TW201429379A - Multilayer film and shielded printed wiring board - Google Patents

Abstract

Provided is a multilayer film which has good embeddability and processability and is capable of adequately controlling the adhesive power of a transfer film with respect to a transfer-receiving layer.This multilayer film comprises: a transfer film (6) which comprises an inner resin layer (62) and outer resin layers (63) that are respectively laminated on one surface and the other surface of the inner resin layer (62), and in which a recessed and projected pattern (61) is formed on the outer surface of at least one of the outer resin layers (63)and a transfer-receiving layer (7) which is removably laminated on the outer surface of the transfer film (6), on said outer surface the recessed and projected pattern (61) being formed, and which is provided with a transferred pattern (71) that is formed by means of the recessed and projected pattern (61). The inner resin layer (62) is formed of a polyethylene terephthalate, and the outer resin layers (63) are formed of a polybutylene terephthalate.

Description

Laminated film and mask printed wiring board

The present invention relates to a laminated film and, in more detail, a laminated film for a mask film that shields electromagnetic waves such as an electronic device, and a mask printed wiring board.

The mask printed wiring board has been previously used for a portable device, a personal computer, etc., which is provided on a circuit board such as a flexible wiring board for the purpose of suppressing noise or electromagnetic waves emitted to the outside by a mask. There is a mask film.

Generally, the above-mentioned mask printed wiring board is manufactured in the following manner. First, a laminated film in which a coating film (transfer layer) is formed by coating a resin on a single surface of a release film (transfer film) with a release agent layer, and a mask layer is applied to the cover film side to form a mask. Cover film. A mask printed wiring board having a base member on which a ground wiring pattern and a signal wiring pattern are formed and laminated on the base member and exposed to a part of ground is formed by bonding a mask film to a printed wiring board and hot pressing to form a mask printed wiring board. An insulating film of a wiring pattern. The mask film has a conductive adhesive layer on the bonding surface with the printed wiring board, and the conductive adhesive layer is embedded in the portion of the insulating film where the ground wiring pattern is exposed during hot pressing. Thereby, the ground wiring pattern is electrically connected to the mask layer, and the electromagnetic wave mask function is further improved.

The release film used in the above production process is used in various applications, for example, Patent Documents 1 and 2.

In Patent Document 1, a pre-dip rush in the production of a copper clad laminate is disclosed. In the release film used in the pressing step, the release film is provided with a release agent layer on one side or both sides of the polyester-based foam film. Patent Document 2 discloses a release film having an embossing, and the embossed surface roughness (Rz: ten-point average roughness) of the release film is 5 μm or more and 20 μm or less before the press step, and after the press process The release film is used in a press process of a circuit board in the range of 2 μm or more and 8 μm or less.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-1726

Patent Document 2: Japanese Laid-Open Patent Publication No. 2008-246882

However, according to Patent Documents 1 and 2, the release film is used as a cushioning material in the press process of the circuit board. Therefore, since the release property of the release film with respect to the transfer layer is too high, sufficient adhesion may not be obtained. . Further, in general, the release film is formed of a layer of resin, and under some conditions, the shape followability of the release film with respect to the cover film to be bonded is lowered, and therefore, the portion of the printed wiring board from which the ground wiring pattern is exposed from the insulating film is removed. When it is narrow, it may result in insufficient conductivity of the conductive adhesive layer.

In order to solve the above problems, an object of the present invention is to provide a laminated film which can obtain good embedding property and workability and can appropriately control the adhesion of a transfer film to a transfer layer.

The laminated film of the present invention is characterized by comprising: a transfer film, An inner resin layer and an outer resin layer laminated on one surface and the other surface of the inner resin layer, and a concave-convex pattern formed on an outer surface of at least one of the outer resin layers; and a transfer layer detachably And a transfer pattern formed by the uneven pattern formed on the outer surface of the transfer film on which the uneven pattern is formed, wherein the inner resin layer is formed of polyethylene terephthalate, and the outer resin layer Formed from polybutylene terephthalate.

According to the above configuration, in the transfer film, an outer resin layer formed of polybutylene terephthalate is laminated on both surfaces of the inner resin layer formed of polyethylene terephthalate. Thereby, the followability of the transfer film with respect to the shape change of the transfer layer is improved, so that good embedding property can be obtained. In addition, by laminating the inner resin layer formed of polyethylene terephthalate, even if the outer surface of the outer resin layer expands and contracts in the surface direction due to factors such as temperature changes, the inner resin layer also passes through the inner resin layer. The deformation of the outer resin layer can be alleviated. In addition, since the outer resin layer is laminated on both surfaces of the inner resin layer, the force of expanding and contracting the outer surface of the outer resin layer in the surface direction can be canceled, and the deformation of the transfer film can be further reduced. Therefore, when the mask film having the laminated film of the present invention is bonded to the printed wiring board and hot pressed, problems due to deformation of the laminated film can be prevented.

Further, by forming the concavo-convex pattern and the transfer pattern on the bonding surface of the transfer film and the transferred layer, the adhesion of the transfer film to the transferred layer can be improved due to the anchoring effect, and the immersion in the liquid medicine can be prevented. Usually, the liquid medicine enters between the transfer film and the transferred layer in the subsequent process.

Further, the laminated film of the present invention may have the following configuration, that is, The arithmetic mean roughness (Ra) of the uneven pattern formed on the outer resin layer is 0.2 μm to 2.5 μm.

According to the above configuration, the adhesion of the transfer film to the transferred layer can be optimized.

In addition, the laminated film of the present invention may have a structure in which the variation of the arithmetic mean roughness (Ra) of the uneven pattern formed on the outer resin layer is 0.50 μm or less.

According to the above configuration, the structure in which the variation in the average roughness is 0.50 μm or less can stabilize the adhesion of the respective bonding surfaces between the transfer film and the transfer layer.

Further, in the laminated film of the present invention, the transfer film may be formed by laminating the outer resin layer 63 on both surfaces of the inner resin layer by an extrusion lamination method, and two irregularities are formed on at least one of the surfaces. The rolls are pressurized.

