Deposition-preventing part for physical vapor deposition apparatuses

Abstract: A deposition-preventing part, particularly a masking tool, which is used over an area to be protected from adhesion of a physical vapor deposition film, for physical vapor deposition apparatuses which are used to form physical vapor deposition films of metals, particularly noble metals, on CD-ROM, CD-R or CD-E substrates. One or more of a solder-plated Cu wire, a solder-plated Cu foil tape, an Al foil tape and a synthetic resin tape are attached, in a peelable manner, on a solder film formed on the surface of the substrate of a deposition-preventing part such as a masking tool, which has a surface roughness of 0.01 - 1 µm when expressed as the arithmetic mean roughness defined according to JIS B 0601, a thickness of 5-100 µm and a melting point of 100-450°C.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a mask (e.g., masking tool, shielding ring, shutter, etc.) which is used over an area to be protected from adhesion of a physical vapor deposition film when a physical vapor deposition apparatus is used to form a physical vapor deposition metal film, particularly a physical vapor deposition noble-metal film, as a reflective film on the surface of the substrate of a CD-ROM (read-only compact disc), CD-R (recordable and regenerable compact disc), or CD-E (erasable compact disc) (hereunder collectively referred to as CD), and further to a masking tool for physical vapor deposition apparatuses for noble metals, particularly Au. DESCRIPTION OF THE RELATED ART Preparation of CDs, such as CD-ROMS, CD-Rs and CD-Es, with physical vapor deposition Au films formed as reflective films on the substrate surfaces has been well known, and physical vapor deposition apparatuses for Au which are used for the preparation are, as illustrated in Fig. 1, each composed of a shielding ring 5 for preventing adhesion of a physical vapor deposition Au film on the inner wall of the vessel (not shown) of the physical vapor deposition apparatus for Au, a shutter 6 for temporarily stopping the flow of active Au metal 7 which is generated from the Au target when a CD prepared with a ring-shaped physical vapor deposition Au film 4 formed on the surface of the CD substrate 1 is replaced by a fresh CD substrate 1. In order to form the ring-shaped, physical vapor deposition Au film 4 on the surface of the CD substrate 1 using an apparatus of the type mentioned above for physical vapor deposition of Au, as illustrated in Fig. 1, the active Au metal 7 which has been generated from the Au target 3 is deposited by physical vapor deposition on the CD substrate 1 which has a masking tool 2 overlaid thereon and is placed in the shielding ring 5 of the physical vapor deposition apparatus for Au. The masking tool 2 which is overlaid on the CD substrate 1 can be prepared with any metallic material, but is mainly made of Cu or a Cu alloy, and as illustrated in the perspective view in Fig. 2, it comprises a disc-shaped center masking shield 21 and a ring-shaped peripheral masking shield 22, with such a configuration that the center masking shield 21 and the peripheral masking shield 22 are attached concentrically and so as to form a ring-like opening 23 between the center masking shield 21 and the peripheral masking shield 22, and the center masking shield 21 is supported, via a support 26, by a supporting arm 25 which extends from a peripheral barrel 24. When the masking tool 2 constructed in this way is overlaid on the CD substrate 1 and a ring-shaped physical vapor deposition Au film 4 is formed on the surface of the CD substrate 1, the physical vapor deposition Au film 4 naturally adheres to the surface of the overlying masking tool 2 as well. The physical vapor deposition Au film 4 which has adhered to the surface of the masking tool 2 is of course recovered, and known methods for the recovery include a) recovering by mechanical peeling such as sand blasting; b) formation of an aluminum film on the surface of the masking tool and recovering of the physical vapor deposition Au film formed on the aluminum film through dissolution of the aluminum-film film in an aqueous NaOH solution; c) use of a masking tool with an electroplating layer of a metal of the platinum group (Pt, Rh, Ir, Ru, etc.) formed on the surface and recovering of the Au which has adhered to the surface of the masking tool by physical vapor deposition, using a commercially available gold-removing agent. After the Au formed by physical vapor deposition has been recovered and removed according to any of the above-mentioned methods, the masking tool is reused. In summary, known masking tools of the prior art include masking tools consisting only of masking tool substrates made of Cu or a Cu alloy, masking tools comprising aluminum films formed on the surfaces of the masking tool substrates made of Cu or a Cu alloy, and masking tools comprising