JP2009249703A - Method for producing metal thin film-laminated board and vacuum film deposition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for producing a board obtained by laminating metal films on both the sides of a long-length resin film which is produced through a process by vacuum film deposition, in which the narrow pitch wiring of a both side flexible wiring board is possible. <P>SOLUTION: In the method for producing a board where metal thin films are vacuum-deposited on both the sides of a long-length film, so as to laminate the metal thin films on both the sides of the long-length film, after the metal thin films are vacuum-deposited on both the sides of the long-length resin film, an organic matter liquid film is formed on the surface of at least one metal thin film of the metal thin films, and the metal thin film-laminated layer board is coiled. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a film forming method for forming a metal thin film on both sides of a long film and a film forming apparatus for performing the film forming method.

  A long resin film has flexibility and can be easily processed. Therefore, a metal film or an oxide film is formed on the surface of the long resin film, and it is widely used in the industry as an electronic component, an optical component, a packaging material, and the like. For example, a driver circuit of a liquid crystal display employs COF (Chip on Film) having characteristics corresponding to flexibility and fine wiring. In addition, flexible wiring boards are used in small electronic devices such as mobile phones. Due to the recent increase in mounting density of electronic components of electronic devices, flexible wiring boards and the like have become double-sided flexible wiring boards or multilayer boards.

  By the way, the substrate for COF and the flexible wiring substrate are manufactured by processing a substrate in which a metal film is laminated on a polyimide film by a subtractive method or the like. In order to manufacture a substrate in which a metal film is laminated on a polyimide film, a method of electroplating copper on the copper thin film through a step of vacuum-depositing a metal thin film such as a nickel-chromium alloy and copper on the polyimide film, copper A method of overheating and pressing a foil and a polyimide film is known. Among them, a substrate that has undergone a step of vacuum-depositing a metal thin film on a polyimide film can accommodate narrow pitch wiring of less than 50 μm because the polyimide film and the metal thin film layer are continuous.

To manufacture a substrate with a metal film laminated on both sides of a polyimide film, when the film is formed by a vacuum film formation method, the film is formed on both sides of the polyimide film and wound, and then between the front and back sides of the metal thin film laminate substrate The metal surfaces come into contact with each other and are pressed by the tension at the time of winding, and the metal surfaces are bonded to each other under a reduced pressure of 10 ⁻¹ Pa. When it is unwound in the next step, since the adhesion between the metals is strong, a phenomenon that the metal thin film is peeled off from the polyimide occurs, resulting in a fatal defect such as a pinhole.

  In addition, as another method for preventing the surfaces of the metal thin films between the front and back surfaces of the metal thin film multilayer substrate S from being bonded in a vacuum, there is a method of winding while laminating the long resin film and the metal thin film multilayer substrate. . However, since a long film laminating mechanism is added to the vacuum film forming apparatus, the apparatus becomes complicated and management becomes complicated.

  If the board | substrate which laminated | stacked the metal film on both surfaces of the polyimide film by the method of carrying out the thermocompression bonding of copper foil and a polyimide film is manufactured for the operation under atmospheric pressure, the metal surfaces between the above-mentioned front and back both surfaces will not couple | bond together. Japanese Patent No. 3675805 discloses a method for producing a substrate in which a copper film is superheat-adhered to a polyimide film having a copper foil layer on one side and a metal film is laminated on both sides.

However, in the method disclosed in Japanese Patent No. 3675805, the surface of the copper foil in contact with the polyimide is roughened in order to increase the adhesion between copper and polyimide. When wiring is processed by etching, the wiring processing pitch is limited due to the unevenness of the roughened surface, and it is not possible to handle narrow pitch wiring of less than 50 μm.
Japanese Patent No. 3675805

  An object of the present invention is to provide a manufacturing method and a manufacturing apparatus of a metal thin film laminated substrate in which metal films are laminated on both sides of a long resin film capable of narrow pitch wiring of a double-sided flexible wiring substrate.

