Sputtering cathode, sputtering device, and method for producing film-formed body

Abstract

This sputtering cathode has a sputtering target having a tubular shape in which the cross-sectional shape thereof has a pair of long side sections facing each other, and an erosion surface facing inward. Using the sputtering target, while moving a body to be film-formed, which has a film formation region having a narrower width than the long side sections of the sputtering target, parallel to one end face of the sputtering target and at a constant speed in a direction perpendicular to the long side sections above a space surrounded by the sputtering target, discharge is performed such that a plasma circulating along the inner surface of the sputtering target is generated, and the inner surface of the long side sections of the sputtering target is sputtered by ions in the plasma generated by a sputtering gas to perform film formation in the film formation region of the body to be film-formed.

Claims

1. A sputtering device, comprising: an anode; and a sputtering cathode, comprising a hollow sputtering target with a rectangular interior region and having a rectangular tubular configuration that extends in a lengthwise direction with a rectangular cross-section taken transverse to the lengthwise direction, the sputtering target having an open end at each end thereof and comprising a) a pair of major side walls that extend in the lengthwise direction of the sputtering target and that oppose each other across the rectangular interior region of the sputtering target, with opposing inner surfaces of the major side walls constituting sputtering erosion surfaces; and b) a pair of short side walls that extend in the lengthwise direction of the sputtering target and that oppose each other across the rectangular interior region of the sputtering target, the pair of short side walls connecting the pair of major side walls such that the rectangular interior region of the sputtering target is bounded by and delimited by the pair of major side walls along long sides thereof and by the pair of short side walls along short sides thereof, each of the major side walls comprising a magnetic-field-generating assembly consisting of a pair of permanent-magnet units disposed near an outer surface of each major side wall of the sputtering target, wherein each magnetic-field-generating assembly comprises one permanent-magnet unit of the pair of permanent-magnet units disposed toward each open end of the sputtering target and with each of the permanent-magnet units having a north pole and a south pole, wherein 1) the north pole of a first permanent-magnet unit of the pair of permanent-magnet units faces toward the sputtering target and the south pole of said first permanent-magnet unit of the pair of permanent-magnet units faces away from the sputtering target and constitutes an away-facing pole of the first permanent-magnet unit; and 2) the south pole of a second permanent-magnet unit of the pair of permanent-magnet units faces toward the sputtering target and the north pole of said second permanent-magnet unit of the pair of permanent-magnet units faces away from the sputtering target and constitutes an away-facing pole of the second permanent-magnet unit; and a magnetically conductive yoke extending between and magnetically connecting the away-facing poles of the first and second permanent-magnet units; whereby a magnetic circuit is formed between each major side wall, the pair of permanent-magnet units, and the magnetically conductive yoke, the magnetic circuit extending from the north pole of said first permanent-magnet unit of the pair of permanent-magnet units; along longitudinally central portions of the major side wall to the south pole of said second permanent-magnet unit of the pair of permanent-magnet units; along said second permanent-magnet unit of the pair of permanent-magnet units to the north pole of said second permanent-magnet unit of the pair of permanent-magnet units; and along the magnetically conductive yoke back to the south pole of said first permanent-magnet unit of the pair of permanent-magnet units; wherein each magnetic-field-generating assembly provides a magnetic field constituted by lines of magnetic force extending between the north pole of said first permanent-magnet unit and the south pole of said second permanent-magnet unit, such that the first and second permanent-magnet units are oriented with like polarities opposing each other across the rectangular interior region of the sputtering target such that plasma formed during operation of the sputtering device is essentially confined to regions within the rectangular interior region of the sputtering target that are adjacent to the sputtering erosion surfaces, the plasma generated being limited to a vicinity of inner surfaces of the sputtering target; wherein the permanent-magnet units are positioned along a length of the sputtering target such that the lines of magnetic force generated by the magnetic circuit are restricted to the sputtering cathode; and wherein the anode is disposed near one of the open ends of the sputtering target.

2. The sputtering device according to claim 1, wherein the pair of major side walls are made from different materials relative to each other to provide different species of sputtering atoms, the sputtering device further comprising a moveable shield that is positioned near one of the open ends of the sputtering target exterior to the sputtering target, the moveable shield being arranged to move transverse to the lengthwise direction of the sputtering target to selectively permit the different species of sputtering atoms to reach a to-be-coated substrate.

3. The sputtering device according to claim 1, further comprising a shield disposed near the end of the sputtering target that is opposite to the end near which the anode is located, the shield being configured and disposed to limit emission of plasma-caused radiation out of the sputtering target from the open end near which the shield is disposed.

4. The sputtering device according to claim 3, wherein the anode and the shield are electrically connected to each other to be held at the same electrical potential relative to the sputtering cathode.

5. The sputtering device according to claim 1, wherein the first and second permanent-magnet units each encircle the sputtering target.

6. The sputtering device according to claim 1, wherein the anode is spaced away from the sputtering target in the lengthwise direction thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 A longitudinal cross-sectional view showing a sputtering device according to a first embodiment of the invention.

(2) FIG. 2 A plan view showing a sputtering cathode of the sputtering device according to the first embodiment of the invention.

(3) FIG. 3 A longitudinal cross-sectional view showing a state where a plasma is generated near the surface of the sputtering target in the sputtering device according to the first embodiment of the invention.

(4) FIG. 4 A plan view showing a state where the plasma is generated near the surface of the sputtering target in the sputtering device according to the first embodiment of the invention.

(5) FIG. 5 A longitudinal cross-sectional view showing a method for forming a thin film on a substrate by the sputtering device according to the first embodiment of the invention.

(6) FIG. 6 A longitudinal cross-sectional view showing the method for forming a thin film on the substrate by the sputtering device according to the first embodiment of the invention.

