JP3224211B2 - Solder resist composition and printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder resist composition and a printed wiring board, and more particularly to a solder resist composition which is easy to apply by a roll coater and has little migration of lead, and a printed wiring using the solder resist composition. Suggest board.

[0002]

2. Description of the Related Art A printed wiring board has a solder resist layer formed on the outermost layer. This solder resist layer has a function to protect the conductor circuit exposed on the surface layer, and a function as a dam to prevent the solder outflow and solder bridge of the solder body (for example, solder bump) supplied to the pad surface on which the electronic components are mounted. Have.

As a resin composition for forming such a solder resist layer, for example, an epoxy acrylate and an imidazole curing agent such as cellosolve acetate disclosed in JP-A-63-286841 (US Pat. No. 4,902,726) are used. And the viscosity thereof is adjusted to 0.1 to 0.2 Pa · s. JP-A-62-23036 discloses an alkali development type solder resist composition.

[0004]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
When the resin composition described in JP-A-63-286841 is used as a solder resist layer, lead ions diffuse from the solder body (solder bumps or the like) formed on the pads into the solder resist layer (this phenomenon is referred to as migration of lead). There is a problem in that conduction between the pads is caused to cause a short circuit. Further, when the resin composition described in JP-A-62-23036 is used as a solder resist layer, the above-mentioned phenomenon is also caused, and there is a problem that a short circuit is caused.

On the other hand, when the above resin composition is applied to a copper pattern and dried, the copper pattern under such a resin layer is oxidized, and when nickel-gold plating is performed, an oxide layer of the copper pattern is formed. Dissolves to cause discoloration called a halo phenomenon.

Further, when the above resin composition is used as a solder resist layer, there is a problem that such a solder resist layer is easily peeled off by a heat cycle.

Further, a printed wiring board is basically a double-sided wiring board, in which case the solder resist composition must be applied to both sides. Therefore, as a best mode of application, there is a method in which a wiring substrate is sandwiched between a pair of application rolls of a roll coater in a state of standing upright, and a solder resist composition is simultaneously applied to both surfaces of the substrate. However, when this method is adopted, there is a problem that the viscosity of the solder resist composition according to the prior art is too low and the composition sags.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned various problems of the prior art, and a main object of the present invention is to develop a solder resist composition which can be easily applied by a roll coater and has little lead migration. It is in. Another object of the present invention is to provide a printed wiring board in which a solder resist layer is not peeled off due to a halo phenomenon or a heat cycle.

[0009]

Means for Solving the Problems The inventors of the present invention have earnestly studied for realizing the above object, and have obtained the following knowledge. That is, the resin composition described in the above-mentioned JP-A-63-286841 has a low viscosity (0.1 to 0.2 Pa · s), a gap exists between molecular chains, and this is dried and exposed and cured. Also, the curing rate is low, and this gap remains. Therefore, it is considered that lead ions may move through this gap.

In the resin composition described in JP-A-62-23036, a carboxylic acid is introduced into an epoxy group.
In alkali development, the molecular chains are chemically cut, so that the development surface becomes rough, and it is considered that lead ions may diffuse from the rough surface.

Further, in the above resin composition containing cellosolve acetate as a solvent, since -COOR is decomposed to generate free oxygen (O), it is considered that this oxidizes the copper surface.

The present invention has been developed based on such knowledge, and the gist configuration thereof is as follows. (1) Novolak type epoxy resin acrylate, imidazole curing agent and acrylate ester polymer, the acrylate polymer has a molecular weight of 500 to 5000
Wherein acrylic acid or methacrylic acid has 1 carbon atom
(10) A solder resist composition, which is a polymer of an ester with an alcohol of (10). (2) Novolak-type epoxy resin acrylate, including imidazole curing agent and acrylate polymer, acrylate polymer has a molecular weight of 500-5000
Wherein acrylic acid or methacrylic acid has 1 carbon atom
A polymer of an ester with an alcohol having a viscosity of 0.5 to 10 at 25 ° C. using a glycol ether solvent.
It is a solder resist composition adjusted to Pa · s.

Further, the solder resist composition described in the above (1) and (2) contains a compound having a structure of the following chemical formula 5 as an initiator, and a compound of the following chemical formula 6 as a photosensitizer.
It is preferable to include a compound having the structure:

Embedded image

Embedded image Further, in the solder resist composition according to the above (1) and (2), the imidazole curing agent is preferably liquid at 25 ° C.

(4) In a printed wiring board having a solder resist layer on the surface of a wiring board on which a conductor circuit is formed,
The solder resist layer is composed of a novolak epoxy resin acrylate, an imidazole curing agent, and a molecular weight of 500.
~ 5000, containing a polymer of an ester of acrylic acid or methacrylic acid and an alcohol having 1 to 10 carbon atoms, and using a glycol ether solvent, the viscosity is 25 ° C
A printed wiring board characterized by being formed by curing a solder resist composition adjusted to 0.5 to 10 Pa · s. (5) For the wiring board on which the conductor circuit is formed, a solder resist layer is provided on the surface thereof, and a part of the conductor circuit exposed from the opening provided in the solder resist layer is formed as a pad, and the pad is formed on the pad. In a printed wiring board that supplies and holds a solder body, the solder resist layer includes an acrylate of a novolak type epoxy resin,
A printed wiring board comprising, as main components, an imidazole curing agent and a polymer of an ester of acrylic acid or methacrylic acid and an alcohol having 1 to 10 carbon atoms having a molecular weight of 500 to 5,000.

In the printed wiring board according to the above (4) or (5), the solder resist layer comprises an initiator having a structure represented by the following chemical formula 7 and a photosensitizer having a structure represented by the following chemical formula 8: It is preferred to include.

Embedded image

Embedded image Further, in the printed wiring board according to the above (4) or (5), it is preferable that a roughened layer is formed on a surface of the conductor circuit, and the roughened layer is made of copper-nickel-phosphorus. It is desirable that the alloy layer be made of

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One feature of the solder resist composition of the present invention is that it is a resin composition containing acrylate of novolak type epoxy resin and imidazole curing agent as main components. Therefore, the solder resist layer obtained by curing this resin composition has excellent heat resistance and alkali resistance, does not deteriorate even at the temperature at which the solder melts (around 200 ° C), and is decomposed with a plating solution such as nickel plating or gold plating. Nothing to do. Further, since the solder resist composition can be developed with a solvent, the developed surface is not roughened unlike the case of alkali development.

The solder resist composition of the present invention uses a glycol ether-based solvent as a solvent and has a viscosity of 25.
Another characteristic is that the temperature is 0.5 to 10 Pa · s, more preferably 2 to 3 Pa · s at ° C. According to the solder resist composition adjusted to have a viscosity of 0.5 Pa · s or more at 25 ° C.,
In the obtained solder resist layer, the gap between the resin molecular chains is small, and the diffusion of Pb (migration of lead) moving in the gap is reduced, so that the short circuit failure of the printed wiring board is reduced. Also, if the viscosity of the solder resist composition is 0.5 Pa · s or more at 25 ° C., the composition does not sag even when applied simultaneously on both sides while the substrate is set upright, and good application is possible. Becomes However,
If the viscosity of the solder resist composition exceeds 10 Pa · s at 25 ° C., application by a roll coater cannot be performed, so the upper limit was set to 10 Pa · s.

Here, as the acrylate of the novolak type epoxy resin, an epoxy resin obtained by reacting glycidyl ether of phenol novolak or cresol novolak with acrylic acid, methacrylic acid or the like can be used.

Various imidazole curing agents can be used, but are desirably liquid at 25 ° C. This is because uniform kneading is difficult with powder, and liquid can be kneaded more uniformly. As such a liquid imidazole curing agent, 1-benzyl-2-methylimidazole (product name: 1B2MZ
), 1-cyanoethyl-2-ethyl-4-methylimidazole (product name: 2E4MZ-CN), and 4-methyl-2-ethylimidazole (product name: 2E4MZ). The addition amount of the imidazole curing agent is desirably 1 to 10% by weight based on the total solid content of the solder resist composition. The reason for this is that if the added amount is within this range, uniform mixing is easy.