The first invention of the present invention is a method for producing a metal thin film laminate substrate in which a metal thin film is vacuum-deposited on both sides of a long resin film,
After a metal thin film is vacuum-deposited on both sides of the long resin film, an organic liquid film is applied and formed on the surface of at least one of the metal thin films using an organic liquid coating mechanism, and then the long resin film It is an invention of a method for manufacturing a metal thin film multilayer substrate, wherein the metal thin film multilayer substrate in which the metal thin films are laminated on both sides is wound up.

  The second invention is the method for producing a metal thin film multilayer substrate according to the first invention, wherein the organic liquid film is applied by a porous roll or a doctor blade.

  The third invention is characterized in that the vapor pressure of the organic liquid is 1/100 or less of the pressure of the atmosphere during film formation of the vacuum film forming apparatus. It is a manufacturing method of a laminated substrate.

  A fourth invention of the present invention is a vacuum film forming apparatus provided with a vacuum film forming mechanism facing a take-up roll, a can roll, a take-up roll and a can roll of a long resin film. An organic liquid application mechanism for forming an organic liquid film by applying an organic liquid film on at least one surface of the long resin film between the can roll and the take-up roll on the path is provided. This is an invention of a vacuum film forming apparatus.

  According to a fifth aspect of the present invention, there is provided the vacuum film forming apparatus according to the fourth aspect, wherein the organic liquid film is applied by a porous roll in the organic liquid application mechanism.

  According to a sixth aspect of the present invention, there is provided the vacuum film forming apparatus according to the fourth aspect, wherein the organic liquid film is applied by a doctor blade in the organic liquid application mechanism.

  The seventh organic liquid application mechanism of the present invention includes a container filled with an organic liquid, a guide roll for allowing the metal thin film laminated substrate to pass through the container, and outside the container and passing through the container. It is an invention of a vacuum film-forming apparatus according to a fourth invention, characterized in that it is composed of two opposing nip rolls sandwiching a subsequent metal thin film laminated substrate.

  According to the present invention, when a metal thin film is formed on both sides of a long resin film by a vacuum film forming method, it is possible to prevent bonding between the metal thin films formed on the front and back of the long resin film by winding, Next, it is possible to reduce the problem that film peeling occurs when unwinding, and it becomes possible to manufacture a metal thin film multilayer substrate corresponding to narrow pitch wiring processing.

The metal thin film multilayer substrate of the present invention is formed by, for example, forming a nickel-chromium alloy thin film layer on a polyimide film and vacuum forming a copper thin film layer on the alloy thin film layer. It is manufactured by a method of forming a copper film by plating. Here, after the said nickel-chromium alloy thin film layer and the copper thin film layer were sequentially formed and laminated | stacked on both surfaces of this polyimide film with the vacuum film-forming method, the obtained metal thin film laminated substrate was 10 ^<-1 > Pa. Winding is performed under reduced pressure. In this case, as described above, the surfaces of the metal thin films formed on both surfaces of the film are wound in contact with each other, and the surfaces of the metal thin films are wound together. The phenomenon that the metal thin film is peeled off from the polyimide at the time of bonding and unwinding may occur, resulting in a fatal defect.

  Therefore, in the method for manufacturing a metal thin film multilayer substrate of the present invention, in order to prevent such defects, a metal thin film is vacuum-deposited on one surface of the long resin film, and further a metal thin film is vacuum-deposited on the other surface. After film formation, before winding up the long metal thin film laminated substrate, an organic liquid film is formed on at least one surface of the metal thin film, and the metal thin film surfaces between the front and back surfaces of the long resin film are bonded to each other. It prevents.

