JPWO2013099061A1 - Sputtering equipment - Google Patents

Abstract

The present invention provides a sputtering apparatus capable of improving a target utilization rate in magnetron sputtering for a band-shaped substrate. A sputtering apparatus according to an embodiment of the present invention is a sputtering apparatus that continuously conveys a grounded metal strip substrate in a chamber and performs sputtering on the strip substrate. The sputtering apparatus is provided so as to face a belt-like substrate in a chamber, a target holder for holding the target, a voltage applying means for generating plasma in the chamber by supplying power to the target holder, and a target A magnet unit having a long first magnet disposed on the back side of the holder and a second magnet disposed so as to surround the first magnet, and a direction of the chamber from the magnet unit toward the belt-shaped substrate And a first shield having a floating potential that is provided between the wall surface and the belt-like substrate and shields the wall surface from plasma.

Description

  The present invention relates to a sputtering apparatus, and more particularly to a sputtering apparatus that performs sputtering film formation on a strip-shaped substrate.

  Conventionally, when manufacturing a thin film solar cell, a glass substrate is conveyed one by one, and a desired thin film is formed on the glass substrate by a magnetron sputtering method. However, in recent years, a so-called roll-to-roll system using a strip substrate has been adopted for the purpose of improving productivity and reducing manufacturing costs. Patent Document 1 discloses an apparatus for forming a film on a belt-like substrate by passing the belt-like substrate continuously through a film forming chamber in the longitudinal direction thereof.

JP 2010-150635 A JP-A-6-136511 Japanese Patent Laid-Open No. 9-7949 JP 2000-144407 A JP 2007-32226 A JP 11-350130 A

  In recent years, in a manufacturing process of a CIGS thin film solar cell or the like, a metal is used as a belt-like substrate so as to withstand an annealing process of 500 ° C. or higher. Furthermore, in order to simplify the apparatus configuration, the strip substrate is often grounded in terms of potential. For example, if the substrate is to be floated, it is necessary to take insulation measures for all substrate transport systems. In addition, since the metal substrate is easy to conduct electricity, it is necessary to sufficiently consider the clearance between the apparatus components near the substrate and the substrate. Thus, floating the substrate requires more labor and cost than setting the substrate to the ground potential, and therefore the strip-shaped substrate is often set to the ground potential in order to simplify the device configuration.

  In addition, in the magnetron sputtering method, the plasma ring formed by the rectangular magnets disposed on the back surface of the target has a high plasma density at both ends in the longitudinal direction of the target, and as a result, at both ends in the longitudinal direction of the target. The erosion is deeply formed as compared with the central portion of the target. Thus, the deepest part of erosion is formed at both ends of the target, so that the target utilization rate is lowered as a whole. In the past, various attempts have been made to improve target utilization, but fortunately, in many cases low resistance (mainly metal) targets have been used, resulting in less significant target utilization. There was no decrease in rate. Therefore, these problems were rarely taken up so much.

However, when using a high resistance target such as a CIGS-based thin film solar cell, a phenomenon in which the target utilization rate is significantly reduced as compared with a low resistance one was confirmed. There has been a further need for improvement.
An object of the present invention is to provide a sputtering apparatus capable of improving a target utilization rate in magnetron sputtering for a band-shaped substrate.

In order to solve the problem of reduction of the target utilization rate in the belt-shaped substrate, the present inventors have made various attempts mainly to improve the rectangular magnet disposed on the back surface of the target, but have not obtained satisfactory and satisfactory results. .
As a result of intensive studies, the present inventors have discovered a method for improving the target utilization rate.

  In order to achieve the above object, one embodiment of the present invention is a sputtering apparatus that continuously transports a grounded metal band-shaped substrate in a chamber and performs sputtering on the band-shaped substrate. A target holder for holding the target, a voltage applying means for generating plasma in the chamber by applying a voltage to the target holder, and a target holder A magnet unit that is disposed on the opposite side of the surface on which the target is held, has a long first magnet, and a second magnet that is disposed so as to surround the first magnet, and the chamber Is provided between the belt-shaped substrate and a wall surface that exists in a direction from the magnet unit toward the belt-shaped substrate, and the wall surface is removed from the plasma. Comprising a first shield for 蔽, the said first shield, characterized in that a floating potential.

