JPS6398651A - Photosensitive resin composition and photosensitive laminated body using thereof - Google Patents

Abstract

PURPOSE:To obtain a photosensitive resin compsn. capable of providing a photosensitive laminated body having superior laminating characteristics to a base plate without requiring any preheating treatment of the base plate before the lamination by incorporating a specified amt. of water to the photosensitive resin compsn. developed with alkali. CONSTITUTION:The compsn. consists of 30-60wt% compd. having >=100 deg.C B.P. at atmospheric pressure and at least a kind of ethylenic unsatd. group, 35-65wt% linear copolymer including 20-40mol% COOH group and having 20,000-400,000 weight average mol.wt., 0.2-10wt% photoinitiator generating radicals by the irradiation with active rays, and 0.2-8wt% water. Suitable compds. having the ethylenic unsatd. group are tetraethyleneglycol di(meth) acrylate, polyethylene glycol di(meth)acrylate, etc. Suitable first monomer for the linear copolymer is, for example, acrylic acid, methacrylic acid, fumaric acid, etc., and suitable second monomer is, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a photosensitive resin composition and a photosensitive laminate using the same.

(Prior Art) Photoresists formed from photosensitive resin compositions have resistance to plating solutions and etching solutions, and are therefore used as resists when manufacturing printed wiring boards. These photosensitive resin compositions are usually used as a flexible three-layer laminate, that is, a photosensitive laminate consisting of a support film layer, a dried photosensitive resin composition layer (hereinafter referred to as photosensitive layer), and a protective film layer. It is being

As photosensitive resin compositions, both an alkali-developable type in which unexposed areas are removed (developed) with an alkaline aqueous solution and a solvent-developable type in which the unexposed areas are removed (developed) in an organic solvent are known.

When using a photosensitive laminate using an alkali-developable resin composition, first remove the protective film from the photosensitive laminate and use a printed wiring board substrate (hereinafter referred to as The photosensitive layer is heat-pressed (80 to 160°C,
2-4 kg/c) and laminate. The substrate consists of a metal foil laminated on an insulating layer, and is polished to remove moisture through pretreatment. Next, after imagewise exposure using a negative film or the like, unexposed areas are removed (developed) using an alkaline aqueous solution to form a photoresist image. Furthermore, a printed wiring board is manufactured by etching or plating a metal foil using the formed photoresist image as a mask, and then peeling off the photoresist image using an aqueous solution that is more strongly alkaline than the developer.

Heating of the substrate during lamination is carried out in order to improve adhesion (hereinafter referred to as lamination) when laminating the substrate and the photosensitive layer. However, if the substrate is taken out of the heating machine and left to stand, the temperature will drop, and on the other hand, if it is heated too much, an oxide film will form on the polished metal surface, which will conversely impair the lamination properties and the properties of printed wiring.

For this reason, it is necessary to control the heating time, standing time, heating temperature, etc. during the work, or to use specific equipment.In order to eliminate the trouble and equipment for such management, we developed a method that does not require heating the substrate and has excellent lamination properties. It is desired to develop a photosensitive laminate.

Conventionally, methods for softening photosensitive resin compositions in order to improve lamination properties include adding an external plasticizer, increasing the amount of an addition polymerizable substance, and plasticizing a polymeric binder. There is. However, even with these methods, a phenomenon in which the photosensitive layer oozes out from the edges of the roll (edge facing) occurs over time while the photosensitive laminate is wound up into a roll and stored. No good results have been obtained. Considering long-term storage stability, including during summer and transportation, the method of softening the photosensitive resin composition cannot be said to be preferable.

Further, as a means of improving lamination properties, it is conceivable to further increase the heating temperature for the photosensitive layer during lamination (hereinafter referred to as lamination temperature). However, in conventionally known photosensitive resin compositions, even if the lamination temperature is within the normal operating temperature range (90 to 160°C), a considerable amount of the components evaporate and scatter, and the scattered gas is toxic. It is generally desired to remove the exhaust air, and ducts are used. It is considered desirable to reduce the amount of this component scattered as much as possible.

Therefore, if the laminating temperature is raised to a higher temperature as described above, a large amount of the components will evaporate and scatter, producing smoke, which will actually be difficult to evacuate.In addition, the evaporation and scattering of the components will cause problems such as sensitivity, resolution, resistance to processing liquids, etc. The properties as a photoresist are significantly deteriorated. For this reason, the upper limit of the laminating temperature of conventionally known photosensitive laminates is 130 to 1
The temperature is 60°C, and it is considered practically impossible to raise the temperature beyond that.

