JP3437179B2 - Photosensitive resin composition and photosensitive element using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD 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. There 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 Unexamined Patent Publication No. 62-74912 discloses the following formula (II)

[Chemical 2] A photosensitive resin composition having improved resist releasability using an ethylenically unsaturated compound having three or more unsaturated groups in one molecule is disclosed (R ₁ , R ₂ and R). ₃ is H or CH ₃ , and n is an integer). However, R ₁ =
When an ethylenically unsaturated compound having a polyethylene glycol chain of R ₂ = H is used, the strippability is improved, but the shape of the resist is deteriorated, line creases are generated during etching, and the flexibility and resistance of the resist are increased. Plating property is not enough. In addition, R ₁ = H, R ₂ = CH ₃ or R ₁ =
When an ethylenically unsaturated compound having a polypropylene glycol chain of CH ₃ and R ₂ = H is used, it has good flexibility, but the sensitivity and tenting property are lowered, and it is easy to separate in an alkali developing solution. , Cause scum,
If it adheres to the substrate, it causes problems such as short circuit and disconnection.

[0006]

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 element using the same.

[0007]

The present invention solves the above problems by using an ethylenically unsaturated compound in which a polyethylene glycol chain and a polypropylene glycol chain are incorporated in one molecule.

That is, the present invention provides (A) general formula (I)

[Chemical 3] [In the formula, R ₁ represents 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 R ₃ are always different groups, m and n represent the number of repeating units and each is an integer of 1 or more], an ethylenically unsaturated compound having 3 or more unsaturated groups in one molecule, (B) an organohalogen compound, (C) a film Gender-imparting polymer and (D)
Photoinitiator capable of generating free radicals by actinic radiation and / or
It also relates to a photosensitive resin composition containing a photoinitiator system and a photosensitive element comprising a layer of the composition and a support film supporting the layer.

Next, the photosensitive resin composition of the present invention will be described in detail. First, in the ethylenically unsaturated compound as the component (A), R ₁ represents hydrogen or a methyl group in the general formula (I). Each of m and n is an integer of 1 or more, but the sum of m and n is preferably 2 to 10.
If the sum of m and n exceeds 10, the resist shape tends to be inferior. Incidentally, -R ₃ O-and in the general Formulas (I) -
The R ₂ O— groups do not necessarily have to be present in consecutive n and m consecutive positions, respectively. That is, they may exist at random or may exist in blocks.

The ethylenically unsaturated compound having three or more unsaturated groups represented by the general formula (I) in one molecule is:
For example, glyceryl polyethoxypolypropoxytri (meth) acrylate, trimethylolpropane polyethoxypolypropoxytri (meth) acrylate, pentaerythritol polyethoxypolypropoxytri (meth) acrylate, pentaerythritol polyethoxypolypropoxytetra (meth) acrylate, Trimethylolethane polyethoxy polypropoxytri (meth)
Acrylate, dipentaerythritol polyethoxypolypropoxytri (meth) acrylate, dipentaerythritol polyethoxypolypropoxytetra (meth)
Examples thereof include, but are not limited to, acrylate, dipentaerythritol polyethoxypolypropoxypenta (meth) acrylate, dipentaerythritol polyethoxypolypropoxyhexa (meth) acrylate, and the like. The ethylenically unsaturated compound as the component (A) can be used alone or in combination of two or more kinds.

In the photosensitive resin composition of the present invention,
The amount of the ethylenically unsaturated compound as the component (A) used is
10 to 8 based on 100 parts by weight of the total amount of the photosensitive resin composition
The amount is preferably 0 part by weight, more preferably 20 to 50 parts by weight. If the amount of the component (A) used is too small, the developer resistance tends to decrease, and if it is too large, the viscosity of the photosensitive resin composition decreases, and edge fusion tends to occur.