  ADVANTAGE OF THE INVENTION According to this invention, the sputtering apparatus which can improve a target utilization factor in the magnetron sputtering with respect to a strip | belt-shaped board | substrate can be provided.

It is a schematic sectional side view of the continuous film-forming apparatus which concerns on 1st Embodiment of this invention. 1 is a perspective top view of a continuous film forming apparatus according to a first embodiment of the present invention. It is detailed explanatory drawing of the rectangular magnet unit 10 of 1st Embodiment of this invention. It is front sectional drawing of the film-forming chamber 3 of 1st Embodiment of this invention. 6 is a front sectional view of a film formation chamber 3 of Comparative Example 1. FIG. It is a schematic sectional side view of the continuous film-forming apparatus which concerns on 2nd Embodiment of this invention. It is a transparent top view of the continuous film-forming apparatus which concerns on 2nd Embodiment of this invention. It is a top view explaining the detail of the magnet unit 10 in the rotary cathode 40 which concerns on 2nd Embodiment of this invention. It is sectional drawing explaining the detail of the magnet unit 10 in the rotary cathode 40 which concerns on 2nd Embodiment of this invention. It is a front view of the apparatus of the comparative example 2. It is a block diagram of the apparatus of the comparative example 3. It is sectional drawing of the apparatus of the comparative example 4. It is sectional drawing of the apparatus of the comparative example 5. It is sectional drawing of the apparatus of the comparative example 6. It is a perspective view which shows schematic arrangement | positioning of the apparatus of the comparative example 6. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to this embodiment, In the range which does not deviate from the summary, it can change suitably. In the drawings described below, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

(First embodiment)
Below, typical embodiment of this invention is described based on an accompanying drawing.
FIG. 1 is a schematic sectional side view of a continuous film forming apparatus according to the first embodiment of the present invention.
The continuous film forming apparatus is an apparatus called a so-called roll-to-roll system. The continuous film forming apparatus includes a substrate supply chamber 2 having an unwinding roll 30 in which the band-shaped substrate 1 is wound in a roll shape, and a film forming chamber 3 for forming a thin film on the band-shaped substrate 1 unwound from the unwinding roll 30. A winding roll 31 for winding the belt-like substrate 1 on which a thin film is formed, and a substrate winding chamber 4 having a grounded winding roll 31. In the present embodiment, since the winding roll 31 is grounded, the belt-like substrate 1 supplied from the winding roll 30 and wound around the winding roll 31 is in a grounded state. The unwinding roll 30 may be grounded. That is, at least one of the unwinding roll 30 and the winding roll 31 may be grounded.

  As the unwinding roll 30 and the winding roll 31 rotate, the belt-like substrate 1 is continuously conveyed from the right side to the left side in FIG. An inlet for introducing the belt-like substrate 1 supplied from the unwinding roll 30 into the film forming chamber 3 is provided on the side surface of the film forming chamber 3 on the unwinding roll 30 side. On the side surface of the take-up roll 31, a lead-out port for taking out the belt-like substrate 1 passing through the film forming chamber 3 to the take-up roll 31 is provided.

  On the ceiling wall of the film forming chamber 3, the target 19 held by the target holder 12 and the target 19 held by another target holder are opposed to the surface of the belt-like substrate 1, and the longitudinal direction of the belt-like substrate 1. Are arranged side by side. Each target holder 12 is provided with a voltage application unit 11 that applies a voltage to the target holder 12. The voltage application unit 11 generates a plasma 22 between the target 19 and the belt-like substrate 1 having a grounded conductive surface by applying a DC voltage to the target 19. You may do. The film formation chamber 3 is also provided with a gas introduction part (not shown) for introducing a process gas such as an inert gas such as argon or a reactive gas such as oxygen, and an exhaust part (not shown) for exhausting the film formation chamber 3. (Not shown). The target holder 12 is also called a backing plate and is a metal plate.

  Further, outside the film forming chamber 3, rectangular magnet units 10 are arranged on the back side of each target 19 (on the side opposite to the target holding surface of the target holder 12, that is, on the side opposite to the discharge space (plasma generation region)). Has been. These rectangular magnet units 10 can be reciprocated along the longitudinal direction of the belt-like substrate 1 by a swinging portion (not shown).