(7) FIG. 7 A longitudinal cross-sectional view showing the method for forming a thin film on the substrate by the sputtering device according to the first embodiment of the invention.

(8) FIG. 8 A longitudinal cross-sectional view showing the method for forming a thin film on the substrate by the sputtering device according to the first embodiment of the invention.

(9) FIG. 9 A plan view showing the structure of the sputtering cathode and the anode as an example of the sputtering device according to the first embodiment of the invention.

(10) FIG. 10 A plan view showing a sputtering device according to a third embodiment of the invention.

(11) FIG. 11 A longitudinal cross-sectional view showing a method for forming a thin film on a substrate by the sputtering device according to the third embodiment of the invention.

(12) FIG. 12 A longitudinal cross-sectional view showing the method for forming a thin film on the substrate by the sputtering device according to the third embodiment of the invention.

(13) FIG. 13 A longitudinal cross-sectional view showing the method for forming a thin film on the substrate by the sputtering device according to the third embodiment of the invention.

(14) FIG. 14 A longitudinal cross-sectional view showing the method for forming a thin film on the substrate by the sputtering device according to the third embodiment of the invention.

(15) FIG. 15 A longitudinal cross-sectional view showing a sputtering device according to a fourth embodiment of the invention.

(16) FIG. 16 A plan view showing a sputtering cathode of a sputtering device according to a fifth embodiment of the invention.

(17) FIG. 17A A front view showing a film formation roller used in a sputtering device according to a sixth embodiment of the invention.

(18) FIG. 17B A left side view showing the film formation roller used in the sputtering device according to the sixth embodiment of the invention.

(19) FIG. 17C A right side view showing the film formation roller used in the sputtering device according to the sixth embodiment of the invention.

(20) FIG. 17D A longitudinal cross-sectional view showing the film formation roller used in the sputtering device according to the sixth embodiment of the invention.

(21) FIG. 18A A plan view showing a state where a cylindrical section of the film formation roller used in the sputtering device according to the sixth embodiment of the invention is expanded in a plane.

(22) FIG. 18B A cross-sectional view along the B-B line of FIG. 18A.

(23) FIG. 19A A plan view for explaining a method for making the film formation roller used in the sputtering device according to the sixth embodiment of the invention.

(24) FIG. 19B A cross-sectional view along the B-B line of FIG. 19A.

(25) FIG. 20A A plan view for explaining the method for making the film formation roller used in the sputtering device according to the sixth embodiment of the invention.

(26) FIG. 20B A cross-sectional view along the B-B line of FIG. 20A.

(27) FIG. 21A A plan view for explaining the method for making the film formation roller used in the sputtering device according to the sixth embodiment of the invention.

(28) FIG. 21B A cross-sectional view along the B-B line of FIG. 21A.

(29) FIG. 22 A schematic view showing the sputtering device according to the sixth embodiment of the invention.

(30) FIG. 23 A schematic view showing the sputtering device according to the sixth embodiment of the invention.

MODES FOR CARRYING OUT THE INVENTION

(31) Modes for carrying out the invention (hereinafter referred as embodiments) will now be explained below.

The First Embodiment

(32) [Sputtering Device]

(33) FIG. 1 and FIG. 2 are a longitudinal cross-sectional view and a plan view showing the sputtering device according to the first embodiment and show construction around a sputtering cathode and an anode disposed inside a vacuum chamber of the sputtering device. FIG. 1 is a cross-sectional view along the line 1-1 of FIG. 2.

(34) As shown in FIG. 1 and FIG. 2, the sputtering device comprises a sputtering target 10 having a rectangular tubular shape in which the cross-sectional shape thereof is a rectangular, and an erosion surface faces inward, a permanent magnet 20 disposed outside the sputtering target 10 and a yoke 30 disposed outside the permanent magnet 20. The sputtering target 10, the permanent magnet 20 and the yoke 30 form the sputtering cathode. The sputtering cathode is generally fixed to the vacuum chamber in an electrically isolated state. The permanent magnet 20 and the yoke 30 form a magnet circuit. Although polarity of the permanent magnet 20 is as shown in FIG. 1, opposite polarity may be used. A backing plate for cooling is preferably disposed between the sputtering target 10 and the permanent magnet 20, and for example cooling water is poured into a flow passage formed inside the backing plate. An anode 40 having an L-shaped cross-sectional shape is disposed near the lower end of a rectangular parallelepiped space surrounded by the sputtering target 10 such that the erosion surface of the sputtering target 10 is exposed. The anode 40 is generally connected with the vacuum chamber put to earth. A light stopping shield 50 having an L-shape cross-sectional shape is disposed near the upper end of the rectangular parallelpiped space surrounded by the sputtering target 10 such that the erosion surface of the sputtering target 10 is exposed. The light stopping shield 50 is made of electric conductor, typically metal. The light stopping shield 50 serves also as the anode and is generally connected with the vacuum chamber put to earth as the same as the anode 40.

(35) As shown in FIG. 2, when the distance between the pair of long side sections facing each other of the sputtering target 10 is denoted as a and the distance between the pair of short side sections facing each other of the sputtering target 10 is denoted as b, b/a is selected to be not less than 2, generally not larger than 40. a is generally selected to be not less than 50 mm and not larger than 150 mm.

(36) In the sputtering device, film formation is performed for a substrate A (a body to be film-formed) held by a prescribed carrying mechanism not illustrated above the space surrounded by the sputtering target 10. Film formation is performed while the substrate S is moved for the sputtering target 10 at a constant speed in the direction traversing the long side sections of the sputtering target 10. In FIG. 1, shown is as an example a case where the substrate S is moved at a constant speed parallel to the upper end surface of the sputtering target 10 in the direction perpendicular to the long side sections of the sputtering target 10. Width of a film formation region of the substrate S in the direction parallel to the long side sections of the sputtering target 10 is selected to be less than b, and therefore the substrate S is held between the pair of short side sections facing each other of the sputtering target 10 when film formation is performed. The width of the film formation region of the substrate S is equal to the width of the substrate S when film formation is performed on the whole surface of the substrate S. The substrate S may be basically anything and is not particularly limited. The substrate S may be a long film wound around a roller which is used for a roll-to-roll process.

