JP2011174148A - Sputtering apparatus - Google Patents

Abstract

A sputtering apparatus capable of forming a thin film with excellent uniformity and reproducibility is provided.
A sputtering apparatus includes a sputtering chamber 1 including a vacuum chamber, a tray transport mechanism that moves while holding a substrate 7 in the sputtering chamber 1, and targets 8 and 9 for forming a thin film on the substrate 7. A sputter cathode that fixes and generates plasma to generate sputtered particles from the targets 8 and 9 and a film thickness correction plate 19 disposed between the substrate 7 and the targets 8 and 9 are provided. The film thickness correction plate 19 has a main body 19a having an anode potential and a frame 19b that holds the main body 19a. The frame portion 19b is substantially in the center of the tray traveling direction of the region where the sputtered particles are generated, and the main body portion 19a is disposed in the vicinity of the substrate 7 passing through the region where the sputtered particles are generated. Hold.
[Selection] Figure 3

Description

  The present invention relates to a sputtering apparatus.

  A sputtering apparatus is known as an apparatus for forming a thin film by generating a plasma of an inert gas between a target installed on a cathode electrode and a substrate installed on an anode electrode, and depositing sputtered particles ejected from the target on the substrate. It has been. However, in the sputtering apparatus, it is difficult to uniformly form the sputtered particles jumping out of the target on the substrate, and various methods have been studied in order to reduce the thickness and variation of the thin film formed on the substrate. .

  For example, in Patent Document 1, a film thickness correction plate having a thickness of 0.3 mm to 1 mm is arranged at a position with a distance of 7 mm to 13 mm from the surface of the substrate to the target side, and the formed thin film is uniform with high accuracy. A sputtering apparatus is described.

JP 2001-49431 A

  However, in a through-film type sputtering apparatus, the tray on which the substrate is mounted functions as an anode when the substrate is formed through the film, and the cathode potential tends to fluctuate due to the movement of the tray. When the fluctuation of the cathode potential is increased, there is a problem that the film thickness distribution in the tray traveling direction of the formed thin film is deteriorated or the reproducibility of the film thickness distribution is deteriorated. For this reason, it is desired to provide a sputtering apparatus capable of forming a thin film having excellent uniformity and reproducibility.

  This invention is made | formed in view of the said problem, and it aims at providing the sputtering device which can form the thin film excellent in the uniformity and reproducibility.

In order to achieve the above object, a sputtering apparatus according to the first aspect of the present invention comprises:
A sputtering chamber consisting of a vacuum chamber;
A moving member that moves while holding the substrate in the sputtering chamber;
A sputter cathode that fixes a target for forming a thin film on the substrate and generates plasma, and generates sputtered particles from the target;
A film thickness correction plate installed between the substrate and the target;
The film thickness correction plate has an anode potential at the main body,
The region where the sputtered particles are generated is disposed in the vicinity of the substrate passing through the region where the sputtered particles are generated, in the approximate center of the moving member traveling direction.

The film thickness correction plate includes, for example, the main body portion and a frame portion that holds the main body portion, and the frame portion is substantially in the center in the moving member traveling direction and substantially in the width direction. The main body is held.
The main body of the film thickness correction plate is grounded, for example.

For example, the main body is formed in an elliptical shape extending in the width direction of the film thickness correction plate.
The movement path of the substrate is, for example, linear. In this case, the moving member reciprocates in the sputtering chamber.

  A plurality of the sputtering cathodes may be provided, and at least one of the sputtering cathodes may be fixed with a target made of a material different from a target fixed to the other sputtering cathode.

  According to the present invention, a thin film having excellent uniformity and reproducibility can be formed.