  As the material of the belt-like substrate 1, a conductive member having heat resistance capable of annealing at about 500 ° C. is preferable, and a relatively inexpensive metal such as aluminum is used. In this example, the belt-like substrate 1 is grounded by using the metal belt-like substrate 1 and grounding the take-up roll 31. By doing so, the process gas supplied into the film forming chamber 3 can be turned into plasma by the potential difference generated between the target 19 to which a voltage is applied and the grounded belt-like substrate 1.

  In this example, one sputtering apparatus is used as the film formation chamber 3, but a plurality of film formation chambers may be provided.

  The chamber constituting the film forming chamber 3 is connected to the ground. The target shield 14 is connected to the ground. On the other hand, the shield 15 for shielding the inner wall of the film forming chamber 3 from the plasma generated in the film forming chamber 3 has a floating potential. The floating potential shield 15 extends from the target holder 12 toward the strip substrate 1 (the bottom surface of the film forming chamber 3) from the bottom surface shield (first shield) 15a that shields the bottom wall of the chamber 3 from the plasma 22. A side shield (second shield) 15b configured to surround at least a region between the target holder 12 and the belt-like substrate 1 and shields the side wall of the chamber 3 from the plasma 22, and a ceiling wall of the chamber 3 (excluding the target 19). ) Is shielded from the plasma 22. The bottom shield 15 a is supported by the insulator 16. The side shield 15b is connected to the bottom shield 15a, and the ceiling shield 15c is connected to the side shield 15b. The bottom shield 15 a is a shield provided between the bottom surface 3 a of the film forming chamber 3 (the wall surface of the film forming chamber 3 existing in the direction from the rectangular magnet unit 10 toward the strip substrate 1) and the strip substrate 1. The side shield 15 b is a shield that extends from the rectangular magnet unit 10 toward the band-shaped substrate 1 (the bottom surface of the film formation chamber 3) and surrounds at least a region between the target holder 12 and the band-shaped substrate 1. The ceiling shield 15 c is a shield that covers the periphery of the target 19, and has an opening 15 d for exposing the target 19 to a discharge space that is a space in which the plasma 22 is generated. The ceiling shield 15c is a plate-like shield arranged so as to cover the ceiling, and is formed by adding plate-like shields so that the opening 15d is formed. The ceiling shield 15c only needs to be able to expose the target 19 to the plasma 22 while shielding the ceiling from the plasma 22, and may be an annular shield such as a ring-shaped shield.

  Generally, stainless steel is used as the material of the shields 15a, 15b, and 15c. That is, in this embodiment, at least a discharge space in which the plasma 22 is generated is included by the bottom shield 15a, the side shield 15b, and the ceiling shield 15c having the opening 15d for exposing the target 19 to the plasma 22, which are floating potentials. Surrounding the region, the target 19 is exposed to the plasma 22 in the opening 15d. Therefore, it can be said that the plasma 22 is substantially generated in a region defined by the target 19 (target holder 12), the bottom shield 15a, the side shield 15b, and the ceiling shield 15c. Since the band-shaped substrate 1 having a grounded conductive surface passes through the region, the region of the side shield 15b on the side of the unwinding roll 30 and the side of the winding roll 31 is respectively a band-shaped substrate. An opening for passing 1 is provided.

  The belt-like substrate 1 is a thin metal having a thickness of 2 mm or less, more preferably 1 mm or less, and is wound while applying a predetermined tension by a support member such as an unwinding roll 30, a winding roll 31, or a roller (not shown). It is conveyed while being. If the belt-like substrate 1 is exposed to the plasma space, it may expand due to heat. Therefore, if the belt-like substrate 1 is excessively tensioned by the support member, there is a risk of wrinkling or thermal deformation. Therefore, the belt-like substrate 1 can be tensioned only to some extent, and the belt-like substrate 1 is usually bent downward by its own weight. Therefore, the distance between the support member that supports the belt-like substrate 1 and the bottom shield 15a is designed to be 20 mm or more so that the grounded belt-like substrate 1 and the bottom shield 15a having the floating potential do not come into contact with each other. In order to secure a plasma generation region, the distance between the target holder 12 and the strip substrate 1 is preferably 30 mm or more, more preferably 50 mm or more. In this example, the distance D1 between the target holder 12 and the belt-like substrate 1 is 70 mm, and the distance D2 between the target holder 12 and the bottom shield 15a is 120 mm.