electroplating layers of a metal of the platinum group (Pt, Rh, Ir, Ru, etc.) formed on the surfaces of the masking tool substrates made of Cu or a Cu alloy. Recovering by mechanical peeling such as sand blasting, however, is not preferred as a method of recycling expensive masking tools over the long term, since masking tools, which must have high dimensional precision and high levels of surface evenness, have extremely shorter working lives due to deformation or reduction in size after repeated recycling. In addition, recovery of Au from powder resulting from processing by sand blasting can be accomplished only with poor efficiency, since many steps are required for the recovery due to inclusion of Cu or a Cu alloy in the powder deriving from the masking tools. On the other hand, the method of forming an aluminum film on the surface of the masking tool by physical vapor deposition and forming an Au film on the aluminum film by physical vapor deposition, has a drawback in that a fresh aluminum film must be formed each time the masking tool is used after recovery of the physical vapor deposition Au film, the regenerated masking tool must be stored with care since the formed aluminum film tends to change into an alumina coating, and further the Cu base can undergo corrosion due to immersion in an NaOH solution for recovery. Accordingly, the most often used method is currently the one described in c) above, where a masking tool with an electroplating layer of a metal of the platinum group formed thereon is used, and the masking tool with Au adhering thereto by physical vapor deposition is immersed in an aqueous solution of a commercially available gold-removing agent, KCN and NaOH which is kept at 50°C or lower, and the Au which has adhered by physical vapor deposition is recovered as a cyanogen complex. However, since electroplating layers of metals of the platinum group have remarkably different plating-layer thicknesses depending on the configurations of the substrates, it has been difficult to obtain uniform electroplating layers of metals of the platinum groups. For example, one problem has been that when masking tool substrates made of Cu or Cu alloys have pinholes or acute portions in the surfaces, the electroplating layers of metals of the platinum group on such portions become extremely thin, and dissolution and corrosion of the masking tool substrates made of Cu or Cu alloys start at these thin portions of the plating layers, thus reducing the number of times the masking tools can be recycled. JP-A-60 174 874 discloses a mask for preventing unwanted deposition of metal for use in a physical vapor deposition apparatus. The mask comprises a substrate supporting a low melting point In alloy such as an In-48% Sn alloy having a melting point of 117°C. JP-A-04297098 discloses a metal foil tape plated with nickel which may be vapor-deposited on one side with aluminum. The reverse side may then be coated with solder. SUMMARY OF THE INVENTION In view of the prior art described above, the present inventors have researched in order to provide a masking tool from which the physical vapor deposition Au film is more easily recovered than the masking tools of the prior art and which can be recycled many times, with the following findings: (a) Formation of a solder film on the surface of a masking tool substrate made of Cu or a Cu alloy allows shorter, easier peeling of a possible vapor deposition Au film on the surface of the solder film as a result of shorter, easier removal of the solder film on the surface of the masking tool substrate by immersion of the masking tool with the physical vapor deposition Au film adhering thereto, in a solution of a solder-removing agent, while shaking if necessary; (b) Here, use of a solder-removing agent which results in less corrosion of Cu and Cu alloys naturally results in less corrosion of the masking tool substrate, and thus the masking tool can be recycled more times than according to conventional methods of recovering the physical vapor deposition Au deposited on the masking tool; (c) The solder film can be more easily formed than aluminum films and films of metals of the platinum group of the prior art; and (d) When physical vapor deposition of Au is continued for a long time using the above-mentioned masking tool with a solder film formed thereon, the Au sometimes covers the entire surface of the solder film of the masking tool to prevent the solder-removing agent from coming into contact with the solder film, and this results in failure to peel the solder film from the masking tool and thus to recover the noble metal even when the Au-adhering masking tool is immersed in a solution of a solder-removing agent and shaken. Even in such a case, however, when a solder-plated Cu wire or Cu foil tape, an Al foil tape or a synthetic resin tape is attached in a peelable manner, via an adhesive, on the top surface