(37) [Method for Forming a Film by the Sputtering Device]

(38) After the vacuum chamber is evacuated to high vacuum by vacuum pumps, an Ar gas is introduced into the space surrounded by the sputtering target 10 as a sputtering gas. Thereafter, high voltage, generally DC high voltage necessary to generate a plasm is applied between the anode 40 and the sputtering cathode by a prescribed power source. Generally, the anode 40 is put to earth and negative high voltage (for example, 400V) is applied to the sputtering cathode. With this, as shown in FIG. 3 and FIG. 4, a plasma 60 circulating along the inner surface of the sputtering target 10 is generated near the surface of the sputtering target 10.

(39) Before film formation, the substrate S is located far from a position above the space surrounded by the sputtering target 10.

(40) The sputtering target 10 is sputtered by Ar ions in the plasma 60 circulating along the inner surface of the sputtering target 10. As a result, atoms constituting the sputtering target 10 are emitted upward from the space surrounded by the sputtering target 10. In this case, although atoms are emitted from everywhere near the plasma 60 of the erosion surface of the sputtering target 10, atoms emitted from the erosion surface of the short side sections of the sputtering target 10 are not basically used for film formation. A way to accomplish this is to prevent atoms emitted from the erosion surface of the short side sections of the sputtering target 10 from reaching the substrate S during film formation by disposing a horizontal shield plate above the sputtering target 10 so as to shield both ends of the sputtering target 10 in the long side direction. Alternatively, it is possible to prevent atoms emitted from the erosion surface of the short side sections of the sputtering target 10 from reaching the substrate S during film formation by setting the width b of the sputtering target 10 in the longitudinal direction sufficiently larger than the width of the substrate S. A part of the atoms emitted from the sputtering target 10 is shielded by the light stopping shield 50. As a result, beams of sputtered particles 70 and 80 shown in FIG. 5 are obtained from the erosion surface of the long side sections of the sputtering target 10. The beams of sputtered particles 70 and 80 have a nearly uniform intensity distribution in the longitudinal direction of the sputtering target 10.

(41) When the stable beams of sputtered particles 70 and 80 are obtained, film formation is performed by the beams of sputtered particles 70 and 80 while the substrate S is moved for the sputtering target 10 at a constant speed in the direction traversing the long side sections of the sputtering target 10. When the substrate S is moved toward a position above the space surrounded by the sputtering target 10, the beam of sputtered particles 70 first irradiates the substrate S to begin film formation. FIG. 6 shows a state when the front of the substrate S just reaches a position above the center of the space surrounded by the sputtering target 10. At this time, the beam of sputtered particles 80 does not contribute to film formation. When the substrate S is moved further and the beam of sputtered particles 80 begins to irradiate the substrate S, the beam of sputtered particles 80 begins to contriubute film formation in addition to the beam of sputtered particles 70. FIG. 7 shows a state when the substrate S is moved to a position just above the space surrounded by the sputtering target 10. As shown in FIG. 7, the beams of sputtered particles 70 and 80 irradiate the substrate S to perform film formation. The substrate S is moved further while film formation is performed in this way. And as shown in FIG. 8, the substrate S is moved to a place far from the position above the space surrounded by the sputtering target 10 where the beams of sputtered particles 70 and 80 do not irradiate the substrate S. In this way, a thin film F is formed on the substrate S.

(42) [Example of the Sputtering Cathode and the Anode of the Sputtering Device]

(43) As shown in FIG. 9, the sputtering target 10 is formed by four boardlike sputtering targets 10a, 10b, 10c and 10d, the permanent magnet 20 is formed by four boardlike or rodlike permanent magnets 20a, 20b, 20c and 20d and the yoke 30 is formed by four boardlike yokes 30a, 30b, 30c and 30d. Backing plates 90a, 90b, 90c and 90d are inserted between the sputtering targets 10a, 10b, 10c and 10d and the permanent magnets 20a, 20b, 20c and 20d, respectively. The distance between the sputtering target 10a and the sputtering target 10c is set to 80 mm, the distance between the sputtering target 10b and the sputtering target 10d is set to 200 mm and the heights of the sputtering targets 10a, 10b, 10c and 10d are set to 80 mm.

(44) Four boardlike anodes 100a, 100b, 100c and 100d are formed outside the yokes 30a, 30b, 30c and 30d. The anodes 100a, 100b, 100c and 100d are connected to the vacuum chamber put to earth together with the anode 40.

(45) As described above, according to the first embodiment, since the sputtering cathode has the sputtering target 10 having a rectangular tubular shape in which the cross-sectional shape thereof is a rectangular, and the erosion surface thereof faces inward, various advantages can be obtained as follows. That is, it is possible to generate the plasma 60 circulating along the inner surface of the sputtering target 10 on the side of the erosion surface of the sputtering target 10. Therefore, it is possible to increase the density of the plasma 60 to increase the rate of film formation sufficiently. Furthermore, the place where plenty of the plasma 60 is generated is limited near the surface of the sputtering target 10. In addition to this, the light stopping shield 50 is disposed. With this, it is possible to lower the risk of causing damage to the substrate S by irradiation of light generated from the plasma 60 to a minimum. Lines of magnetic force generated by the magnetic circuit formed by the permanent magnet 20 and the yoke 30 are restricted to the sputtering cathode and not bound for the substrate S. Therefore, there is no risk of causing damage to the substrate S by the plasma 60 and an electron beam. Since film formation is performed by using the beams of sputtered particles 70 and 80 obtained from the long side sections facing each other of the sputtering target 10, it is possible to lower the risk of causing damage to the substrate S by bombardment of high energy particles of reflected sputtering neutral gases. Furthermore, the beams of sputtered particles 70 and 80 obtained from the long side sections facing each other of the sputtering target 10 have a uniform intensity distribution in the direction parallel to the long side sections. In addition to this, film formation is performed while the substrate S is moved at a constant speed in the direction traversing the long side sections, for example the direction perpendicular to the long side sections. Therefore, it is possible to reduce uneveness of the thickness of the thin film F formed on the substrate S. For example, thickness distribution of the thin film F can be controlled within 5%. The sputtering device is preferably applied to film formation of electrode materials in various devices such as semiconductor devices, solar batteries, liquid crystal displays, organic EL displays.