In the photosensitive resin composition of the present invention, (E) other ethylenically unsaturated compounds other than the ethylenically unsaturated compound having three or more unsaturated groups represented by the general formula (I) in one molecule. Compounds can be added. As the other ethylenically unsaturated compound (E), it is preferable to use an acrylate monomer or a methacrylate monomer from the viewpoint of high sensitivity. A compound obtained by reacting an acid, for example, polyethylene glycol di (meth) acrylate (having 2 to 14 ethylene groups), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tri Methylolpropane ethoxytri (meth) acrylate, trimethylolpropane propoxytri (meth) acrylate,
Tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (having 2 to 14 propylene groups), dipentaerythritol penta (meth) acrylate, dipentaerythritol Hexa (meth) acrylate, bisphenol A
Polyoxyethylene di (meth) acrylate, for example,
Bisphenol A dioxyethylene di (meth) acrylate, bisphenol A trioxyethylene di (meth) acrylate
A compound obtained by adding α, β-unsaturated carboxylic acid to a glycidyl group-containing compound such as acrylate and bisphenol A decaoxyethylene di (meth) acrylate,
For example, trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, and other polyvalent carboxylic acids such as phthalic anhydride and a substance having a hydroxyl group and an ethylenically unsaturated group, such as β-hydroxyethyl ( Esterification products with (meth) acrylate, etc., alkyl esters of acrylic acid or methacrylic acid, for example, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester,
(Meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylic acid ester, trimethylhexamethylene diisocyanate, cyclohexanedimethanol and 2-hydroxyethyl Examples thereof include urethane (meth) acrylates such as a reaction product with a (meth) acrylic acid ester.

(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. Of these,
An aliphatic halogen compound having a weak carbon-halogen bond strength,
Particularly, a compound in which two or more halogen atoms are bonded to the same carbon, especially an organic bromine compound is preferable. Organohalogen compounds having a tribromomethyl group give more favorable results.

The amount of the component (B) used is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the total amount of the photosensitive resin composition. . If the amount of the component (B) used is too small, the imaging property tends to deteriorate, and if it is too large, the tent strength tends to decrease.

The film property imparting polymer 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, dimethylaminoethyl acrylate and the like.

The amount of the 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.

There are no particular restrictions on the photoinitiator or photoinitiator system that produces free radicals by the actinic radiation as the component (D), 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 Thioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzyl, 2,4,5-triary
Examples thereof include rumidazole dimer (rophin dimer), acridine compound, and the like.
A combination of two or more species can be used.

The amount of 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.

The above components (A) to (D) and (E)
There are no particular restrictions on the mixing order of the components, the mixing method, and the like.
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 a Teflon (registered trademark) film or release paper is used. Of the heat-resistant film as a temporary support film, a layer of the photosensitive resin composition is formed thereon, and a film having low heat resistance or low solvent resistance is laminated on this layer to form a temporary support. The film may be peeled off 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,
There are Teflon films, surface-treated papers, etc., and when peeling the cover film, the adhesive force between the photosensitive resin composition layer and the cover film is stronger than the adhesive force between the photosensitive resin composition layer and the support film. Anything smaller is acceptable.

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, etc., but is usually 10 to 1
00 μm.

The photosensitive resin composition of the present invention is applied as a solution onto a substrate and dried, or after a layer of the photosensitive resin composition as a photosensitive element is laminated on the substrate, imagewise exposure is performed. , And a plating resist is manufactured by development.

The exposure and development processing can be performed 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, and examples thereof include 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, and the like. Can be mentioned. Particularly, an aqueous solution of sodium carbonate is preferable.

The alkali development of the resin composition of the present invention can be carried out at a developer temperature of 10 to 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, and the chemical resistance of the plating resist is improved.

Further, a solution of the photosensitive resin composition of the present invention is directly applied to a substrate by a method such as a dip coating method or a flow coating method, and after drying the solvent, a film which is transparent to active light such as a polyester film or the like After lamination, in the same manner as in the case of the photosensitive element described above, by imagewise exposure through a negative mask, developing, and more preferably by exposing to actinic light, a plating resist having excellent characteristics similar to the above can be obtained. Can be formed.

[0031]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Synthesis 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.
The temperature was raised to 85 ° C. and left for 1 hour. Then, 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 g of azobisisobutyronitrile were dissolved in 31.2 g of solution A. The solution was added dropwise over 4 hours for reaction.