of the solder film formed on the surface of the masking tool substrate made of Cu or a Cu alloy, and the solder-plated Cu wire or Cu foil tape, the A1 foil tape or the synthetic resin tape is peeled off after physical vapor deposition of Au, the portion of the solder film on the surface of the masking tool substrate which is in contact with the applied Cu wire, Cu foil tape, A1 foil tape or synthetic resin tape, is exposed. Accordingly, when the masking tool with Au adhering thereto by physical vapor deposition, which is provided with the partially exposed solder film, is then immersed in a solution of a solder-removing agent, while shaking if necessary, peeling of the solder film starts at the exposed portion of the solder film, and this results in removal of the solder film on the entire masking tool and eventual shorter, easier peeling of the physical vapor deposition Au film formed on the surface of the solder film. Accordingly the present invention provides a mask for preventing unwanted deposition of metal on a surface for use in a physical vapour deposition apparatus, the mask comprising a substrate having a solder film formed on a surface thereof; characterised in that the solder film has a thickness of 5-100 µm and a surface roughness of 0.01-1 µm in terms of the arithmetic mean roughness defined according to JIS B 0601, and in that a wire or tape is releasably attached to the solder film by an adhesive in such a way that the wire or tape may be peeled away to expose the portion of the solder film where it was releasably attached, the wire or tape being: (i) a solder-plated metal wire or a solder-plated metal foil tape, (ii) an Al foil tape, (iii) a solder-plated metal wire or a solder-plated metal foil tape releasably attached to the solder film using an Al foil tape with the adhesive applied to one side thereof, (iv) a synthetic resin tape, or (v) a solder-plated metal wire or a solder-plated metal foil releasably attached to the solder film using a synthetic resin tape with the adhesive applied to one side thereof. It is preferred that the solder film is formed from soft solder having a melting point of 100-450°C. It is further preferred that the surface of the substrate is composed of copper or a copper alloy. The nature of the copper alloy is not particularly limited, and any copper alloy may be used so long as it performs the intended function. Examples of metals which can be alloyed with copper include one or more of zinc, tin, aluminum, nickel, zirconium and chromium. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view illustrative of the configuration of a physical vapor deposition apparatus for Au; Fig. 2 is a perspective view of a masking tool; Fig. 3 is a plan view of a masking tool; Fig. 4 is a plan view of a masking tool; Fig. 5 is a plan view of a masking tool; and Fig. 6 is a plan view of a masking tool. DETAILED DESCRIPTION OF THE INVENTION The mask of the present invention is more fully described as follows. The solder film mentioned above which is formed on a masking tool substrate, particularly a masking tool substrate made of Cu or a Cu alloy, cannot fully protect the surface of the masking tool substrate when the film thickness is less than 5 µm, whereas the solder film disadvantageously requires too much time for removal when the film thickness exceeds 100 µm. Accordingly, the film thickness of the solder film formed on the substrate of a masking tool is 5-100 µm. A more preferred range of the film thickness of the solder film is 10-50 µm. Although the solder of the solder film mentioned above can be any solder which meets the requirements specified by JIS Z 3282-86, use of solder having a melting point of 100°C or more, more specifically soft solder having a melting point of 100-450°C, is preferred in view of the heat resistance of the solder film which is required during physical vapor deposition of Au and also in order to prevent production of an intermetallic compound between Cu in the masking tool substrate and Sn which is contained in the solder. The solder film according to the present invention can also be formed on the surface of a masking tool which is used for physical vapor deposition apparatuses for noble metals (Ag, Pt, Pd and Rh) other than Au, and can further be formed on the surface of, for example, the shielding ring 5 or the shutter 6 illustrated in Fig. 1, for physical vapor deposition apparatuses, to increase the number of times of recycling these various parts, without being limited to masking tools for physical vapor deposition apparatuses. Although the mask substrate made of a metal can be prepared of any metallic material so long as the material has excellent heat resistance, the material preferably is Cu or a Cu alloy in view of the heat conductivity and the price, and the solder film on the surface of the deposition-preventing part substrate can be formed by electroplating, electroless