  A method of manufacturing the metal thin film seat layer substrate of the present invention will be described using the vacuum film forming apparatus 10 of the present invention shown in FIG. FIG. 1 is a side view schematically showing an example of the vacuum film forming apparatus 10 of the present invention. FIG. 2 is a side view schematically showing another example of the vacuum film forming apparatus of the present invention. FIG. 3 is a side view and a front view showing an example of the organic liquid application mechanism. 4, 5 and 6 are side views schematically showing the organic liquid application mechanism. Various rolls are drawn in a circular shape, but are actually cylindrical.

The vacuum film forming apparatus 10 includes a rectangular parallelepiped housing 12 in which most of the components are stored. The casing may be cylindrical and the shape is not limited as long as the decompressed state can be maintained in the range of 10 ⁻⁴ Pa to 1 Pa. The casing has a film winding roll 13, a can roll 14, sputtering cathodes 15a and 15b, tension rolls 16a and 16b, a winding roll 17, and a porous roll 18 which is one of organic liquid application mechanisms.

  The sputtering cathodes 15a and 15b are of a magnetron cathode type and are arranged to face the can roll 14. The dimension in the width direction of the long resin film of the sputtering cathodes 15a and 15b may be wider than the width of the long resin film. For example, if it is a 500 mm long resin film, the width direction dimension of the long resin film of a sputtering cathode should just be 600 mm.

  If the diameter of the can roll 14 is 400Φ or more, a plurality of sputtering cathodes can be opposed to each other. A coolant such as water or an organic solvent circulates inside the can roll 14 to cool the long resin film during sputtering. The surface of the can roll 14 is plated with hard chrome. FIG. 2 shows a vacuum film forming apparatus 11 having two sets of can rolls and the like, and film formation can be performed on both sides of a long resin film by operating one apparatus once.

  In the vacuum film forming apparatus 10, the long resin film F is unwound from the unwinding roll 13, conveyed through the tension roll 16 a, the can roll 14, and the tension roll 16 b so as not to be loosened, and taken up by the take-up roll 17. The long resin film F is in contact with the surface of the can roll 14 and is conveyed along the surface of the can roll 14. The long resin film F is a metal thin film laminated substrate S (hereinafter referred to as a metal thin film laminated substrate S) in which metal thin films are formed on both sides and metal thin films are laminated on both sides of the long resin film. Since the vacuum film forming apparatus 10 includes a pair of can rolls and a sputtering cathode, in order to form a film on both sides of the long resin film, a substrate having a metal film laminated on one side of the long resin film is taken out, The surface of the substrate that is not formed may be formed. In the first film formation, the organic liquid film is not formed.

In the vacuum film forming apparatuses 10 and 11, sputtering is used as a film forming mechanism. When the film is formed by sputtering, the inside of the vacuum film forming apparatus is depressurized to the higher one by the vapor pressure of the organic liquid or the pressure in the range from 10 ⁻⁴ Pa to 10 ⁻³ Pa. This reduced pressure is called ultimate pressure. After the pressure is reduced to the ultimate pressure, sputtering gas (argon) is introduced, and sputtering is performed at a pressure in the range of 10 ⁻¹ Pa to about 1 Pa. Note that the film formation mechanism is not limited to sputtering, and a known vacuum film formation method such as vapor deposition can be used.

  FIG. 3 is a diagram schematically showing an example of the organic liquid application mechanism. Application of the organic liquid to the metal thin film laminated substrate S is performed with a porous roll 18 formed of a sponge. In the vacuum film forming apparatuses 10 and 11, the porous roll sandwiches the metal thin film multilayer substrate S between the porous roll and the tension roll, and rotates when the metal thin film multilayer substrate S is conveyed. Further, the rotating shaft of the porous roll is movable, and the contact pressure with the substrate having metal films laminated on both sides of the long resin film can be controlled from the outside.

