JP2003248320A - Photosensitive element, method for producing resist pattern using the same, method for producing printed circuit board and method for producing lead frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive element which can be laminated in a good yield and is very excellent in peeling characteristics, laminating property, shelf stability and working property and to provide a method for producing a resist pattern and a method for producing a printed circuit board or a lead frame with the resist pattern. <P>SOLUTION: In the photosensitive element consisting of a supporting film (a), a photosensitive resin composition layer (b) and a protective film (c), the layer (b) contains (A) a binder polymer having a weight average molecular weight of 20,000-200,000, (B) a photopolymerizable compound in which the concentration of polymerizable ethylenically unsaturated groups is 0.12-0.26 mol per 100 g, in total, of the components (A) and (B), and (C) a photopolymerization initiator, and the number of fish eyes of ≥80 μm diameter contained in the protective film (c) is ≤5 per 1 m<SP>2</SP>. The element is laminated on a substrate for forming a circuit in such a way that the layer (b) adheres to the substrate and exposure is carried out. The exposed part is photoset and the unexposed part is removed by development. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive element, a resist pattern manufacturing method using the same, a printed wiring board manufacturing method and a lead frame manufacturing method.

[0002]

2. Description of the Related Art In recent years, with the trend toward lighter, thinner, shorter, smaller semiconductor devices and a smaller number of products, the number of lead frames used for mounting IC chips on a printed circuit board is rapidly increasing. . There are stamping method and etching method as the lead frame manufacturing method, but it is difficult to manufacture narrow products due to miniaturization with the stamping method, and the die cost becomes expensive due to the small quantity and variety of products. An etching method that can manufacture small products and does not require a mold is advantageous for multi-product production. The photosensitive resin composition used in the etching method includes a water-soluble liquid photosensitive resin composition, a solvent-containing liquid photosensitive resin composition, a photosensitive element and the like. When using a liquid photosensitive resin in the photosensitive resin composition,
A huge investment is required for the coating device, it takes a lot of time to coat, and the photosensitive resin composition and the common usable period after coating the photosensitive resin composition are short and low in sensitivity. There are drawbacks. Further, since the water-soluble photosensitive resin composition contains a harmful chromate, there is a problem that the waste liquid treatment process becomes complicated. Further, the solvent-containing liquid photosensitive resin composition has a problem that it adversely affects the human body and the environment because it discharges the organic solvent during coating.

On the other hand, the photosensitive element has a sandwich structure in which a photosensitive resin composition is applied on a transparent support film, dried, and a protective film is attached thereto, and a photosensitive resin composition layer is formed on a metal substrate. Is completed by heating and pressure-bonding the photosensitive resin composition layer while removing the protective film, so that compared to the liquid photosensitive resin composition, less capital investment, high sensitivity, long life etc. It has features and excels in precision metal workability. In addition, the lead frame I
An increasing number of products have dimples formed on the C chip mounting portion to improve the heat dissipation effect. For this product, the releasability after metal etching is important for the characteristics required for the photosensitive resin composition layer. Due to the change in the dimple diameter, the resist enters the dimples and remains unpeeled, resulting in a defect.

On the other hand, a polyester film such as a polyethylene terephthalate film is used as the supporting film of the photosensitive element, and a polyolefin film such as a polyethylene film is used as the protective film. A polyolefin film usually used as a protective film is produced by melting raw materials by heat, kneading, extruding, biaxially stretching, casting or inflation method. Generally, a protective film such as a polyolefin film contains a foreign substance called a fisheye 4, an undissolved substance and a thermally deteriorated substance as shown in FIG. The size of fish eyes is generally 10 μm in diameter.
It is ~ 1 mm and protrudes from the film surface at a height of 1-50 µm. The convex portion of the fish eye causes a depression in the photosensitive resin composition layer, and an air void 6 is generated on the substrate after lamination. That is, the protective film 3 having the support film 1, the photosensitive resin composition layer 2, and the fish eyes 4.
When the photosensitive element made of is peeled off the protective film 3 and laminated on the substrate 5, an air void 6 is generated. The air voids 6 correlate with the film thickness of the photosensitive resin composition layer 2, and are more likely to occur as the film thickness of the photosensitive resin composition layer 2 becomes thinner. In the next step of forming a resist image for exposure and development, a pattern is formed. Chips and disconnections occur. This phenomenon is
In the case of the etching method, the circuit pattern may be chipped or broken, and in the case of the plating method, it may cause a short circuit. Therefore, in order to prevent air entrapment in the photosensitive resin composition layer portion recessed by the fish eyes 4 during lamination, the photosensitive resin composition layer must flow by heat and pressure.

