JP2024070178A - Multilayer dry film manufacturing method and manufacturing device - Google Patents

Abstract

[Problem] To provide a method and an apparatus for manufacturing a multilayer dry film that can prevent intermixing between layers and prevent the inclusion of foreign matter or the occurrence of scratches. [Solution] The method and apparatus for manufacturing a multilayer dry film according to a first aspect of the present invention includes the steps of forming a first film on a first film that serves as a base, forming a protective film on the surface of the first film, removing the protective film, and forming a second film on the surface of the first film from which the protective film has been removed. [Selected Figure] Figure 1

Description

The present invention relates to a dry film used for printed wiring boards, etc., and in particular to a manufacturing method and manufacturing apparatus for a multi-layered dry film.

The dry film comprises at least a first film that serves as a base, and a resin composition layer formed by drying a liquid. Such dry films are used in the form of solder resists and interlayer insulating layers for printed wiring boards used in electronic devices, etc.

Some dry films have a multi-layer structure in which multiple layers are laminated. To manufacture a multi-layer dry film, for example, there is a method in which multiple layers are simultaneously coated and formed, as shown in Patent Document 1, but there is a possibility that the layers may mix together at the interfaces.

On the other hand, as described in Patent Document 2, a method has been proposed in which a first layer is applied onto a first film, dried, and then a second layer is applied. With this method, there is no risk of the layers mixing together, but after the first layer is formed, there is a risk that foreign matter may adhere to or damage the surface of the first layer during transport to form the second layer.

Japanese Patent Application Laid-Open No. 9-223499 JP 2000-153597 A

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a method and apparatus for manufacturing a multilayer dry film that is free of intermixing between layers and prevents the inclusion of foreign matter and the occurrence of scratches.

In order to solve the above problem, the method for manufacturing a multilayer dry film according to the first aspect of the present invention is characterized by including the steps of: forming a first film on a first film serving as a base; forming a protective film on the surface of the first film; removing the protective film; and forming a second film on the surface of the first film from which the protective film has been removed.

Here, the "first film" is the base or substrate for producing the multilayer dry film, and is sometimes called the "carrier film."

In the present invention, after the first film is formed, a protective film is formed on its surface, so that even if the first film comes into contact with a transport roller or the like during transport before the second film is formed, foreign matter will not adhere to the surface of the first film or the surface will not be scratched.

The multilayer dry film according to the present invention can have a structure of three or more layers, in which case the above-mentioned steps are repeated. For example, when manufacturing a multilayer dry film with a three-layer structure, a step is added in which a protective film is formed on the surface of the second film, and the protective film is removed immediately before the formation of the third film.

The protective film is made of a solid film, and the step of removing the protective film can include a step of physically peeling off the protective film. In addition to physical peeling, the method of removing the protective film can also be a method of dissolving the solid film with a liquid.

Examples of solid films that can be used to form the protective film include polyethylene films, polytetrafluoroethylene films, polypropylene films, and surface-treated paper.

By using a solid film as a protective film, the surface of the first film is completely covered by the solid film until it is removed (peeled off), so the dry film on which the first film is formed can be wound up in a roll and stored. Then, by peeling off the solid film for the protective film just before forming the second film in another facility (line), the second film can be formed on the first film. It is also possible to continuously form the first film and the second film in one line.

In the step of forming the protective film, it is preferable to form the protective film so that its adhesive strength to the first film is weaker than that of the first film. By making the adhesive strength of the protective film weaker than that of the first film, the protective film can be removed smoothly and reliably.

The adhesive strength of the protective film can be adjusted by the amount of residual solvent and the composition of the first film. The amount of residual solvent in the first film can be adjusted, for example, by changing the drying conditions, such as the temperature and speed, when drying the first film. In addition, the tack performance (adhesive strength) on the surface of the first film can be adjusted by changing the composition of the protective film itself.

The protective film can be formed by applying or spraying a liquid, and the step of removing the protective film can include the step of drying the protective film.

Here, the "drying process" can be carried out using a dryer that applies heat, or it can be done by natural drying.