The Second Embodiment

(46) [Sputtering Device]

(47) In the sputtering device, the sputtering target 10 comprises the sputtering targets 10a, 10b, 10c and 10d shown in FIG. 9. Here, the sputtering targets 10a and 10b forming the long side sections facing each other are made of materials different from each other. Other construction of the sputtering device is as the same as the sputtering device according to the first embodiment.

(48) [Method for Forming a Film by the Sputtering Device>

(49) As the same as the first embodiment, film formation is performed in the film formation region of the substrate S by using the beams of sputtered particles 70 and 80. In this case, since the sputtering targets 10a and 10b are made of materials different from each other, constituent atoms of the beam of sputtered particles 70 and constituent atoms of the beam of sputtered particles 80 are different from each other. Therefore, the thin film F formed on the substrate S has the composition in which constituent atoms of the beam of sputtered particles 70 and constituent atoms of the beam of sputtered particles 80 are mixed, in other words, almost the composition in which constitutent atoms of the material forming the sputtering target 10a and constituent atoms of the material forming the sputtering target 10c are mixed.

(50) According to the second embodiment, it is possible to obtain further advantage that it is possible to form the thin film F having the composition in which the constituent atoms of the material forming the sputtering target 10a and the constituent atoms of the material forming the sputtering target 10c are mixed. Therefore, for example, by forming the sputtering target 10a by titanium having the function of improving adhesiveness of a thin film and by forming the sputtering target 10c by another metal, it is possible to form the thin film F having the composition in which titanium and another metal are mixed to obtain the thin film F having excellent cohesiveness for the substrate S.

The Third Embodiment

(51) [Sputtering Device]

(52) FIG. 10 shows the sputtering device according to the third embodiment. In the sputtering device, as the same as the sputtering device according to the second embodiment, the sputtering target 10 comprises the sputtering targets 10a, 10b, 10c and 10d shown in FIG. 9, the sputtering targets 10a and 10c of the long side sections facing each other being made of materials different from each other. In addition, as shown in FIG. 10, in the sputtering device, a horizontal shield plate 90 held by a carrying mechanism not illustrated can be placed at a height between the height of the substrate S and the height of the light stopping shield 50 so as to stop the beam of sputtered particles 80 from the sputtering target 10c or the beam of sputtered particles 70 from the sputtering target 10a. Other construction of the sputtering device is as the same as the sputtering device according to the first embodiment.

(53) [Method for Forming a Film by the Sputtering Device]

(54) For example, in order to form a thin film on the substrate S by only the beam of sputtered particles 70, the horizontal shield plate 90 is first moved to a position shown by an alternate long and short dashes line in FIG. 10. At this moment, the beam of sputtered particles 80 is stopped by the horizontal shield plate 90. In this state, film formation is performed in the film formation region of the substrate S by using only the beam of sputtered particles 70 as shown in FIG. 11 while the substrate S is moved in the direction shown by an arrow in FIG. 10. As shown in FIG. 12, the sutstrate S is moved to a position far from the position above the space surrounded by the sputtering targets 10a, 10b, 10c and 10d. In this way, a thin film F.sub.1 is formed. The thin film F.sub.1 is composed of constituent atoms of the beam of sputtered particles 70, almost constituent atoms of the material forming the sputtering target 10a. Next, the horizontal shield plate 90 is moved to a position shown by an alternate long and two short dashes line where the beam of sputtered particles 70 is stopped as shown in FIG. 10. In this state, as shown in FIG. 13, film formation is performed in the film formation region of the substrate S by using only the beam of sputtered particles 80 while the substrate S is moved in the direction opposite to the direction shown by the arrow in FIG. 10. As shown in FIG. 14, the substrate S is moved to a position far from the position above the space surrounded by the sputtering targets 10a, 10b, 10c and 10d. In this way, a thin film F.sub.2 is formed on the thin film F.sub.1. The thin film F.sub.2 is composed of constituent atoms of the beam of sputtered particles 80, almost constituent atoms of the material forming the sputtering target 10c. Thus, it is possible to form the two-layer film made of the thin film F.sub.1 and the thin film F.sub.2 having compositions different from each other.

(55) In order to prevent constituent atoms of the thin film F.sub.1 from containing constituent atoms of the material forming the sputtering target 10c and on the contrary in order to prevent constituent atoms of the thin film F.sub.2 from containing constituent atoms of the material forming the sputtering target 10a, for example, as shown in FIG. 10, a vertical shield plate 100 may be inserted into the central part of the space between the sputtering target 10a and the sputtering target 10c to prevent constituent atoms of the material forming the sputtering target 10c from mixing with the beam of sputtered particles 70 and to prevent constituent atoms of the material forming the sputtering target 10a from mixing with the beam of sputtered particles 80. One of the characteristics of the sputtering cathode is that the vertical shield plate 100 can be inserted in this way. That is, in the sputtering cathode, the plasma 60 circulates near the surface of the four boardlike sputtering targets 10a, 10b, 10c and 10d and the plasma 60 is not generated in the central part of the space between the sputtering target 10a and the sputtering target 10c. A shield plate inclined to the vertical direction may be used instead of the vertical shield plate 100.

