JP3199600B2 - Photosensitive resin composition and photosensitive element using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition and a photosensitive element using the same.

[0002]

2. Description of the Related Art Conventionally, in the field of manufacturing printed circuit boards, a photosensitive resin composition and a photosensitive element obtained using a support and a protective film have been widely used as a resist material for etching, plating and the like. Have been. The printed circuit board is formed by laminating a photosensitive film on a copper substrate, exposing it to a pattern, removing the unexposed portion with a developing solution, etching or plating to form a pattern, and curing the cured portion. It is manufactured by a method of peeling off from the substrate.

[0003] As a developing solution for removing the unexposed portion, an alkali developing type using a sodium hydrogen carbonate solution or the like is mainly used, and the developing solution usually has a capacity to dissolve the photosensitive layer to some extent. It is used, and at the time of use, the photosensitive resin composition is dissolved or dispersed in the developer. Due to the recent increase in the density of printed wiring boards, the contact area between the copper substrate and the patterned photosensitive layer has become smaller, so that excellent adhesive strength, mechanical strength, chemical resistance, Flexibility is required.

[0004] Among these types of properties, a method using a photopolymerizable compound having an isocyanurate ring to improve chemical resistance is disclosed in JP-A-61-77844 and JP-A-61-77844.
JP-A-2-290705, JP-A-61-14212, JP-A-59-222480, JP-A-1-14
No. 190, JP-A-57-55914, JP-A-5-216224, JP-A-5-273754, etc., have the disadvantage that the cured film is hard and brittle.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides an isocyanuric ring and (meth)
The use of a compound in which a flexible polyalkylene oxide group (polyethylene oxide group, polypropylene oxide group, etc.) and an alkylene group (hexamethylene group, etc.) are bonded between acrylates as an ethylenically unsaturated compound satisfies various requirements. Another object of the present invention is to provide a photosensitive resin composition having mechanical strength, chemical resistance and flexibility, and a photosensitive element using the same.

[0006]

The present invention comprises (A) a binder polymer having a carboxyl group, (B) a photopolymerizable compound having a polymerizable ethylenically unsaturated group in a molecule, and (C) a photoinitiator. Wherein the component (B) has the general formula (I)

Embedded image (Wherein, R ¹ represents a divalent organic group, and R ² represents a compound of the general formula (II)

Embedded image (Wherein, R ³ represents a hydrogen atom or a methyl group, X represents an alkylene oxide group, and n represents an integer of 1 to 14). About things. The present invention also relates to a photosensitive element obtained by applying the photosensitive resin composition on a support and drying the composition.

The photosensitive resin composition of the present invention comprises (A) a binder polymer having a carboxyl group, (B) a photopolymerizable compound having a polymerizable ethylenically unsaturated group in a molecule, and (C) a photoinitiator. And the component (B) contains the compound represented by the general formula (I) as an essential component.

The (A) binder polymer having a carboxyl group in the present invention includes, for example, (meth) acrylic acid ((meth) acrylic acid means methacrylic acid and acrylic acid; the same applies hereinafter). Copolymers with vinyl monomers that can be copolymerized are exemplified, and these copolymers are used alone or in combination of two or more.

The vinyl monomer is not particularly restricted but includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, methacrylic acid glycidyl ester, 2,2,2-
Trifluoroethyl (meth) acrylate ((meth) acrylate means acrylate and methacrylate; the same applies hereinafter), 2,2,3,3-tetrafluoropropyl (meth) acrylate acrylamide, diacetone acrylamide, styrene, vinyl Toluene and the like.

(A) The binder polymer having a carboxyl group is soluble or swellable in an aqueous alkaline solution (for example, an aqueous solution of 1 to 3% by weight of sodium carbonate or potassium carbonate). It is preferable from the point of view. Further, the acid value is preferably from 100 to 500. If the acid value is less than 100, the developing time tends to be slow, and if it exceeds 500, the developer resistance of the photocured resist tends to decrease. The weight-average molecular weight (calculated as polystyrene by GPC measurement) is 2
It is preferably from 000 to 300,000. If the weight average molecular weight is less than 30,000, the developer resistance tends to decrease, and if it exceeds 300,000, the development time tends to be long.