plating, physical vapor deposition, application of solder paste or any other process. All that is needed to remove the metal film adhering to the surface of the mask provided with the solder film according to the present invention is to immerse the deposition-preventing part with the metallic film adhering thereto in a solution of a solder-removing agent, while shaking if necessary. The mask provided by the present invention can be used as not only a mask for physical vapor deposition apparatuses for noble metals (Au, Ag, Pt, Pd and Rh), but also as a mask for physical vapor deposition apparatuses for metals other than noble metals, such as Cr, Ni, Al and Cu. The mask provided by the present invention has a wire or tape releasably attached to the solder film by an adhesive. If such a wire or tape is not present, when the noble metal covers the entire surface of the solder film of the mask, the solder-removing agent cannot come into contact with the solder film. This makes it difficult to peel the solder film from the mask and thus requires much time for the recovery of the noble metal even when the noble metal-adhering mask is immersed in a solution of a solder-removing agent and shaken. To solve this problem, the wire or tape is releasably attached to the solder film by an adhesive in such a way that the wire or tape may be peeled away to expose the portion of the solder film where it was releasably attached. The wire or tape is one of: (i) a solder-plated metal wire or a solder-plated metal foil tape, (ii) an Al foil tape, (iii) a solder-plated metal wire or a solder-plated metal foil tape releasably attached to the solder film using an Al foil tape with the adhesive applied to one side thereof, (iv) a synthetic resin tape, or (v) a solder-plated metal wire or a solder-plated metal foil releasably attached to the solder film using a synthetic resin tape with the adhesive applied to one side thereof. After deposition of Au over the mask, the wire or tape is peeled away to expose the portion of the solder film where it was releasably attached. Accordingly, when the mask with Au adhering thereto by physical vapor deposition, which is provided with the partially exposed solder film, is then immersed in a solution of a solder-removing agent, while shaking if necessary, the physical vapor deposition Au film formed on the surface of the solder film is more easily peeled in a short time at the same time when the solder film is removed. The solder film for use in the present invention can be formed on not only the surfaces of the above-described masking tools for physical vapor deposition apparatuses for Au, but also on the surfaces of various masks, such as shielding rings or shutters, for physical vapor deposition apparatuses for noble metals (Ag, Pt, Pd and Rh) other than Au, to increase the number of times these various parts can be recycled. The mask provided with the solder film according to the present invention can be used as not only a deposition-preventing part for physical vapor deposition apparatuses for noble metals (Au, Ag, Pt, Pd and Rh), but also as a mask for physical vapor deposition apparatuses for metals other than noble metals, such as Cr, Ni, Al and Cu. In cases where the surface of the solder film formed on the mask substrate made of a metal is too smooth as defined by a measurement smaller than 0.01 µm in terms of the arithmetic mean roughness defined by JIS B 0601 (hereunder referred to as "Ra"), the metal deposited on the mask by vapor deposition peels off to cause formation of particles during the process of vapor deposition, whereas the surface of the solder film formed on the mask substrate made of a metal is too rough as defined by a measurement greater than 1 µm when expressed as Ra, the adhesive used to attach the metal tape to the surface of the solder film remains in hollows of the solder film when it is attempted to peel the metal tape from the solder film, and eventually the remaining adhesive disadvantageously prevents chemical dissolution of the solder film when the deposition-preventing part is immersed in a solution of a solder-removing agent after physical vapor deposition. Therefore, the surface roughness of the solder film formed on the mask substrate made of a metal is within the range of 0.01 - 1 µm, preferably 0.1 - 0.8 µm, when expressed as Ra. EXAMPLES Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified. Reference Example 1 A lathed (3.2-S) masking tool substrate made of Cu was prepared for the preparation of CD-ROMS. The surface roughness of the masking tool substrate made of Cu for preparing CD-ROMs was measured to be 0.58 µm when expressed as Ra. In addition, there was also prepared a plating solution composed of: 57 g/l of lead methanesulfonate; 3 g/l of tin methanesulfonate; 0.72 N free methanesulfonic acid; and 33 g/l of a commercially available lubricating agent. The plating solution was