(56) According to the third embodiment, in addition to the same advantages as the first embodiment, it is possible to obtain further advantage that it is possible to form the two-layer film made of the thin film F.sub.1 and the thin film F.sub.2 having compositions different from each other. Therefore, for example, by forming the sputtering target 10a from titanium having the function of improving adhesiveness of a thin film and forming the sputtering target 10c from another metal, it is possible to form first the thin film F.sub.1 composed of titanium having excellent adhesiveness for the substrate S and then form the thin film F.sub.2 composed of another metal thereon to obtain the two-layer film made of the thin film F.sub.1 having excellent adhesiveness for the substrate S and the thin film F.sub.2.

The Fourth Embodiment

(57) [Sputtering Device]

(58) The sputtering device according to the fourth embodiment has basically the same structure as the sputtering device according to the first embodiment. In the first embodiment, film formation is performed by using the beams of sputtered particles 70 and 80 taken out over the space surrounded by the sputtering target 10 while the substrate S is moved. In the fourth embodiment, in addition to this, as shown in FIG. 15, film formation is performed on another substrate by using beams of sputtered particles 70 and 80 taken out below the space surrounded by the sputtering target 10 from the long side sections facing each other of the sputtering target 10. Here, in the sputtering device, for example, by fixing the sputtering cathode and the anode 40 to the inner surface of the sidewall of the vacuum chamber, it is possible to secure space for film formation below the space surrounded by the sputtering target 10.

(59) [Method for Forming a Film by the Sputtering Device]

(60) As shown in FIG. 15, the beams of sputtered particles 70 and 80 are taken above the space surrounded by the sputtering target 10 and at the same time the beams of sputtered particles 70 and 80 are taken below the space surrounded by the sputtering target 10. Film formation is performed on the substrate S by using the beams of sputtered particles 70 and 80 above the space surrounded by the sputtering target 10 while the substrate S is moved for the sputtering target 10 in the direction traversing the long side sections of the sputtering target 10. At the same time, film formation is performed on the substrate S by using the beams of sputtered particles 70 abd 80 below the space surrounded by the sputtering target 10 while the substrate S is moved for the sputtering target 10 in the direction traversing the long side sections of the sputtering target 10. That is, it is possible to perform film formation on the substrate S above the space surrounded by the sputtering target 10 and perform at the same time film formation on the substrate S below the space surrounded by the sputtering target 10.

(61) According to the fourth embodiment, in addition to the same advantages as the first embodiment, it is possible to obtain further advantage that it is possible to increase productivity markedly because film formation can be performed on the two substrates S and S at the same time.

The Fifth Embodiment

(62) [Sputtering Device]

(63) The sputtering device according to the fifth embodiment differs from the sputtering device according to the first embodiment in that the sputtering target 10 shown in FIG. 16 is used. That is, as shown in FIG. 16, the sputtering target 10 comprises a pair of long side sections facing parallel each other and semicircular sections connected to the long side sections. The permanent magnet 20 disposed outside the sputtering target 10 and the yoke 30 disposed outside the permanent magnet 20 have the same shape as the sputtering target 10. Other construction of the sputtering device is the same as the sputtering device according to the first embodiment.

(64) [Method for Forming a Film by the Sputtering Device]

(65) The method for forming a film by the sputtering device is the same as the first embodiment.

(66) According to the fifth embodiment, it is possible to obtain the same advantages as the first embodiment.

The Sixth Embodiment

(67) [Sputtering Device]

(68) The sputtering device according to the sixth embodiment is a sputtering device in which film formation is performed by a roll-to-roll method and differs from the sputtering device according to the first embodiment in that the film formation roller shown in FIG. 17A, FIG. 17B, FIG. 17C and FIG. 17D is used as the film formation roller around which a body to be film-formed is wound. Here, FIG. 17A is a front view, FIG. 17B is a left side view, FIG. 17C is a right side view and FIG. 17D is a longitudinal cross-sectional view.

(69) As shown in FIG. 17A, FIG. 17B, FIG. 17C and FIG. 17D, the film formation roller comprises a cylindrical section 210, circular boards 220 and 230 attached to both ends of the cylindrical section 210 such as to close the cylindrical section 210, and a shaft 240 disposed on the central axis of the film formation roller, therefore the cylindrical section 210 outside the circular boards 220 and 230.

(70) The cylindrical section 210 has a built-in flow passage 211 having the rectangular cross-sectional shape parallel to the central axis of the cylindrical section 210. That is, the flow passage 211 is buried in the cylindrical section 210. FIG. 18A is a plan view in a state in which the cylindrical section 210 is expanded in a plane and FIG. 18B is a cross-sectional view along the B-B line of FIG. 18A. As shown in FIG. 18A and FIG. 18B, in the example, the shape when the cylindrical section 210 is expanded in a plane is a rectangular and the flow passage 211 has a linear section 211a elongating parallel to long sides of the rectangle and a turn back section 211b folded vertical to the linear section 211a, which are provided alternately, and has a zigzag folded shape. A hole 212 serving as an inlet of fluid such as cooling water is formed on one end of the flow passage 211 and a hole 213 serving as an outlet of fluid is formed on the other end thereof. The cylindrical section 210 is made of copper, copper alloy, aluminum or aluminum alloy, preferably made of oxygen free copper having the highest thermal conductivity among these materials. Thermal conductivity of oxygen free copper is about twenty three times higher than that of stainless steel (SUS304), for example. Although not illustrated, hard chromium plating is formed on at least the outer peripheral surface, typically the outer peripheral surface and the inner peripheral surface of the cylindrical section 210. If the hard chromium plating layer is too thick, thermal conductivity of the cylindrical section 210 decreases. If the hard chromium plating layer is too thin, effect of surface hardening of the cylindrical section 210 is little. Therefore, the thickness of the hard chromium plating layer is generally selected to be not less than 20 m and not larger than 40 m, for example 30 m. Hardness of the hard chromium plating layer may be, for example, not less than 500 in Vickers hardness. If necessary, the surface of the hard chromium plating layer is flattened by polishing to decrease surface roughness R.sub.a drastically, for example, to about 10 nm.