By using a liquid as a protective film, it is expected that manufacturing costs and efficiency will be improved compared to using a solid film. Since it is a liquid, it dries and flows away, so it is not easy to protect the surface of the first film for a long period of time, but it is useful when the distance between the device that forms the first film (coater, dryer, etc.) and the device that forms the second film is relatively small.

The liquid that forms the protective film can be water or an organic solvent.

The first film and the second film can have the same composition. By stacking films of the same composition, the same layer is formed, making it easier to adjust the thickness of the layer. For example, when the multi-layer dry film is used for forming a solder resist, the overall thickness of the layer formed by combining the first film and the second film can be made thicker. For example, the overall thickness can be set to 20 to 500 μm.

The first film and the second film may have different compositions. By making the first film and the second film have different compositions, different layers are formed from each film, and each film can have a different function.

The method may further include a step of attaching a protective second film onto the second membrane. Here, the "second film" may be referred to as, for example, a "cover film" or the like, and covers and protects the opposite side of the first film from the time the multilayer dry film is shipped until it is used by the customer (e.g., a circuit board manufacturer).

The multilayer dry film manufacturing apparatus according to the second aspect of the present invention is characterized by including a first film forming unit that forms a first film on the surface of a first film that serves as a base; a protective film forming unit that forms a protective film on the first film; a film removing unit that removes the protective film; and a second film forming unit that forms a second film on the surface of the first film from which the protective film has been removed.

FIG. 1 is a schematic diagram showing the configuration of a multilayer dry film manufacturing apparatus according to a first embodiment of the present invention. FIG. 2 is a flow chart showing a process for manufacturing the multi-layer dry film according to the first embodiment of the present invention. 3A to 3C are cross-sectional views showing the state of the film at each stage of the manufacturing process of the multilayer dry film according to the first embodiment of the present invention. FIG. 4 is a schematic diagram showing the configuration of a multilayer dry film manufacturing apparatus according to a second embodiment of the present invention. FIG. 5 is a flow chart showing a process for manufacturing a multi-layer dry film according to a second embodiment of the present invention. 6A to 6C are cross-sectional views showing the state of a multi-layer dry film at each stage of a manufacturing process according to a second embodiment of the present invention.

The following describes in detail the embodiments of the present invention with reference to the drawings.

Multilayer dry films to which the present invention can be applied include those for forming interlayer insulating layers, photosensitive coverlays, solder resists, etc., and conductive films for flat panel displays. However, they are not limited to these.

Figure 1 is a schematic diagram showing the configuration of a manufacturing apparatus for a multilayer dry film 50 according to a first embodiment of the present invention. Figure 2 is a flowchart showing the manufacturing process of the multilayer dry film according to this embodiment. Figure 3 is a cross-sectional view showing the state of the film at each stage of the manufacturing process of the multilayer dry film according to this embodiment. Note that the letters A to F in the figures are common to Figures 1 to 3 and indicate each stage of the manufacturing process.

In the manufacturing apparatus for the multilayer dry film 50 (FIG. 3) according to this embodiment, the manufacturing line for forming the first film 13 includes a first film roll 10 for supplying the first film 11 that serves as a base, a coater 12 for applying a solution 13' that forms the first film 13 onto the first film 11, a dryer 14, a protective film roll 16 for supplying a protective film 18, and a storage roll 22 for winding up the film laminated with the protective film 18.

The manufacturing line for forming the second film 25 on the first film 13 includes a take-up roll 23 for peeling off the protective film 18 from the film wound around the storage roll 22, a coater 24 for applying a solution 25' for forming the second film 25 on the surface of the first film 13, a dryer 26, a second film roll 28 for supplying the second film 30, and a storage roll 34 for winding up the multilayer dry film in its final form.

The coater that forms the first film 13 and the second film 25 applies a resin composition solution, and examples of such coaters include a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, slot die coater, and spray coater. In particular, it is preferable to use a gravure coater or a slot die coater.

The amount of resin composition contained in the solution used to form the first film 13 and the second film 25 to be applied depends on the application of the first film 13 and the second film 25, but can be in the range of 0.1 to 500 μm, preferably 1 to 250 μm, in terms of film thickness after drying.