According to the above configuration, the laminate is formed by pressurization using two rolls having irregularities formed on at least one of the roll faces, and the laminate is laminated with the outer resin layer on both sides of the inner resin layer by extrusion lamination. Thereby, it is possible to reduce variations in the arithmetic mean roughness of the uneven pattern of the outer resin layer and the transfer pattern of the transfer layer, and it is possible to stabilize the adhesive force and the peeling force of the transfer film and the transferred layer. The transfer pattern of the transfer layer is formed by a concavo-convex pattern. Further, according to the above configuration, after the laminated film is placed on the printed wiring board and heated and pressurized, the adhesive force of the transfer film with respect to the transferred layer is remarkably lowered. Thereby, the operation of peeling the transfer film from the transfer layer is facilitated.

Further, the laminated film of the present invention may be configured such that the above-mentioned transfer is performed The layer is the protective layer in the mask film having the conductive adhesive layer, the metal layer, and the protective layer, and the metal layer is laminated on the conductive adhesive layer, and the protective layer is laminated on the metal layer.

According to the transfer film of the above configuration, since the transfer film can be prevented from being deformed, lamination to the mask film can be easily performed. In addition, since the transfer film has good embedding property, it is possible to suppress voids formed when the conductive adhesive is embedded in the position where the ground wiring pattern is exposed in the insulating film, and it is possible to suppress a decrease in the conduction performance of the ground wiring pattern.

Further, the laminated film of the present invention may be configured such that the transferred layer is the protective layer in the mask film having the conductive adhesive layer and the protective layer, and the protective layer is laminated on the metal layer.

According to the above configuration, since the transfer film can be prevented from being deformed, lamination to the mask film can be easily performed. In addition, since the transfer film has good embedding property, it is possible to suppress voids generated when the conductive adhesive is embedded in the position where the ground wiring pattern is exposed in the insulating film, and it is possible to suppress a decrease in the conduction performance of the ground wiring pattern.

In the mask printed wiring board of the present invention, the mask film is bonded to the printed wiring board.

According to the above configuration, it is possible to obtain a mask printed wiring board capable of preventing the problem caused by the deformation of the laminated film when the mask film is bonded to the printed wiring board and being hot-pressed, and The operation of peeling the printing film from the above protective layer is easy to carry out.

1‧‧‧ mask film

2‧‧‧ basement membrane

2a‧‧‧Insulation Removal Department

3‧‧‧Printed circuit

3a‧‧‧Signal circuit

3b‧‧‧ Grounding circuit

3c‧‧‧ Non-insulated parts

4‧‧‧Insulation film

4a‧‧‧Insulation Removal Department

5‧‧‧Base film

6‧‧‧Transfer film

6b‧‧‧ release layer

7‧‧‧Transfer layer

8‧‧‧Electromagnetic wave mask

8a‧‧‧Binder layer

8b‧‧‧ metal layer

9‧‧‧Mask film body

10‧‧‧ mask film

21‧‧‧The inner resin layer roller

22‧‧‧film extruder

23‧‧‧ embossing roller

24‧‧‧casting rolls

25‧‧‧Transfer film roller

61‧‧‧ concave pattern

61a‧‧‧ convex

61b‧‧‧ recess

71‧‧‧Transfer pattern

71a‧‧‧ top

71b‧‧‧ bottom

100‧‧‧Mask flexible printed wiring board

101‧‧‧Mask flexible printed wiring board

Fig. 1 is an explanatory view of a laminated film of the embodiment.

FIG. 2 is an explanatory view showing a method of manufacturing the transfer film of the embodiment.

3 is an explanatory view showing a state in which a conductive adhesive is embedded in a ground circuit of a mask printed wiring board, and the laminated printed wiring board of the present embodiment is used.

4 is an explanatory view showing a state in which a conductive adhesive is embedded in a ground circuit of a mask printed wiring board, and the laminated printed wiring board of the present embodiment is used.

FIG. 5 is an explanatory view showing a state in which the printed wiring board is masked in a state in which the transfer film of the embodiment is peeled off.

Fig. 6 is an explanatory view showing a mask flexible printed wiring board of the embodiment.

Fig. 7 is an explanatory diagram of a test method for an evaluation test of peel strength.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The laminated film 1 shown in Fig. 1 includes a transfer film 6 having an inner resin layer 62 and outer resin layers 63 laminated on one surface and the other surface of the inner resin layer 62, respectively, and at least one of the outer resin layers 63. The outer surface of the person is formed with a concave-convex pattern 61; and the transferred layer 7 is detachably laminated on the outer surface of the transfer film 6 on which the concave-convex pattern 61 is formed, and has a transfer pattern formed by the concave-convex pattern 61 71. Further, in the present embodiment, the transfer film 6 and the transferred layer 7 are laminated via the release agent layer 6b formed by applying a release agent.

The inner resin layer and the outer resin layer may be bonded by a binder, or may be laminated by heat welding or the like without using a binder. When laminating by heat fusion bonding, a laminated film which is well adhered between the inner resin layer and the outer resin layer can be easily produced by an extrusion lamination method. In addition, the two outer resin layers preferably have phases The same layer thickness, but is not limited to this.

(transfer film 6)

As shown in FIG. 1, the transfer film 6 has outer resin layers 63 and 63 laminated on one surface and the other surface of the inner resin layer 62, respectively. In the present embodiment, the inner resin layer 62 is formed of PET (polyethylene terephthalate) resin, and the outer resin layers 63 and 63 are each formed of PBT (polybutylene terephthalate) resin. Here, Table 1 shows a comparison of general physical properties and characteristics of PBT resin and PET resin.

As shown in Table 1, it is understood that the PBT resin and the PET resin are materials having very similar physical properties, layering properties, and mechanical properties.

Therefore, by forming the inner resin layer 62 from the PET resin, the outer resin layers 63 and 63 are formed of the PBT resin, so that the outer resin layer 63 is similarly shrunk and expanded, for example, even when the temperature of the transfer film 6 changes, and curling or the like can be prevented. Deformation. Moreover, since the outer resin layer 63 is formed of PBT resin, it is easy to change the shape when pressure or the like is applied. That is, the outer resin layer 63 easily changes in shape following the laminated transfer layer, and good embedding property can be obtained.

