JPH0675371A - Photosensitive resin composition and photosensitive element using the same - Google Patents

Abstract

PURPOSE:To obtain excellent resistance to plating and to prevent the generation of the scum of development by incorporating specified ethylenic unsatd. compd., org. halogen compd., film-property imparting polymer and a photoinitiator and/or photoinitiators. CONSTITUTION:The photosensitive resin contains at least one ethylenic unsatd. compd. expressed by the formula, org. halogen compd., film-property imparting polymer and photoinitiator which can generate free radical by active ray and/or photoinitiators, and the element consists of the layers of the composition and the supporting body film which supports the layers. In the formula, each of R1 and R4 is hydrogen atom or methyl group independently, each of R2 and R3 is ethylene group or propylene group, but R2 and R3 is inevitably different from each other, if R2 is propylene group, (m)is integer 1-2 and (n) is integer >=1, if R3 is propylene group, (n) is integer 1-2 and (m) is integer >=1.

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 used for producing printed wiring boards and the like and a photosensitive element using the same.

[0002]

2. Description of the Related Art In the field of printed wiring board manufacturing, a photosensitive composition and a photosensitive element using the same are used as resist materials when chemical or electrical treatments of substrates such as etching and plating are used. It is known. As the photosensitive element, one in which a photosensitive resin composition is laminated on a support is widely used.

Conventionally, as a method of manufacturing a printed wiring board, two methods known as a tenting method and a plating method are known. The tenting method protects the copper through holes for chip mounting with a resist and forms an electric circuit through etching and resist removal, whereas the plating method uses electroplating to deposit copper in the through holes and then solder. It is a method of protecting by plating and forming an electric circuit by resist stripping and etching.

Therefore, the properties required of the photosensitive resin composition used are strong adhesion to metals, chemical resistance to etching solutions and plating chemicals, peelability and the like.

Japanese Examined Patent Publication No. 64-5691 discloses the following formula (II):

[Chemical 2] A photosensitive resin composition having strong adhesion to a substrate and excellent plating resistance is disclosed by using an ethylenically unsaturated compound represented by (R ₁ , R ₂ , R ₃ and R). ₄ is H or CH ₃ ). However, when an ethylenically unsaturated compound having a polyethylene glycol chain of R ₂ = R ₃ = H is used, plating resistance is excellent, but resist releasability and flexibility are still insufficient. Also, R ₂ = R ₃ = CH
_{When the} ethylenically unsaturated compound having a polypropylene glycol chain of ₃ is used, although it has good flexibility, there are problems such as deterioration of the resist shape and reduction of sensitivity.

Further, Japanese Patent Application Laid-Open No. 4-88345 discloses that
Formula (III) below

[Chemical 3] There is disclosed a photosensitive resin composition using an ethylenically unsaturated compound represented by (R ₁ and R ₂ are H or CH ₃ ,
A and B are different from each -CH (CH ₃₎ CH ₂ - or -C
_{H 2 CH 2 -, m 1} + m 2 and n ₁ + n ₂ is 6-12 positive integer). However, A or B is -CH (CH ₃₎ CH ₂
In the case of −, if the total sum of the oxypropylene groups exceeds 4, the shape of the peeling piece becomes large, the tenting property is deteriorated, and it easily separates in an alkaline developer, causing scum, and when attached to the substrate, There are problems such as short circuit and disconnection.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has excellent plating resistance, flexibility and peelability and does not cause development scum and a photosensitive resin composition. A photosensitive element using the same is provided.

[0008]

The present invention provides (A) general formula (I)

[Chemical 4] [In the formula, R ₁ and R ₄ each independently represent a hydrogen atom or a methyl group, R ₂ represents an ethylene group or a propylene group, R ₃ represents an ethylene group or a propylene group, and R ₂ and the R ₃ an always different groups, when R ₂ is a propylene group and m is 1-2 integer, n is an integer of 1 or more, R ₃
Is a propylene group, n is an integer of 1 to 2 and m is an integer of 1 or more], (B) an organic halogen compound, (C) a film property imparting agent. From a photosensitive resin composition comprising a polymer and (D) a photoinitiator capable of generating free radicals by actinic radiation and / or a photoinitiator system, a layer of the composition and a support film supporting the same To a photosensitive element.