  The porous roll 18 includes a cylindrical sponge 18a formed of urethane sponge, rubber sponge, or the like, and a cylindrical tube 18b inserted into a hollow portion of the cylinder. A large number of holes (not shown) are formed on the outer peripheral surface of the cylindrical tube 18b. Both end portions of the cylindrical tube 18b are rotatably fixed to the wall 12a of the housing 12 via bearings (rotary joints) 36 (FIG. 3B shows only one end portion of the cylindrical tube 32b. The end portion has the same configuration), and this one end portion is connected to the liquid supply pump 34 by a pipe (oil feed pipe) 38. The liquid supply pump 34 is connected to a liquid tank 39 in which the liquid L is stored.

  By operating the liquid supply pump 34, the liquid L in the liquid tank 39 is supplied to the cylindrical tube 18b through the pipe 38, and oozes out into the sponge 18a through the numerous holes of the cylindrical tube 18b. 18a contains a large amount of liquid L. The liquid L contained in the sponge 18a. It is applied to one surface of the metal thin film multilayer substrate S.

  FIG. 4 is a side view schematically showing an example of the organic liquid supply mechanism. An organic liquid is applied to the metal thin film laminated substrate S by the doctor blade 41. The organic liquid supply mechanism shown in FIG. 4 can be provided between the tension roll 16b and the take-up roll 17 on the long resin film conveyance path instead of the porous roll 18 shown in FIGS. The doctor blade 41 is provided with the above-described liquid supply pump and pipe 38 and can supply organic liquid from the outside of the casing.

  FIG. 5 is a side view schematically showing an example of the organic liquid application mechanism. A container 51 filled with the organic liquid L, a guide roll 52 for allowing the metal thin film multilayer substrate S to pass through the container 51, and two opposing metal sandwiching the metal thin film multilayer substrate S that has passed through the container 51 outside the container 51 This is an organic liquid application mechanism composed of a nip roll 53. By allowing the metal thin film multilayer substrate S to pass through the organic liquid, it is possible to form an organic liquid film on the surface of the metal thin film of the metal thin film multilayer substrate S. Specifically, the metal thin film multilayer substrate S is guided by the guide roll 52, passes through the container 51 filled with the organic liquid, and after passing, the metal thin film multilayer substrate S is sandwiched by the nip roll 53, and the film thickness of the organic liquid film is reached. Is to adjust. A coolant such as water circulates in the nip roll 53 and is cooled. The guide roll 52 is appropriately arranged so that the metal thin film laminated substrate S passes through the container 51, and is not limited to the arrangement shown in FIG. The guide roll 52 and the nip roll 53 rotate following the conveyance of the metal thin film multilayer substrate S. Since the organic liquid film is formed on both surfaces of the metal thin film laminated substrate S, there is no problem such as scratches on the surface of the metal thin film even if it is sandwiched between the nip rolls 53. The nip roll 53 can be appropriately selected from hard chrome plated stainless steel or rubber.

  The organic liquid supply mechanism shown in FIG. 5 can be provided between the tension roll 16b and the take-up roll 17 on the transport path of the long resin film instead of the porous roll 18 shown in FIGS.

  FIG. 6 is a side view schematically showing an example of the organic liquid application mechanism. An organic liquid is applied to the metal thin film laminated substrate S by the slit coater 61.

  If the film thickness of the organic liquid film is too thin, the copper surfaces come into contact with each other. If the film is too thick, loosening after winding is likely to occur. Therefore, it is preferably several tens of nm to 5 μm. The film thickness of the organic liquid can be adjusted by the pressure of the pressure contact of the porous roll 18 or the supply amount of the organic liquid in the case of application by the porous roll 18. In the case of coating by the doctor blade 41, the coating thickness of the organic liquid film can be adjusted by the gap between the doctor blade 41 and the metal thin film multilayer substrate S and the transport speed of the metal thin film multilayer substrate S. In the case of coating by the slit coater 61, the coating thickness of the organic liquid film is adjusted by the distance between the slit coater 61 and the metal thin film multilayer substrate S, the width of the slit 62 of the slit coater 61, and the transport speed of the metal thin film multilayer substrate S. it can.

