JP2004133484A - Photosensitive film and method for laminating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive film which sufficiently coats the ruggedness of a substrate without forming bubbles and a method for laminating the same. <P>SOLUTION: The photosensitive film is formed by laminating a flexible support, a photosensitive composition layer, and a protective film having the adhesiveness to the photosensitive composition layer smaller than the adhesiveness of the flexible support to the photosensitive composition layer in this order, in which the cutoff value of the surface roughness of the surface of the protective film being in contact with the photosensitive composition layer is adjusted to 0.08 to 8 mm and the arithmetic mean roughness (Ra) within the measurement range of from 0.4 to 40 mm in evaluation length is adjusted to ≥0.5 μm. The method for laminating the photosensitive film comprises the steps of removing the protective film of the photosensitive film and laminating the photosensitive composition layer under reduced pressure such that the surface having the surface roughness of the photosensitive composition layer comes into contact with the substrate. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a photosensitive film and a method for laminating the same, and more particularly, to a photosensitive film having excellent coatability on an uneven substrate under reduced pressure and a method for laminating the same.

Conventionally, in the printed wiring board industry, in order to prevent solder bridges that are likely to occur at the time of soldering when mounting components on a printed wiring board, and to corrode conductors and to maintain insulation between conductors, conductors such as Forming a protective film on a surface has been performed. As such a permanent protective film, a photosensitive layer is provided on a flexible support such as a polyethylene terephthalate film, and a protective film such as a polyethylene film is provided on the photosensitive layer to temporarily protect the photosensitive layer. Photosensitive film is used. When a protective film is formed using this photosensitive film, heat and pressure are applied in a decompression chamber as described in Patent Document 1 in order to prevent air bubbles from being trapped between conductor patterns on a printed wiring board. An apparatus is used in which the photosensitive layer of the photosensitive film, from which the protective film has been removed, is passed over the printed wiring board so as to cover and embed the conductor. This apparatus is generally called a continuous vacuum laminator because it can simultaneously laminate a printed wiring board and a photosensitive film. On the other hand, for a flexible printed wiring board, a polyimide film provided with an adhesive layer is punched out of a predetermined pattern with a mold or the like to prevent solder bridging, conductor corrosion prevention, and insulation between conductors. Although a protective film is formed by pressing, a photosensitive film called a photosensitive coverlay has been used in response to recent demand for higher definition. In order to laminate this photosensitive coverlay on a flexible printed wiring board, a vacuum laminator generally called a batch type, which is described in Patent Documents 2 and 3 and the like, which has little curl during lamination, is used. . The continuous vacuum laminator removes the protective film of the photosensitive film on the substrate under reduced pressure and laminates the photosensitive layer, while the batch type vacuum laminator removes the protective film of the photosensitive film on the substrate under air. And then placed under reduced pressure to be laminated. For this reason, when using a batch type vacuum laminator, if the tackiness of the photosensitive layer of the photosensitive film and the substrate, especially the conductor of the convex portion, etc. is strong, the atmosphere in the concave portion cannot be removed even under a reduced pressure, resulting in bubbles, The conductor such as the conductor of the convex portion cannot be sufficiently covered, and cannot serve as a protective film. In general, the photosensitive layer of a photosensitive film used for a substrate having irregularities has a high fluidity in order to obtain a good embedding property, so that the tack tends to be strong. Even a photosensitive film intended to form a circuit on a printed wiring board may use a vacuum laminator with a high flow rate in order to embed scratches and the like on the surface of a smooth copper-clad laminate. It becomes tacky, resulting in bubbles remaining inside the scratch.
JP-B-53-31670 Japanese Patent Publication No. 55-13341 JP-A-8-132531

An object of the present invention is to provide a photosensitive film and a method of laminating the same, which eliminate the problems of the prior art and sufficiently cover unevenness of a substrate without bubbles.