Next, the photosensitive resin composition of the present invention will be described in detail. First, the ethylenically unsaturated compound as the component (A) is a compound in which R ₁ and R ₄ represent hydrogen or a methyl group in the general formula (I), and there are acrylate compounds and methacrylate compounds. When R ₂ is a propylene group, m is an integer of 1 to 2 and n is an integer of 1 or more.
When m is 3 or more, the shape of the peeled piece becomes large, the tenting property is deteriorated, and separation in the alkaline developer is easy, which is a disadvantage because scum occurs. When R ₃ is a propylene group, n is an integer of 1 to 2 and m is an integer of 1 or more. When n is 3 or more, the shape of the peeled piece becomes large, the tenting property is deteriorated, and separation in the alkaline developer is easy, which is a disadvantage because scum occurs. The sum of m and n is preferably 3-10. When the sum of m and n is less than 3, flexibility tends to decrease, and when the sum of m and n exceeds 10, the resist shape tends to deteriorate. Incidentally, -R ₃ O-and -R ₂ O-group in the general formula (I) is not necessarily each have to be present the n consecutive and m successively with this position. That is, they may be present at random or may be present in a block manner, and the abundance ratio may be m / n. The ethylenically unsaturated compound represented by the general formula (I) can be used alone or in combination of two or more kinds.

In the photosensitive resin composition of the present invention,
The ethylenically unsaturated compound represented by the above general formula (I) which is the component (A) is preferably used in an amount of 5 to 60% by weight based on the film property imparting polymer which is the component (C). If the amount of the component (A) is less than 5% by weight, the sensitivity tends to be insufficient, and if it exceeds 60% by weight, the fluidity of the photosensitive resin composition tends to increase.

In the photosensitive resin composition of the present invention, a conventionally used ethylenically unsaturated compound can be added in addition to the ethylenically unsaturated compound represented by the above general formula (I), and the sensitivity is improved. The use of an acrylate monomer or a methacrylate monomer is preferable from the viewpoint of high
For example, trimethylolpropyne triacrylate, pentaerythritol triacrylate, 1,6-hexanediol diacrylate, 2,2-bis (4-methacryloxyethoxyphenyl) propane, 2,2-bis (4
-Polyacrylate or polymethacrylate of polyhydric alcohol such as acryloxyethoxyphenyl) propane, dipentaerythritol pentaacrylate, trimethylolpropane trimethacrylate, adduct of trimethylolpropane triglycidyl ether with acrylic acid or methacrylic acid, bisphenol A: Epoxy chlorohydrin type epoxy resins such as acrylic acid or methacrylic acid adducts and other epoxy acrylates, and phthalic anhydride-neopentyl glycol-acrylic acid in the form of a 1: 1: 2 mole ratio low molecular weight unsaturated polyester and the like. To be

(B) in the photosensitive resin composition of the present invention
As the organic halogen compound as a component, those which easily release halogen radicals by actinic light or those which easily release halogen radicals by chain transfer are preferable, and these give preferable results such as improved sensitivity. Examples of the component (B) include carbon tetrachloride, chloroform, bromoform, 1,1,1-trichloroethane, methylene bromide, methylene iodide, methylene chloride, carbon tetrabromide, iodoform, 1,1,2,2. -Tetrabromoethane, pentabromoethane, tribromoacetophenone, bis- (tribromomethyl) sulfone, vinyl chloride, chlorinated olefins and the like. Among these, an aliphatic halogen compound having a weak carbon-halogen bond strength, particularly a compound in which two or more halogen atoms are bonded on the same carbon, particularly an organic bromine compound is preferable.
Organohalogen compounds having a tribromomethyl group give more favorable results.