As the dryers 14 and 26, a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. can be used. Note that a convection oven is a method in which hot air inside the dryer is brought into countercurrent contact using a heat source that uses steam for air heating, and is blown onto the substrate from a nozzle. Drying conditions can be, for example, a drying temperature of 50 to 200°C and a drying time of 10 seconds to 15 minutes.

In the first embodiment described above, the manufacturing line for forming the first film 13 (upper side of FIG. 1) and the manufacturing line for forming the second film 25 (lower side of FIG. 1) are separate, but these lines can also be made into one continuous line.

Next, a method for manufacturing a multilayer dry film according to a first embodiment of the present invention will be described. As shown in FIG. 1, a first film 11 drawn from a first film roll 10 is fed into a coater 12, and a solution 13' for forming a first film 13 is applied onto the first film 11. A thermoplastic film such as a polyester film having a thickness of 2 to 150 μm is used as the first film 11. The solution 13' is a curable resin composition whose viscosity is adjusted by the amount of solvent, and is applied so that the film thickness after drying is, for example, 10 μm.

The first film 11 coated with the solution 13' is dried in a hot air circulation dryer 14 at, for example, 90°C for 30 minutes to evaporate the solvent and form the first film 13 of the resin composition. In addition to the above, the drying conditions can also be a drying temperature of 50 to 200°C and a drying time of 10 seconds to 15 minutes.

Then, the protective film 18 is attached to the surface of the first film 13 by passing it between a pair of laminating rollers 20, and the protective film 18 is wound up on a storage roll 22. Note that the conditions for laminating the protective film 18 are preferably, for example, a temperature of 20 to 80°C and a pressure of 0 to 1.0 MPa.

For example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. can be used as the protective film 18. By making the adhesive strength between the first film 13 and the protective film 18 smaller than the adhesive strength between the first film 13 and the first film 11, the protective film 18 can be peeled off easily.

Then, the protective film 18 is peeled off from the storage roll 22 by the winding roll 23, and a solution 25' for forming the second film 25 is uniformly applied to the exposed surface of the first film 13 by the coater 24. For example, the solution 25' is applied so that the film thickness of the second film 25 after drying is 25 μm. Then, in a hot air circulation dryer 26, it is dried, for example, at 90°C for 30 minutes, and the solvent is vaporized to form the second film 25 of a resin composition. In addition to the above, the drying conditions can be a drying temperature of 50 to 200°C and a drying time of 10 seconds to 15 minutes.

The composition of the second film 25 can be the same as that of the first film 13, but a different composition can also be used.

The first film 11, in which the first film 13 and the second film 25 are laminated, is passed between a pair of laminating rollers 32, so that the second film 30 is attached to the surface of the second film 25. Note that the conditions for laminating the second film 30 are preferably, for example, a temperature of 20 to 80°C and a pressure of 0 to 1.0 MPa.

The above steps complete the production of the multilayer dry film 50. The second film 30 can be a polyethylene film, a polypropylene film, or the like, but it is preferable that the adhesive strength with the dry coating film (13, 25) is weaker than that of the first film 11. The manufactured multilayer dry film 50 is wound on a storage roll 34 and stored in a state ready for shipment.

The functions and compositions of the first film 11, protective film 18, and second film 30 used in the present invention are described in further detail below.

The first film 11 is a substrate onto which the first film 13, which is a resin composition, is applied, and supports the applied resin composition (coating film). After the multilayer film is completed, the first film 11 may be peeled off from the resin layer (13, 25).

Examples of the first film 11 include polyimide resin, polyamideimide resin, polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polycarbonate resin, acrylonitrile-butadiene-styrene (ABS) resin, polystyrene, cycloolefin polymer, liquid crystal polymer, polyether ether ketone, polyphenylene sulfide resin, polyphenylsulfone, polyphenylene ether, acrylic resin such as poly(methyl meth)acrylate, polyvinylidene fluoride resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polyethylene resin, polypropylene resin, urethane resin, silicon, silicon carbide, gallium nitride, sapphire, ceramics, glass, glass epoxy resin, glass polyimide, paper phenol, diamond-like carbon, alumina, polyester fiber, polyamide fiber, synthetic fiber such as polyaramid fiber, inorganic fiber such as carbon fiber, natural fiber such as cellulose nanofiber, etc. These first films 11 are preferably insulating, and porous ones can be used. The first film 11 may be made of a single material or may be a laminate of multiple materials.

