JPS5997135A - Image forming material - Google Patents

Abstract

PURPOSE:To obtain an image forming material giving an image of high quality by forming a photosensitive layer having a specified composition on a transparent support film. CONSTITUTION:A photosensitive layer consisting of 100pts.wt. resin binder, 50-200pts.wt. photopolymerizable monomer which is liq. at ordinary temp., and 0.1-10pts.wt. photopolymn. initiator is formed on a transparent support film. The principal component of the resin binder is a synthetic resin contg. a high mol.wt. part with >=30,000 number average mol.wt. and a low mol.wt. part with <=10,000 number average mol.wt. and having >=3.5 value of weight average mol.wt./number average mol.wt. (Mw/Mn). The resulting resist image on copper foil is a nonviscous hard film with high clearness, and it is not simply stripped from the foil because of the high adhesive strength.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention makes it possible to form an image on an image-forming material, particularly by peeling off a transparent film covering an exposed photosensitive layer after exposure, that is, peeling development is possible. The present invention relates to a material for forming external images.

2. Description of the Related Art Image-forming materials have been known which are comprised of a transparent support film and a layer of a photopolymerizable composition formed by coating or the like on the film. Such an image-forming material can be used, for example, by bringing the photopolymerizable layer into contact with the surface of a substrate on which an image is to be drawn, and adhering the photopolymerizable layer tightly by thermal fusion or the like, and then using active light transmitted through the original image to form the photopolymerizable layer. After exposing the unexposed area to light, the unexposed area was attached by taking advantage of the fact that the adhesive force of the unexposed area to the substrate was smaller than the adhesive force of the exposed area to the substrate, and the adhesive force of the exposed area to the substrate was also smaller. In this state, the support film is peeled off, and an image is formed on the surface of the substrate, leaving only the exposed portion in close contact with the surface of the substrate.

However, the above-mentioned conventional materials have a serious problem in that satisfactory resolution cannot be obtained because the adhesion of the exposed portion to the substrate on which an image is to be formed is still insufficient. In particular, when used as a resist material for printed wiring, increasingly high resolution is required, but it is becoming difficult to meet such demands.

Furthermore, when etching a copper substrate with through holes, for example, the resist layer covering the through holes needs to be able to withstand the spray pressure of the etching solution, so the resist film thickness is relatively small. I have no choice but to make it thicker.
Therefore, the interface between the exposed and unexposed areas of the photopolymerizable layer is difficult to sharply cut, making it difficult to obtain an image with excellent resolution by peel development.

The present invention takes into consideration the current state of image forming materials as described above,
The purpose of this invention is to provide an image forming material that can obtain images with excellent resolution through release development, has excellent adhesion to the substrate surface, and does not cause problems such as peeling during etching. The gist is that it has a high molecular weight part with a number average molecular weight of 30,000 or more and a low molecular weight part with a number average molecular weight of 10,000 or less on a transparent support film, and has a weight average molecular weight / number average molecular weight (M w /
100 parts by weight of a resin binder whose main component is a synthetic resin having an M n ) value of 3.5 or more, 50 to 200 parts by weight of a photopolymerizable monomer that is liquid at room temperature, and 0.1 part by weight of a photopolymerization initiator.
The present invention provides an image forming material comprising a photosensitive layer comprising 10 parts by weight.

The transparent surface support film used in the present invention is selected from a film that has a uniform surface and good transmittance to light in the wavelength range of 300 to 500 nm that can photopolymerize the photopolymerizable layer. Terephthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride,
polyvinylidene chloride, polyamide, polycarbonate,
Cellulose triacetate, cellulose diacetate, polyvinyl alcohol, molephane, etc. are used, and polyethylene terephthalate is particularly preferably used.

The thickness of the film is not particularly limited, but is usually 10 to 1
50 microns, preferably in the range of 15 to 60 microns.