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the drawbacks of the prior art described above, to provide a photosensitive laminate that does not require preheating treatment of the substrate before lamination, and has excellent lamination properties on the substrate. An object of the present invention is to provide a photosensitive resin composition and a photosensitive laminate using the same.

(Means for Solving the Problems) The present inventors have arrived at the present invention by discovering that the above object can be achieved by incorporating a predetermined amount of water into an alkali-developable photosensitive resin composition.

The present invention comprises (a) a compound having a boiling point of 100°C or higher at normal pressure and having at least one ethylenically unsaturated group in an amount of 30 to 60% by weight, and (b) a carboxyl group content of 20 to 40 mol%. , and 35 to 65% by weight of a linear copolymer with a weight average molecular weight of 20,000 to 400,000, (c) 0.2 to 10% by weight of a photoinitiator that generates radicals upon irradiation with actinic light, and (d) water. In a photosensitive resin composition containing 0.2 to 8% by weight of I and a photosensitive laminate in which a polymer film is laminated on at least one surface of the photosensitive layer, the photosensitive layer (a) has a A compound having a boiling point of 3° C. or higher and having at least one ethylenically unsaturated group is
(b) a linear copolymer having a carboxyl group content of 20 to 40 mol% and a weight average molecular weight of 20,000 to 400,000 to 35 to 65% by weight;
(c) 0.2 to 10% by weight of a photoinitiator that generates radicals upon irradiation with actinic light; and (d) 0.2 to 8% by weight of water.

In the photosensitive resin composition of the present invention, the photosensitive layer contains a compound (component (a)) having a boiling point of 100° C. or higher at normal pressure and having at least one ethylenically unsaturated group. This component (a) includes tetraethylene glycol di(meth)acrylate (meaning methacrylate or acrylate, the same applies hereinafter), polyethylene glycol di(meth)acrylate (having 2 to 14 ethylene groups), Methylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethanetri(meth)acrylate, tetramethylolmethanetetra(meth)acrylate, polypropylene glycol di(meth)acrylate (number of propylene groups is 2~ 14 things)
, a compound obtained by adding α,β-unsaturated carboxylic acid to a polyhydric alcohol such as dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc., trimethylolpropane triglycidyl 1,000-tert triacrylate , a compound obtained by adding α,β-unsaturated carboxylic acid to a glycidyl group-containing compound such as bisphenol A diglycidyl ether diacrylate, a polyhydric carboxylic acid such as phthalic anhydride, and β-hydroxyethyl (meth)acrylate. Esterified products with substances having hydroxyl groups and ethylenically unsaturated groups such as acrylic acid or methacrylic acid such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. Examples include alkyl esters.

Component (a) is 30 to 60% by weight in the photosensitive resin composition,
Preferably it is contained in an amount of 35 to 55% by weight.

If it is less than 30% by weight, the photocured product will not be sufficiently cured,
Resistance to plating solution and etching solution decreases, while 6
If it exceeds 0% by weight, the photocured product will have hard and brittle physical properties and will easily peel off from the substrate.

In the present invention, the photosensitive resin composition has a carboxyl group content of 20 to 40 mol% and a weight average molecular weight of 2 to 40 mol%.
It contains 10,000 linear copolymers (component (b)). This component (b) is obtained by polymerizing two or more monomers, and the monomer is thick (divided into two parts. The first monomer is the linear copolymer. (Binding agent), such as acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, sorbic acid, propiolic acid, itaconic acid, maleic acid, maleic anhydride,
It is a carboxylic acid or acid anhydride having one unsaturated group such as maleic acid half ester.

The second monomer is one that imparts resistance to plating solutions, etching solutions, etc. to the linear copolymer (binder), or imparts developer resistance, flexibility, and plasticity; Those having one unsaturated group are used, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,
Alkyl acrylates or alkyl methacrylates such as butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, esters of vinyl alcohols such as vinyl-n-butyl ether, substituted in the α-position or in the aromatic ring Examples include polymerizable styrene derivatives, styrene, and the like.

It is preferable to use acrylic acid or methacrylic acid as the first monomer, and it is preferable to use alkyl acrylate or alkyl methacrylate as the second monomer.