As a countermeasure against the air voids, Japanese Patent Publication No. 3-12402 discloses that a surface smoothing film having releasability is used as a protective film. Also,
JP-B-53-31670, JP-A-51-6370
No. 2, JP-A-1-314144 and the like disclose a method of laminating under a vacuum as a measure against air voids, but this method is larger in apparatus than the atmospheric pressure laminating method, and laminating is performed. Since the inside of the chamber is evacuated, there is a problem that foreign matter enters through minute gaps such as the metal base material input part and the unloading part, which lowers the environmental cleanliness.

[0006]

[Patent Document 1] Japanese Patent Publication No. 3-12402

[0007]

[Patent Document 2] Japanese Patent Publication No. 53-31670

[0008]

[Patent Document 3] JP-A-51-63702

[0009]

[Patent Document 4] Japanese Patent Laid-Open No. 1-314144

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a photosensitive element which can be laminated with high yield because the number of air voids is reduced and which is extremely excellent in peeling property, laminating property, storage stability and workability. It is provided. Another aspect of the present invention is that the number of air voids is reduced, which is extremely useful for increasing the number of pins in a lead frame or BGA, making them narrower, and increasing the density of printed wiring on which these semiconductor packages are mounted. Can
The present invention also provides a method for producing a resist pattern having excellent peeling properties, laminating properties, storage stability and workability. Still another embodiment of the present invention is extremely useful for increasing the number of pins in a lead frame or BGA, narrowing the size, and increasing the density of printed wiring on which these semiconductor packages are mounted. Since the number of air voids generated is reduced, they are stacked with high yield. It is intended to provide a method for producing a printed wiring board or a lead frame having a resist pattern which is capable of achieving excellent release characteristics, laminating properties, storage stability and workability.

[0011]

The present invention provides a photosensitive element comprising a support film (a), a photosensitive resin composition layer (b) and a protective film (c), which is a photosensitive resin composition layer (b). , (A) binder polymer, (B)
The concentration of the polymerizable ethylenically unsaturated group is 0.12 to 0. 0, based on 100 g of the total amount of the components (A) and (B).
When the number of fish eyes having a diameter of 80 μm or more contained in the protective film (c) is 5 / m ² or less, the number of fish eyes is 26 mol, and the photopolymerizable compound (C) is contained in the protective film (c). One photosensitive element. Another aspect of the present invention is to laminate the photosensitive element according to the present invention on a circuit-forming substrate so that the photosensitive resin composition layer is in intimate contact, irradiate actinic rays imagewise, and expose the exposed portion to light. The present invention relates to a method for producing a resist pattern, which comprises curing and removing an unexposed portion by development. Still another aspect of the present invention relates to a method for producing a printed wiring board or a lead frame, which comprises etching or plating a circuit forming substrate having a resist pattern produced by the method for producing a resist pattern according to the present invention.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The supporting film (a) in the present invention includes, for example, a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, polyester, etc., and from the viewpoint of transparency. It is preferable to use a polyethylene terephthalate film. Moreover, what is available is, for example, Tetron film GS manufactured by Teijin Ltd.
Examples thereof include polyester films such as the series and Mylar film D series manufactured by DuPont. The thickness of the support film is preferably 1 to 100 μm, and 12
More preferably, it is -25 μm. This film thickness is 1μ
If it is less than m, the mechanical strength tends to be low, so that problems such as tearing of the supporting film during coating tend to occur, and 10
If it exceeds 0 μm, the resolution tends to decrease and the cost tends to increase. Since these support films must be removable from the photosensitive resin composition layer later, they must not be surface-treated or made of a material that makes them impossible to remove. .

Photosensitive resin composition layer (b) in the present invention
The photosensitive resin composition of (A) is a binder polymer,
(B) The concentration of the polymerizable ethylenically unsaturated group is (A)
0.12 per 100 g of the total amount of the component and the component (B)
To 0.26 mol of the photopolymerizable compound and (C) the photopolymerization initiator.

As the above-mentioned (A) binder polymer,
Examples thereof include acrylic resin, styrene resin, epoxy resin, amide resin, amide epoxy resin, alkyd resin, and phenol resin. From the viewpoint of alkali developability, acrylic resins are preferred. These may be used alone or in combination of two or more.