The organic liquid may have specific vapor pressure and chemical properties. The vapor pressure of the organic liquid is preferably 1/100 or less of the atmospheric pressure during film formation. For example, if the atmospheric pressure during film formation is 0.1 Pa, the vapor pressure at 40 ° C. is 1 ×. It must be 10 ⁻³ Pa or less. It is preferable that the vapor pressure of the organic liquid is 1/100 or less of the pressure of the atmosphere at the time of film formation. This is because it is not contaminated with steam. In addition, organic liquids do not dissolve long resin films, do not corrode metal thin films, and have chemical characteristics that can be removed with a known method of solvent or alkaline degreasing solution before processing in the next step (electrolytic plating). do it.

  The viscosity of the organic liquid may be any viscosity that can be spread on the metal thin film laminated substrate S to form an organic liquid film. It may be a liquid organic liquid such as vacuum pump oil. Available as hydrocarbon or silicone vacuum pump (diffusion pump) oil, for example, ULVOIL (registered trademark) D-11, D-31, etc. of genuine vacuum pump oil of ULVAC vacuum pump be able to.

  It is necessary for the organic liquid L not to adhere or adhere between the front and back surfaces of the wound metal thin film laminated substrate S. The organic liquid L must not be a liquid adhesive and cannot be an organic liquid that undergoes a curing reaction.

  As the long resin film F that can be used in the present invention, a polyimide film, a polyamide film, a polyethylene terephthalate film, a polyethylene terephthalate film, or the like can be appropriately selected.

(Example)
For the long resin film, Kapton (registered trademark) manufactured by Toray DuPont having a width of 500 mm and a thickness of 25 μm was used. As the vacuum film forming apparatus, the vacuum film forming apparatus 10 shown in FIG. 1 was used. Among the two sputtering cathodes of the vacuum film forming apparatus 10 of FIG. 1, the sputtering cathode 15a on the unwinding roll side has a nickel-chromium alloy (nickel 93 mass% -chromium 7 mass%) target, and the sputtering on the winding roll side. A copper target was attached to the cathode 15b. The inside of the vacuum film-forming apparatus housing was depressurized to 2 × 10 ⁻⁴ Pa or less to obtain an ultimate pressure. Argon gas was introduced into the vacuum film forming apparatus housing 12 until the pressure reached 0.2 Pa. In the film formation on the first surface of the long resin film F, since the organic liquid was not applied, the porous roll 18 was not brought into contact with the long resin film F and the supply of the organic liquid was stopped. A nickel-chromium alloy layer of 70 mm and a copper layer of 1000 mm were formed. The long resin film F taken up by the take-up roll 17 was taken out from the vacuum film forming apparatus 10 and attached to the take-up roll 13 with the front and back sides of the long resin film F reversed. Subsequently, after forming a nickel-chromium alloy and copper in the same manner as in the first surface, the back surface (second surface) of the first surface is made to adhere to the porous thin film 18 and the organic liquid film. Formed and then wound up. The film thickness of the organic liquid film was about 1.3 μm and was measured by a gravimetric method . The gravimetric method is to estimate the coating film thickness from the change in the weight of the substrate after application of the organic liquid and after cleaning. The organic liquid is ULVOIL (registered trademark) D-11 manufactured by ULVAC, the kinematic viscosity is 0.3 St, the specific gravity is 0.91, and the vapor pressure at 25 ° C. is about 4 × 10 ⁻⁴ Pa. The vapor pressure of D-11 is sufficiently low, 1 of 1000 of the atmospheric pressure during sputtering. After winding, the film is taken out from the vacuum film forming apparatus 10 into the atmosphere and left for one day. Then, the oil film is unwound and the oil film is washed with alkali. Subsequently, copper having a thickness of 8 μm is deposited on the copper films on both sides of the metal thin film multilayer substrate S Electroplated. A nickel-chromium alloy and copper film on one side was chemically etched with an aqueous ferric chloride solution, and the presence or absence of a pinhole on one side was observed with an optical microscope with transmitted light. When ten arbitrary 1 mm squares were observed, pinholes were not confirmed.