Since the above solder resist composition uses a glycol ether-based solvent as a solvent, the solder resist layer using such a composition does not generate free oxygen and does not oxidize the surface of the copper pad. It is also less harmful to the human body. As such a glycol ether-based solvent, one having the following structural formula, particularly preferably diethylene glycol dimethyl ether (DMD
G) and at least one selected from triethylene glycol dimethyl ether (DMTG). This is because these solvents can completely dissolve benzophenone and Michler's ketone as reaction initiators by heating at about 30 to 50 ° C. CH ₃ O— (CH ₂ CH ₂ O) _n —CH ₃ (n = 1 to 5) The glycol ether solvent is preferably 10 to 40% by weight based on the total weight of the solder resist composition.

In addition to the solder resist composition described above, various defoaming agents and leveling agents, thermosetting resins for improving heat resistance and base resistance and imparting flexibility,
A photosensitive monomer or the like can be added to improve the resolution. Further, a dye or a pigment may be added to the solder resist composition. This is because the wiring pattern can be hidden. It is desirable to use phthalocyanine green as this dye.

In particular, in the present invention, it is desirable to add an acrylate polymer having a molecular weight of about 500 to 5,000 to the solder resist composition. This polymer is 25 ° C
Because it is liquid and easily compatible with cresol novolak epoxy resin acrylate, and has a leveling action and a defoaming action. For this reason, the formed solder resist layer has excellent surface smoothness, and has no repelling or unevenness due to bubbles. In addition, this polymer has compatibility with the photosensitive resin component, and does not disperse in the resin component to lower the light transmittance, so that development residue hardly occurs.

The acrylate polymer used in the present invention is desirably an ester polymer of alcohol having 1 to 10 carbon atoms and acrylic acid, methacrylic acid or a derivative thereof. The alcohol having 1 to 10, preferably 3 to 8 carbon atoms used in the present invention includes propyl alcohol, isopropyl alcohol, n
Monohydric alcohols such as -butyl alcohol, tert-butyl alcohol, isobutyl alcohol, pentyl alcohol, hexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, amyl alcohol, and polyhydric alcohols such as 1,2-ethanediol.

The polymer of the acrylic ester has excellent compatibility with cresol novolak epoxy resin acrylate, and particularly, 2-ethylhexyl acrylate (2EHA), butyl acrylate (BA), ethyl acrylate (EA) and hydroxyethyl A polymer of at least one acrylate ester selected from acrylates (HEA) is desirable. Since 2-ethylhexyl acrylate is branched, it can impart a surface active effect, and prevents the plating resist from being repelled by dust or the like. Also, butyl acrylate plays a leveling and defoaming action, and ethyl acrylate and hydroxyethyl acrylate are thought to improve compatibility. The four types of acrylates may be used alone or in combination of two or more types, or may be used alone or in combination of two or more types of acrylates selected from the four types of acrylates. You may use it.

For example, when all of the four acrylates are used, the weight composition ratio of 2-ethylhexyl acrylate / butyl acrylate is preferably 40/60 to 60/40, and a mixture of 2-ethylhexyl acrylate and butyl acrylate is preferred. / Ethyl acrylate is 90/10 ~ 97 /
3, mixture of 2-ethylhexyl acrylate and butyl acrylate / hydroxyethyl acrylate is 95/5
99/1 is desirable.

The molecular weight of such an acrylic acid ester polymer is preferably about 500 to 5,000. In this range, 25
It is liquid at ℃ and easily mixes with the photosensitive resin when preparing the solder resist. When the molecular weight exceeds 5,000, the viscosity increases, and the leveling action and the defoaming action decrease. Conversely, when the molecular weight is less than 500, no leveling action or defoaming action is observed. Furthermore, the particularly desirable molecular weight of the acrylate polymer is from 2,000 to 3,000. In this range, the viscosity becomes 250 to 550 cp (at 25 ° C.), and it becomes easier to prepare a solder resist.

The amount of the acrylate polymer added is
It is desirable to use 0.1 to 5 parts by weight, preferably 0.2 to 1.0 part by weight, per 100 parts by weight of the photosensitive resin component. 0.1
If the amount is less than 5 parts by weight, the leveling action and the defoaming action are reduced, and Pb migration and cracks due to bubbles are easily generated. Conversely, if the amount is more than 5 parts by weight, the glass transition point is reduced and the heat resistance is reduced. Because.

In the present invention, a compound having a structure represented by the following chemical formula 9 is added to the solder resist composition as an initiator:
It is desirable to add a compound having the structure of the following chemical formula 10 as a photosensitizer. This is because these compounds are easily available and have high safety for the human body.

Embedded image

[Formula 10]

As the thermosetting resin mentioned as an additional component, a bisphenol type epoxy resin can be used. The bisphenol type epoxy resin includes a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, and when the basic resistance is important, the former is required when a low viscosity is required (when the application property is important). ) Is better for the latter.

Further, as the photosensitive monomer mentioned as an additional component, a polyvalent acrylic monomer can be used. This is because the polyvalent acrylic monomer can improve the resolution. For example, a polyacrylic monomer having a structure represented by the following chemical formulas 11 and 12 is desirable. Here, chemical formula 11 is DPE manufactured by Nippon Kayaku.
-6A, and the chemical formula 12 is R-604 manufactured by Kyoeisha Chemical.

[0031]

[Formula 11]

Embedded image

Further, benzophenone (BP) or Michler's ketone (MK) may be added to the solder resist composition. This is because these act as an initiator and a reaction accelerator. It is desirable that BP and MK are simultaneously dissolved in a glycol ether-based solvent heated to 30 to 70 ° C., uniformly mixed, and mixed with other components. This is because there is no dissolution residue and it can be completely dissolved.

The printed wiring board of the present invention is a printed wiring board having a solder resist layer on the surface of a wiring board on which a conductive circuit is formed, wherein the solder resist layer is cured by the above-described solder resist composition of the present invention. It is characterized by comprising. That is, the solder resist layer is a cured product of a resin composition mainly containing acrylate of novolak type epoxy resin and imidazole curing agent.

In the printed wiring board of the present invention, the wiring board is not particularly limited, but a plating resist is formed on a resin insulating material whose surface is roughened, and a pad is formed in a portion where the plating resist is not formed. It is desirable to use a so-called additive printed wiring board or a build-up multilayer printed wiring board on which a conductive circuit is formed. When applying a solder resist composition to such a wiring board,
The opening diameter of the solder resist layer can be larger than the conductor pad diameter. As a result, the plating resist, which is a resin, repels the solder without repelling the solder, so that it acts as a dam for the solder. Conversely, make the opening diameter of the solder resist layer smaller than the pad diameter,
It is also possible to cover a part of the pad with a solder resist layer. In this case, the roughened layer of the pad bites into the solder resist, and the solder resist layer and the pad are in close contact with each other, so that peeling of the pad can be suppressed.

In the printed wiring board of the present invention, the thickness of the solder resist layer is preferably 5 to 30 μm. If it is too thin, the effect of the solder body as a dam decreases,
This is because if it is too thick, development processing is difficult.

Further, as a more preferable configuration as the printed wiring board of the present invention, as shown in FIG. 3 and FIG. 24, a solder resist layer is provided on the surface of In a printed wiring board formed by forming a part of the conductor circuit exposed from an opening provided in a layer as a pad and supplying and holding a solder body on the pad, the solder resist layer according to the present invention is used as a solder resist composition. The conductor circuit is constituted by a cured product, and a roughened layer is formed on the surface of the conductor circuit. In a printed wiring board having such a structure, the roughened layer formed on the surface of the conductive circuit including the pads (portions on which the IC chip and electronic components are mounted) acts as an anchor, so that the conductive circuit and the solder resist layer are firmly connected. Closely adhered. Further, the adhesiveness of the solder body supplied and held on the pad surface is also improved. In particular, acrylates of novolak-type epoxy resins have a rigid skeleton and thus are excellent in heat resistance and base resistance, but lack flexibility and are liable to peel off under high-temperature and high-humidity conditions. In this regard, according to the above configuration in which the roughened layer is formed on the surface of the conductor circuit, such peeling can be prevented.