FIG. 2 is a transparent top view of the continuous film forming apparatus according to the first embodiment of the present invention.
As shown in FIG. 2, a rectangular magnet unit 10 is disposed above the rectangular target 19. The erosion in the longitudinal direction of the rectangular target 19 is designed to be longer than the river width of the strip substrate 1. That is, the rectangular magnet unit 10 is longer than the river width of the belt-like substrate 1. The rectangular magnet unit 10 can be reciprocated along the longitudinal direction of the belt-like substrate 1 by a swinging portion (not shown).

FIG. 3 is a detailed explanatory view of the rectangular magnet unit 10 according to the first embodiment of the present invention.
As shown in FIG. 3, the rectangular magnet unit 10 includes a central magnet 20 b, a peripheral magnet 20 a disposed around the central magnet 20 b, and a yoke plate 21. The surfaces on the target side of the central magnet 20b and the surrounding magnet 20a have different polarities. In addition, the magnet unit 10 is not limited to a rectangular shape as shown in FIG. 3, and a magnet unit having a long first magnet and a second magnet arranged so as to surround the first magnet. If so, the surrounding magnet 20a may be elliptical.

FIG. 4 is a front sectional view of the film forming chamber 3 according to the first embodiment of the present invention.
In FIG. 4, the belt-like substrate 1 is transported from the back side to the near side on the paper surface, and the rectangular magnet unit 10 reciprocates along the near side direction from the back side on the paper surface. As shown in FIG. 4, the width of the target 19 in the longitudinal direction is longer than the river width of the strip-shaped substrate 1 so that a thin film having a uniform film thickness can be formed on the entire substrate. The shield 15 for shielding the inner wall of the chamber 3 has a floating potential by interposing an insulator 16 between the shield 15 and the grounded chamber 3. In the present embodiment, the insulator 16 that is a support portion of the shield 15 and maintains the floating state of the shield 15 is hidden from the plasma 22 by the bottom shield 15a. That is, since the insulator 16 supports the bottom shield 15a so as not to face the plasma 22, when the target 19 is a conductive member, sputter particles do not adhere to the insulator 16. That is, it is possible to prevent or reduce the adhesion of sputtered particles to the insulator 16 for ensuring the floating state of the shield 15, and to keep the floating potential of the shield 15 good even if sputtering is performed for a long time. Can do.

  In the present embodiment, the shield 15 is configured to shield not only the bottom wall (bottom surface 3 a) of the chamber 3 but also the side walls on both sides and the ceiling wall excluding the target 19. In such a configuration, the leakage magnetic flux formed on the plasma surface of the target 19 by the rectangular magnet unit 10 generates a portion having a high plasma density, that is, a plasma ring. The electrons in the plasma do not flow into the shield 15 having the floating potential, but flow into only the grounded belt-like substrate 1, so that the plasma 22 can be concentrated between the target 19 and the belt-like substrate 1. As a result, erosion formed at both ends in the longitudinal direction of the target is reduced, and the utilization factor of the target can be improved.

  In the present embodiment, it is important to prevent the plasma density from becoming as high as possible at both ends in the major axis direction of the rectangular magnet unit 10 (left and right ends in FIG. 4). In order to achieve this, by providing the shield 15 with a floating potential so as to surround the plasma 22, it is possible to reduce the diffusion of electrons to both ends in the longitudinal direction of the plasma 22. That is, since the diffusion of electrons can be reduced by the shield 15 having the floating potential, the high plasma density distribution at both ends in the major axis direction of the rectangular magnet unit 10 can be relaxed. Considering this, it can be said that the effect of the present embodiment can be obtained by setting at least the bottom shield 15a to the floating potential. This is because, when the bottom shield 15a is at a floating potential, the action of driving the electrons to be diffused to the region between the target 19 and the belt-like substrate 1 having a grounded conductive surface is exerted. .

(Comparative Example 1)
FIG. 5 is a front cross-sectional view of the film forming chamber 3 of the first comparative example.
Unlike the film forming chamber shown in FIG. 4, the shield 18 for shielding the inner wall of the chamber 3 is connected to the grounded chamber 3 through a conductive material 17 so as to have a ground potential. . In such a case as well, most of the electrons in the plasma formed between the target 19 and the strip substrate 1 flow into the grounded strip substrate 1. However, when the grounded shield 18 is used as in the comparative example 1, only a part of the electrons in the plasma formed between the target 19 and the strip substrate 1 flows into the grounded shield 18. The plasma diffuses slightly. This is considered to cause uneven distribution of plasma at both ends in the longitudinal direction of the plasma ring, and as a result, cause a reduction in target utilization.