In the present invention, the compound represented by the above general formula (I), which is contained as an essential component in the (B) photopolymerizable compound having at least one polymerizable ethylenically unsaturated group in a molecule, In the general formula (I), the divalent organic group represented by R ¹ is not particularly limited.
Methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group, pentylene group, neopentylene group, hexylene group, heptylene group, octylene group, 2-ethyl-hexylene group, nonylene group, decylene group and the like. . In addition, R ² is a compound represented by the above general formula (I
In I), the alkylene oxide group represented by X is not particularly limited, and includes, for example, an ethylene oxide group, a propylene oxide group, a butylene oxide group, a pentylene oxide group, and a hexylene oxide group. And a propylene oxide group are preferred. In addition, as the bonding direction of the propylene oxide group,

Embedded image There are two types. In the above general formula (II), n is 1 to 1
It must be an integer of 4, and preferably 2 to 14. If n exceeds 14, the mechanical strength decreases.

The compound represented by the general formula (I) includes, for example, a compound represented by the general formula (II-1), (II-2) or (II-3), Formula (III)
And the like.

Embedded image (Wherein, R ³ and n have the same meanings as in general formula (II), and m is an integer of 3 to 6)

Embedded image (Wherein, R ¹ has the same meaning as in formula (I))

In the general formula (II-2), the propylene oxide unit of this block segment is
For the sake of notation, the bonding position of the methyl group is on the carbon atom next to the oxygen atom, but is not limited to this structure.

Embedded image Etc. shall be included.

As the compound represented by the above general formula (I), commercially available products, for example, NK oligo UA-21
(In the general formula (I), R ₂ = —CH ₃ , X = —CH ₂ CH ₂ O
−, N = 4 (average value), brand name of Shin-Nakamura Chemical Co., Ltd.),
NK oligo UA-41 (in the general formula (I), R ₂ = -C
_{H 3, X = -CH 2 -CH} (CH 3) -O- or -CH (CH
_{3) -CH 2 -O-, n =} 5 ( average value), Shin-Nakamura Chemical Co.
NK Oligo UA-42 (general formula (I))
R ₂ = —CH ₃ , X = —CH ₂ —CH (CH ₃ ) —O— or —CH (CH ₃ ) —CH ₂ —O—, n = 9 (average value), Shin-Nakamura Chemical Co., Ltd. (Trade name), NK Oligo UA-44
(In the general formula (I), R ₂ = —H, X = —CH ₂ —CH (C
H ₃₎ -O- or _{-CH (CH 3) -CH 2 -O-} , n = 6
(Average value), brand name of Shin-Nakamura Chemical Industry Co., Ltd.).

The compound other than the compound represented by the above general formula (I), which is an essential component in the component (B) in the present invention, includes, for example, polyhydric alcohols containing α, β-unsaturated carboxylic acids. (Polyethylene glycol di (meth) acrylate (having 2 to 14 ethylene groups)), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (Meth) acrylate, tetramethylolmethanetetra (meth) acrylate, polypropylene glycol di (meth) acrylate (having 2 to 14 propylene groups), dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) Acrylate, etc.), containing glycidyl groups Compound (bisphenol A) obtained by adding an α, β-unsaturated carboxylic acid to a compound
Bisphenol A dioxyethylene di (meth) such as dioxyethylene di (meth) acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A decaoxyethylene di (meth) acrylate
Acrylate, trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether acrylate, etc.), alkyl esters of (meth) acrylic acid (methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid Butyl ester, (meth) acrylic acid 2-ethylhexyl ester, etc.).

The (C) photoinitiator in the present invention includes:
For example, aromatic ketones (benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N, N'-tetramethyl-4,4'-diaminobenzophenone, 4-methoxy-4'- Dimethylaminobenzophenone, 2-ethylanthraquinone, phenanthrenequinone, etc.), benzoin (benzoin ether such as benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, methyl benzoin, ethyl benzoin, etc.), benzyl derivative (benzyl benzyl ketal, etc.), 2 , 4,5-Triarylimidazole dimer (2- (o-chlorophenyl) -4,
5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,
5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole 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.) and acridine derivatives (9-phenylacridine, 1,7-bis (9,9'-acridinyl) heptane, etc.) and the like. These are used alone or in combination of two or more.

The amount of the component (A) in the present invention is as follows:
Preferably, the amount is 40 to 80 parts by weight based on 100 parts by weight of the total of the components (A) and (B). When the compounding amount is less than 40 parts by weight, the photocured product is apt to become brittle,
When used as a photosensitive element, the coating properties tend to be poor, and if it exceeds 80 parts by weight, the sensitivity tends to be insufficient.