Further, by crystallization and using the resin of the inner resin layer 62 and the outer resin layer 63, the heat shrinkage rate can be reduced to reduce the deformation of the transfer film 6.

Preferably, the material of the inner resin layer 62 is made of PET resin, and the material of the outer resin layer 63 is made of PBT resin, but is not limited thereto. In addition, for example, polyethylene naphthalate, polyimide, polyethylene, polypropylene, polyvinyl chloride, nylon, polycarbonate, polymethylpentene may be cited as the outer resin layer 63. The material may, for example, be polypropylene, polymethylpentene, polyethylene naphthalate or polyimine as the material of the inner resin layer 62. The lower limit of the layer thickness of the inner resin layer 62 is preferably 6 μm, more preferably 8 μm, still more preferably 25 μm. Further, the upper limit is preferably 50 μm, and more preferably 38 μm. The lower limit of the layer thickness of the outer resin layer 63 is preferably 6 μm, and more preferably 8 μm. Further, the upper limit is preferably 30 μm, more preferably 20 μm, still more preferably 12 μm.

In addition, as shown in FIG. 1, on the laminated surface on which the outer resin layer 63 and the transfer layer 7 are laminated, a concave-convex pattern 61 (a convex portion 61a and a concave portion 61b) each having a plurality of uneven shapes is formed on the entire surface.

(Transfer film 6: manufacturing method)

Next, a method of manufacturing the transfer film 6 will be described. The transfer film 6 is formed by laminating an outer resin layer 63 on both surfaces of the inner resin layer 62 by an extrusion lamination method, and is pressurized by using two rolls in which at least one of the surfaces thereof is formed with irregularities.

Specifically, first, the inner resin layer 62 is formed into a film shape by extruding a PET resin by an extruder (extrusion width: 1300 mm) having a temperature of 280 ° C to 290 ° C, and is wound up on a roll. Then, as shown in FIG. 2, the inside of the PET resin is taken up. The side resin layer is fed by the roller 21, and the film-formed inner resin layer 62 is supplied between the embossing roll 23 and the casting roll 24, and the arithmetic mean roughness of the embossing roll 23 is 0.2 μm - 2.5 μm. On the other hand, PBT was extruded by setting two film extruders 22, 22 (effective extrusion width: 1300 mm) having a temperature of 220 ° C to 260 ° C, and the extruded film-like outer resin layers 63, 63 were embossed. The roller 23 and the casting roller 24 are supplied so that the outer resin layers 63, 63 are laminated on one surface and the other surface of the inner resin layer 62, respectively. The laminate of the inner resin layer 62 and the outer resin layers 63, 63 is pressurized between the embossing roller 23 and the casting roller 24, and arithmetic is formed on the outer surface of the outer resin layer 63 laminated on the embossing roller 23 side. The uneven pattern 61 having an average roughness of 0.2 μm to 2.5 μm. Thus, the transfer film 6 on which the outer resin layers 63, 63 (PBT) are laminated on both sides of the inner resin layer 62 (PET resin) is formed, and the uneven image 61 can be formed on the transfer film 6. The transfer film 6 formed as described above is wound up on the transfer film roll 25 and stored. It is also possible to laminate the outer resin layer 63 layer by layer by one film extruder 22.

In addition, in FIG. 2, the cooling roller etc. are abbreviate|omitted, and the resin after extrusion|curing can be suitably cooled, and the edge part of film-form resin is shaping|molding.

Further, the above manufacturing method can be appropriately changed depending on factors such as materials, design, and the like.

The uneven pattern 61 is preferably formed on the entire outer surface of the outer resin layer 63, but is not limited thereto. Further, the pattern of the concavo-convex pattern 61 is not limited, and for example, a pattern formed by repeating a predetermined pattern may be used, or a pattern in which irregularities are randomly formed may be used. Further, when the two-layer outer resin layers 63 and 63 form the uneven pattern 61, the two embossing rolls 23 may be used for lamination processing.

In addition, in order to form a concave-convex pattern, in order to reduce the uneven shape of the production batch The deviation is preferably embossing, which can be continuously formed into a predetermined shape by the uneven shape formed on the embossing roll, compared to sandblasting or chemical matte coating. In addition, when a mask film using an embossed transfer film is placed on a printed wiring board and heated and pressed to form a mask printed wiring board, the adhesion of the transfer film to the transferred layer is large. decline. Thereby, the operation of peeling the transfer film from the transfer layer is facilitated.

(transferred layer 7)

As shown in Fig. 3, in the present embodiment, the transfer layer 7 is a protective layer of a mask film having a conductive adhesive layer 8a, a metal layer 8b, and a protective layer, and the metal layer 8b is laminated on the conductive adhesive. On the agent layer 8a, the protective layer is laminated on the above metal layer 8b. That is, the transferred layer 7 is a protective layer composed of a coating film of a cover film and an insulating resin.

Mention may be made of polyester, polybenzimidazole, aramid, polyimine, polyamidamine, polyether phthalimide, polyphenylene sulfide (PPS), polyethylene naphthalate (PEN). Etc. as a material constituting the cover film.

When heat resistance is not required, an inexpensive polyester film is preferably used. When flame resistance is required, a polyphenylene sulfide film is preferably used, and when heat resistance is further required, an aramid film or a polyimide film is preferably used.

The insulating resin may be any resin having an insulating property, and examples thereof include a thermosetting resin and an ultraviolet curable resin. Examples of the thermosetting resin include a phenol resin, an acrylic resin, an epoxy resin, a melamine resin, an anthracene resin, and an acrylic modified oxime resin. Examples of the ultraviolet curable resin include an epoxy acrylate resin, a polyester acrylate resin, and a methacrylate modified product. In addition, as a curing method, as long as the material can be solidified Alternatively, for example, it may be any one of heat curing, ultraviolet curing, electron beam curing, and the like.