(Comparative Example 2)
FIG. 9 is a front view of the apparatus of Comparative Example 2 (Patent Document 2). The apparatus of Comparative Example 2 is an apparatus for performing a bombardment process, which is a preprocess for removing moisture, hydrocarbons, oxide films, and the like adsorbed on the surface of the metal strip 102 before sputtering. That is, the apparatus of Comparative Example 2 causes the metal strip 102 to run continuously in the vacuum chamber 101 and causes glow discharge between the anode electrode 107 and the metal strip 102 in the vacuum chamber 101 to generate metal. The strip plate 102 is continuously subjected to coating pretreatment (bombardment treatment).

  In Patent Document 2, in a processing chamber that performs bombardment processing, there are many parts that are held at a ground potential, including the chamber itself, and these are also at a negative potential relative to the anode electrode. The problem is that discharge occurs. In the apparatus shown in FIG. 9, the anode electrode 107 and the metal strip 102 in the processing region are covered with a double metal shield composed of an inner shield 105 and an outer shield 106 provided close to each other. The glow discharge is generated by setting the shield 105 to the anode potential or the floating potential and the outer shield 106 to the ground potential. Therefore, the inner shield 105 is held at the anode potential, the discharge space is surrounded by the inner shield 105 having the anode potential, and the metal strip 102 is the only cathode present in the discharge space. Accordingly, a stable glow discharge can be formed between the anode electrode 107 and the inner shield 105 and the metal strip 102. In addition, when coating is performed by, for example, vacuum deposition, it is desirable in terms of equipment that the metal strip 2 is at ground potential.

  Thus, the apparatus of Comparative Example 2 disclosed in Patent Document 2 is related to the present embodiment shown in FIG. 4 in that the metal strip 2 is at the ground potential and the inner shield 105 is at the floating potential. Common with the film forming chamber 3. However, unlike the film formation chamber 3 shown in FIG. 4, the apparatus of Comparative Example 2 does not include the rectangular magnet unit 10 or the target 19, and therefore does not intend the problem of the present invention to improve the use efficiency of the target. . In addition, the inner shield 105 having a floating potential in the apparatus of Comparative Example 2 functions so as to limit the member that becomes a cathode to the discharge plasma to the metal strip 102 as described above.

(Comparative Example 3)
FIG. 10 is a configuration diagram of the apparatus of Comparative Example 3 (Patent Document 3). The apparatus of Comparative Example 3 includes an RF electrode 230 having a collimator 221 disposed inside the sputtering film forming chamber 224, an RF power source 222 connected to the RF electrode 230, and a sputtering provided on the inner wall of the sputtering film forming chamber 224. A shield plate 215 that is insulated from the film forming chamber 224 is provided. Furthermore, the apparatus of Comparative Example 3 is configured so that the silicon substrate 210 can be grounded via the switch 214. The apparatus of Comparative Example 3 is configured such that the target 226 is grounded and the shield plate 215 is in a floating state. In Patent Document 3, it is an object to eliminate the adhesion of the sputtered substance to the collimator and the inner wall of the chamber, thereby making it unnecessary to stop the apparatus for inspection. In the apparatus illustrated in FIG. 10, by providing the shield plate 215, it is possible to prevent the sputtered material from adhering to the inner wall of the sputtering film formation chamber 224. Further, since the shield plate 215 is in a floating state, a negative bias equivalent to the self-bias generated in the collimator 221 is generated. Therefore, the sputtered material attached to the shield 215 can be easily sputtered, and the shield plate 215 can be cleaned.

  As described above, the apparatus of Comparative Example 3 is provided with the target 226, the shield plate 215 is in a floating state, and the substrate is grounded. 3 and common. However, unlike the film formation chamber 3 shown in FIG. 4, the apparatus of Comparative Example 3 is intended to sputter on the circular silicon substrate 210, so that the target 226 has a circular shape instead of a rectangular shape. Moreover, when providing a magnet unit in the apparatus of the comparative example 3 shown in FIG. 10, this magnet unit also becomes circular shape. Therefore, in Patent Document 3, the plasma density is increased at both ends in the longitudinal direction of the target, and as a result, erosion is deeply formed at both ends in the longitudinal direction of the target as compared with the central portion of the target. There is no problem specific to the present invention. In addition, the shield plate 215 in the floating state of Comparative Example 3 prevents the sputtered material from adhering to the inner wall of the sputtering film forming chamber 224 as described above, and the sputtered material adhered to itself. It functions to clean.