The polymer imparting film property used as the component (C) is not particularly limited, but a high molecular weight polymer obtained by vinyl copolymerization is preferable. Examples of the vinyl polymerizable monomer used in the vinyl copolymer include methyl methacrylate, butyl methacrylate, α-ethylhexyl methacrylate, lauryl methacrylate, ethyl acrylate, methyl styrene acrylate, vinyltoluene, and N-vinylpyrrolidone. , Α-methylstyrene, α-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate,
Examples thereof include acrylamide, acrylonitrile, dimethylaminoethyl methacrylate and dimethylaminoethyl acrylate.

The amount of component (C) used is preferably 20 to 90 parts by weight, more preferably 50 to 80 parts by weight, based on 100 parts by weight of the total amount of the photosensitive resin composition. If the amount of the component (C) used is too small, it tends to be difficult to improve the coating property and developability and to reduce the occurrence of edge fusion, and if it is too large, the sensitivity tends to decrease.

The photoinitiator and photoinitiator system which generate free radicals by the actinic rays as the component (D) are not particularly limited, and conventionally known ones can be used. For example, benzophenones such as benzophenone, 4,4′-dimethylaminobenzophenone, 4,4′-diethylaminobenzophenone and 4,4′-dichlorobenzophenone, anthraquinones such as 2-ethylanthraquinone and t-butylanthraquinone, 2-chloro One or two or more of thioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzyl, 2,4,5-triallyl-imidazole dimer (rophin dimer), acridine compound and the like can be used.

The amount of the component (D) used is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the total amount of the photosensitive resin composition. preferable. If the amount used is too small, there is a tendency that sufficient photosensitivity cannot be obtained, and if the amount is too large, the light absorption on the surface of the composition during exposure tends to increase and the internal photocuring tends to be insufficient. is there.

There are no particular restrictions on the mixing order and mixing method of the components (A) to (D) as described above. It should be noted that the photosensitive resin composition of the present invention may contain other auxiliary components, such as dyes, pigments, plasticizers, flame retardants, and stabilizers, if necessary. Also, an adhesion-imparting agent can be used.

Next, the photosensitive element of the present invention will be described in detail. The photosensitive element of the present invention can be obtained by laminating a layer of the photosensitive resin composition on a support film. The photosensitive resin composition layer can be formed on the support film by a conventional method.
For example, the photosensitive resin composition is uniformly dissolved in an organic solvent such as methyl ethyl ketone, toluene, and methylene chloride, and this solution is applied onto the support film by knife coating, roll coating, spray coating, spin coating, or the like. It is carried out by applying and drying. The amount of residual solvent in the photosensitive layer is preferably suppressed to 2% by weight or less in order to maintain the characteristics.

The support film used in the present invention preferably has the heat resistance and solvent resistance required for the production of the photosensitive element, but a release film such as Teflon film or release paper is temporarily used. After forming a layer of the photosensitive resin composition thereon, a film having low heat resistance or solvent resistance is laminated on the layer, and the temporary support film is peeled off. It is also possible to produce a photosensitive element having a support film having low heat resistance or solvent resistance. Further, the support film may be transparent or opaque to actinic light. Examples of the support film that can be used include known films such as polyester film, polyimide film, polyamideimide film, polypropylene film and polystyrene film.

When producing a long photosensitive element, the element is wound into a roll at the final stage of production. In this case, by using a known method with a pressure-sensitive adhesive tape or the like, by using a backside treated support film,
It is possible to prevent transfer of the layer of the photosensitive resin composition to the back surface of the support film when wound in a roll. For the same purpose, and further for the purpose of preventing the adhesion of dust, it is preferable to laminate a peelable cover film on the layer of the photosensitive resin composition of the element. Specific examples of the peelable cover film include polyethylene film, polypropylene film, Teflon film, surface-treated paper, and the like, and the adhesive force between the layer of the photosensitive resin composition and the support film when the cover film is peeled off. The adhesive force between the layer of the photosensitive resin composition and the cover film may be smaller than that.