Further, from the viewpoint of preventing the peeling of the outer resin layer 63 due to colorless transparency, it is preferable to add a pigment (for example, white or the like) to color the resin.

Further, the lower limit of the thickness of the transferred layer 7 is preferably 1 μm, more preferably 3 μm, still more preferably 5 μm. Further, the upper limit of the thickness of the transferred layer 7 is preferably 15 μm, more preferably 10 μm, still more preferably 7 μm. Further, the transferred layer is not limited to the protective layer of the mask film, and can be used for a film such as a cover film or an anti-glare film.

Further, the transferred layer 7 is not limited to a single layer structure, and may have a multilayer structure. For example, it may be a two-layer structure in which a hard layer and a soft layer on the side of the transfer film 6 are sequentially applied, and the hard layer on the side of the transfer film 6 is made of a resin excellent in abrasion resistance and blocking resistance, and the soft material The layer is composed of a resin having excellent cushioning properties.

In the present embodiment, the transfer layer 7 is applied to the transfer layer by applying the release agent layer 6b to one surface of the transfer film 6 (the surface of the outer resin layer 63 on which the uneven pattern 61 is formed). 7 resin formed. Thus, in a state where the transfer layer 7 is detachably laminated on the transfer film 6, the uneven pattern 61 of the transfer film 6 is transferred to the transferred layer 7 to form a transfer pattern 71 (top 71a, bottom) 71b). That is, the bottom portion 71b of the transfer pattern 71 is formed by the convex portion 61a of the concave-convex pattern 61, and the top portion 71a of the transfer pattern 71 is formed by the concave portion 61b of the concave-convex pattern 61 (refer to FIG. 1).

More specifically, in a state in which the transfer layer 7 is detachably laminated on the transfer film 6, the convex portion 61a of the concave-convex pattern 61 is engaged with the bottom portion 71b of the transfer pattern 71, and the concave portion 61b of the concave-convex pattern 61 is rotated. The top 71a of the printed pattern 71 is engaged. As a result, the anchoring effect improves the adhesion of the transfer film 6 to the transferred layer 7, and it is possible to prevent the transfer film 6 from being peeled off from the transferred layer 7 in a usual subsequent step such as a immersion chemical solution, thereby preventing the film from being peeled off. In the process, the chemical liquid enters between the transfer film 6 and the transferred layer 7.

Further, after the transfer film 6 is peeled off, the arithmetic mean roughness of the surface of the transfer layer 7 on which the transfer pattern 71 is provided is preferably 0.2 μm to 2.5 μm, and more preferably 0.5 μm to 1.7 μm. When it is less than 0.2 μm, the adhesive force of the transfer film with respect to the transfer layer becomes too small, and the transfer film may be peeled off from the transfer layer in a usual subsequent process such as a dipping chemical. When it is more than 2.5 μm, when the transfer film is peeled off from the transfer layer, the transfer layer itself may be damaged due to excessive adhesion. In addition, the deviation of the arithmetic mean roughness of the surface of the transfer layer 7 on which the transfer pattern 71 is provided after the transfer film 6 is peeled off may be 0.50 μm or less. By setting the deviation of the arithmetic mean roughness to 0.50 μm or less, the adhesive force in each portion of the transfer surface of the transfer film 6 and the transfer layer 7 can be stabilized.

Further, the method of laminating the transfer film 7 on one surface of the transfer film 6 is preferably a coating method, but lamination, extrusion, dipping, or the like may be used as a layer forming method other than coating.

(release agent layer 6b)

The release agent layer 6b is not particularly limited as long as the transfer film 6 is a layer having releasability with respect to the transfer layer 7, and for example, a release agent of a hydrazine or a non-quinone type can be used. In addition, the maximum thickness of the release agent layer 6b is preferably smaller than the height of the concave-convex pattern 61 in the transfer film 6. When the release agent is applied to the transfer film 6 having irregularities, the release agent accumulates in each of the concave portions in the uneven pattern 61, and the release agent is naturally dispersed on the transfer film 6. That is, the release agent can be in the process of laminating the transferred layer 7 It is in a state of being naturally dispersed and substantially uniformly disposed on the surface of the transfer film 6. Thereby, the adhesiveness of the transfer film 6 with respect to the to-be-transferred layer 7 can be controlled to the extent that the protective layer itself is not damaged by an excessive adhesive force when the transfer film is peeled off from the to-be-transferred layer. Thus, since the adhesive force of the transfer film 6 with respect to the to-be-transferred layer 7 can be suitably controlled, the problem which arises when adhesive-bonding-bonding-

Further, when the transfer film 6 is peeled off from the transfer layer 7, the peeling strength of the transfer film 6 with respect to the transfer layer 7 is preferably 1 N/50 mm to 20 N/50 mm in a state before heating and pressurization. If the peel strength value is less than 1 N/50 mm, the transfer film 6 is peeled off from the transferred layer 7 when the mask film 10 is immersed in the chemical liquid, and if the peel strength value is more than 20 N/50 mm, The adhesive force of the release film (transfer film 6) with respect to the transfer layer 7 is too strong, and even when the transfer film 6 is peeled off, the transfer layer 7 may be peeled off together to cause the protective layer to be broken. Further, after the hot pressing is performed to bond the mask film to the printed wiring board, the peeling strength of the transfer film 6 with respect to the transfer layer 7 is preferably 0.2 N/50 mm to 3.0 N/50 mm, and more preferably 0.2. N/50mm-1.0N/50mm. If the peel strength value is less than 0.2 N/50 mm, the transfer film 6 may be naturally peeled off from the transferred layer 7 after hot pressing, and on the other hand, if the peel strength value is more than 3 N/50 mm, it may be made by a person or The device deteriorates operability when the transfer film is peeled off from the transfer layer.

Further, in the present embodiment, the transfer film 6 and the transferred layer 7 are laminated with the release agent layer 6b interposed therebetween, but the present invention is not limited thereto, and may be separated from each other. The type of resin may be laminated or may be laminated without a release agent. If the above two are structures which are laminated without a release resin or a release agent, a release agent may be added thereto. The material forms either outer resin layer.