The photosensitive layer formed on the transparent support film is made of a mixture of a resin binder, a photopolymerizable monomer that is liquid at room temperature, and a photopolymerization initiator. The resin binder used in the present invention has a high molecular weight of 30,000 or more and a number average molecular weight of 30,000 or more. It has a low molecular weight part with a partial and number average molecular value of 10,000 or less, and the value of weight average molecular weight / number average molecular weight (Mw / M n ) is 3.5
The resin binder may contain a thermoplastic resin of a different type than the synthetic resin in an amount of 40% by weight or less, but It is preferable that the content of the thermoplastic resin is as low as θ~25 wt.

As the synthetic resin which is the main component of the resin binder, a polymer whose structural unit is an α,β-unsaturated ethylene monomer and whose molecular weight satisfies the above conditions can be used.

Examples of α,β-unsaturated ethylene monomers include aromatic vinyl compounds such as evastyrene, α-methylstyrene, and 2,4-dimethylstyrene; α-olefins containing unsaturated hydrocarbons; vinyl halides such as vinyl chloride, vinyl bromide, and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl tetrapionate, and vinyl butyrate;
Methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate,
n-octyl acrylate, acrylic acrylate, 2-ethyl acrylate Φyl, acrylic 7922-J) O-ethyl 6-yl, phenyl acrylate, α-lytetralua, methyl acrylate, ethyl methacrylate, propyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacrylate 9
lyl, 2-ethylhexyl methacrylate, IRyenyl methacrylate, dimethylaminoethyl methacrylate, methacrylic acid (or methacrylic acid) esters; acrylonitrile monomers such as acrylonitrile, methacrylonitrile, acrylamide, vinyl methyl ether, vinyl Vinyl ethers such as ethyl ether;
Examples include vinyl ketones such as vinyl methyl ketone and vinyl ethyl ketone, and N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, and N-vinylindole.

In the present invention, both homopolymers and copolymers of 2F4 or higher of the above monomers can be used as the synthetic resin, but acrylic acid (or methacrylic acid) esters are preferred in the present invention. and copolymers of aromatic vinyl compounds such as styrene and acrylic acid (or methacrylic acid) esters.

In order to prepare a synthetic resin that meets the above molecular weight characteristics in the present invention, the degree of polymerization distribution must have two peaks, one on the low molecular weight side and one on the high molecular weight side, and have a number average molecular weight of 10,000 or less on the low side + 7) and a high number average molecular weight of 10,000 or less. The number average molecular weight of the side is 30,000 or more, the overall M w
/M Polymers having a high molecular weight and an n value of 3.5 or more may be prepared separately and mixed uniformly so as to satisfy the above conditions.

In addition, the weight average molecular weight M w , number average molecular fil M n and their ratio M w / M n in the present invention are determined based on the method of gel permeation chromatography, and the solvent (tetrahydrofuran) is added every minute at a measurement temperature of 25°C. Flow at a flow rate of 1-, concentration 0, 4 f/dl
It means the value obtained from K when the sample solution of tetrahydrofuran is injected and measured at 8 points as the sample weight.

Next, as the photopolymerizable monomer that is liquid at room temperature, a monomer that is liquid at room temperature is used that initiates polymerization and hardens when exposed to light in the presence of a photopolymerization initiator, and usually pentaerythritol triacrylate, polyethylene glycol di Polyacrylate or polymethacrylate monomers such as acrylate, triethylene glycol diacrylate, polyethylene glycol dimethacrylate, polymethylene diacrylate, polymethylene dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and these monomers. Oligomerized polymers are preferably used.

Then, the photopolymerizable monomer is added to the resin binder 10.
50 to 200 parts by weight, preferably 80 parts by weight
It is used in a proportion of ~120 parts by weight. If the amount of the monomer used is less than 50 parts by weight, the unexposed portion will tend to stick to the surface of the substrate such as a copper plate during peeling development after exposure and will be difficult to transfer to the support film to be peeled off. Furthermore, if the amount of monomer used exceeds 200 parts by weight, it will take longer to cure by exposure to light, and the exposed areas will tend to adhere to the support film during peel development, so in either case, it will not be possible to obtain a good result. It is difficult to obtain images.