The thickness of the layer of the photosensitive resin composition constituting the photosensitive element of the present invention varies depending on the thickness of plated copper deposited by electroless plating, but is usually 10 to 10.
It is set to 0 μm. The photosensitive resin composition of the present invention is applied as a solution onto a substrate, and after drying or as a photosensitive element, a layer of the photosensitive resin composition is laminated on the substrate, imagewise exposed and developed. To produce a plating resist.

The exposure and development processing after lamination can be carried out by a conventional method. That is, when the support film is opaque to actinic light, the support film is peeled off and then imagewise exposed through a negative mask using a light source such as a high pressure mercury lamp or an ultrahigh pressure mercury lamp. Heat treatment at 50 to 100 ° C. before and after exposure is preferable in order to improve the adhesion between the substrate and the photosensitive resin layer.

As the developing solution used in the developing treatment, an aqueous alkali solution is used, for example, an aqueous solution of an alkali metal hydroxide, an aqueous solution of an alkali metal phosphate, an aqueous solution of an alkali metal carbonate such as sodium carbonate. Is mentioned. Particularly, an aqueous solution of sodium carbonate is preferable. In the alkali development of the resin composition of the present invention, the developer temperature is 10 to 10.
It can be carried out at a temperature of 50 ° C., preferably 20 to 40 ° C., using a commercially available developing machine.

After the plating resist pattern is formed in this way, it is preferable to re-irradiate with active light using a light source such as a high pressure mercury lamp or an ultrahigh pressure mercury lamp, which improves the chemical resistance of the plating resist. Further, the solution of the photosensitive resin composition of the present invention is directly applied to the substrate by a method such as a dip coating method or a flow coating method, and after drying the solvent, directly or after laminating a film transparent to active light such as a polyester film. In the same manner as in the case of the photosensitive element, a plating resist having excellent characteristics can be formed by imagewise exposing through a negative mask, developing, and more preferably exposing with actinic light.

[0025]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. Reference Example 1 (Production of Film-Providing Polymer) 500 ml of a solution of methyl cellosolve / toluene = 3: 2 (weight ratio) (hereinafter referred to as solution A) was placed in a flask, heated to 85 ° C. and left for 1 hour. . Thereafter, 23.7 g of methacrylic acid, 46.8 g of methyl methacrylate, 31.2 g of ethyl acrylate, 1.5 g of 2-ethylhexyl acrylate and 0.17 of azobisisobutyronitrile.
What melt | dissolved g in solution A31.2g was dripped over 4 hours, and was made to react.

Then, 7.1 g of methyl cellosolve was added, and the mixture was kept warm for 2 hours. A solution prepared by dissolving 0.6 g of methacrylic acid and 0.54 g of azobisisobutyronitrile in 4.8 g of solution A was added to the reaction solution, and further 2 I kept it warm for an hour. Then, a solution of 0.024 g of azobisisobutyronitrile dissolved in 1.2 g of methyl cellosolve was added and kept warm for 5 hours, and then a solution of 0.01 g of hydroquinone dissolved in 0.2 g of methyl cellosolve was added and cooled. . The obtained polymer is hereinafter referred to as a polymer. The polymer has a nonvolatile content of 38.5% by weight and a Gardner viscosity of 1 at 25 ° C.
It had a weight average molecular weight of 84,000 for 10 seconds. In addition,
This weight average molecular weight is a value measured by gel permeation chromatography and converted using a calibration curve of standard polystyrene.