Here, the peeling strength of the transfer film 6 with respect to the transfer layer 7 in the state before heating and pressurization was measured as follows. Specifically, as shown in FIG. 7, a double-sided tape is attached to the surface of the conductive adhesive layer 8a of the mask film 10 before hot pressing (before heating and pressurization), and one side of the double-sided tape is attached. The mask film 10 was fixed by being attached to a base of a testing machine (PFT-50S peel strength tester manufactured by PALMEK). Then, the end portion of the transfer film 6 of the mask film 10 was placed on a chuck (not shown) of the testing machine, and the peeling strength of the transfer film 6 with respect to the transferred layer 7 was measured. Here, as shown in Fig. 7, as the peeling condition, the peeling angle was set to 170, and the peeling speed of the transfer film 6 by the chuck was set to 1000 mm/min. Further, five tests were carried out, and the maximum value and the minimum value of the peel strength values obtained each time were calculated as the values of the peel strength.

(Mask flexible printed wiring board 100)

FIG. 3 is an explanatory view showing a state in which the mask film 10 is placed on the base film 5 and then heated and pressurized in the layer direction by a press or the like. The base film 5 is configured to include a base film 2, a printed circuit 3, and an insulating film 4. The printed circuit 3 is composed of a signal circuit 3a and a ground circuit 3b and formed on the base film 2, and the printed circuit 3 is removed from the ground circuit 3b. At least a portion (non-insulating portion) 3c is covered by the insulating film 4.

Here, the base film 2 and the printed circuit 3 may be bonded together by a binder, or may be bonded to a so-called non-adhesive type copper clad laminate without using a binder. Further, the insulating film 4 may be bonded to the flexible insulating film by using a binder, or may be formed by a series of methods such as application, drying, exposure, development, and heat treatment of the photosensitive insulating resin. Further, the base film 5 can be implemented by appropriately selecting a single-sided FPC having a printed circuit on one side of the base film, and a double-sided FPC having a printed circuit on both sides of the base film, FPC (flexible printed wiring board) multi-layered FPC with multiple layers, "multi-layer component mounting portion and cable portion" (Japanese registered trademark), a material constituting the multilayer portion is a rigid flexible substrate of a hard material, or a TAB tape for a tape carrier package.

The mask film 10 has a transfer film 6 and a mask film body 9. The mask film main body 9 has a transfer layer 7 and a binder layer 8a, and the transfer layer 7 is formed by coating on the transfer film 6, and the adhesive layer 8a is provided on the transferred layer 7 via the metal layer 8b. The surface on the opposite side to the surface on which the transfer film 6 is in contact. Here, the adhesive layer 8a and the metal layer 8b made of a conductive adhesive form the electromagnetic wave mask layer 8. In the electromagnetic wave mask layer 8, when the adhesive layer 8a softened by heating is pressurized, the adhesive flows into the insulating removal portion 4a as indicated by the arrow, and is electrically connected to the ground circuit (refer to Fig. 3). As described above, in the present embodiment, the ground circuit 3b of the base film 5 (printed wiring board) is connected to the conductive adhesive layer 8a. However, the present invention is not limited thereto, and the conductive adhesive layer does not necessarily need to be printed with the printed wiring board. Ground connection.

When the above-described deformation of the adhesive layer 8a occurs, as shown in Fig. 4, the metal layer 8b is biased in the direction in which the adhesive layer 8a is deformed, thereby causing the metal layer 8b to be deformed. Then, the transfer layer 7 and the outer resin layer 63 in which the uneven pattern 61 is formed, the inner resin layer 62, and the outer resin layer 63 of the outermost layer are biased in the same direction to be deformed. At this time, since the transferred layer 7 and the outer resin layer 63 are bonded to each other, the force generated by the deformation of the transferred layer 7 is favorably transmitted to the outer resin layer 63. In addition, since the outer resin layer 63 is composed of polyparaphenylene The butylene glycol dicarboxylate is formed, and the inner resin layer 62 is formed of polyethylene terephthalate. Therefore, the outer resin layer 63 can exhibit good followability with respect to the deformation of the transferred layer 7. Thereby, since the transfer film 6 and the entire laminated body including the transfer layer 7 can follow the deformation of the adhesive layer 8a, deformation of the adhesive layer 8a in the direction in which the adhesive removal portion 4a flows is not hindered. In other words, by using the transfer film 6 and the transferred layer 7, it is possible to prevent the void from being formed in the insulating removal portion 4a and the adhesive layer 8a, and it is possible to improve the embedding property.

Further, after the adhesive layer 8a and the non-insulating portion 3c of the grounding circuit 3b and the insulating film 4 are sufficiently bonded to form a mask flexible printed wiring board, when the transfer film 6 of the mask film 10 and the release agent layer 6b are formed (reference drawing) 1) When peeling off together, the mask FPC101 in which the transfer pattern 71 is provided on the surface of the transfer layer 7 shown in Fig. 5 is obtained.

The material constituting the base film 2 and the insulating film 4 may, for example, be polyester, polybenzimidazole, polyimide, polyamidamine, polyetherimine, polyphenylene sulfide (PPS), or ring. Resin such as oxygen resin. When heat resistance is not required, an inexpensive polyester film is preferably used, and when flame resistance is required, a polyphenylene sulfide film can be used, and when heat resistance is further required, a polyimide film is preferably used.