used to prepare Masking tool 1 by forming a film of Pb-5% Sn solder (m. p.: 310°C) having a thickness of 10 µm and a surface roughness Ra of 0.75 µm, on the surface of the masking tool substrate made of Cu, under the following conditions: temperature of the plating solution: 20°C, stirring condition: 1,000 r.p.m. (by a magnetic stirrer), cathodic current-density: 5 A/dm 2 , and plating time: 5 minutes. Reference Example 2 The masking tool substrate made of Cu for the preparation of CD-ROMs which was prepared in Reference Example 1 was immersed in a plating solution composed of: 14.8 g/l of lead methanesulfonate; 25.2 g/l of tin methanesulfonate; 0.72 N free methanesulfonic acid; and 33 g/l of a commercially available lubricating agent, and Masking tool 2 was prepared by forming a film of Pb-63% Sn solder (m. p.: 183°C) having a thickness of 20 µm and a surface roughness Ra of 0.75 µm, on the surface of the masking tool substrate made of Cu, under the following conditions: temperature of the plating solution: 20°C; stirring condition: 1,000 r.p.m. (by a magnetic stirrer); cathodic current-density: 5 A/dm 2 ; and plating time: 10 minutes. Reference Example 3 The masking tool substrate made of Cu for the preparation of CD-ROMs which was prepared in Reference Example 1 was subjected to abrasive processing with abrasive paper (#1,500) to prepare a masking tool substrate having a surface roughness Ra of 0.07 µm. A 50-µm-thick film of Pb5% In-5% Ag solder (m. p. : 290°C) was formed on the surface of the masking tool substrate by vapor deposition under the conventional conditions to prepare Masking tool 3. The surface roughness Ra of the solder film of Masking tool 3 was 0.12 µm. Reference Example 4 The masking tool substrate made of Cu for the preparation of CD-ROMs which was subjected to abrasive processing with abrasive paper (#1,500) in Reference Example 3, was further subjected to buffing with 1-µm- diamond abrasive grains to prepare a masking tool substrate having a surface roughness Ra of 0.02 µm. A 90-µm-thick film of Sn-5% Ag solder (m. p.: 221°C) was formed on the surface of the masking tool substrate by vapor deposition under the conventional conditions to prepare Masking tool 4. The surface roughness Ra of the solder film of Masking tool 4 was 0.10 µm. Reference Example 5 The masking tool substrate made of Cu for the preparation of CD-ROMs which was prepared in Reference Example 3 and has a surface roughness Ra of 0.07 µm, was immersed in a plating solution composed of: 60 g/l of lead methanesulfonate; 0.72 N free methanesulfonic acid; and 33 g/l of a commercially available lubricating agent, and Masking tool 5 was prepared by forming a film of pure Pb solder (m. p.: 328°C) having a thickness of 100 µm and a surface roughness Ra of 0.45 µm, on the surface of the masking tool substrate made of Cu, under the following conditions: temperature of the plating solution: 20°C; stirring condition: 1,000 r.p.m. (by a magnetic stirrer); cathodic current-density: 5 A/dm 2 ; and plating time: 50 minutes. Reference Example 6 The masking tool substrate made of Cu for the preparation of CD-ROMs which was prepared in Reference Example 3 and has a surface roughness Ra of 0.07 µm, was immersed in a plating solution composed of: 60 g/l of tin methanesulfonate; 0.72 N free methanesulfonic acid; and 33 g/l of a commercially available lubricating agent, and Masking tool 6 was prepared by forming a film of pure Sn solder (m. p.: 232°C) having a thickness of 5 µm and a surface roughness Ra of 0.25 µm, on the surface of the masking tool substrate made of Cu, under the following conditions: temperature of the plating solution: 20°C; stirring condition: 1,000 r.p.m. (by a magnetic stirrer); cathodic current-density: 5 A/dm 2 ; and plating time: 2.5 minutes. Example 1 As illustrated in the plan view in Fig. 3, a Cu wire 27 having a 10-µm-thick film plated with Pb-5% Sn solder (m. p.: 310°C), was bonded to a supporting arm 25 with a trace quantity of a synthetic rubber-based-adhesive in a peelable manner, on the surface of Masking tool 1 which was prepared in Reference Example 1 by forming a film of Pb-5% Sn solder (m. p.: 310°C) having a thickness of 10 µm and a surface roughness Ra of 0.75 µm, on the surface of a masking tool substrate made of Cu, to prepare Masking tool 7 according to the present invention. Masking tool 7 according to the present invention was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 7 according to the present invention, the solder-plated Cu wire 27 which was bonded onto the solder film of the masking tool was removed to partially expose the solder film formed on the surface of the masking tool substrate, and the masking tool was immersed in a 5 liters of a solder-removing solution, (a 50% by volume solution of lactic acid in water) (solution temperature: 40°C) under application of ultrasonic vibration. As a result, the solder film on the