The first film 11 may be made of a base material made of synthetic fibers such as polyester fibers, polyamide fibers, and aramid fibers, or natural fibers such as cotton and hemp. The fibers may be pre-processed.

The first film 11 may be made of a material that is often used as a carrier film when forming conductive patterns such as electrical circuits, such as polyimide resin, polyethylene terephthalate, polyethylene naphthalate, glass, or cellulose nanofiber.

Among the above, the first film 11 is preferably made of a flexible resin material in order to impart flexibility to the laminate and obtain a foldable final product. Specifically, it is preferably in the form of a film or sheet formed by uniaxial or biaxial stretching or the like. Examples of the film or sheet-like first film 11 include a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate film, and a polybutylene terephthalate film.

Considering flexibility and bendability, the thickness of the first film 11 is usually about 1 to 1000 μm, preferably 5 to 500 μm, and more preferably 10 to 200 μm.

The first film 11 may have a role of forming a predetermined surface form on the surface on the side in contact with the first membrane 13. By appropriately adjusting the surface form of the first film 11, a resin layer having a desired surface form can be obtained. For example, a film can be used in which a filler is added to the resin when forming a film from the flexible resin material used for the first film 11 (kneading process), a matte coating (coating process), a blasting process such as sandblasting on the film surface, or a process such as hairline processing or chemical etching is performed. In particular, a film that has been subjected to a coating process can be preferably used. For example, a first film 11 having an intermediate layer containing particles on a support film can be used. The intermediate layer containing particles is not limited to a single layer, and may be laminated as a multiple layer of two or more layers.

The first film 11 may be subjected to a release treatment on the surface that contacts the first membrane 13. The release treatment may include, for example, a process of applying a coating liquid prepared by dissolving or dispersing a release agent such as wax, silicone wax, or silicon-based resin in an appropriate solvent to the surface of the first film 11 by a known coating means, and drying the coating liquid.

In addition to resins such as epoxy acrylate resin, the resin layer may contain, for example, a photopolymerization monomer or a photopolymerization initiator if the resin is to be photocured. On the other hand, for example, a thermosetting compound or a thermosetting catalyst may be added if the resin is to be heat cured. In addition, fillers, additives, etc. may be added as necessary.

As described above, a peelable second film 30 can be provided on the surface of the resin layer (second film 25) for the purpose of preventing dust from adhering to the surface of the resin layer. The second film 30 is peeled off from the resin layer (second film 25) before the dry film is laminated to an adherend such as a substrate at the customer's site to form an integral structure.

The second film 30 and the protective film 18 can be, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. The thickness of the second film 30 and the protective film 18 can be, for example, 10 μm to 150 μm.

The second embodiment of the present invention will now be described. FIG. 4 is a schematic diagram showing the configuration of a manufacturing apparatus for a multilayer dry film 150 (FIG. 6) according to the second embodiment of the present invention. FIG. 5 is a flowchart showing the manufacturing process of the multilayer dry film according to this embodiment. FIG. 6 is a cross-sectional view showing the state of the film at each stage of the manufacturing process of the multilayer dry film according to this embodiment. Note that the letters a to f in the figures are common to FIGS. 4 to 6 and indicate each stage of the manufacturing process.

The manufacturing apparatus for the multilayer dry film 150 according to this embodiment includes a first film roll 10 for supplying the first film 11, a coater 12 for applying a solution 13' for forming the first film 13 on the first film 11, a dryer 14, a protective liquid supplying device 102 for supplying the protective liquid 103, a dryer 104 for vaporizing the protective liquid 103, a coater 124 for applying a solution 125' for the second film 125 to the surface of the first film 13, a dryer 126, a second film roll 28 for supplying the second film 30, and a storage roll 134 for winding up the multilayer dry film 150 in its final form.