(Comparative Example 4)
FIG. 11 is a cross-sectional view of the device of Comparative Example 4 (Patent Document 4). The apparatus of Comparative Example 4 is disposed so as to surround the chamber 302, the anode 305 and the cathode 303 disposed opposite to each other in the chamber 302, and the discharge region between the anode 305 and the cathode 303 in the chamber 302. In addition, an inner adhesion member 308 having a floating potential and an outer adhesion member 7 having the same potential as that of the chamber 302 disposed outside the inner adhesion member 308 in the chamber 302 are provided. In Patent Document 4, it is possible to prevent particles scattered by sputtering from adhering to the inner wall of the chamber, to prevent dielectric breakdown of the particles deposited on the adhesion preventing member, and to perform unnecessary plasma discharge in the chamber. The challenge is to prevent this. In the apparatus shown in FIG. 11, since the inner adhesion preventing member 308 is provided, it is possible to prevent the sputtered particles from adhering to the inner wall of the chamber. In addition, since the inner deposition preventing member 308 is set to a floating potential, even if electric charges are charged to the sputtered particles attached to the inner deposition preventing member 308, the dielectric breakdown does not occur. Therefore, generation of dust or particles can be prevented, and abnormal discharge such as arcing that occurs in the case of dielectric breakdown can be prevented.

  As described above, the apparatus of Comparative Example 4 is common to the film forming chamber 3 according to the present embodiment shown in FIG. 4 in that it includes the inner adhesion preventing member 308 having a floating potential and the target 303. . However, unlike the film formation chamber 3 shown in FIG. 4, the apparatus of Comparative Example 4 does not include the rectangular magnet unit 10, and therefore does not intend the subject of the present invention to improve the target utilization efficiency. Further, as described above, the inner adhesion preventing member 308 having the floating potential in the apparatus of Comparative Example 4 prevents the sputter particles from adhering to the inner wall of the chamber 302, and prevents the dielectric breakdown of the chamber itself. It functions to prevent unwanted plasma discharge in the interior.

(Comparative Example 5)
FIG. 12 is a cross-sectional view of the apparatus of Comparative Example 5 (Patent Document 5). The apparatus of Comparative Example 5 is disposed in the vicinity of the target 404 and has a first deposition shield 411 having a ground potential, a second deposition shield 412 that is disposed in the vicinity of the substrate 406 and has a floating potential, and a first A stable discharge anode 414 is provided outside the deposition shield 411, that is, outside the plasma discharge space, so as to always provide a stable ground potential surface. In the apparatus shown in FIG. 12, since the second deposition shield 412 is set at a floating potential, the dielectric breakdown is not caused by the charge accumulated on the film surface attached to the second deposition shield 412.

  As described above, the apparatus of Comparative Example 5 is related to the present embodiment shown in FIG. 4 in that the second deposition shield 412 is disposed near the substrate 406 at the floating potential and the target 404 is provided. Common with the film forming chamber 3. However, in the apparatus of Comparative Example 5, the first deposition shield 411 is arranged at the ground potential in the vicinity of the target 404 and the substrate 406 is at the floating potential. Therefore, unlike the film formation chamber shown in FIG. And plasma cannot be concentrated between the substrate 406 and the substrate 406. Furthermore, since electrons in the plasma also flow into the first deposition shield 411 disposed at the ground potential, erosion formed at both ends in the longitudinal direction of the target 404 cannot be reduced. Further, the second deposition shield 412 having the floating potential in the comparative example 5 functions to prevent its own dielectric breakdown.