The (A) binder polymer is
For example, it can be produced by radically polymerizing a polymerizable monomer. Examples of the polymerizable monomer include styrene, vinyltoluene, a polymerizable styrene derivative substituted at the α-position or an aromatic ring such as α-methylstyrene, acrylamide such as diacetone acrylamide, acrylonitrile, and vinyl. -N-butyl ether and other vinyl alcohol esters, acrylic acid alkyl esters, methacrylic acid alkyl esters, acrylic acid tetrahydrofurfuryl ester, methacrylic acid tetrahydrofurfuryl ester, acrylic acid dimethylaminoethyl ester, methacrylic acid dimethylaminoethyl ester, Acrylic acid diethylaminoethyl ester, methacrylic acid diethylaminoethyl ester, acrylic acid glycidyl ester, methacrylic acid glycidyl ester, 2,2,2-trifluoro Ethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, acrylic acid, methacrylic acid, α-bromoacryl Acid, α-chloroacrylic acid, β-furylacrylic acid, β-styrylacrylic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, maleic acid monoesters such as monoisopropyl maleate, fumaric acid, Cinnamic acid, α-cyanocinnamic acid,
Examples thereof include itaconic acid, crotonic acid, and propiolic acid.

The above-mentioned acrylic acid alkyl ester or methacrylic acid alkyl ester is, for example, one represented by the general formula (I)

[Chemical 1] (In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 12 carbon atoms), the alkyl group of these compounds has a hydroxyl group, an epoxy group, a halogen group, etc. And the like. Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² in the general formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group,
Examples include octyl group, nonyl group, decyl group, undecyl group, dodecyl group and structural isomers thereof.

Examples of the monomer represented by the above general formula (I) include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid propyl ester, acrylic acid butyl ester, acrylic acid pentyl ester, and acrylic acid hexyl ester. , Acrylic acid heptyl ester, acrylic acid octyl ester, acrylic acid 2-ethylhexyl ester, acrylic acid nonyl ester, acrylic acid decyl ester, acrylic acid undecyl ester, acrylic acid dodecyl ester, methacrylic acid methyl ester, methacrylic acid ethyl ester, methacrylic acid Acid propyl ester, methacrylic acid butyl ester, methacrylic acid pentyl ester, methacrylic acid hexyl ester, methacrylic acid heptyl ester, methacrylic acid octyl ester, meta Acrylic acid 2-ethylhexyl ester, methacrylic acid nonyl ester, decyl methacrylate esters, methacrylic acid undecyl ester, and methacrylic acid dodecyl ester. These may be used alone or in combination of two or more.

Further, the (A) binder polymer is
From the viewpoint of alkali developability, it is preferable to contain a carboxyl group, and for example, it can be produced by radical polymerization of a polymerizable monomer having a carboxyl group and another polymerizable monomer. When the binder polymer (A) contains a carboxyl group, acrylic acid or methacrylic acid is preferably contained in an amount of 12 to 40% by weight, and preferably 15 to 25% by weight, from the viewpoint of alkali developability and alkali resistance. More preferable. If the content is less than 12% by weight, the alkali developability tends to be poor, and if it exceeds 40% by weight, the alkali resistance tends to be poor. In addition, it is preferable that the binder polymer (A) contains styrene or a styrene derivative as a polymerizable monomer from the viewpoint of flexibility. These binder polymers are used alone or in combination of two or more.

The polymer of the component (A) in the present invention has a weight average molecular weight of 20,000 to 200,000.
Is preferred and 40,000 to 120,000
Is more preferable. This weight average molecular weight is 2
If it is less than 10,000, the developing solution resistance and film strength tend to decrease, and if it exceeds 200,000, the resolution tends to decrease. The weight average molecular weight is measured by a gel permeation chromatography method and converted by a calibration curve prepared using standard polystyrene. The acid value of the (A) binder polymer is preferably 80 to 300 mgKOH / g.
More preferably, it is 0 to 200 mgKOH / g. If the acid value is less than 80, the developability tends to deteriorate, and
If it exceeds, the chemical resistance tends to deteriorate.

The concentration of the polymerizable ethylenically unsaturated group in the photopolymerizable compound (B) is 0.12 to 0.26 mol based on 100 g of the total amount of the components (A) and (B). It is necessary that it is 0.14 to 0.25 mol, more preferably 0.18 to 0.23 mol. If this concentration is less than 0.12 mol, a peeling residue that is not easy to remove occurs in a product that requires creation of a through hole having a small diameter (diameter of 50 to 300 μm) or a half-etched portion during metal etching. When it exceeds 0.26 mol, the peeling time becomes long and the peeling remains or becomes impossible to peel, which has a great influence on the manufacturing time and the manufacturing apparatus. The concentration of the polymerizable ethylenically unsaturated group can be calculated from the following relational expression (1).