(Comparative example)
A metal thin film laminated substrate was formed on both sides under the same conditions as in the Examples except that no organic liquid film was formed. Further, similarly to the example, copper was electroplated on the copper films on both sides. Similarly to the example, a nickel-chromium alloy and copper film on one side was chemically etched with an aqueous ferric chloride solution, and the presence or absence of a pinhole on one side was observed with an optical microscope with transmitted light. When ten arbitrary 1 mm squares were observed, about 120 pinholes were confirmed.

  In the example, since the organic liquid film was formed on one surface of the metal thin film laminated substrate, there was no bonding on the front and back after winding, and as a result, no pinhole was generated. On the other hand, in the comparative example, since the organic liquid film was not formed, bonding on the front and back of the metal thin film laminated substrate after winding occurred, resulting in a pinhole in the copper electroplating film.

These are side views which show an example of the vacuum film-forming apparatus of this invention. These are side views which show an example of the vacuum film-forming apparatus of this invention. (A) is a side view which shows typically an example of the organic substance liquid application | coating mechanism of this invention, (b) is a front view. These are side views which show typically an example of the organic substance liquid application | coating mechanism of this invention. These are side views which show typically an example of the organic substance liquid application | coating mechanism of this invention. These are side views which show typically an example of the organic substance liquid application | coating mechanism of this invention.

Explanation of symbols

10. Vacuum film forming apparatus 11. Vacuum film forming apparatus 12. Vacuum film forming apparatus casing 13. Unwinding roll 14. Can roll 15a. Sputtering cathode 15b. Sputtering cathode 16a. Tension roll 16b. Tension roll 17. Winding roll 18. Porous roll 34. Liquid supply pump 36. Rotary joint 38. Oil feed pipe 39. Liquid tank 41. Doctor blade 51. Container 52. Guide roll 53. Nip roll 61. Slit coater 62. Slit

Claims (7)

In the manufacturing method of a metal thin film laminated substrate in which a metal thin film is vacuum-deposited on both sides of a long resin film,
After a metal thin film is vacuum-deposited on both sides of the long resin film, an organic liquid film is applied and formed on the surface of at least one of the metal thin films using an organic liquid coating mechanism, and then the long resin film A method for producing a metal thin film laminate substrate, comprising winding a metal thin film laminate substrate having metal thin films laminated on both sides of the substrate.   2. The method for producing a metal thin film laminated substrate according to claim 1, wherein the organic liquid film is applied by a porous roll or a doctor blade.   The method for producing a metal thin film multilayer substrate according to claim 1, wherein the vapor pressure of the organic liquid is 1/100 or less of the pressure of the atmosphere at the time of film formation in the vacuum film formation apparatus. In a vacuum film forming apparatus equipped with a vacuum film forming mechanism facing the unwinding roll, can roll, take-up roll, and can roll of the long resin film,
An organic liquid application mechanism for forming an organic liquid film by applying an organic liquid film on at least one surface of the long resin film between the can roll and the take-up roll on the transport path of the long resin film. A vacuum film forming apparatus comprising:   5. The vacuum film forming apparatus according to claim 4, wherein the organic liquid film is applied by a porous roll in the organic liquid application mechanism.   5. The vacuum film forming apparatus according to claim 4, wherein the organic liquid film is applied by a doctor blade in the organic liquid application mechanism. A container filled with an organic liquid; a guide roll for allowing the metal thin film multilayer substrate to pass through the container; and a metal thin film multilayer substrate outside the container and after passing through the container. The vacuum film-forming apparatus according to claim 4, comprising two nip rolls facing each other.

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