Examples 1 to 8 and Comparative Examples 1 to 5 A photosensitive resin composition solution was prepared according to the formulation (unit: parts by weight) shown in Table 1, and each solution was prepared by using a polyethylene terephthalate film (Toray ( Co., Ltd., registered trademark Lumirror) so that the film thickness after drying is 50 μm,
It was dried and coated with a polyethylene film having a thickness of 35 μm to obtain a photosensitive element.

[0028]

[Table 1]

In Table 1, APG-400 means polypropylene glycol diacrylate manufactured by Shin-Nakamura Chemical Co., Ltd., and ethylenically unsaturated compounds a to j have the symbols in the general formula (I) shown in Table 2. Means a compound.

[0030]

[Table 2]

The following test was conducted on each of the obtained photosensitive elements, and the obtained results are shown in Table 5. In these tests, the lamination of the photosensitive element was performed at a substrate temperature of 25 ° C., a lamination temperature of 110 ° C., a lamination pressure (air cylinder pressure of a laminator) of 3.5 kg / c.
m ² and the laminating speed of 1.5 m / min.

(1) Plating resistance The obtained photosensitive element was laminated on a substrate under the above conditions, a negative film was applied, and a high pressure mercury lamp of 3 kW (HMW-201B, manufactured by Oak Manufacturing Co., Ltd.) was used to obtain 60 mJ. / Cm
² exposures were made. At this time, so that the light sensitivity can be evaluated,
A negative film (21-step step tablet in which the optical density is 0.05 for the first step and the optical density is increased by 0.15 for each step) is formed so that the amount of light transmission decreases stepwise. . The light sensitivity is indicated by the number of steps of the step tablet, and the higher the number of steps of this step tablet, the higher the light sensitivity.

Next, after removing the PET and developing the product, it was degreased, washed with running water for 1 minute, and then immersed in a 10/20% by volume aqueous solution of hydrogen peroxide / sulfuric acid for 2 minutes. Further, after rinsing with running water for 1 minute, it was immersed in a 10% sulfuric acid aqueous solution bath for 1 minute and again rinsing with running water for 1 minute. Then, copper sulfate plating bath [copper sulfate 75 g / 1, sulfuric acid 190
g / 1, chloride ion 75ppm, copper greem PCM
(Manufactured by Meltex Co., trade name) 5 ml / l] and subjected to copper sulfate plating bath 25 ° C., 3 A / dm ² for 40 minutes.
Immediately after the completion of copper sulfate plating, the plate is washed with water, and then immersed in a 10% aqueous solution of borofluoric acid for 1 minute, and then solder plating bath [45% tin borofluoride 64 ml / l, 45% lead borofluoride 22 ml / l. , 42% borofluoric acid 200
ml / l, Pultin LA Conductivity Salt (Meltex's trade name) 20 g / l, Pultin LA
40 ml / l of a starter (trade name of Meltex Co.)], and performed at 25 ° C. and 2 A / dm ² for 20 minutes. After the solder plating was completed, it was washed with water and dried.

In order to check the plating resistance, a cellophane tape was immediately applied after drying, and this was peeled in the vertical direction, and the presence or absence of peeling of the resist was examined (tape test). After that, the presence or absence of chipping of the solder plating was observed with an optical microscope from above. When the solder plating is removed, it is observed under the transparent resist. The results are shown in Table 5 below.

(2) Peelability The obtained photosensitive element was laminated on the substrate under the above conditions, and a negative film having a rectangular opening (light transmitting portion) of 5 cm × 7 cm was applied. It was exposed and developed with an exposure amount such that it becomes 8 steps with a step tablet. Next, the developed sample is immersed in a beaker containing a 3% aqueous sodium hydroxide solution at 50 ° C., the resist (photo-cured coating) is peeled off, and the size of the peeled piece and the peeling time (second) are measured, The results are shown in Table 5 below. The size of the peeled piece was evaluated according to the criteria shown in Table 3.