(71) The circular boards 220 and 230 are fixed to both ends of the cylindrical section 210 by bolting, welding, etc. Four circular throughholes 221 to 224 are formed in the circular board 220 every 90 around the central axis. Similarly, four circular throughholes 231 to 234 are formed in the circular board 230 every 90 around the central axis at positions corresponding to the throughholes 221 to 224 of the circular board 220. The throughholes 221 to 224 and 231 to 234 are formed so that when the film formation roller is installed in the vacuum chamber of the sputtering device and the vacuum chamber is evacuated, pressure difference between the inside and the outside of the cylindrical section 210 is eliminated to prevent external force resulting from the pressure difference from applying to the cylindrical section 210 and the circular boards 220 and 230. Diameters of the throughholes 221 to 224 and 231 to 234 are appropriately selected so as to obtain mechanical strength of the circular boards 220 and 230. The circular boards 220 and 230 are made of, for example, stainless steel.

(72) A throughhole 241 having the circular cross-sectional shape is formed on the central axis of the shaft 240 fixed to the circular board 220. The throughhole 241 comprises a section 241a having the diameter d.sub.1 extending from the front end of the shaft 240 to an intermediate depth position and a section 241b having the diameter d.sub.2 smaller than d.sub.1 extending from the intermediate depth position to the circular board 220. A throughhole 225 communicating with the section 241b is formed in the circular board 220 on the central axis of the shaft 240. One end of a pipe 251 is hermetically fixed such as to communicate with the throughhole 225. The other end of the pipe 251 is connected with the hole 212 formed on the end of the flow passage 211 on the side of the circular board 220. Similarly, a throughhole 242 having the circular cross-sectional shape is formed on the central axis of the shaft 240 fixed to the circular board 230. The throughhole 242 comprises a section 242a having the diameter d.sub.1 extending from the front end of the shaft 240 to an intermediate depth position and a section 242b having the diatemer d.sub.2 smaller than d.sub.1 extending from the intermediate depth position to the circular board 230. A throughhole 235 communicating with the section 242b is formed in the circular board 230 on the central axis of the shaft 240. One end of a pipe 252 is hermetically fixed such as to communicate with the throughhole 235. The other end of the pipe 252 is connected with the hole 213 formed on the end of the flow passage 211 on the side of the circular board 230. A flexible metal pipe, for example, a bellows pipe is preferably used as the pipes 250 and 251. Fluid is supplied from, for example, the throughhole 241 of the shaft 240 fixed to the circular board 220 by a fluid circulation mechanism not illustrated, poured into the flow passage 211 from the hole 212 of the cylindrical section 210 through the pipe 251, ejected from the hole 231 through the flow passage 211, ejected from the throughhole 242 of the shaft 240 fixed to the circular board 230 through the pipe 252 and circulated in the path.

(73) Size of each section of the film formation roller is appropriately selected. Sizes are exemplified as the total length of 500 mm, diameter of 400 mm, thickness of the cylindrical section 210 of 10 mm, cross section of the flow passage 211 of 35 mm5 mm and interval of the flow passage 211 of 15 mm.

(74) The film formation roller can be made as follows, for example.

(75) As shown in FIG. 19A and FIG. 19B, prepared is a rectangular flat board 260 having the same planar shape as the one shown in the expansion plan of the cylindrical section 210 shown in FIG. 18A and FIG. 18B. Here, FIG. 19A is a plan view and FIG. 19B is a cross-sectional view along the B-B line in FIG. 19A. The thickness of the flat board 260 is the same as the thickness of the cylindrical section 210. A groove 26 having the cross-sectional shape with a step is formed on one major plane of the flat board 260. A lower groove 261a of the groove 261 has the same planar shape and depth as the flow passage 211 when the cylindrical section 210 is expanded in a plane. An upper groove 261b of the groove 261 has a planar shape which is similar to the lower groove 261 and a size larger. The flat board 260 has a hole 212 formed in the bottom of one end of the lower groove 261a of the groove 261 and a hole 213 formed in the bottom of the other end of the lower groove 261a of the groove 261.

(76) Next, as shown in FIG. 20A and FIG. 20B, prepared is a flat board 270 having the same planar shape as the upper groove 261b of the groove 261 of the flat board 260 and the thickness as the same as the depth of the upper groove 261b. Here, FIG. 20A is a plan view and FIG. 20B is a cross-sectional view along the B-B line of FIG. 20A.

(77) Next, as shown in FIG. 21A and FIG. 21B, the flat board 270 is fitted to the upper groove 261b of the groove 261 of the flat board 260. Here, FIG. 21A is a plan view and FIG. 21B is a cross-sectional view along the B-B line of FIG. 21A.

(78) Next, the boundary section (the linear section and the turn back section) between the flat board 260 and the flat board 270 shown in FIG. 21A and FIG. 21B is joined by friction stir welding. In this way, obtained is a rectangular flat board 280 in which the lower groove 261a of the groove 261 serving as the flow passage 211 is formed between the flat board 260 and the flat board 270.

(79) Next, the flat board 280 is rounded in its longitudinal direction such that the surface of the flat board 280 on which friction stir welding was performed faces outward, one short side and the other short side of the board rounded like a cylinder are made contact with each other and jointed by friction stir welding. In this way, made is the cylindrical section 210 having the built-in flow passage 211 formed by the lower groove 261a of the groove 261 of the flat board 260.