Next, the photopolymerization initiator may be any one having the property of activating the photopolymerizable monomer with actinic rays and initiating polymerization, and for example, the following compounds are effectively used. Namely, iodine compounds such as Fuji9mdimethyldithiocarbamate iodine, tetramethylthiclam monosulfide, diphenyl monosulfide, dipenzothiazoyl monosulfide, and butylphide; hydrazone, azobisisobutyronitrile, benzenediazonil chloride Azo and diazo compounds such as 02-ide; inorganic compounds such as zinc oxide, magnesium oxide, and tetraethyl lead; piacetyl, benzoin methyl ether, benzine ethyl ether, benzophenone, benzaldehyde, benzoin, benzyl anthra 10-quinone, 2-methyl anthra Quinone, 2-ethyl anthraquinone, 2-ternyabutyl anthraquinone, 2-
Aromatic carbonyl compounds such as aminoanthraquinone, 2-chloroanthraquinone, terephthalaldehyde; peroxides such as benzoyl peroxide, ditertiarybutyl peroxide, dicumyl peroxide, cumene hydroperoxide; cobalt chloride, cobalt acetate, Examples include inorganic ion complex compounds such as copper acetate, iron chloride, iron oxalate, cobalt acetylacetonate, cobalt naphthenate, and zinc naphthenate.

The photopolymerization initiator is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the resin binder.

As mentioned above, the image forming material of the present invention is formed by forming a photosensitive layer having a certain composition on a transparent support film. It is also possible to provide a protective layer.

The image-forming material of the present invention can be used for forming photoresist images and relief structures in the same manner as conventional products.
In particular, the photosensitive layer is laminated with the photosensitive layer side in contact with the surface of a substrate such as a copper plate on which an image is to be formed, and is brought into close contact with a hot roll, etc., and a negative film is placed on top of the substrate and exposed by irradiation with actinic light, after which the photosensitive layer is covered. By peeling off the support film, an image with excellent image quality is obtained.

The image forming material of the present invention has the structure as described above,
In particular, since the resin binder of the photosensitive layer is mainly composed of a synthetic resin with a specific molecular structure, the photosensitive layer cured by exposure to light has excellent adhesion to the surface of the substrate such as copper foil. At the same time, the separability of the unexposed part that adheres to the support film and is removed together with the film during one-peel development from the exposed part is also improved,
An image with excellent resolution can be obtained by peeling development. Furthermore, when used as a material for forming a photoresist, the improved adhesion improves the etching resistance of the photosensitive hardened layer, making it possible to perform highly accurate etching. It is effective when used in applications where this is required.

The present invention will be explained below based on Examples.

In addition, in the following, parts mean parts by weight.

Example I 100 parts of polymethyl methacrylate with Mw/Mn of 3.7, Mn of 50,000, Mn of the high molecular weight part being about 150,000, and Mu of the low molecular weight part of about 5000, an acrylic unsaturated compound To a mixture of 100 parts (trade name: oligoacrylate) TO-1, manufactured by Toagosei Co., Ltd., 5 parts of benzoyl methyl ether, 0.1 part of crystal violet, and 0.5 part of P-methoxyphenol, 1 part of methyl ethyl ketone/toluene was added. A mixed solvent was added so that the solid content was 30% by weight and dissolved uniformly to form a photosensitive liquid.
The film was coated onto a polyethylene terephthalate (PET) film with a film thickness of 813 mm after drying, and dried at 80°C for 5 minutes to form a photosensitive layer, thereby producing an image-forming material. Ta.

The photosensitive layer side of the forming material is placed on a kabura-phenol laminate,
It was bonded to copper foil using a hot roll.

This laminate was exposed from an IKw high pressure mercury lamp at a distance of 401 for 60 seconds through the original from the PET film side. Next, the exposed photosensitive layer and the film were peeled off from the copper-phenol laminate at a speed of 1.0 m 7 minutes at 20°C and at a peeling angle of 180°. The exposed areas were each transferred onto the film.

The thus obtained resist image on the copper foil was a hard, non-adhesive film with high clarity, and had good adhesion to the copper foil and did not peel off easily.