It is a figure which shows the outline | summary of the sputtering device of this invention. It is a figure which shows the shape of an adhesion prevention board and a film thickness correction board. It is a figure which shows the state by which the adhesion prevention board and the film thickness correction board are arrange | positioned. It is a figure which shows the shape of the conventional adhesion prevention board and a film thickness correction board. It is a figure which shows the relationship between a tray position and a cathode potential. (A) using the film thickness correction plate of this embodiment is a diagram showing the relationship between the tray width position and the film thickness, and (b) is a diagram showing the relationship between the tray width position and the film thickness distribution. (C) is a figure which shows the relationship between a mask and an average film thickness. (A) using a conventional film thickness correction plate is a diagram showing the relationship between the tray width position and the film thickness, (b) is a diagram showing the relationship between the tray width position and the film thickness distribution, c) is a diagram showing the relationship between the mask and the average film thickness. It is a figure which shows the tray used for the measurement of FIG.6 and FIG.7.

  Hereinafter, the sputtering apparatus of this invention is demonstrated with reference to drawings. FIG. 1 is a view showing an outline of the sputtering apparatus of the present invention.

  As shown in FIG. 1, the sputtering apparatus is a load-lock type sputtering apparatus, and includes a sputtering chamber 1 for performing a sputtering film forming process. The sputter chamber 1 is composed of a vacuum chamber, and a preparation / extraction chamber 2 is connected via a gate valve 3. Then, the substrate 7 to be subjected to the sputtering film forming process is mounted on the tray 5 and carried in (or carried out) from the loading / unloading chamber 2 through the gate valve 3.

  The sputter chamber 1 is provided with an exhaust path 1a. The exhaust passage 1a is provided with exhaust means such as a main valve 4 and a vacuum pump (not shown), and the inside of the sputtering chamber 1 is controlled to a predetermined pressure (degree of vacuum) by the exhaust means.

  The sputter chamber 1 includes a tray transport mechanism 6 that transports a tray 5 on which a substrate 7 is mounted, a sputter cathode 81 that holds a pair of targets 8, a sputter cathode 91 that holds a pair of targets 9, a sputter cathode 81, And a power source 11 for applying sputtering power to 91.

  The tray transport mechanism 6 supplies the substrate 7 to a film forming position where a thin film is formed by the sputter cathode 81 and the sputter cathode 91, and the substrate 7 is between the pair of targets 8 and between the pair of targets 9. The loaded tray 5 is passed at a predetermined speed. Thereby, the particles of the material of the sputtered target 8 and the particles of the material of the sputtered target 9 are deposited on the substrate 7, and a thin film is formed on the substrate 7. In the present embodiment, as shown in FIG. 1, the movement path of the substrate 7 is linear, and the tray transport mechanism 6 reciprocates in the sputtering chamber 1.

  For example, the sputtering cathode 81 is provided with a pair of storage areas facing each other, and the target 8 and the magnet 10 that are film forming materials are stored (fixed) in the storage areas. The sputter cathode 91 is provided with a pair of storage areas, for example, and the target 9 and the magnet 10 are stored in the storage areas. In this embodiment, the sputtering apparatus is a sputtering apparatus for forming an electrode on a quartz crystal vibrating piece, and a material of the first electrode layer, for example, chromium (Cr) or nickel (Ni) is disposed as the target 8. As the target 9, a material of the second electrode layer, for example, silver (Ag) or gold (Au) is disposed.

  The power source 11 is connected to the sputter cathodes 81 and 91 via the switch 12. The power supply 11 applies a voltage to the sputtering cathode 81 or the sputtering cathode 91 by switching the switch 12. When a voltage is applied to the sputtering cathode 81 (or sputtering cathode 91) by the power supply 11, plasma is generated at the sputtering cathode 81 (or sputtering cathode 91). Sputtered particles are ejected from the target 8 (or the target 9) by this plasma and deposited on both surfaces of the substrate 7. Thereby, a thin film of the target material is formed on both surfaces of the substrate 7.

  The sputter cathodes 81 and 91 are provided with a deposition preventing plate 18 and a film thickness correcting plate 19. FIG. 2 shows the shapes of the deposition preventing plate 18 and the film thickness correcting plate 19, and FIG. 3 shows a state in which the deposition preventing plate 18 and the film thickness correcting plate 19 are arranged.