The first monomer and the second monomer are copolymerized so that the carboxyl group content of the linear copolymer obtained is 2.
The content is selected to be 0 to 40 mol%. In order to set the carboxyl group content in the range of 20 to 40 mol%, the first monomer is used in an amount of 20 to 40 mol% based on the total amount of the first monomer and the second monomer. Bye. This carboxyl group content is important as a determining factor for developability; if it is less than 20 mol%, development will not be possible, while if it exceeds 40 mol%, the resistance of the exposed area to the developer will decrease, resulting in poor development. No resist image is formed. In this case, the carboxyl group may be an acid anhydride group.

In this case, the acid anhydride group is treated as two carboxyl groups. The method for synthesizing this copolymer is not particularly limited and can be any conventional synthesis method such as solution radical polymerization.

The molecular weight of the linear copolymer contributes to film-forming properties, and is also a factor that secondarily determines developability and resistance to processing solutions. The molecular weight range of this linear copolymer is from 20,000 to 400,000, preferably from 30,000 to 300,000 in weight average molecular weight. The molecular weight during the synthesis of the copolymer can be adjusted in a conventional manner by adjusting the synthesis temperature, the amount of the catalyst, the monomer concentration during the synthesis, etc. When it is less than 20,000, film forming properties are impaired and resistance to processing solutions including developing solutions is reduced, while when it exceeds 400,000, film forming properties and resistance are very good, but developability is reduced. do.

Component (b) is 35 to 65% by weight in the photosensitive resin composition,
Preferably it is contained in an amount of 40 to 60% by weight.

If it is less than 35% by weight, the film forming properties of the photosensitive layer obtained will be impaired and sufficient film strength will not be obtained, while if it exceeds 65% by weight, the photocured film will be brittle and the adhesion to the substrate will be poor. be damaged.

In the present invention, the photosensitive resin composition contains a photoinitiator (component (c)) that generates radicals upon irradiation with actinic light. Component (c) is preferably a substance that is not thermally activated at temperatures below 200°C and has extremely low volatility, such as 2-ethylanthraquinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1. 2
- Substituted or unsubstituted polynuclear quinones such as benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, and 2,3-diphenylanthraquinone are used.

Also, Vic-ketaldonyl compounds such as diacetyl and benzyl, α-ketaldonyl alcohols such as benzoin, vivaloin, and ethers, such as α-phenyl-benzoin, α, α-jethoxyacetophenone, etc.
hydrocarbon-substituted aromatic acyloins, aromatic ketones such as 4,41-bisdialkylamino-benzophenone;
Furthermore, 2.4.5-) Realyl imidazole dimer and 2-mercaptobenzoxazole, leuco crystal,
Combinations with violet, tris(4-diethylamino-2-methylphenyl)methane, etc. are also used as component C.

Component (c) is 0.2 to 10% by weight in the photosensitive resin composition.
Contains. If the amount is 0.2% by weight, sufficient photocuring will not be obtained, while if it exceeds 10% by weight, thermal instability will result.

In the present invention, the photosensitive resin composition contains water as component (d) in an amount of 0.2 to 8% by weight, preferably 0.5 to 6% by weight. By containing water, lamination properties on a substrate at room temperature are improved. When the amount of water is 0.2% by weight without grooves, sufficient lamination properties cannot be obtained and the photosensitive layer obtained after lamination is likely to peel off.On the other hand, when the amount of water exceeds 8% by weight, when producing the photosensitive layer, Repelling is likely to occur in the photosensitive layer.

The photosensitive resin composition preferably contains a radical polymerization inhibitor in order to prevent thermal polymerization during the heating process and during storage. Examples of the radical polymerization inhibitor include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, phenothiazine, pyridine, nitrobenzene, dinitrobenzene, p-)luquinone,
Chloranil, aryl phosphite, etc. are used.

Those with low volatility below 200°C, such as alkyl-substituted hydroquinone, t-butylcatechol, cuprous chloride, 2
．． 6-di-t-butyl-p-cresol, 2,2-methylenebis(4-ethyl-6-t-butylphenol),
2.2-methylenebis(2-methyl-6-t-butylphenol) and the like are preferred.

The photosensitive resin composition may contain coloring substances such as dyes and pigments. The coloring substance is preferably one that does not affect the properties of the photoresist and does not decompose or volatilize at temperatures below 200°C. For example, Tsuksin, Auramine Base, Calcocyto Green S, Paramazienta, Crystal Violet, Methyl Orange, Nile Blue 2B.

Victoria Pure Blue, Malachite Green, Paythic Blue 20. Iosing Green, Night Green B,) Riparosan, Pneumagienta, Acid Violet RRH, Red Violet 5RS, New Methylene Blue CG, etc. are used.