Next, 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. The 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 3 Photosensitive resin composition solutions were prepared according to the formulations (units are parts by weight) shown in Table 1, and each solution was used to prepare a polyethylene terephthalate film (Toray ( Co., Ltd., registered trademark Lumirror) so that the film thickness after drying is 50 μm, and the coating is dried.
A photosensitive element was obtained by coating with a polyethylene film having a thickness of 35 μm. In Table 1, BPE-10 means bisphenol A polyoxyethylene dimethacrylate manufactured by Shin-Nakamura Chemical Co., Ltd., an ethylenically unsaturated compound a.
To i mean compounds in which the symbols in the general formula (I) represent those shown in Table 2.

[0035]

[Table 1]

[0036]

[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 elements was carried out under the conditions of 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 / cm ² , and a lamination speed of 1.5 m / min. went.

(1) Plating resistance The obtained photosensitive element was laminated on the 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 exposure was performed. At this time, in order to evaluate the photosensitivity, a negative film made so that the amount of light transmission gradually decreases (optical density 0.05 is set as the first step and the optical density is increased by 0.15 step by step). 21-step step tablet)
Was used. 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 wt% sulfuric acid aqueous solution bath for 1 minute, and again rinsing with running water for 1 minute. Next, copper sulphate plating bath [copper sulphate 75 g / l, sulfuric acid 190 g / 1, chloride ion 75 ppm, copper greeme P
CM (Meltex, product name) 5 ml / l],
The copper sulfate plating bath was performed at 25 ° C. and 3 A / dm ² for 40 minutes.
Immediately after completion of copper sulfate plating, the plate is washed with water and then immersed in a 10 wt% borofluoric acid aqueous solution bath for 1 minute, followed by solder plating bath [45 wt% tin borofluoride 64 ml / l, 45 wt%
Weight% lead borofluoride 22 ml / l, 42% by weight borofluoric acid 200 ml / l, Pultin LA conductivity salt (Meltex, trade name) 20 g / l, Pultin LA starter (Meltex, trade name) 40
ml / l], 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 examine the plating resistance, Cellotape (registered trademark) 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 base material 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 dipped in a beaker containing 50% by weight of 3% by weight sodium hydroxide aqueous solution, the resist (photo-cured film) is peeled off, the size of the peeled piece and the peeling time (second) are measured, and the result is shown. The results are shown in Table 5 below. The size of the peeled piece was evaluated according to the criteria shown in Table 3.

[0042]

[Table 3]

(3) Cross-Cutability The obtained photosensitive element was laminated on a 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. Those having a high evaluation score of cross-cut property are excellent in flexibility and adhesion.

[0044]

[Table 4]

(4) Resist shape The obtained photosensitive element was laminated on the base material under the above-mentioned conditions, exposed to an exposure amount of 8 steps with a 21-step tablet, and then developed to 120 μm / 120 μm. = A line / 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.

○ No unevenness in line shape × Unevenness in line shape (5) Scum occurrence Only 0.2 m ² of the photosensitive layer of the obtained element was taken out, added to a 1 wt% sodium carbonate aqueous solution, and stirred at room temperature. Stir for 2 hours. 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.

[0047]

[Table 5]

[0048]

The photosensitive resin composition of the present invention and the photosensitive element using the same have good adhesion to the underlying metal (copper foil), plating resistance, flexibility, resist shape and releasability. Etc., and no scum is generated in the developer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI H05K 3/06 H05K 3/06 J 3/18 3/18 D (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F 7/004-7/18

Claims (4)

(57) [Claims] 1. (A) General formula (I): [In the formula, R ₁ represents 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 R ₃ are always different groups, m and n represent the number of repeating units and each is an integer of 1 or more], an ethylenically unsaturated compound having 3 or more unsaturated groups in one molecule, (B) an organohalogen compound, (C) a film Gender-imparting polymer and (D)
Photoinitiator capable of generating free radicals by actinic radiation and / or
Alternatively, a photosensitive resin composition solution containing a photosensitive resin composition containing a photoinitiator system and a solvent. 2. An ethylenically unsaturated compound having (A) three or more unsaturated groups represented by the general formula (I) in one molecule is used in an amount of 10 parts by weight based on 100 parts by weight of the total amount of the photosensitive resin composition.
The photosensitive resin composition solution according to claim 1, which comprises -80 parts by weight. 3. A photosensitive element having a support film and a layer comprising the photosensitive resin composition solution according to claim 1. 4. The photosensitive element according to claim 3, wherein a peelable cover film is laminated on a layer made of a photosensitive resin composition solution.