Here, the roughened layer is desirably formed by any one of a polishing process, an etching process, an oxidation-reduction process, and a plating process. Of these processes,
The oxidation-reduction treatment was performed using NaOH (10 g / l), NaClO ₂ (40 g /
l), Na ₃ PO ₄ (6 g / l) was converted into an oxidation bath (black bath), NaOH
(10 g / l), NaBH ₄ (5 g / l) as a reducing bath, and the plating treatment was copper sulfate 8 g / l, nickel sulfate 0.6
g / l, citric acid 15g / l, sodium hypophosphite 29g
/ L, boric acid 31 g / l and surfactant 0.1 g / l, it is preferable to use an electroless plating bath for copper-nickel-phosphorus plating at pH = 9. In particular, copper-nickel-
This is because the roughened layer of the alloy layer formed by the phosphor plating has a needle-like structure and is hardly embedded in the solder resist layer, so that the anchor effect contributes to improving the adhesion to the solder resist layer. Also, since this roughened layer is electrically conductive,
Even if a solder body is formed on the pad surface, there is no need to remove it.

The composition of the alloy layer constituting the roughened layer is as follows:
90 to 96 wt%, 1 for copper, nickel and phosphorus
It is desirable that the content be 5 to 5% by weight and 0.5 to 2% by weight. This is because these compositions have a needle-like structure at these composition ratios.
Further, the thickness of the roughened layer is desirably 0.5 to 7 μm. This is because if the thickness is too large or too small, the adhesion to the solder resist layer or the solder body is reduced.

When a solder body is supplied and held on a pad, the surface of the pad is preferably plated with nickel-gold. The nickel layer improves the adhesion with copper,
In addition, the adhesiveness to gold is excellent, and the gold layer is well compatible with the solder body. The solder body may be layered,
It may be a ball-shaped so-called “solder bump”.

Next, one method of manufacturing a printed wiring board according to the present invention will be described. (1) First, a wiring board having an inner copper pattern formed on the surface of a core board is manufactured. The copper pattern is formed on the core substrate by etching the copper clad laminate, or
An adhesive layer for electroless plating is formed on a substrate such as a glass epoxy substrate, a polyimide substrate, a ceramic substrate, or a metal substrate, and the surface of the adhesive layer is roughened to a roughened surface, which is then subjected to electroless plating. There is a way. Further, if necessary, an adhesive layer for electroless plating is formed on the wiring substrate, an opening for a via hole is formed in this layer, the surface of the layer is roughened, and electroless plating is performed thereon to form a copper pattern and a via. By repeating the step of forming holes, a multilayer wiring board can be obtained. Note that a through hole is formed in the core substrate, and the wiring layer on the front surface and the back surface can be electrically connected through the through hole.

(2) Next, an interlayer resin insulating material layer is formed on the wiring board prepared in the above (1). In particular, in the present invention,
It is desirable to use the above-mentioned adhesive for electroless plating as an interlayer resin insulating material. This adhesive for electroless plating
It is most preferable that heat-resistant resin particles soluble in an acid or an oxidizing agent subjected to curing treatment are dispersed in an uncured heat-resistant resin hardly soluble in an acid or an oxidizing agent. In the adhesive for electroless plating, in particular, the cured heat-resistant resin particles include a heat-resistant resin powder having an average particle size of 10 μm or less, and a heat-resistant resin powder having an average particle size of 2 μm or less. Particles, a mixture of a heat-resistant powder resin powder having an average particle diameter of 10 μm or less and a heat-resistant resin powder having an average particle diameter of 2 μm or less, and an average particle diameter of 2 μm on the surface of the heat-resistant resin powder having an average particle diameter of 2 to 10 μm Pseudo particles obtained by adhering at least one of the following heat-resistant resin powders or inorganic powders, heat-resistant resin particles having an average particle diameter of 0.1 to 0.8 μm and heat resistance having an average particle diameter of more than 0.8 μm and less than 2 μm It is desirable to use at least one selected from a mixture with a conductive resin particle. This is because they can form more complex anchors.

(3) After the adhesive layer for electroless plating formed in (2) is dried, openings for forming via holes are provided as necessary. In the case of a photosensitive resin, it is exposed and developed and then thermally cured. In the case of a thermosetting resin, it is thermally cured and then subjected to laser processing, so that an opening for forming a via hole is formed in the adhesive layer. Section is provided.

(4) Next, the epoxy resin particles present on the surface of the cured adhesive layer are dissolved and removed with an acid or an oxidizing agent, and the surface of the adhesive layer is roughened. Here, examples of the acid include phosphoric acid, hydrochloric acid, sulfuric acid, and organic acids such as formic acid and acetic acid, and it is particularly preferable to use an organic acid. This is because when the roughening treatment is performed, the metal conductor layer exposed from the via hole is hardly corroded. On the other hand, it is desirable to use chromic acid and permanganate (such as potassium permanganate) as the oxidizing agent.

(5) Next, a catalyst nucleus is applied to the wiring board whose surface of the adhesive layer is roughened. It is desirable to use a noble metal ion or a noble metal colloid for providing the catalyst nucleus, and generally, palladium chloride or a palladium colloid is used. Note that it is desirable to perform a heat treatment to fix the catalyst core. Palladium is preferred as such a catalyst core.

(6) Next, a plating resist is formed on the wiring substrate to which the catalyst nucleus has been applied. As the plating resist composition, it is particularly desirable to use a composition comprising an acrylate of a cresol novolak or a phenol novolak type epoxy resin and an imidazole curing agent, but other commercially available products can also be used.

(7) Next, electroless plating is applied to the portion where the plating resist is not formed to form a conductor circuit including a pad and a via hole to manufacture a printed wiring board. Here, it is desirable to use copper plating as the electroless plating.

(8) If necessary, a roughened layer is formed on the surface of the conductor circuit. Here, when forming a roughened layer by a copper-nickel-phosphorus alloy layer, this alloy layer is deposited by electroless plating. As electroless plating of this alloy, copper sulfate 1-40 g / l, nickel sulfate 0.1-6.0 g
/ L, citric acid 10-20 g / l, hypophosphite 10-100 g
/ L, boric acid 10-40 g / l, surfactant 0.01-10 g / l
It is desirable to use a plating bath having a solution composition of

(9) Next, the solder resist composition according to the present invention is applied to both surfaces of the printed wiring board after the treatment of the above (8). In particular, in the present invention, as shown in FIG.
When applying a solder resist layer to both sides of the printed wiring board, the printed wiring board is sandwiched between a pair of application rolls of a roll coater in a state where the printed wiring board is vertically erected, and is conveyed from the lower side to the upper side and the substrate is It is desirable to apply the solder resist composition on both sides simultaneously. The reason is that the current basic specifications of printed wiring boards are on both sides, and the curtain coating method (a method of flowing resin from top to bottom like a waterfall and applying it by passing a substrate through this "curtain" of resin) This is because only one side can be applied. The above-described solder resist composition of the present invention can be advantageously used for the above-described method of simultaneously applying both surfaces. That is, since the viscosity of the solder resist composition of the present invention is 1 to 10 Pa · s at 25 ° C., the composition does not flow even when the substrate is applied vertically and the transfer is good.

(10) Next, the coating film of the solder resist composition is dried at 60 to 80 ° C. for 5 to 60 minutes, and a photomask film having an opening is placed on the coating film to expose and develop. The processing forms an opening exposing the pad portion of the conductor circuit. The coating film in which the openings are formed in this manner is further cured by a heat treatment at 80 ° C. to 150 ° C. for 1 to 10 hours. Thereby, the solder resist layer having the opening is in close contact with the roughened layer provided on the surface of the conductor circuit. Here, the opening diameter of the opening may be larger than the diameter of the pad, and may be such that the pad is completely exposed. In this case, even if the photomask is displaced, the pad is not covered with the solder resist, and the solder resist does not contact the solder body and the solder body does not become constricted, so that the solder body is less likely to crack. Become. Conversely, it is also possible to make the opening diameter of the solder resist layer smaller than the diameter of the pad and cover a part of the pad with the solder resist layer. In this case, the roughened layer of the pad bites into the solder resist, and the solder resist layer and the pad are in close contact with each other, so that peeling of the pad can be suppressed.