The resolution of this image is line spacing 120/, and the linear accuracy is ±20! Met.

Next, this was immersed in a 50-inch ferric chloride aqueous solution at 40°C to corrode the exposed copper foil, and then immersed in 14-dichloroethylene to take a resist image of the exposed area film. When removed, a good copper relief image with no defects was obtained.

In this way, the photosensitive material of this example also had good chemical resistance.

Comparative Example 1 Exposure was carried out in the same manner as in Example 1 except that 100 parts of polymethyl methacrylate having M w / M n of 1.5 and Mn of 100,000 was used instead of 100 parts of polymethyl methacrylate in Example 1. Adjust the solution and proceed as follows in Example 1.
When peeling and development was carried out in the same manner as above, a resist image was formed on the copper foil, but its resolution was only about 1/2 inch, which was very poor.

Example 2 Instead of 100 parts of polymethyl methacrylate in Example IK, M w / M n was 4.6, Mn was 20,000, Mn in the high molecular weight part was about 100,000, and M in the low molecular weight part was
Styrene-butyl acrylate copolymer with n of about 5,000 (
Composition weight ratio of styrene to butyl acrylate is 70:3
0) A photosensitive liquid was prepared in the same manner as in Example 1 except that 100 parts of the photosensitive solution was used.

Using this photosensitive solution, a photosensitive layer having a dry thickness of 20/20 mm was formed on a PET film in the same manner as in Example 1, and a copper-
After bonding with the phenol laminate, it was exposed to light and peeled off to obtain a good hardened resist image. The resolution of this image was 200z in line spacing, and the linear accuracy was ±30 houses.

Next, this was subjected to corrosion treatment in the same manner as in Example 1, and a good copper relief image without defects could be obtained.

Comparative Example 2 Instead of the styrene-butyl acrylate copolymer in Example 2, M w / M n was 2.5 and Mn was 18.
000 styrene-butyl methacrylate copolymer (styrene:butyl methacrylate is 70:30) and peel development was performed in the same manner, the resolution was 40.
There were 0 households.

Example 3.4 Instead of 100 parts of polymethyl methacrylate in Example IK, M w / M n is 5.4, Mn is 20,000, Mn in the high molecular weight portion is approximately 120,000, and Mn in the low molecular weight portion is
is about 5,000 styrene-methyl methacrylate-butyl acrylate copolymer (composition ratio of styrene: methyl methacrylate: butyl acrylate 50:20:30) 10
When peeling development was performed in the same manner as in Example 1 using 0 parts (
Example 3), similarly M w / M n is 18.2, M
n is 6200Kt, and Mn in the high molecular weight part is approximately 310,000,
In each case (Example 4) when 100 parts of a styrene-methyl methacrylate-butyl acrylate copolymer (composition ratio of styrene: methyl methacrylate: butyl acrylate 50: 20: 30) with a low molecular weight portion Mn of about 4500 was used. The resulting resist image on the copper foil had good adhesion and excellent resolution upon subsequent energization.

17- Example 34 Resolution 150 voices 100z Linear accuracy ±30 voices ±15/patent applicant Sekisui Chemical Co., Ltd. Representative: Mototoshi Fujinuma 18-

Claims (1)

[Claims] 1. A high molecular weight portion having a number average molecular weight of 30,000 or more and a low molecular weight portion having a number average molecular weight of 10,000 or less are formed on a transparent support film, and the weight average molecular weight/number average molecular weight (M w /
100 parts by weight of a resin binder whose main component is a synthetic resin having an M n ) value of 3.5 or more, 50 to 200 parts by weight of a photopolymerizable layer that is liquid at room temperature, and 0.0 parts by weight of a photopolymerization initiator.
An image forming material comprising a photosensitive layer comprising 1 to 10 parts by weight. 2. The image forming material according to item 1, wherein the main component of the resin binder is a polymer of acrylic acid (or methacrylic acid) ester. 3. Image forming material 0 according to item 1, wherein the main component of the resin binder is a copolymer of an aromatic vinyl monomer and an acrylic acid (or methacrylic acid) ester.