[0036]

[Table 3]

(3) Cross-Cut Property The obtained photosensitive element was laminated on the substrate under the above conditions, exposed and developed in the same manner as in (2). Then
The cross-cut property was evaluated by the method of JIS-K5400, and the results are shown in Table 5 below. The evaluation was performed according to the criteria shown in Table 4.

[0038]

[Table 4] The one having a high evaluation score of cross-cut property has excellent flexibility and adhesion. (4) Resist shape The obtained photosensitive element was laminated on the base material under the above-mentioned conditions, exposed with an exposure amount such that a 21-step tablet has 8 steps, and then developed and developed to 120 μm / 120 μm = line / A space resist pattern was obtained. The shape of the resist was observed and evaluated with a scanning electron microscope (S-2100A, manufactured by Hitachi, Ltd.). It was evaluated whether or not the line shape had irregularities, and the results are shown in Table 5 below. The evaluation was performed according to the following criteria. ○ Line shape has no irregularities × Line shape has irregularities (5) Scum occurrence Only 0.2 m ² of the photosensitive layer of the obtained element is taken out, added to a 1 wt% sodium carbonate aqueous solution, and stirred at room temperature for 2 hours with a stirrer. did. A predetermined amount of nonionic antifoaming agent was added to the obtained emulsion so as to be 0.1% by weight,
The mixture was further stirred for 10 minutes and left standing overnight. Then, the presence or absence of scum was observed.

[0039]

[Table 5]

[0040]

INDUSTRIAL APPLICABILITY The photosensitive resin composition of the present invention has good adhesion to the underlying metal (copper foil), is excellent in plating resistance, flexibility, resist shape and peeling property, etc. No scum is generated.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location G03F 7/033 H01L 21/027 H05K 3/18 D 7511-4E (72) Inventor Kazutaka Masaoka Ibaraki Ibaraki 4-13-1, Higashimachi, Hitachi, Ltd. Yamazaki Plant, Hitachi Chemical Co., Ltd. (72) Inventor Tatsuya Ichikawa 4-13-1, Higashimachi, Hitachi City, Ibaraki Hitachi Chemical Co., Ltd. Yamazaki Plant (72) Inventor Masajiro Yano 14 Goi Minamikaigan, Ichihara City, Chiba Prefecture Goi Plant, Hitachi Chemical Co., Ltd. (72) Akihiro Kobayashi 14 Goi Minami Kaigan, Ichihara City, Chiba Prefecture Goi Factory, Hitachi Chemical Co., Ltd. (72) Invention Toshio Akima 14 Goi Minami Coast, Ichihara City, Chiba Prefecture Hitachi Chemical Co., Ltd. Goi Factory

Claims (5)

[Claims] 1. (A) General formula (I): [In the formula, R ₁ and R ₄ each independently represent a hydrogen atom or a methyl group, R ₂ represents an ethylene group or a propylene group, R ₃ represents an ethylene group or a propylene group, and R ₂ and the R ₃ an always different groups, when R ₂ is a propylene group and m is 1-2 integer, n is an integer of 1 or more, R ₃
Is a propylene group, n is an integer of 1 to 2 and m is an integer of 1 or more], (B) an organic halogen compound, (C) a film property imparting agent. A photosensitive resin composition comprising a polymer and (D) a photoinitiator capable of generating free radicals by actinic radiation and / or a photoinitiator system. 2. The composition according to claim 1, which contains 5 to 60% by weight of the ethylenically unsaturated compound represented by the general formula (I) as the component (A), relative to the film-forming polymer as the component (C). The photosensitive resin composition of. 3. The photosensitive resin composition according to claim 1, wherein the organic halogen compound as the component (B) is an organic halogen compound having a tribromomethyl group. 4. A photosensitive element comprising a layer of the photosensitive resin composition according to claim 1, 2 or 3 and a support film supporting the layer. 5. The photosensitive element according to claim 4, wherein a peelable cover film is laminated on a layer of the photosensitive resin composition.