The present invention relates to a photosensitive substrate obtained by laminating a flexible support, a photosensitive composition layer, and a protective film having lower adhesion to the photosensitive composition layer than the adhesion of the flexible support to the photosensitive composition layer in this order. In a functional film, the surface roughness of the surface of the protective film that comes into contact with the photosensitive composition layer has a cutoff value of 0.08 to 8 mm and an evaluation length of 0.4 to 40 mm in the measurement range of arithmetic mean roughness ( A photosensitive film having a Ra of 0.5 μm or more.

The present invention also includes removing the protective film of the photosensitive film, removing the protective film of the photosensitive composition layer, and reducing the pressure so that the surface having the surface roughness of the photosensitive composition layer contacts the substrate. And a method for laminating a photosensitive film.

と By using the photosensitive film and the laminating method of the present invention, it is possible to obtain a photosensitive resin layer in which the surface of the substrate having irregularities is sufficiently covered, particularly under reduced pressure, without bubbles.

In general, a photosensitive film has a configuration in which a flexible support, a photosensitive composition layer, and a protective film are laminated in this order, and when laminated on a substrate or the like, the photosensitive composition layer is formed on the substrate surface except for the protective film. The layers are brought into contact with each other, and heated and pressed to be laminated. Then, in order to cover irregularities without involving air bubbles, lamination is generally performed under reduced pressure. In particular, when a batch type vacuum laminator is used, if the flowability of the photosensitive composition layer is increased to bury the unevenness, the adhesive force with the convex portion becomes strong, and the deaeration of the concave portion becomes difficult even under reduced pressure, and sufficient coating is performed. Becomes impossible.

In the present invention, the surface of the photosensitive composition layer on the side in contact with the substrate surface to be laminated is given a certain range of surface roughness, and laminated under reduced pressure to sufficiently cover the irregularities of the substrate without bubbles. Can be. The surface roughness given to this photosensitive composition layer must be eliminated by pressing during lamination in order to sufficiently cover the unevenness of the substrate, but if the surface roughness is not maintained before lamination. No. Therefore, the photosensitive composition layer needs to have a certain fluidity. Therefore, by using a protective film having a surface roughness on the side facing the photosensitive composition layer, a primary surface roughness is given to the photosensitive composition layer having fluidity, thereby having fluidity. The photosensitive composition layer follows the surface roughness of the protective film to obtain the required surface roughness at the time of lamination, and the surface roughness disappears due to the pressure at the time of lamination and sufficiently covers the unevenness of the substrate without bubbles. it can. However, the protective film having this surface roughness must have lower adhesion to the photosensitive composition layer than the flexible support.

The surface roughness of this protective film is represented by the arithmetic average roughness (Ra) defined in Japanese Industrial Standard JIS B0601-1994, with a cutoff value of 0.08 to 8 mm and an evaluation length of 0.4 to 40 mm. The arithmetic average roughness (Ra) needs to be 0.5 μm or more in the measurement range. The arithmetic average roughness (Ra) is preferably in the range of 0.1 to 50% of the thickness of the photosensitive composition layer, and more preferably 1 to 20%. The ten-point average roughness (Rz) defined in Japanese Industrial Standard JIS B0601-1994 is 0.5 μm in a measurement range where the reference length is 0.08 to 8 mm and the evaluation length is 0.4 to 40 mm. The thickness is preferably in the range of 0.1% to 50% of the thickness of the photosensitive composition layer, more preferably 1% to 20%. Further, the photosensitive composition layer has a maximum height (Ry) defined in Japanese Industrial Standard JIS B0601-1994 in a measurement range of a reference length of 0.08 to 8 mm and an evaluation length of 0.4 to 40 mm. Is preferably not more than twice the layer thickness.

Here, the cutoff value is a cutoff value of a roughness curve defined in Japanese Industrial Standard JIS B0601-1994, and indicates a wavelength corresponding to a frequency at which the gain of the phase-compensated high-pass filter becomes 50%. Things.

は Surface roughness can be measured generally using a stylus-type surface roughness meter based on Japanese Industrial Standard JIS B0601-1994, and the tip radius of the stylus used for measurement is preferably 2 μm.