(80) Thereafter, the circular boards 220 and 230 and the shaft 240 are fixed to both ends of the cylindrical section 210.

(81) As described above, the target film formation roller shown in FIG. 17A, FIG. 17B, FIG. 17C and FIG. 17D is made.

(82) FIG. 22 and FIG. 23 show the sputtering device according to the sixth embodiment using the film formation roller shown in FIG. 17A, FIG. 17B, FIG. 17C and FIG. 17D. Here, FIG. 22 is a schematic view of the inside of the vacuum chamber of the sputtering device seen from a direction parallel to the film formation roller and FIG. 23 is a schematic view of the inside of the vacuum chamber of the sputtering device seen from a direction perpendicular to the film formation roller.

(83) As shown in FIG. 22 and FIG. 23, in the sputtering device, the inside of the vacuum chamber 290 is vertically partioned into two sections by a partion board 291. A lower space below the partion board 291 of the inside of the vacuum chamber 290 is a film formation room C.sub.1 and an upper space above the partion board 291 thereof is a film carrying room C.sub.2. The film formation roller shown in FIG. 17A, FIG. 17B, FIG. 17C and FIG. 17D is disposed horizontally inside the film formation room C.sub.1 as a film formation roller R.sub.1. Both ends of the shaft 240 on both ends of the cylindrical section 210 of the film formation roller R.sub.1 are inserted into a circular hole formed in support boards 292 and 293 fixed to both sidewalls of the film formation room C.sub.1 and a circular hole formed in the both sidewalls of the film formation room C.sub.1 and are rotatably supported by these holes. For example, three sputtering cathodes K.sub.1, K.sub.2 and K.sub.3 are disposed on the inner wall of the film formation room C.sub.1. Among them, the sputtering cathode K.sub.1 is disposed on the bottom of the film formation room C.sub.1 through an insulating member 294 and electrically isolated from the vacuum chamber 290. The sputtering cathodes K.sub.2 and K.sub.3 are disposed on sidewalls facing each other of the film formation room C.sub.1 through the insulating member 294, respectively. The sputtering cathodes K.sub.1, K.sub.2 and K.sub.3 may have the similar structure or different structures, but at least the sputtering cathode K.sub.1 has the same structure as the first embodiment. A shield plate 295 is disposed around the cylindrical section 210 of the film formation roller R.sub.1 to limit beams of sputtered particles generated from the sputtering cathodes K.sub.1, K.sub.2 and K.sub.3 and irradiated a film when film formation is performed on a film. On the other hand, rollers R.sub.2 and R.sub.3 for unwinding/winding and carrying rollers (or guide rollers) R.sub.4, R.sub.5, R.sub.6 and R.sub.7 are disposed in the film carrying room C.sub.2. Axes of the rollers R.sub.2 and R.sub.3 for unwinding/winding (only an axis S.sub.3 of the roller R.sub.3 is illustrated in FIG. 23) are inserted into a circular hole formed in the support boards 292 and 293 fixed to both sidewalls of the film formation room C.sub.1 and a circular hole formed in the both sidewalls of the film formation room C.sub.1 and are rotatably supported by these holes. Axes of the carrying rollers R.sub.4, R.sub.5, R.sub.6 and R.sub.7 (only axes S.sub.6 and S.sub.7 of the carrying rollers R.sub.6 and R.sub.7 are illustrated in FIG. 23) are rotatably supported by circular holes formed in the support boards 292 and 293. A film 300 is carried by the roller R.sub.2 for unwinding/winding, the carrying rollers R.sub.4 and R.sub.5, the film formation roller R.sub.1, the carrying rollers R.sub.6 and R.sub.7 and the roller R.sub.3 for unwinding/winding. The film 300 can be carried by rotating the rollers R.sub.2 and R.sub.3 by a rotation mechanism not illustrated which is fixed to the shafts S.sub.2 and S.sub.3 of the rollers R.sub.2 and R.sub.3. In this case, by rotating the rollers R.sub.2 and R.sub.3 counterclockwise in FIG. 22, the film 300 can be unwinded from the roller R.sub.2, carried through the carrying rollers R.sub.4 and R.sub.5, the film formation roller R.sub.1 and the carrying rollers R.sub.6 and R.sub.7 and wound by the roller R.sub.3. In contrast to this, by rotating the rollers R.sub.2 and R.sub.3 clockwise in FIG. 22, the film 300 can be unwound from the roller R.sub.3, carried through the carrying rollers R.sub.7 and R.sub.6, the film formation roller R.sub.1 and the carrying rollers R.sub.5 and R.sub.4 and wound by the roller R.sub.2. That is, the film 300 can be carried in opposite directions. With this, for example, film formation is performed on the film formation roller R.sub.1 while the film 300 is carried by rotating the rollers R.sub.2 and R.sub.3 counterclockwise in FIG. 22, and thereafter film formation is performed on the film formation roller R.sub.1 while the film 300 is carried reversely by rotating the rollers R.sub.2 and R.sub.3 clockwise in FIG. 22. By repeating such film formation several times, a multi-layer thin film can be formed on the film 300. If necessary, at least one of the carrying rollers R.sub.4 to R.sub.7 may be constituted as the same as the film formation roller R.sub.1 and used as a cooling roller. With this, the film 300 heated during film formation on the film formation roller R.sub.1 can be cooled by the cooling roller while the film 300 is carried before the film 300 is wound by the roller R.sub.2 or the roller R.sub.3. Therefore, it is possible to prevent the problem of abrasion formed by mutual rubbing of the film 300 when the film 300 is cooled to shrink after the film 300 is wound by the roller R.sub.2 or the roller R.sub.3 at a high temperature. Slitlike holes 291a and 291b are formed in the partion board 291 to pass the film 300.