Furthermore, additives such as plasticizers and adhesion promoters may be added to the photosensitive resin composition.

The photosensitive laminate of the present invention has a polymer film laminated on at least one surface of a photosensitive layer containing the components (a) to (d). As this polymer film, for example, a film made of polyethylene terephthalate, polypropylene, or polyethylene is used, and a polyethylene terephthalate film is preferable. Since these polymer films must be removable from the photosensitive layer later, they must not be made of a material or have a surface treatment that makes it impossible to remove them. The thickness of these polymer films is 5 to 100 μm, preferably 10 to 3
It is 0 μm. One of these polymer films may be laminated on both sides of the photosensitive layer as a support film for the photosensitive layer, and the other as a protective film for the photosensitive layer.

When manufacturing the photosensitive laminate of the present invention, first, a photosensitive resin composition consisting of components (a) to (d) is uniformly dissolved in a solvent. The solvent may be any solvent that dissolves the photosensitive resin composition, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, dichloromethane, chloroform, methyl alcohol, ethyl alcohol, and the like. These solvents may be used alone or in combination of two or more.

Next, after uniformly applying the photosensitive resin composition in solution form onto the polymer film as the support film layer,
Remove the solvent by heating and/or blowing hot air;
Dry film. There is no particular limit to the thickness of the dry film;
The thickness is 10 to 100 μm, preferably 20 to 60 μm.

The photosensitive layer and polymer film thus obtained
The photosensitive laminate of the present invention made of N can be stored as it is or by further laminating a protective film on the other surface of the photosensitive layer and winding it up into a roll.

When producing a photoresist image using the photosensitive laminate of the present invention, if the protective film is present, after removing the protective film, the photosensitive layer is laminated by pressing the photosensitive layer onto the substrate while heating. do. The surface to be laminated is a metal surface, but is not particularly limited. Heating and pressure bonding of the photosensitive layer is usually 90 to 130°C and pressure 3.
kg/cnl, but these conditions are not particularly limited.

When using the photosensitive laminate of the present invention, it is not necessary to preheat the substrate if the photosensitive layer is heated as described above. Of course, it is also possible to preheat the substrate in order to further improve lamination properties.

The photosensitive layer thus laminated is then imagewise exposed to actinic light using a negative or positive film. At this time, if the polymer film present on the photosensitive layer is transparent, it may be exposed as is, or if it is opaque, it must be removed. From the point of view of protecting the photosensitive layer, it is preferable that the polymer film is transparent and exposed through it while the polymer film remains. As the active light, light emitted from a known active light source such as a carbon arc, a mercury vapor arc, a xenon arc, or the like is used. Since the sensitivity of the photoinitiator contained in the photosensitive layer is usually greatest in the ultraviolet region, in that case the active light source should be one that effectively emits ultraviolet light. Of course, if the photoinitiator is sensitive to visible light, such as 9゜10-finanthrenequinone, then visible light is used as the active light, and the light source for this is other than those mentioned above. Flood light bulbs, solar lamps, etc. are also used.

After exposure, if a polymer film is present on the photosensitive layer, it is removed, and unexposed areas are removed using an alkaline aqueous solution by a known method such as spraying, oscillating dipping, brushing, or scraping. develop. The base for the alkaline aqueous solution includes alkali hydroxides such as hydroxides of lithium, sodium, and potassium; alkali carbonates such as carbonates or bicarbonates of lithium, sodium, and potassium;
Alkali metal phosphates such as potassium phosphate and sodium phosphate, alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate are used, and an aqueous solution of sodium carbonate is particularly preferred.

The pH of the alkaline aqueous solution used for development is preferably 9 to 9.
11, and the temperature is adjusted depending on the developability of the photosensitive layer. A surfactant, an antifoaming agent, and a small amount of an organic solvent for accelerating development may be mixed into the alkaline aqueous solution.

Further, when manufacturing a printed wiring board, the exposed surface of the substrate is processed by known methods such as etching and plating using the developed photoresist image as a mask. The photoresist image is then typically stripped with an aqueous solution more strongly alkaline than the aqueous alkaline solution used for development. As this strongly alkaline aqueous solution, for example, 2 to 10% by weight of sodium hydroxide is used.

(Effects of the Invention) A laminate in which the photosensitive resin composition of the present invention is used as a photosensitive layer does not require heating of the substrate during lamination, and has excellent lamination properties to the substrate.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples below, % means weight %.