The amount of the component (B) in the present invention is as follows:
The amount is preferably 20 to 60 parts by weight based on 100 parts by weight of the total of the components (A) and (B). If the amount is less than 20 parts by weight, the sensitivity tends to be insufficient, and if it exceeds 60 parts by weight, the photocured product tends to be brittle.

The compounding amount of the compound represented by the general formula (I), which is an essential component in the component (B) in the present invention, is as follows:
It is preferably at least 3 parts by weight, more preferably from 5 to 40 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). If the amount is less than 3 parts by weight, sensitivity, adhesion, plating resistance and the like tend to be inferior.

The amount of the component (C) in the present invention is as follows:
The amount is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the total of the components (A) and (B). If the amount is less than 0.1 part by weight, the sensitivity tends to be insufficient. If the amount exceeds 20 parts by weight, the absorption on the surface of the composition during exposure increases, and the internal photo-curing increases. It tends to be insufficient.

The photosensitive resin composition of the present invention may contain a dye, a color former, a plasticizer, a pigment, a flame retardant, a stabilizer,
An adhesion imparting agent or the like can be added.

In the photosensitive resin composition of the present invention, each of the above components is dissolved in a solvent dissolving them, for example, toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, chloroform, methylene chloride, By dissolving and mixing in methyl alcohol, ethyl alcohol and the like, a uniform solution can be obtained.

The photosensitive element of the present invention can be produced by applying the photosensitive resin composition of the present invention on a support and drying the composition.

Examples of the support include a polymer film, for example, a film made of polyethylene terephthalate, polypropylene, polyethylene and the like.
Polyethylene terephthalate films are preferred. Since these polymer films need to be removed from the photosensitive layer later, they must not be surface-treated or made of a material that cannot be removed.

The thickness of these polymer films is 5 to 1
It is preferably set to 00 μm, more preferably 10 to 30 μm. These polymer films can be laminated on both sides of the photosensitive layer, one as a support film for the photosensitive layer and the other as a protective film for the photosensitive layer.

As a method for producing a photoresist image using the photosensitive element of the present invention, if the above-mentioned protective film is present, after removing the protective film,
A method of laminating by pressing the photosensitive layer on the substrate while heating the photosensitive layer may, for example, be mentioned. The surface to be laminated is usually a metal surface, but is not particularly limited.

The heating temperature of the photosensitive layer is not particularly limited.
The temperature is preferably set to 0 to 130 ° C. The pressure for pressing the photosensitive layer is not particularly limited, and is preferably 3 kg / cm ² . If the photosensitive layer is heated as described above, it is not necessary to pre-heat the substrate in advance, but the substrate may be pre-heated to further improve the lamination property.

The photosensitive layer thus completed in lamination is
It 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 it is, and if it is opaque, it must be removed naturally.

From the viewpoint of protection of the photosensitive layer, the polymer film is transparent, and the polymer film is left as it is.
Exposure through it is preferred.

As the active light, a light generated from a known active light source, for example, a carbon arc, a mercury vapor arc, a xenon arc or the like is used. The sensitivity of the photoinitiator contained in the photosensitive layer is usually maximum in the ultraviolet region, and in that case, the active light source preferably emits ultraviolet light effectively. When the photoinitiator is sensitive to visible light, for example, 9,10-phenanthrenequinone or the like, visible light is used as the active light, and the light source other than the above is used as the light source. Flood light bulbs for photography, sun lamps and the like are also used.

Next, after exposure, if a polymer film or the like is present on the photosensitive layer, the polymer film is removed, and then, using an aqueous alkali solution, for example, spraying, rocking immersion, brushing, scraping, etc. The unexposed portion is removed by a known method described above, and development is performed. Examples of the base of the alkaline aqueous solution include alkali hydroxides (such as hydroxides of lithium, sodium or potassium), alkali carbonates (such as carbonates or bicarbonates of lithium, sodium or potassium), and alkali metal phosphates (such as potassium phosphate). , Sodium phosphate, etc.), and alkali metal pyrophosphates (sodium pyrophosphate, potassium pyrophosphate, etc.), and an aqueous solution of sodium carbonate is preferable. The pH of the aqueous alkali solution used for development is preferably in the range of 9 to 11, and the temperature is adjusted according to the developability of the photosensitive layer. Also,
A surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating the development, and the like can be mixed in the alkaline aqueous solution.