(11) Next, nickel plating and gold plating are applied to the pad portion exposed from the opening. Specific plating solution compositions of nickel plating and gold plating are known, and are described in detail, for example, in Maki Shoten, Tokuzo Kobe, "NP Series Electroless Plating" (published on September 30, 1990). .

(12) Next, a solder body is supplied onto the pad portion exposed from the opening. As a method of supplying the solder body, a solder transfer method or a printing method can be used.
Here, in the solder transfer method, a solder foil is bonded to a prepreg, and the solder foil is etched leaving only a portion corresponding to an opening portion to form a solder pattern to form a solder carrier film. Is applied to a solder resist opening portion of a substrate, and then laminated such that a solder pattern is in contact with a pad, which is heated and transferred. on the other hand,
The printing method is a method in which a metal mask having a through-hole provided at a position corresponding to a pad is placed on a substrate, and a solder paste is printed and heated.

The above-described method is a method for manufacturing a printed wiring board called a so-called full additive method. In addition to this method, a method called a semi-additive method can be adopted. For example, a printed wiring board can be manufactured by the following method. (1) An electroless plating film is formed on the entire surface of the substrate after the step (5) in the method described above. This electroless plating film is preferably an electroless copper plating film, and its thickness is 1 to
5 μm is preferred. The reason for this is that the electroless copper plating film functions as a plating lead and is easily removed by etching. (2) A photosensitive dry film is thermocompression-bonded on the electroless plating film, then a photomask film is brought into close contact with the substrate, exposed, developed with an alkali or a solvent, and provided with a plating resist. (3) Electroplating is performed using the electroless plating film as a plating lead, and an electrolytic plating film is formed on a portion where no resist is formed.
The thickness of this electrolytic plating film is preferably 5 to 20 μm. (4) After stripping the plating resist with an alkali or a solvent, electroless plating under the plating resist with an aqueous solution of sulfuric acid-hydrogen peroxide or an aqueous solution of persulfate, ferric chloride, cupric chloride, etc. The film is dissolved and removed to form conductive circuits including pads and via holes. (5) Hereinafter, through steps (8) to (12) in the above-described method, a solder resist layer and a solder bump are formed.

[0053]

【Example】

Example 1 (1) 18 μm on both sides of a substrate 1 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 1 mm.
A copper-clad laminate obtained by laminating m copper foils 8 was used as a starting material (see FIG. 1A). The copper foil 8 of the copper-clad laminate was etched in a pattern according to a conventional method to form an inner copper pattern 4 on both surfaces of the substrate 1 (see FIG. 1B).

(2) The substrate on which the inner layer copper pattern 4 was formed in the above (1) was washed with water and dried, and then the substrate was acid-degreased and soft-etched. Then, a catalyst solution comprising palladium chloride and an organic acid was used. After treatment to give a Pd catalyst and to activate this catalyst, copper sulfate 8 g / l, nickel sulfate
0.6 g / l, citric acid 15 g / l, sodium hypophosphite
29 g / l, boric acid 31 g / l, surfactant 0.1 g / l, p
Plating was performed in an electroless plating bath consisting of H = 9, and a roughened layer (uneven layer) of Cu-Ni-P alloy having a thickness of 2.5 μm was formed on the entire surface of the copper conductor circuit 3 (however, this roughened layer was formed). Layer is not shown). Then, further, the substrate is washed with water, and 0.1 mol /
immersed in an electroless tin displacement plating bath composed of l-boron fluoride-1.0 mol / l thiourea solution at 50 ° C for 1 hour,
A tin-substituted plating layer having a thickness of 0.3 μm was formed on the surface of the -P alloy roughened layer (this tin-substituted plating layer is not shown).

(3) 70 parts by weight of a 25% acrylate of cresol novolac type epoxy resin (manufactured by Nippon Kayaku, molecular weight 2500) dissolved in DMDG (diethylene glycol dimethyl ether), 30 parts by weight of polyether sulfone (PES), and imidazole curing (Shikoku Chemicals, trade name: 2E4M
4 parts by weight of Z-CN), 10 parts by weight of caprolactone-modified tris (acroxyethyl) isocyanurate (trade name: Alonix M325, manufactured by Toagosei Co., Ltd.) as a photosensitive monomer, and benzophenone (manufactured by Kanto Chemical) 5 as a photoinitiator Parts by weight, Michler's ketone as a photosensitizer (Kanto Chemical)
5 parts by weight, 35 parts by weight of an epoxy resin particle having an average particle size of 5.5 μm with respect to this mixture, and an average particle size of 0.5 μm
m, 5 parts by weight, and then mixing while adding NMP (normal methylpyrrolidone), adjusting the viscosity to 12 Pa · s with a homodisper stirrer, and kneading with a three-roll mill. A solution (interlayer resin insulating material) was obtained.

(4) The photosensitive adhesive solution obtained in the above (3) is
On both sides of the substrate after the treatment of the above (2), apply using a roll coater, leave it in a horizontal state for 20 minutes, and then
Drying was performed for 30 minutes to form an adhesive layer 2 having a thickness of 60 μm.

(5) A photomask film having via holes drawn thereon was placed on both sides of the substrate on which the adhesive layer 2 was formed in the above (4), and was exposed to ultraviolet rays. (6) The exposed substrate was spray-developed with a DMTG (triethylene glycol dimethyl ether) solution to form an opening serving as a 100 μmφ via hole in the adhesive layer 2. Further, the substrate is 3,000
Exposure at mJ / cm ² for 1 hour at 100 ° C, then 5 ° C at 150 ° C
By performing heat treatment over time, an adhesive layer 2 having a thickness of 50 μm and having an opening (opening 6 for forming a via hole) having excellent dimensional accuracy corresponding to a photomask film was formed. Note that the tin plating layer is partially exposed in the opening 6 serving as a via hole.

(7) The substrate having the via hole forming openings 6 formed in the above (5) and (6) is immersed in chromic acid for 2 minutes to dissolve and remove the epoxy resin particles present on the surface of the adhesive layer 2. Then, the surface of the adhesive layer was roughened, and then immersed in a neutralizing solution (manufactured by Shipley) and washed with water (FIG. 1 (c)).
reference).

(8) Roughening treatment (roughening depth 20 μm)
By applying a palladium catalyst (manufactured by Atotech) to the substrate subjected to m), catalyst nuclei were provided on the surfaces of the adhesive layer 2 and the via hole openings 6.

(9) 46.67 g of a photosensitizing oligomer (molecular weight: 4000) obtained by acrylated 50% of an epoxy group of a cresol novolak type epoxy resin (manufactured by Nippon Kayaku) of 60% by weight dissolved in DMDG was added to methyl ethyl ketone. 15.0 g of dissolved 80% by weight bisphenol A type epoxy resin (manufactured by Yuka Shell, Epicoat 1001), 1.6 g of imidazole hardener (manufactured by Shikoku Chemicals, trade name: 2E4MZ-CN), polyvalent acrylic as a photosensitive monomer A mixed solution A was prepared by mixing 3 g of a monomer (manufactured by Nippon Kayaku, trade name: R604) and 1.5 g of a polyvalent acrylic monomer (manufactured by Kyoeisha Chemical, trade name: DPE6A). On the other hand, 3 g of DMD prepared by heating 2 g of benzophenone as a photoinitiator (manufactured by Kanto Kagaku) and 0.2 g of Michler's ketone as a photosensitizer (manufactured by Kanto Kagaku) at 40 ° C.
G to prepare a mixed solution B. The liquid mixture A and the liquid mixture B were mixed and stirred to obtain a liquid resist composition.