If the surface roughness of the photosensitive composition layer is less than 0.5 μm in arithmetic mean roughness (Ra) in a measurement range of cutoff value of 0.08 to 8 mm and evaluation length of 0.4 to 40 mm, lamination on a substrate Sometimes it becomes easy to entrap air bubbles. If the thickness of the photosensitive composition layer is less than 0.1%, bubbles tend to be easily entrained during lamination on the substrate, and if it exceeds 50%, it is difficult to sufficiently cover the unevenness of the substrate. Tend.

The photosensitive composition layer of the photosensitive film used enhances the conformability to the unevenness of the substrate to be laminated, enhances the embedding property, and also temporarily retains the surface roughness to sufficiently cover and embed the unevenness of the substrate. It is necessary to have fluidity. The fluidity is such that when a static load of 0.25 kg / mm ² is applied to a photosensitive composition layer having a thickness of 2 mm at a temperature of 30 ° C., the time elapses from 10 seconds to 600 seconds after the load is applied. Is preferably in the range of 50 to 800 μm. More preferably, the thickness variation is in the range of 100 to 500 μm.

(4) When the thickness change is less than 50 μm, not only does it become difficult for the photosensitive composition layer to follow the surface roughness of the protective film, but also it tends to be difficult to sufficiently cover or embed the irregularities on the substrate. If the thickness change exceeds 800 μm, it becomes difficult to temporarily maintain the surface roughness of the photosensitive composition layer after removing the protective film, and the photosensitive composition layer on the surface in contact with the substrate Surface roughness disappears, the effect of surface roughness cannot be obtained, and it tends to be difficult to sufficiently cover or embed irregularities on the substrate.

加熱 When laminating the protective film having the surface roughness on the surface of the photosensitive composition layer, heating and pressing may be performed within a range where the characteristics of the photosensitive composition do not change.

公 知 Well-known flexible supports, photosensitive composition layers and protective films of the photosensitive film used in the present invention can be used. The thickness of the flexible support is preferably from 12 to 25 μm, the thickness of the photosensitive composition layer is preferably from 5 to 30 μm, and the thickness of the protective film is preferably from 15 to 50 μm.

As the flexible support and protective film of the photosensitive film used in the present invention, for example, polyethylene, polyethylene terephthalate film, polyimide film, polyamide film, polypropylene film, polymer film such as polystyrene film is used, A polyethylene terephthalate film is preferably used as the support, and a polyethylene film is preferably used as the protective film.

保護 The protective film having a surface roughness can be obtained, for example, by passing a stretched polyethylene film between a metal roll and a rubber roll on the surface of which a pattern called satin is processed. The film thus obtained is called a satin finished film or an embossed film.

で は Also, in another method, fine particles can be uniformly dispersed in the film to obtain a film for a protective film having a surface roughness, but the method for obtaining a protective film having a surface roughness is not limited to these methods.

感光 The photosensitive composition layer of the photosensitive film used in the present invention comprises, for example, (a) a thermoplastic polymer, (b) an unsaturated group-containing monomer, and (c) a photopolymerization initiator.

(A) Examples of the thermoplastic polymer include vinyl copolymers. Examples of the copolymer monomer used include acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and methacrylic acid. 2-ethylhexyl, lauryl methacrylate, methyl acrylate, ethyl acrylate, styrene, α-methylstyrene, vinyltoluene, N-vinylpyrrolidone, acrylamide, acrylonitrile, methacrylonitrile, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, etc. No. Also, a half ester of a styrene / maleic acid copolymer may be used.

The weight average molecular weight of the thermoplastic polymer (measured in terms of standard polystyrene using GPC) is preferably from 20,000 to 300,000, and more preferably from 50,000 to 150,000.