The adhesive layer 8a is made of a thermoplastic resin such as polystyrene, vinyl acetate, polyester, polyethylene, polypropylene, polyamide, rubber or acryl, or phenol or epoxy as the adhesive resin. It is composed of a thermosetting resin such as a urethane, a melamine or an alkyd. Further, a conductive adhesive which is electrically conductive by mixing a conductive filler such as metal or carbon into these adhesive resins may be used. Thus, the ground circuit 3b and the metal layer 8b can be reliably electrically connected by using a conductive adhesive. Further, as the conductive adhesive, an anisotropic conductive adhesive which reduces the content of the conductive filler can also be used. In this way, as When an anisotropic conductive adhesive is used as the conductive adhesive, a thin film is more easily formed than an isotropic conductive adhesive, and since the conductive filler content is small, a mask film excellent in flexibility can be obtained. Further, an isotropic conductive adhesive may be used as the conductive adhesive. As described above, when an isotropic conductive adhesive is used as the conductive adhesive, only the conductive adhesive layer formed of the isotropic conductive adhesive is provided so that the ground connection to the ground circuit 3b or the like can be performed, and Electromagnetic wave mask effect. In addition, when there is no particular requirement for heat resistance, it is preferable to use a polyester-based thermoplastic resin which is not restricted by storage conditions and the like, and when heat resistance is required or more excellent flexibility is required, it is preferable to use the electromagnetic wave mask layer 8 to be reliably used. Highly epoxy-based thermosetting resin. Further, as the adhesive layer 8a, a conductive adhesive having adhesiveness at normal temperature can also be used.

Further, in the above-described embodiment, the metal layer 8b and the adhesive layer 8a are used as the electromagnetic wave mask layer 8. However, when the isotropic conductive adhesive is used as the adhesive layer 8a as described above, the metal may be omitted. The structure of layer 8b.

As the conductive filler, carbon, silver, copper, nickel, solder, aluminum, silver-coated copper-plated copper on copper powder, and a metal-plated filler on a resin ball or a glass ball or the like, or a mixture of these fillers may be used. . Since the price of silver is high, copper is insufficient in heat resistance reliability, aluminum is insufficient in moisture resistance reliability, and it is difficult to obtain sufficient conductivity of solder, it is preferable to use a relatively inexpensive and excellent conductivity and high reliability. Silver-clad copper filler or nickel.

The mixing ratio of the conductive filler such as a metal filler to the adhesive resin is also affected by the shape of the filler. When the silver-coated copper filler is used, it is preferable to use 10 to 400 parts by weight of the silver-coated copper filler with respect to 100 parts by weight of the adhesive resin. ,more It is preferred to use 20 to 150 parts by weight of a silver-coated copper filler. When it exceeds 400 parts by weight, the adhesion to the ground circuit (copper foil) 3b is lowered, and the flexibility of the mask FPC 101 is deteriorated. In addition, when it is less than 10 parts by weight, the electrical conductivity is remarkably lowered. Further, when a nickel filler is used, it is preferred to use 40 to 400 parts by weight of the nickel filler, and more preferably 100 to 350 parts by weight of the nickel filler, relative to 100 parts by weight of the binder resin. When it exceeds 400 parts by weight, the adhesion to the ground circuit (copper foil) 3b is lowered, and the flexibility of the mask FPC 101 is deteriorated. In addition, when it is less than 40 parts by weight, the conductivity is remarkably lowered. The shape of the conductive filler such as a metal filler may be any of a spherical shape, a needle shape, a fiber shape, a flake shape, or a dendritic shape.

As described above, when a conductive filler such as a metal filler is mixed, only the thickness of these fillers is increased, that is, about 20 ± 5 μm. Further, when the conductive filler is not mixed, the thickness of the adhesive layer 8a is from 1 μm to 10 μm. Therefore, the thickness of the electromagnetic wave mask layer 8 can be reduced, and the thin mask FPC101 can be formed.

Examples of the metal material forming the metal layer 8b include aluminum, copper, silver, gold, and the like. It is also possible to appropriately select the metal material according to the required mask characteristics, but since copper has a problem of being easily oxidized when it comes into contact with air, gold is expensive, and it is preferable to use inexpensive aluminum or highly reliable silver. The film thickness is appropriately selected in accordance with the required mask characteristics and flexibility, but it is generally preferable to set the film thickness to be 0.01 μm to 1.0 μm. When the film thickness is less than 0.01 μm, the mask effect is insufficient, and conversely, when the film thickness exceeds 1.0 μm, the flexibility is deteriorated. The method of forming the metal layer 8b includes vacuum deposition, sputtering, CVD, MO (metal organic), plating, and the like. However, in consideration of mass productivity, vacuum deposition is preferably used, and an inexpensive and stable metal film can be obtained. Further, the metal layer is not limited to the metal film, and a metal foil may also be used. The lower limit of the thickness of the metal foil when the metal foil is used is preferably 2 μm, more preferably 6 μm. Further, the upper limit of the thickness of the metal foil is preferably 18 μm, and more preferably 12 μm.

Although the embodiments of the present invention have been described above, the specific examples are merely exemplified, and the present invention is not particularly limited, and the specific configuration may be appropriately modified. Further, the actions and effects described in the embodiments of the invention are merely illustrative of the most appropriate actions and effects obtained by the present invention, and the actions and effects obtained by the present invention are not limited to those described in the embodiments of the present invention.

[Examples]

Next, the present invention will be specifically described using examples and comparative examples of the laminated film of the present embodiment.

As a configuration using the configuration shown in FIG. 1, that is, the mask film 10 having the transfer film 6 and the mask film main body 9, the mask film main body 9 has a turn-over laminated on one of the outer resin layers 63. Print layer 7.

The transfer film 6 used in the examples was a film processed by an extrusion lamination method, and the layer thickness thereof was 57 ± 3 μm in total. Further, the arithmetic mean roughness Ra of the uneven pattern 61 was 0.35 μm. Further, the tensile strength TD (lateral direction) or MD (vertical direction) of the transfer film 6 is 220 to 225 MPa. Further, the shrinkage test results of the transfer film 6 after heat treatment at 170 ° C for 10 minutes were as follows: TD was 0%, and MD was 0.7%.

Specifically, a method of producing the transfer film 6 used in the examples will be described. The outer resin layers 63 and 63 are made of PBT resin manufactured by WinTech Polymer Co., Ltd. (trade name: " (Japanese registered trademark)"). The inner resin layer 62 is a PET resin having a layer thickness of 25 μm manufactured by Unitika Co., Ltd. (trade name: " (Japanese registered trademark)").