  As shown in FIGS. 2 and 3, the deposition preventing plate 18 is disposed in the vicinity of the target 8 so as to cover the ends of the pair of targets 8 of the sputter cathode 81. Further, the deposition preventing plate 18 is disposed in the vicinity of the target 9 so as to cover the ends of the pair of targets 9 of the sputtering cathode 91.

  The film thickness correction plate 19 is made of a conductive material and is maintained at the anode potential. In this example, the film thickness correction plate 19 is set to the ground potential, but a voltage may be applied or an anode power source may be separately provided. In the sputtering apparatus shown in FIG. 1, the sputtering chamber 1, the earth shield (not shown), the deposition preventing plate 18, and the film thickness correcting plate 19 are grounded to have an anode potential. As shown in FIG. 2, the film thickness correction plate 19 is composed of a main body portion 19a and a frame portion 19b. The main body portion 19a is formed at the center of the film thickness correction plate 19 in the width direction (direction perpendicular to the tray 5 traveling direction). In the drawing, the tray traveling direction is indicated by an arrow x, and the tray width direction (width direction) perpendicular to the tray traveling direction is indicated by an arrow z. In the present embodiment, the main body 19 a is formed in an elliptical shape that extends in the width direction of the film thickness correction plate 19. The frame part 19b is formed so as to hold the main body part 19a. In the frame portion 19b, the main body portion 19a is substantially the center of the sputter cathode 81 (a region where sputtered particles are generated) in the tray 5 traveling direction, and the main body portion 19a is disposed in the vicinity of the substrate 7 passing through the front surface of the sputter cathode 81. It is formed to be. Such a film thickness correction plate 19 is formed on each of the pair of targets 8 of the sputter cathode 81. Therefore, in a state where the film thickness correction plate 19 is disposed on each of the pair of targets 8 of the sputter cathode 81, the main body portion 19 a is in the vicinity of the substrate 7 that passes through the sputter cathode 81 and the sputter cathode 81 (target 8 ). A similar film thickness correction plate 19 is also disposed on the sputter cathode 91. It is desirable that the frame portion 19b be formed larger than the outer shape of the targets 8 and 9 to reduce the shadow caused by the frame portion and improve the film formation rate. In this example, the tray traveling direction width of the frame portion 19b is formed larger than the tray traveling direction width of the targets 8 and 9, thereby preventing the sputtered particles reaching the substrate from being blocked by the frame portion.

  The sputtering chamber 1 is provided with a gas introduction path 20 a for introducing a sputtering gas, for example, argon (Ar) into the sputtering chamber 1. A gas supply valve 20b is provided in the gas introduction path 20a. By opening the gas supply valve 20b, the sputtering gas is introduced into the sputtering chamber 1 through the gas introduction path 20a.

  The control device 17 is constituted by a microprocessor, a sequencer, or the like, and controls the operation of each part of the sputtering apparatus.

  An exhaust passage 2 a is provided in the preparation / extraction chamber 2 connected to the sputtering chamber 1 via the gate valve 3. The exhaust passage 2a is provided with exhaust means such as a main valve 4 and a vacuum pump (not shown), and the inside of the charging / extracting chamber 2 is controlled to a predetermined pressure (degree of vacuum) by the exhaust means. Specifically, when the tray 5 (substrate 7) is carried in and out, the atmosphere is released or evacuated. For example, after the inside of the preparation / extraction chamber 2 is evacuated by the exhaust means, the gate valve 3 is opened, and the tray 5 (substrate 7) is transferred from the preparation / extraction chamber 2 to the sputtering chamber 1. In addition, a heater 21 is disposed in the preparation / extraction chamber 2. The heater 21 heats the substrate 7 to a desired temperature.

  Next, the operation of the sputtering apparatus configured as described above (a method for forming a thin film using the sputtering apparatus) will be described. The operation of each part of the sputtering apparatus is controlled by the controller 17.

  First, the main valve 4 is opened and a vacuum pump (not shown) is operated to evacuate the sputtering chamber 1 until a predetermined degree of vacuum is reached. Next, the gas supply valve 20b is opened, and Ar gas is introduced into the sputtering chamber 1 from the gas introduction path 20a. Then, the gas supply valve 20b is adjusted to control the inside of the sputtering chamber 1 to a predetermined gas pressure.