[0021]

[Equation 1]

Examples of the photopolymerizable compound (B) include polyhydric alcohols, compounds obtained by reacting polyhydric alcohols with α, β-unsaturated carboxylic acids, and 2,2-bis (4- (acryl). Roxypolyethoxy) phenyl) propane, 2,2-bis (4- (methacryloxypolyethoxy) phenyl) propane, a compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid, a urethane monomer, Nonylphenyl dioxylene acrylate, nonyl phenyl dioxylene methacrylate, γ-chloro-β-hydroxypropyl-β′-acryloyloxyethyl-o-phthalate, γ-chloro-
β-hydroxypropyl-β′-methacryloyloxyethyl-o-phthalate, β-hydroxyethyl-β ′
-Acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-methacryloyloxyethyl-
o-phthalate, β-hydroxypropyl-β′-acryloyloxyethyl-o-phthalate, β-hydroxypropyl-β′-methacryloyloxyethyl-o-
Examples thereof include phthalate, acrylic acid alkyl ester, and methacrylic acid alkyl ester.

Examples of the compound obtained by reacting the above polyhydric alcohol with α, β-unsaturated carboxylic acid include:
Polyethylene glycol diacrylate having 2 to 14 ethylene groups, polyethylene glycol dimethacrylate having 2 to 14 ethylene groups, polypropylene glycol diacrylate having 2 to 14 propylene groups, and propylene groups 2 to 14 polypropylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethoxytriacrylate, trimethylolpropane ethoxytrimethacrylate, trimethylol Propane diethoxy triacrylate, trimethylol propane diethoxy trimethacrylate, trimethylol propane Reethoxytriacrylate, trimethylolpropane triethoxytrimethacrylate, trimethylolpropane tetraethoxytriacrylate, trimethylolpropane tetraethoxytrimethacrylate, trimethylolpropane pentaethoxytriacrylate, trimethylolpropane pentaethoxytrimethacrylate, tetramethylolmethanetriacrylate , Tetramethylol methane trimethacrylate, tetramethylol methane tetraacrylate, tetramethylol methane tetramethacrylate, polypropylene glycol diacrylate having 2 to 14 propylene groups, polypropylene glycol dimethacrylate having 2 to 14 propylene groups, di Pentaerythritol pentaacrylate, dipen Dipentaerythritol dimethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexa methacrylate.

As the above α, β-unsaturated carboxylic acid,
For example, acrylic acid and methacrylic acid can be used. Examples of 2,2-bis (4- (acryloxypolyethoxy) phenyl) propane include 2,2-bis (4
-(Acryloxydiethoxy) phenyl) propane,
2,2-bis (4- (acryloxytriethoxy) phenyl) propane, 2,2-bis (4- (acryloxypentaethoxy) phenyl) propane, 2,2-bis (4
-(Acryloxydecaethoxy) phenyl) and the like. Examples of the 2,2-bis (4- (methacryloxypolyethoxy) phenyl) propane include 2,2
-Bis (4- (methacryloxydiethoxy) phenyl)
Propane, 2,2-bis (4- (methacryloxytriethoxy) phenyl) propane, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane,
2,2-bis (4- (methacryloxydecaethoxy) phenyl) propane and the like, and 2,2-bis (4-
(Methacryloxypentaethoxy) phenyl) propane is BPE-500 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.)
Is commercially available as.

Examples of the glycidyl group-containing compound include trimethylolpropane triglycidyl ether triacrylate, trimethylolpropane triglycidyl ether trimethacrylate, and 2,2-bis (4-).
Acryloxy-2-hydroxy-propyloxy) phenyl, 2,2-bis (4-methacryloxy-2-hydroxy-propyloxy) phenyl and the like can be used. Examples of the urethane monomer include an acrylic monomer having an OH group at the β-position or a corresponding methacrylic monomer and isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Addition reaction product, tris (methacryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane dimethacrylate, EO, PO-modified urethane dimethacrylate, and the like. In addition, E
O represents ethylene oxide, and the EO-modified compound has an ethylene oxide group block structure. Further, PO represents propylene oxide, and the PO-modified compound has a block structure of propylene oxide group.

Examples of the acrylic acid alkyl ester include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid butyl ester, acrylic acid 2-ethylhexyl ester and the like. Examples of the methacrylic acid alkyl ester include methacrylic acid methyl ester, methacrylic acid ethyl ester, methacrylic acid butyl ester, and methacrylic acid 2-ethylhexyl ester. These alone or 2
Used in combination with more than one type.