surface of the masking tool substrate dissolved in the solder-removing solution, the adhering physical vapor deposition Au film completely peeled off in the solder-removing solution in 17 minutes, and the physical vapor deposition Au film which peeled off into the solder-removing solution was easily recovered by filtering off the solder-removing solution. The foregoing operation for recovery of the Au and regeneration of the masking tool substrate was repeated, and the number of recycling times of Masking tool 7 according to the present invention was counted to be 105. Example 2 As illustrated in the plan view in Fig. 4, a Cu wire 27 having a 10-µm-thick film plated with Pb-5% Sn solder (m. p.: 183°C), was bonded and fixed, in a peelable manner, to a supporting arm 25 using an Al foil tape 28 with an adhesive applied to the underside thereof, on the surface of Masking tool 2 which was prepared in Reference Example 2 by forming a film of Pb-63% Sn solder (m.p.: 183°C) having a thickness of 20 µm and a surface roughness Ra of 0.75 µm, on the surface of a masking tool substrate made of Cu, to prepare Masking tool 8 according to the present invention. Masking tool 8 according to the present invention was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 8 according to the present invention, the solder-plated Cu wire 27 which was bonded and fixed onto the solder film of the masking tool and the Al foil tape 28 were removed to partially expose the solder film formed on the surface of the masking tool substrate, and the masking tool was immersed in a 5 liters of a solder-removing solution (a 50% by volume solution of acetic acid in water) (solution temperature: 40°C) under application of ultrasonic vibration. As a result, the solder film on the surface of the masking tool substrate dissolved in the solder-removing solution, the adhering physical vapor deposition Au film completely peeled off in the solder-removing solution in 14 minutes, and the physical vapor deposition Au film which peeled off into the solder-removing solution was easily recovered by filtering off the solder-removing solution. The foregoing operation for recovery of the Au and regeneration of the masking tool substrate was repeated, and the number of recycling times of Masking tool 8 according to the present invention was counted to be 72. Example 3 As illustrated in the plan view in Fig. 5, an Al foil tape 28 with an adhesive applied to the underside thereof was bonded, in a peelable manner, to the surface of Masking tool 3 which was prepared in Reference Example 3 by forming a film of Pb-5% In-5% Ag solder (m. P. : 290°C) having a thickness of 50 µm and a surface roughness Ra of 0.12 µm, on the surface of a masking tool substrate made of Cu by vapor deposition under the conventional conditions, to prepare Masking tool 9 according to the present invention. Masking tool 9 according to the present invention was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 9 according to the present invention, the Al foil tape 28 which was bonded onto the solder film of the masking tool was removed to partially expose the solder film formed on the surface of the masking tool substrate, and the masking tool was immersed in a 5 liters of a solder-removing solution (a 50% by volume solution of acetic acid in water) (solution temperature: 40°C) under application of ultrasonic vibration. As a result, the solder film on the surface of the masking tool substrate dissolved in the solder-removing solution, the adhering physical vapor deposition Au film completely peeled off in the solder-removing solution in 7 minutes, and the physical vapor deposition Au film which peeled off into the solder-removing solution was easily recovered by filtering off the solder-removing solution. The foregoing operation for recovery of the Au and regeneration of the masking tool substrate was repeated, and the number of recycling times of Masking tool 9 according to the present invention was counted to be 85. Example 4 As illustrated in the plan view of the masking tool in Fig. 6, a vinyl tape 29 with an adhesive applied to the underside thereof was bonded, in a peelable manner, onto the solder film of a peripheral masking shield 22 of Masking tool 4 which was prepared in Reference Example 4 by forming a vapor deposition film of Sn-5% Ag solder (m. p.: 221°C) having a thickness of 90 µm and a surface roughness Ra of 0.10 µm, on the surface of a masking tool substrate made of Cu, to prepare Masking tool 10 according to the present invention. Masking tool 10 according to the present invention was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 10 according to the present invention, the vinyl tape 29 which was bonded onto the solder film of the masking tool was removed to partially expose the solder film formed on the surface of the masking tool substrate, and the masking tool was immersed in a 5 liters of a