As the unsaturated group-containing monomer of the component (b), for example, a compound obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol (polyethylene glycol diacrylate (where the number of ethylene groups is 2 to 14) ), Trimethylolpropane diacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethanetetraacrylate, polypropylene glycol diacrylate (having 2 to 14 propylene groups), dipentaerythritol pentaacrylate , Dipentaerythritol hexaacrylate, etc.), bisphenol polyoxyethylene diacrylate (bisphenol dioxyethylene diacrylate, bisphenol trioxyethylene diacrylate, bisphene) A compound obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (trimethylolpropane triglycidyl ether triacrylate, bisphenol diglycidyl ether acrylate, etc.), , 2-bis (4-methacryloxypolyethoxyphenyl) propane, esterified product of a polycarboxylic acid (such as phthalic anhydride) with a compound having a hydroxyl group and an ethylenically unsaturated group (such as β-hydroxyethyl acrylate), acrylic Alkyl esters of acids (methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.), obtained by reacting trimethylhexamethylene diisocyanate with a dihydric alcohol and a dihydric acrylic monoester. Urethanedia Acrylate compounds and methacrylates corresponding thereto.

The compounding amount of the component (a) in the present invention is preferably 40 to 80 parts by weight (so that the total amount of the component (a), the component (b) and the component (c) is 100 parts by weight). , More preferably 50 to 70 parts by weight, particularly preferably 55 to 65 parts by weight.

Examples of the photopolymerization initiator used as the component (c) in the present invention include aromatic ketones (benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N, N'-tetraethyl Benzoin ethers such as -4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-ethylanthraquinone, phenanthrenequinone and benzoin (benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether) , Methylbenzoin, ethylbenzoin, etc.), benzyl derivatives (benzyldimethylketal, etc.), 2,4,5-triarylimidazole dimer (2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, -(O-chlorophenyl -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenyl Imidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4 -Dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, etc., acridine derivatives (9-phenylacridine, 1,7-bis (9,9'-acridinyl) heptane and the like), ethyl dimethylaminobenzoate, diethylthioxanthone and the like. These are used alone or in combination of two or more.

The amount of the component (c) in the present invention is preferably 0.10 to 20 parts by weight, and more preferably 0.15 to 15 parts by weight, based on 100 parts by weight of the total of the components (a) and (b). More preferably, it is particularly preferably 0.20 to 10 parts by weight.

The photosensitive composition layer of the photosensitive film used in the present invention includes a thermosetting component such as hexamethoxymethylmelamine, a dye, a pigment, a plasticizer, a stabilizer, and 2-amino-5-mercapto-1,3,3. An adhesion improver such as 4-thiadiazole, a filler, and the like are added as necessary.

The photosensitive film used in the present invention includes, for example, a photosensitive composition comprising (a) a thermoplastic polymer, (b) an unsaturated group-containing monomer, and (c) a photopolymerization initiator. After a solution uniformly dissolved in a solvent or the like is uniformly applied on a flexible support, the solvent is removed by heating and / or blowing with hot air to obtain a dry film. The thus obtained photosensitive film composed of two layers of the flexible support and the photosensitive composition layer is stored as it is or by laminating a protective film on the photosensitive composition layer and winding it into a roll. Is done.

The flexible support used in the present invention, the photosensitive composition layer, the photosensitive film comprising a protective film having a surface roughness, after removing the protective film, the photosensitive composition layer to which the surface roughness was transferred. The substrate is laminated and adhered by heating and pressing, but it is effective to perform the process under reduced pressure in order to sufficiently fill and cover the unevenness of the substrate. The pressure, temperature and time at this time may be within a range where a film thickness capable of maintaining the characteristics of the photosensitive composition layer can be obtained.

(4) The photosensitive film thus laminated is then imagewise exposed to active light using a negative film or a positive film. At this time, the light may be exposed except for the flexible support on the photosensitive composition layer. After the exposure, if there is a flexible support on the photosensitive composition layer, except for that, using an organic solvent or an aqueous alkali solution, for example, spraying, rocking immersion, brushing, scrubbing and the like by known methods such as The unexposed or exposed portions are removed and development is performed. Thereafter, in order to enhance the characteristics, the film is further cured by irradiation with light.