Examples of the photopolymerization initiator (C) include benzophenone, N, N'-tetramethyl-4,
4'-diaminobenzophenone (Michler's ketone),
N, N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4
-Morpholinophenyl) -butanone-1,2-methyl-
Aromatic ketones such as 1- [4- (methylthio) phenyl] -2-morpholino-propanone-1, 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone,
1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2
-Methylanthraquinone, 1,4-naphthoquinone, 9,
Quinones such as 10-phenantharaquinone, 2-methyl 1,4-naphthoquinone and 2,3-dimethylanthraquinone, benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether and other benzoin ether compounds, benzoin, methylbenzoin, ethylbenzoin Benzoin compounds such as benzyl dimethyl ketal, benzyl derivatives such as 2- (o-chlorophenyl)
-4,5-diphenylimidazole dimer, 2- (o-
Chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl)-
2,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, etc. 2,4,5-triarylimidazole dimers such as 4,4,5-triarylimidazole dimers, acridine derivatives such as 9-phenylacridine and 1,7-bis (9,9′-acridinyl) heptane, Examples include N-phenylglycine and coumarin compounds.

Also, a thioxanthone compound and a tertiary amine compound may be combined, such as a combination of diethylthioxanthone and dimethylaminobenzoic acid.
From the viewpoint of adhesion and sensitivity, 2,4,5-triarylimidazole dimer is more preferable. These are used alone or in combination of two or more.

The blending amount of the component (A) is 40-80 with respect to 100 parts by weight of the total amount of the components (A) and (B).
The amount is preferably 50 parts by weight, and more preferably 50 to 70 parts by weight. If the amount is less than 40 parts by weight, the photocured product tends to be brittle and the coating property tends to be poor, and if it exceeds 80 parts by weight, the sensitivity tends to be insufficient.

The blending amount of the component (B) is 20 to 60 based on 100 parts by weight of the total amount of the components (A) and (B).
It is preferable to set it as a weight part, and it is more preferable to set it as 30 to 50 weight parts. If this 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 become brittle.

The blending amount of the component (C) is 0.1 to 2 with respect to 100 parts by weight of the total amount of the components (A) and (B).
The amount is preferably 0 part by weight, more preferably 0.2 to 10 parts by weight. If the blending amount is less than 0.1 parts by weight, the sensitivity tends to be insufficient, and if it exceeds 20 parts by weight, the absorption on the surface of the composition is increased during the exposure and the internal photocuring is unsuccessful. Tends to be enough.

In the photosensitive resin composition of the present invention, if necessary, a dye such as malachite green, a photocoloring agent such as tribromophenyl sulfone or leuco crystal violet, a thermal color-preventing agent, and p-toluene sulfone. (A) plasticizers such as amides, pigments, fillers, defoamers, flame retardants, stabilizers, adhesion promoters, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents, etc.
Each of the component and the component (C) may be contained in an amount of about 0.01 to 20 parts by weight based on 100 parts by weight. These are used alone or in combination of two or more.

The photosensitive resin composition of the present invention contains, if necessary, methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve,
It can be dissolved in a solvent such as toluene or N, N-dimethylformamide or a mixed solvent thereof to be applied as a solution having a solid content of about 30 to 60% by weight.

The photosensitive resin composition of the present invention is not particularly limited, but metal surfaces such as copper, copper-based alloys, iron-based alloys such as nickel, chromium, iron and stainless steel, preferably copper and copper-based alloys. It is preferable that the composition is applied as a liquid resist on the surface of the iron-based alloy, dried, and then coated with a protective film if necessary, or used in the form of a photosensitive element.

The thickness of the photosensitive resin composition layer (b) is from 1 to
The thickness is preferably 50 μm, more preferably 5 to 30 μm, and even more preferably 10 to 25 μm. If the thickness is less than 1 μm, the follow-up property tends to deteriorate, chipping and disconnection tend to occur, and if it exceeds 50 μm, the resolution tends to deteriorate.

The viscosity of the photosensitive resin composition layer (b) at 30 ° C. is preferably 15 to 50 Mpa · s, and 25
More preferably, it is -40 Mpa · s. Viscosity is 15Mp
If it is less than a · s, the resin called edge fusion tends to exude from the edges of the photosensitive element, and
If it exceeds a · s, the resin flow becomes low, and air voids tend to occur. The measurement of the viscosity in the present invention is carried out by the following relational expression (2) with respect to Newtonian fluid.
Can be obtained by plotting t against 1 / Z ⁴ and using its slope. These measurements can be measured using a TMA device.

[0037]

[Equation 2]

In the protective film (c) of the present invention, the number of fish eyes having a diameter of 80 μm or more contained in the protective film (c) needs to be 5 / m ² or less. Further, as the surface roughness of the protective film (c), the center line average roughness Ra is preferably 0.005 to 0.05 μm, and more preferably 0.01 to 0.03 μm. The fisheye is a material in which foreign materials, undissolved materials, oxidative degradation materials, etc. are incorporated into the film when the material is heat-melted, kneaded, and extruded or stretched or a film is produced by a casting method. . The surface roughness in the present invention represents the surface roughness according to JIS B0601. Further, Ra in the present invention represents the center line average roughness, and Rmax represents the maximum height.