solder-removing solution (a 50% by volume solution of acetic acid in water) (solution temperature: 40°C) under application of ultrasonic vibration. As a result, the solder film on the surface of the masking tool substrate dissolved in the solder-removing solution, the adhering physical vapor deposition Au film completely peeled off in the solder-removing solution in 5 minutes, and the physical vapor deposition Au film which peeled off into the solder-removing solution was easily recovered by filtering off the solder-removing solution. The foregoing operation for recovery of the Au and regeneration of the masking tool substrate was repeated, and the number of recycling times of Masking tool 10 according to the present invention was counted to be 63. Example 5 By using a vinyl tape with an adhesive applied to the underside thereof, a Cu foil tape with a 10-µm-thick, pure Pb-plated film formed thereon was bonded, in a peelable manner, onto the solder film of the supporting arm of the masking tool 5 which was prepared in Reference Example 5 by forming a film of pure Pb solder (m. p.: 328°C) having a thickness of 100 µm and a surface roughness Ra of 0.45 µm, on the surface of a masking tool substrate made of Cu, to prepare Masking tool 11 according to the present invention. Masking tool 11 according to the present invention was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM record medium. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 11 according to the present invention, the Cu foil tape and the vinyl tape which were bonded onto the solder film of the masking tool were removed to partially expose the solder film formed on the surface of the masking tool substrate, and the masking tool was immersed in a 5 liters of a solder-removing solution (a 50% by volume solution of acetic acid in water) (solution temperature: 40°C) under application of ultrasonic vibration. As a result, the solder film on the surface of the masking tool substrate dissolved in the solder-removing solution, the adhering physical vapor deposition Au film completely peeled off in the solder-removing solution in 20 minutes, and the physical vapor deposition Au film which peeled off into the solder-removing solution was easily recovered by filtering off the solder-removing solution. The foregoing operation for recovery of the Au and regeneration of the masking tool substrate was repeated, and the number of recycling times of the masking tool was counted to be 82. Example 6 An Al foil tape and a vinyl tape each with an adhesive applied to the underside thereof were bonded, in a peelable manner, onto the solder film of each of the supporting arm and the center masking shield of the solder film-coated masking tool 6 which was prepared in Reference Example 6 by forming a film of pure Sn solder (m. p.: 232°C) having a thickness of 5 µm and a surface roughness Ra of 0.25 µm, on the surface of a masking tool substrate made of Cu, to prepare Masking tool 12 according to the present invention. Masking tool 12 according to the present invention was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of masking tool 12 according to the present invention, the Al foil tape and the vinyl tape which were bonded onto the solder film of Masking tool 12 according to the present invention were removed to partially expose the solder film formed on the surface of the masking tool substrate, and the masking tool was immersed in 5 liters of a solder-removing solution (a 50% by volume solution of acetic acid in water) (solution temperature: 40°C) under application of ultrasonic vibration. As a result, the solder film on the surface of the masking tool substrate dissolved in the solder-removing solution, the adhering physical vapor deposition Au film peeled off in the solder-removing solution in 14 minutes, and the physical vapor deposition Au film which peeled off into the solder-removing solution was easily recovered by filtering off the solder-removing solution. The foregoing operation for recovery of the Au and regeneration of the masking tool substrate was repeated, and the number of recycling times of the masking tool was counted to be 85. Comparative Example 1 A 1-µm-thick Rh film was formed, under conventional electroplating conditions, on the surface of the masking tool substrate made of Cu for the preparation of CD-ROMs which was prepared in Reference Example 1, to prepare Masking tool 1 according to the prior art. Masking tool 1 according to the prior art was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 1 according to the prior art, the masking tool was immersed in a gold-removing solution with a commercially available gold-removing agent dissolved therein (solution temperature: 30°C) for 5 hours to recover the Au. The recovery of the Au and regeneration of the masking tool was repeated, and the number of recycling times of Masking tool 1 according to the prior art was counted to be 