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
Example 1

A solution 6 having a composition shown in Table 1 was uniformly applied on a polyethylene terephthalate film 12 having a thickness of 25 μm using the apparatus shown in FIG. After drying for 5 minutes to remove the solvent, the thickness of the photosensitive composition layer was adjusted to 25 μm. In FIG. 1, 1 is a polyethylene terephthalate film feeding roll, 2 is a feed roll, 3 is a backing roll, 4 is a doctor roll, 9 and 10 are rolls, 5 is a knife, 6 is a photosensitive composition solution, and 7 is a dryer. Reference numeral 8 denotes a polyethylene film feeding roll, and reference numeral 11 denotes a photosensitive film winding roll.

When a photosensitive load of 0.25 kg / mm ² was applied to a sample in which the photosensitive composition layers were overlapped and the layer thickness was 2 mm, a film was formed after 10 seconds to 600 seconds after the load was applied. The thickness change amount was 288 μm. Next, using a device shown in FIG. 1, a polyethylene film 13 (protective film) was further laminated on the photosensitive composition layer to obtain a photosensitive film. The surface roughness of the protective film used at this time was measured using a surface roughness measuring device, Surfcoder SE-30D (manufactured by Kosaka Laboratory Co., Ltd.), at a probe tip radius of 2 μm and a scanning speed of 0.1 mm / sec. As a result, the arithmetic average roughness (Ra) was 1.2 μm (4.8% of the photosensitive composition layer) in the measurement range where the cutoff value was 0.08 mm and the evaluation length was 2.5 mm. The maximum height (Ry) was 10.5 μm (21% of the photosensitive composition layer).

Next, using a device shown in FIG. 2, a printed wiring board having a copper circuit having a thickness of 18 μm formed on both surfaces thereof is placed on the photosensitive composition layer from which the protective film of the photosensitive film has been removed, and then pressurized and heated. After sending to a vacuum chamber and contacting the photosensitive composition layer except the protective film of the photosensitive film with the upper surface of the printed wiring board, heating the chamber to 100 ° C. while evacuating the chamber to 1 Torr; The layers were laminated while maintaining a pressure of 0.5 kg / cm ² for 3 minutes. Thereafter, the chamber was released, the printed wiring board on which the photosensitive film was laminated was taken out, and the presence or absence of air bubbles on the circuits and between the circuits was visually observed and observed with a microscope of 50 times. In FIG. 2, 14 is a substrate, 15 and 16 are pressurized, heated, and vacuum chambers, 17 is a fixed film, 18 is a pressurized film, 19 is a vacuum unit, 20 is an air pressurizing unit, and 21 and 22 are photosensitive. Film feed rolls, 23 and 24 are protective film take-up rolls, and 25 and 26 are photosensitive films.

Next, the printed wiring board on which the photosensitive film was laminated was exposed to 80 mJ / cm ² through a negative mask using an ultra-high pressure mercury lamp, and further sprayed using a 1% by weight aqueous sodium carbonate solution at a spray pressure of 1.0 kg / cm ^2. The development was carried out at a liquid temperature of 30 ° C. Thereafter, ultraviolet rays of 1 J / cm ² were irradiated with a high-pressure mercury lamp, and further heated at 150 ° C./60 minutes to form a cured film. The printed wiring board on which the cured film was formed was immersed in a solder bath at 260 ° C. for 10 seconds, and the appearance was visually observed and observed with a 50 × microscope. Table 2 shows the results.

Example 2
The surface roughness is 3.4 μm in arithmetic average roughness (Ra) (13.6% of the thickness of the photosensitive composition layer), and 22.8 μm in maximum height (Ry) (45.6% of the photosensitive composition layer). ) Was performed in the same manner as in Example 1 except that the protective film was used, and the presence or absence of air bubbles and the appearance after solder immersion were visually observed and observed with a microscope of 50 times. Table 2 shows the results.