(Comparative Example 6)
13 is a cross-sectional view of the device of Comparative Example 6, and FIG. 14 is a perspective view showing a schematic arrangement of the device of Comparative Example 6 (Patent Document 6). The apparatus of Comparative Example 6 aims to achieve uniform film formation and material utilization efficiency or film deposition efficiency improvement, and to realize material cost reduction and productivity improvement. Since the apparatus of Comparative Example 6 assumes that a sputter film is formed on a glass substrate that is an insulator, it is difficult to discharge in the glass substrate region. Therefore, there is a problem that electrons in the plasma ring avoid the glass substrate and flow into the mask member at the ground potential, causing plasma concentration at the end. The apparatus of Comparative Example 6 is intended to solve this problem. It has been proposed. That is, the apparatus of Comparative Example 6 is not assumed to be used by forming a film on a metal substrate. In the apparatus of Comparative Example 6, in order to achieve the above object, a region facing the both ends in the longitudinal direction of the magnetic circuit unit 501 of the mask member 504 adjacent to the glass substrate 505 is insulated from the ground potential by a certain width X. Thus, the floating region 504a is obtained. In addition, a rectangular target 502 is disposed with one surface facing the glass substrate 505 and the mask member 504, and five magnetic circuit units 501 are disposed on the other surface of the target 502.

  As described above, the apparatus of Comparative Example 6 is shown in FIG. 4 in that the rectangular target 502 is disposed and the area near the both ends in the longitudinal direction of the magnetic circuit unit 501 is the floating area 504a. Common with the deposition chamber. However, in the apparatus of Comparative Example 6, the floating region 504a prevents electrons from flowing into the end portion, and as a result, it is possible to suppress the concentration of plasma at the end portion. Therefore, as the film deposition on the floating region 504a progresses, the floating region 504a becomes ground, electrons easily flow into the end portion, and it becomes impossible to suppress the concentration of plasma on the end portion. Not suitable for.

  On the other hand, the film forming apparatus 3 according to this embodiment shown in FIG. 4 is configured so that the grounded metal belt-like substrate 1 is continuously conveyed in the chamber, so that the target 19 is continuously sputtered. It faces the grounded metal strip substrate 1 which is not filmed. In addition, the film forming apparatus 3 shown in FIG. 4 can maintain the shield 15 at a floating potential at all times through the insulator 16 between the shield 15 and the grounded chamber 3 even when the film is deposited on the shield 15. Is possible. Therefore, the film forming apparatus shown in FIG. 4 can concentrate plasma between the target 19 and the substrate 1 while the substrate is continuously transferred into the chamber. Suitable.

Example 1
Using the apparatus according to the present embodiment shown in FIG. 4 and the apparatus according to Comparative Example 1 shown in FIG. 5, the erosion results of the metal target were compared.
The film formation conditions are all aluminum (Al) as a target, the internal pressure is 1.0 [Pa], the applied power to the target is 15 [kW], the voltage is 390 to 410 [V], and Ar is a process gas. Using gas, each was discharged for a long time, and the erosion shape was actually measured and compared. The magnet unit 10 was swung at a predetermined cycle. In Comparative Example 1, the target usage rate was 40%, while in Example 1, the target usage rate was 44%. In Example 1, the deepest part of the target erosion near the end of the magnet was shallower than in the comparative example. That is, in Example 1, the difference in erosion between the vicinity of the center of the target and the vicinity of the target end portion was smaller than that of Comparative Example 1, and as a result, the target utilization rate was improved by about 4%. From this, it is considered that by changing the grounded shield 18 to the shield 15 having a floating potential, the uneven distribution of plasma at both ends in the longitudinal direction of the plasma ring can be eliminated, and the utilization rate of the metal target is improved.

(Example 2)
The erosion results of the high resistance target were compared using the apparatus according to the present embodiment shown in FIG. 4 and the apparatus according to Comparative Example 1 shown in FIG. As for the film forming conditions, all are zinc oxide (ZnO) as a target, the internal pressure is 1.0 [Pa], the applied power to the target is 15 [kw], the voltage is 390 to 410 [V], and the process gas is Using Ar gas, each was discharged for a long time, and the erosion shape was actually measured and compared. The magnet unit 10 was swung at a predetermined cycle. Note that the high-resistance target here refers to all targets that cause a potential difference from the ground (ground) by being deposited on a grounded surface (for example, a shield). In Comparative Example 1, the target usage rate was 30%, while in Example 2, the target usage rate was 36%. That is, even in a high resistance target, in this embodiment, the erosion depth of the target near the end of the magnet is shallow. That is, since the difference in erosion between the vicinity of the center of the target and the vicinity of the end of the target is reduced, the target utilization rate is improved by about 6%. From this, it is considered that the uneven distribution of plasma at both ends in the longitudinal direction of the plasma ring can be eliminated by changing the grounded shield 18 to the shield 15 having the floating potential, and the utilization rate of the high resistance target is improved. . In this configuration, unlike the existing apparatus, the chamber and the shield are not used as the main ground. In other words, since the belt-like substrate 1 is used as the ground, a new ground surface is always maintained, so that the ground is not hidden by adhesion of the insulating film and the potential configuration does not change with time, and is stable for a long time. Can maintain a stable potential configuration.