(84) In the sputtering device, film formation is performed above the space surrounded by the sputtering target 10 while the film 300 wound around the cylindrical section 210 of the film formation roller R.sub.1 is carried. In this case, the film 300 is carried for the sputtering target 10 in the direction traversing the long side sections of the sputtering target 10. The width of the film formation region of the film 300 in the direction parallel to the long side sections of the sputtering target 10 is selected to be less than b, and therefore the film 300 is held between the pair of short side sections facing each other of the sputtering target 10. The width of the film formation region is equal to the width of the film 300 when film formation is performed on the whole surface of the film 300.

(85) [Method for Forming a Film by the Sputtering Device]

(86) Although it is possible to perform film formation using two or more of the sputtering cathodes K.sub.1, K.sub.2 and K.sub.3, described here is a case where film formation is performed by using only the sputtering cathode K.sub.1.

(87) Water is circulated through the flow passage 211 of the cylindrical section 210 of the film formation roller R.sub.1 and temperature of the cylindrical section 210 is set to a temperature at which film formation is performed on the film 300. If necessary, an antifreeze solution such as ethylene glycol etc. is added to water circulated in the flow passage 211. An example of a control range of temperature of water circulated in the flow passage 211 is 10 C.80 C.

(88) The vacuum chamber 290 is evacuated to high vacuum by vacuum pumps, thereafter an Ar gas is introduced into the space surrounded by the sputtering target 10 as a sputtering gas and generally DC high voltage necessary to generate plasma is applied between the anode 40 and the sputtering cathode K.sub.1 by a prescribed power source. Generally, the anode 40 is put to earth and negative high voltage (for example, 400V) is applied to the sputtering cathode K.sub.1. With this, as shown in FIG. 3 and FIG. 4, the plasma 60 circulating along the inner surface of the sputtering target 10 is generated near the surface of the sputtering target 10.

(89) The sputtering target 10 is sputtered by Ar ions in the plasma 60 circulating along the inner surface of the sputtering target 10. As a result, atoms constituting the sputtering target 10 are emitted upward from the space surrounded by the sputtering target 10. In this case, although atoms are emitted from everywhere near the plasma 60 of the erosion surface of the sputtering target 10, atoms emitted from the erosion surface of the short side sections of the sputtering target 10 are not basically used for film formation. To accomplish this, a horizontal shield plate may be disposed above the sputtering target 10 so as to shield both ends in the long side direction of the sputtering target 10, so that it is possible to prevent atoms emitted from the erosion surface of the short side sections of the sputtering target 10 from reaching the film 300 during film formation. Altenatively, the width b in the longitudinal direction of the sputtering target 10 may be set to be much larger than the width of the film 300, so that it is possible to prevent atoms emitted from the erosion surface of the short side sections of the sputtering target 10 from reaching the film 300 during film formation. A part of atoms emitted from the sputtering target 10 is stopped by the light stopping shield 50. As a result, the beams of sputtered particles 70 and 80 shown in FIG. 5 are obtained from the erosion surface of the long side sections of the sputtering target 10. The beams of sputtered particles 70 and 80 have almost uniform intensity distribution in the longituducal direction of the sputtering target 10.

(90) When the stable beams of sputtered particles 70 and 80 are obtained, the rollers R.sub.2 and R.sub.3 for unwinding/winding the film 300 are rotated, for example, counterclockwise in FIG. 22, and film formation is performed on the film 300 wound around the film formation roller R.sub.1 from below by the beams of sputtered particles 70 and 80 while the film 300 is carried at a constant speed through the carrying rollers R.sub.4 and R.sub.5, the film formation roller R.sub.1 and the carrying rollers R.sub.6 and R.sub.7. In this case, tensional forces applied to the film 300 are controlled to be a constant value about 10100 Newton (N), for example.

(91) According to the sixth embodiment, since the cylindrical section 210 of the film formation roller R.sub.1 is made of copper, copper alloy, aluminum or aluminum alloy having excellent termal conductivity, it is possible to cool or heat promptly and efficiently the cylindrical section 210 around which the film 300 to be film-formed is wound by pouring fluid such as cooling water or warm water into the flow passage 211 built in the cylindrical section 210, and furthermore it is possible to avoid the problem of the conventional film formation roller described above that it is deformed like a beer barrel in vacuum. Therefore, when film formation is performed on the film 300 by a roll-to-roll method in the sputtering device, it is possible to carry the film 300 smoothly, keeping the surface of the film 300 flat. In addition, since thermal response of the cylindrical section 210 made of copper, copper alloy, aluminum or aluminum alloy having excellent thermal conductivity is good, it is possible to control temperature of the cylindrical section 210 promptly and accurately by temperature or flow rate of the fluid such as cooling water or warm water poured into the flow passage 211, and therefore it is possible to control temperature of the film 300 wound around the cylindrical section 210 promptly and accurately, resulting good film formation on the film 300.

(92) Heretofore, embodiments and examples of the present invention have been explained specifically. However, the present invention is not limited to these embodiments and examples, but contemplates various changes and modifications based on the technical idea of the present invention.

(93) For example, numerical numbers, materials, structures, shapes, etc. presented in the aforementioned embodiments and examples are only examples, and the different numerical numbers, materials, structures, shapes, etc. may be used as necessary.

EXPLANATION OF REFERENCE NUMERALS

(94) 10, 10a, 10b, 10c, 10d Sputtering target 20, 20a, 20b, 20c, 20d Permanent magnet 30, 30a, 30b, 30c, 30d Yoke 40 Anode 50 Light stopping shield 60 Plasma 70, 70, 80, 80 Beam of sputtered particles 90 Horizontal shield plate 100 Vertical shield plate S, S Substrate 210 Cylindrical section 211 Flow passage 211a Linear section 211b Turn back section 220, 230 Circular board 240 Shaft 300 Film