and extends in the radial center direction is interposed between the two adjacent electrodes 12, so that the targets 11 can be connected to each other. It becomes the state where it was isolated and provided independently, and the contamination by the film | membrane component of the other target 11 can be prevented almost certainly.
[0032]
Further, the gap between the peripheral end surface of the turntable 19 and the inner peripheral surface of the chamber frame 17 is set to have a small exhaust conductance, that is, a large exhaust resistance by providing a ring-shaped partition 29. Thereby, the internal space of the vacuum chamber 14 is separated into an upper space and a lower space with the turntable 19 as a boundary. The lower space is exhausted separately from the upper space through the exhaust communication hole 28, the exhaust passage portion 23 and the exhaust port 27 of the bottom plate portion 22 of the chamber base 18 as indicated by an arrow E2 in FIG. Therefore, it is possible to reliably prevent the film formation from being contaminated by the influence of contaminated air or the like by the rotation holding mechanism 21 existing in the lower space.
[0033]
With the above three-point configuration, it is possible to reliably prevent contamination by mutual mixing of film components by a plurality of targets 11, even though a plurality of types of thin films are simultaneously formed by a plurality of types of targets 11. A high-quality thin film having characteristics can be obtained.
[0034]
【The invention's effect】
As described above, according to the sputtering apparatus of the present invention, since the exhaust passage is provided in the central portion of the mounting position of each substrate and the arrangement circle of each target, the vacuum chamber is started from the vicinity of each target. Since the exhaust paths to the outside of the target have the same form and the same exhaust conductance, there is almost no variation in the pressure state during film formation in the vicinity of each target, and film formation by each target is performed. A thin film having a desired film pressure and density can be formed while maintaining the state substantially the same. In addition, since the process gas flows from the vicinity of each target to the discharge port do not intersect each other, even when a plurality of types of thin films are formed simultaneously with a plurality of types of targets, the film components of the plurality of targets are mutually connected. Thus, it is possible to reliably prevent contamination due to contamination and obtain a high-quality thin film having desired film characteristics.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a sputtering apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a perspective view of a chamber frame in the apparatus as seen from below.
FIG. 4 is a longitudinal sectional view showing a conventional sputtering apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Board | substrate 11 Target 12 Electrode 14 Vacuum chamber 17 Chamber frame 18 Chamber base 19 Rotary table 20 Exhaust opening part 21 Rotation holding mechanism part 22 Bottom plate part 23 Exhaust passage part 27 Exhaust port 28 Exhaust communication hole 29 Partition body 33 Arrangement circle 34 Partition 40 Gas introduction pipe

Claims (3)

A vacuum chamber;
A rotary table that is rotatably installed in the vacuum chamber, and a plurality of substrates are respectively arranged at mounting positions on a rotating circle, and
An electrode arranged on an arrangement circle corresponding to the rotation trajectory of the substrate, and individually holding a plurality of targets facing the substrate;
An exhaust passage formed in the central portion of each of the mounting positions of the substrate in the vacuum chamber and the arrangement circle of the electrodes ;
The inside of the vacuum chamber is surrounded by an upper space surrounded by the upper surface of the rotary table and the inner peripheral wall of the vacuum chamber and the substrate and the target are disposed, and the lower surface of the rotary table and the inner peripheral wall of the vacuum chamber. A sputtering apparatus, wherein the spattering apparatus is separated into a lower space, and an exhaust passage in the upper space and an exhaust passage in the lower space are provided separately . A ring-shaped partition member is provided on the inner peripheral wall of the vacuum chamber so as to be opposed to the annular gap between the peripheral end surface of the rotary table and the inner peripheral wall of the vacuum chamber and close to the lower surface of the rotary table. Item 2. The sputtering apparatus according to Item 1 . An exhaust opening having a diameter with a large exhaust conductance is provided at the center of the rotary table,
The rotary table has a peripheral portion of the exhaust opening on the lower surface thereof rotatably supported on the bottom plate portion of the vacuum chamber via a rotation holding mechanism,
An exhaust port is provided in the bottom plate portion of the vacuum chamber so as to face the exhaust opening at an inward position with respect to the mounting portion of the rotation holding mechanism, and the exhaust port and the rotation holding mechanism are attached. Exhaust passage portions communicating with each other via a plurality of exhaust communication holes formed along the outer periphery of the portion are integrally provided,
An exhaust passage in the upper space of the vacuum chamber is configured by the exhaust opening, the exhaust port, and the exhaust passage, and exhaust in the lower space of the vacuum chamber is formed by the exhaust communication hole and the exhaust passage. the sputtering apparatus according to claim 1 or 2 passages are configured.

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