  As described above, in the present embodiment, by providing the floating potential shield that shields the inner wall of the chamber, it is possible to prevent or reduce plasma diffusion at both ends in the longitudinal direction of the plasma ring, Target utilization can be improved. In this embodiment, the rectangular magnet unit 10 is reciprocated at a predetermined cycle. However, the target utilization rate can be improved even when the rectangular magnet unit 10 is fixed.

(Second Embodiment)
FIG. 6 is a schematic sectional side view of a continuous film forming apparatus according to the second embodiment of the present invention.
The continuous film forming apparatus of the present embodiment has basically the same configuration as the continuous film forming apparatus shown in FIG. 1, and the same reference numerals are given to the same structural members, and the detailed description thereof will be given. Omitted. In the present embodiment, on the ceiling wall of the film forming chamber 3, a cylindrical target is mounted, and a rotatable rotary cathode 40 is provided along the longitudinal direction of the strip substrate 1. Each rotary cathode 40 is provided with a voltage application unit 11. The voltage application unit 11 may apply a DC voltage or may apply a high frequency voltage. In this example, the rotary cathode 40 functions as a target holder. The film formation chamber 3 is provided with a gas introduction part (not shown) for introducing a process gas such as argon and an exhaust part (not shown) for exhausting the film formation chamber 3. Furthermore, the magnet units 10 are respectively arranged inside the rotary cathodes 40. The rotary cathode 40 is configured to be rotatable with respect to a rotation axis parallel to the width direction of the belt-like substrate 1. On the other hand, the magnet unit 10 is fixed so that the lines of magnetic force are directed toward the band-shaped substrate 1.

FIG. 7 is a transparent top view of the continuous film forming apparatus according to the second embodiment of the present invention.
As shown in FIG. 7, the longitudinal width of the rotary cathode 40 is designed to be longer than the river width of the strip substrate 1.

  8A and 8B are detailed explanatory views of the magnet unit 10 in the rotary cathode 40 according to the second embodiment of the present invention. As shown in FIGS. 8A and 8B, the magnet unit 10 includes a long central magnet 20b, a peripheral magnet 20a disposed around the central magnet 20b, and a yoke plate 21. The surfaces on the target side of the central magnet 20b and the surrounding magnet 20a have different polarities.

The preferred embodiments and examples of the present application have been described above with reference to the accompanying drawings, but the present invention is not limited to the embodiments and examples, and is understood from the description of the claims. It can be changed into various forms within the range.

Claims (6)

A sputtering apparatus for continuously transporting a grounded metal strip substrate in a chamber and performing sputtering on the strip substrate,
A target holder provided to face the belt-shaped substrate transported in the chamber, and for holding a target;
Voltage application means for generating plasma in the chamber by applying a voltage to the target holder;
A magnet unit that is disposed on the opposite side of the target holder from the surface on which the target is held, and has a long first magnet and a second magnet disposed so as to surround the first magnet. When,
A first shield that is provided between a wall surface of the chamber in a direction from the magnet unit toward the belt-shaped substrate and the belt-shaped substrate, and shields the wall surface from the plasma,
The sputtering apparatus, wherein the first shield has a floating potential. A second shield extending from the target holder toward the strip substrate, further comprising a second shield surrounding at least a region between the target holder and the strip substrate;
The sputtering apparatus according to claim 1, wherein the second shield has a floating potential. Between the first shield and the wall surface, provided at a position hidden from the plasma, further comprising a support portion for supporting the first shield,
The sputtering apparatus according to claim 1, wherein the support portion is an insulator.   The sputtering apparatus according to claim 1, further comprising a swinging unit that swings the magnet unit.   2. The sputtering apparatus according to claim 1, wherein the width of the erosion in the longitudinal direction of the target mounted on the target holder is larger than the width of the strip-shaped substrate. An unwinding roll in which the belt-like substrate is wound into a roll;
A winding roll that winds up the belt-like substrate;
The sputtering apparatus according to claim 1, wherein at least one of the unwinding roll and the winding roll is grounded.

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