As described above, a film having a good fish eye level can be produced by selecting materials, optimizing the kneading method, and filtering after melting the materials. The size of the fisheye diameter is about 10 μm to 1 mm, depending on the material, and the height from the film surface is about 1 μm.
μm to 50 μm. Here, the fish eye size can be measured using, for example, an optical microscope, a contact surface roughness meter, a non-contact surface measuring instrument using a laser beam, a scanning electron microscope, or the like. The diameter of the fish eye in the present invention means the maximum diameter of the fish eye.

The thickness of the protective film (c) is 1 to 100 μm.
m is preferable, 5 to 50 μm is more preferable, and 15 to 50 μm is particularly preferable. When the thickness is less than 1 μm, the strength of the protective film is insufficient, and therefore, when the protective film is attached to the photosensitive resin composition layer, the protective film tends to be easily broken. Wrinkles tend to occur when laminating.

Such a protective film is commercially available, for example, Alfan MA-410 manufactured by Oji Paper Co., Ltd.,
Examples thereof include, but are not limited to, E-200C, polypropylene film manufactured by Shin-Etsu Film Co., Ltd., and polyethylene terephthalate film such as PS series manufactured by Teijin Limited PS-25. In addition, it is possible to easily manufacture a commercially available film by sandblasting.

The adhesive strength between the photosensitive resin composition layer (b) and the support film (a) may be greater than the adhesive strength between the photosensitive resin composition layer (b) and the protective film (c). preferable. The adhesive strength between the photosensitive resin composition layer (b) and the supporting film (a) is determined by the photosensitive resin composition layer (b).
When the adhesive strength between the protective film and the protective film (c) is smaller than the adhesive strength, the photosensitive resin composition layer tends to be transferred to the protective film side when the protective film is removed during lamination.

In the photosensitive element of the present invention, for example, the above-mentioned photosensitive resin composition is applied on a support film, dried,
It is obtained by laminating a protective film.

When a resist pattern is produced using the photosensitive element of the present invention, for example, after removing the protective film, the photosensitive resin composition layer is laminated by heating and pressing the photosensitive resin composition layer onto the circuit-forming substrate. And so on. The surface to be laminated is usually a metal surface, but there is no particular limitation. The heating temperature of the photosensitive resin composition layer is 90 to 1
The temperature is preferably 30 ° C., and the pressure bonding is 0.1 to
The pressure is preferably 1.0 MPa (1 to 10 kg / cm ² ), but these conditions are not particularly limited. Further, if the photosensitive resin composition layer is heated to 90 to 130 ° C. as described above, it is not necessary to preheat the circuit forming substrate in advance, but in order to further improve the laminate property, It is also possible to preheat the substrate.

The photosensitive resin composition layer thus laminated is irradiated with actinic rays imagewise through a negative or positive mask pattern called an artwork. At this time, when the polymer film present on the photosensitive resin composition layer is transparent, it may be irradiated with actinic rays as it is, and when it is opaque, it is of course necessary to remove it. From the viewpoint of protecting the photosensitive resin composition layer, it is preferable that the polymer film is transparent and the actinic ray is irradiated through the polymer film while the polymer film remains. As the light source of the actinic ray, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a xenon lamp that effectively emits ultraviolet rays is used. In addition, a flood light bulb for photography, a solar lamp or the like that effectively radiates visible light is also used.

Then, after the exposure, if the support is present on the photosensitive resin composition layer, after removing the support,
A resist pattern is manufactured by using a developer such as an alkaline aqueous solution to remove the unexposed portion and develop it by a known method such as spraying, rocking dipping, brushing, scraping or the like. As the developer, a safe and stable developer having good operability such as an alkaline aqueous solution is used. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxides, alkali carbonates such as lithium, sodium, potassium or ammonium carbonates or bicarbonates, potassium phosphate, phosphoric acid. Alkali metal phosphates such as sodium, sodium pyrophosphate, alkali metal pyrophosphates such as potassium pyrophosphate, and the like are used.

The alkaline aqueous solution used for development is a dilute solution of 0.1 to 5% by weight sodium carbonate,
0.1-5 wt% dilute potassium carbonate solution, 0.1-5
Dilute solution of sodium hydroxide by weight, 0.1-5% by weight
A dilute solution of sodium tetraborate is preferred. The pH of the alkaline aqueous 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 resin composition layer. Further, a surface active agent, a defoaming agent, a small amount of an organic solvent for accelerating development may be mixed in the alkaline aqueous solution. Development methods include a dip method and a spray method, and the high pressure spray method is most suitable for improving the resolution.

As the processing after the development, if necessary, 80 to
The resist pattern may be further cured and used by heating at about 250 ° C. or exposure at about 0.2 to 5 mJ / cm ² .

A cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or a hydrogen peroxide-based etching solution can be used for etching the metal surface after the development, but it is preferable to use a chloride solution because of its good etching factor. It is desirable to use a ferric solution.

When a printed wiring board or lead frame is manufactured using the photosensitive element of the present invention, the surface of the circuit-forming board is treated by a known method such as etching or plating using the developed resist pattern as a mask. .
Examples of the plating method include copper sulfate plating, copper plating such as copper pyrophosphate, solder plating such as high-throw solder plating, Watts bath (nickel sulfate-nickel chloride) plating, nickel plating such as nickel sulfamate plating, and hard plating. There are gold plating such as gold plating and soft gold plating. Then, the resist pattern is usually stripped with an aqueous solution having a stronger alkaline property than the alkaline solution used for the development. Examples of the strongly alkaline aqueous solution include 1 to 5 wt% sodium hydroxide aqueous solution, 1
A ~ 5 wt% potassium hydroxide aqueous solution or the like is used. Also, the printed wiring board on which the resist pattern is formed is
It may be a multilayer printed wiring board.

Further, the photosensitive element of the present invention is suitable as a photosensitive element for metal etching processing used for manufacturing lead frames, metal masks and the like.

[0052]

EXAMPLES The present invention will be described in detail below based on examples. Examples 1 to 3 and Comparative Examples 1 to 2 Components (A), (B), (C) and other components shown in Table 1 were mixed to prepare a solution of a photosensitive resin composition.

[0053]

[Table 1]

Next, 16 parts of this photosensitive resin composition solution was added.
It was evenly coated on a polyethylene terephthalate film having a thickness of μm and dried by a hot air convection dryer at 100 ° C. for about 5 minutes, and each protective film shown in Table 2 was laminated to obtain a photosensitive element. The film thickness of the photosensitive resin composition layer after drying was 17 μm. Table 2 shows the results of calculating the concentration of the polymerizable ethylenically unsaturated group of the photopolymerizable compound (B) of the photosensitive element produced above from the above relational expression (1).

Next, the thickness is 0.15 mm and the thickness is 20 × 20 cm.
Corner Copper Alloy (Yamaha Orin Metal Co., Ltd .: MP-702)
5) in a 3% by weight aqueous sodium hydroxide solution at 50 ° C.
Immersion for 1 minute, then 1 minute by volume of hydrochloric acid aqueous solution at 25 ° C for 1 minute, followed by washing with water and drying, while removing the protective film of the photosensitive element on the obtained substrate, roll temperature: 110 ° C, pressure : 0.4 MPa, speed: 2 m / min. Then, the substrate thus obtained was used for a 3 kW ultra-high pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd., HM
W-201GX) and exposed at 50 mJ / cm ² and 1 wt%
Was spray-developed for 30 seconds with an anhydrous sodium carbonate aqueous solution, washed with water and dried.

The exposed substrate was made 40 mm × 50 mm square, and the substrate was dipped in a 2 wt% sodium hydroxide aqueous solution at 50 ° C., and the time taken for the photosensitive resin composition layer to peel from the substrate was measured. It shows in Table 2.

During exposure, the substrate is made into a 50 mm × 100 mm square, and a half-etching negative is used to expose it under the above exposure conditions and develop under the above development conditions. Next, ferric chloride (45Be, free hydrochloric acid concentration 0.3%, ORP value 6
Etching is performed at 20 mV) and 50 ° C. for 300 seconds to form a half-etched portion having a minute diameter (100 to 300 μm) and a depth of 60 to 100 μm. Then, the photosensitive resin composition layer was peeled from the substrate having the half-etched portion prepared with a 2 wt% sodium hydroxide aqueous solution, spray-treated with 1 wt% sulfuric acid, washed with water and dried. The photosensitive resin composition remaining in the half-etched portion of the substrate (hereinafter, referred to as residual peeling) is measured with a stereoscopic microscope of 100 times. The results are shown in Table 2.

[0058]

[Table 2]

On the other hand, a copper alloy having a thickness of 0.15 mm and a size of 20 × 20 cm (Yamaha Ohrin Metal Co., Ltd .: MP-702).
5) in a 3% by weight aqueous sodium hydroxide solution at 50 ° C.
Immersion for 1 minute, then 1 minute by volume of hydrochloric acid aqueous solution at 25 ° C for 1 minute, followed by washing with water and drying, while removing the protective film of the photosensitive element on the obtained substrate, roll temperature: 110 ° C, pressure : 0.4 MPa, speed: 2 m / min. Then, the substrate thus obtained was used for a 3 kW ultra-high pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd., HM
W-201GX) was used for exposure at 50 mJ / cm ² .

The number of air voids on the substrate after exposure is 100
The measurement was performed using a double microscope. In addition, the size and number of fish eyes of each protective film were measured using a 100 × microscope. The results are summarized in Table 3.

[0061]

[Table 3]

As is clear from Table 3, when a film having a diameter of 80 μm or more and a number of fish eyes of 5 pieces / m ² or less is used as the protective film (c), air voids causing disconnection or chipping can be prevented. It can be seen that the number of occurrences decreases.

[0063]

EFFECT OF THE INVENTION The photosensitive element according to the present invention can be laminated with a good yield because the number of air voids is reduced, and is extremely excellent in peeling property, laminating property, storage stability and workability. The method of manufacturing a resist pattern according to the present invention is extremely useful for increasing the number of pins in a lead frame or BGA, making them narrower, and increasing the density of printed wiring on which these semiconductor packages are mounted. It can be laminated with high yield, and is excellent in peeling property, laminating property, storage stability and workability. The method of manufacturing a printed wiring board or a lead frame according to the present invention is extremely useful for increasing the number of pins in a lead frame or BGA, narrowing the density, and increasing the density of printed wiring on which these semiconductor packages are mounted. Is reduced, so that the product can be laminated with high yield, and the peeling property, laminating property, storage stability and workability are excellent.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating the generation of air voids.

[Explanation of symbols]

1 Support film 2 Photosensitive resin composition layer 3 protective film 4 fish eyes 5 substrates 6 air voids

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinji Takano             Hitachi, Ichiba, Ibaraki Prefecture             Seikou Co., Ltd. Yamazaki Office (72) Inventor Yudai Fukaya             Hitachi, Ichiba, Ibaraki Prefecture             Seikou Co., Ltd. Yamazaki Office F term (reference) 2H025 AA01 AA02 AB11 AB15 AC01                       AD01 BC13 BC42 BC65 BC81                       BC83 CB55 DA02 FA43                 5E339 BC02 BD06 BD08 BD11 BE13                       CC01 CC02 CD01 CE11 CE14                       CF16 CF17 CG04 DD04 GG01                       GG10                 5E343 BB23 BB24 BB44 CC63 DD32                       DD63 EE17 ER16 ER18 GG03

Claims (10)

[Claims] 1. A photosensitive element comprising a support film (a), a photosensitive resin composition layer (b) and a protective film (c), wherein the photosensitive resin composition layer (b) is (A) weight average molecular weight. Of the binder polymer having 20,000 to 200,000, the concentration of the polymerizable ethylenically unsaturated group (B) is 100 g of the total amount of the components (A) and (B).
Of the fish eyes having a diameter of 80 μm or more, which comprises 0.12 to 0.26 mol of a photopolymerizable compound and (C) a photopolymerization initiator, and is contained in the protective film (c). A photosensitive element having a number of 5 / m ² or less. 2. The photosensitive element according to claim 1, wherein the protective film (c) is a polypropylene film or a polyethylene terephthalate film. 3. The photosensitive element according to claim 1, wherein the concentration of the polymerizable ethylenically unsaturated group in the photopolymerizable compound (B) is 0.14 to 0.25 mol. 4. The photosensitive element according to claim 1, wherein the concentration of the polymerizable ethylenically unsaturated group in the photopolymerizable compound (B) is 0.18 to 0.23 mol. 5. The (B) photopolymerizable compound contains two or more compounds, at least one of which is 2,2-bis (4- (acryloxypolyethoxy) phenyl) propane or 2,2-bis. The photosensitive element according to claim 1, which is (4- (methacryloxypolyethoxy) phenyl) propane. 6. The photosensitive element according to claim 1, wherein the protective film (c) is removed when a circuit-forming substrate is laminated. 7. The photosensitive element according to claim 1, wherein the thickness of the photosensitive resin composition layer (b) is 1 to 50 μm. 8. The photosensitive element according to claim 1, wherein the thickness of the photosensitive resin composition layer (b) is 5 to 30 μm. 9. The photosensitive element according to claim 1 is laminated on a circuit-forming substrate so that the photosensitive resin composition layer is in intimate contact with the substrate, and the active ray is imagewise irradiated. Then, the exposed part is photo-cured, and the unexposed part is removed by development to produce a resist pattern. 10. A method of manufacturing a printed wiring board or a lead frame, which comprises etching or plating a circuit-forming substrate having a resist pattern manufactured by the method of manufacturing a resist pattern according to claim 9.