Example 1 A solution (solution A) having the composition shown in Table 1 was uniformly applied onto a 25 μm thick polyethylene terephthalate film using the apparatus shown in FIG. The solvent was removed by drying at 7) for about 3 minutes.

In Figure 1, 1 is a polyethylene terephthalate film feeding roll, 2.3.4°, 9.10 is a roll,
5 is a knife, 6 is a solution of a photosensitive resin composition, 8 is a polyethylene film feeding roll, and 11 is a photosensitive film winding roll. The thickness of the photosensitive layer after drying is approximately 25
It was μm. Further, the moisture content in the photosensitive layer was measured by Karl Fischer method and was found to be 3%.

Next, a polyethylene film was laminated as a protective film on the photosensitive layer using the apparatus shown in FIG. 1 to obtain a photosensitive laminate of the present invention.

A substrate for printed wiring boards (trademark MCL-E- manufactured by Hitachi Chemical Co., Ltd.), which is a glass epoxy material laminated with copper plates on both sides.
The copper surface of No. 61) was polished with a cleanser, washed with water, and dried with a stream of air. This substrate (23°C) was laminated at a laminating temperature of 110°C and a laminating pressure of 3 kg/C using a laminator (model HLM-1500) manufactured by Hitachi Chemical Co., Ltd.
The photosensitive laminate was laminated with IA. Immediately after lamination, the photosensitive layer was pulled by hand, but the photosensitive layer was in close contact with the substrate and did not peel off.

Next, the obtained sample was exposed to a 3 KW high pressure mercury lamp from a distance of 90 CI 11 for 60 seconds using a negative film.

Development is done after removing the polyethylene terephthalate film.
This was done in about 40 seconds by spraying a 2% aqueous solution of sodium carbonate at 25° C., and showed good developability.

Furthermore, the obtained photoresist image has good resolution capable of resolving line widths up to 80 μm, and can be etched using ordinary etching solutions such as ferric chloride, cupric chloride, and ammonium persulfate.
Or, it had sufficient resistance under normal treatment conditions of solder plating solution and copper sulfate plating solution.

The storage stability of the photosensitive laminate of the present invention was examined by placing it in a thermostat at 40°C, but no abnormal changes were observed even after one month, and no abnormality in properties was observed even after reuse. It showed good storage stability.

Margin below Table 1 *Carboxyl fund amount 24.7 mol% Weight average molecule t
85000 Comparative Example 1 A photosensitive laminate was obtained by using a solution from which water was removed from among the components of solution A, and otherwise treating the same as in Example 1. Further, the photosensitive laminate was laminated onto the same substrate as in Example 1 using the same laminator. When the photosensitive layer was pulled by hand immediately after lamination, the photosensitive layer peeled off from the substrate.

Separately, a sample laminated with a photosensitive layer was exposed and developed in the same manner as in Example 1, but the resolution of the resulting photoresist image was up to 150 μm in line width, and lines thinner than that had poor adhesion. It was missing during development due to a shortage.

Example 1 and Comparative Example 1 show that the photosensitive laminate of the present invention has sufficient lamination properties on substrates at room temperature (23° C.) without heating the substrates during lamination.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus for manufacturing a photosensitive laminate used in Examples. 1... Polyethylene terephthalate film feeding roll, 2.3.4, 9.10... Roll, 5...
Knife, 6... Solution of photosensitive resin composition, 7... Dryer, 8... Polyethylene film feed roll,
11... Photosensitive film winding roll.

Claims (1)

[Claims] 1. (a) 30 to 60% by weight of a compound having a boiling point of 100°C or higher at normal pressure and having at least one ethylenically unsaturated group; (b) a carboxyl group content; 20 to 40 mol% and a weight average molecular weight of 20,000 to 400,000 to 35 to 65
(c) 0.2 to 10 weight % of a photoinitiator that generates radicals upon irradiation with actinic light; and (d) 0.2 to 8 weight % of water. 2. In a photosensitive laminate in which a polymer film is laminated on at least one side of the photosensitive layer, the photosensitive layer (a) has a boiling point of 100°C or higher at normal pressure, and has at least one type of ethylenically unsaturated (b) a linear copolymer having a carboxyl group content of 20 to 40 mol% and a weight average molecular weight of 20,000 to 400,000 to 35 to 65% by weight of a compound having groups;
(c) 0.2 to 10 weight % of a photoinitiator that generates radicals upon irradiation with actinic light; and (d) 0.2 to 8 weight % of water.