As shown in FIG. 4, the first film 11 pulled out from the first film roll 10 is fed into a coater 12, and a solution 13' that forms a first film 13 is applied onto the first film 11.

The first film 11 coated with the solution 13' is dried in a hot air circulation dryer 14 at, for example, 90°C for 30 minutes to evaporate the solvent and form a first film 13 of a resin composition. After that, a protective liquid 103 is applied or sprayed onto the surface of the first film 13, and the protective liquid 103 is dried and removed by the dryer 104 just before the coater 124.

The protective liquid 103 can be water or an organic solvent.

Then, a solution 125' for forming a second film 125 is uniformly applied to the exposed surface of the first film 13 by a coater 124. For example, the solution 125' is applied so that the film thickness of the second film 125 after drying is 25 μm. Then, in a hot air circulation dryer 126, the film is dried, for example, at 90°C for 30 minutes, and the solvent is evaporated to form a second film 125 of a resin composition.

As in the first embodiment, the composition of the second film 125 can be the same as that of the first film 13, or it can be a different composition.

The first film 11, in which the first film 13 and the second film 125 are laminated, is passed between a pair of laminating rollers 32, so that the second film 30 is attached to the surface of the second film 125. This completes the manufacture of the multilayer dry film 150. The manufactured multilayer dry film 150 is wound onto a storage roll 134 and stored in a state ready for shipment.

In the multilayer dry film manufactured by the method and apparatus according to the first and second examples, no scratches, contamination, or foreign matter was found at the interface between the layers. Furthermore, no mixing was found at the interface between the first and second films. Regarding mixing at the interface, the cross section was observed with a scanning electron microscope (SEM) at a magnification of 1000 times, and a determination was made as to whether or not there were any areas where the two coating layers could not be distinguished. As a result, no areas were observed where the two coating layers could not be distinguished.

Although the embodiments of the present invention have been described above, the present invention is in no way limited to the above embodiments, and can be modified as appropriate within the scope of the technical ideas expressed in the claims.

10: First film roll 11: First film 12, 24, 124: Coaters 14, 26, 104, 126: Dryer 13: First film 16: Protective film roll 18: Protective film 22: Storage roll 23: Take-up roll (for peeling)
25, 125: second film 28: second film roll 30: second film 32: lamination roller 102: protective liquid supply device 103: protective liquid 34, 134: storage roll 50, 150: multi-layer dry film

Claims (10)

A method for manufacturing a multilayer dry film, comprising:
forming a first membrane on a base first film;
forming a protective film on a surface of the first film;
removing the protective film;
and forming a second film on the surface of the first film from which the protective film has been removed. The protective film is made of a solid film,
2 . The method for producing a multilayer dry film according to claim 1 , wherein the step of removing the protective film includes a step of physically peeling off the protective film. The method for manufacturing a multilayer dry film according to claim 2, characterized in that in the step of forming the protective film, the protective film is formed so that its adhesive strength to the first film is weaker than that of the first film. The method for manufacturing a multilayer dry film according to claim 3, characterized in that the adhesive strength of the protective film is adjusted by at least one of the amount of residual solvent and the composition of the first film. The protective film is formed by applying or spraying a liquid,
The method for producing a multilayer dry film according to claim 1 , wherein the step of removing the protective film includes a step of drying the protective film. The method for manufacturing a multilayer dry film according to claim 5, characterized in that the liquid forming the protective film is water or an organic solvent. The method for manufacturing a multilayer dry film according to any one of claims 1 to 6, characterized in that the first film and the second film have the same composition. The method for manufacturing a multilayer dry film according to any one of claims 1 to 6, characterized in that the first film and the second film have different compositions. The method for manufacturing a multilayer dry film according to any one of claims 1 to 6, further comprising a step of attaching a second protective film onto the second film. An apparatus for manufacturing a multi-layer dry film, comprising:
a first film forming unit that forms a first film on a surface of a first film serving as a base;
a protective film forming unit that forms a protective film on the first film;
a film removing unit that removes the protective film;
a second film forming section that forms a second film on the surface of the first film from which the protective film has been removed.

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