  Next, the switch 12 is controlled to connect the power supply 11 and the sputtering cathode 81. Then, the power supply 11 is turned “on”, and a voltage is applied to the sputtering cathode 81 to generate plasma. Thereafter, the gate valve 3 is opened, and the tray 5 on which the substrate 7 is mounted is transported from the preparation / extraction chamber 2 into the sputtering chamber 1. In addition, after heating the substrate 7 with the heater 21 as necessary, the tray 5 (substrate 7) may be transported from the preparation / extraction chamber 2 into the sputtering chamber 1.

  Subsequently, the tray transport mechanism 6 is controlled so that the tray 5 on which the substrate 7 is mounted is transported at a constant speed at a film forming position where a thin film is formed by the sputtering cathode 81. At the film forming position, Ar ions generated in the plasma collide with the target 8, sputtered particles are ejected from the target 8 (for example, Cr), and the sputtered particles are deposited on the substrate 7. Thereby, a thin film (Cr film) is formed on both surfaces of the substrate 7.

In general, a large amount of sputtered particles jumping out of the target 8 are deposited in the central portion in the width direction of the substrate facing each other. Therefore, by arranging a film thickness correcting plate 52 as shown in FIG. It is shielded and the film thickness in the tray width direction is made uniform.
However, in the conventional sputtering apparatus, since the tray 5 on which the substrate 7 is mounted also functions as an anode, the movement of the tray 5 makes the plasma (cathode potential) unstable, and the film thickness distribution in the tray traveling direction is It was easy to get worse.
In the sputtering apparatus of the present invention, the film thickness correction plate 19 for adjusting the film thickness in the tray width direction is disposed in the center of the front surface of the sputtering cathode 81 (target 8). The film thickness correction plate 19 (main body portion 19a) functions as a main anode, and the fluctuation of plasma (cathode potential) caused by the movement of the tray 5 is reduced. Make reproducibility good.
A correction plate that adjusts the film thickness in the tray width direction may be provided separately from the anode placed facing the center of the front of the cathode for the purpose of reducing plasma fluctuations. By adjusting the film thickness in the tray width direction according to its shape while suppressing fluctuations in film thickness in the direction, the area of the shield on the front surface of the target can be reduced. is there.

  Next, the switch 12 is controlled to connect the power supply 11 and the sputtering cathode 91. Then, the power supply 11 is turned “on”, and a voltage is applied to the sputtering cathode 91 to generate plasma. Thereafter, the tray transport mechanism 6 is controlled so that the tray 5 on which the substrate 7 is mounted is transported at a constant speed at the film forming position where the thin film is formed by the sputter cathode 91. At the film forming position of the sputter cathode 91, Ar ions generated by the plasma collide with the target 9, and sputter particles are ejected from the target 9 (for example, Ag), and the sputter particles are deposited on the substrate 7. Thereby, a thin film (Ag film) is formed on both surfaces of the substrate 7. As a result, a two-layer thin film of a Cr film and an Ag film is formed on both surfaces of the substrate 7.

  As described above, at the film forming position of the sputter cathode 91, the main body 19 a of the film thickness correction plate 19 is in the vicinity of the substrate 7 passing through the sputter cathode 91 and in the central portion of the sputter cathode 91 (target 9). Has been placed. For this reason, in the sputtering apparatus of the present invention, the film thickness distribution of the formed thin film in the traveling direction of the tray 5 and the reproducibility are improved. As a result, a thin film having excellent uniformity and reproducibility can be formed.

  Subsequently, the power supply 11 is turned off, the gas supply valve 20b is closed, and the introduction of Ar gas from the gas introduction path 20a into the sputtering chamber 1 is completed. Further, a vacuum pump (not shown) is operated to evacuate the Ar gas in the sputtering chamber 1 and evacuate until a predetermined degree of vacuum is reached. Next, the tray transfer mechanism 6 is controlled to transfer the tray 5 on which the substrate 7 is mounted in the direction of the gate valve 3, then the gate valve 3 is opened, and the tray on which the substrate 7 is mounted from inside the sputtering chamber 1. 5 is transferred into the charging / unloading chamber 2. Thereby, formation of the thin film using a sputtering apparatus is complete | finished.