First, as shown in FIG. 2, the biaxially stretched PET film wound up on the inner resin layer roll 21 is guided to the transfer film roll 25. On the other hand, the PET resin was introduced into any of the film extruders 22 and 22, and was melt-kneaded in an extruder having a set temperature of 235 ± 5 °C. Then, the PBT resin was extruded from the T stage (flat extrusion port) of the film extruders 22, 22 (effective extrusion width: 1300 mm) onto both sides of the above PET resin, and the resin thickness was about 16 ± 3 μm.

Thus, the transfer film 6 is received by the rotating embossing roll 23 and the casting roll 24 to form a film by extruding the PBT resin onto both faces of the PET resin. At this time, the temperatures of the embossing roller 23 and the casting roller 24 were adjusted to 130 ± 3 °C. Further, the embossing roll 23 and the casting roll 24 were set to have a roll diameter of 500 mm and a peripheral speed of 20 m/min. The transfer film 6 after the film formation was gradually cooled at a rate of 10 ° C / sec and converted from amorphous to crystalline, and then taken up by the transfer film roll 25 .

The transfer film 6 manufactured as described above was formed into a material having a width of 1200 mm as a transfer film of the example.

Further, in the comparative example, a PET film having a layer thickness of 50 μm after blasting by a width of 1200 mm was used as a transfer film.

As shown in FIG. 6, the transfer film 206 of the above-described examples and comparative examples was laminated with a release film layer (not shown) of about 0.6 μm to form a mask film 210, which was used to produce a mask film 210. The main body 209 is composed of a transfer layer 207 having a layer thickness of 5 to 7 μm, a metal thin film having a thickness of about 0.1 μm, that is, a metal layer 208b, and a conductive adhesive layer 208a having a layer thickness of about 16 μm.

Further, the transferred layer 207 is provided with a transparent resin layer on the side where the transfer pattern is transferred by the transfer film 206, and a two-layer structure in which a black resin layer is laminated on the transparent resin layer is used.

(Evaluation of Transfer Film of Example)

In the present manufacturing process, the transfer film of the example did not cause curling and shrinkage, and thus the handleability was good. In addition, since the uneven pattern (transparent processing) is formed on one surface (outer resin layer) of the transfer film, the slidability of the transfer film is good, and the completion state of the coating can be improved.

(evaluation of embeddedness)

As shown in FIG. 6, the base film 205 has a structure in which two copper foil printed circuits 203 having a layer thickness of 55 μm are laminated on a polyimide film base film 202 having a layer thickness of 25 μm at a sufficient interval, and each printing is performed. On the circuit 203, an insulating film 204 made of polyimide having a layer thickness of 50 μm is laminated. In addition, the sufficient interval means that the conductive adhesive layer 208a does not reach the printed circuit 203 even when the conductive adhesive layer 208a flows into the gap 213 when the mask film 210 is hot pressed. . Further, each of the insulating films 204 is formed with an insulating removal portion (through hole) 204a to expose a part of each of the printed circuits 203. When the diameter of the insulating removal portion 204a is 0.5 mm, 0.8 mm, and 1.0 mm, the mask films of the examples and the comparative examples are subjected to hot pressing, and the resistance values between the two printed circuits 203 are measured 3 The results are shown in Table 2.

As shown in Table 2, in the examples, regardless of the value of the diameter of the insulating removal portion 204a, it is lower than the connection resistance value of the comparative example, and the printed circuits are easily turned on. In other words, it is understood that the conductive adhesive layer 208a is more likely to flow into the insulating removal portion 204a than in the comparative example, and reaches the printed circuit 203, so that the resistance value is lowered, and good embedding property can be obtained.

(Evaluation of surface roughness)

The mask film 210 of the examples and comparative examples shown in Fig. 6 was used. Rectangular test pieces each having a length of 200 mm and a width of 50 mm were used.

The surface roughness (Ra (μm)) in the examples was measured using an ultra-depth shape measuring microscope VX-8550 (KEYENCE). The measurement conditions were based on JIS B0601 (1994), and the 20-fold objective lens had a measurement pitch of 0.2 μm in the thickness direction.

Specifically, after the mask film 210 is wound up on the reel, five tests are selected from the three portions (starting portion, 1000 m (middle portion), and 2000 m (final portion)) in the flow direction (MD direction). Sheet (n=5) (total of 15 test pieces), the surface roughness (Ra) in the examples was measured using an ultra-depth shape measuring microscope VX-8550 (KEYENCE). The average value, the maximum value, and the minimum value of the five test pieces in each of the above-described flow directions were obtained as measured values. Further, the difference between the maximum value and the minimum value of the above 15 test pieces was taken as the deviation of the arithmetic mean roughness. The results are shown in Table 3.

The deviation of the arithmetic mean roughness (0.38 μm, 0.31 μm, 0.35 μm) of the examples was considerably smaller than that of the comparative examples (0.85 μm, 0.73 μm, 0.73 μm). The reason for this is that in the processing using the embossing roll, a concave-convex pattern is formed on the roll, and the uneven pattern is repeatedly formed on the outer resin layer 63 of the transfer film 6, so that a certain uneven pattern can be realized. Therefore, the embodiment can stabilize the adhesion force and the peeling force of the respective bonding surfaces between the transfer film 6 and the transferred layer 7 as compared with the comparative example using the sandblasting.

(evaluation of peelability before heating)

The peeling strength of the transfer film 6 with respect to the layer to be transferred 7 in the state before hot pressing was measured in the following manner. Specifically, a test piece having a width of 50 mm and a length of 200 mm was cut out from the mask film 210 of the comparative example and the example shown in Fig. 6, and the test piece was used as the mask film 10, as shown in Fig. 7, in the mask film. A double-sided tape was attached to the surface of the conductive adhesive layer 8a of 10, and one side of the double-sided tape was attached to a base of a testing machine (PFT-50S peel strength tester manufactured by PALMEK) and the mask film 10 was fixed. Then, the end portion of the transfer film 6 of the mask film 10 was placed on a chuck of the testing machine, and the peeling strength of the transfer film 6 with respect to the transferred layer 7 was measured. Here, as shown in Fig. 7, as the peeling condition, the peeling angle was set to 170, and the peeling speed of the transfer film 6 by the chuck was set to 1000 mm/min. Further, five tests were carried out for the comparative examples and the examples, respectively, and the maximum value and the minimum value were calculated for each test. The results are shown in Table 4.