(10) The liquid resist composition is applied to both surfaces of the substrate, which has been subjected to the treatment for providing catalyst nuclei in the above (8), using a roll coater, and dried at 60 ° C. for 30 minutes. 30 μm
Was formed.

(11) A mask having a pattern drawn thereon was laminated on the resist layer, and the resist layer was exposed to ultraviolet rays. (12) After exposure in the above (11), the resist layer is dissolved and developed with DMTG to form a plating resist 3 from which the conductor circuit pattern portion has been removed on the substrate, and this is further subjected to an ultra-high pressure mercury lamp.
Exposure was performed at 6000 mJ / cm ² . Further, the plating resist 3 is subjected to a heat treatment at 100 ° C. for 1 hour and then at 150 ° C. for 3 hours to obtain a permanent resist 3 formed on the adhesive layer 2.

(13) The substrate on which the permanent resist 3 has been formed is preliminarily subjected to a plating pretreatment (specifically, a sulfuric acid treatment or the like and activation of catalyst nuclei), and thereafter, is subjected to copper plating in an electroless copper plating bath. A conductor layer was formed by an additive method by depositing an electroless copper plating having a thickness of about 15 μm on the non-resist forming portion to form an outer copper pattern 5 and a via hole 7 (see FIG. 1D). . (14) Then, the substrate on which the conductor layer was formed was coated with copper sulfate 8 g /
1, nickel sulfate 0.6 g / l, citric acid 15 g / l, sodium hypophosphite 29 g / l, boric acid 31 g / l, surfactant 0.1 g / l, immersed in an electroless plating solution having a pH of 9 Then, a roughened layer 11 made of copper-nickel-phosphorus was formed on the surface of the conductor layer (see FIG. 1 (e)).

(15) On the other hand, 60% by weight dissolved in DMDG
Cresol novolak epoxy resin (Nippon Kayaku)
46.67 g of a photosensitizing oligomer (molecular weight 4000) obtained by acrylizing 50% of the epoxy groups of epoxy resin, 15.0 g of an 80 wt% bisphenol A type epoxy resin (made by Yuka Shell, Epicoat 1001) dissolved in methyl ethyl ketone, imidazole curing 1.6 g of an agent (manufactured by Shikoku Chemicals, trade name: 2E4MZ-CN), 3 g of a polyacrylic monomer which is a photosensitive monomer (trade name: R604, manufactured by Nippon Kayaku), and a polyacrylic monomer (manufactured by Kyoeisha Chemical, trade name) : DPE6A) 1.5 g and a dispersion antifoaming agent (manufactured by San Nopco, trade name: S-65) 0.71 g were mixed, and 2 g of benzophenone (Kanto Chemical) as a photoinitiator was added to this mixture. Add 0.2 g of Michler's ketone (manufactured by Kanto Chemical Co.) as a sensitizer and adjust the viscosity to 25 ° C.
Thus, a solder resist composition adjusted to 2.0 Pa · s was obtained. The viscosity was measured using a B-type viscometer (Tokyo Keiki, DVL-B
The rotor was No. 4 at 60 rpm and the rotor No. 3 at 6 rpm.

(16) The substrate obtained in the steps up to (14) is sandwiched between a pair of coating rolls 19 of a roll coater 18 shown in FIG. 2) was applied twice to form a resin layer having a thickness of 20 μm. Here, in the first coating, drying was performed at 75 ° C. for 20 minutes, and in the second coating, drying was performed at 75 ° C. for 30 minutes. (17) Next, after forming a resin layer on the surface of the substrate, the resin layer was exposed to ultraviolet rays of 1000 mJ / cm ² and subjected to DMTG development treatment. 1 hour at 80 ° C, 1 hour at 100 ° C, 120 ° C
1 hour and heat treatment at 150 ° C. for 3 hours to form a solder resist layer (thickness: 20 μm) 14 with an opening in the pad portion (opening diameter: 200 μm) (see FIG. 1 (f)).

(18) Next, the substrate on which the solder resist layer 14 was formed was coated with nickel chloride 30 g / l, sodium hypophosphite 10 g / l, sodium citrate 10 g / l, glycine 20
g / l, 2 mg / l of lead nitrate, immersed in an electroless nickel plating solution having a pH of 5.5 for 30 minutes, and a thickness of 4 μm
m of the nickel plating layer 15 was formed. Further, the substrate was washed with 2 g / l of potassium gold cyanide and 75 g of ammonium chloride.
g / l, sodium citrate 50 g / l, sodium hypophosphite 10 g / l, pH = 5 electroless gold plating solution
The gold plating layer 16 having a thickness of 0.05 μm was formed on the nickel plating layer 15 by immersion at 90 ° C. for 30 minutes (see FIG. 1 (g)). (19) Then, a solder paste is printed on the opening of the solder resist layer 14 (a solder transfer method may be used) and reflowed at 200 ° C. to form a solder bump 17, and a printed wiring board having the solder bump 17 is formed. Manufactured (Fig. 1 (h)
reference).

Comparative Example 1 Example 1 was repeated except that 14 g of DMDG was added to the composition of Example 1 (15) to adjust the viscosity to 0.2 Pa · s as the solder resist composition. The processing up to (16) was performed in the same manner as described above. However, the above-mentioned solder resist composition has a viscosity that is too low and tends to hang down, and it has not been possible to simultaneously apply both surfaces of the solder resist composition in a state where the wiring substrate is set upright. Therefore, the above-mentioned solder resist composition was applied by a curtain coating method with the wiring substrate horizontal, and a printed wiring board having solder bumps was manufactured in the same manner as in Example 1.

(Comparative Example 2) In Example 1 (15), 70%
A printed wiring board having solder bumps was manufactured in the same manner as in Example 1 except that a solder resist composition having a viscosity adjusted to 15 Pa · s was obtained using a solid cresol novolak type epoxy acrylate. In Comparative Example 2, unevenness was generated on the surface of the solder resist layer because the viscosity of the solder resist composition was too high.

(Comparative Example 3) As a solder resist composition, a composition of Experiment No. 1-1 (orthocresol novolak type epoxy resin, described in JP-A-63-286841)
The process up to (16) was carried out in the same manner as in Example 1 except that a solder resist composition containing cellosolve acetate, benzophenone and Michler's ketone and having a viscosity of 0.2 Pa · s) was used. However, the above-mentioned solder resist composition has a viscosity that is too low and tends to hang down, and it has not been possible to simultaneously apply both surfaces of the solder resist composition in a state where the wiring substrate is set upright. Therefore, the above-mentioned solder resist was applied to the surface of the wiring board by a curtain coating method according to JP-A-63-286841, and thereafter, a printed wiring board having solder bumps was manufactured in the same manner as in Example 1 above. .

(Comparative Example 4) A composition described in JP-A-62-23036 was used as a solder resist composition.
A printed wiring board having solder bumps was manufactured in the same manner as in Example 1 except that the development of the solder resist layer was performed by alkali development.

For the printed wiring board thus manufactured, the applicability of the solder resist composition was confirmed, and a HAST test (High Acceleration Stress Test) was performed. Was measured with a checker. Note that the HAST test condition is humidity
85%, temperature 135 ° C, applied voltage 3.3V, 48 hours. In addition, the presence or absence of a halo phenomenon was visually confirmed, and
A heat cycle test was performed 1000 times at 55 to 125 ° C., and the presence or absence of peeling of the solder resist layer was confirmed by an optical microscope. Table 1 shows the results.

In Example 1, which is an example of the present invention, when the solder resist composition was applied by a roll coater with the wiring board upright, the applicability was good. On the other hand, in Comparative Example 1 where the viscosity of the solder resist composition was too low and Comparative Example 2 where the viscosity was too high, the coatability of the solder resist composition was poor. In Example 1, no migration of lead was confirmed, and no short-circuit failure occurred after the HAST test due to the presence or absence of this migration. In contrast, in Comparative Examples 2 and 4,
Even when a solder resist composition having the same composition as in Example 1 was used, its migration was low because of its low viscosity, and short-circuit failure occurred after the HAST test.
Further, in Example 1, since the glycol ether-based solvent was used, the conductor circuit was not oxidized, and no halo phenomenon or peeling of the solder resist layer due to a heat cycle was observed. In contrast, in Comparative Example 3 using cellosolve acetate, a halo phenomenon and peeling due to a heat cycle were observed.

[0073]

[Table 1]

Example 2 A. Preparation of adhesive composition for electroless plating. 35 parts by weight of a resin solution prepared by dissolving a 25% acrylated cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight 2500) in DMDG at a concentration of 80 wt%, 35 parts by weight, and 3.15 parts by weight of a photosensitive monomer (Alonix M315 manufactured by Toa Gosei) Parts, 0.5 parts by weight of antifoaming agent (manufactured by San Nopco, S-65), and 3.
6 parts by weight were mixed with stirring. . After mixing 12 parts by weight of polyethersulfone (PES), 7.2 parts by weight of an epoxy resin particle (manufactured by Sanyo Chemical Industries, polymer pole) having an average particle diameter of 1.0 μm, and 3.09 parts by weight of an epoxy resin particle having an average particle diameter of 0.5 μm, Further, 30 parts by weight of NMP was added and mixed by stirring with a bead mill. . 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), a photoinitiator (Irgacure I-, manufactured by Ciba-Geigy)
907) 2 parts by weight, photosensitizer (DETX-S, manufactured by Nippon Kayaku) 0.2
Parts by weight and 1.5 parts by weight of NMP were mixed with stirring. These were mixed to prepare an adhesive composition for electroless plating.

B. Preparation of lower interlayer resin insulation agent 35 parts by weight of a resin solution prepared by dissolving a 25% acrylate of cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) at a concentration of 80 wt% in DMDG, and 4 parts by weight of a photosensitive monomer (Toa Gosei Co., Aronix M315) Parts, 0.5 parts by weight of antifoaming agent (manufactured by San Nopco, S-65), 3.6 parts of NMP
The parts by weight were mixed with stirring. . After mixing 12 parts by weight of polyether sulfone (PES) and 14.49 parts by weight of an epoxy resin particle (manufactured by Sanyo Kasei Co., Ltd., polymer pole) having an average particle diameter of 0.5 μm, 30 parts by weight of NMP was further added and stirred with a bead mill. Mixed. . 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), a photoinitiator (Irgacure I-, manufactured by Ciba-Geigy)
907) 2 parts by weight, photosensitizer (DETX-S, manufactured by Nippon Kayaku) 0.2
Parts by weight and 1.5 parts by weight of NMP were mixed with stirring. These were mixed to prepare a resin composition to be used as a lower insulating layer constituting a two-layer interlayer resin insulating layer.

C. Preparation of resin filler 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell, molecular weight 310, YL983U), Si coated with a silane coupling agent on the surface and having an average particle size of 1.6 μm
O ₂ spherical particles (manufactured by Admatech, CRS 1101-CE, where the maximum particle size is not more than the thickness (15 μm) of the inner layer copper pattern described later) 170 parts by weight, leveling agent (manufactured by San Nopco, Perenol S4) 1.5 The weight of the mixture is kneaded with three rolls and the viscosity of the mixture is 45,000 ~ at 23 ± 1 ° C.
Adjusted to 49,000cps. . Imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals) 6.5
Parts by weight. These were mixed to prepare a resin filler 10.

D. Preparation Example 1 of Acrylic Ester Polymer In a xylene solvent, 2-ethylhexyl acrylate and butyl acrylate were mixed at a weight ratio of 53:47, and dimethylaniline (tertiary amine) was used as an initiator.
C. and was copolymerized by a conventional method. Similarly, ethyl acrylate and hydroxyethyl acrylate were independently polymerized. A copolymer of 2-ethylhexyl acrylate and butyl acrylate, a polymer of ethyl acrylate, and a polymer of hydroxyethyl acrylate are 2-ethylhexyl acrylate: butyl acrylate: ethyl acrylate: hydroxyethyl acrylate = 49: 42: 6: 3 by weight ratio. And xylene was removed by heating. The resulting composition was tried to reprecipitate in methanol, but the polymer did not precipitate, and the molecular weight is estimated to be about 2,000 to 3,000. About the obtained composition, FT-IR spectrum,
¹ H-NMR and ¹³ C-NMR were measured. Fig.
25, 26 and 27. From these IR and NMR data, it was confirmed that the synthesized product was a polymer of an acrylate ester.

[Measurement Apparatus and Measurement Conditions] FT-IR apparatus: Perkin Elmer 1650 Measurement method: Transmission method (KRS-5) NMR apparatus: JEOL EX-400 Chemical shift standard: CDCl ₃ ; ¹ H 7.25 ppm, ¹³ C 7
A 7.05 ppm sample was dissolved in deuterated chloroform, and 5 drops of pyridine-d5 were added, followed by measurement at room temperature.

E. Manufacturing method of printed wiring board (1) 18 μm on both sides of substrate 1 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 1 mm
A copper-clad laminate on which m copper foils 8 were laminated was used as a starting material (see FIG. 4). First, the copper clad laminate is drilled to form a plating resist, and then subjected to an electroless plating process to form a through hole 9, and further, the copper foil 8 is etched in a pattern according to a conventional method. Substrate 1
The inner layer copper pattern 4 was formed on both surfaces of the substrate.

(2) The substrate on which the inner layer copper pattern 4 and the through hole 9 were formed was washed with water and dried. Then, NaOH (10 g / l) and NaClO ₂ (40 g /
l), Na ₃ PO ₄ (6 g / l), NaOH (10 g
/ L), a roughened layer 11 was provided on the surface of the inner layer copper pattern 4 and the through hole 9 by oxidation-reduction treatment using NaBH ₄ (6 g / l) (see FIG. 5).

(3) The resin filler 10 is applied to one surface of the substrate by using a roll coater to fill the space between the conductor circuits 4 or into the through holes 9 and dried at 70 ° C. for 20 minutes. In the same way, the resin filler 10 is filled between the conductor circuits 4 or in the through holes 9 at 70 ° C., 20 ° C.
It was dried by heating for minutes (see FIG. 6).

(4) One surface of the substrate after the treatment of (3) is subjected to belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku Co., Ltd.) to form the surface of the inner layer copper pattern 4 and the through holes 9. Polishing was performed so that the resin filler 10 did not remain on the land surface, and then buffing was performed to remove scratches due to the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate. Next, a heat treatment was performed at 100 ° C. for 1 hour, at 120 ° C. for 3 hours, at 150 ° C. for 1 hour, and at 180 ° C. for 7 hours to cure the resin filler 10 (see FIG. 7).

In this manner, the surface layer of the resin filler 10 filled in the through holes 9 and the like and the roughened layer 11 on the upper surface of the inner conductor circuit 4 are removed to smooth both surfaces of the substrate.
A wiring board is firmly adhered to the side surface of the inner conductor circuit 4 via the roughened layer 11 and the inner wall surface of the through hole 9 is tightly adhered to the resin filler 10 via the roughened layer 11. Obtained. That is, by this step, the surface of the resin filler 10 and the surface of the inner layer copper pattern 4 become flush with each other. Here, the Tg point of the filled cured resin is 155.6 ° C., and the coefficient of linear thermal expansion is 44.5 × 10 ⁻⁶ /
° C.

(5) A thickness of 2.5 μm is formed on the upper surface of the land of the inner conductor circuit 4 and the through hole 9 exposed in the processing of (4).
A roughened layer (concavo-convex layer) 11 made of a Cu—Ni—P alloy was formed, and a Sn layer having a thickness of 0.3 μm was provided on the surface of the roughened layer 11 (see FIG. 8; Is not shown). The formation method is as follows. That is, the substrate was acid-degreased and soft-etched, and then treated with a catalyst solution comprising palladium chloride and an organic acid to provide a Pd catalyst. After activating this catalyst, copper sulfate 8 g / l, nickel sulfate 0.6 g / l, citric acid 15 g / l, sodium hypophosphite 29 g / l, boric acid 31 g / l, surfactant 0.1 g
Then, plating was performed in an electroless plating bath consisting of / l and pH = 9 to form a roughened layer 11 of a Cu-Ni-P alloy on the upper surface of the copper conductor circuit 4 and the upper surface of the land of the through hole 9. Further, the substrate was heated at 100 ° C for 30 minutes, at 120 ° C for 30 minutes,
C. for 2 hours, 10% by weight sulfuric acid aqueous solution, 0.1%
Treatment with 2 mol / l borofluoric acid aqueous solution, then tin borofluoride 0.1 mol / l, thiourea 1.0 mol / l, temperature 50 ° C.
A Cu—Sn substitution reaction was performed under the condition of pH = 1.2, and a Sn layer having a thickness of 0.3 μm was provided on the surface of the roughened layer 11 (the Sn layer is not shown).

(6) An interlayer resin insulating material of B (viscosity: 1.5 Pa · s) is applied to both surfaces of the substrate of (5) by a roll coater.
After being left in a horizontal state for 20 minutes, drying (prebaking) was performed at 60 ° C. for 30 minutes to form an insulating layer 2a. Further, an adhesive for electroless plating of A (viscosity 7 Pa) is placed on the insulating layer 2a.
S) was applied using a roll coater, left in a horizontal state for 20 minutes, and then dried (prebaked) at 60 ° C. for 30 minutes to form an adhesive layer 2b (see FIG. 9).

(7) The insulating layer 2a and the adhesive layer in the above (6)
A photomask film on which a black circle of 85 μmφ was printed was brought into close contact with both surfaces of the substrate on which 2b was formed, and was exposed at 500 mJ / cm ² using an ultra-high pressure mercury lamp. This is spray-developed with a DMTG solution, and the substrate is further subjected to an ultra-high pressure mercury lamp for 30 minutes.
Exposure at 100 mJ / cm ² and heat treatment (post-bake) at 100 ° C. for 1 hour and then at 150 ° C. for 5 hours
85μ with excellent dimensional accuracy equivalent to a photomask film
Thickness with mφ opening (via hole forming opening 6)
35 μm interlayer resin insulation layer (two-layer structure) 2 was formed (FIG.
10). Note that the tin plating layer was partially exposed in the opening serving as the via hole.

(8) 800 g / l of the substrate having the openings
Chromic acid at 70 ° C. for 19 minutes to dissolve and remove the epoxy resin particles present on the surface of the adhesive layer 2b of the interlayer resin insulation layer 2, thereby making the surface of the interlayer resin insulation layer 2 rough (depth) 3 μm), and then immersed in a neutralizing solution (manufactured by Shipley) and washed with water (see FIG. 11). further,
By applying a palladium catalyst (manufactured by Atotech) to the surface of the roughened substrate, catalyst nuclei were attached to the surface of the interlayer resin insulating layer 2 and the inner wall surface of the via hole opening 6.

(9) The substrate was immersed in an electroless copper plating bath having the following composition to form an electroless copper plating film 12 having a thickness of 0.6 μm on the entire rough surface (see FIG. 12). Furthermore, this electroless plating film is applied at 50 ° C for 1 hour, at 100 ° C for 30 minutes, at 120 ° C.
For 30 minutes and at 150 ° C. for 2 hours. [Electroless plating solution] EDTA 150 g / l Copper sulfate 20 g / l HCHO 30 ml / l NaOH 40 g / l α, α'-bipyridyl 80 mg / l PEG 0.1 g / l [Electroless plating conditions] 70 ° C. 30 minutes at liquid temperature

(10) Electroless copper plating film formed in (9)
A commercially available photosensitive dry film was affixed on 12 and a mask was placed thereon, exposed at 100 mJ / cm ² , developed with 0.8% sodium carbonate, and provided with a plating resist 3 having a thickness of 15 μm (FIG. 13). reference).

(11) Then, after the surface of the electroless plating film is treated with a 10% sulfuric acid aqueous solution, a portion where no resist is formed is subjected to electrolytic copper plating under the following conditions, and a 15 μm-thick electrolytic copper plating film is formed.
13 was formed (see FIG. 14). Further, the electrolytic plating film was subjected to a heat treatment at 50 ° C. for 30 minutes, at 80 ° C. for 30 minutes, at 100 ° C. for 30 minutes, at 120 ° C. for 30 minutes, and at 150 ° C. for 5 hours. [Electroplating solution] Sulfuric acid 180 g / l Copper sulfate 80 g / l Additive (Capparaside GL, manufactured by Atotech Japan) 1
ml / l [Electroplating conditions] Current density 1A / dm ² hours 30 minutes Temperature Room temperature

(12) After the plating resist 3 is peeled off with 5% KOH, the surface is treated with a 10% sulfuric acid aqueous solution, and the electroless plating film 12 under the plating resist 3 is etched with a mixed solution of sulfuric acid and hydrogen peroxide. This was treated and dissolved and removed to form a conductor circuit (including via holes) 5 having a thickness of 18 μm and comprising an electroless copper plating film 12 and an electrolytic copper plating film 13. Further, the surface of the adhesive layer for electroless plating between the conductor circuits located at the portion where the conductor circuits are not formed is immersed in 800 g / l chromic acid at 70 ° C. for 3 minutes, and the surface of the adhesive layer for electroless plating is etched by 1 to 2 μm. The remaining palladium catalyst was removed (see FIG. 15).

(13) The substrate on which the conductor circuit 5 is formed is made of copper sulfate 8 g / l, nickel sulfate 0.6 g / l, citric acid 15 g / l
1, sodium hypophosphite 29 g / l, boric acid 31 g / l,
The surface of the conductive circuit 5 was immersed in an electroless plating solution having a pH of 9 containing 0.1 g / l of a surfactant to form a roughened layer 11 of 3 μm thick made of copper-nickel-phosphorus (see FIG. 16). ). At this time, the formed roughened layer 11 is applied to EPMA (fluorescent X
Line analyzer), Cu: 98 mol%, Ni:
The composition ratio was 1.5 mol%, P: 0.5 mol%. further,
Tin borofluoride 0.1 mol / l, thiourea 1.0 mol / l, temperature
A Cu-Sn substitution reaction was performed under the conditions of 50 ° C. and pH = 1.2 to provide a 0.3 μm thick Sn layer on the surface of the roughened layer 11 (the Sn layer is not shown).

(14) By repeating the above steps (6) to (13), a further upper layer conductive circuit was formed to obtain a multilayer printed wiring board. However, Sn substitution was not performed (FIGS. 17 to 22).
reference).

(15) On the other hand, 46.67 parts by weight of a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) having a 50% epoxy group acrylated to impart photosensitivity (molecular weight: 4000), a bisphenol A type epoxy resin (oiled shell) Made,
Epicoat 1001) 14.121 parts by weight, imidazole curing agent (Shikoku Chemicals, 2E4MZ-CN) 1.6 parts by weight, photosensitive monomer polyvalent acrylic monomer (Nippon Kayaku, R604) 1.
5 parts by weight, similarly 3.0 parts by weight of a polyvalent acrylic monomer (manufactured by Kyoeisha Chemical, DPE6A) and 0.36 parts by weight of the acrylate polymer synthesized in D were mixed, and the mixture was mixed with Irgacure I907 (Ciba Geigy) as a photoinitiator. 2.0 parts by weight, DETX-S (Nippon Kayaku) as photosensitizer
0.2 parts by weight, and 1.0 part by weight of DMDG (diethylene glycol dimethyl ether) were further added.
Thus, a solder resist composition adjusted to 1.4 ± 0.3 Pa · s was obtained. The viscosity was measured using a B-type viscometer (Tokyo Keiki, D
For VL-B), rotor No. 4 was used for 60 rpm, and rotor No. 3 for 6 rpm.

(16) The solder resist composition was applied to both sides of the multilayer wiring board obtained in the above (14) in a thickness of 20 μm. Next, after performing a drying treatment at 70 ° C. for 20 minutes and at 70 ° C. for 30 minutes, a 5 mm-thick photomask film on which a circular pattern (mask pattern) is drawn is placed in close contact with the substrate, and 1000 mJ / cm ^2. And subjected to DMTG development processing. And 1 hour at 80 ° C, 1 hour at 100 ° C,
Heat treatment was performed at 20 ° C. for 1 hour and at 150 ° C. for 3 hours to form a solder resist layer (thickness: 20 μm) 14 (opening diameter: 200 μm) with a solder pad portion (including a via hole and its land portion) opened. .

(17) Next, the substrate on which the solder resist layer 14 was formed was treated with a pH of 30 g / l of nickel chloride, 10 g / l of sodium hypophosphite, and 10 g / l of sodium citrate.
= 5 for 20 minutes to form a nickel plating layer 15 having a thickness of 5 μm at the opening. Further, the substrate was placed on an electroless gold plating solution comprising 2 g / l of potassium gold cyanide, 75 g / l of ammonium chloride, 50 g / l of sodium citrate, and 10 g / l of sodium hypophosphite at 93 ° C. for 23 seconds. By dipping, a gold plating layer 16 having a thickness of 0.03 μm was formed on the nickel plating layer 15.

(18) Then, a solder paste is printed in the opening of the solder resist layer 14 and reflowed at 200 ° C. to form a solder bump (solder body) 17. A printed wiring board having the solder bump 17 is formed. It was manufactured (see FIG. 23).

The printed wiring board thus manufactured was subjected to confirmation of applicability, HAST test, confirmation of halo phenomenon, and heat cycle test in the same manner as in Example 1 and Comparative Example. The results are shown in Table 1. In addition, the solder resist layers of Example 1 and Example 2 were examined for the presence or absence of bubbles using an optical microscope. As a result, Example 1
No air bubbles were observed in the solder resist layer of Example 2, but no air bubbles were observed in the solder resist layer of Example 2. Further, the solder resist layer of Example 1 was devitrified, but the solder resist layer of Example 2 had translucency, and the developability of the solder resist layer of Example 2 was better. .

[0099]

As described above, according to the solder resist composition of the present invention, simultaneous application to both surfaces of a substrate by a roll coater is possible, and there is no migration of lead. Therefore, since the printed wiring board of the present invention does not form an oxide film on the surface of the conductive pad, there is no peeling of the solder resist layer due to a halo phenomenon or heat cycle.

[Brief description of the drawings]

FIG. 1 is a view showing one manufacturing process of a printed wiring board according to the present invention.

FIG. 2 (a) is a view showing a solder resist coating step according to the present invention, and FIG. 2 (b) is a view showing a surface structure of a coating roller used in the coating step.

FIG. 3 is a partial cross-sectional view showing a state where a solder body is provided on the printed wiring board of the present invention, wherein (a) shows a form in which the entire surface of the pad is exposed in an opening of a solder resist layer, and (b)
Shows a form in which a partial surface of the pad is exposed in the opening of the solder resist layer.

FIG. 4 is a view showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 5 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 6 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 7 is a view showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 8 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 9 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 10 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 11 is a view showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 12 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 13 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 14 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 15 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 16 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 17 is a diagram illustrating each manufacturing process of the printed wiring board according to the present invention.

FIG. 18 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 19 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 20 is a diagram illustrating each manufacturing process of the printed wiring board according to the present invention.

FIG. 21 is a diagram illustrating each manufacturing process of the printed wiring board according to the present invention.

FIG. 22 is a diagram illustrating each manufacturing process of the printed wiring board according to the present invention.

FIG. 23 is a diagram showing each manufacturing process of the printed wiring board according to the present invention.

FIG. 24 is another partial cross-sectional view showing a state in which a solder body is provided on the printed wiring board of the present invention, in which (a) is a form in which the entire surface of the pad is exposed in the opening of the solder resist layer
(b) shows a form in which a part of the surface of the pad is exposed in the opening of the solder resist layer.

25 is a diagram showing an FT-IR spectrum of a polymer of an acrylate ester synthesized in Example 2. FIG.

26 is a diagram showing a ¹ H-NMR spectrum of a polymer of an acrylate ester synthesized in Example 2. FIG.

FIG. 27 is a diagram showing a ¹³ C-NMR spectrum of a polymer of an acrylate ester synthesized in Example 2.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 interlayer resin insulating layer (adhesive layer for electroless plating) 2a insulating layer 2b adhesive layer 3 plating resist (permanent resist) 4 inner conductor circuit (inner copper pattern) 5 outer conductor circuit (outer copper pattern) 6 Via hole opening 7 Via hole (BVH) 8 Copper foil 9 Through hole 10 Filling resin (resin filler) 11 Roughening layer 12 Electroless copper plating film 13 Electrolytic copper plating film 14 Solder resist layer 15 Nickel plating layer 16 Gold plating Layer 17 Solder bump 18 Roll coater 19 Coating roller 20 Doctor bar

Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 33:00) C08L 33:00) (72) Inventor Motoo Asai 1-1 Ibigawa-cho, Ibi-gun, Ibi-gun, Gifu Prefecture Inside IBIDEN Corporation (56 References JP-A-8-242064 (JP, A) JP-A-5-194902 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 1/00-3/46 C08G 59/17 C08L 63/10

Claims (9)

(57) [Claims] 1. Acryl of novolak type epoxy resin
Weight, imidazole curing agent and acrylic ester
And a polymer of the acrylate ester having a molecular weight of 500 to 5,000.
Wherein acrylic acid or methacrylic acid has 1 carbon atom
It is a polymer of ester with alcohol of ~ 10
A solder resist composition according to the present invention. 2. Acryl of novolak type epoxy resin
Weight, imidazole curing agent and acrylic ester
And a polymer of the acrylate ester having a molecular weight of 500 to 5000.
Wherein acrylic acid or methacrylic acid has 1 carbon atom
A polymer of an ester with an alcohol of up to 10
0.5 ~ 10P at 25 ° C using recol ether ether solvent
A solder resist composition adjusted to a · s. 3. An initiator having a structure represented by the following chemical formula 1.
A compound of the following formula 2 as a photosensitizer:
3. A compound comprising a compound having the formula:
3. The solder resist composition according to item 1. Embedded image Embedded image 4. The imidazole curing agent is liquid at room temperature.
The solder resist composition according to claim 1, wherein
Thing . 5. A semiconductor device on a surface of a wiring board on which a conductive circuit is formed.
In a printed wiring board having a solder resist layer, the solder resist layer is a novolak type epoxy resin.
Acrylate, imidazole curing agent, and acrylic acid
And a polymer of an ester, wherein the polymer of the acrylate ester has a molecular weight of 500 to 5,000.
Wherein acrylic acid or methacrylic acid has 1 carbon atom
A polymer of an ester with an alcohol of up to 10
0.5 ~ 10 viscosity at 25 ° C using recol ether solvent
Cure the solder resist composition adjusted to Pa · s
A printed wiring board characterized by being formed . 6. A wiring board on which a conductive circuit is formed is provided.
A solder resist layer on the surface of
The conductor circuit exposed from the opening provided in the resist layer
Is formed as a pad, and the solder
In the printed wiring board formed by supplying hold, the solder resist layer is a novolac type epoxy resin
Acrylate, imidazole curing agent, and acrylic acid
And a polymer of an ester, wherein the polymer of the acrylate ester has a molecular weight of 500 to 5,000.
Wherein acrylic acid or methacrylic acid has 1 carbon atom
It is a polymer of ester with alcohol of ~ 10
Printed wiring board. 7. The method according to claim 1, wherein the solder resist layer is used as an initiator.
And a compound having the structure of the following chemical formula 3 and a photosensitizer
And a compound having a structure represented by the following chemical formula 4.
The printed wiring board according to claim 5 or 6, wherein Embedded image Embedded image 8. A roughened layer is formed on a surface of the conductor circuit.
The printed wiring board according to claim 5, wherein the printed wiring board is formed . 9. The roughening layer is made of copper-nickel-phosphorus.
The printed wiring board according to claim 8, wherein the printed wiring board is an alloy layer .