Further, as a method of manufacturing a printed wiring board, there is a method of treating the surface of a substrate exposed by using a developed photoresist image as a mask by a known method such as etching and plating. The photoresist image can then be stripped, usually with an aqueous solution that is more alkaline than the aqueous alkaline solution used for development. As the strong alkaline aqueous solution, for example, an aqueous solution of 1 to 5% by weight of sodium hydroxide is used.

[0033]

The present invention will be described below with reference to examples. Examples 1 to 4 and Comparative Examples 1 to 3 The materials shown in Tables 1 and 2 were blended to obtain solutions.

[Table 1]

[Table 2]

The component (B) shown in Table 3 was dissolved in the obtained solution to obtain a solution of the photosensitive resin composition.

[Table 3]

In Table 3, the compounds used are: * 1: R in the general formula (I)¹Is -C₆H₁₂-, R^ThreeIs -CH_Three,
X is -CH_TwoCH_TwoO-, n are 4 (average) compounds, Shinnaka
* 2: R in the general formula (I)¹Is -C₆H₁₂-, R^ThreeIs -CH_Three,
X is -CH_TwoCH (CH _Three) -O- or -CH (CH_Three) -C
H_TwoO and n are compounds of 5 (average value) manufactured by Shin-Nakamura Kogyo Co., Ltd. * 3: In the general formula (I), R¹Is -C₆H₁₂-, R^ThreeIs -CH_Three,
X is -CH_TwoCH (CH_Three) -O- or -CH (CH_Three) -C
H_TwoO and n are compounds of 9 (average value) manufactured by Shin-Nakamura Kogyo Co., Ltd. * 4: In the general formula (I), R¹Is -C₆H₁₂-, R^ThreeIs -H, X
Is -CH_TwoCH (CH_Three) -O- or -CH (CH_Three) -CH_Two
O and n are compounds of 6 (average value) manufactured by Shin-Nakamura Kogyo Co., Ltd. * 5: Polypropylene glycol diacrylate (Shin-Nakamura
* 6: γ-chloro-β-hydroxypropyl-β′-meta
Acryloyloxyethyl-o-phthalate * 7: β-hydroxypropyl-β′-methacryloyl
Xyethyl-o-phthalate.

Next, the obtained solution of the photosensitive resin composition was uniformly applied on a 25 μm-thick polyethylene terephthalate film, and was applied to a hot air convection dryer at 100 ° C. for about 1 hour.
After drying for 0 minutes, a photosensitive element was obtained. The dried film thickness of the photosensitive resin composition layer was 50 μm.

On the other hand, the copper surface of a copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., trade name: MCL-E-61), which is a glass epoxy material having a copper foil (thickness: 35 μm) laminated on both sides, is # 6
Polishing using a polishing machine with a brush equivalent to 00 (manufactured by Sankei Co., Ltd.), washing with water, drying with an air stream, heating the obtained copper-clad laminate to 80 ° C. Was laminated while heating the photosensitive resin composition layer at 120 ° C.

Next, using an exposure machine (manufactured by Oak Co., Ltd.) HMW-201B having a high-pressure mercury lamp, a 21-stage stepper tablet as a negative was placed on the test piece and exposed at 60 mJ / cm ² . did. Next, the polyethylene terephthalate film was peeled off, and a 1% by weight aqueous solution of sodium carbonate was sprayed at 30 ° C. for 60 seconds to remove unexposed portions, and then the number of step tablets of the photocured film formed on the copper-clad laminate was measured. Was measured to evaluate the photosensitivity of the photosensitive resin composition. The results are shown in Table 4. The light sensitivity is indicated by the number of steps of the step tablet. The higher the number of steps of the step tablet, the higher the light sensitivity.

The adhesiveness was measured by measuring the line width (μm) remaining without being peeled off after the development, and the results are shown in Table 4. The smaller the value of the adhesion is, the smaller the line is, the less the line is peeled off from the copper-clad laminate, indicating that the line is in close contact with the copper-clad laminate, indicating a higher adhesion.