8. Comparative Example 2 A 0.5-µm-thick Pt film was formed, under conventional electroplating conditions, on the surface of the masking tool substrate made of Cu for the preparation of CD-ROMs which was prepared in Reference Example 1, to prepare Masking tool 2 according to the prior art. Masking tool 2 according to the prior art was used in order to form a physical vapor deposition Au film on the surface of a CD-ROM substrate to thereby prepare a CD-ROM. Upon adhesion of a 1-mm-thick physical vapor deposition Au film onto the surface of Masking tool 2 according to the prior art, the masking tool was immersed in a gold-removing solution with a commercially available gold-removing agent dissolved therein (solution temperature: 30°C) for 5 hours to recover the Au. The recovery of the Au and regeneration of the masking tool was repeated, and the number of recycling times of Masking tool 2 according to the prior art was counted to be 9. The results of Examples 1-6 and Comparative Examples 1-2 show that: (a) Masking tools 1-6 according to the present invention which have solder films formed thereon all have greatly increased numbers of recycling times as compared with Masking tools 1-2 according to the prior art which have films of platinum-group metals formed thereon; and (b) Although 5 hours are required for removal of a 1-mm-thick physical vapor deposition Au film in the case of Masking tools according to the prior art which have films of platinum-group metals formed thereon, the peeling can be completed in a shorter time than 60 minutes for Masking tools 1-6 according to the present invention, and this short time required for the peeling apparently increased the efficiency. Although the foregoing description is focused on comparison in peeling of physical vapor deposition Au films adhering to masking tools for physical vapor deposition apparatuses from the masking tools between Examples and Comparative Examples, the present invention is not limited to deposition-preventing parts for physical vapor deposition apparatuses for Au, and can also be applied to deposition-preventing parts for physical vapor deposition apparatuses for noble metals (Ag, Pt, Pd and Rh) other than Au, and further such metals as Cr, Ni, Al and Cu. As described above, the deposition-preventing parts according to the present invention for physical vapor deposition apparatuses which have solder films formed thereon, particularly the masking tools, have greatly increased numbers of recycling times, and allow removal of the adhering physical vapor deposition films in a short time, and this greatly contributes to lower costs. LIST OF REFERENCE CHARACTERS 1 CD-ROM, CD-R or CD-E SUBSTRATE 2 MASKING TOOL 3 Au TARGET 4 PHYSICAL VAPOR DEPOSITION Au FILM 5 SHIELDING RING 6 SHUTTER 7 ACTIVE Au METAL 21 CENTER MASKING SHIELD 22 PERIPHERAL MASKING SHIELD 23 RING-LIKE OPENING 24 PERIPHERAL BARREL 25 SUPPORTING ARM 26 SUPPORT 27 SOLDER-PLATED Cu WIRE 28 Al FOIL TAPE 29 VINYL TAPE 30 SOLDER FILM-COATED MASKING TOOL

Claims: A mask for preventing unwanted deposition of metal on a surface for use in a physical vapour deposition apparatus, the mask comprising a substrate having a solder film formed on a surface thereof; characterised in that the solder film has a thickness of 5-100 µm and a surface roughness of 0.01-1 µm in terms of the arithmetic mean roughness defined according to JIS B 0601, and in that a wire or tape is releasably attached to the solder film by an adhesive in such a way that the wire or tape may be peeled away to expose the portion of the solder film where it was releasably attached, the wire or tape being: (i) a solder-plated metal wire or a solder-plated metal foil tape, (ii) an Al foil tape, (iii) a solder-plated metal wire or a solder-plated metal foil tape releasably attached to the solder film using an Al foil tape with the adhesive applied to one side thereof, (iv) a synthetic resin tape, or (v) a solder-plated metal wire or a solder-plated metal foil releasably attached to the solder film using a synthetic resin tape with the adhesive, applied to one side thereof. A mask according to Claim 1, wherein the solder film is formed from soft solder having a melting point of 100 to 450°C. A mask according to Claim 1 or Claim 2, wherein said surface of said substrate is composed of copper or a copper alloy. A mask according to any preceding Claim, which is in the form of a masking tool, shielding ring or a shutter.

Inventors: HASHIMOTO YORISHIGE, KINOSHITA MAKOTO, MASHIMA MUNENORI, UCHIYAMA NAOKI, HASHIMOTO, YORISHIGE, KINOSHITA, MAKOTO, MASHIMA, MUNENORI, UCHIYAMA, NAOKI, Hashimoto, Yorishige, c/o Sanda Plant, Kinoshita, Makoto, c/o Sanda Plant, Mashima, Munenori, c/o Sanda Plant, Uchiyama, Naoki, c/o Sanda Plant
Applicants: MITSUBISHI MATERIALS CORP, MITSUBISHI MATERIALS CORPORATION
Application year: 1997
Main classification: C23C14
IPC codes: G11B5, C23C14, C23C30, G11B7