  Next, in order to confirm the effect of the present invention, the fluctuation of the cathode potential during film formation when the film thickness correction plate 19 was used was confirmed. For comparison, the same measurement was performed when a conventional film thickness correction plate was used. FIG. 4 shows the shapes of a conventional deposition preventing plate 51 and film thickness correcting plate 52. FIG. 5 shows the measurement results.

  As shown in FIG. 5, it was confirmed that the fluctuation of the cathode potential was reduced by using the film thickness correction plate 19 rather than using the conventional film thickness correction plate. When a conventional film thickness correction plate is used, the plasma fluctuates due to the tray entering or leaving the cathode front surface (in FIG. 5, the cathode potential rises when the tray enters and when the tray exits). However, it can be seen that by using the film thickness correction plate of the present invention, plasma fluctuation due to passage through the tray was suppressed.

Moreover, the result of having measured the film thickness distribution on a tray about the case where the film thickness correction | amendment board 19 was used for the film-passing on a board | substrate is shown in FIG. Using three masks 61 to 63 shown in FIG. 8, the film thickness at each position of 7 rows and 3 columns on the tray 5 was measured. Three measurement points are formed on the three masks at intervals of 15 mm in the tray width direction, and each mask is arranged in three rows at intervals of 130 mm in the tray traveling direction. Masks 61 and 63 are disposed at the ends in the tray traveling direction, and a mask 62 is disposed at the center. FIG. 6A plots the film thicknesses of seven measurement points formed in the range of ± 45 mm in the tray width direction with a target center height of 0 mm as the tray width position for each mask. FIG. 6B shows the film thickness distribution between the masks at the seven measurement points, that is, the film thickness distribution in the tray traveling direction. FIG. 6C shows the average film thickness in the mask. For comparison, the same measurement was performed for the case where a conventional film thickness correction plate was used to form a film on a substrate. The result is shown in FIG.
For example, when the amount of sputtered particles released from the target and the transport process are stationary, the tray is deposited while passing through the front surface of the target at a constant speed, so the film thickness on the straight line in the tray traveling direction is always constant. It should be. However, it can be seen that the thickness of each mask is different at each position of the tray width. This variation is remarkable when the conventional film thickness correction plate shown in FIG. 7 is used, and is caused by the fact that the plasma fluctuates as the tray moves on the front surface of the target as described above.

  On the other hand, in FIG. 6, it can be confirmed that the film thickness distribution in the traveling direction of the tray 5 is improved by using the film thickness correction plate 19. This is because the film thickness correction plate 19 faces the center of the front surface of the sputter cathodes 81 and 91 and functions as the main anode, so that the function as the anode of the tray 5 is weakened and plasma fluctuations due to movement of the tray 5 are suppressed. This is because. Moreover, when the measurement was performed a plurality of times, it was confirmed that the reproducibility was good. For this reason, it was confirmed that the film thickness distribution of the formed thin film in the traveling direction of the tray 5 and the reproducibility were improved by using the film thickness correction plate 19.

  As described above, according to the embodiment of the present invention, the main body portion 19 a of the film thickness correction plate 19 is in the vicinity of the substrate 7 passing through the sputter cathodes 81, 91, and the sputter cathodes 81, 91. Since it is arranged at the center, the film thickness distribution of the formed thin film in the traveling direction of the tray 5 and the reproducibility are improved. As a result, a thin film having excellent uniformity and reproducibility can be formed.

  In addition, this invention is not restricted to said embodiment, A various deformation | transformation and application are possible. Hereinafter, other embodiments applicable to the present invention will be described.