The plating resistance was evaluated by laminating as described above, exposing at a predetermined exposure amount, developing with the above developer, and then degreased (PC-455 (manufactured by Meltex Corporation) 25% by weight) for 5 minutes. Immersion → Rinse → Soft etch (ammonium persulfate 150g / L) for 2 minutes → Rinse →
Pretreatment was performed in the order of immersion in 10% by weight of sulfuric acid for 1 minute, and the resultant was placed in a copper sulfate plating bath (75 g / liter of copper sulfate, 190 g / liter of sulfuric acid, 50 ppm of chloride ion, 5 ml / liter of Copperglyme PCM (manufactured by Meltex Corporation)). Copper sulfate plating was performed at room temperature at 3 A / dm ² for 40 minutes. After that, it was washed with water, immersed in 10% by weight of borofluoric acid for 1 minute, and subjected to a solder plating bath (45% by weight of tin borofluoride 64 ml / l, 45% by weight of lead borofluoride 22 ml / l, 42% by weight of borofluoric acid) 200ml / liter, Plutin LA Conductivity Salt (Meltex)
20 g / liter, 41 ml / liter of Plutin LA starter (manufactured by Meltex Co., Ltd.), and subjected to solder plating at room temperature and 1.5 A / dm ² for 15 minutes.

In order to examine the plating resistance after washing and drying,
Immediately, a cellophane tape was applied and peeled off in the vertical direction (90 ° peel-off test). The presence or absence of peeling of the resist was observed, and the results are shown in Table 4. In addition, after the resist was peeled off, the presence or absence of undercut of the solder plating was observed from above by an optical microscope, and the results are shown in Table 4. In the case where the solder plating is buried, solder deposited by plating is observed below the transparent resist via the transparent resist.

Further, another test piece was subjected to a cross cut test (JIS-K-5400) after exposure and development with an exposure amount indicating 8 steps using a 21-step stepper tablet, and the results are shown in Table 4. Was.

[0043]

[Table 4]

As is clear from Table 4, Examples 1 to 4 within the scope of the present invention have good plating resistance and excellent adhesion and cross-cutting properties.

The photosensitive resin composition of the present invention has excellent adhesiveness, chemical resistance and flexibility. The photosensitive resin composition of the present invention can further obtain excellent photosensitivity and mechanical properties. With the photosensitive resin composition of the present invention, a composition having further excellent alkali developability can be obtained. The photosensitive element of the present invention is excellent in workability.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-64-24247 (JP, A) JP-A-3-160058 (JP, A) JP-A-59-222480 (JP, A) JP-A-5-222 273754 (JP, A) JP-A-2-34620 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F 7/027 G03F 7/033 H05K 3/06

Claims (10)

(57) [Claims] 1. A composition comprising (A) a binder polymer having a carboxyl group, (B) a photopolymerizable compound having a polymerizable ethylenically unsaturated group in a molecule, and (C) a photoinitiator, wherein the component (B) is General formula (I) (Wherein, R ¹ represents a divalent organic group, and R ² has the general formula (I
I) (Wherein, R ³ represents a hydrogen atom or a methyl group, X represents an alkylene oxide group, and n represents an integer of 1 to 14). object. 2. The photosensitive resin composition according to claim 1, wherein the compound represented by the general formula (I) as the component (B) is a compound wherein n in the general formula (II) is an integer of 4 to 9. . 3. The compound (B) according to claim 1, wherein X of the compound represented by the general formula (I) is an ethylene oxide group.
The photosensitive resin composition as described in the above. 4. The photosensitive resin composition according to claim 1, wherein X of the compound represented by the general formula (I) as the component (B) is a propylene oxide group. 5. The composition according to claim 1, wherein the component (A) is soluble or swellable in an aqueous alkali solution, has an acid value of 100 to 500, and a weight average molecular weight of 20,000 to 300,000. The photosensitive resin composition as described in the above. 6. The composition according to claim 1, wherein the component (A) is a copolymer of methacrylic acid and a vinyl monomer copolymerizable therewith.
The photosensitive resin composition according to any one of the above. 7. The photosensitive resin composition according to claim 1, wherein the photoinitiator of the component (C) is an aromatic ketone. 8. The use ratio of the component (A), the component (B) and the component (C) is such that the total amount of the component (A) and the component (B) is 100.
Component (A) is 40 to 80 parts by weight, and (B)
20 to 60 parts by weight of component and 0.1 to 20 of component (C)
The photosensitive resin composition according to any one of claims 1 to 7, wherein the photosensitive resin composition is 3 parts by weight or more of the compound represented by the general formula (I) in the component (B). 9. A photosensitive element obtained by applying and drying the photosensitive resin composition according to claim 1 on a support. 10. A photosensitive layer comprising the photosensitive resin composition according to claim 1 is laminated on a substrate, exposed and developed, and the unexposed portion of the surface of the substrate is treated by etching or plating. A method for manufacturing a printed wiring board, comprising: