JPH10186670A - Photosensitive resin composition and photosensitive film using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive resin compsn. having improved adhesion especially to an iron-contg. alloy and preventing an etching soln. from penetrating into the interface between resist and metal at the time of etching and to form a photosensitive film using the compsn. SOLUTION: This photosensitive resin compsn. developable with a dil. aq. alkali soln. and used for etching a metal contains a film property imparting polymer obtd. by copolymerizing a vinyl monomer with (meth)acrylic ester and (meth)acrylic acid as copolymerizable components, a photopolymn, initiator, an ethylenic unsatd. compd. represented by formula I and a compd. represented by formula II. In the formula I, each of R1 and R2 is H or methyl and (n) is an integer of 1-25. In the formula II, each of R3 -R5 is alkylene, etc., and each of R6 -R8 is a residue obtd. at the time when an isocyanate reacts with a compd. having active hydrogen.

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 suitable for precision metal processing such as production of a lead frame for mounting an IC chip (hereinafter referred to simply as "lead frame"), production of a metal mask, and photosensitivity using the same. About the film.

[0002]

2. Description of the Related Art There are two methods of precision metal processing of lead frames, metal masks, and the like: a stamping method of punching out using a whole die, and an etching method of forming an image by a photographic method using a photosensitive resin and then etching. It is roughly divided into two.

[0003] Under the recent trend of semiconductor devices becoming lighter, thinner and smaller, and to have a small number of products, the stamping method cannot produce narrow products due to the miniaturization, and also requires a die cost due to the small number of products. There is a problem of soaring, and a narrow product can be manufactured in order to reduce the length of a book and increase the number of products in a small number, and an etching method that does not require a mold is advantageous. The photosensitive resin used in such an etching method includes a water-soluble liquid photosensitive resin, a solvent-containing liquid photosensitive resin, and a photosensitive film.
There is one.

[0004] When a liquid photosensitive resin is used, enormous investment is required for a coating apparatus, and the coating takes a considerable amount of time. The photosensitive resin itself and the usable life after coating the photosensitive resin are long. There are common drawbacks such as shortness and low sensitivity.
Further, as an individual disadvantage, since the water-soluble liquid photosensitive resin hardens casein or PVA (polyvinyl alcohol) using a chromate, a complicated waste liquid treatment process for treating harmful heavy metal salts after use is required. . In the case of the solvent-containing liquid photosensitive resin, the organic solvent is discharged during the coating, which may adversely affect the environment.

On the other hand, in the photosensitive film method, an image is formed after the photosensitive film is heat-pressed on a base metal and used, so that the equipment investment is lower than that of the liquid photosensitive resin, the sensitivity is high, and the working life is longer. Has a feature that it is long, and is attracting attention as a method suitable for precision metal working.

Conventional photosensitive films include 42 alloy (Fe / Ni = 58/42) and S
There is a problem called etching that has poor adhesion to US and the like, and that the etching solution easily penetrates into the interface between the resist and the metal at the time of etching and the metal surface layer portion is easily attacked.

The photosensitive resin based on the component (D) used in the present invention is described in JP-A-7-278254, JP-A-3-50549, and the like. It is described as a use, and good adhesion cannot be given to 42 alloy (Fe / Ni = 58/42), SUS or the like by itself.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to use 42 alloy (Fe / Ni = 58/42) or SUS used as a base metal.
In particular, an object of the present invention is to provide a photosensitive resin composition that improves adhesion to an alloy containing iron.

Another object of the present invention is to provide a 42 alloy (Fe / Ni = 58/42) or SUS used as a base metal.
In particular, it is an object of the present invention to provide a photosensitive resin composition which improves adhesion to an alloy containing iron, and prevents the infiltration of an etching solution into an interface between a resist and a metal during etching.

Another object of the present invention is to provide a 42 alloy (Fe / Ni = 58/42) or SUS used as a base metal.
A photosensitive film suitable for metal processing such as lead frames, metal masks, etc., which improves adhesion to an alloy containing iron in particular, and prevents infiltration of an etching solution into an interface between a resist and a metal during etching. To provide.

[0011]

That is, the present invention provides:
(A) A film-forming polymer of a vinyl copolymer compound having a weight average molecular weight of 30,000 to 200,000, which is obtained by copolymerizing a vinyl monomer with (meth) acrylic acid ester and (meth) acrylic acid as copolymerization components. , (B)
A photopolymerization initiator, (C) an ethylenically unsaturated compound represented by the following general formula (I), and

[0012]

Embedded image (R ₁ and R ₂ in the formula represent a hydrogen atom or a methyl group, and n
Represents an integer of 1 to 25. (D) a compound represented by the following general formula (II)

[0013]

Embedded image (In the formula, R ₃ , R ₄ , and R ₅ are each independently any one of an alkylene group, a substituted alkylene group, an alkyleneoxy group, an aryl group, and a substituted aryl group, and R ₆ , R ₇ , and R ₈
And each independently represents a residue obtained when an isocyanate and a compound having active hydrogen are reacted. The present invention provides a photosensitive resin composition which is used for etching a metal which can be developed with a dilute alkaline aqueous solution, and a photosensitive film using the same.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The photosensitive resin composition of the present invention comprises the above components (A), (B), (C) and (D) as essential components, components (A) and (B). The component, (C) component and (D) component are mixed at a ratio of 40 to 80 parts by weight of component (A) based on 100 parts by weight of the total amount of component (A), component (C) and component (D). It is preferable that the component (B) is 0.10 to 20 parts by weight, the component (C) is 10 to 59.5 parts by weight, and the component (D) is 0.5 to 10 parts by weight.

As the polymer for imparting film properties to be used as the component (A) in the present invention, alkyl (meth) acrylate [(meth) acrylic acid means methacrylic acid and / or acrylic acid. The same applies below) and (meta)
A vinyl copolymer compound obtained by copolymerizing acrylic acid and a vinyl monomer copolymerizable therewith is exemplified. These vinyl copolymer compounds are used alone or in combination of two or more.

Examples of the alkyl (meth) acrylate include methyl (meth) acrylate,
Examples include ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Examples of the vinyl monomer copolymerizable with the alkyl (meth) acrylate and the (meth) acrylic acid include, for example, tetrahydrofurfuryl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and (meth) acrylate. Acrylic acid diethylaminoethyl ester, methacrylic acid cricidyl ester, 2,2,2-trifluoroethyl (meth)
Acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, acrylamide, diacetone acrylamide, styrene, vinyltoluene and the like can be mentioned.

If the weight-average molecular weight of the vinyl copolymer compound (measured using GPC and converted into standard polystyrene) is less than 30,000, the water resistance decreases,
If the adhesion of the resist is inferior, if it exceeds 200,000, development becomes difficult and the resolution becomes poor. The preferred weight average molecular weight is 50,000 to 150,000.

In the present invention, the compounding amount of the component (A) is 4
The amount is preferably from 0 to 80 parts by weight (so that the total amount of the components (A) and (C) and the component (D) is 100 parts by weight), and more preferably from 50 to 70 parts by weight. It is particularly preferred that the amount be 55 to 65 parts by weight. When the amount is less than 40 parts by weight, the photocured product becomes brittle, and when used as a photosensitive film, the coating properties tend to be poor. When the amount exceeds 80 parts by weight, sufficient sensitivity tends not to be obtained. .

Examples of the photopolymerization initiator used as the component (B) in the present invention include aromatic ketones (benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N, N '-Tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-ethylanthraquinone, phenanthrenequinone, etc., benzoin (benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, etc.) Benzoin ether, methylbenzoin, ethylbenzoin, etc.), benzyl derivatives (benzyldimethylketal, etc.), 2,4
5-triarylimidazole dimer (2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer 2- (o-fluorophenyl) 4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl)
-4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5
-Diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, etc., acridine derivatives (9-phenylacridine, 1,7-bis (9,9'-acridinyl)) Heptane, etc.), ethyl dimethylaminobenzoate, diethylthioxanthone and the like. These are used alone or in combination of two or more.

The compounding amount of the component (B) in the present invention is as follows:
0.10 to 20 parts by weight, preferably 0.15 to 20 parts by weight.
To 15 parts by weight, more preferably 0.20 to 1 part by weight.
It is particularly preferable to use 0 parts by weight. When the blending amount is 0.
If the amount is less than 10 parts by weight, the photocurability tends to be poor and sufficient sensitivity tends not to be obtained. If the amount exceeds 20 parts by weight, the sensitivity tends to be high and the resolution tends to be poor.

The ethylenically unsaturated compound represented by the general formula (I) used as the component (C) in the present invention includes:
For example, a compound obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol (eg, polyethylene glycol di (meth) acrylate) is exemplified. The total (n) of the number of repeating units of the ethyleneoxy group is 1 to 25, and preferably 3 to 14. If this number exceeds 25, the cured density of the resist will decrease, and etching resistance will occur due to the decrease in chemical resistance.

In the present invention, the compounding amount of the component (C) is 1
0 to 59.5 parts by weight, preferably 15 to 50 parts by weight.
The amount is more preferably set to 20 parts by weight, particularly preferably 20 to 40 parts by weight. If the compounding amount is less than 10 parts by weight, sufficient sensitivity cannot be obtained, and the cured density of the resist is low, so that etching tends to occur. 59.
If the amount exceeds 5 parts by weight, the photosensitive resin becomes soft, so that the photosensitive resin tends to protrude from the edge of the photosensitive film.

As the compound represented by the general formula (II) used as the component (D) in the present invention, for example, Sumidur BL3175 (trade name of Sumitomo Bayer Urethane Co., Ltd.) is available. Applicable.

In the compound represented by the formula (II), R ₃ , R ₄ and R ₅ are preferably an alkylene group having 1 to 15 carbon atoms, and the hydrogen atom of the alkylene group is a carbon atom such as a methyl group or an ethyl group. A substituted alkylene group, an alkyleneoxy group, and a carbon number of 8 substituted with a substituent such as an alkyl of the formulas 1 to 6,
And a substituted aryl group in which a hydrogen atom of an aromatic ring is substituted with a substituent such as a hydroxyl group, an amino group, or an alkyl group having 1 to 4 carbon atoms. Examples of the compound having an active hydrogen forming R ₆ , R ₇ and R ₈ include the above-mentioned oximes such as ketoxime, lactams such as ε-caprolactam, alkanols such as methanol, ethanol, isopropyl alcohol and ethoxyethanol, and phenol. , O-nitrophenol, halogenated phenol, o-, m-,
Examples include phenols such as p-cresol and active methylene compounds such as acetylacetone. These active compounds react with isocyanate groups bonded to R ₃ , R ₄ , and R _{5 and} are bonded to R ₆ , R ₇ , and R ₈ via an —NHCO— bond. Preferred specific examples of R ₆ , R ₇ and R ₈ include-
ON = CCH ₃ C ₂ H ₅ (residue obtained when ketoxime reacts as a compound having isocyanate and active hydrogen).

The amount of the component (D) in the present invention is as follows:
0.5 to 10.0 parts by weight, preferably 1.0 to 1.0 parts by weight.
To 7.0 parts by weight, more preferably 2.0 to 7.0 parts by weight.
Particularly preferred is 5.0 parts by weight. If the amount is less than 0.5 part by weight, etching tends to occur, and if it exceeds 10.0 parts by weight, the resolution tends to decrease, and it becomes difficult to remove the resist from the substrate after etching.

The photosensitive resin composition of the present invention may contain, if necessary, a plasticizer, a thermal polymerization inhibitor, a dye, a pigment such as leuco crystal violet, malachite green, a filler,
You may mix | blend an adhesion imparting agent, a fragrance | flavor, an imaging agent, etc.

The photosensitive resin composition of the present invention may be used on a metal surface, for example, an iron-based alloy such as copper, copper-based alloy, nickel, chromium, iron, and stainless steel, preferably a metal of copper, copper-based alloy, or iron-based alloy. On the surface, after applying and drying as a liquid resist, a protective film is coated or used, or the photosensitive resin composition layer of the present invention is formed on a support and the photosensitive film is laminated on the metal surface. It is preferably used as a photosensitive film. The thickness of the photosensitive resin composition layer,
Depends on the application, but the thickness after drying is 10-100 μm
It is preferred that it is about.

When used as a liquid resist, an inert polyolefin film such as polyethylene or polypropylene is used as a protective film. When used as a photosensitive film, a photosensitive film is prepared by applying and drying a photosensitive resin composition on a support such as polyester.

In the formation of a resist and the production of a photosensitive film, the photosensitive resin composition may be mixed with acetone, if necessary.
It may be mixed with a solvent such as methyl ethyl ketone, methylene chloride, toluene, methanol, ethanol, propanol, butanol, methyl glycol, ethyl glycol, propylene glycol, monomethyl ether of these glycols, or a mixed solvent thereof, or applied as a solution.

The photosensitive resin composition layer is irradiated with actinic rays through a negative or positive mask pattern called an artwork in a pattern, and then developed with a developing solution.
This is used as a resist pattern. As a light source of the actinic ray used at this time, for example, a carbon arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a xenon lamp or the like that effectively emits ultraviolet rays is used.

As the developing solution, one that is safe and stable and has good operability is used. For an alkali developing type photoresist, a dilute solution of sodium carbonate or the like is used. Development methods include a dip method and a spray method, and a high-pressure spray method is most suitable for improving resolution.

As processing after development, heating (80 to 250 ° C.) and exposure (0.2 to 5 mJ / cm ² ) are performed as necessary.
The resist may be further cured for use.

For the etching performed after the development,
Although a copper solution, a ferric chloride solution, an alkaline etching solution, and a hydrogen peroxide-based etching solution can be used, it is preferable to use a ferric chloride solution from the viewpoint of a good etch factor.

[0034]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Examples 1 to 3 and Comparative Examples 1 to 3 The materials shown in Table 1 were blended to obtain solutions.

[0035]

[Table 1] The components (C) and (D) shown in Table 2 were dissolved in this solution to obtain a solution of the photosensitive resin composition.

[0036]

[Table 2] * 1 Tetraethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK-4G) * 2: Compound represented by the following formula

[0037]

Embedded image * 3: Polyethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK-14G), general formula (I)
N = 14 * 4: 2,2'-bis (4-methacryloxypentaethoxyphenyl) propane (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: BPE-10) Then, a solution of this photosensitive resin composition was prepared. Apply evenly on a 20 μm thick polyethylene terephthalate film,
Drying was performed for 10 minutes with a hot air convection dryer at 100 ° C. to obtain a photosensitive film. The dried film thickness of the photosensitive resin composition layer was 15 μm.

On the other hand, a 42-alloy base material (manufactured by Yamaha Corporation) having a thickness of 0.15 mm was immersed in a 3% by weight NaOH solution at 50 ° C. for 2 minutes, and then washed and dried. Was heated and laminated at 110 ° C.

Next, at this time, in order to be able to evaluate the light sensitivity, a negative film (optical density 0.05 was set as the first step, and the optical density was set at each step so that the light transmission amount was reduced stepwise). Exposure was performed at a predetermined exposure amount using a step tablet (in increments of 0.15).

Next, the polyethylene terephthalate film was removed, and an unexposed portion was removed by spraying a 1% by weight aqueous solution of sodium carbonate at 30 ° C. for 40 seconds. The number of steps of the step tablet of the photocurable film formed on the 42 alloy substrate was measured. Therefore, the exposure amount corresponding to the seventh stage out of the 21 stages of the step tablet was evaluated. Table 3 shows the results.

Then, using a negative film for pattern formation, a 3 kW high-pressure mercury lamp (HMW, manufactured by Oak Manufacturing Co., Ltd.)
(−590), exposure was performed with an exposure amount corresponding to the seventh stage out of the 21st stage of the step tablet. Next, the polyethylene terephthalate film was removed, and a 1% by weight aqueous solution of sodium carbonate was sprayed at 30 ° C. for 40 seconds,
Unexposed portions were removed.

As a treatment after development, heating was performed at 200 ° C. for 1 minute to further cure the resist.

Next, the etching was completed by spraying with a 45 Baume ferric chloride solution (the Baume represents the specific gravity of the solution; the larger the value, the higher the specific gravity) at 50 ° C. and a pressure of 0.3 MPa for 8 minutes to complete the etching, and 3 wt. % NaOH solution (50 ° C)
The resist was peeled off, washed with water and dried to obtain an etched 42 alloy base material. Table 3 shows the time required for peeling. The line of the obtained 42 alloy base material was observed, and the etching hole was examined. Table 3 also shows the results.
Shown in

[0044]

[Table 3] As is clear from Table 3, when the photosensitive resin compositions of Examples 1 to 3 containing the compounds corresponding to the general formula (II) as the components (C) and (D) were used, each comparative example was used. It was confirmed that the etching was smaller and the sensitivity was improved, and the stripping time was shortened.

[0045]

According to the photosensitive resin composition of the present invention, a 42 alloy (Fe / Ni = 58/4) used as a base metal is used.
2) It has excellent adhesion to SUS and other alloys, especially iron-containing alloys, and when used as a photosensitive resin composition for etching, prevents the infiltration of the etching solution into the interface between the resist and the metal during etching. Is excellent.

The photosensitive film of the present invention has excellent adhesion to 42 alloy (Fe / Ni = 58/42) or SUS used as a base metal, particularly to an alloy containing iron,
It is excellent in preventing the infiltration of the etching solution into the interface between the resist and the metal at the time of etching, and is suitable for metal processing such as a lead frame and a metal mask.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03F 7/033 G03F 7/033 H01L 21/027 H05K 3/06 H H05K 3/06 J 3/12 D 3/12 3/28 D 3/28 H01L 23/50 A // H01L 23/50 21/30 502R

Claims (3)

[Claims] 1. A weight-average molecular weight of 30,000 to 2 obtained by copolymerizing a vinyl monomer with (A) a (meth) acrylic acid ester and (meth) acrylic acid as copolymerizing components.
A film-forming polymer of a vinyl copolymer compound of 000, (B) a photopolymerization initiator, (C) an ethylenically unsaturated compound represented by the following general formula (I), and (R ₁ and R ₂ in the formula each independently represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 25.) (D) Compound represented by the following general formula (II) 2] (In the formula, R ₃ , R ₄ , and R ₅ are each independently any one of an alkylene group, a substituted alkylene group, an alkyleneoxy group, an aryl group, and a substituted aryl group, and R ₆ , R ₇ , and R ₈
And each independently represents a residue obtained when an isocyanate and a compound having active hydrogen are reacted. A) a photosensitive resin composition used for etching a metal which can be developed with a dilute alkaline aqueous solution. 2. The mixing ratio of the component (A), the component (B), the component (C) and the component (D) is based on 100 parts by weight of the total amount of the components (A), (C) and (D). Component (A) is 40 to 80 parts by weight, component (B) is 0.10 to 20 parts by weight, component (C) is 10 to 59.5 parts by weight, and component (D) is 0.5 to 10 parts by weight. The photosensitive resin composition according to claim 1, which is: 3. A photosensitive film obtained by forming a photosensitive layer comprising the photosensitive resin composition according to claim 1 on a support.