In the above-described embodiment, the present invention has been described by taking as an example the case where the shape of the main body portion 19a of the film thickness correction plate 19 is formed in an elliptical shape extending in the width direction. What is necessary is just to be arranged in the vicinity of the substrate 7 passing through 91 and in the central part of the sputter cathodes 81, 91. For example, it may be circular or square. When the main body 19a is to function as a film thickness distribution adjusting plate in the tray width direction, the film thickness distribution in the tray width direction is measured or calculated in advance so as to obtain a desired film thickness distribution (in the case of uniformization, the film thickness). The width in the tray traveling direction of the film thickness correction plate may be adjusted so that the thickened portion is cut off.
Furthermore, a heating mechanism and a cooling mechanism may be provided on the film thickness correction plate 19 as necessary. Normally, stainless steel is used as the material for the film thickness correction plate and the support part, but it can be made of a material with high thermal conductivity such as anodized aluminum or copper, and the cross-sectional area of the support member is increased. The temperature increase of the film thickness correction plate main body 19a may be suppressed by increasing heat conduction and by directly mounting a cooling mechanism such as a water cooling mechanism on the film thickness correction plate main body 19a and the support. .

  In the above embodiment, the present invention has been described by taking the case of a sputtering apparatus in which two sputtering cathodes 81 and 91 are provided and two electrode films are formed on both surfaces of the substrate 7. May be a sputtering device having one sputtering device or three or more sputtering cathodes. Moreover, the sputtering apparatus which forms a thin film on the single side | surface of the board | substrate 7 may be sufficient. Further, the present invention is not limited to the formation of the electrode film on the crystal vibrating piece, and can be applied to various targets and substrates.

  In the above embodiment, the switch 12 is used to switch the application of power to each sputtering cathode, but each sputtering cathode may be individually controlled using a separate power source. Further, in the above embodiment, the loading / unloading of the substrate 7 with respect to the sputtering chamber 1 is configured as the single loading / unloading chamber 2, but the loading / unloading may be performed independently in separate chambers. Further, the film forming conditions such as the material to be formed on the substrate 7 and the kind of the sputtering gas can be arbitrarily selected.

  The present invention is useful for a sputtering apparatus.

DESCRIPTION OF SYMBOLS 1 Sputter | spatter chamber 2 Preparation taking-out chamber 3 Gate valve 4 Main valve 5 Tray 6 Tray conveyance mechanism 7 Substrate 8, 9 Target 10 Magnet 11 Power supply 12 Switcher 17 Controller 18 Deposition plate 19 Film thickness correction plate 19a Main body 19b Frame 20a Gas introduction path 20b Gas supply valve 21 Heater 81, 91 Sputter cathode

Claims (6)

A sputtering chamber consisting of a vacuum chamber;
A moving member that moves while holding the substrate in the sputtering chamber;
A sputter cathode that fixes a target for forming a thin film on the substrate and generates plasma, and generates sputtered particles from the target;
A film thickness correction plate installed between the substrate and the target;
The film thickness correction plate has an anode potential at the main body,
A sputtering apparatus, wherein the sputtering apparatus is arranged in the vicinity of a substrate passing through the region where the sputtered particles are generated and is substantially in the center of the moving member traveling direction of the region where the sputtered particles are generated. The film thickness correction plate is composed of the main body portion and a frame portion that holds the main body portion,
2. The sputtering apparatus according to claim 1, wherein the frame portion holds the main body portion at a substantially center in the moving member traveling direction and a substantially center in the width direction.   The sputtering apparatus according to claim 1, wherein a main body portion of the film thickness correction plate is grounded. The main body is formed in an elliptical shape extending in the width direction of the film thickness correction plate.
The sputtering apparatus according to any one of claims 1 to 3.   5. The sputtering apparatus according to claim 1, wherein a movement path of the substrate is linear, and the moving member reciprocates in the sputtering chamber. 6.   6. The sputtering cathode according to claim 1, wherein a plurality of the sputtering cathodes are provided, and at least one of the sputtering cathodes has a target made of a material different from a target fixed to the other sputtering cathode fixed thereon. The sputtering apparatus according to any one of the above.

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