Example 3
The surface roughness is 4.5 μm in arithmetic average roughness (Ra) (18.0% of the thickness of the photosensitive composition layer), and 27.5 μm in maximum height (Ry) (55% of the photosensitive composition layer). The same procedure as in Example 1 was carried out except that the protective film was used, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

Example 4
A photosensitive film in which the fluidity of the photosensitive composition layer was 312 μm except that the layer thickness of the photosensitive composition layer was 50 μm and a printed circuit board having a copper circuit thickness of 35 μm was used. Got. This photosensitive film was laminated on a printed wiring board in the same manner as in Example 1, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

Example 5
The surface roughness was 9.8 μm in arithmetic average roughness (Ra) (19.6% of the thickness of the photosensitive composition layer), and 70.1 μm in maximum height (Ry) (140.2 in the photosensitive composition layer). %) Except that the protective film was used, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

Comparative Example 1
The surface roughness is 0.1 μm in arithmetic average roughness (Ra) (0.4% of the thickness of the photosensitive composition layer), and 1.3 μm in maximum height (Ry) (2.6 in the photosensitive composition layer). %), Except that the protective film was used, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

Example 6
The same procedure as in Example 4 was carried out except that the flowability was changed to 205 μm by changing the drying time after coating the photosensitive film, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

Example 7
A photosensitive film was produced in the same manner as in Example 1 except that the blending amount of 2,2-bis [4- (methacryloxy.polyethoxy) phenyl] propane in Table 1 was changed to 25 parts by weight. At this time, the protective film bonding roll of FIG. 2 was heated to 70 ° C. to bond the protective film. The fluidity at this time was 114 μm. Thereafter, the same procedure as in Example 4 was carried out, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

Example 8
The same procedure as in Example 4 was carried out except that the flowability was changed to 520 μm by changing the drying time after coating the photosensitive film, and the presence or absence of air bubbles and the appearance after solder immersion were observed visually and with a microscope of 50 times. Table 2 shows the results.

As is clear from Table 2, when the photosensitive film and the laminating method of the present invention are used, the uneven substrate can be sufficiently covered without bubbles.

The protective film having the specific surface roughness used above is commercially available, and is manufactured by passing the film between a metal roll and a rubber roll whose surfaces are treated with sandblast. At this time, a protective film having a different surface roughness can be obtained by adjusting the particle size and the spraying time of the sand in the sandblasting treatment to change the unevenness of the roll surface.

1 is a schematic diagram of a photosensitive film manufacturing apparatus used in Examples. The schematic diagram of the lamination apparatus used in the Example.

Explanation of reference numerals

REFERENCE SIGNS LIST 1 Polyethylene terephthalate film pay-out roll 2 Feed roll 3 Backing roll 4 Doctor roll 5 Knife 6 Solution of photosensitive composition 7 Dryer 8 Polyethylene film pay-out roll 9, 10 Roll 11 Photosensitive film take-up roll 12 Polyethylene terephthalate film 13 Polyethylene film 14 Substrates 15, 16 Pressurizing / heating / vacuum chamber 17 Fixing film 18 Pressurizing film 19 Vacuum evacuation unit 20 Air pressurization unit 21, 22 Photosensitive film feed roll 23, 24 Protective film take-up roll 25, 26 Photosensitive film

Claims (4)

Flexible support, photosensitive composition layer and a photosensitive film in which the adhesiveness to the photosensitive composition layer is laminated in this order with a protective film having a smaller adhesion than the adhesiveness to the photosensitive composition layer of the flexible support, The surface roughness of the surface of the protective film that comes into contact with the photosensitive composition layer has an arithmetic mean roughness (Ra) of 0 to 8 mm in cutoff value and 0.4 mm to 40 mm in evaluation range. A photosensitive film having a thickness of 5 μm or more. The photosensitive film according to claim 1, wherein the arithmetic average roughness (Ra) of the protective film is 0.1 to 50% of the thickness of the photosensitive composition layer. When a static load of 0.25 kg / mm ² is applied to the photosensitive composition layer having a layer thickness of 2 mm at a temperature of 30 ° C., from 10 seconds to 600 seconds after the load is applied. The photosensitive film according to claim 1, wherein the photosensitive film has a fluidity in a range of 50 to 800 μm in thickness change with time. 4. The photosensitive film according to claim 1, wherein the protective film of the photosensitive film according to claim 1, 2 or 3 is removed, and the photosensitive composition layer is laminated under reduced pressure such that a surface having a surface roughness of the photosensitive composition layer is in contact with the substrate. Film lamination method.

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