In addition, the evaluation criteria of the peelability are as follows. Specifically, before the hot pressing, it was confirmed that the transfer film was detached when immersed in the chemical liquid (no peeling off: ○, there was falling off: ×). Further, before the hot pressing, it was confirmed whether or not the transfer film 7 was peeled off from the transfer layer 7 and was damaged (no damage: ○, damage: ×). and, After the hot pressing, it was confirmed whether or not the transfer film 6 was damaged (no damage: ○, damage: ×). Moreover, the workability at the time of peeling the transfer film 6 from the to-be-transferred layer 7 after hot pressing was confirmed (good: ◎, normal: ○, difference: ×).

(Evaluation of peelability after heating)

On the other hand, the peeling strength of the transfer film 6 with respect to the transferred layer 7 in the state after the hot pressing was measured in the following manner. The surface of the conductive adhesive layer 208a of the mask film 210 of the comparative example and the embodiment was thermocompression bonded to the surface of the polyimide surface of the copper-clad laminate having the surface of the polyimide and the surface of the copper foil using a press. As the thermocompression bonding conditions in the press at this time, the set pressure is preferably 2 to 5 MPa, the temperature is 140 to 180 ° C, and the time is 3 to 60 minutes. In this measurement, 170 ° C was used as the set temperature, and the weight was downloaded at 0.5 MPa for 60 seconds, and then the weight was downloaded at 3 MPa for 180 seconds to perform thermocompression bonding.

Then, a double-sided tape was adhered to the surface of the copper foil of the copper-clad laminate after the thermocompression bonding of the mask film 210, and as shown in FIG. 7, one side of the double-sided tape was attached to a test machine (PFT by PALMEK) The mask film 210 is fixed on the -50S peel strength tester. Thereafter, the peel strength value was calculated in the same manner as the test method described above for the peel strength measurement before punching.

As shown in Table 4, in the state after hot pressing, the maximum value and the minimum value of the examples in the five peeling experiments were 0.88 N/50 mm and 0.29 N/50 mm, respectively, and the maximum value and the minimum value of the comparative examples were respectively 2.94 N/50 mm and 1.37 N/50 mm, the examples showed less variation than the comparative examples. Thereby, after the hot pressing, the operability at the time of peeling a transfer film from a to-be-transferred layer is favorable.

Further, as shown in Table 4, when the peeling forces of the examples and the comparative examples were compared, there was no significant difference between the examples and the comparative examples before the hot pressing (before the hot pressing of the examples: the maximum value was 5.34 N/ 50 mm, the minimum value is 3.78 N/50 mm; before the hot pressing of the comparative example: the maximum value is 5.88 N/50 mm, and the minimum value is 3.92 N/50 mm), but after hot pressing, the peeling of the example is compared with the comparative example. Significantly reduced force After the hot pressing of the example: the maximum value is 0.88 N/50 mm, and the minimum value is 0.29 N/50 mm; after the hot pressing of the comparative example: the maximum value is 2.94 N/50 mm, and the minimum value is 1.37 N/50 mm). Specifically, when focusing on the maximum value of the peeling force, the peeling force of the comparative example after the hot pressing was reduced to about 1/2 of the original value, whereas the example was decreased to about 1/6 of the original. Thereby, before the hot pressing, the transfer force of the transfer film with respect to the transfer layer in the embodiment is high, and it is possible to prevent the transfer film from being peeled off in a usual subsequent step such as the immersion chemical solution, and the adhesive force is remarkably lowered after the hot pressing. The operability at the time of peeling a transfer film can be improved.

1‧‧‧ mask film

6‧‧‧Transfer film

6b‧‧‧ release layer

7‧‧‧Transfer layer

61‧‧‧ concave pattern

61a‧‧‧ convex

61b‧‧‧ recess

62‧‧‧Inner resin layer

63‧‧‧Outer resin layer

71‧‧‧Transfer pattern

71a‧‧‧ top

71b‧‧‧ bottom

Claims (8)

A laminated film comprising: a transfer film having an inner resin layer and an outer resin layer laminated on one surface and the other surface of the inner resin layer, respectively, and formed on an outer surface of at least one of the outer resin layers a concave-convex pattern; and a transfer layer laminated on the outer surface of the transfer film on which the concave-convex pattern is formed, and having a transfer pattern formed by the concave-convex pattern, wherein the inner resin layer is formed by a pair Formed by ethylene phthalate, the outer resin layer is formed of polybutylene terephthalate. The laminated film according to the first aspect of the invention, wherein the unevenness pattern formed on the outer resin layer has an arithmetic mean roughness of 0.2 μm to 2.5 μm. The laminated film according to the second aspect of the invention, wherein the unevenness of the arithmetic mean roughness of the uneven pattern formed on the outer resin layer is 0.50 μm or less. The laminated film according to any one of claims 1 to 3, wherein the transfer film is formed by laminating the outer resin layer on both surfaces of the inner resin layer by an extrusion lamination method, and At least one of the two rolls having irregularities formed on the surface thereof is pressurized. The laminated film according to any one of claims 1 to 3, wherein the transfer layer is the protective layer of a mask film having a conductive adhesive layer, a metal layer, and a protective layer, the metal The layer is laminated on the conductive adhesive layer, and the protective layer is laminated on the metal layer. The laminated film according to any one of claims 1 to 3, wherein the transfer layer is the protective layer in a mask film having a conductive adhesive layer and a protective layer, and the protective layer is laminated. On the above metal layer. A mask printed wiring board characterized in that the mask film according to claim 5 is bonded to a printed wiring board. A mask printed wiring board characterized in that the mask film described in claim 6 is bonded to a printed wiring board.